Compositions and methods for crossing the blood-brain barrier

Abstract

Disclosed herein is a novel blood-brain barrier (BBB) ​​penetrating receptor on the BBB interface, a targeting peptide and its derivatives that can bind to the novel receptor, and related methods of using the receptor to increase the permeability of the BBB and deliver agents to the nervous system (e.g., CNS). In some embodiments, the BBB penetrating receptor is carbonic anhydrase IV. Also disclosed herein is a recombinant adeno-associated virus (rAAV) with increased specificity and transduction efficiency across the BBB and related compositions and methods for treating various diseases and conditions.

Description

[Technical field]

[0001] Related Applications This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 63 / 316,298, filed March 3, 2022, U.S. Provisional Patent Application No. 63 / 359,168, filed July 7, 2022, and U.S. Provisional Patent Application No. 63 / 480,279, filed January 17, 2023. The contents of these related applications are incorporated herein by reference in their entirety for all purposes.

[0002] STATEMENT REGARDING FEDERALLY SPONSORED R&D This invention was made with Government support under Grant No. NS111369 awarded by the National Institutes of Health. The Government has certain rights in this invention.

[0003] Sequence Listing Reference This application is filed with an electronic sequence listing, which is provided as a file entitled 30KJ-302459-WO-SeqList, created on March 2, 2023, and is 258 kilobytes in size. The information in the electronic format of the sequence listing is incorporated herein by reference in its entirety. [Background technology]

[0004] background Field The present disclosure relates to methods and targeting peptides for crossing the blood-brain barrier.

[0005] Description of Related Technical Field The blood-brain barrier (BBB) ​​presents a fundamental bottleneck to the development of effective research tools and therapeutics for the central nervous system (CNS). This structure, which primarily contains brain endothelial cells, requires large molecules to be delivered by invasive intracranial injections, technically challenging focused ultrasound, or receptor-mediated transcytosis. The rational design of BBB-crossing large molecules has long been hampered by an incomplete understanding of the mechanisms involved in transcytosis, with only a few targets, such as the transferrin receptor, validated for research and therapy.

[0006] Therefore, identification of BBB-penetrating targets, mechanisms, molecules and methods is necessary to improve the efficiency of research tools and treatments directed at the CNS. Summary of the Invention [Means for solving the problem]

[0007] Abstract Disclosed herein is a method of increasing blood-brain barrier permeability. The method, in some embodiments, includes providing a targeting peptide capable of binding to carbonic anhydrase IV, thereby increasing blood-brain barrier permeability. In some embodiments, at least one activity of carbonic anhydrase IV is decreased by binding to the targeting peptide. Also provided is a method of increasing blood-brain barrier permeability. The method, in some embodiments, includes decreasing carbonic anhydrase IV activity, thereby increasing blood-brain barrier permeability. In the methods disclosed herein, the targeting peptide can bind, for example, to the zinc binding site and / or hydrophobic substrate binding pocket of carbonic anhydrase IV. In some embodiments, the blood-brain barrier permeability is increased by at least 25%, 50%, 75%, 100% or more compared to the absence of the target peptide or the decrease in carbonic anhydrase IV activity. Also provided herein is a method of delivering a payload to the nervous system. The method, in some embodiments, includes providing a targeting peptide capable of binding to carbonic anhydrase IV or a derivative thereof, where the targeting peptide is part of a delivery system, and the delivery system comprises a payload to be delivered to the nervous system, and administering the delivery system to a subject.

[0008] As disclosed herein, the delivery system may include, for example, nanoparticles, nanotubes, nanowires, dendrimers, liposomes, ethosomes and aquasomes, polymersomes and niosomes, foams, hydrogels, cubosomes, quantum dots, exosomes, macrophages, and combinations thereof. In some embodiments, the delivery system includes a viral vector or a non-viral vector. The viral vector may include, for example, an adenoviral vector, an AAV vector, a lentiviral vector, or a retroviral vector. In some embodiments, the target peptide is part of the capsid protein of an AAV vector. The AAV vector can be a vector selected from AAV1, AAV2, AAV3, AAV3b, AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, AAV10, AAV-DJ, human isolate hu.31, human isolate hu.32, rhesus isolate rh.8, rhesus isolate rh.10, and variants thereof. In some embodiments, the AAV vector is AAV9. Non-viral vectors can include, for example, lipid-based nanoparticles, polymeric nanoparticles, inorganic nanoparticles, surfactant-based emulsions, nanowires, silica nanoparticles, peptide or protein-based particles, lipid-polymer particles, nanolipoprotein particles, and combinations thereof.

[0009] In some embodiments, the payload delivered to the nervous system is a biological molecule, a non-biological molecule, or a combination thereof. The biological molecule can be a nucleic acid sequence, a protein, a peptide, a lipid, a polysaccharide, or a combination thereof. In some embodiments, the payload is a therapeutic molecule. In some embodiments, the nucleic acid sequence delivered to the nervous system includes one or more of: a) a trophic factor, a growth factor, or other soluble factor that can be released from the transduced cell and affect the survival or function of the cell and / or surrounding cells; b) a cDNA that restores protein function to a human or animal with a genetic mutation in that gene; c) a cDNA that encodes a protein that can be used to control or modify the activity or state of a cell; d) a cDNA that encodes a protein or nucleic acid that is used to evaluate the state of a cell; e) a cDNA and / or associated guide RNA for performing genome manipulation; f) a sequence for genome editing by homologous recombination; g) a DNA sequence that encodes a therapeutic RNA; h) an shRNA or artificial miRNA delivery system; or i) a DNA sequence that affects the splicing of an endogenous gene.

[0010] In some embodiments, the carbonic anhydrase IV is mouse carbonic anhydrase IV. In some embodiments, the carbonic anhydrase IV has an amino acid sequence having at least 80% sequence identity to the amino acid sequence of SEQ ID NO: 179. In some embodiments, the carbonic anhydrase IV is human carbonic anhydrase IV. In some embodiments, the carbonic anhydrase IV has an amino acid sequence having at least 80% sequence identity to the amino acid sequence of SEQ ID NO: 180. In some embodiments, the targeting peptide, when bound, is: (1) one or more of the following functionally equivalent to S20, G21, W22, L36, W41, P42, E90, V111, Q112, H114, H139, V141, K143, F156, L217, T218, T219, P220, N221, D223, or W228 in carbonic anhydrase IV having the amino acid sequence of SEQ ID NO: 179; or (2) one or more positions functionally equivalent to S21, H22, W23, L37, W42, G43, M92, K113, Q114, H116, H141, V143, E145, Q158, L224, T225, T226, P227, T228, D231, or W236 in carbonic anhydrase IV having the amino acid sequence of SEQ ID NO: 180. In some embodiments, the targeting peptide comprises (1) an amino acid sequence selected from the group consisting of SEQ ID NOs: 70-174, or (2) an amino acid sequence having at least 80% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 70-174. In some embodiments, the targeting peptide comprises an amino acid sequence selected from SEQ ID NOs: 70-108. In some embodiments, the targeting peptide comprises an amino acid sequence selected from SEQ ID NOs: 70-86. In some embodiments, the targeting peptide comprises (1) an amino acid sequence selected from the group consisting of AKPTPLLGLLQAQTG (SEQ ID NO: 70), AKPTPLLLLLQAQTG (SEQ ID NO: 71), AQPPLGGLLAQAQTG (SEQ ID NO: 72), AKPPGPWAEAQAQTG (SEQ ID NO: 73), and AQPPLLGGLAQAQTG (SEQ ID NO: 74), or (2) an amino acid sequence having at least 80% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 70-74.In some embodiments, the targeting peptide is inserted between two adjacent amino acids in AA587-594 of SEQ ID NO: 178 of the AAV9 vector, or a functional equivalent of AA587-594 in an amino acid sequence at least 80% identical to SEQ ID NO: 178. In some embodiments, the targeting peptide is inserted between AA588-589 of SEQ ID NO: 178 of the AAV9 vector, or a functional equivalent of AA588-589 in an amino acid sequence at least 80% identical to SEQ ID NO: 178. The AAV vector can be conjugated to, for example, a nanoparticle, a second molecule, or a combination thereof.

[0011] The administration can be systemic. In some embodiments, the administration is intravenous. In some embodiments, the administration is intrathecal. The subject can be, for example, a mammal. In some embodiments, the subject is a human. In some embodiments, the subject is a subject suffering from or at risk of developing one or more of chronic pain, Huntington's disease (HD), Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), spinal muscular atrophy types I and II (SMA I and II), Friedreich's ataxia (FA), spinocerebellar ataxia, multiple sclerosis (MS), chronic traumatic encephalopathy (CTE), HIV-1 associated dementia, or a lysosomal storage disorder involving cells in the CNS. The lysosomal storage disorder involving cells in the CNS can be, for example, Krabbe disease, Sandhoff disease, Tay-Sachs disease, Gaucher disease (types I, II, or III), Niemann-Pick disease (NPC1 or NPC2 deficiency), Hurler syndrome, Pompe disease, or Batten disease. In some embodiments, the subject has, is at risk for, or has had a stroke, traumatic brain injury, epilepsy, or spinal cord injury.

[0012] Disclosed herein is an AAV capsid protein comprising a targeting peptide having binding specificity for carbonic anhydrase IV. In some embodiments, the targeting peptide is part of a capsid protein of a rAAV vector. In some embodiments, the targeting peptide is inserted between two adjacent amino acids at AA587-594 of SEQ ID NO: 178, or a functional equivalent of AA587-594 in an amino acid sequence at least 80% identical to SEQ ID NO: 178. In some embodiments, the targeting peptide comprises: (1) an amino acid sequence selected from the group consisting of SEQ ID NOs: 70-174; (2) an amino acid sequence having at least 80% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 70-174. The AAV vector can be, for example, AAV1, AAV2, AAV3, AAV3b, AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, AAV10, AAV-DJ, human isolate hu.31, human isolate hu.32, rhesus isolate rh.8, rhesus isolate rh.10, or a variant thereof. In some embodiments, the AAV vector is AAV9.

[0013] Disclosed herein is a recombinant adeno-associated virus (rAAV) comprising any of the AAV capsid proteins disclosed herein. Disclosed herein is an rAAV comprising an AAV capsid protein comprising a targeting peptide having binding specificity for carbonic anhydrase IV, wherein the amino acid sequence of the targeting peptide is inserted between two adjacent amino acids at AA587-594 of the AAV capsid protein, or a functional equivalent thereof. In some embodiments, the two adjacent amino acids are AA588 and AA589. In some embodiments, the targeting peptide comprises (1) an amino acid sequence selected from SEQ ID NOs: 70-174, or (2) an amino acid sequence having at least 80% sequence identity to an amino acid sequence selected from SEQ ID NOs: 70-174.

[0014] Disclosed herein is a composition for use in the delivery of an agent to the nervous system of a subject in need thereof. The composition, in some embodiments, comprises an AAV comprising (1) any of the AAV capsid proteins disclosed herein and (2) an agent to be delivered to the nervous system of the subject. In some embodiments, the nervous system is the central nervous system (CNS), the peripheral nervous system (PNS), or a combination thereof. The nervous system may be, for example, brain endothelial cells, neurons, capillaries in the brain, arterioles in the brain, arteries in the brain, or a combination thereof. In some embodiments, the composition is a pharmaceutical composition comprising one or more pharma- ceutical acceptable carriers. In some embodiments, the agent to be delivered comprises a nucleic acid, a peptide, a small molecule, an aptamer, or a combination thereof.

[0015] Disclosed herein is an antibody or fragment thereof comprising an amino acid sequence having binding specificity for carbonic anhydrase IV. In some embodiments, the antibody or fragment thereof comprises (1) an amino acid sequence selected from the group consisting of SEQ ID NOs: 70-174, or (2) an amino acid sequence having at least 80% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 70-174. In some embodiments, the antibody or fragment thereof is a bispecific antibody comprising at least one Fab having specificity for carbonic anhydrase IV. The antibodies disclosed herein include antibody conjugates comprising any one of the antibodies disclosed herein or fragments thereof. In some embodiments, the antibody conjugate further comprises a therapeutic agent or a detectable label.

[0016] Disclosed herein is a peptide having specificity for carbonic anhydrase IV or a derivative or conjugate thereof. Disclosed herein is a nucleic acid comprising a sequence encoding any one of the antibodies disclosed herein or a fragment thereof, or any of the peptides disclosed herein or a derivative or conjugate thereof.

[0017] Disclosed herein is a delivery system comprising (1) a targeting peptide having specificity for carbonic anhydrase IV and (2) an agent. In some embodiments, the targeting peptide is (1) presented on the surface of the delivery system or (2) partially embedded in the delivery system. In some embodiments, the delivery system is selected from nanoparticles, nanotubes, nanowires, dendrimers, liposomes, ethosomes and aquasomes, polymersomes and niosomes, foams, hydrogels, cubosomes, quantum dots, exosomes, macrophages, and combinations thereof. In some embodiments, the delivery system comprises a viral vector or a non-viral vector. In some embodiments, the delivery system comprises a nanoparticle selected from lipid-based nanoparticles, polymeric nanoparticles, inorganic nanoparticles, surfactant-based emulsions, nanowires, silica nanoparticles, virus-like particles, peptide or protein-based particles, lipid-polymer particles, nanolipoprotein particles, and combinations thereof.

[0018] Disclosed herein are methods for designing targeting peptides with specificity for carbonic anhydrase IV. The methods, in some embodiments, involve: (1) targeting one or more positions functionally equivalent to S20, G21, W22, L36, W41, P42, E90, V111, Q112, H114, H139, V141, K143, F156, L217, T218, T219, P220, N221, D223, or W228 in carbonic anhydrase IV having an amino acid sequence of SEQ ID NO: 179; or (2) targeting one or more positions functionally equivalent to S20, G21, W22, L36, W41, P42, E90, V111, Q112, H114, H139, V141, K143, F156, L217, T218, T219, P220, N221, D223, or W228 in carbonic anhydrase IV having an amino acid sequence of SEQ ID NO: 180. In some embodiments, generating one or more targeting peptides in silico includes generating one or more targeting peptides capable of interacting with one or more positions functionally equivalent to S21, H22, W23, L37, W42, G43, M92, K113, Q114, H116, H141, V143, E145, Q158, L224, T225, T226, P227, T228, D231, or W236 in carbonic anhydrase IV having the sequence of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, generating a plurality of candidate peptides in silico and performing a computer-assisted docking simulation for each of the plurality of candidate peptides that bind to carbonic anhydrase IV; and (1) determining whether or not a position or positions functionally equivalent to S20, G21, W22, L36, W41, P42, E90, V111, Q112, H114, H139, V141, K143, F156, L217, T218, T219, P220, N221, D223, or W228 in carbonic anhydrase IV having an amino acid sequence of SEQ ID NO: 179; or (2) analyzing the structure of carbonic anhydrase IV bound to one or more candidate peptides to identify one or more targeting peptides capable of interacting with one or more positions functionally equivalent to S21, H22, W23, L37, W42, G43, M92, K113, Q114, H116, H141, V143, E145, Q158, L224, T225, T226, P227, T228, D231 or W236 in carbonic anhydrase IV having the amino acid sequence of SEQ ID NO: 180.In some embodiments, the method includes obtaining a binding score for each of a plurality of candidate peptides that bind to carbonic anhydrase IV, and selecting one or more of the plurality of candidate peptides having a binding score above a threshold as a targeting peptide having specificity for carbonic anhydrase IV. In some embodiments, the method includes comparing the binding scores of two or more of the plurality of candidate peptides to rank the candidate peptide sequences. In some embodiments, obtaining a binding score for each of the plurality of candidate peptide sequences includes (1) counting the total number of atoms at the interface between the candidate peptide and carbonic anhydrase IV, (2) counting the total number of atoms in the candidate peptide, where the atoms are in collision with carbonic anhydrase IV, (3) obtaining a bond angle of the candidate peptide, and (4) obtaining a binding depth of the candidate peptide.

[0019] Disclosed herein is a method for increasing the permeability of the blood-brain barrier in a mouse species. The method, in some embodiments, comprises providing a targeting peptide capable of binding to Ly6c1, thereby increasing the permeability of the blood-brain barrier in a mouse species. In some embodiments, the targeting peptide has an amino acid sequence selected from the group consisting of 1) AQRYQGDSVAQ (SEQ ID NO: 7), AQWSTNAGYAQ (SEQ ID NO: 8), AQERVGFAQAQ (SEQ ID NO: 9), AQWMTHGSAAQ (SEQ ID NO: 10), and SPRYKGDSVAQ (SEQ ID NO: 57), or (2) an amino acid sequence having at least 80% sequence identity with an amino acid sequence selected from the group consisting of AQRYQGDSVAQ (SEQ ID NO: 7), AQWSTNAGYAQ (SEQ ID NO: 8), AQERVGFAQAQ (SEQ ID NO: 9), AQWMTHGSAAQ (SEQ ID NO: 10), and SPRYKGDSVAQ (SEQ ID NO: 57). In some embodiments, the targeting peptide has an amino acid sequence of SPRYKGDSVAQ (SEQ ID NO: 57), or an amino acid sequence having at least 80% identity to SEQ ID NO: 57. In some embodiments, the targeting peptide is inserted between two adjacent amino acids at AA587-590 of SEQ ID NO: 178, or a functional equivalent of AA587-590 in an amino acid sequence at least 80% identical to SEQ ID NO: 178. [Brief description of the drawings]

[0020] BRIEF DESCRIPTION OF THE DRAWINGS [Figure 1A]1A-1C show non-limiting exemplary embodiments and data regarding the identification of engineered AAV that did not utilize Ly6a for BBB crossing. FIG. 1A shows that AAV-PHP.eB can efficiently cross the BBB using membrane-localized Ly6a in C57BL / 6J mice, but not GPI-disrupted Ly6a in BALB / cJ mice. FIG. 1B shows a clustering analysis of CNS-tropic engineered AAV insertion sequences. The thickness of the connecting lines represents the degree of relatedness between the nodes. AAVs in the box in the upper left corner showed high relatedness to PHP.eB. AAVs outside the box showed little relatedness to PHP.eB or to each other. The AA sequences inserted between positions 588-589 and 452-458 of the AAV9 capsid of each variant are shown. FIG. 1C shows surface plasmon resonance (SPR) of engineered AAV binding to Ly6a-Fc captured on a Protein A chip. Data are representative of two independent experiments. [Figure 1B-1] Same as above. [Figure 1B-2] Same as above. [Figure 1C-1] Same as above. [Figure 1C-2] Same as above. [Figure 1C-3] Same as above. [Figure 1C-4] Same as above. [Figure 1C-5] Same as above. [Figure 1C-6] Same as above. [Figure 1C-7] Same as above.

[0021] [Figure 2A-1]2A-2C show non-limiting exemplary embodiments and data regarding the performance of Ly6a-independent AAV across mouse strains. FIG. 2A shows transduction with AAV-PHP.eB, AAV-PHP.N, AAV-PHP.C1-C4, and AAV-F in the thalamic brain region of 129S1 / SvlmJ (membrane-localized Ly6a), CBA / J (GPI-disrupted Ly6a), DBA / 2J (membrane-localized Ly6a), and NOD / ShiLtJ (GPI-disrupted Ly6a) mice shown from sagittal brain sections. All images were acquired under the same image settings, except for the lower left quadrant of the PHP.eB image across strains, which was optimized for DBA / 2J. The indicated capsids were used to package ssAAV:CAG-mNeonGreen and administered to 6-8 week old adult mice (n=2 / group, 1 x 10 viral genomes (vg) per mouse delivered iv, 3 weeks of expression). All images were from one experiment where all viruses were freshly prepared and titrated in the same assay to ensure consistent dosing. Figure 2B shows a mouse phylogenetic tree including the strains used. Figure 2C shows the thalamic mean pixel intensity across animals. Each data point represents one animal and the bars indicate the mean value. [Figure 2A-2] Same as above. [Figure 2A-3] Same as above. [Figure 2B] Same as above. [Figure 2C-1] Same as above. [Figure 2C-2] Same as above.

[0022] [Figure 3A]Figures 3A-G show non-limiting exemplary embodiments and data on novel receptors that enhance infectivity of engineered AAV in vitro. Figure 3A shows a plot of membrane protein differential expression scores in endothelial cells calculated with Scanpy versus average transcript abundance in endothelial cells constructed from single-cell RNA sequencing of C57BL / 6J cortex. Proteins selected for cell culture screening are indicated by larger dots (Table 3), and hits are labeled and marked with crosses. Figure 3B shows screening of potential receptors in cell culture by comparing AAV fluorescent protein transgene levels at low multiplicity of infection (MOI) in mock-transfected cells and cells transfected with each potential receptor. Figure 3C shows dose-dependence of AAV9 and PHP.eB packaging CAG-mNeonGreen in HEK293T cells in 96-well plates. At 1 × 109 v.g. per well, PHP.eB had a significantly higher potency than AAV9 in Ly6a-transfected HEK293T cells. Scale indicates degree of infection (max: 0.75, min: 0.03) and total brightness per signal area (max: 0.79, min: 0.39). Figure 3D shows the potency of engineered AAVs on HEK293T cells transfected with a panel of potential receptors. Degree of infection (left, max: 0.33, min: 0.001; right, max: 0.55, min: 0.03). Total brightness per signal area (left, max: 0.55, min: 0.06; right, max: 0.61, min: 0.11). Figure 3E shows representative images of HEK cells mock transfected (none) or transfected with potential receptors (infected at 1 x 109 v.g. per well of AAV packaged with CAG-mNeonGreen) cultured in 96-well plates (left two columns are Ly6a-conjugated AAV) and imaged 24 h after transduction. An overlay of brightfield and fluorescent images is presented. Scale bar = 200 μm.Figure 3F shows the amino acid frequency by position among engineered AAVs found to have infectivity enhancement by Ly6a (6 viruses), Ly6c1 (SEQ ID NO: 293; 9 viruses) and Car4 (SEQ ID NO: 179; 2 viruses). Figure 3G shows the potency of engineered AAVs on HEK293T cells transfected with Ly6 and Car family potential receptors. The degree of infection (left, max: 0.51, min: 0.03; right, max: 0.52, min: 0.05). The total brightness per signal area (left, max: 0.75, min: 0.13; right, max: 0.79, min: 0.34). [Figure 3B] Same as above. [Figure 3C] Same as above. [Figure 3D] Same as above. [Figure 3E] Same as above. [Figure 3F] Same as above. [Figure 3G] Same as above.

[0023] [Figure 4A]4A-C show non-limiting exemplary embodiments and data regarding the role of carbonic anhydrase IV in the CNS efficacy of Car4-dependent AAV. FIG. 4A shows immunostaining of Car4 in the brains of WT / WT and KO / KO Car4 mice. Magnified areas from WT / WT demonstrate endothelial expression across diverse brain regions. FIG. 4B shows fluorescent images from transgene expression assays in whole brain and liver of WT / WT Car4 mice administered AAV-PHP.eB, 9P31 and 9P36. AAV-PHP.eB, 9P31 and 9P36 packaged with mNeonGreen under the control of the ubiquitous CAG promoter were administered intravenously to WT / WT Car4 mice at a dose of 3×10 v.g. per animal (n=3 per condition). Three weeks after administration, transgene expression was assayed by mNeonGreen fluorescence in whole brain and liver. Figure 4C shows fluorescence images from transgene expression assays in the brine and whole liver of KO / KO Car4 mice administered AAV-PHP.eB, 9P31 and 9P36. AAV-PHP.eB, 9P31 and 9P36 packaged with mNeonGreen under the control of the ubiquitous CAG promoter were administered intravenously to KO / KO Car4 mice at a dose of 3x1011 v.g. per animal (n=3 per condition). Three weeks after administration, transgene expression was assayed by mNeonGreen fluorescence in the brain and whole liver. Scale bar=2mm. [Figure 4B] Same as above. [Figure 4C] Same as above.

[0024] [Figure 5A-1]Figures 5A-5D show non-limiting exemplary embodiments and data related to engineering enhanced Ly6c1-dependent AAV. Figure 5A shows the AAV library design strategy. A scanning 3-mer library of PHP.C1-C4 was constructed as indicated by the X indicating the location of the NNK codon. AAVs were pooled and subjected to two rounds of M-CREATE selection in 6-8 week old Cre transgenic mice. Figure 5B shows round 2 selection of brain enrichment in diverse Cre transgenic and wild type mice administered the selection control AAV and 20 capsid variants selected for further study. Yields were determined during small scale production for final screening between strains. Figure 5C shows the potency in cell culture infectivity assays of PHP.eB, PHP.C2 and PHP.eC (variant 19 in Figure 5B) in mock (none) or Ly6c1 receptor transfected HEK293T cells, demonstrating that PHP.eC retained the Ly6c1 interaction. Extent of infection (max: 0.93, min: 0.02); Total brightness per signal area (max: 0.74, min: 0.16). Figure 5D shows fluorescence images from transgene expression assays in whole brain and liver of NOD / ShiLtJ and BALB / cJ mice administered PHP.C2 and PHP.eC packaged with mNeonGreen under the control of the ubiquitous CAG promoter were administered intravenously to NOD / ShiLtJ and BALB / cJ mice at a dose of 3 x 1011 v.g. per animal (n = 3 per condition). Three weeks after administration, transgene expression was assayed by mNeonGreen fluorescence in whole brain and liver, demonstrating increased potency of PHP.eC. Sagittal image scale bar = 2 mm; brain region scale bar = 250 μm. [Figure 5A-2] Same as above. [Figure 5B-1] Same as above. [Figure 5B-2] Same as above. [Figure 5C] Same as above. [Figure 5D-1] Same as above. [Figure 5D-2] Same as above.

[0025] [Figure 6A]Figures 6A-G show non-limiting exemplary embodiments and data related to in silico prediction of engineered AAV receptor and Ly6a interaction complex poses. Figure 6A shows an overview of AlphaFold2-based in silico automated pairwise peptide receptor analysis for screening engineered AAV (APPRAISE-AAV). Surface peptides from AAV variants were entered into pairwise binding competitions using AlphaFold2. Peptide competition metrics were calculated according to the interface energy, bond angle and pocket depth of each peptide before being assembled into a broader ranked matrix of interaction likelihoods. Competition results reflect relative peptide binding probabilities encoded into the AlphaFold2 neural network. Figure 6B shows a table of engineered AAV capsids, their confirmed receptors, and capsid peptide sequences used in APPRAISE-AAV. Figure 6C shows a matrix ranking AAV peptides by their average competition metrics across 10 replicate conditions for Ly6a, Ly6c1 and mouse Car4. Bold AAV peptide labels indicate those experimentally identified to interact with the corresponding receptor. Out-of-range metric values ​​(-100 to 100) were constrained to the range limits. Figure 6D shows the AlphaFold2 predicted Ly6a-PHP.eB peptide complex structure. PHP.eB peptides were colored by their pLDDT (predicted local distance difference test) score, a per-residue estimate of model confidence. The highest confidence side chains P5' and F6' are shown as spheres. The Ly6a A58R mutation, selected to disrupt predicted peptide interactions, resulted in reduced potency in cell culture infectivity assays. Degree of infection (max: 0.29, min: 0.03); and total brightness per signal area (max: 0.61, min: 0.16). Figure 6E shows Ly6a residues with at least two atoms within 5 angstroms (Å) of the modeled PHP.eB peptide. Figure 6F shows the complete model of the PHP.eB trimer and Ly6a complex.The AlphaFold2 structural predictions from Figure 6D were combined with the capsid monomer receptor structural predictions and optimized using Rosetta Remodel within the context of the AAV trimer (Figure 13A). Figure 6G shows a close-up view of the PHP.eB-Ly6a binding interface in the modeled PHP.eB-Ly6a complex and PHP.eB residues with at least two atoms within 5 Å of Ly6a. [Figure 6B] Same as above. [Figure 6C] Same as above. [Figure 6D] Same as above. [Figure 6E] Same as above. [Figure 6F] Same as above. [Figure 6G] Same as above.

[0026] [Figure 7A]Figures 7A-7D show non-limiting exemplary embodiments and data regarding the interaction of engineered AAV with carbonic anhydrase IV. Figure 7A shows the AlphaFold2 predicted mouse Car4-9P31 peptide complex structure. The 9P31 peptide is colored by the pLDDT score of each residue, with the highest confidence side chain shown as a sphere. Figure 7B shows a cutaway view of the mouse Car4 catalytic pocket with the modeled 9P31 peptide binding pose (top left) and the crystallographic Brinzolamide binding pose (PDB ID: 3ZNC, top right). Cell culture infectivity assay of the effect of Brinzolamide on engineered AAV (bottom). Extent of infection (max: 0.63, min: 0.04). Total brightness per signal area (max: 0.75, min: 0.18). Figure 7C shows a diagram of the amino acid side chains that differ between mouse (PDB ID: 3ZNC) and human (PDB ID: 1ZNC) carbonic anhydrase IV with respect to Brinzolamide and the 9P31 peptide binding pose. Figure 7D shows the potency in cell culture infectivity assays of 9P31 and 9P36 in HEK293T cells transfected with mouse, rhesus or human carbonic anhydrase IV receptors, as well as two chimeric receptors of mouse and human carbonic anhydrase IV that exchange the loop sequences shown. Extent of infection (left, max: 0.52, min: 0.05; right, max: 0.65, min: 0.03). Total brightness per signal area (left, max: 0.78, min: 0.46; right, max: 0.75, min: 0.13). [Figure 7B] Same as above. [Figure 7C] Same as above. [Figure 7D] Same as above.

[0027] [Figure 8A-1]8A-8C show non-limiting exemplary embodiments and data on low-dose AAV performance across mouse strains. FIG. 8A shows low-dose AAV performance across mouse strains corresponding to sagittal sections in FIG. 2A for 129S1 / SvlmJ, CBA / J, DBA / 2J and NOD / ShiLtJ mice injected retro-orbitally with engineered AAVs packaged with 1×10 v.g. CAG-mNeonGreen per animal (n=2). Mice were 6-8 weeks old at the time of injection and tissues were harvested 3 weeks after injection. Scale bar=2 mm. FIG. 8B shows quantification of mean fluorescence intensity in thalamic brain regions of male and female 129S1 / SvlmJ and CBA / J mice injected retro-orbitally with PHP.C1 or PHP.C2 (n=2) packaged with 1×10 v.g. CAG-mNeonGreen per animal. Mice were 6-8 weeks old at the time of injection. Tissues were harvested 3 weeks after injection. Each data point represents one animal and bars indicate the mean. Figure 8C shows AAV-PHP.C3 potency in C57BL / 6J, CBA / J and F1 crossbreed mice. Animals were injected retro-orbitally with 3 x 1011 v.g. of AAV-PHP.C3 packaged with CAG-mNeonGreen at 6-8 weeks of age. Tissues were harvested 3 weeks after injection. Thalamus was imaged to assay viral potency. [Figure 8A-2] Same as above. [Figure 8B] Same as above. [Figure 8C] Same as above.

[0028] [Figure 9A-1]9A-9C show non-limiting exemplary embodiments and data relating to representative images from cell culture infectivity assays. FIG. 9A shows fluorescence images showing dose-dependence of AAV9 and PHP.eB packaged with CAG-mNeonGreen in HEK293T cells in 96-well plates. At 1×109 v.g. per well, PHP.eB has significantly higher potency than AAV9 in Ly6a-transfected HEK293T cells. Representative images shown. Scale bar=500 μm. FIG. 9B shows representative images of HEK cells cultured in 96-well plates mock transfected (none) or transfected with potential receptors (infected with 1×109 v.g. per well of PHP.B sequence family AAV (AAV labeled "Ly6a AAV" was Ly6a binding) or Ly6a-independent AAV packaged with CAG-mNeonGreen (labeled Ly6a-independent AAV)) and imaged 24 h after transduction. Overlays of brightfield and fluorescent images are presented. Scale bar=200 μm. FIG. 9C shows representative images of HEK cells cultured in 96-well plates mock transfected (none) or transfected with Ly6a or Slco1c1. Slco1c1-infected cells showed dim and diffuse fluorescence extending beyond the cell borders for all AAVs tested. Overlays of brightfield and fluorescent images are presented. Scale bar=200 μm. [Figure 9A-2] Same as above. [Figure 9B-1] Same as above. [Figure 9B-2] Same as above. [Figure 9B-3] Same as above. [Figure 9B-4] Same as above. [Figure 9C] Same as above.

[0029] [Figure 10A]10A shows non-limiting exemplary embodiments and data regarding expression of selected membrane proteins from cell culture screening confirmed by immunofluorescence. DAPI and immunofluorescence (IF) overlays of untransfected and receptor-transfected HEK293T cells stained with the indicated antibodies, as well as the IF channel alone from the receptor-transfected HEK293T cell image (left). Scale bar = 50 μm. [Figure 10B] Non-limiting exemplary brightfield images (left in each row) and fluorescence images (right in each row) of PHP.eB, CAP-B10 packaging PHP.N and CAG-mNeonGreen, and CAP-B22 packaging CAG-NLS-GFP at two different doses in mock-transfected and Ly6a-expressing cells are shown. Ly6a-interacting AAV engineered from PHP.eB shows similar potency enhancement in cell culture. Scale bar = 100 μm. [Figure 10C] Figure 10C shows non-limiting exemplary embodiments and data on the potency of CAP-B10 and CAP-B22. CAP-B10 and CAP-B22 did not show potency enhancement by marmoset Ly6 protein. Shows the potency of engineered AAV against HEK293T cells transfected with potential receptors. Extent of infection (max: 0.52, min: 0.05). Total brightness per signal area (max: 0.79, min: 0.17).

[0030] [Figure 11A-1] FIG. 11A shows non-limiting exemplary embodiments and data related to the performance of PHP.N, AAV9, and PHP.eB. In high dose CBA / J mice, PHP.N outperformed AAV9 and PHP.eB. Six to eight week old animals were injected retro-orbitally with 1×1012 v.g. of AAV9, PHP.eB, or PHP.N (n=3) packaged with CAG-mNeonGreen. Four weeks after injection, tissues were harvested and imaged to detect viral potency. Each data point in the mean pixel intensity quantification of the thalamus represents one animal, and the bars indicate the mean value. [Figure 11A-2] Same as above. [Figure 11B] Figure 11B shows non-limiting exemplary embodiments and data for quantifying AAV potency in WT and Car4-KO mice. The mean pixel intensity of whole brain sagittal sections and liver sections was quantified. Each individual data point was then normalized to the mean PHP.eB intensity. Each data point represents one animal, and the bar shows the mean value.

[0031] [Figure 12-1] Figure 12 shows non-limiting exemplary embodiments and data regarding enriched capsid variants during M-CREATE selection. Capsids were ranked according to their enrichment scores from round 1 and round 2 selection using M-CREATE Cre-dependent or Cre-independent recovery. Sequence frequency plots show the patterns of the most enriched variants from each round and selection type. [Figure 12-2] Same as above. [Figure 12-3] Same as above. [Figure 12-4] Same as above.

[0032] [Figure 13A]Figures 13A-D show non-limiting exemplary embodiments and data on snapshots of PHP.eB-Ly6a interactions obtained by the integrated structural modeling method. Figure 13A shows the workflow for modeling the engineered AAV receptor complex structure (PHP.eB: colored by pLDDT score, Ly6a: indicated by arrow). Figure 13B shows a comparison of the computationally modeled PHP.eB-Ly6a with the CryoEM structure of unbound PHP.eB (PDB ID: 7WQO). All high-confidence residues (pLDDT>45, see left panel arrow) in the inserted peptide showed consistent conformations between the two models, except for F6', which had no clear side chain density in the CryoEM map. The side chain of F6' predicted in the unbound PHP.eB model causes a steric clash in the predicted complex model. Figure 13C shows an assembled PHP.eB capsid-Ly6a model that represents an ensemble of all Ly6a binding states despite steric clashes that would arise in the cryo-EM particle reconstruction (PHP.eB: colored by pLDDT score, Ly6a: indicated by arrows). Top: cross-section of the assembled capsid model. Center: zoom in on the 3-fold spike, highlighting the steric clash between the three different binding states. Figure 13D shows an overlay structure of the computationally modeled PHP.eB-Ly6a (PHP.eB: rainbow) and PHP.eB-AAVR PKD2 cryoEM models (PDB ID: 7WQP). [Figure 13B] Same as above. [Figure 13C] Same as above. [Figure 13D] Same as above.

[0033] [Figure 14A-1]Figures 14A-B show non-limiting exemplary embodiments and data for modeling peptide complexes with Ly6c1 and mouse Car4. Figure 14A shows a comparison between computationally modeled PHP.C2-Ly6c1 binding poses predicted by AlphaFold-multimer v1 and v2. PHP.C2 peptides are colored by residue according to pLDDT score. Ly6c1 residues selected for mutation are shown as spheres. Also shown is the potency of PHP.C2 on HEK293T cells transfected with wild-type or mutant Ly6c1 receptors (Figure 14A (continued)). Extent of infection (max: 0.67, min: 0.13). Total brightness per signal area (max: 0.72, min: 0.31). Figure 14B shows the top five AlphaFold2 predicted mouse Car4-9P31 and Car4-9P36 peptide complex structures with 9P31 and 9P36 peptides colored by pLDDT score at each residue, and the potency of 9P31 and 9P36 for HEK293T cells transfected with wild-type or mutant Car4 receptors designed to disrupt putative site 2 binding. Extent of infection (top, max: 0.99, min: 0.12; bottom, max: 0.67, min: 0.13). Total brightness per signal area (top, max: 0.89, min: 0.33; bottom, max: 0.72, min: 0.31). [Figure 14A-2] Same as above. [Figure 14B-1] Same as above. [Figure 14B-2] Same as above. [Figure 14B-3] Same as above. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] Detailed Description In the following detailed description, reference is made to the accompanying drawings, which form a part of this specification. In the drawings, similar symbols typically identify similar components unless the context dictates otherwise. The exemplary embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized and other changes may be made without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described and illustrated in the figures herein, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are expressly contemplated and made part of the disclosure herein.

[0035] All patents, published patent applications, other publications, and sequences from GenBank and other databases mentioned herein are incorporated by reference in their entirety with respect to the relevant art.

[0036] Disclosed herein is a method for increasing the permeability of blood-brain barrier.In some embodiments, the method includes providing a targeting peptide that can bind to carbonic anhydrase IV, thereby increasing the permeability of blood-brain barrier.

[0037] Disclosed herein is a method for increasing the permeability of the blood-brain barrier.In some embodiments, the method comprises reducing carbonic anhydrase IV activity, thereby increasing the permeability of the blood-brain barrier.

[0038] Disclosed herein is a method for delivering a payload to the nervous system. In some embodiments, the method includes providing a targeting peptide capable of binding to carbonic anhydrase IV or a derivative thereof, the targeting peptide being part of a delivery system, the delivery system comprising a nucleic acid sequence to be delivered to the nervous system, and administering the delivery system to a subject. In some embodiments, the delivery system is an AAV vector. Also disclosed herein is a recombinant AAV (rAAV) vector comprising a targeting peptide having binding specificity for carbonic anhydrase IV.

[0039] Disclosed herein is an antibody or a fragment thereof. In some embodiments, the antibody or a fragment thereof comprises a peptide or a portion thereof having specificity for carbonic anhydrase IV. The antibody or a fragment thereof may comprise: (1) an amino acid sequence selected from SEQ ID NOs: 11-12 and SEQ ID NOs: 70-174; (2) an amino acid sequence having at least 80% sequence identity with an amino acid sequence selected from SEQ ID NOs: 11-12 and SEQ ID NOs: 70-174. Disclosed herein is an antibody conjugate comprising the antibody or a fragment thereof disclosed herein. In some embodiments, the antibody conjugate may further comprise a therapeutic agent or a detectable label. Disclosed herein is a peptide or a derivative or conjugate thereof having specificity for carbonic anhydrase IV. Disclosed herein is a nucleic acid comprising a sequence encoding the antibody or a fragment thereof or the peptide or a derivative or conjugate thereof disclosed herein.

[0040] Disclosed herein is a delivery system that includes (1) a targeting peptide having specificity for carbonic anhydrase IV, and (2) a pharmaceutical agent.

[0041] Disclosed herein are methods for designing targeting peptides with specificity for carbonic anhydrase IV. In some embodiments, the methods include: (1) targeting one or more positions functionally equivalent to S20, G21, W22, L36, W41, P42, E90, V111, Q112, H114, H139, V141, K143, F156, L217, T218, T219, P220, N221, D223, or W228 in carbonic anhydrase IV having an amino acid sequence of SEQ ID NO: 179; or (2) targeting one or more positions functionally equivalent to S20, G21, W22, L36, W41, P42, E90, V111, Q112, H114, H139, V141, K143, F156, L217, T218, T219, P220, N221, D223, or W228 in carbonic anhydrase IV having an amino acid sequence of SEQ ID NO: 180. The method includes generating in silico one or more targeting peptides capable of interacting with one or more positions functionally equivalent to S21, H22, W23, L37, W42, G43, M92, K113, Q114, H116, H141, V143, E145, Q158, L224, T225, T226, P227, T228, D231 or W236 in carbonic anhydrase IV having the sequence S21, S22, H22, W23, L37, W42, G43, M92, K113, Q114, H116, H141, V143, E145, Q158, L224, T225, T226, P227, T228, D231 or W236, respectively.

[0042] Disclosed herein is a method for increasing the permeability of blood-brain barrier in mouse species.In some embodiments, the method comprises providing a targeting peptide that can bind to Ly6c1, thereby increasing the permeability of blood-brain barrier in mouse species. definition

[0043] Unless otherwise defined, technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this disclosure belongs.See, for example, Singleton et al., Dictionary of Microbiology and Molecular Biology 2nd ed., J.Wiley&Sons (New York, NY1994); Sambrook et al., Molecular Cloning, A Laboratory Manual, Cold Spring Harbor Press (Cold Spring Harbor, NY1989).For the purpose of this disclosure, the following terms are defined below.

[0044] As used herein, the terms "nucleic acid" and "polynucleotide" are interchangeable and can refer to any nucleic acid, whether it is composed of phosphodiester bonds or modified bonds, such as phosphotriester, phosphoramidate, siloxane, carbonate, carboxymethylester, acetamidate, carbamate, thioether, bridged phosphoramidate, bridged methylene phosphonate, bridged phosphoramidate, bridged phosphoramidate, bridged methylene phosphonate, phosphorothioate, methylphosphonate, phosphorodithioate, bridged phosphorothioate or sultone bonds, and combinations of such bonds.The terms "nucleic acid" and "polynucleotide" also specifically include nucleic acids composed of bases other than the five biologically occurring bases (adenine, guanine, thymine, cytosine and uracil).

[0045] As used herein, the term "vector" can refer to a vehicle for carrying or transferring a nucleic acid. Non-limiting examples of vectors include plasmids and viruses (e.g., AAV viruses).

[0046] As used herein, the term "construct" can refer to a recombinant nucleic acid generated for the purpose of expressing a particular nucleotide sequence or used in the construction of other recombinant nucleotide sequences.

[0047] As used herein, the term "plasmid" can refer to a nucleic acid that can be used to replicate a recombinant DNA sequence in a host organism. The sequence can be double-stranded DNA.

[0048] The term "viral genome" refers to a nucleic acid sequence adjacent to a cis-acting nucleic acid sequence that mediates the packaging of nucleic acid into a viral capsid. In the case of AAV and parvovirus, for example, it is known that the "inverted terminal repeats" (ITRs) located at the 5' and 3' ends of the viral genome have this function, and that the ITRs can mediate the packaging of heterologous, e.g., non-wild type, viral genomes into viral capsids.

[0049] The term "element" can refer to a separate or distinct part of something, e.g., a nucleic acid sequence having a distinct function within a longer nucleic acid sequence. The terms "regulatory element" and "expression control element" are used interchangeably herein to refer to a nucleic acid molecule that can affect the expression of an operably linked coding sequence in a particular host organism. These terms are used broadly to encompass all elements that promote or regulate transcription, including promoters, core elements required for basic interaction of RNA polymerase with transcription factors, upstream elements, enhancers, and response elements (see, e.g., Lewin, "Genes V" (Oxford University Press, Oxford), pages 847-873). Exemplary regulatory elements in prokaryotes include promoters, operator sequences, and ribosome binding sites. Regulatory elements for use in eukaryotic cells may include, but are not limited to, transcriptional and translational control sequences, such as promoters, enhancers, splicing signals, polyadenylation signals, terminators, proteolytic signals, internal ribosome entry elements (IRES), 2A sequences, etc., that provide and / or regulate expression of a coding sequence and / or production of the encoded polypeptide in a host cell.

[0050] As used herein, the term "promoter" is a nucleotide sequence that allows binding of RNA polymerase and directs transcription of a gene. Typically, promoters are located in the 5' non-coding region of a gene, proximal to the transcription start site of the gene. Sequence elements within a promoter that function in initiating transcription are often characterized by consensus nucleotide sequences. Examples of promoters include, but are not limited to, promoters from bacteria, yeast, plants, viruses and mammals (including humans). Promoters can be inducible, repressible and / or constitutive. Inducible promoters initiate increased levels of transcription from DNA under their control in response to some change in culture conditions, such as a change in temperature.

[0051] As used herein, the term "enhancer" refers to a type of regulatory element that can increase the efficiency of transcription, regardless of the distance or orientation of the enhancer relative to the start site of transcription.

[0052] As used herein, the term "operably linked" is used to describe the connection between a regulatory element and a gene or its coding region. Typically, gene expression is placed under the control of one or more regulatory elements, such as, but not limited to, constitutive or inducible promoters, tissue-specific regulatory elements, and enhancers. A gene or coding region is said to be "operably linked" or "operably linked" or "operably associated" with a regulatory element, meaning that the gene or coding region is controlled or influenced by the regulatory element. For example, a promoter is operably linked to a coding sequence if the promoter affects the transcription or expression of the coding sequence.

[0053] As used herein, the term "polypeptide" is intended to encompass a single "polypeptide" as well as multiple "polypeptides" and refers to a molecule composed of monomers (amino acids) linearly linked by amide bonds (also known as peptide bonds). The term "polypeptide" refers to any or more chains of two or more amino acids and does not refer to a specific length of the product. Thus, peptide, dipeptide, tripeptide, oligopeptide, "protein," "amino acid chain," or any other term used to refer to a chain or chains of two or more amino acids are included within the definition of "polypeptide," and the term "polypeptide" may be used in place of or interchangeably with any of these terms. The term "polypeptide" is also intended to refer to the products of post-expression modifications of the polypeptide, including, but not limited to, glycosylation, acetylation, phosphorylation, amidation, derivatization with known protecting / blocking groups, proteolytic cleavage, or modification with non-naturally occurring amino acids. A polypeptide may be derived from a natural biological source or produced by recombinant technology, but is not necessarily translated from a specified nucleic acid sequence. It may be generated in any manner, including chemical synthesis.

[0054] As used herein, the term "variant" can refer to a polynucleotide or polypeptide that has a substantially similar sequence to a reference polynucleotide or polypeptide. In the case of a polynucleotide, a variant can have one or more nucleotide deletions, substitutions, and / or additions at the 5' end, 3' end, and / or one or more internal sites compared to the reference polynucleotide. The sequence similarity and / or difference between a variant and a reference polynucleotide can be detected using conventional techniques known in the art, such as polymerase chain reaction (PCR) and hybridization techniques. Variant polynucleotides also include synthetically derived polynucleotides, such as those generated by using site-directed mutagenesis. In general, variants of polynucleotides, including but not limited to DNA, can have at least about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, about 99% or more sequence identity with reference polynucleotides as determined by sequence alignment programs known to those skilled in the art. In the case of polypeptides, variants can have one or more of amino acid deletions, substitutions, additions compared to reference polypeptides. Similarity and / or difference in sequence between variants and reference polypeptides can be detected using conventional techniques known in the art, such as Western blot. Generally, a variant of a polypeptide can have at least about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, about 99% or more sequence identity to a reference polypeptide as determined by sequence alignment programs known to those of skill in the art.

[0055] As used herein, "sequence identity" or "identity" in the context of two nucleic acid or polypeptide sequences refers to the nucleotide bases or amino acid residues in the two sequences that are the same when aligned for maximum correspondence over a specified comparison window. When using percentages of sequence identity or similarity in the context of proteins, it is recognized that non-identical residue positions often differ by conservative amino acid substitutions, where amino acid residues are replaced with functionally equivalent residues of amino acid residues that have similar physicochemical properties, thus not changing the functional properties of the molecules.

[0056] A functionally equivalent residue of an amino acid as used herein can typically refer to other amino acid residues that have substantially similar physicochemical and stereochemical properties as the original amino acid. Physicochemical properties include water solubility (hydrophobic or hydrophilic), dielectric and electrochemical properties, physiological pH, partial charge of the side chain (positive, negative or neutral) and other properties identifiable to those skilled in the art. Stereochemical characteristics include the spatial and conformational arrangement of amino acids and their chirality. For example, glutamic acid is considered to be a functionally equivalent residue to aspartic acid in the sense of the present disclosure. Tyrosine and tryptophan are considered to be functionally equivalent residues to phenylalanine. Arginine and lysine are considered to be functionally equivalent residues to histidine.

[0057] As used herein, the term "binding" refers to a non-covalent interaction between macromolecules (e.g., between two proteins and / or peptides). During a non-covalent interaction, the macromolecules are said to "associate" or "interact" or "bind" (e.g., when molecule X is said to interact with molecule Y, it means that molecule X binds to molecule Y in a non-covalent manner). A binding interaction is characterized by a dissociation constant (Kd), e.g., 10 -6 M, 10 -7 M, 10 -8 M, 10 -9 M, 10 -10 M, 10 -11 M, 10 -12 M, 10-13 M, 10 -14 M, 10 -15 It can be characterized by a Kd of M or less, or a number or range between any two of these values. Kd can be dependent on environmental conditions, such as pH and temperature. "Affinity" refers to the strength of binding, with increased binding affinity being correlated with a lower Kd.

[0058] As used herein with respect to binding of a first molecule to a second molecule, the terms "specific," "specifically," or "specificity" refer to the recognition, contact, and formation of stable complexes between the first molecule and the second molecule, as well as substantially less or no recognition, contact, and formation of stable complexes between each of the first and second molecules and other molecules that may be present. Exemplary specific bindings are antibody-antigen interactions, cell receptor-ligand interactions, polynucleotide hybridization, enzyme-substrate interactions, and the like. As used herein with respect to molecular components of a complex, the term "specific" refers to the unique association of that component to the particular complex of which it is a part. As used herein with respect to sequences of polynucleotides, the term "specific" refers to the unique association of a sequence with a single polynucleotide that is a complementary sequence. By "stable complex" is meant a complex that is detectable and does not require any level of stability, although higher stability is generally preferred. As used herein with respect to the binding of a targeting peptide to carbonic anhydrase IV, the terms "specific," "specifically," or "specificity" refer to the ability of the targeting peptide to form a stable complex with carbonic anhydrase IV, with substantially little or no binding to macromolecules other than carbonic anhydrase IV that may be present. As used herein with respect to the binding of a targeting peptide to carbonic anhydrase IV, the terms "specific," "specifically," or "specificity" also refer to the ability of carbonic anhydrase IV to form a stable complex with the targeting peptide, with substantially little or no binding to candidate peptides other than the identified targeting peptide that may be present.

[0059] The term "AAV" or "adeno-associated virus" refers to the genus Dependoparvovirus within the Parvoviridae genus of viruses. For example, the AAV can be an AAV derived from a naturally occurring "wild-type" virus, an AAV derived from a rAAV genome packaged in a capsid derived from a capsid protein encoded by a naturally occurring cap gene, and / or an rAAV genome packaged in a capsid derived from a capsid protein encoded by a non-native capsid cap gene. Non-limiting examples of AAV include AAV type 1 (AAV1), AAV type 2 (AAV2), AAV type 3 (AAV3), AAV type 4 (AAV4), AAV type 5 (AAV5), AAV type 6 (AAV6), AAV type 7 (AAV7), AAV type 8 (AAV8), AAV type 9 (AAV9), AAV type 10 (AAV10), AAV type 11 (AAV11), AAV type 12 (AAV12), AAV type DJ (AAV-DJ), avian AAV, bovine AAV, canine AAV, equine AAV, primate AAV, non-primate AAV, and ovine AAV. In some examples, AAV is described as "primate AAV", which refers to AAV that infects primates. Similarly, AAV can infect bovine animals (such as "bovine AAV"). In some instances, the AAV is wild-type or naturally occurring, hi some instances, the AAV is recombinant.

[0060] As used herein, the term "AAV capsid" refers to the capsid protein or peptide of adeno-associated virus.In some instances, AAV capsid protein is configured to encapsidate genetic information (e.g., heterologous nucleic acid, transgene, therapeutic nucleic acid, viral genome).In some instances, the AAV capsid of the present disclosure is a variant AAV capsid, which means that in some instances, it is a parent or wild-type AAV capsid that is modified in the amino acid sequence of the parent AAV capsid protein.

[0061] As used herein, the term "AAV genome" can refer to a nucleic acid polynucleotide that encodes genetic information related to a virus. In some instances, the genome comprises a nucleic acid sequence adjacent to an AAV inverted terminal repeat (ITR) sequence. The AAV genome can be a rAAV genome generated using recombinant genetics methods, and can comprise a heterologous nucleic acid (e.g., a transgene) that includes and / or is adjacent to an ITR sequence.

[0062] The term "rAAV" refers to "recombinant AAV". In some embodiments, recombinant AAV has an AAV genome in which some or all of the rep and cap genes are replaced with heterologous sequences. The terms "AAV particle", "AAV nanoparticle", or "AAV vector", used interchangeably herein, refer to an AAV virus or virion that includes an AAV capsid in which a heterologous DNA polynucleotide or "genome" containing nucleic acid sequences flanking AAV (ITR sequences) is packaged. In some cases, the AAV particle is modified relative to the parent AAV particle.

[0063] The term "cap gene" refers to a nucleic acid sequence that encodes a capsid protein that forms or contributes to the formation of the viral capsid or protein shell. In the case of AAV, the capsid protein may be VP1, VP2 or VP3. In the case of other parvoviruses, the names and number of the capsid proteins may vary.

[0064] The term "rep genes" refers to nucleic acid sequences that encode the nonstructural proteins (rep78, rep68, rep52 and rep40) necessary for viral replication and production.

[0065] The terms "native" and "wild-type" are used interchangeably herein and can refer to a form of a polynucleotide, gene or polypeptide found in nature with its own regulatory sequences, if present.

[0066] As used herein, "endogenous" refers to the native form of a polynucleotide, gene, or polypeptide in its natural location within an organism or within the genome of an organism. An "endogenous polynucleotide" includes a native polynucleotide in its natural location within the genome of an organism. An "endogenous gene" includes a native gene in its natural location within the genome of an organism. An "endogenous polypeptide" includes a native polypeptide in its natural location within an organism.

[0067] As used herein, "heterologous" refers to a polynucleotide, gene, or polypeptide that is not normally found in the host organism, but is introduced into the host organism. A "heterologous polynucleotide" includes a native coding region, or a portion thereof, that is reintroduced into the source organism in a form that differs from the corresponding native polynucleotide. A "heterologous gene" includes a native coding region, or a portion thereof, that is reintroduced into the source organism in a form that differs from the corresponding native gene. For example, a heterologous gene may include a native coding region that is part of a chimeric gene that includes a non-native regulatory region that is reintroduced into the native host. A "heterologous polypeptide" includes a native polypeptide that is reintroduced into the source organism in a form that differs from the corresponding native polypeptide. Genes and proteins of interest can be fused to other genes and proteins to produce chimeric or fusion proteins. Genes and proteins useful according to embodiments of the present disclosure include not only the full-length sequences specifically exemplified, but also portions, segments, and / or fragments of these sequences, variants, mutants, chimeras, and fusions thereof, including contiguous fragments and internal and / or terminal deletions compared to the full-length molecule.

[0068] As used herein, the term "exogenous" gene is meant to encompass any gene that does not naturally occur in the genome of an individual. For example, miRNAs can be exogenously introduced by viruses, such as AAV nanoparticles.

[0069] As used herein, "antibody" or "antigen-binding polypeptide" refers to a polypeptide or polypeptide complex that specifically recognizes and binds to an antigen. An antibody can be a whole antibody and any antigen-binding fragment or single chain thereof. Thus, the term "antibody" includes any protein or peptide-containing molecule that contains at least a portion of an immunoglobulin molecule that has biological activity of binding to an antigen. Examples of such include, but are not limited to, at least a portion of a heavy or light chain complementarity determining region (CDR) or ligand-binding portion thereof, a heavy or light chain variable region, a heavy or light chain constant region, a framework (FR) region or any portion thereof, or a binding protein.

[0070] As used herein, the term "antibody fragment" or "antigen-binding fragment" refers to a portion of an antibody, such as F(ab')2, F(ab)2, Fab', Fab, Fv, scFv, etc. Regardless of structure, an antibody fragment binds with the same antigen recognized by the intact antibody. The term "antibody fragment" includes aptamers, spiegelmers, and diabodies. The term "antibody fragment" also includes any synthetic or genetically engineered protein that acts like an antibody by binding to a specific antigen to form a complex.

[0071] As used herein, "subject" refers to an animal that is the object of treatment, observation, or experiment. "Animals" include cold-blooded and warm-blooded vertebrates and invertebrates, such as fish, crustaceans, reptiles, and especially mammals. As used herein, "mammal" refers to an individual belonging to the class Mammalia, including but not limited to humans, farm animals and livestock, zoo animals, sports animals, and pet animals. Non-limiting examples of mammals include mice; rats; rabbits; guinea pigs; dogs; cats; sheep; goats; cows; horses; primates, such as monkeys, chimpanzees, and apes, and especially humans. In some embodiments, the mammal is a human. However, in some embodiments, the mammal is not a human. In some embodiments, the subject is a rodent (e.g., a rat or a mouse). In some embodiments, the subject is a primate (e.g., a human or a monkey (money)).

[0072] As used herein, the term "treatment" refers to an intervention made in response to a disease, disorder, or physiological symptoms exhibited by a patient. The purpose of treatment may include, but is not limited to, one or more of alleviating or preventing symptoms, slowing or halting the progression or worsening of a disease, disorder, or symptom, and remission of a disease, disorder, or symptom. The terms "treat" and "treatment" include, for example, therapeutic treatment, prophylactic treatment, and applications in which a subject reduces the risk of developing a disorder or other risk factor. Treatment does not require a complete cure of the disorder, but encompasses embodiments in which symptoms or underlying risk factors are alleviated. In some embodiments, "treatment" refers to both therapeutic treatment and preventative or prophylactic measures. Those in need of treatment include those already suffering from a disease or disorder or an undesirable physiological symptom, as well as those in whom a disease or disorder or an undesirable physiological symptom is to be prevented. As used herein, the term "prevention" refers to any activity that reduces the burden on individuals who subsequently develop those symptoms. This can be done at the primary, secondary and / or tertiary prevention levels, where a) primary prevention avoids the onset of symptoms / disorders / symptoms; b) secondary prevention activities are directed at the early stages of the treatment of symptoms / disorders / symptoms, thereby increasing the chances of intervention to prevent the progression of symptoms / disorders / symptoms and the appearance of symptoms; and c) tertiary prevention reduces the adverse effects of already established symptoms / disorders / symptoms, for example, by restoring function and / or reducing any symptoms / disorders / symptoms or associated complications. The term "prevent" does not require 100% elimination of the possibility of an event. Rather, it indicates that the possibility of the occurrence of an event is reduced in the presence of a compound or method.

[0073] As used herein, the term "effective amount" refers to an amount sufficient to effect beneficial or desired biological and / or clinical results.

[0074] As used herein, the term "pharmaceutical acceptable" carrier is non-toxic to cells or mammals exposed at the dosage and concentration used. "Pharmaceutical acceptable" carriers can be organic or inorganic solid or liquid excipients suitable for the selected mode of application, such as, but not limited to, oral application or injection, and can be administered in the form of conventional pharmaceutical preparations, such as solids such as tablets, granules, powders, capsules, and liquids such as solutions, emulsions, suspensions, and the like. In many cases, physiologically acceptable carriers are aqueous pH buffers, such as phosphate buffers or citrate buffers. Physiologically acceptable carriers may also include one or more of antioxidants including ascorbic acid, low molecular weight (less than about 10 residues) polypeptides, proteins such as serum albumin, gelatin, immunoglobulins, hydrophilic polymers such as polyvinylpyrrolidone, amino acids, carbohydrates including glucose, mannose or dextrin, chelating agents such as EDTA, sugar alcohols such as mannitol or sorbitol, salt-forming counterions such as sodium, and non-ionic surfactants such as, for example, Tween™, polyethylene glycol (PEG), and Pluronics™. Auxiliaries, stabilizers, emulsifiers, lubricants, binders, pH adjusters, isotonicity agents, and other conventional additives may also be added to the carrier.

[0075] The blood-brain barrier (BBB) ​​presents a major challenge to delivering large molecules to the central nervous system (CNS), in part because of the paucity of effective targets for BBB crossing, the identification of which is a critical first step in drug development.

[0076] Disclosed herein is a novel receptor (e.g., carbonic anhydrase IV) on the BBB interface for enhancing BBB crossing, and related methods of using it to increase the permeability of the BBB and deliver agents to the nervous system (e.g., CNS). Also disclosed herein is a targeting peptide or derivative thereof that can bind to the BBB-crossing receptor (e.g., carbonic anhydrase IV) disclosed herein, and a recombinant AAV vector, an antibody or fragment thereof, a peptide or derivative thereof that includes the targeting peptide or derivative thereof. Also disclosed herein is a method of designing a targeting peptide with binding specificity for carbonic anhydrase IV. Structural insights from the identification and computational modeling of carbonic anhydrase IV provide new routes to human brain-permeable chemicals (drugs) and biological substances (including gene delivery). Receptors for enhanced blood-brain barrier crossing

[0077] The blood-brain barrier (BBB) ​​has emerged as a complex, dynamic, adaptable interface that controls the exchange of substances between the central nervous system (CNS) and blood to prevent uncontrolled leakage of substances from the blood into the brain. The cells that make up the structure of the BBB include mainly brain endothelial cells, which constantly communicate with other cells of the CNS (e.g., astrocytes, microglia, neurons, mast cells and pericytes, as well as circulating immune cells), adapting their behavior to serve the needs of the CNS, responding to pathological symptoms, and in some cases participating in the development, maintenance or progression of diseases. The complexity of BBB function explains much of the difficulty in developing drugs that can cross the BBB. By utilizing receptors on the BBB interface, a method can be provided to cross the BBB.

[0078] Disclosed herein is a novel receptor on the BBB interface and its use to enhance BBB crossing and CNS efficacy, such as increasing the permeability of the BBB and delivering therapeutic agents across the BBB to the nervous system. In some embodiments, the receptor for enhancing BBB crossing is carbonic anhydrase IV. In some embodiments, the BBB-crossing receptor is Ly6c1. Without being bound by any theory, the novel target receptor disclosed herein may facilitate enhanced BBB receptor-mediated transcytosis across various species, including mammals such as humans.

[0079] In some embodiments, the method of increasing the permeability of the BBB includes providing a targeting peptide capable of binding to a BBB-crossing receptor (e.g., carbonic anhydrase IV or lymphocyte antigen 6 complex, locus C1 (Ly6c1)), thereby increasing the permeability of the BBB (e.g., via transcytosis). In some embodiments, the activity of at least one of the BBB-crossing receptors (e.g., carbonic anhydrase IV or Ly6c1) can be reduced through binding to the targeting peptide. Thus, in some embodiments, the method of increasing the permeability of the BBB includes reducing the activity of carbonic anhydrase IV or Ly6c1, thereby increasing the permeability of the BBB. In some embodiments, the targeting peptide binds to one or more of the zinc-binding site (e.g., catalytic pocket) and the substrate-binding site of carbonic anhydrase IV. The carbonic anhydrase IV can be a vertebrate carbonic anhydrase IV, including non-human primates and humans. In some embodiments, the carbonic anhydrase IV is mouse carbonic anhydrase IV (Car4), human carbonic anhydrase IV (CA4), or a variant or homolog thereof. In some embodiments, the targeting peptide binds to Ly6c1 in the mouse species, thereby increasing the permeability of the blood-brain barrier in the mouse species. Carbonic anhydrase IV

[0080] In some embodiments, a trans-BBB receptor disclosed herein that can facilitate delivery of pharmaceutical agents across the BBB is carbonic anhydrase IV. Carbonic anhydrase IV is an isozyme that belongs to the carbonic anhydrase family (a family of zinc metalloenzymes), [ka] The enzyme catalyzes the reversible hydration reaction of CO2, H2 and CO2 inside and outside the cell. + , and HCO3 - Carbonic anhydrase is involved in a variety of biological processes, including respiration, mineralization, acid-base balance, bone resorption, and the formation of aqueous humor, cerebrospinal fluid, saliva, and gastric acid. Carbonic anhydrases exhibit extensive diversity in tissue distribution and their subcellular localization. There are at least seven genetically distinct isoenzymes of mammalian carbonic anhydrase, designated I–VII, each of which catalyzes the reversible hydration of carbon dioxide by a zinc hydroxide mechanism. Physiological functions regulated by carbonic anhydrase include, for example, the production of HCO in the lungs by respiration. 3- Elimination of HCO in the kidney 3- These include the recycling of blood, the production of aqueous humor in the eye, cerebrospinal fluid in the brain, the production of gastric juice in the stomach, pancreatic juice, and bone resorption by osteoclasts. Members of the carbonic anhydrase family also play important roles in metabolic processes including urea formation, gluconeogenesis, and lipogenesis.

[0081] Unlike other carbonic anhydrases that are soluble or bound to the plasma membrane by transmembrane domains, carbonic anhydrase IV is a glycosylphosphatidylinositol-anchored membrane isoenzyme. Carbonic anhydrase IV is widely conserved across vertebrates and has a similar CNS expression profile in humans, with recent single-cell analysis of human cerebral vasculature confirming expression in CA4 in the human BBB. Carbonic anhydrase IV has been shown to regulate pH, which is associated with neuronal discharge and may affect neuronal function via ion-gated channels.

[0082] In some embodiments, the carbonic anhydrase IV disclosed herein is human carbonic anhydrase IV (CA4). CA4 is known to be localized to the luminal surface of brain endothelial cells throughout the cortex and cerebellum, where it enzymatically regulates carbon dioxide-bicarbonate balance. Human CA4 is "highly active" in CO2 hydration and HCO3 - It has been previously characterized as a 35-kDa protein with higher activity than other isozymes in catalyzing the dehydration of . In general, human CA4 contains a 260-amino acid "CA domain" that includes an 18-amino acid signal sequence at the N-terminus of the protein for endoplasmic reticulum (ER) translocation and active site amino acid residues that show 30-36% homology with cytoplasmic CA. At the C-terminus, a further 27 amino acid residues containing a 21-amino acid hydrophobic sequence sufficient to span the membrane are preceded by a 6-amino acid signal sequence for GPI anchoring. Amino acid residue Ser266 was identified as the attachment site for the GPI anchor. Removal of the C-terminal hydrophobic domain found in the CA4 precursor has important effects on the realization of GPI anchoring, cell surface expression, and enzymatic activity. Based on the amino acid sequence deduced from the nucleotide sequence, human CA4 does not contain the classical consensus site (Asn-Xxx-Ser / Thr) for N-glycosylation. Human CA4 also does not contain oligosaccharide chains, whereas other mammalian carbonic anhydrase IVs (eg, mouse carbonic anhydrase IV (Car4)) are glycoproteins with one to several oligosaccharide side chains.

[0083] In some embodiments, the carbonic anhydrase IV disclosed herein is mouse carbonic anhydrase IV (Car4). Car4 was recently found to be among the mouse proteins that most strongly positively correlate with plasma protein uptake in the brain (slightly stronger than the frequently targeted transferrin receptor). This property is useful for identifying receptors with enhanced BBB crossing. Car4 is also expressed in the GI tract, kidneys and lungs, as well as taste receptor cells that allow for sensing of carbonation. Mouse Car4 and human CA4 are highly homologous, containing the same amino acids at positions important for enzymatic activity (e.g., histidine residue 64 (His64)), with some differences including, for example, that mouse Car4 is an N-linked glycoprotein and the rate of CO2 hydration catalyzed by mouse Car4 is much lower than human CA4. Without being bound by any theory, the lower enzymatic activity of mouse Car4 may be related to the substitution of Gly63 of human CA4 with Gln63, among several other amino acid substitutions. Another difference between mouse Car4 and human CA4 is the Val-131-Asp-136 segment (segment 130), which forms an α-helix in mouse Car4 and an extended loop in human CA4.

[0084] In some embodiments, the carbonic anhydrase IV (Car4) disclosed herein as a receptor for enhancing BBB crossing can be any carbonic anhydrase IV, such as mouse Car4, human CA4, or their homologs or variants. Carbonic anhydrase IV homologs and / or variants can be derived from vertebrate species, including but not limited to mouse, rat, human, cow, rabbit, monkey, pig, horse, rainbow trout, chimpanzee, squirrel, chicken, goat and sheep. Carbonic anhydrase IV homologs from various species can be found in public databases identifiable to those skilled in the art, including, for example, UniProt, NCBI and Swiss-Prot.

[0085] In some embodiments, mouse Car4 disclosed herein as a receptor for enhancing BBB crossing comprises a sequence having SEQ ID NO: 179. In some embodiments, human CA4 disclosed herein as a receptor for enhancing BBB crossing comprises a sequence having SEQ ID NO: 180. In some embodiments, a receptor disclosed herein for enhancing BBB crossing is a carbonic anhydrase IV homolog or variant of human CA4 (e.g., SEQ ID NO: 180) or mouse Car4 (SEQ ID NO: 179). Carbonic anhydrase IV homologs and variants can be nearly identical to the sequence of SEQ ID NO: 179 or SEQ ID NO: 180, or at least 50% (e.g., 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100%, 102%, 104%, 105%, 106%, 107%, 108%, 109%, 109, 109, 108, 109, 109, 109, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 12 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100%, or a number or range between any two of these values).

[0086] In some embodiments, the targeting peptide can bind to a carbonic anhydrase IV (e.g., mouse Car4, human CA4, or a homolog or variant thereof) disclosed herein, thereby increasing the permeability of the BBB (e.g., via transcytosis). In some embodiments, increasing the permeability of the BBB is achieved by altering (e.g., increasing or decreasing) carbonic anhydrase IV activity, e.g., decreasing its activity.

[0087] In some embodiments, modification of carbonic anhydrase IV activity is achieved by binding of a targeting peptide to one or more active sites of carbonic anhydrase IV, including the zinc binding site and the hydrophobic substrate binding pocket. For example, the targeting peptide can bind to the zinc binding site, the hydrophobic substrate binding pocket, or both.

[0088] The zinc-binding site in carbonic anhydrase IV has a conserved structure dominated by a β-sheet superstructure with a metal-binding site formed by at least three His residues. Without being bound by any theory, the zinc-binding site is believed to be on one face of the β-sheet at the bottom of a 15-Å deep conical active site cleft where zinc is liganded by three His residues and a hydroxide ion with tetrahedral geometry. A hydrophobic substrate-binding pocket is adjacent to the zinc-binding hydroxide and is formed in large part by bulky residues such as Val at its base and Val, Trp, and Leu at its neck. This pocket is highly conserved among all active isozymes based on phylogenetic comparisons. Without being bound by any theory, the hydrophobic pocket is believed to have a minimum width and depth for efficient catalysis, and linear free energy relationships indicate that the volume of the amino acid residues at the base of the pocket and the hydrophobicity of the residues at the neck of the pocket are important for activity. Both the zinc-binding site and the hydrophobic substrate-binding pocket are highly conserved among carbonic anhydrase isozymes.

[0089] The targeting peptide can bind to one or more conserved amino acid residues at the interaction site of carbonic anhydrase IV. In some embodiments, computational modeling methods (e.g., Alphafold2 multimer) can be used to predict peptide interaction sites (e.g., AAV interaction sites, if the peptide is part of the AAV capsid) on carbonic anhydrase IV (e.g., mouse Car4). Table 1 provides a list of Alphafold2 multimer predicted AAV interaction sites on mouse carbonic anhydrase IV and the corresponding residues in human CA4. [Table 1-1] [Table 1-2]

[0090] In some embodiments, the targeting peptide can interact with one or more positions functionally equivalent to S20, G21, W22, L36, W41, P42, E90, V111, Q112, H114, H139, V141, K143, F156, L217, T218, T219, P220, N221, D223 or W228 in carbonic anhydrase IV having the amino acid sequence of SEQ ID NO:179. In some embodiments, the target peptide can interact with one or more positions functionally equivalent to S21, H22, W23, L37, W42, G43, M92, K113, Q114, H116, H141, V143, E145, Q158, L224, T225, T226, P227, T228, D231 or W236 in carbonic anhydrase IV having the amino acid sequence of SEQ ID NO: 180. Lymphocyte antigen 6

[0091] In some embodiments, the BBB-crossing receptor disclosed herein that can enhance BBB crossing upon binding to a targeting peptide in mouse species is lymphocyte antigen 6 complex, locus C1 (Ly6c1). Ly6c1 is a glycosylphosphatidylinositol-anchored (GPI-anchored) protein and belongs to the Ly6 family of GPI-anchored surface glycoproteins. Known as lymphocyte antigen 6 or urokinase-type plasminogen activator receptor, Ly6 is a family of closely related mouse glycoproteins that share a common structure but differ in their tissue expression patterns and functions. Ly6 family proteins are structurally related proteins characterized by the LU domain, an 80 amino acid domain that contains 10 cysteines arranged in a specific spacing pattern that allows for distinct disulfide bridges that form a three-finger structural motif. Ly6c1 can be used as a novel receptor that serves as a powerful research tool in mice, including, for example, using directed evolution in combination with in silico design to design enhanced AAV capsids against Ly6c1.

[0092] In some embodiments, the Ly6c1 receptor disclosed herein as a receptor for enhanced BBB crossing can be mouse Ly6c1 or a homolog or variant thereof. In some embodiments, the Ly6c1 receptor of Mus musculus has the amino acid sequence of SEQ ID NO: 293 (Uniprot accession: P0CW02). In some embodiments, the Ly6c1 receptor disclosed herein for enhanced BBB crossing has an amino acid sequence similar to that of SEQ ID NO: 293 by about or at least 50% (e.g., 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68% or more) of the sequence of SEQ ID NO: 293. , 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100%, or a number or range between any two of these values).

[0093] In some embodiments, the targeting peptide can bind to Ly6c1 as disclosed herein, thereby increasing the permeability of the BBB in mouse species. The mouse species can be selected from species of the family Muridae, subfamily Murinae, genus Mus and / or subgenus Mus. Targeting peptides and in silico screening

[0094] Methods of using the receptors described herein to increase the permeability of the BBB and deliver pharmaceutical agents across the BBB to the nervous system include providing a targeting peptide capable of binding to a BBB-crossing receptor disclosed herein (e.g., Ly6c1 or carbonic anhydrase IV) or having binding specificity for a BBB-crossing receptor (e.g., Ly6c1 or carbonic anhydrase IV such as Car4 and CA4). Carbonic anhydrase IV targeting peptides

[0095] In some embodiments, the method includes providing to a subject a targeting peptide capable of binding to carbonic anhydrase IV or a targeting peptide that has binding specificity for carbonic anhydrase IV (e.g., Car4 and CA4).

[0096] The targeting peptide can bind to the zinc binding site and / or hydrophobic substrate binding pocket of carbonic anhydrase IV as described above, thereby altering the activity of carbonic anhydrase IV (e.g., decreasing carbonic anhydrase IV activity). The length of the targeting peptide can be about, at least or at most 4-15 (e.g., 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15) amino acids in length.

[0097] The targeting peptide may include: (1) an amino acid sequence selected from SEQ ID NOs: 11-12 and SEQ ID NOs: 70-174; (2) an amino acid sequence having at least 80% sequence identity (e.g., 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100%, or a number or range between any two of these values) to an amino acid sequence selected from SEQ ID NOs: 11-12 and SEQ ID NOs: 70-174.

[0098] The targeting peptide may comprise an amino acid sequence selected from SEQ ID NOs: 70 to 108. The targeting peptide may comprise an amino acid sequence selected from SEQ ID NOs: 70 to 86. The targeting peptide may comprise an amino acid sequence selected from AKPTPLLGLLQAQTG (SEQ ID NO: 70), AKPTPLLLLLQAQTG (SEQ ID NO: 71), AQPPLGGLLAQAQTG (SEQ ID NO: 72), AKPPGPWAEAQAQTG (SEQ ID NO: 73), or AQPPLLGGLAQAQTG (SEQ ID NO: 74). In some embodiments, the targeting peptide comprises an amino acid sequence having at least 80% (e.g., 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100%, or a number or range between any two of these values) sequence identity to an amino acid sequence selected from SEQ ID NOs: 70-74.

[0099] The targeting peptide may comprise at least 4 consecutive amino acids from the sequence AKPTPLLGLLQAQTG (SEQ ID NO: 70). For example, the targeting peptide may comprise the sequence KPTP (SEQ ID NO: 181), PTPL (SEQ ID NO: 182), TPLL (SEQ ID NO: 183), PLLG (SEQ ID NO: 184), LLGL (SEQ ID NO: 185), LGLL (SEQ ID NO: 186) or GLLQ (SEQ ID NO: 187). The targeting peptide may comprise at least 5 consecutive amino acids from the sequence AKPTPLLGLLQAQTG (SEQ ID NO: 70). For example, the targeting peptide may comprise the sequence KPTPL (SEQ ID NO: 188), PTPLL (SEQ ID NO: 189), TPLLG (SEQ ID NO: 190), PLLGL (SEQ ID NO: 191), LLGLL (SEQ ID NO: 192) or LGLLQ (SEQ ID NO: 193). The targeting peptide may comprise at least 6 consecutive amino acids from the sequence AKPTPLLGLLQAQTG (SEQ ID NO: 70). For example, the targeting peptide may comprise the sequence of KPTPLL (SEQ ID NO: 194), PTPLLG (SEQ ID NO: 195), TPLLGL (SEQ ID NO: 196), PLLGLL (SEQ ID NO: 197) or LLGLLQ (SEQ ID NO: 198). The targeting peptide may comprise at least 7 consecutive amino acids from the sequence of AKPTPLLGLLQAQTG (SEQ ID NO: 70). For example, the targeting peptide may comprise the sequence of KPTPLLG (SEQ ID NO: 199), PTPLLGL (SEQ ID NO: 200), TPLLGLL (SEQ ID NO: 201) or PLLGLLQ (SEQ ID NO: 202). The targeting peptide may comprise at least 8 consecutive amino acids from the sequence of AKPTPLLGLLQAQTG (SEQ ID NO: 70). For example, the targeting peptide may comprise the sequence of KPTPLLGL (SEQ ID NO: 203), PTPLLGLL (SEQ ID NO: 204) or TPLLGLLQ (SEQ ID NO: 205). The targeting peptide may comprise at least 9 consecutive amino acids from the sequence of AKPTPLLGLLQAQTG (SEQ ID NO: 70). For example, the targeting peptide may comprise the sequence of KPTPLLGLL (SEQ ID NO: 206) or PTPLLGLLQ (SEQ ID NO: 207). In some embodiments, the targeting peptide comprises AKPTPLLGLLQAQTG (SEQ ID NO: 70).

[0100] The targeting peptide may comprise at least 4 consecutive amino acids from the sequence AKPTPLLLLLQAQTG (SEQ ID NO: 71). For example, the targeting peptide may comprise the sequence KPTP (SEQ ID NO: 181), PTPL (SEQ ID NO: 182), TPLL (SEQ ID NO: 183), PLLL (SEQ ID NO: 208), LLLL (SEQ ID NO: 209) or LLLQ (SEQ ID NO: 210). The targeting peptide may comprise at least 5 consecutive amino acids from the sequence AKPTPLLLLLQAQTG (SEQ ID NO: 71). For example, the targeting peptide may comprise the sequence KPTPL (SEQ ID NO: 188), PTPLL (SEQ ID NO: 189), TPLLL (SEQ ID NO: 211), PLLLL (SEQ ID NO: 212), LLLLL (SEQ ID NO: 213) or LLLLQ (SEQ ID NO: 214). The targeting peptide may comprise at least 6 consecutive amino acids from the sequence AKPTPLLLLLQAQTG (SEQ ID NO: 71). For example, the targeting peptide may comprise the sequence of KPTPLL (SEQ ID NO: 194), PTPLLL (SEQ ID NO: 215), TPLLLL (SEQ ID NO: 216), PLLLLL (SEQ ID NO: 217) or LLLLLQ (SEQ ID NO: 218). The targeting peptide may comprise at least 7 consecutive amino acids from the sequence of AKPTPLLLLLQAQTG (SEQ ID NO: 71). For example, the targeting peptide may comprise the sequence of KPTPLLL (SEQ ID NO: 219), PTPLLLL (SEQ ID NO: 220), TPLLLLL (SEQ ID NO: 221) or PLLLLLQ (SEQ ID NO: 222). The targeting peptide may comprise at least 8 consecutive amino acids from the sequence of AKPTPLLLLLQAQTG (SEQ ID NO: 71). For example, the targeting peptide may comprise the sequence of KPTPLLLL (SEQ ID NO: 223), PTPLLLLL (SEQ ID NO: 224) or TPLLLLLQ (SEQ ID NO: 225). The targeting peptide may comprise at least 9 consecutive amino acids from the sequence of AKPTPLLLLLQAQTG (SEQ ID NO: 71). For example, the targeting peptide may comprise the sequence of KPTPLLLLL (SEQ ID NO: 226) or PTPLLLLLQ (SEQ ID NO: 227). In some embodiments, the targeting peptide comprises AKPTPLLLLLQAQTG (SEQ ID NO: 71).

[0101] The targeting peptide may comprise at least 4 consecutive amino acids from the sequence AQPPLGGLLAQAQTG (SEQ ID NO: 72). For example, the targeting peptide may comprise the sequence PPLG (SEQ ID NO: 228), PLGG (SEQ ID NO: 229), LGGL (SEQ ID NO: 230), GGLL (SEQ ID NO: 231), GLLA (SEQ ID NO: 232) or LLAQ (SEQ ID NO: 233). The targeting peptide may comprise at least 5 consecutive amino acids from the sequence AQPPLGGLLAQAQTG (SEQ ID NO: 72). For example, the targeting peptide may comprise the sequence PPLGG (SEQ ID NO: 234), PLGGL (SEQ ID NO: 235), LGGLL (SEQ ID NO: 236), GGLLA (SEQ ID NO: 237) or GLLAQ (SEQ ID NO: 238). The targeting peptide may comprise at least 6 consecutive amino acids from the sequence AQPPLGGLLAQAQTG (SEQ ID NO: 72). For example, the targeting peptide may comprise the sequence of PPLGGL (SEQ ID NO: 239), PLGGLL (SEQ ID NO: 240), LGGLLA (SEQ ID NO: 241), or GGLLAQ (SEQ ID NO: 242). The targeting peptide may comprise at least 7 consecutive amino acids from the sequence of AQPPLGGLLAQAQTG (SEQ ID NO: 72). For example, the targeting peptide may comprise the sequence of PPLGGLL (SEQ ID NO: 243), PLGGLLA (SEQ ID NO: 244), or LGGLLAQ (SEQ ID NO: 245). The targeting peptide may comprise at least 8 consecutive amino acids from the sequence of AQPPLGGLLAQAQTG (SEQ ID NO: 72). For example, the targeting peptide may comprise the sequence of PPLGGLLA (SEQ ID NO: 246) or PLGGLLAQ (SEQ ID NO: 247). In some embodiments, the targeting peptide comprises AQPPLGGLLAQAQTG (SEQ ID NO: 72).

[0102] The targeting peptide may comprise at least 4 consecutive amino acids from the sequence AKPPGPWAEAQAQTG (SEQ ID NO: 73). For example, the targeting peptide may comprise the sequence KPPG (SEQ ID NO: 248), PPGP (SEQ ID NO: 249), PGPW (SEQ ID NO: 250), GPWA (SEQ ID NO: 251), PWAE (SEQ ID NO: 252), WAEA (SEQ ID NO: 253), or AEAQ (SEQ ID NO: 254). The targeting peptide may comprise at least 5 consecutive amino acids from the sequence AKPPGPWAEAQAQTG (SEQ ID NO: 73). For example, the targeting peptide may comprise the sequence KPPGP (SEQ ID NO: 255), PPGPW (SEQ ID NO: 256), PGPWA (SEQ ID NO: 257), GPWAE (SEQ ID NO: 258), PWAEA (SEQ ID NO: 259), or WAEAQ (SEQ ID NO: 260). The targeting peptide may comprise at least 6 consecutive amino acids from the sequence AKPPGPWAEAQAQTG (SEQ ID NO: 73). For example, the targeting peptide may comprise the sequence of KPPGPW (SEQ ID NO: 261), PPGPWA (SEQ ID NO: 262), PGPWAE (SEQ ID NO: 263), GPWAEA (SEQ ID NO: 264) or PWAEAQ (SEQ ID NO: 265). The targeting peptide may comprise at least 7 consecutive amino acids from the sequence of AKPPGPWAEAQAQTG (SEQ ID NO: 73). For example, the targeting peptide may comprise the sequence of KPPGPWA (SEQ ID NO: 266), PPGPWAE (SEQ ID NO: 267), PGPWAEA (SEQ ID NO: 268) or GPWAEAQ (SEQ ID NO: 269). The targeting peptide may comprise at least 8 consecutive amino acids from the sequence of AKPPGPWAEAQAQTG (SEQ ID NO: 73). For example, the targeting peptide may comprise the sequence of KPPGPWAE (SEQ ID NO: 270), PPGPWAEA (SEQ ID NO: 271) or PGPWAEAQ (SEQ ID NO: 272). The targeting peptide may comprise at least 9 consecutive amino acids from the sequence of AKPPGPWAEAQAQTG (SEQ ID NO: 73). For example, the targeting peptide may comprise the sequence of KPPGPWAEA (SEQ ID NO: 273) or PPGPWAEAQ (SEQ ID NO: 274). In some embodiments, the targeting peptide comprises AKPPGPWAEAQAQTG (SEQ ID NO: 73).

[0103] The targeting peptide may comprise at least 4 consecutive amino acids from the sequence AQPPLLGGLAQAQTG (SEQ ID NO: 74). For example, the targeting peptide may comprise the sequence PPLL (SEQ ID NO: 275), PLLG (SEQ ID NO: 184), LLGG (SEQ ID NO: 276), LGGL (SEQ ID NO: 230), GGLA (SEQ ID NO: 277) or GLAQ (SEQ ID NO: 278). The targeting peptide may comprise at least 5 consecutive amino acids from the sequence AQPPLLGGLAQAQTG (SEQ ID NO: 74). For example, the targeting peptide may comprise the sequence PPLLG (SEQ ID NO: 279), PLLGG (SEQ ID NO: 280), LLGGL (SEQ ID NO: 281), LGGLA (SEQ ID NO: 282) or GGLAQ (SEQ ID NO: 283). The targeting peptide may comprise at least 6 consecutive amino acids from the sequence AQPPLLGGLAQAQTG (SEQ ID NO: 74). For example, the targeting peptide may comprise the sequence of PPLLGG (SEQ ID NO: 284), PLLGGL (SEQ ID NO: 285), LLGGLA (SEQ ID NO: 286), or LGGLAQ (SEQ ID NO: 287). The targeting peptide may comprise at least 7 consecutive amino acids from the sequence of AQPPLLGGLAQAQTG (SEQ ID NO: 74). For example, the targeting peptide may comprise the sequence of PPLLGGL (SEQ ID NO: 288), PLLGGLA (SEQ ID NO: 289), or LLGGLAQ (SEQ ID NO: 290). The targeting peptide may comprise at least 8 consecutive amino acids from the sequence of AQPPLLGGLAQAQTG (SEQ ID NO: 74). For example, the targeting peptide may comprise the sequence of PPLLGGLA (SEQ ID NO: 291) or PLLGGLAQ (SEQ ID NO: 292). In some embodiments, the targeting peptide comprises AQPPLLGGLAQAQTG (SEQ ID NO: 74). Targeting peptides for Ly6c1

[0104] In some embodiments, the method includes providing a targeting peptide capable of binding to Ly6c1 or having binding specificity for Ly6c1 in a subject (eg, a mouse).

[0105] The targeting peptide is selected from 1) an amino acid sequence selected from AQFVVGQSYAQ (SEQ ID NO: 6), AQRYQGDSVAQ (SEQ ID NO: 7), AQWSTNAGYAQ (SEQ ID NO: 8), AQERVGFAQAQ (SEQ ID NO: 9), AQWMTHGSAAQ (SEQ ID NO: 10), AQWPTSYDAAQ (SEQ ID NO: 11), DGSSSYYDAAQ (SEQ ID NO: 12), AQGENPGRWAQ (SEQ ID NO: 13), DGTGQVTGWAQ (SEQ ID NO: 14), DGTGSTTGWAQ (SEQ ID NO: 15), and SPRYKGDSVAQ (SEQ ID NO: 57); or (2) AQFVVG The amino acid sequence may include an amino acid sequence having at least 80% sequence identity to an amino acid sequence selected from QSYAQ (SEQ ID NO: 6), AQRYQGDSVAQ (SEQ ID NO: 7), AQWSTNAGYAQ (SEQ ID NO: 8), AQERVGFAQAQ (SEQ ID NO: 9), AQWMTHGSAAQ (SEQ ID NO: 10), AQWPTSYDAAQ (SEQ ID NO: 11), DGSSSYYDAAQ (SEQ ID NO: 12), AQGENPGRWAQ (SEQ ID NO: 13), DGTGQVTGWAQ (SEQ ID NO: 14), DGTGSTTGWAQ (SEQ ID NO: 15), and SPRYKGDSVAQ (SEQ ID NO: 57).

[0106] In some embodiments, the targeting peptide comprises the amino acid sequence of SPRYKGDSVAQ (SEQ ID NO:57) or an amino acid sequence having at least (e.g., 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100%, or a number or range between any two of these values) sequence identity to SPRYKGDSVAQ (SEQ ID NO:57). In silico screening of targeting peptides

[0107] Disclosed herein are methods for designing targeting peptides with binding specificity for carbonic anhydrase IV. In some embodiments, the methods include: (1) targeting one or more positions functionally equivalent to S20, G21, W22, L36, W41, P42, E90, V111, Q112, H114, H139, V141, K143, F156, L217, T218, T219, P220, N221, D223, or W228 in carbonic anhydrase IV having an amino acid sequence of SEQ ID NO: 179; or (2) targeting one or more positions functionally equivalent to S20, G21, W22, L36, W41, P42, E90, V111, Q112, H114, H139, V141, K143, F156, L217, T218, T219, P220, N221, D223, or W228 in carbonic anhydrase IV having an amino acid sequence of SEQ ID NO: 180. The method includes generating in silico one or more targeting peptides capable of interacting with one or more positions functionally equivalent to S21, H22, W23, L37, W42, G43, M92, K113, Q114, H116, H141, V143, E145, Q158, L224, T225, T226, P227, T228, D231 or W236 in carbonic anhydrase IV having the sequence S21, S22, H22, W23, L37, W42, G43, M92, K113, Q114, H116, H141, V143, E145, Q158, L224, T225, T226, P227, T228, D231 or W236, respectively.

[0108] In some embodiments, generating one or more targeting peptides in silico includes generating a plurality of candidate peptides in silico and performing a computer-assisted docking simulation for each of the plurality of candidate peptides that bind to carbonic anhydrase IV, and (1) detecting one or more positions functionally equivalent to S20, G21, W22, L36, W41, P42, E90, V111, Q112, H114, H139, V141, K143, F156, L217, T218, T219, P220, N221, D223, or W228 in carbonic anhydrase IV having an amino acid sequence of SEQ ID NO: 179; or (2) analyzing the molecular structure of carbonic anhydrase IV bound to one or more candidate peptides to identify one or more targeting peptides capable of interacting with one or more positions functionally equivalent to S21, H22, W23, L37, W42, G43, M92, K113, Q114, H116, H141, V143, E145, Q158, L224, T225, T226, P227, T228, D231 or W236 in carbonic anhydrase IV having the amino acid sequence of SEQ ID NO: 180.

[0109] In silico methods can provide a high-throughput approach to screen a large number of candidate peptides and identify targeting peptides with desired specificity. In some embodiments, the candidate peptides can include a portion of an AAV capsid protein. In some embodiments, the candidate peptides are a portion of an AAV capsid protein. The method can include constructing one or more peptide receptor models for each candidate peptide complexed with carbonic anhydrase IV (e.g., performing computer-assisted docking simulations). Molecular models can be constructed for peptide-protein complexes using any rational computational peptide design and docking methods, databases, programs, or algorithms described herein or known in the art. Exemplary computational modeling methods, public databases and programs include AlphaFold (e.g., AlphaFold2 and AlphaFold-Multimer provided by DeepMind, available at github.com / deepmind / alphafold), RoseTTAFold (github.com / RosettaCommons / RoseTTAFold), AutoDock, DOCK, FlexX, GOLD, OSPREY, SCWRL, PyMol, SWISS-MODEL (academic.oup.com / nar / article / 46 / Wl / W296 / 5000024), Protein Data Examples of such libraries include, but are not limited to, the Protein Database (PDB) (available via the websites of member organizations, e.g., PDBe-pdbe.org, PDBj-pdbj.org, RCSB-rcsb.org / pdb, and BMRB-bmrb.wisc.edu), Phyre2 (nature.com / articles / nprot.2015.053), and RaptorX (nature.com / articles / nprot.2012.085).

[0110] The method may further include evaluating features or parameters associated with the interaction between the candidate peptide and carbonic anhydrase IV using visualization software such as PyMol, Qlucore Omics Explorer, WebMol, Insight II, Discovery Studio2.1, and others identifiable to those skilled in the art. The features or parameters evaluated may include interfacial energy and physical and geometric scoring. Evaluating features or parameters associated with the interaction between the candidate peptide and carbonic anhydrase IV may include measuring surface complementarity, solvent accessible surface area, solvation free energy, electrostatic interaction energy, van der Waals energy, and / or total molecular mechanics energy. The method may also include determining the total number of atoms at the interface, the total number of atoms of the peptide that are in clash with carbonic anhydrase IV, the bond angle of the peptide, and / or the bond depth of the peptide in each putative peptide-receptor complex model. The method may also include identifying the lowest energy conformation of the peptide-carbonic anhydrase IV complex. The energy score of each conformation can be determined by calculating the interaction energy between the peptide and carbonic anhydrase IV, including electrostatic energy, desolvation energy, and van der Waals energy, as will be understood by one of skill in the art.

[0111] In some embodiments, targeting peptides can be assigned binding scores and ranked based on binding scores.A threshold can be imposed to identify desired targeting peptides.The method can include obtaining binding scores for each of a plurality of candidate peptides that bind to carbonic anhydrase IV, and selecting one or more of the plurality of candidate peptides that have binding scores that exceed a threshold as the targeting peptides that have binding specificity (or high binding affinity) to carbonic anhydrase IV.

[0112] A combination of physical and geometric scoring parameters, including calculation of interface energy, bond angle, and binding pocket depth, can be used to generate a binding score. In some embodiments, the binding score for each of a plurality of candidate peptide sequences is obtained by (1) counting the total number of atoms at the interface between the candidate peptide and carbonic anhydrase IV, (2) counting the total number of atoms in the candidate peptide that are in collision with carbonic anhydrase IV, (3) obtaining the bond angle of the candidate peptide, and / or (4) obtaining the binding depth of the candidate peptide.

[0113] The total number of interface atoms between the candidate peptide and carbonic anhydrase may be the total number of atoms within a cutoff distance between the interface atoms of the candidate peptide and the interface atoms of carbonic anhydrase. The cutoff distance may vary in different embodiments. In some embodiments, the cutoff distance is up to about 5 angstroms (e.g., 2 angstroms, 3 angstroms, 4 angstroms, or 5 angstroms). The number of interface atoms between the candidate peptide and carbonic anhydrase IV may vary in different embodiments. For example, the number of interface atoms can be about, or at least, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 45, 50, or a number or range between any of these values.

[0114] The total number of atoms in the peptide that collide with carbonic anhydrase IV can be the total number of atoms within the collision distance. The collision distance can be defined as the distance at which a geometric collision occurs between a peptide atom and a receptor atom. In some embodiments, the collision distance can be about 1 angstrom.

[0115] The bond angle of a peptide can be defined as the angle between the vector from the center of mass of carbonic anhydrase IV to the anchor of carbonic anhydrase IV and the vector from the center of mass of carbonic anhydrase to the center of mass of the peptide.

[0116] The binding depth can be defined as the difference in distance between the closest point on the peptide to the center of carbonic anhydrase IV and the minor axis of the ellipsoid shell of carbonic anhydrase IV normalized by the minor axis.

[0117] The binding score may be the sum of the contact score, which is calculated based on the total number of atoms in the interface between the candidate peptide and carbonic anhydrase and the total number of colliding atoms, the bond angle and the bond depth. In some embodiments, the binding score is 0 or greater. For example, the binding score is defined as 0 if the sum of the contact score, the bond angle and the bond depth is negative. The binding score of a targeting peptide that binds to carbonic anhydrase IV can be about 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 110, 120, 128, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, or a number or range between any two of these values.

[0118] In some embodiments, the candidate peptide

number

number

[0119] The method may further include selecting one or more candidate peptides having a binding score above a threshold as a targeting peptide having binding specificity for carbonic anhydrase IV. The threshold may be any value defined by a user. In some embodiments, the threshold may be a binding score of a targeting peptide known to have binding specificity for carbonic anhydrase IV. In some embodiments, the results from the individual pairwise competitions (relative scores between two competing peptides) may be assembled into a peptide competition metric that ranks the set of candidate peptides according to their receptor binding probability encoded in the AlphaFold2 neural network.

[0120] Table 2 provides an exemplary list of targeting peptides ranked by Automated Pairwise Peptide Receptor Analysis for Screening Engineered AAV (APPRAISE-AAV), the details of which are described in Examples 1 and 3 of this disclosure. B_POI in Table 2 is the binding score of each peptide of interest. The peptide sequences in Table 2 are the amino acid sequences that start at AAV9 residue A587 and end at residue G594. [Table 2-1] [Table 2-2] [Table 2-3] Antibody and Peptide Derivatives

[0121] Also disclosed herein are antibodies or fragments thereof comprising an amino acid sequence having binding specificity for a cross-BBB receptor (e.g., carbonic anhydrase IV or Ly6c1) disclosed herein. Also disclosed herein are peptide derivatives or conjugates thereof having specificity for a cross-BBB receptor (e.g., carbonic anhydrase IV or Ly6c1) disclosed herein.

[0122] In some embodiments, the antibody or fragment thereof can further comprise an Fc domain. In some embodiments, the antibody or fragment thereof is a single chain variable fragment (scFv), a single domain antibody, an immunoglobulin molecule, a monoclonal antibody, a chimeric antibody, a CDR-grafted antibody, a humanized antibody, a Fab fragment, a Fab' fragment, a F(ab')2 fragment, an Fv fragment, a disulfide-linked Fv, an scFv, a single domain antibody, a diabody, a multispecific antibody, a bispecific antibody, an anti-idiotypic antibody, a bispecific antibody, or a functionally active epitope-binding fragment thereof.

[0123] In some embodiments, the antibody or fragment thereof is a bispecific antibody comprising at least one Fab with specificity for carbonic anhydrase IV. Bispecific antibodies can comprise separate binding sites directed against different antigens.

[0124] In some embodiments, the antibody or fragment thereof disclosed herein can comprise an amino acid sequence selected from SEQ ID NOs: 11 to 12 and SEQ ID NOs: 70 to 174, or (2) an amino acid sequence having at least 80% sequence identity to an amino acid sequence selected from SEQ ID NOs: 11 to 12 and SEQ ID NOs: 70 to 174. In some embodiments, the antibody or fragment thereof disclosed herein can comprise an amino acid sequence selected from SEQ ID NOs: 6 to 15 and 57, or (2) an amino acid sequence having at least 80% sequence identity to an amino acid sequence selected from SEQ ID NOs: 6 to 15 and 57.

[0125] In some embodiments, the antibody or its fragment cannot induce a harmful immune response in the subject to be treated, such as a human. In some embodiments, the antibody, its fragment, variant or derivative of the present disclosure is modified to reduce their immunogenicity using art-recognized techniques. For example, the antibody can be a humanized antibody, a primatized antibody, a deimmunized antibody or a chimeric antibody.

[0126] In some embodiments, the antibody, fragment, variant, or derivative thereof may further comprise a chemical moiety that is not naturally associated with the antibody. For example, the antibody or fragment thereof may comprise a flexible linker or may be modified to add a functional moiety such as a detectable label. The antibody, fragment, variant, or derivative thereof may be modified such that the attachment does not interfere with or prevent the antibody from binding to its epitope, i.e., by covalent or non-covalent attachment of the chemical moiety to the antibody. In some embodiments, the chemical moiety may be conjugated to the antibody using any technique known in the art.

[0127] The present disclosure also provides isolated polynucleotides or nucleic acid molecules that code for the peptides, antibodies, fragments, variants or derivatives of the present disclosure.For example, the polynucleotides of the present disclosure can code for the heavy chain variable region and the light chain variable region of an antibody, its fragment, variant or derivative on the same polynucleotide molecule or on separate polynucleotide molecules.In some embodiments, the polynucleotides of the present disclosure can code for a part of the heavy chain variable region and the light chain variable region of an antibody (e.g., CDR region), its fragment, variant or derivative on the same polynucleotide molecule or on separate polynucleotide molecules. Payload delivery across the BBB

[0128] Disclosed herein are methods and delivery systems for delivering a payload (e.g., a therapeutic agent) to the nervous system. In some embodiments, the method includes providing a targeting peptide that can bind to carbonic anhydrase IV or a derivative thereof. The targeting peptide can be part of a delivery system, and the delivery system can include the payload that is delivered to the nervous system. The method can further include administering the delivery system to a subject.

[0129] In some embodiments, the delivery system comprises nanoparticles, nanotubes, nanowires, dendrimers, liposomes, ethosomes and aquasomes, polymersomes and niosomes, foams, hydrogels, cubosomes, quantum dots, exosomes, macrophages, and combinations thereof. In some embodiments, the delivery system comprises nanoparticles selected from lipid-based nanoparticles, polymeric nanoparticles, inorganic nanoparticles, surfactant-based emulsions, nanowires, silica nanoparticles, virus-like particles, peptide or protein-based particles, lipid-polymer particles, nanolipoprotein particles, and combinations thereof.

[0130] In some embodiments, the delivery system comprises a viral vector or a non-viral vector.For example, the viral vector can comprise an adenoviral vector, an adeno-associated viral (AAV) vector, a lentiviral vector, or a retroviral vector.In some embodiments, the viral vector is an AAV vector, and the target peptide can be part of the capsid protein of the AAV vector. Adeno-associated virus (AAV) and recombinant AAV (rAAV)

[0131] In some embodiments, the delivery system for delivering payload across the BBB is an AAV vector. AAV is a replication-deficient parvovirus, whose single-stranded DNA genome is approximately 4.7 kb long, including 145 nucleotide inverted terminal repeats (ITRs). The ITRs play a role in the integration of AAV DNA into the host cell genome. When AAV infects a host cell, the viral genome is integrated into the host's chromosome, resulting in latent infection of the cell. In natural systems, helper viruses (e.g., adenoviruses or herpes viruses) provide genes that allow the production of AAV virus in infected cells. In the case of adenovirus, genes E1A, E1B, E2A, E4 and VA provide helper functions. Upon infection with the helper virus, the AAV provirus is rescued and amplified, and both AAV and adenovirus are produced. In the case of recombinant AAV vectors that do not have Rep and / or Cap genes, AAV can be non-integrating.

[0132] In some embodiments, AAV vector can comprise the coding region of one or more proteins of interest.AAV vector can comprise 5'AAV ITR, 3'AAV ITR, promoter and restriction site downstream of promoter to allow insertion of polynucleotide encoding one or more proteins of interest, promoter and restriction site are located downstream of 5'AAV ITR and upstream of 3'AAV ITR.In some embodiments, AAV vector comprises post-transcriptional regulator element downstream of restriction site and upstream of 3'AAV ITR.

[0133] Viral vectors can include additional sequences that make the vector suitable for replication and integration in eukaryotes.In other embodiments, the viral vectors disclosed herein can include shuttle elements that make the vector suitable for replication and integration in both prokaryotes and eukaryotes.In some embodiments, viral vectors can include additional transcription and translation initiation sequences, such as promoters and enhancers, and additional transcription and translation terminators, such as polyadenylation signals.Various regulatory elements that can be included in AAV vectors are described in US Patent Application Publication No. 2012 / 0232133, which is incorporated herein by reference in its entirety.

[0134] The AAV serotype used to derive the AAV capsid protein may vary. The AAV capsid may be derived from AAV9 or a variant thereof. The AAV capsid may be derived from an AAV selected from AAV1, AAV2, AAV3, AAV3b, AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, AAV10, human isolate hu.31, human isolate hu.32, rhesus isolate rh.8, and rhesus isolate rh.10. In some embodiments, the AAV capsid protein is selected from AAV9, AAV9 K449R (or K449R AAV9), AAV1, AAVrhlO, AAV-DJ, AAV-DJ8, AAV5, AAVPHP.B(PHP.B), AAVPHP.A(PHP.A), AAVG2B-26, AAVG2B-13, AAVTH1.1-32, AAVTH1.1-35, AAVPHP.B2(PH P.B2), AAVPHP.B3(PHP.B3), AAVPHP.N / PHP.B-DGT, AAVPHP.B-EST, AAVPHP.B-GGT, AAVPHP.B-ATP, AAVPHP.B-ATT-T, AAVPHP.B-DGT-T, AAVPHP.B-GGT-T, A AVPHP.B-SGS, AAVPHP.B-AQP, AAVPHP.B-QQP, AAVPHP.B-SNP(3), AAVPHP.B-SNP, AAVPHP.B-QGT, AAVPHP.B-NQT, AAVPHP.B-EGS, AAVPHP.B-SGN, AAVPHP.B- EGT, AAVPHP.B-DST, AAVPHP.B-DST, AAVPHP.B-STP, AAVPHP.B-PQP, AAVPHP.B-SQP, AAVPHP.B-QLP, AAVPHP.B-TMP, AAVPHP.B-TTP, AAVPHP.S / G2A12, AAVG2 Al 5 / G2A3(G2A3), AAVG2B4(G2B4), AAVG2B5(G2B5), PHP.S, AAV2, AAV2G9, AAV3, AAV3a, AAV3b, AAV3-3, AAV4, AAV4-4, AAV6, AAV6.1, A AV6.2, AAV6.1.2, AAV7, AAV7.2, AAV8, AAV9.11, AAV9.13, AAV9.16, AAV9.24, AAV9.45, AAV9.47, AAV9.61, AAV9.68, AAV9.84, AAV9.9、AAV10、AAV11、AAV12、AAV16.3、AAV24.1、AAV27.3、AAV42.12、AAV42-1b、AAV42-2、AAV42-3a、AAV42-3b、AAV42-4、AAV42-5a、AAV42- 5b、AAV42-6b、AAV42-8、AAV42-10、AAV42-11、AAV42-12、AAV42-13、AAV42-15、AAV42-aa、AAV43-1、AAV43-12、AAV43-20、AAV43-21、AAV 43-23、AAV43-25、AAV43-5、AAV44.1、AAV44.2、AAV44.5、AAV223.1、AAV223.2、AAV223.4、AAV223.5、AAV223.6、AAV223.7、AAVl-7 / rh.48、AAVl-8 / rh.49、AAV2-l5 / rh.62、AAV2-3 / rh.6l、AAV2-4 / rh.50、AAV2-5 / rh.5l、AAV3.l / hu.6、AAV3.l / hu.9、AAV3-9 / rh.52、AAV3-1 l / rh.53、AAV4-8 / r11.64、AAV4-9 / rh.54、AAV4-l9 / rh.55、AAV5-3 / rh.57、AAV5-22 / rh.58、AAV7.3 / hu.7、AAVl6.8 / hu.10、AAVl6.l2 / hu.1 1、AAV29.3 / bb.1、AAV29.5 / bb.2、AAVl06.l / hu.37、AAV1 l4.3 / hu.40、AAVl27.2 / hu.4l、AAVl27.5 / hu.42、AAVl28.3 / hu.44、AAVl30.4 / hu.48、AAVl45.l / hu.53、AAVl45.5 / hu.54、AAVl45.6 / hu.55、AAVl6l.l0 / hu.60、AAVl6l.6 / hu.6l、AAV33.l2 / hu.l7、AAV33.4 / hu.l5、AAV33.8 / hu.l6、AAV52 / hu.l9、AAV52.l / hu.20、AAV58.2 / hu.25、AAVA3.3、AAVA3.4、AAVA3.5、AAVA3.7、AAVC1、AAVC2、AAVC5、AAVF3、AAVF5、AAVH2、AAVrh.72、AAVhu.8、AAVrh.68、AAVrh.70、AAVpi.1、AAVpi.3、AAVpi.2、AAVrh.60、AAVrh.44、AAVrh.65、AAVrh.55、AAVrh.47、AAVrh.69、AAVrh.45、AAVrh.59、AAVhu.12、AAVH6、AAVH-1 / hu.1、AAVH-5 / hu.3、AAVLG-l0 / rh.40、AAVLG-4 / rh.38、AAVLG-9 / hu.39、AAVN72l-8 / rh.43、AAVCh.5、AAVCh.5Rl、AAVcy.2、AAVcy.3、AAVcy.4、AAVcy.5、AAVCy.5R1、AAVCy.5R2、AAVCy.5R3、AAVCy.5R4、AAVcy.6、AAVhu.1、AAVhu. 2、AAVhu.3、AAVhu.4、AAVhu.5、AAVhu.6、AAVhu.7、AAVhu.9、AAVhu.10、AAVhu.11、AAVhu.13、AAVhu.15、AAVhu.l6、AAVhu.17、AAVhu.18、AAVhu.20、AAVhu. Vhu.21、AAVhu.22、AAVhu.23.2、AAVhu.24、AAVhu.25、AAVhu.27、AAVhu.28、AAVhu.29、AAVhu.29R、AAVhu.31、AAVhu.32、AAVhu.34、AAVhu.35、AAVhu.3 7、AAVhu.39、AAVhu.40、AAVhu.41、AAVhu.42、AAVhu.43、AAVhu.44、AAVhu.44Rl、AAVhu.44R2、AAVhu.44R3、AAVhu.45、AAVhu.46、AAVhu.47、AAVhu.48 、AAVhu.48Rl、AAVhu.48R2、AAVhu.48R3、AAVhu.49、AAVhu.51、AAVhu.52、AAVhu.54、AAVhu.55、AAVhu.56、AAVhu.57、AAVhu.58、AAVhu.60、AAVhu.61、AAVhu. AVhu.63、AAVhu.64、AAVhu.66、AAVhu.67、AAVhu.14 / 9、AAVhu.t19、AAVrh.2、AAVrh.2R、AAVrh.8、AAVrh.8R、AAVrh.10、AAVrh.12、AAVrh.13、AAVrh.13 R、AAVrh.14、AAVrh.17、AAVrh.18、AAVrh.19、AAVrh.20、AAVrh.21、AAVrh.22、AAVrh.23、AAVrh.24、AAVrh.25、AAVrh.31、AAVrh.32、AAVrh.33、AAVrh.34、AAVrh.35、AAVrh.36、AAVrh.37、AAVrh.37R2、AAVrh.38、AAVrh.39、AAVrh.40、AAVrh.46、AAVrh.48、AAVrh.48.1、AAVrh.48.1.2、AAVrh.48.2、AAVrh.49、AAVrh.5 1、AAVrh.52、AAVrh.53、AAVrh.54、AAVrh.56、AAVrh.57、AAVrh.58、AAVrh.6l、AAVrh.64、AAVrh.64R1、AAVrh.64R2、AAVrh.67、AAVrh.73、AAVrh.74、AAVrh.8、AAVrh.8、AAVrh. A586R mutation、AAVrh8R R533 A mutation、AAAV、BAAV、ヤギ AAV、ウシ AAV、AAVhE1.1、AAVhEr1.5、AAVhER1.14、AAVhEr1.8、AAVhEr1.16、AAVhEr1.18、AAVhErl.35、AAVhEr1.7、AAVhEr1 .36、AAVhEr2.29、AAVhEr2.4、AAVhEr2.16、AAVhEr2.30、AAVhEr2.31、AAVhEr2.36、AAVhERl.23、AAVhEr3.1、AAV2.5T, AAV-PAEC, AAV-LK01, AAV-LK02, AAV-LK03, AAV-LK04, AAV-LK05, AAV-LK06, AAV-LK07, AAV-LK08, AAV-LK09, AAV-LK10, AAV-LK11, AAV-LK12, AAV-LK13, AAV-LK14, AAV-LK15, AAV-LK16, AAV-LK17, AAV-LK18, AAV-LK19, AAV-PAEC2, AAV-PAEC4, AAV-PAEC6, AAV-PAEC7, AAV-PAEC8, AAV-PAEC11, AAV-PAEC12, AAV-2-pre-miRNA-101, AAV-8h, AAV-8b, AAV-h, AAV-b, AAV SM10-2, AAV Shuffle100-1, AAV Shuffle100-3, AAV Shuffle100-7, AAV Shuffle10-2, AAV Shuffle10-6, AAV Shuffle10-8, AAV Shuffle100-2, AAV SM10-1, AAV SM10-8, AAV SM100-3, AAV SM100-10, BNP61 AAV, BNP62 AAV, BNP63 AAV, AAVrh.50, AAVrh.43, AAVrh.62, AAVrh.48, AAVhu.19, AAVhu.11, AAVhu.53, AAV4-8 / rh.64, AAVLG-9 / hu.39, AAV54.5 / hu.23, AAV54.2 / hu.22, AAV54.7 / hu.24, AAV54.1 / hu.21, AAV54.4R / hu.27, AAV46.2 / hu.28, AAV46.6 / hu.29, AAV128.1 / hu.43, authentic AAV (ttAAV), EGRENN AAV10, Japanese AAV10 serotype, AAV CBr-7.1, AAV CBr-7.10, AAV CBr-7.2, AAV CBr-7.3, AAV CBr-7.4, AAV CBr-7.5, AAV CBr-7.7, AAV CBr-7.8, AAV CBr-B7.3, AAV CBr-B7.4、AAV CBr-El、AAV CBr-E2、AAV CBr-E3、AAV CBr-E4、AAV CBr-E5、AAV CBr-e5、AAV CBr-E6、AAV CBr-E7、AAV CBr-E8、AAV CHt-1、AAV CHt-2、AAV CHt-3、AAV CHt-6.1、AAV CHt-6.1、AAV CHt-6.5、AAV CHt-6.6、AAV CHt-6.7、AAV CHt-6.8、AAV CHt-P1、AAV CHt-P2、AAV CHt-P5、AAV CHt-P6、AAV CHt-P8、AAV CHt-P9、AAV CKd-1、AAV CKd-10、AAV CKd-2、AAV CKd-3、AAV CKd-4、AAV CKd-6、AAV CKd-7、AAV CKd-8、AAV CKd-Bl、AAV CKd-B2、AAV CKd-B3、AAV CKd-B4、AAV CKd-B5、AAV CKd-B6、AAV CKd-B7、AAV CKd-B8、AAV CKd-H1、AAV CKd-H2、AAV CKd-H3、AAV CKd-H4、AAV CKd-H5、AAV CKd-H6、AAV CKd-N3、AAV CKd-N4、AAV CKd-N9、AAV CLg-F1、AAV CLg-F2、AAV CLg-F3、AAV CLg-F4、AAV CLg-F5、AAV CLg-F6、AAV CLg-F7、AAV CLg-F8、AAV CLv-1、AAV CLvl-l、AAV Clvl-lO、AAV CLvl-2、AAV CLvl-l2、AAV CLvl-3、AAV CLv-13、AAV CLvl-4、AAV Clvl-7、AAV Clvl-8、AAV Clvl-9、AAV. An AAV serotype selected from CLv-2, AAV CLv-3, AAV CLv-4, AAV CLv-6, AAV CLv-8, AAV CLv-D1, AAV CLv-D2, AAV CLv-D3, AAV CLv-D4, AAV CLv-D5, AAV CLv-D6, AAV CLv-D7, AAV CLv-D8, AAV CLv-El, AAV CLv-Kl, AAV CLv-K3, AAV CLv-K6, AAV CLv-L4, AAV CLv-L5, AAV CLv-L6, AAV CLv-M1, AAV CLv-M11, AAV CLv-M2, AAV CLv-M5, AAV CLv-M6, AAV CLv-M7, AAV CLv-M8, AAV CLv-M9, AAV CLv-R1, AAV CLv-R2, AAV CLv-R3, AAV CLv-R4, AAV CLv-R5, AAV CLv-R6, AAV CLv-R7, AAV CLv-R8, AAV CLv-R9, AAV CSp-l, AAV CSp-lO, AAV CSp-11, AAV CSp-2, AAV CSp-3, AAV CSp-4, AAV CSp-6, AAV CSp-7, AAV CSp-8, AAV CSp-8.l0, AAV CSp-8.2, AAV CSp-8.4, AAV CSp-8.5, AAV CSp-8.6, AAV CSp-8.7, AAV CSp-8.8, AAV CSp-8.9, AAV CSp-9, AAV.hu.48R3, AAV.VR-355, AAV3B, AAV4, AAV5, AAVF1 / HSC1, AAVF11 / HSC11, AAVF12 / HSC12, AAVF13 / HSC13, AAVF14 / HSC14, AAVF15 / HSC15, AAVF16 / HSC16, AAVF17 / HSC17, AAVF2 / HSC2, AAVF3 / HSC3, AAVF4 / HSC4, AAVF5 / HSC5, AAVF6 / HSC6, AAVF7 / HSC7, AAVF8 / HSC8, AAVF9 / HSC9, variants thereof, hybrids or chimeras of any of the aforementioned AAV serotypes, or any combination thereof.

[0135] The AAV vector can be an AAV9 having an amino acid sequence of SEQ ID NO:178, or an amino acid sequence having at least 70% sequence identity (e.g., at least 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99% or more) to the amino acid sequence of SEQ ID NO:178.

[0136] In some embodiments, the AAV vector disclosed herein can be used as an AAV transfer vector carrying a transgene encoding a protein of interest (e.g., a targeting peptide) to produce a recombinant AAV virus capable of expressing the protein of interest in a host cell.Therefore, recombinant AAV virus (rAAV) is also disclosed herein.rAAV can include the AAV capsid protein described herein.

[0137] rAAV can include chimeric AAV capsids. "Chimeric" AAV capsids refer to capsids with exogenous amino acids or amino acid sequences. rAAV can include mosaic AAV capsids. "Mosaic" AAV capsids refer to capsids composed of two or more capsid proteins or polypeptides, each of which is derived from a different AAV serotype. rAAV can be the result of capsid conversion, which in some cases refers to the packaging of inverted terminal repeats (ITRs) from a first serotype into a capsid of a second serotype, where the first and second serotypes are not the same. In some cases, the capsid genes of the parent AAV serotype van are pseudotyped, which means that the ITRs from a first AAV serotype (e.g., AAV1) are used in a capsid from a second AAV serotype (e.g., AAV9), where the first and second AAV serotypes are not the same. As a non-limiting example, a pseudotyped AAV serotype containing AAV1 ITRs and AAV9 capsid proteins may be designated as AAV1 / 9. rAAV may additionally or alternatively contain a capsid engineered to express an exogenous ligand-binding moiety (e.g., a receptor), or a modified native receptor.

[0138] In some embodiments, the rAAV capsid protein comprises one or more amino acid substitutions or insertions in the amino acid sequence of the AAV capsid protein. The rAAV capsid protein described herein optionally has an insertion or substitution of an amino acid that is heterologous to the wild-type AAV capsid protein at the amino acid position of the insertion or substitution. In some embodiments, the amino acid is not endogenous to the wild-type AAV capsid protein at the amino acid position of the insertion or substitution. The amino acid may be a naturally occurring amino acid at the same or equivalent amino acid position as the insertion of the substitution into a different AAV capsid protein. The AAV capsid protein from which the engineered AAV capsid protein of the present disclosure is produced can be referred to as the "parent" or "wild-type" AAV capsid protein, or the "corresponding unmodified capsid protein". In some cases, the parent AAV capsid protein has a serotype selected from AAV1, AAV2, rAAV3, AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, AAV10, AAV11, and AAV12.The complete genome of AAV-1 is provided under GenBank accession number NC_002077; the complete genome of AAV-2 is provided under GenBank accession number NC_001401 and Srivastava et al., J. Virol., 45:555-564 (1983); the complete genome of AAV-3 is provided under GenBank accession number NC_1829; the complete genome of AAV-4 is provided under GenBank accession number NC_001829; the AAV-5 genome is provided under GenBank accession number AF085716; the complete genome of AAV-6 is provided under GenBank accession number NC_00 1862; at least portions of the AAV-7 and AAV-8 genomes are provided in GenBank accession numbers AX753246 and AX753249, respectively; the AAV-9 genome is provided in Gao et al., J. Virol., 78:6381-6388 (2004); the AAV-10 genome is provided in Mol. Ther., 13(1):67-76 (2006); the AAV-11 genome is provided in Virology, 330(2):375-383 (2004); a portion of the AAV-12 genome is provided in Genbank accession number DQ813647; a portion of the AAV-13 genome is provided in Genbank accession number EU285562. At least a portion of the AAV-DJ genome is provided in Grimm, D. et al., J. Virol. 82, 5887-5911 (2008).

[0139] In some embodiments, the rAAV vector disclosed herein can have a transgene encoding a targeting peptide described herein that can bind to carbonic anhydrase IV or has specificity for carbonic anhydrase IV (e.g., Car4 or CA4). The targeting peptide can be part of the capsid of the rAAV. Also disclosed herein are AAV capsid proteins. The AAV capsid proteins can include the targeting peptides disclosed herein.

[0140] The location of the targeting peptide within the capsid protein may vary. In some embodiments, the targeting peptide can be inserted between two adjacent amino acids in AA586-595 of the AAV9 capsid protein (e.g., between AA586 and AA587, between AA587 and AA588, between AA588 and AA589, between AA589 and AA590, between AA590 and AA591, between AA591 and AA592, between AA592 and AA593, between AA593, between AA594 and AA595) or its functional equivalent in other AAV capsid proteins. The AAV vector may be a vector selected from AAV1, AAV2, AAV3, AAV3b, AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, AAV10, AAV-DJ, human isolate hu.31, human isolate hu.32, rhesus isolate rh.8, rhesus isolate rh.10, or variants. In some embodiments, the AAV vector is AAV9 or a variant or derivative thereof. For example, the AAV capsid protein comprises or consists of SEQ ID NO:178 or an amino acid sequence at least 80% (e.g., 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100%, or a number or range between any two of these values) identical to SEQ ID NO:178.

[0141] The targeting peptide may be inserted between AA588-589 of the AAV9 capsid protein or its functional equivalent in other AAV capsid proteins. The two adjacent amino acids may be AA588-589. In some embodiments, the targeting peptide is inserted between AA587-590 of the AAV9 capsid protein or its functional equivalent in other AAV capsid proteins.

[0142] The targeting peptide may include: (1) an amino acid sequence selected from SEQ ID NOs: 11-12 and SEQ ID NOs: 70-174; (2) an amino acid sequence having at least 80% sequence identity (e.g., 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100%, or a number or range between any two of these values) to an amino acid sequence selected from SEQ ID NOs: 11-12 and SEQ ID NOs: 70-174.

[0143] The targeting peptide can include (1) an amino acid sequence selected from SEQ ID NOs: 6-15 and 57, or (2) an amino acid sequence having at least 80% sequence identity (e.g., 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100%, or a number or range between any two of these values) to an amino acid sequence selected from SEQ ID NOs: 6-15 and 57.

[0144] The binding specificity between the targeting peptide carried by the rAAV and carbonic anhydrase IV can be screened using the multiplexed Cre recombination-based AAV targeted evolution (CREATE) method (M-CREATE). In M-CREATE, the rAAV nucleic acid contains a target sequence flanked by two lox sequences. An rAAV carrying a gene encoding a Cre recombinase that is expressed only in target cells (e.g., endothelial cells in the brain) is administered to an animal (e.g., a mouse). The target sequence of the rAAV that can enter the target cell is inverted by the Cre recombinase expressed in the target cell. The nucleic acid of the rAAV that lacks specificity for the target cell is inaccessible to the Cre recombinase, so its target sequence is not inverted. Thus, after sequencing the nucleic acid of the rAAV recovered from the animal, the targeting peptide of the rAAV that contains the inverted target sequence has specificity for the target cell. The M-CREATE method is described in detail in U.S. Patent Application Publication No. 20170166926 A1, the contents of which are incorporated by reference in their entirety for all purposes.

[0145] The creation of viral vectors can be achieved using any suitable genetic engineering technique known in the art, including but not limited to standard techniques of restriction endonuclease digestion, ligation, transformation, plasmid purification and DNA sequencing, for example, as described in Sambrook et al. (Molecular Cloning: A Laboratory Manual. Cold Spring Harbor Laboratory Press, NY (1989)). Viral vectors can incorporate sequences from the genome of any known organism. The sequences can be incorporated in their native form or can be modified in any way to obtain the desired activity. For example, the sequences can include insertions, deletions or substitutions. Use of AAV vectors and rAAV for payload delivery

[0146] Disclosed herein also includes compositions for use in delivering a payload (e.g., a pharmaceutical agent) to a target environment, such as the nervous system of a subject. The composition can include (1) an AAV capsid protein disclosed herein and (2) an AAV that includes an agent to be delivered to the target environment (e.g., the nervous system) of a subject.

[0147] The target environment may be the CNS, the peripheral nervous system (PNS), or a combination thereof. The target environment may be brain endothelial cells, neurons, capillaries in the brain, arterioles in the brain, arteries in the brain, or a combination thereof.

[0148] The agent to be delivered can include nucleic acid, peptide, small molecule, aptamer, or combination thereof. The AAV vector disclosed herein can effectively transduce the target environment (e.g., CNS) to deliver, for example, nucleic acid. In some embodiments, a method is provided for delivering nucleic acid sequence to the nervous system. The protein can be part of the capsid of AAV. The AAV can include the nucleic acid sequence to be delivered to the nervous system. The AAV can then be administered to a subject.

[0149] In some embodiments, the nucleic acid sequence delivered to the target environment (e.g., the nervous system) comprises one or more sequences that have some use or benefit to the nervous system and / or tissue or environment at or near the site of delivery. In some embodiments, it may be a nucleic acid encoding a protein of interest. The nucleic acid may comprise one or more of: a) a DNA sequence encoding a trophic factor, growth factor, or soluble protein; b) a cDNA that restores protein function to a human or animal with one or more genetic mutations in that gene; c) a cDNA that encodes a protein that can be used to control or modify the activity or state of a cell; d) a cDNA that encodes a protein or nucleic acid that can be used to evaluate the state of a cell; e) a cDNA that encodes a protein or guide RNA for gene editing; f) a DNA sequence for genome editing by homologous recombination; g) a DNA sequence that encodes a therapeutic RNA; h) an shRNA or artificial miRNA delivery system; and i) a DNA sequence that affects the splicing of an endogenous gene.

[0150] In some embodiments, the vector can also include regulatory control elements known to those of skill in the art for affecting expression of the RNA and / or protein products encoded by the polynucleotide in the desired cells of a subject.

[0151] Functionally, the expression of a polynucleotide may be at least partially controlled by an operably linked regulatory element, which regulates the transcription of the polynucleotide, the transport, processing and stability of the RNA encoded by the polynucleotide, and, if necessary, the translation of the transcript. A specific example of an expression control element is a promoter, which is usually located 5' of the transcription sequence. Another example of an expression control element is an enhancer, which may be located 5' or 3' of the transcription sequence or within the transcription sequence. Another example of a regulatory element is a recognition sequence for microRNA. Another example of a regulatory element is an intron and splice donor and splice acceptor sequences that regulate the splicing of the intron. Another example of a regulatory element is a transcription termination signal and / or a polyadenylation sequence.

[0152] Expression control elements and promoters include those active in a specific tissue or cell type, referred to herein as "tissue-specific expression control elements / promoters". Tissue-specific expression control elements are typically active in a specific cell or tissue (e.g., liver, brain, central nervous system, spinal cord, eye, retina or lung). Expression control elements are typically active in a specific cell, tissue or organ type because they are recognized by transcriptional activator proteins or other regulators of transcription that are specific to these cells, tissues or organ types.

[0153] Expression control elements also include ubiquitous or promiscuous promoters / enhancers that can drive the expression of polynucleotides in many different cell types.Such elements include, but are not limited to, cytomegalovirus (CMV) immediate early promoter / enhancer sequences, Rous sarcoma virus (RSV) promoter / enhancer sequences, CMV, chicken β-actin, rabbit β-globin (CAG) promoter / enhancer sequences, and other viral promoters / enhancers that are active in various mammalian cell types; promoters / enhancer sequences from mammalian genes that are ubiquitously or promiscuous expressed, including but not limited to beta-actin, ubiquitin, or EF1 alpha; or synthetic elements that do not occur in nature.

[0154] Expression control elements can also confer expression in a regulatable manner, i.e., a signal or stimulus increases or decreases the expression of an operably linked polynucleotide. Regulatable elements that increase the expression of an operably linked polynucleotide in response to a signal or stimulus are also referred to as "inducible elements" (i.e., induced by a signal). Particular examples include, but are not limited to, hormone (e.g., steroid) inducible promoters. Regulatable elements that decrease the expression of an operably linked polynucleotide in response to a signal or stimulus are referred to as "repressible elements" (i.e., the signal decreases expression, such that when the signal is removed or absent, expression increases). Typically, the amount of increase or decrease imparted by such elements is proportional to the amount of signal or stimulus present, the greater the amount of signal or stimulus, the greater the increase or decrease in expression.

[0155] The heterologous nucleic acid may include a 5'ITR and a 3'ITR. The agent may include a DNA sequence encoding a protein (e.g., a trophic factor, a growth factor, or a soluble protein). The heterologous nucleic acid may include a promoter operably linked to a polynucleotide encoding, for example, a protein or an RNA agent. The promoter may induce transcription of the polynucleotide. Transcription of the polynucleotide may generate a transcript. The heterologous nucleic acid may include one or more of a 5'UTR, a 3'UTR, a mini-promoter, an enhancer, a splicing signal, a polyadenylation signal, a terminator, one or more silencer effector binding sequences, a proteolytic signal, and an internal ribosome entry element (IRES). The silencer effector may include a microRNA (miRNA), a precursor microRNA (pre-miRNA), a small interfering RNA (siRNA), a short hairpin RNA (shRNA), precursors thereof, derivatives thereof, or combinations thereof. Silencer effector can bind to one or more silencer effector binding sequences, thereby reducing the stability of transcripts and / or reducing the translation of transcripts.In some embodiments, silencing effector comprises one or more miRNA binding sites (e.g., miR-122 binding sites).miRNA binding sites are typically operably linked regulatory elements located in the 3'UTR of transcriptional sequences.The binding of miRNA to target transcripts (RNA-induced silencing complex, complex with RISC) can reduce the expression of target transcripts through translation inhibition and / or transcript degradation.

[0156] The polynucleotide can further comprise a transcript stabilizing element. The transcript stabilizing element can comprise woodchuck hepatitis post-translational regulatory element (WPRE), bovine growth hormone polyadenylation (bGH-polyA) signal sequence, human growth hormone polyadenylation (hGH-polyA) signal sequence, or any combination thereof. The nucleic acid can be an RNA agent or can code an RNA agent. The RNA agent can comprise dsRNA, siRNA, shRNA, pre-miRNA, pri-miRNA, miRNA, stRNA, lncRNA, piRNA and snoRNA. The RNA agent inhibits or suppresses one or more of the expression of a gene of interest in a cell. In some embodiments, the gene of interest may be selected from SOD1, MAPT, APOE, HTT, C90RF72, TDP-43, APP, BACE, SNCA, ATXN1, ATXN2, ATXN3, ATXN7, SCN1A-SCN5A, and SCN8A-SCN11A. The heterologous nucleic acid may further comprise a polynucleotide encoding one or more secondary proteins, and the protein and the one or more secondary proteins may comprise one or more of a synthetic protein circuit. The heterologous nucleic acid may comprise a single stranded AAV (ssAAV) vector or a self-complementary AAV (scAAV) vector.

[0157] The promoter can include a ubiquitous promoter, such as a cytomegalovirus (CMV) immediate early promoter, a CMV promoter, a viral simian virus 40 (SV40) (e.g., early or late), a Moloney murine leukemia virus (MoMLV) LTR promoter, a Rous sarcoma virus (RSV) LTR, a RSV promoter, a herpes simplex virus (HSV) (thymidine kinase) promoter, a H5, P7.5 and P11 promoter from vaccinia virus, an elongation factor 1-alpha (EF1a) promoter, an early growth response 1 (EGR1), a ferritin H (FerH), a ferritin L (FerL), a glyceraldehyde 3-phosphate dehydrogenase (GAPDH), a true leukemia virus (LV) promoter, a cytomegalovirus (CV ... The promoter may be selected from eukaryotic translation initiation factor 4A1 (EIF4A1), heat shock 70 kDa protein 5 (HSPA5), heat shock protein 90 kDa beta, member 1 (HSP90B1), heat shock protein 70 kDa (HSP70), beta-kinesin (beta-KIN), human ROSA26 locus, ubiquitin C promoter (UBC), phosphoglycerate kinase-1 (PGK) promoter, 3-phosphoglycerate kinase promoter, cytomegalovirus enhancer, human beta-actin (HBA) promoter, chicken beta-actin (CBA) promoter, CAG promoter, CBH promoter, or any combination thereof.

[0158] The promoter may be an inducible promoter, including, but not limited to, a tetracycline-responsive promoter, a TRE promoter, a Tre3G promoter, an ecdysone-responsive promoter, a cumate-responsive promoter, a glucocorticoid-responsive promoter, and an estrogen-responsive promoter, a PPAR-γ promoter, an RU-486-responsive promoter, or a combination thereof.

[0159] The promoter may include tissue-specific promoters and / or lineage-specific promoters. The tissue-specific promoter may be a liver-specific thyroxine-binding globulin (TBG) promoter, an insulin promoter, a glucagon promoter, a somatostatin promoter, a pancreatic polypeptide (PPY) promoter, a synapsin-1 (Syn) promoter, a creatine kinase (MCK) promoter, a mammalian desmin (DES) promoter, an alpha-myosin heavy chain (a-MHC) promoter, or a cardiac troponin T (cTnT) promoter. The tissue-specific promoter may be a neuron-specific promoter, such as a synapsin-1 (Syn) promoter, a CaMKIIa promoter, a calcium / calmodulin-dependent protein kinase IIa promoter, a tubulin alpha I promoter, a neuron-specific enolase promoter, a platelet-derived growth factor beta chain promoter, a TRPV1 promoter, a Nav1.7 promoter, a Nav1.8 promoter, a Nav1.9 promoter, or an Advillin promoter. The tissue-specific promoter may be or include a muscle-specific promoter, such as a MCK promoter.

[0160] The promoter can include an intron sequence. The promoter can include a bidirectional promoter and / or an enhancer. In some embodiments, the enhancer is a CMV enhancer. The subject's one or more cells can include an endogenous version of a nucleic acid sequence (e.g., a gene), and the promoter can include or be derived from the endogenous version of the promoter. In some embodiments, the subject's one or more cells can include an endogenous version of a nucleic acid sequence, and the sequence is not truncated relative to the endogenous version.

[0161] Promoters can vary in length, for example, they may be less than 1 kb. In other embodiments, the promoter is greater than 1 kb. Promoters can be 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630, 640, 650, 660, 670, 680, 690, 700, 710, 720, 730, 740, 750, 760, 770, 780, 790, 800, 810, 820, 830, 840, 850, 860, 870, 880, 890, 900, 910, 920, 930, 940, 950, 960, 970, 980, 990, 1000, 1010, 1020, 1030, 1040, 1050, 1060, 1070, 1080, 1090, 1090, 1010 The promoter may have a length of 70, 580, 590, 600, 610, 620, 630, 640, 650, 660, 670, 680, 690, 700, 710, 720, 730, 740, 750, 760, 770, 780, 790, 800 bp, or a number or range between any two of these values, or a length of 800 bp or more. The promoter may provide expression of the therapeutic gene expression product for a period of time in a target tissue, such as, but not limited to, the CNS.Expression of therapeutic gene products was measured at 1 hr, 2 hr, 3 hr, 4 hr, 5 hr, 6 hr, 7 hr, 8 hr, 9 hr, 10 hr, 11 hr, 12 hr, 13 hr, 14 hr, 15 hr, 16 hr, 1 hr, 18 hr, 19 hr, 20 hr, 21 hr, 22 hr, 23 hr, 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 1 week, 8 days, 9 days ,10th,11th,12th,13th,2 weeks,15th,16th,17th,18th,19th,20th,3 weeks,22nd,23rd,24th,25th,26th,27th,28th,29th,30th,31st,1 month,2 months,3 months,4 months,5 months,6 months,7 months,8 months,9 months,10 months,11 months,1 year,13 months,14 months,1 5 months, 16 months, 17 months, 18 months, 19 months, 20 months, 21 months, 22 months, 23 months, 2 years, 3 years, 4 years, 5 years, 6 years, 7 years, 8 years, 9 years, 10 years, 11 years, 12 years, 13 years, 14 years, 15 years, 16 years, 17 years, 18 years, 19 years, 20 years, 21 years, 22 years, 23 years, 24 years, 25 years, 26 years, 27 years, 28 years, 29 years, 3 years It may be 0 years, 31 years, 32 years, 33 years, 34 years, 35 years, 36 years, 37 years, 38 years, 39 years, 40 years, 41 years, 42 years, 43 years, 44 years, 45 years, 46 years, 47 years, 48 ​​years, 49 years, 50 years, 55 years, 60 years, 65 years, or a number or range between any two of these values, or for a period of 65 years or more.

[0162] As used herein, a "protein of interest" can be any protein, including naturally occurring and non-naturally occurring proteins. In some embodiments, a polynucleotide encoding one or more proteins of interest can be present in one of the AAV vectors disclosed herein, and the polynucleotide is operably linked to a promoter. In some examples, the promoter can drive the expression of the protein of interest in a host cell (e.g., an endothelial cell). In some embodiments, the protein of interest is an anti-tau antibody, an anti-AB antibody, and / or an ApoE isoform.

[0163] The proteins can include aromatic L-amino acid decarboxylase (AADC), survival motor neuron 1 (SMN1), frataxin (FXN), cystic fibrosis transmembrane conductance regulator (CFTR), factor X (FIX), RPE65, retinoid isomerohydrolase (RPE65), sarcoglycan alpha (SGCA), and sarco / endoplasmic reticulum Ca2+-ATPase (SERCA2a), ApoE2, GBA1, GRN, ASP A, CLN2, GLB1, SGSH, NAGLU, IDS, NPC1, GAN, CFTR, GDE, OTOF, DYSF, MYO7A, ABCA4, F8, CEP290, CDH23, DMD, ALMS1, or any combination thereof.

[0164] The protein can include disease-related proteins. In some embodiments, the expression level of the disease-related proteins correlates with the onset and / or progression of the disease. The protein can include methyl-CpG binding protein 2 (MeCP2), DRK1A, KAT6A, NIPBL, HDAC4, UBE3A, EHMT1, one or more genes encoded on chromosome 9q34.3, NPHP1, LIMK1, one or more genes encoded on chromosome 7q11.23, P53, TPI1, FGFR1 and related genes, RA1, SHANK3, CLN3, NF-1, TP53, PFK, CD40L, CYP19A1, PGRN, CHRNA7, PMP22, CD40LG, derivatives thereof, or any combination thereof.

[0165] In some embodiments, the nucleic acid may comprise a cDNA encoding a protein for controlling or monitoring a cellular activity or state and / or for evaluating a cellular state. The protein may comprise a fluorescent activity, a polymerase activity, a protease activity, a phosphatase activity, a kinase activity, a sumoylating activity, a desumoylating activity, a ribosylation activity, a derivatizing activity, a myristoylating activity, a demyristoylating activity, or any combination thereof. The protein may comprise a nuclease activity, a methyltransferase activity, a demethylase activity, a DNA repair activity, a DNA damage activity, a deamination activity, a dismutase activity, an alkylating activity, a depurinating activity, an oxidizing activity, a pyrimidine dimer forming activity, an integrase activity, a transposase activity, a recombinase activity, a polymerase activity, a ligase activity, a helicase activity, a photolyase activity, a glycosylase activity, an acetyltransferase activity, a deacetylase activity, an adenylating activity, a deadenylating activity, or any combination thereof. The protein may contain a nuclear localization signal (NLS) or a nuclear export signal (NES).

[0166] The protein may include a CRE recombinase, a GCaMP, a cell therapy component, a knockdown gene therapy component, a cell surface exposed epitope, or any combination thereof. The protein may include a chimeric antigen receptor. The protein may include a diagnostic agent (e.g., green fluorescent protein (GFP), enhanced green fluorescent protein (EGFP), yellow fluorescent protein (YFP), enhanced yellow fluorescent protein (EYFP), blue fluorescent protein (BFP), red fluorescent protein (RFP), TagRFP, Dronpa, Padron, mApple, mCherry, mruby3, rsCherry, rsCherryRev, derivatives thereof, or any combination thereof).

[0167] In some embodiments, the nucleic acid can include a cDNA encoding a protein for gene editing, or a guide RNA, or a DNA sequence for genome editing by homologous recombination. The protein can include a programmable nuclease. In some embodiments, the programmable nuclease is selected from SpCas9 or a derivative thereof; VRER, VQR, EQR SpCas9; xCas9-3.7; eSpCas9; Cas9-HF1; HypaCas9; evoCas9; HiFi Cas9; ScCas9; StCas9; NmCas9; SaCas9; CjCas9; CasX; Cas9 H940A nickase; Cas12 and its derivatives; dcas9-APOBEC1 fusions, BE3, and dcas9-deaminase fusions; dcas9-Krab, dCas9-VP64, dCas9-Tet1, and dcas9-transcriptional regulator fusions; Dcas9 fluorescent protein fusions; Cas13 fluorescent protein fusions; RCas9 fluorescent protein fusions; Cas13-adenosine deaminase fusions. Programmable nucleases can include zinc finger nucleases (ZFNs) and / or transcription activator-like effector nucleases (TALENs).Programmable nucleases include Streptococcus pyogenes Cas9 (SpCas9), Staphylococcus aureus Cas9 (SaCas9), zinc finger nucleases, TAL effector nucleases, meganucleases, MegaTALs, Tev-m TALENs, MegaTev, homing endonucleases, Cas1, Cas1B, Cas2, Cas3, Cas4, Cas5, Cas6, Cas7, Cas8, Cas9, Cas100, Csy1, Csy2, Csy3, Cse1, Cse2, Csc1, Csc2, Csa5, Csn2, Csm2, Csm3, Csm4, Csm5, Csm6, Cmr1, Cmr3, Cmr4, Cmr5, Cmr6, C The heterologous nucleic acid and / or rAAV may comprise a polynucleotide encoding (i) a targeting molecule and / or (ii) a donor nucleic acid. The targeting molecule may be associated with a programmable nuclease. The targeting molecule may comprise a single-stranded DNA or a single-stranded RNA. The targeting molecule may comprise a single guide RNA (sgRNA).

[0168] The rAAV disclosed herein can include one or more heterologous nucleic acids disclosed herein. The heterologous nucleic acid can include a polynucleotide encoding a protein. The nucleic acid can be or encode an RNA agent. The heterologous nucleic acid can include a promoter operably linked to a polynucleotide encoding a protein. As disclosed herein, in some embodiments, the gene is operably linked to a suitable regulatory element. The one or more genes of the heterologous nucleic acid can include siRNA, shRNA, antisense RNA oligonucleotide, antisense miRNA, trans-splicing RNA, guide RNA, single guide RNA, crRNA, tracrRNA, trans-splicing RNA, pre-mRNA, mRNA, or any combination thereof. The one or more genes of the heterologous nucleic acid can include one or more synthetic protein circuit components. The one or more genes of the heterologous nucleic acid can include an entire synthetic protein circuit including one or more synthetic protein circuit components. The one or more genes of the heterologous nucleic acid can include two or more synthetic protein circuits.

[0169] Protein can be any protein, including naturally occurring and non-naturally occurring proteins.Examples include, but are not limited to, luciferase; fluorescent protein (e.g., GFP); growth hormone (GH) and its variants; insulin-like growth factor (IGF) and its variants; granulocyte colony-stimulating factor (G-CSF) and its variants; erythropoietin (EPO) and its variants; insulin, such as proinsulin, preproinsulin, insulin, insulin analogs, etc.; antibody and its variants, such as hybrid antibody, chimeric antibody, humanized antibody, monoclonal antibody; antigen-binding fragment of antibody (Fab fragment), single chain variable fragment of antibody (scFV fragment); dystrophin and its variants; coagulation factor and its variants; cystic fibrosis transmembrane conductance regulator (CFTR) and its variants; and interferon and its variants.

[0170] Examples of proteins of interest include, but are not limited to, luciferase; fluorescent proteins (e.g., GFP); growth hormone (GH) and variants thereof; insulin-like growth factor (IGF) and variants thereof; granulocyte-colony stimulating factor (G-CSF) and variants thereof; erythropoietin (EPO) and variants thereof; insulin, such as proinsulin, preproinsulin, insulin, insulin analogs, etc.; antibodies and variants thereof, such as hybrid antibodies, chimeric antibodies, humanized antibodies, monoclonal antibodies; antigen-binding fragments of antibodies (Fab fragments), single-chain variable fragments of antibodies (scFV fragments); dystrophin and variants thereof; coagulation factors and variants thereof; CFTR and variants thereof; and interferons and variants thereof.

[0171] In some embodiments, the protein of interest is a therapeutic protein or a variant thereof. Non-limiting examples of therapeutic proteins include blood factors, such as β-globin, hemoglobin, tissue plasminogen activator, and clotting factors; colony stimulating factors (CSF); interleukins, such as IL-1, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, and the like; growth factors, such as keratinocyte growth factors (GF), stem cell factors (SCF), fibroblast growth factors (FGF, such as basic FGF and acidic FGF), hepatocyte growth factors (HGF), insulin-like growth factors (IGF), bone morphogenetic proteins (BMP). , epidermal growth factor (EGF), growth differentiation factor-9 (GDF-9), hepatoma-derived growth factor (HDGF), myostatin (GDF-8), nerve growth factor (NGF), neurotrophins, platelet-derived growth factor (PDGF), thrombopoietin (TPO), transforming growth factor alpha (TGF-a), transforming growth factor beta (TGF-β), etc.; soluble receptors, such as soluble TNF-a receptor, soluble VEGF receptor, soluble interleukin receptors (e.g., soluble IL-1 receptor and soluble type II IL-1 receptor), soluble gamma / delta T cell receptors, ligand-binding fragments of soluble receptors, etc.; enzymes, such as -glucosidase, imiglucase, β-glucocerebrosidase, alglucerase, etc.; enzyme activators, such as tissue plasminogen activator; chemokines, such as monokines induced by IP-10, interferon-gamma (Mig), Groa / IL-S, RANTES, MIP-la, μΙΡ-Ιβ, MCP-1, PF-4, etc.; angiogenic agents, such as vascular endothelial growth factor (VEGF, e.g. VEGF121, VEGF165, VEGF-C, VEGF-2), transforming growth factor beta, basic fibroblast growth factor, glioma-derived growth factor, angiogenin, angiogenin-2, etc.; antiangiogenic agents, such as soluble VEGF receptors; protein vaccines;Neuroactive peptides, such as nerve growth factor (NGF), bradykinin, cholecystokinin, gastin, secretin, oxytocin, gonadotropin releasing hormone, beta-endorphin, enkephalin, substance P, somatostatin, prolactin, galanin, growth hormone releasing hormone, bombesin, dynorphin, warfarin, neurotensin, motilin, thyrotropin, neuropeptide Y, luteinizing hormone, calcitonin, insulin, glucagon, vasopressin, angiotensin II, thyrotropin releasing hormone, vasoactive intestinal peptide, sleep peptides, etc.; thrombolytic agents ;atrial natriuretic peptide;relaxin;glial fibrillary acidic protein;follicle-stimulating hormone (FSH);human alpha-1 antitrypsin;leukemia inhibitory factor (LIF);transforming growth factor (TGF);tissue factor, luteinizing hormone;macrophage-activating factor;tumor necrosis factor (TNF);neutrophil chemotactic factor (NCF);nerve growth factor;tissue inhibitor of metalloproteinases;vasoactive intestinal peptide;angiogenin;angiotropin;fibrin;hirudin;IL-1 receptor antagonist, etc. Some other non-limiting examples of proteins of interest include ciliary neurotrophic factor (CNTF); brain-derived neurotrophic factor (BDNF); neurotrophin 3 and 4 / 5 (NT-3 and 4 / 5); glial cell line-derived neurotrophic factor (GDNF); aromatic amino acid decarboxylase (AADC); hemophilia-related coagulation proteins such as factor IX or factor X; dystrophin or nini-dystrophin; lysosomal acid lipase; phenylalanine hydroxylase (PAH); glycogen storage disease-related enzymes such as glucose-6-phosphatase, acid maltase, glycogen debranching enzyme, muscle glycogen phosphorylase, liver glycogen phosphorylase, muscle phosphofructokinase, phosphorylase kinase (e.g., PHKA2), glucose transporters (e.g., GLUT2), aldolase A, beta-enolase, glycogen synthase; lysosomal enzymes (e.g., beta-N-acetylhexosaminidase A); and any variants thereof.

[0172] The protein of interest can be, for example, an active fragment of a protein such as any of the aforementioned proteins, a fusion protein comprising part or all of two or more proteins, or a fusion protein comprising all or a portion of any of the aforementioned proteins.

[0173] In some embodiments, the viral vector comprises a polynucleotide that comprises the coding region of two or more proteins of interest, and the two or more proteins of interest can be the same or different from each other. In some embodiments, the two or more proteins of interest are related polypeptides, such as the light and heavy chains of the same antibody.

[0174] The protein of interest may be a multi-subunit protein. For example, the protein of interest may comprise two or more subunits, or two or more independent polypeptide chains. In some embodiments, the protein of interest may be an antibody, including, but not limited to, antibodies of various isotypes (e.g., IgG1, IgG2, IgG3, IgG, IgA, IgD, IgE, and IgM); a monoclonal antibody produced by any means known to those skilled in the art, including antigen-binding fragments of monoclonal antibodies; a humanized antibody; a chimeric antibody; a single-chain antibody; an antibody fragment, such as Fv, F(ab')2, Fab', Fab, Facb, scFv, etc., provided that the antibody is capable of binding to the antigen. In some embodiments, the antibody is a full-length antibody. In some embodiments, the protein of interest is not an immunoadhesin.

[0175] In some embodiments, the resulting targeting molecules can be used in methods and / or treatments related to in vivo gene transfer applications to long-lived cell populations. In some embodiments, they can be applied to any rAAV-based gene therapy, including, for example, spinal muscular atrophy (SMA), amyotrophic lateral sclerosis (ALS), Parkinson's disease, Friedreich's ataxia, Pompe's disease, Huntington's disease, Alzheimer's disease, Batten's disease, lysosomal storage disorders, glioblastoma multiforme, Rett's syndrome, Leber's congenital muscular atrophy, chronic pain, stroke, spinal cord injury, traumatic brain injury, and lysosomal storage disorders. Additionally, rAAVs can also be used for in vivo delivery of transgenes for non-therapeutic scientific studies such as optogenetics, gene overexpression, gene knockdown with shRNA or miRNA, modulation of endogenous miRNA using miRNA sponges or decoys, recombinase delivery for conditional gene deletion, conditional (recombinase-dependent) expression, or gene editing with CRISPR, TALEN, and zinc finger nucleases.

[0176] In some embodiments, the gene encodes an immunogenic material, such as an antigenic peptide or protein derived from a pathogen, that can stimulate an immune response (e.g., an adaptive immune response). Expression of the antigen can stimulate the body's adaptive immune system to provide an adaptive immune response. Thus, it is believed that some embodiments of the heterologous nucleic acid provided herein can be used as a vaccine (e.g., as a vaccine) for the prevention or treatment of infectious diseases.

[0177] As described herein, the nucleotide sequence encoding a protein can be modified to improve the expression efficiency of the protein.The method that can be used to improve the transcription and / or translation of the gene herein is not particularly limited.For example, the nucleotide sequence can be modified to better reflect the codon usage frequency of the host in order to increase gene expression (e.g., protein production) in the host (e.g., mammal).

[0178] The degree of gene expression in target cells can vary.The amount of protein expressed in a subject (e.g., the CNS of a subject) can vary.For example, in some embodiments, protein can be expressed in a subject in an amount of at least about 9 μg / ml, at least about 10 μg / ml, at least about 50 μg / ml, at least about 100 μg / ml, at least about 200 μg / ml, at least about 300 μg / ml, at least about 400 μg / ml, at least about 500 μg / ml, at least about 600 μg / ml, at least about 700 μg / ml, at least about 800 μg / ml, at least about 900 μg / ml, or at least about 1000 μg / ml. In some embodiments, the protein is expressed in the subject in an amount of about 9 μg / ml, about 10 μg / ml, about 50 μg / ml, about 100 μg / ml, about 200 μg / ml, about 300 μg / ml, about 400 μg / ml, about 500 μg / ml, about 600 μg / ml, about 700 μg / ml, about 800 μg / ml, about 900 μg / ml, about 1000 μg / ml, about 1500 μg / ml, about 2000 μg / ml, about 2500 μg / ml, or a range between any two of these values. Those skilled in the art will understand that the expression level required for the protein for the method to be effective may vary depending on non-limiting factors such as the particular protein and the subject being treated, and that the effective amount of protein can be readily determined using conventional methods known to those of skill in the art without undue experimentation.

[0179] The agent may be an inducer of cell death. The agent may induce cell death by a non-intrinsic cell death pathway (e.g., bacterial pore-forming toxins). In some embodiments, the agent (e.g., a protein encoded by the nucleic acid) may be a pro-survival protein. In some embodiments, the agent is a modulator of the immune system. The agent may activate an adaptive immune response, an innate immune response, or both. In some embodiments, the nucleic acid encodes an immunogenic material, e.g., an antigenic peptide or protein from a pathogen, that can stimulate an immune response (e.g., an adaptive immune response). Expression of the antigen may stimulate the body's adaptive immune system to provide an adaptive immune response. Thus, it is contemplated that some embodiments of the compositions provided herein can be used as a vaccine for the prevention or treatment of infectious diseases (e.g., as a vaccine). The protein may include a CRE recombinase, a GCaMP, a cell therapy component, a knockdown gene therapy component, a cell surface exposed epitope, or any combination thereof. In some embodiments, the proteins include CFTR, GDE, OTOF, DYSF, MYO7A, ABCA4, F8, CEP290, CDH23, DMD, and ALMS1.

[0180] The agents can include non-protein-coding genes such as RNA agents, e.g., antisense RNA, RNAi, shRNA and microRNA (miRNA), miRNA sponges or decoys, recombinase delivery for conditional gene deletion, sequences encoding conditional (recombinase-dependent) expression (including those required for gene editing components described herein). Non-protein-coding genes can also encode tRNA, rRNA, tmRNA, piRNA, double-stranded RNA, snRNA, snoRNA, and / or long non-coding RNA (IncRNA). In some embodiments, the RNA agent can include non-natural or modified nucleotides (e.g., pseudouridine). In some embodiments, the non-protein-coding genes can regulate the expression or activity of a target gene or gene expression product. For example, the RNAs described herein can be used to inhibit gene expression in a target cell, e.g., a cell in the central nervous system (CNS). In some embodiments, inhibition of gene expression refers to at least about 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 95% or 100% inhibition. In some cases, the protein product of the target gene is inhibited by at least about 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 95% or 99%. The gene can be either a wild type gene or a gene with at least one mutation. The target protein can be a wild type protein or a protein with at least one mutation.

[0181] Examples of genes encoding therapeutic proteins include sequences associated with signal transduction biochemical pathways, such as signal transduction biochemical pathway-associated genes or polynucleotides (e.g., signal transducers). In some embodiments, the methods and compositions disclosed herein include knockdown of endogenous signal transducers with regulated expression of proteins that contain the appropriate version of the signal transducers. Examples of DNA or RNA sequences contemplated herein include disease-associated gene or polynucleotide sequences. A "disease-associated" gene or polynucleotide refers to any gene or polynucleotide that produces abnormal levels or abnormal forms of transcription or translation products in cells derived from disease-affected tissues compared to non-disease control tissues or cells. It may be a gene that becomes expressed at abnormally high levels. It may be a gene that becomes expressed at abnormally low levels, where the altered expression correlates with the development and / or progression of the disease. A disease-associated gene also refers to a gene that has a mutation or genetic variation that is directly involved or in linkage disequilibrium with a gene involved in the pathogenesis of the disease. The transcription or translation product may be known or unknown, and may be at normal or abnormal levels. The signal transducers may be associated with one or more diseases or disorders. In some embodiments, disease or disorder is characterized by abnormal signal transduction of one or more signal transduction substances disclosed herein.In some embodiments, the activation level of signal transduction substance correlates with the occurrence and / or progression of disease or disorder.The activation level of signal transduction substance may directly or indirectly be involved in the pathogenesis of disease or disorder.

[0182] Many proteins (e.g., enzymes) can be secreted and exert cross-correction effects. For these, the AAVs of the present disclosure can be used to deliver genetic material to brain endothelial cells and transform these cells into biofactories to produce therapeutics and distribute them to other cell types. For example, production of secreted Sparcl1 / Hevin protein in brain endothelial cells can rescue the thalamocortical synapse loss phenotype of Hevin KO mice (see Example 1 below). This proof of concept supports the brain endothelial cell biofactory model for the production of enzymes, antibodies or other biological therapeutics, providing a novel therapeutic approach for diseases such as lysosomal storage disorders.

[0183] In some embodiments, rAAVs having capsid proteins that include one or more targeting peptides disclosed herein can be used to deliver genes to specific cell types in a target environment of a subject. For example, rAAVs can be used to deliver genes to neurons and glia in the nervous system (including the PNS, CNS, or both) of a subject (e.g., a mammal). The compositions and methods disclosed herein can be used, for example, to (i) reduce expression of mutant huntingtin in patients with Huntington's disease, e.g., by incorporating a huntingtin-specific microRNA expression cassette within the rAAV genome and packaging the rAAV genome into a variant rAAV for delivery, e.g., via the vasculature, (ii) deliver a functional copy of the frataxin gene to patients with Friedreich's ataxia, (iii) restore expression of an enzyme important for normal lysosomal function in patients (e.g., patients with Niemann-Pick disease, mucopolysaccharidosis III, and / or Gaucher disease) that lack expression of the enzyme due to a genetic mutation, (iv) use rAAVs to generate animal models of disease, or combinations thereof.

[0184] The subject in need is a subject suffering from or at risk of developing one or more of chronic pain, Friedreich's ataxia, Huntington's disease (HD), Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), spinal muscular atrophy types I and II (SMA I and II), Friedreich's ataxia (FA), spinocerebellar ataxia, multiple sclerosis (MS), chronic traumatic encephalopathy (CTE), HIV-1 associated dementia, or a lysosomal storage disorder involving cells within the CNS. The lysosomal storage disorder can be Krabbe disease, Sandhoff disease, Tay-Sachs disease, Gaucher disease (types I, II, or III), Niemann-Pick disease (NPC1 or NPC2 deficiency), Hurler syndrome, Pompe disease, or Batten disease.

[0185] In some embodiments, the subject is suffering from an acute condition or injury. A subject in need may be suffering from, at risk of developing, or suffering from stroke, traumatic brain injury, epilepsy, or spinal cord injury. Pharmaceutical Compositions and Methods of Administration

[0186] Also disclosed herein is a pharmaceutical composition comprising one or more rAAV viruses disclosed herein and one or more pharma- ceutically acceptable carriers. The composition may also include additional components such as diluents, stabilizers, excipients, and adjuvants. As used herein, a "pharma-ceutically acceptable" carrier, excipient, diluent, adjuvant, or stabilizer is non-toxic (preferably inert) to cells or subjects exposed at the dosage and concentration used, or has an acceptable level of toxicity as determined by those skilled in the art. Carriers, diluents and adjuvants can include buffers such as phosphate, citrate or other organic acids; antioxidants such as ascorbic acid; low molecular weight polypeptides (e.g., less than about 10 residues); proteins such as serum albumin, gelatin or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as glycine, glutamine, asparagine, arginine, lysine; monosaccharides, disaccharides and other carbohydrates including glucose, mannose or dextrins; chelating agents such as EDTA; sugar alcohols such as mannitol or sorbitol; salt-forming counterions such as sodium; and / or non-ionic surfactants such as Tween™, Pluronics™ or polyethylene glycol (PEG). In some embodiments, the physiologically acceptable carrier is a pH buffered aqueous solution.

[0187] Disclosed herein is a method of delivering an agent to the nervous system of a subject. In some embodiments, the method comprises providing an AAV vector comprising the AAV capsid protein disclosed herein. In some embodiments, the AAV vector comprises the agent to be delivered to the nervous system. In some embodiments, the method comprises administering the AAV vector to a subject. The composition can be for intravenous administration. The composition can be for systemic administration. The agent can be delivered to the endothelial lining of the ventricles of the subject's brain, the central canal of the spinal cord, the capillaries of the brain, the arterioles of the brain, the arteries of the brain, or a combination thereof. The subject can be an adult animal.

[0188] The titer of the administered rAAV varies, for example, depending on the specific rAAV, the mode of administration, the treatment goal, the individual, and the cell type targeted, and can be determined by standard methods in the art. As is readily apparent to those skilled in the art, the useful in vivo dosage and the specific mode of administration of the administered recombinant virus will vary depending on the age, weight, severity of the affliction, and the animal species being treated, the specific recombinant virus expressing the protein of interest used, and the specific use for which the recombinant virus is used. The determination of effective dosage levels, i.e., the dosage levels required to achieve the desired result, can be achieved by those skilled in the art using routine pharmacological methods. Typically, human clinical application of the product will begin at a lower dosage level, and the dosage level will be increased until the desired effect is achieved. Alternatively, acceptable in vitro studies can be used to establish the useful dose and route of administration of the composition identified by the present method using established pharmacological methods.

[0189] The exact dosage can be determined on a drug-by-drug basis, and in most cases some generalizations regarding dosage can be made. In some embodiments, rAAV for delivery of an agent to the nervous system (e.g., CNS) of a subject is administered at a dose of 1×10 per kg of subject, e.g., by injection. 10 Viral genome (vg) ~2×10 l4 vg / kg, e.g., 5×10 11 vg / kg~5×l0 12 In some embodiments, the dose of rAAV administered to a subject is between 2×10 vg / kg. 14 In some embodiments, the dose of rAAV administered to a subject is 5×10 per kg. 12 In some embodiments, the dose of rAAV administered to a subject is 5×10 vg / kg. 11 vg.

[0190] Effective doses and administration amounts of pharmaceutical compositions for preventing or treating a disease or condition disclosed herein are defined by an observed beneficial response associated with the disease or condition, or a symptom of the disease or condition. A beneficial response includes preventing, alleviating, arresting, or curing the disease or condition, or a symptom of the disease or condition. In some embodiments, a beneficial response may be measured by detecting a measurable improvement in the presence, level, or activity of a biomarker, transcriptome risk profile, or gut microbiota in a subject. As used herein, "improvement" refers to a shift in the presence, level, or activity to that observed in a normal individual (e.g., an individual not afflicted with the disease or condition). If a therapeutic rAAV composition is not therapeutically effective or does not provide sufficient relief of the disease or condition, or a symptom of the disease or condition, the dosage and / or route of administration may be altered, or an additional agent may be administered to the subject along with the therapeutic rAAV composition. In some embodiments, once a patient has been initiated on a regimen of the therapeutic rAAV composition, the patient is also weaned off the second treatment regimen (e.g., dose de-escalation).

[0191] In some embodiments, pharmaceutical compositions according to the present disclosure are administered at a dosage level sufficient to deliver about 0.0001 mg / kg to about 100 mg / kg, about 0.001 mg / kg to about 0.05 mg / kg, about 0.005 mg / kg to about 0.05 mg / kg, about 0.001 mg / kg to about 0.005 mg / kg, about 0.05 mg / kg to about 0.5 mg / kg, about 0.01 mg / kg to about 50 mg / kg, about 0.1 mg / kg to about 40 mg / kg, about 0.5 mg / kg to about 30 mg / kg, about 0.01 mg / kg to about 10 mg / kg, about 0.1 mg / kg to about 10 mg / kg, or about 1 mg / kg to about 25 mg / kg of the subject's body weight, one or more times per day, to achieve the desired therapeutic, diagnostic, or prophylactic effect. It will be appreciated that the above dosage concentrations can be converted to vg or viral genomes / kg or total viral genomes administered by one of skill in the art.

[0192] In some embodiments, the dose of the pharmaceutical composition is at least or about 10 7 , 10 8 , 10 9 , 10 10 , 10 11 , 10 12 , 10 13 , 10 14 , 10 15 , 10 16 , or 10 17 In some cases, the concentration of infectious particles is 2×10 7 ,2×10 8 , 2×10 9 , 2×10 10 , 2×10 11 , 2×10 12 , 2×10 13 , 2×10 14 , 2×10 15 , 2×10 16 , 2×10 17 , or ranges between any two of these values. In some cases, the concentration of infectious particles is greater than 3 x 10 7 , 3×10 8 , 3×10 9 , 3×10 10 , 3×10 11 , 3×10 12 , 3×10 13 , 3×10 14 , 3×10 15 , 3×10 16 , 3×10 17 , or ranges between any two of these values. In some cases, the concentration of infectious particles is 4 x 10 7 , 4×10 8 , 4×10 9 , 4×10 10 , 4×10 1 , 4×10 12 , 4×10 13 , 4×10 14 , 4×10 15 , 4×10 16 , 4×10 17 , or a range between any two of these values. In some cases, the concentration of infectious particles is 5 x 10 7 , 5×10 8 , 5×109 , 5×10 10 , 5×10 11 , 5×10 12 , 5×10 13 , 5×10 14 , 5×10 15 , 5×10 16 , 5×10 17 , or ranges between any two of these values. In some cases, the concentration of infectious particles is 6 x 10 7 , 6×10 8 , 6×10 9 , 6×10 10 , 6×10 11 , 6×10 12 , 6×10 13 , 6×10 14 , 6×10 15 , 6×10 16 , 6×10 17 , or ranges between any two of these values. In some cases, the concentration of infectious particles is 7 x 10 7 , 7×10 8 , 7×10 9 , 7×10 10 , 7×10 11 , 7×10 12 , 7×10 13 , 7×10 14 , 7×10 15 , 7×10 6 , 7×10 17 , or ranges between any two of these values. In some cases, the concentration of infectious particles is 8 x 10 7 , 8×10 8 , 8×10 9 , 8×10 10 , 8×10 11 , 8×10 12 , 8×10 13 , 8×10 14 , 8×10 15 , 8×10 16 , 8×10 17 , or ranges between any two of these values. In some cases, the concentration of infectious particles is 9 x 10 7 , 9×10 8 , 9×10 9 , 9×10 10 , 9×1011 , 9×10 12 , 9×10 13 , 9×10 14 , 9×10 15 , 9×10 16 , 9×10 17 , or a range between any two of these values.

[0193] The recombinant virus disclosed herein can be administered to a subject (e.g., a human) in need thereof. The route of administration is not particularly limited. For example, a therapeutically effective amount of the recombinant virus can be administered to a subject via a route that is standard in the art. The administration can be systemic administration. The administration can be intravenous administration.

[0194] Non-limiting examples of routes include intramuscular, intravaginal, intravenous, intraperitoneal, subcutaneous, epicutaneous, intradermal, rectal, intraocular, pulmonary, intracranial, intraosseous, oral, buccal, systemic, or nasal. In some embodiments, the recombinant virus is administered to the subject by systemic transduction. In some embodiments, the recombinant virus is administered to the subject by intramuscular injection. In some embodiments, the rAAV is administered to the subject by a parenteral route (e.g., by intravenous, intramuscular, or subcutaneous injection), by superficial scarring, or by inoculation into a body cavity of the subject. The route of administration and serotype of the AAV component of the rAAV virus can be readily determined by one of skill in the art, taking into consideration the infection and / or disease state to be treated, and the target cells / tissues expressing the protein of interest. In some embodiments, it may be advantageous to administer the rAAV via intravenous administration. The variant AAV provided herein can advantageously provide intravenous administration of the vector with enhanced tropism to the CNS.

[0195] In some embodiments, the subject is a primate and the agent is delivered to endothelial cells and / or neurons of the nervous system. The nervous system can be the central nervous system (CNS). The agent can be delivered to endothelial cells of the subject's nervous system at least 1.5 times, 2 times, or 3 times more efficiently than the agent is delivered to neurons of the nervous system. In some embodiments, the agent is delivered to endothelial cells of the subject's nervous system 3 times more efficiently (e.g., 3 times, 4 times, 5 times, 6 times, 7 times, 8 times, 9 times, 10 times, 20 times, 30 times, 40 times, 50 times, 60 times, 70 times, 80 times, 90 times, 100 times, or a number or range between any of these values) than the agent is delivered to neurons of the nervous system.

[0196] Disclosed herein is a method for delivering an agent to a cell. In some embodiments, the method comprises contacting an AAV vector comprising the AAV capsid protein disclosed herein with a cell. In some embodiments, the AAV vector comprises an agent to be delivered to the nervous system. In some embodiments, the cell is an endothelial cell or a neuron. In some embodiments, the contacting of the AAV vector with the cell is performed in vitro, in vivo or ex vivo. The cell can be present in a tissue, an organ or a subject. The cell can be a brain endothelial cell, a neuron, a brain capillary cell, a brain arteriole cell, a brain arterial cell, a brain vasculature cell, or a combination thereof.

[0197] AAV vector can be AAV9 vector or its variant.In some embodiments, AAV vector is AAV1, AAV2, AAV3, AAV3b, AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, AAV10, human isolate hu.31, human isolate hu.32, rhesus isolate rh.8, rhesus isolate rh.10, or their variants.The serotype of AAV vector can be different from the serotype of AAV capsid.

[0198] The variant AAV capsid can be provided with tropism for tissues or cells of the central nervous system (CNS). The target cell can be a neuronal cell, a neural stem cell, an astrocyte, or a tumor cell. The target cell can be located in the brain or spinal cord. The target cell can include antigen-presenting cells, dendritic cells, macrophages, neuronal cells, brain cells, astrocytes, microglial cells, and neurons. In some embodiments, the target cell is an endothelial cell.

[0199] The actual administration of rAAV can be achieved by using any physical method that transports rAAV to the subject's nervous system. For example, the rAAV disclosed herein can be advantageously administered intravenously for delivery to the CNS. As disclosed herein, the capsid protein of rAAV can be modified so that rAAV targets a specific target environment of interest, such as the central nervous system, and enhances the tropism for the target environment of interest (e.g., CNS tropism). The pharmaceutical composition can be prepared, for example, as an injectable formulation.

[0200] The recombinant virus used can be utilized in liquid or lyophilized form (combined with one or more suitable preservatives and / or protectants to protect the virus during the lyophilization process). For gene therapy (e.g., of neurological disorders that can be ameliorated by a specific gene product), a therapeutically effective amount of the recombinant virus expressing a therapeutic protein is administered to a host in need of such treatment. The use of the recombinant virus disclosed herein in the manufacture of a pharmaceutical for inducing immunity in a host or for providing gene therapy to a host is within the scope of this application.

[0201] When human dosages of rAAV have been established for at least some indications, the same dosages or dosages that are about 0.1% to 500%, more preferably about 25% to 250%, of the established human dosages can be used. When human dosages have not been established, such as in the case of newly discovered pharmaceutical compositions, appropriate human dosages can be determined based on the ED as qualified by toxicity and efficacy studies in animals.50 Value or ID 50 values, or other appropriate values ​​obtained from in vitro or in vivo studies.

[0202] A therapeutically effective amount of rAAV can be administered to a subject at various times. For example, rAAV can be administered to a subject before, during, or after the subject develops a disease or disorder. rAAV can also be administered to a subject before, during, or after the onset of a disease or disorder (e.g., Huntington's disease (HD), Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, spinal muscular atrophy, types I and II, Friedreich's ataxia, spinocerebellar ataxia, and any lysosomal storage disorder involving cells within the CNS, including, but not limited to, Krabbe disease, Sandhoff disease, Tay-Sachs disease, Gaucher disease (types I, II, or 111), Niemann-Pick disease (NPC1 or NPC2 deficiency), Hurler syndrome, Pompe disease, Batten disease, or any combination thereof), chronic pain, or a combination thereof. In some embodiments, rAAV is administered to a subject during remission of a disease or disorder. In some embodiments, the rAAV is administered prior to the onset of a disease or disorder in a subject. In some embodiments, the rAAV is administered to a subject at risk of developing a disease or disorder.

[0203] The disease or disorder may include a neurological disease or disorder. For example, the neurological disease or disorder may be epilepsy, Dravet syndrome, Lennox-Gastaut syndrome, myoclonic seizures, juvenile myoclonic epilepsy, intractable epilepsy, schizophrenia, juvenile convulsions, West syndrome, infantile convulsions, intractable infantile convulsions, Alzheimer's disease, Creutzfeldt-Jakob syndrome / disease, bovine spongiform encephalopathy (BSE), prion-related infections, diseases involving mitochondrial dysfunction, diseases involving beta-amyloid and / or tauopathy, Down's syndrome, hepatic encephalopathy, Huntington's disease, motor neuron disease, amyotrophic lateral sclerosis (ALS), olivopontocerebellar atrophy, postoperative cognitive impairment (POCD), systemic lupus erythematosus, systemic sclerosis, and the like. dementia, Sjögren's syndrome, neuronal ceroid lipofuscinosis, neurodegenerative cerebellar ataxia, Parkinson's disease, Parkinsonian dementia, mild cognitive impairment, cognitive impairment in various forms of mild cognitive impairment, various forms of cognitive impairment, dementia pugilistica, vascular and frontal lobe dementia, cognitive impairment, learning disability, eye injury, eye disease, eye disorders, glaucoma, retinopathy, macular degeneration, head or brain or spinal cord injury, head or brain or spinal cord trauma, convulsions, epileptic convulsions, epilepsy, temporal lobe epilepsy, myoclonic epilepsy, tinnitus, dyskinesia, chorea, Huntington's chorea, athetosis, dystonia, stereotypies, ballism, tardive dyskinesia, tic disorder, spasmodic torticollisspasmodicus), blepharospasm, focal and generalized dystonia, nystagmus, hereditary cerebellar ataxia, corticobasal degeneration, tremor, essential tremor, addiction, anxiety disorder, panic disorder, social anxiety disorder (SAD), attention deficit hyperactivity disorder (ADHD), attention deficit syndrome (ADS), restless legs syndrome (RLS), hyperactivity in children, autism, dementia, dementia in Alzheimer's disease, dementia in Korsakoff's syndrome, Korsakoff's syndrome, vascular dementia, dementia associated with HIV infection, HIV-1 encephalopathy, AIDS encephalopathy, AIDS dementia complex, AIDS-related dementia, major depressive disorder, depression, memory loss, stress, bipolar depressive disorder, drug tolerance, drug tolerance to opioids, movement disorder, fragile X syndrome, irritable bowel syndrome (IBS), migraine, multiple sclerosis (MS), muscle spasms, pain, chronic pain, acute pain, inflammatory pain, neuropathic pain, post-traumatic stress disorder (PTSD), schizophrenia, spasticity, Tourette's syndrome, eating disorder, food addiction, agoraphobia, generalized anxiety disorder, obsessive-compulsive disorder, panic disorder, social phobia, phobic disorder, substance-induced anxiety disorder, delusional disorder, schizoaffective disorder, schizophreniform disorder, substance-induced psychotic disorder, high blood pressure, or any combination thereof.

[0204] In some embodiments, disclosed herein are formulations of pharma- ceutically acceptable excipients and carrier solutions suitable for delivery of the rAAV compositions described herein, as well as suitable administration and treatment regimens for using certain compositions described herein in various treatment regimens. In some embodiments, the amount of therapeutic gene expression product in each therapeutically useful composition may be prepared to obtain an appropriate dosage at any given unit dose of compound. Factors such as solubility, bioavailability, biological half-life, route of administration, product shelf life, and other pharmacological considerations are contemplated by those skilled in the art of preparing such pharmaceutical formulations, and thus various dosages and treatment regimens may be desirable. In some examples, the rAAV composition is a suitably formulated pharmaceutical composition disclosed herein that is delivered intraocularly, intravitreally, parenterally, subcutaneously, intravenously, intracerebroventricularly, intramuscularly, intrathecally, orally, intraperitoneally, by oral or nasal inhalation, or by direct injection into one or more cells, tissues, or organs. In some embodiments, the rAAV disclosed herein may be advantageously administered intravenously for delivery to the CNS.

[0205] In some embodiments, pharmaceutical forms of AAV-based virus compositions suitable for injectable use include sterile aqueous solutions or dispersions and sterile powders for the extemporaneous preparation of sterile injectable solutions or dispersions. Carriers can be solvents or dispersion media containing, for example, water, ethanol, polyol (for example, glycerol, propylene glycol, liquid polyethylene glycol, and the like), suitable mixtures thereof, and / or vegetable oils. Proper fluidity can be maintained, for example, by the use of a coating such as lecithin, by maintaining the required particle size in the case of dispersion, and by the use of surfactants. Prevention of microbial action can be achieved by various antibacterial and antifungal agents, for example, parabens, chlorobutanol, phenol, sorbic acid, thimerosal, and the like. In many cases, it is preferable to include isotonic agents, for example, sugars or sodium chloride. Prolonged absorption of injectable compositions can be achieved by the use of agents that delay absorption, for example, aluminum monostearate and gelatin in the composition.

[0206] In some embodiments, for administration of injectable aqueous solutions, for example, the solution may be appropriately buffered if necessary, and the liquid diluent is first made isotonic with sufficient saline or glucose. These particular aqueous solutions are particularly suitable for intravenous, intramuscular, subcutaneous and intraperitoneal administration. Some variation in dosage will necessarily occur depending on the condition of the subject being treated. The person responsible for administration will in any event determine the appropriate dose for each individual subject. In addition, for human administration, the preparation should meet the sterility, pyrogenicity, and general safety and purity standards required by FDA Office of Biologics standards.

[0207] Sterile injectable solutions containing the rAAV compositions disclosed herein are disclosed herein, which are prepared by incorporating the rAAV compositions disclosed herein in the required amount in a suitable solvent together with some of the other ingredients listed above as necessary, followed by sterilization by filtration.Generally, dispersions are prepared by incorporating various sterilized active ingredients into a sterile vehicle that contains a basic dispersion medium and other necessary ingredients from those listed above.In the case of sterile powders for the preparation of sterile injectable solutions, the preferred preparation method is vacuum drying and freeze-drying technology, which obtains a powder of active ingredient + any additional desired ingredients from its previously sterile filtered solution.Injectable solutions can be advantageous for systemic administration, for example, by intravenous administration.

[0208] Neutral or salt form formulations are also provided herein. Pharmaceutically acceptable salts include acid addition salts (formed with free amino groups of protein) formed with inorganic acids, such as hydrochloric acid or phosphoric acid, or organic acids such as acetic acid, oxalic acid, tartaric acid, mandelic acid, etc. Salts formed with free carboxyl groups can also be derived from inorganic bases, such as sodium hydroxide, potassium hydroxide, ammonium hydroxide, calcium hydroxide, or ferric hydroxide, and organic bases such as isopropylamine, trimethylamine, histidine, procaine, etc. When formulated, solutions are administered in a manner compatible with the dosage formulation and in a therapeutically effective amount. The formulations are easily administered in a variety of dosage forms, such as injectable solutions, drug release capsules, etc.

[0209] Formulations for intranasal administration may comprise a coarse powder containing the active ingredient and having an average particle size of about 0.2 μm to 500 μm. Such formulations are administered in the manner of snuffing, for example by rapid inhalation through the nasal passages from a container of powder held close to the nose. Formulations suitable for nasal administration may contain, for example, as little as 0.1% (w / w) to as much as 100% (w / w) of the active ingredient, and may include one or more additional ingredients described herein. Pharmaceutical compositions may be prepared, packaged, and / or sold in a formulation suitable for buccal administration. Such formulations may be, for example, in the form of tablets and / or lozenges manufactured using conventional methods and may contain, for example, from 0.1% to about 20% (w / w) of the active ingredient, the remainder comprising an orally soluble and / or degradable composition, and optionally one or more additional ingredients described herein. Alternatively, formulations suitable for buccal administration may comprise a powder and / or an aerosolized and / or atomized solution and / or suspension containing the active ingredient. Such powdered, aerosolized and / or aerosolized formulations, when dispersed, may comprise an average particle size and / or droplet size in the range of about 0.1 nm to about 200 nm, and may further comprise any one or more of the additional ingredients described herein.

[0210] The appropriate dose and dosage to be administered to a subject will be determined by factors including, but not limited to, the particular therapeutic rAAV composition, the disease symptoms and their severity, the identity of the subject requiring treatment (e.g., weight, sex, age), and can be determined according to the particular circumstances surrounding the case, including, for example, the particular agent being administered, the route of administration, the condition being treated, and the subject or host being treated.

[0211] The amount of AAV composition and the administration time of such composition are within the scope of a person skilled in the art who has the benefit of the present teachings.However, in some embodiments, the administration of a therapeutically effective amount of the disclosed composition can be achieved by a single administration, such as a single injection of a sufficient number of infectious particles to provide therapeutic benefit to the patient undergoing such treatment.This is made possible, at least in part, by the fact that certain target cells (e.g., neurons) do not divide, eliminating the need for multiple or chronic administrations.

[0212] In some embodiments, it is advantageous to provide multiple or continuous administrations of the AAV vector composition over a relatively short or long period of time, as may be determined by the physician overseeing the administration of such compositions. For example, the number of infectious particles administered to a mammal may be about 10 to 20, either given as a single dose or divided into two or more administrations as may be required to achieve treatment of the particular disease or disorder being treated. 7 , 10 8 , 10 9 , 10 10 , 10 11 , 10 12 , 10 13, or even more infectious particles / ml. Indeed, in certain embodiments, it may be desirable to administer two or more different AAV vector compositions, alone or in combination with one or more other therapeutic agents, to achieve the desired effect of a particular therapeutic regimen. In various embodiments, the daily dosage and unit dosage will vary depending on many variables, including, but not limited to, the activity of the therapeutic rAAV composition used, the disease or condition being treated, the mode of administration, the requirements of the individual subject, the severity of the disease or condition being treated, and the judgment of the physician.

[0213] The targeting peptides described herein can be used to generate rAAVs with enhanced CNS tropism using capsid proteins from different AAV serotypes (e.g., AAV9 and AAV1). In some embodiments, this can advantageously provide for administration of two or more different AAV vector compositions without inducing an immune response in a subject.

[0214] The frequency of administration of rAAV virus can vary.For example, rAAV virus can be administered to subject about once a week, about once every two weeks, about once a month, about once every six months, about once a year, about once every two years, about once every three years, about once every four years, about once every five years, about once every six years, about once every seven years, about once every eight years, about once every nine years, about once every ten years or about once every fifteen years. In some embodiments, the rAAV virus is administered to a subject at most about once per week, at most about once per two weeks, at most about once per month, at most about once per six months, at most about once per year, at most about once per two years, at most about once per three years, at most about once per four years, at most about once per five years, at most about once per six years, at most about once per seven years, at most about once per eight years, at most about once per nine years, at most about once per ten years, or at most about once per fifteen years.

[0215] Disclosed herein are kits comprising the compositions disclosed herein. Also disclosed herein are kits for treating or preventing a disease or condition of the CNS, PNS, or a target organ or environment (e.g., CNS). In some examples, the disease or condition is cancer, a pathogen infection, a neurological disease, a muscular disease, or an immune disorder such as those described herein. In one embodiment, the kit can include a therapeutic or prophylactic composition that includes a composition of an effective amount of rAAV particles that encapsidate a heterologous nucleic acid provided herein and a rAAV capsid protein of the present disclosure. In another embodiment, the kit can include a therapeutic or prophylactic composition that includes an effective amount of cells modified by the rAAV described herein ("modified cells") in a unit dosage form that expresses a therapeutic nucleic acid. In some embodiments, the kit includes a sterile container that can contain a therapeutic composition. Such a container can be a box, an ampoule, a bottle, a vial, a tube, a bag, a pouch, a blister pack, or other suitable container form known in the art. Such containers can be made of plastic, glass, laminated paper, metal foil, or other material suitable for holding agents.

[0216] In some embodiments, the rAAV is provided with instructions for administering the rAAV to a subject having or at risk of developing a disease or condition. The instructions may generally include information regarding the use of the composition for the treatment or prevention of the disease or condition.

[0217] The kit may include allogeneic cells. In some embodiments, the kit includes cells that can include genomic modifications. In some embodiments, the kit includes "off-the-shelf" cells. In some embodiments, the kit includes cells that can be expanded for clinical use. In some embodiments, the kit includes contents for research purposes.

[0218] In some embodiments, the instructions include at least one of the following: a description of the therapeutic rAAV composition; dosing schedules and administration for treatment or prevention of a disease or condition disclosed herein; cautions; warnings; instructions; adverse reactions; overdose information; adverse reactions; animal pharmacology; clinical studies; and / or references. The instructions can be printed directly on the container (if present), as a label affixed to the container, or as a separate sheet, pamphlet, card, or folder supplied in or with the container. In some embodiments, the instructions provide steps for administering the rAAV to a subject alone. In some embodiments, the instructions provide a procedure for administering rAAV to a subject at least about 1 hour (hr), 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, 24 hours, 25 hours, 26 hours, 27 hours, 28 hours, 29 hours, 30 hours, or up to 2 days, 3 days, 4 days, 5 days, 6 days, or 7 days or before administration of an additional therapeutic agent disclosed herein. In some examples, the instructions provide that the rAAV is formulated for intravenous injection. In some examples, the instructions provide that the rAAV is formulated for intranasal administration. EXAMPLES

[0219] Working Example Certain aspects of the above-described embodiments are disclosed in further detail in the following examples, which are not intended to limit the scope of the disclosure in any way. Example 1 material and method

[0220] The following experimental materials and methods were used in Examples 2 and 3 described below. Plasmids

[0221] AAV capsid variants were subcloned into pUCmini-iCAP-PHP.B backbone (Addgene ID: 103002). The ssAAV genomes used were pAAV:CAG-mNeonGreen (Addgene ID: 99134) and pAAV:CAG-2xNLS-EGFP (equivalent version with one NLS: Addgene ID: 104061), as described in the figure and legend. Receptor candidate plasmids were purchased from GenScript. All selected open reading frame (ORF) clones were introduced into pcDNA3.1+ / C-(K)-DYK backbone, except for Lynx1 in pcDNA3.1. AAV capsid library was amplified from pCRII-9Cap-XE plasmid and subcloned into rAAV-DCap-in-cis-Lox2 plasmid for transfection with AAV2 / 9 REP-AAP-DCap. animal

[0222] All animal procedures were approved by the California Institute of Technology Institutional Animal Care and Use Committee (IACUC) and followed all relevant ethical regulations. C57BL / 6J (000664), BALB / cJ (000651), 129S1 / SvlmJ (002448), CBA / J (000656), DBA / 2J (000671), NOD / ShiLtJ (001976), Syn1-Cre (3966), GFAP-Cre (012886), Tek-Cre (8863) and Olig2-Cre (025567) mouse strains were purchased from Jackson Laboratory (JAX). Heterozygous Car4 knockout mice (008217) were frozen and collected by JAX and bred at Caltech to generate homozygous WT / WT and KO / KO animals. Male mice aged 6–8 weeks were injected intravenously into the retro-orbital sinus with rAAV. Mice were randomly assigned a specific rAAV during testing for transduction phenotypes. Experimenters were not blinded to any of the experiments performed. AAV vector production

[0223] AAV packaging and purification were performed as previously described. Briefly, rAAV was produced by triple transfection of HEK293T cells (ATTC, CRL-3216) using polyethylenimine. Media was harvested 72 and 120 hours after transfection. Virus was precipitated in 40% polyethylene glycol in 2.5 M NaCl. Virus was resuspended and diluted with 500 mM NaCl, 40 mM Tris, 10 mM MgCl2, and 100 U mL -1 The virus was combined with the post-transfection cell pellet in salt-active nuclease (ArcticZymes, 70910-202) for 120 h at 37 °C. The resulting lysate was extracted from an iodixanol (Cosmo Bio USA, OptiPrep, AXS-1114542) step gradient following ultracentrifugation. Purified virus was concentrated and titered by quantitative PCR after buffer exchange into phosphate-buffered saline (PBS). AAV vector administration, tissue processing, and imaging

[0224] AAV vectors were injected at 1 × 10 11 vg or 3×10 11 vg doses were administered intravenously to adult male mice by retro-orbital injection. Three weeks after expression, mice were anesthetized with Euthasol (sodium pentobarbital and sodium phenytoin solution, Virbac AH) and transcardially perfused with approximately 50 mL of 0.1 M PBS, pH 7.4, followed by another 50 mL of 4% paraformaldehyde (PFA) in 0.1 M PBS. Organs were then harvested and post-fixed overnight at 4°C in 4% PFA, followed by washing and storage at 4°C in 0.1 M PBS and 0.05% sodium azide. Finally, brains were cut into 100 μm sections on a Leica VT1200 vibratome. Images were acquired with a Zeiss LSM880 confocal microscope using a Plan-Apochromat ×10 0.45 M27 (working distance, 2.0 mm) objective and processed with Zen Black 2.3 SP1 (Zeiss) and ImageJ software. Single-cell RNA sequencing analysis

[0225] Analysis was performed on an existing C57BL / 6J cortical single-cell RNA sequencing dataset with custom scripts in Python 3.7.4 using a custom forkoff of scVI v0.8.1 and Scanpy v1.6.0 as previously described. Briefly, droplets that passed quality control were classified as "neuronal" or "non-neuronal" using a trained scANVI cell type classifier, and only cells above a false discovery rate threshold of 0.05 after correction for multiple comparisons were retained. Non-neuronal cells were further subtyped using a trained scVI model and clustered based on a latent space learned using the Leiden algorithm implemented in Scanpy. Endothelial cell clusters were assigned if they were positive for all marker genes for that cell subtype. Membrane proteins were filtered by the Uniprot keyword "cell membrane". Differential expression scores were calculated in Scanpy. Immunofluorescence

[0226] Immunofluorescence experiments were performed in HEK293T cells to label transiently transfected receptors such as Ly6a (Abcam ab51317, 1:200 dilution), Ly6c1 (Abcam ab15627, 1:200 dilution) and Car4 (Invitrogen PA5-47312, 1:40 dilution). HEK293T cells were seeded at 80% confluency in 6-well plates and maintained at 37°C and 5% CO2 in Dulbecco's Modified Eagle Medium (DMEM) supplemented with 5% fetal bovine serum (FBS), 1% non-essential amino acids (NEAA), and 100U / mL penicillin-streptomycin. Membrane-associated receptor candidates were transfected by polyethylenimine (PolySciences #23966). Cells were seeded in 24-well plates on Neuvitro Poly-D-lysine coated sterile German glass coverslips (Fisher Scientific #NC0343705) 24 hours after transfection, then attached and fixed in 4% paraformaldehyde. Coverslips were blocked with 1× Tris-buffered saline (TBS) containing 3% bovine serum albumin (BSA) for 30 minutes and incubated in primary antibodies in 1× TBS, 3% BSA, and 0.05% Triton® X-100 for 60 minutes at ambient temperature. Coverslips were washed three times with 1× TBS and then incubated with secondary antibodies (Ly6a and Ly6c1: Invitrogen A-21247, 1:1000 dilution; Car4: Invitrogen A-21432, 1:1000 dilution) in the same medium for 60 minutes. Coverslips were mounted onto slides using Diamond Antifade Mounting Media containing DAPI (Invitrogen P36931). Fluorescence microscopy images were captured with a confocal laser scanning microscope (LSM880, Carl Zeiss, USA). Cell culture characterization of rAAV vectors

[0227] HEK293T cells were seeded in 6-well plates at 80% confluency and incubated with 5% FBS, 1% NEAA and 100 U mL -1The cells were maintained at 37°C, 5% CO2 in DMEM supplemented with penicillin-streptomycin. Candidate membrane-associated receptors were transiently expressed in HEK293T cells by transfecting 2.53 μg of plasmid DNA into each well. Receptor-expressing cells were transferred to 96-well plates at 20% confluency and maintained at 37°C, 5% CO2 in FluoroBrite™ DMEM supplemented with 0.5% FBS, 1% NEAA, 100 U mL-1 penicillin-streptomycin, 1×GlutaMAX and 15 μM HEPES. Cells expressing each candidate receptor were transfected with 1E9 v.g. well. -1 and 5E8v.g.well -1 Plates were imaged 24 hours after transduction on a Keyence BZ-X700 using a 4x objective and NucBlue™ Live ReadyProbes™ reagent (Hoechst33342) to autofocus each well. Cell culture fluorescence imaging quantification

[0228] All image processing was performed using a custom Python image processing pipeline. Briefly, the area of ​​cells was determined in both bright field and signal images. The percentage of transduced cells and the brightness per transduced area were determined from these images.

[0229] First, background subtraction was performed on the brightfield images by applying a Gaussian blur (skimage.filters.gaussian, sigma=30, truncate=0.35) and subtracting the product from the original brightfield image. In the brightfield images, cells were silhouetted by a ramp producing both bright and dark edges. Histogram-based thresholding was applied to these images to determine the light and dark regions in the brightfield image, which can be combined to create a mask of cell edges in the image. Cells can be filled by applying skimage.morphology.closing, which ran a template over the image to fill contiguous regions (skimage.morphology.disk, radius=2). The total area of ​​the cells in the brightfield image can then be determined by summing all the pixels in the mask.

[0230] Background subtraction was performed on the signal images by applying a Gaussian blur (skimage.filters.gaussian, sigma=100). Subtracting the product of the Gaussian blur from the original signal images produced images with minimal variation in background intensity. Histogram-based thresholding was applied to these images to identify background intensity in brightfield images and to create a mask of bright areas in images containing transduced cells. Noise was removed from the mask using skimage.morphology.remove_small_objects(min_size=5). From this, the total area of ​​transduced cells was determined by summing all pixels in the mask.

[0231] After this segmentation, the percentage of transduced cells was determined by taking the ratio of the signal area to the total cell area. The total brightness of the transduced cells was determined by multiplying the mask by the original image and summing all pixel intensities in the product image. This value was then divided by the total area of ​​the transduced cells to determine the brightness per transduced area. Receptor protein production

[0232] Ly6a-Fc was produced in Expi293F suspension cells grown in Expi293 expression medium (Thermo Fisher Scientific) in a 37°C, 5% CO2 incubator with shaking at 130 rpm. Transfection was performed using Expifectamine according to the manufacturer's instructions (Thermo Fisher Scientific). After harvesting the cell conditioned medium, 1 M Tris (pH 8.0) was added to a final concentration of 20 mM. Ni-NTA agarose (QIAGEN) was added to approximately 5% conditioned medium volume. 1 M sterile PBS, pH 7.2 (GIBCO) was added to approximately 3× conditioned medium volume. The mixture was stirred overnight at 4°C. The Ni-NTA agarose beads were collected in a Büchner funnel and washed with approximately 300 mL of protein wash buffer (30 mM HEPES, pH 7.2, 150 mM NaCl, 20 mM imidazole). The beads were transferred to an Econo-Pak chromatography column (Bio-Rad) and the protein was eluted with 15 mL of elution buffer (30 mM HEPES, pH 7.2, 150 mM NaCl, 200 mM imidazole). The protein was concentrated using an Amicon Ultracel 10K filter (Millipore). The protein concentration was determined by measuring the absorbance at 280 nm using a Nanodrop2000 spectrophotometer (Thermo Fisher Scientific). Surface Plasmon Resonance (SPR)

[0233] SPR was performed using a Sierra SPR-32 (Bruker). Ly6a-Fc fusion protein in HBS-P+ buffer (GE Healthcare) was immobilized on a Protein A sensor chip with a capture level of approximately 1200–1500 response units (RU). 12 vgmL -1 10 μl of 2-fold dilutions of rAAV starting at -1 The injections were performed at a flow rate of 100 s with a contact time of 240 s and a dissociation time of 600 s. After each cycle, the Protein A sensor chip was regenerated with 10 mM glycine pH 1.5. Rate data were double-baseline subtracted. Automated pairwise peptide receptor analysis for screening of engineered AAV (APPRAISE-AAV)

[0234] FASTA format files containing the target receptor amino acid sequence (mature protein portion only) as well as peptide sequences corresponding to amino acids 587-594 (wild type AAV9 VP1 index) from two AAV capsids of interest were used for structure prediction using a batch version of ColabFold (alphafold-colabfold2.1.14), a cloud-based implementation of multiple sequence alignment, and AlphaFold2 multimer. ColabFold Jupyter notebooks were run in a Google Colaboratory session using a GPU (NVIDIA Tesla V100 SXM2 16GB; the same model on the GPU was found to yield the most consistent results). AlphaFold2-multimer-v2 was selected as the default AlphaFold version unless otherwise stated. Each model was recycled three times, generating 10 models from each competition. Models were quantified using custom scripts with PyMol (version 2.3.3) to determine the total number of atoms at the interface (

number

number

number

number

[0235] Here, each term is defined as follows:

number

[0236] The average numbers of this metric across replicates were used to form a matrix and plot a heatmap. Peptides in the heatmap were ranked by the total number of competitions each peptide won minus the total number of competitions it lost (those with a p-value of >0.05 in a one-sample Student's t-test).

number

[0237] The peptide receptor structures were modeled using a similar procedure as described in the APPRAISE-AAV section, but using only a single peptide of interest in the input file to achieve higher accuracy.

[0238] An AAV trimer-receptor complex model was created using an integrated structural modeling method (Figure 13A). A trimer at the AAV three-fold symmetric interface was selected as the minimal complete binding interface with the putative receptor that could reproduce the entire viral particle while optimizing computational efficiency. First, a peptide receptor model was created by modeling a 15mer peptide sequence between residues 587 and 594 (both wild-type AAV9 VP1 index) from the AAV variant of interest in complex with the target receptor as described above. The trimer model of the AAV variant of interest was then modeled using AlphaFold2 multimers. The two residues with the highest confidence scores (pLDDT scores) in the 15mer peptide, Pro5' and Phe6', of the peptide receptor model were structurally aligned to the corresponding residues on the first chain of the trimer model. A crude combination model was then generated by combining the receptor and two high-confidence AAV residues from the peptide receptor model with the remaining AAV residues from the trimer model. Then, two loops between Pro5' and Phe6' and the high-confidence AAV9 backbone in the crude synthetic model (corresponding to residues 588-(588+)4' and residues (588+)7'-590, respectively) were individually remodeled using RosettaRemodel from the Rosetta software bundle (release 2018.48.60516). Finally, these remodeled loops were merged to generate the final model. The pLDDT scores of each residue from the original AlphaFold2 output were used to color the image of the final model. Choosing M-CREATE for PHP.eC

[0239] AAV capsid libraries were generated in vivo, administered, and harvested for next generation sequencing as previously described. Briefly, initial libraries were generated by pooling three amino acid NNK substitutions scanning from AAV9 587 through a 7mer insertion to AAV9 position 590 in AAV-PHP.C1, C2, C3, and C4 (Figure 5A). A custom designed synthetic round 2 library containing degenerate codon overlaps of 5515 capsid variants identified from the round 1 library after selection and spike-in controls was synthesized in equimolar ratios by Twist Biosciences. To prevent capsid mosaicism, only 10 ng of assembled library was transfected per 150 mm dish of 293T producer cells, and assembled capsids were purified 60 hours after transfection. Round 1 libraries were transfected at 5 × 10 per mouse in Syn-Cre. 10 vg, and the round 2 library was transfected into Syn-Cre, GFAP-Cre, Tek-Cre, Olig2-Cre, wild-type C57BL / 6J, and wild-type BALB / cJ mice at 5 × 10 per mouse. 11 Retroorbital injection was performed with vg.

[0240] Two weeks after injection, mice were euthanized and all organs, including the brain, were collected, flash frozen on dry ice, and stored at -80°C. Frozen tissues were homogenized using a Beadbug homogenizer (Homogenizer, Benchmark Scientific, D1032-15, D1032-30, D1033-28) and rAAV genomes were Trizol extracted. Purified rAAV DNA (Zymo DNA Clean and Concentrator Kit D4033) was amplified by PCR using Cre-dependent primers and flow cell adapters were added around the diversified regions for next-generation sequencing. NGS data were aligned and processed as previously described to extract round 1 variant sequence counts and round 2 variant enrichment scores. Example 2 Identification of Carbonic Anhydrase IV and Mouse Restricted Ly6c1 as a Novel Target for Crossing the Blood-Brain Barrier

[0241] This example demonstrates the identification of carbonic anhydrase IV and mouse-restricted Ly6c1 as two novel targets for crossing the blood-brain barrier. By screening a curated pool of 40 candidate receptors selected for crossover between CNS expression levels and endothelial cell specificity, we identified Ly6c1 and carbonic anhydrase IV as molecular receptors for enhanced BBB crossing of 10 Ly6a-independent engineered AAVs (as well as the Ly6a-dependent PHP.N). These findings will enable more efficient allocation of NHPs and inform future directed evolution library design, enabling receptor-guided engineering for direct human protein interactions. Identification of engineered AAVs that do not utilize Ly6a

[0242] Ly6a is the receptor responsible for the enhanced CNS tropism of PHP.B and PHP.eB in mice. One strain-specific SNP disrupts its GPI-anchored membrane localization (Figure 1A). Previously, we applied the M-CREATE directed evolutionary selection platform to a library of AAV9 variants (containing a seven amino acid insertion at position 588 in the capsid variable region VIII) to identify a family of engineered AAVs with diverse CNS tropism and shared sequence motifs represented by their origin member, AAV-PHP.B (Figure 1B). The enhanced CNS potency of the variants was absent in BALB / cJ mice, a phenomenon explained by their common dependency on Ly6a for BBB crossing. Recently, multiple engineered AAVs outside the PHP.B sequence family were identified that retained enhanced CNS tropism in BALB / cJ mice. Before attempting to deorphanize these AAVs, their independence of Ly6a was first confirmed.

[0243] To directly probe potential Ly6a binding interactions, we performed surface plasmon resonance (SPR). To further ensure detection of weaker interactions, Ly6a was dimerized by fusion to Fc and immobilized at high density on a protein A chip. Each AAV analyte was tested over a range of concentrations (Figure 1C). As expected, AAV9 showed no evidence of binding at any concentration, and all PHP.B sequence family members showed strong binding interactions with Ly6a. Although the exact affinity could not be determined due to avidity and mass transport effects, the interaction profile was consistent with subnanomolar affinity. Conversely, all BALB / cJ-enhanced artificial AAVs were indistinguishable from AAV9 and showed no detectable interactions with Ly6a. CNS potency of Ly6a-independent engineered AAVs across genetically diverse mouse strains

[0244] To characterize strain-specific differences in the CNS potency of BALB / cJ-enhanced AAVs, we performed an exploratory evaluation using some of them in multiple genetically diverse mouse strains (Figures 2A-C and ​and8A). 8A.1.1.2.1.1.1.1.1.1.1.1.1.1.1.1.0 ... 11 vg were injected retro-orbitally. Tissues were harvested and imaged 3 weeks after injection. The thalamus was chosen for comparison as this brain region was potently targeted by all AAVs tested. As expected, given their Ly6a interactions, PHP.eB and PHP.N showed enhanced potency in 129S1 / SvlmJ and DBA / 2J mouse strains that expressed membrane-localized Ly6a, and greatly reduced potency in CBA / J and NOD / ShiLtJ mouse strains that expressed GPI-disrupted Ly6a. However, Ly6a-independent AAVs showed distinct patterns of enhanced infectivity. Selective AAV strain-mouse strain combinations were investigated in both sexes, and similar trends were observed across strains (Figure 8B). The potentially higher potency observed in female mice could result from batch-to-batch variation or gender-related differences in AAV potency.

[0245] Previously, we have used genetic techniques to identify the Ly6a receptor. Following this approach to identify the receptor responsible for enhancing CNS transduction of Ly6a-independent vectors, we crossed C57BL / 6J and CBA / J mice and tested the vector PHP.C3 in their offspring (F1), anticipating an intermediate phenotype if the receptor were inherited similarly to Ly6a. Both parental strains and F1 adults were transfected with 3 × 10 per animal. 11 vg was injected retro-orbitally. After 3 weeks, tissues were harvested and imaged. Surprisingly, at this higher dose, PHP.C3 demonstrated robust CNS infectivity in all three populations (Figure 8C). This dose-dependence suggested more subtle mechanistic differences with the presence or absence of a single receptor, leading to the application of a different approach. Establishment of cell culture screening for putative receptors of artificial AAV

[0246] Receptors that engineered AAVs can select for efficient BBB crossing are likely to be highly expressed and highly specific to brain endothelial cells. Therefore, we analyzed single-cell RNA sequencing data previously collected from dissociated C57BL / 6J brain tissue (Figure 3A). Gene expression levels and differential expression were investigated within the CNS endothelial cell cluster compared to all other CNS cell type clusters. Genes were filtered to select only genes annotated as localized to the plasma membrane in Uniprot before calculating their endothelial cell differential expression scores in Scanpy. These scores were then plotted against the average abundance of each transcript, revealing a long tail of highly expressed and highly specific CNS endothelial membrane proteins. Encouragingly, Ly6a appeared at the far end of this tail. From this analysis, we selected a panel of 40 abundant and specific candidate receptors (Table 3). [Table 3-1] [Table 3-2]

[0247] We observed that expression of membrane-localized Ly6a in HEK293 cells selectively improved the potency of PHP.eB infection compared to AAV9 at low multiplicity of infection (MOI), with a marked increase in the extent of infection and brightness of infected cells (Figure 9A). This property is likely conserved among BBB-crossing receptors. This behavior therefore formed the basis of a receptor transient overexpression screen (Figure 3B and Figure 3C). The C57BL / 6J coding sequence for each of the 40 candidate receptors was cloned into a mammalian expression plasmid and tested against AAV engineered in triplicate at two different doses (Figure 3A and Figure 3D). PHP.eB paired with Ly6a served as a positive control.

[0248] As expected, all members of the PHP.B sequence family showed a significant boost in infectivity in Ly6a-transfected cells compared to non-transfected cells, while Ly6a-independent AAVs functioned similarly under both conditions (Figures 3D, 3E, and 9B). Interestingly, the infectivity of all Ly6a-dependent capsids was enhanced to a similar extent (Figure 10B). Identification of Ly6c1 and Car4 as receptors for BBB crossing of Ly6a-independent engineered AAV

[0249] A boost in infectivity was observed for all tested Ly6a-independent AAVs with the novel receptor (Figure 3D). Surprisingly, given their distinct sequence families and the strain-dependent pattern of CNS potency at low doses, all of the initial Ly6a-independent AAVs responded to the same candidate receptor, Ly6c1 (Figures 3D-G and 9B). Furthermore, despite the Ly6a-dependent pattern of CNS infectivity across mouse strains, in Ly6c1-transfected cells, PHP.N also showed enhanced infectivity. At higher doses, PHP.N outperformed both AAV9 and PHP.eB in CBA / J mice that expressed GPI-disrupted Ly6a (Figures 11A and 11B). Although polymorphisms in Ly6c1 existed across mouse strains (as shown by published analyses of 36 mouse strains for which whole genomes were available), none of these polymorphisms correlated with the pattern of CNS potency of any of the eight Ly6c1-interacting AAVs. Furthermore, unlike Ly6a, no polymorphisms were predicted that would disrupt GPI anchoring of Ly6c1 to the plasma membrane using PredGPI. To determine the specificity of the Ly6c1 interaction, follow-up screening was performed with additional closely related CNS-expressed Ly6 superfamily members. No cross-reactivity of Ly6c1-dependent AAVs with other Ly6 proteins was observed (Figure 3G). CAP-B10 and CAP-B22, which have seven amino acid substitutions in the capsid variable region IV and showed enhanced potency in adult marmosets, did not show any additional receptor interactions in either the above screen or a third screen with marmoset CNS-expressed Ly6 family members (Figure 10C) that would explain their NHP tropism. Furthermore, Ly6-interacting AAVs did not cross-react with the recently reported human Ly6S, a close relative of mouse Ly6a (Figure 3G).

[0250] The Ly6 follow-up screen was expanded to include a second set of previously identified engineered AAVs (9P), yielding additional Ly6a- and Ly6c1-interacting AAVs (Figure 3G). However, 9P31 and 9P36 did not show enhanced infectivity with any of the Ly6 proteins in the panel and were therefore tested in a full receptor screen (Figure 3D). Both 9P31 and 9P36 showed boosted infectivity with the GPI-linked enzyme Car4 (Figure 3D and Figure 9B). This interaction was specific for Car4 among membrane-bound carbonic anhydrases (Figure 3G). Similar to Ly6c1, polymorphisms in Car4 across mouse lineages were not predicted to affect GPI anchoring to the plasma membrane. Unlike mouse-restricted Ly6a and Ly6c1, Car4 is conserved across vertebrates, including non-human primates and humans. Thus, we verified the screening results by comparing the results with those of Car4 knockout mice (B6.129S1-Car4 tm1Sly WT / J, Jackson labs strain #008217) was used to confirm in vivo expression of Car4. Immunofluorescence confirmed that Car4 was strongly expressed throughout the brain vasculature of homozygous WT / WT mice and completely absent in KO / KO mice (Figure 4A). 3 × 10 per animal 11 When 9P31 and 9P36 were administered 100 μg / kg / day, PHP.eB, 9P31, and 9P36 were all strongly expressed in both the brain and liver of wild-type mice (Figure 4B). Under the same conditions in KO / KO mice, both 9P31 and 9P36 completely lost their enhanced CNS tropism, whereas PHP.eB was unaffected (Figure 4C and Figure 11B). On the other hand, liver tropism was uncoupled from this effect, and all three viruses showed strong transduction in KO / KO mice. The difference in potency of 9P31 and 9P36 in the periphery of KO / KO mice may be due to pharmacokinetic effects that no longer efficiently access the CNS.

[0251] Notably, all AAVs tested showed a moderate infectivity boost in cells transfected with Slco1c1 (also known as Oatp1c1), an integral membrane anion transporter (Figure 3D). However, unlike cells transfected with other potential receptors, the mNeonGreen signal in Slco1c1-transfected cells was weak and diffuse, extending beyond the cell border (Figure 9C), suggesting transgene export or a cell health phenotype. The universality of this effect and the specificity of Slco1c1 expression in the brain suggested a possible role in the weak BBB transcytosis of parental AAV9. None of the other 36 candidate receptors provided a significant infectivity boost for any of the 16 engineered AAVs screened. Example 3 Receptor-binding peptides and engineered AAVs for BBB crossing

[0252] This example demonstrates the design of receptor-binding peptides and engineered AAVs containing receptor-binding peptides and illustrates their enhanced efficacy in crossing the BBB. Directed evolution of improved Ly6c1-dependent capsids

[0253] Directed evolution is a powerful method to generate biomolecules with improved fitness for desired properties despite an incomplete understanding of the underlying biological system. Importantly, the results of directed evolution libraries can be used to unlock new biomolecules by probing the mechanism of action of molecules with evolved properties. This paradigm of reverse engineering directed evolution has been applied to the wealth of accumulating data obtained from applying selective pressures to AAV libraries for CNS enrichment following systemic administration.

[0254] We demonstrated proof-of-concept for receptor-targeted evolution. To this end, the mouse receptor Ly6c1 (versus human Car4) was chosen due to (1) strains with distinct BBB differences, e.g., Ly6a, and (2) the rapid availability of diverse Cre transgenic animals for M-CREATE selection, which was not available for Car4 in other species. Furthermore, given the mixed background of preclinical animal models, it remained important to have mechanistically distinct gene delivery vectors for rodents as well. Thus, a single optimized capsid was engineered for broad adoption as a research tool in the GPI-disrupted Ly6a mouse strain, an unmet need, using the previously developed M-CREATE method for AAV capsid-directed evolution (Figure 5A-D). This method used Cre-dependent AAV genome recovery from desired tissues and cell types after in vivo selection in Cre-transgenic mice, allowing deep characterization of selected capsids across various cell types and tissues.

[0255] Using M-CREATE, we constructed a scanning trimer replacement capsid library in chemically diverse Ly6c1 interacting variants PHP.C1, PHP.C2, PHP.C3 and PHP.C4. These libraries were pooled for two rounds of selection in Syn-Cre mice (Figure 5A). In the second round of selection, we also included Olig2-Cre, Tek-Cre and GFAP-Cre mice, as well as wild-type C57BL / 6J and BALB / cJ mice, allowing potential differences in enhancement between these strains or cell types to be detected during selection between variants (Figure 5B). Interestingly, PHP.C2 variants dominated both selection rounds in the C57BL / 6J background (Cre-dependent or independent), whereas PHP.C1 variants dominated round 2 Cre-independent selection in BALB / cJ (Figure 12). After selection, high-performing variants were individually generated and characterized. AAV-PHP.eC (variant 19), evolved from PHP.C1, retained Ly6c1 interaction in cell culture (Figure 5C) and outperformed PHP.C2 in multiple mouse strains with membrane-disrupted Ly6a (Figure 5D). Thus, PHP.eC provided a powerful tool for transgene delivery in mouse strains without membrane-localized Ly6a.

[0256] Nine capsids were found to interact with the same receptor, Ly6c1, although differences in their capsid insertion sequences and patterns of CNS potency across genetically diverse mouse strains at low doses suggested potentially diverse mechanisms for crossing the BBB. Potency differences across mouse strains may be highly dose-dependent, as seen with PHP.C3 and PHP.N. This suggests that in some cases, cell culture screens may be sensitive to interactions that may become functionally relevant in vivo only at higher doses. Several Ly6c1 polymorphisms were present across mouse strains, but similar to observations in Ly6a-dependent AAVs, no clear pattern emerges between mutational variants and strain potency of AAV. Furthermore, unlike Ly6a, none of the sequence polymorphisms were predicted to interfere with Ly6c1 GPI anchoring and thus membrane localization. Ly6c1 expression levels were also consistently high across inbred mouse strains, but significantly lower in recent wild-type mouse strains. This suggests that the low-dose efficacy patterns observed here may instead result from differences in how the individual Ly6c1-binding footprints of each AAV are influenced by strain-dependent sequence polymorphisms, or from differences in unidentified off-target interactions. An AlphaFold2-based method for in silico identification of receptor-binding peptides and engineered AAV binding poses

[0257] Having identified a panel of receptor-AAV capsid pairings, we used protein structure prediction methods to generate binding poses of engineered AAVs and their newly identified receptors. We applied AlphaFold2-based computational methods for APPRAISE-AAV. The APPRAISE-AAV in silico method can be applied to any existing engineered capsid library dataset to look for capsid variants that are likely to interact with a selected target receptor, including carbonic anhydrase IV (e.g., Car4). The modeling pipeline can also provide high-confidence binding models of AAV-receptor complexes that have proven difficult to elucidate structurally. AAV is used as an example to demonstrate this in silico approach, but the APPRAISE methodology is not limited to AAV. Furthermore, the pipeline for generating complete AAV trimeric complex structures can be easily used to guide the translation of engineered peptide insertions identified by AAV directed evolution into other protein modalities.

[0258] Specifically, the APPRAISE-AAV in silico method used AlphaFold2 to place surface-exposed peptides (AA587-594) spanning mutagenic insertions from two different AAV variants competing to interact with a potential receptor (Figure 6A). This included the minimal peptide encompassing the solvent-exposed residues of capsid variable region VIII. A combination of physical and geometric scoring parameters, including calculations of interfacial energy, binding angles and binding pocket depth, was used to generate a peptide competition metric. Results from these individual pairwise competitions can be assembled into a larger matrix that ranks the set of AAV capsid insertion peptides according to their receptor-binding probability, which is encoded into the AlphaFold2 neural network. When applied to Ly6a and newly identified receptors, experimentally validated Ly6a, Ly6c1 and Car4 insertion peptides were elevated to the top of the respective rankings (Figure 6B-C). However, some false negatives were also observed, such as 9P08 containing Ly6a or 9P36 containing Car4.

[0259] In addition to predicting whether the peptide would bind to the receptor, the structural details of the binding interaction were also computationally explored. Binding poses were generated by pairing the apical AAV insert peptide with its receptor. Each pairing was validated by repeating the cell culture screen with receptors containing point mutations hypothesized to disrupt high-confidence regions of the binding interface (as determined by per-residue estimated model confidence pLDDT scores and consistency between replication models) in these predicted poses. The PHP.eB peptide was predicted to insert into the groove of Ly6a and form strong interactions with several Ly6a residues (Figure 6E) at Pro5' and Phe6' (Figure 6D). Thus, introducing a mutation into this groove, Ly6a Ala58Arg, was found to disrupt the infectivity enhancement of PHP.eB with the wild-type receptor. This experimental result further strengthened the confidence in the in silico APPRAISE-AAV ranking.

[0260] To obtain a complete picture of AAV-receptor interactions, we modeled the PHP.eB insert peptide and Ly6a receptor complex in association with the three-fold symmetric spike of the AAV capsid. This structure was challenging for standard modeling tools due to the large size of the AAV capsid (~200 kDa per trimer), as well as the often weak dynamic binding interactions between the engineered capsid and the receptor (µM affinity possible without avidity). AlphaFold2 was unable to capture the direct contact between the full-length PHP.eB capsid and Ly6a in either monomeric or trimeric receptor configurations (data not shown). To address this challenge, an integrated structural modeling pipeline was developed. In this pipeline, an initial model of the AAV capsid trimer predicted using AlphaFold2-multimer was structurally aligned with the AlphaFold2-predicted peptide-receptor complex model through RosettaRemodel optimization of high-confidence Pro5' and Phe6' residues of the peptide insert, as well as the connecting peptide residues in relation to the AAV capsid three-fold symmetric spike (Figure S13A). This fully bound model (Figure S6E) provided a snapshot of the dynamic interactions that have thus far proven amenable to high-resolution structural characterization.

[0261] The results of the PHP.eB-Ly6a model were consistent with the available experimental results. The root mean square deviation (RMSD) between the PHP.eB monomer model and the cryo-EM-based model (PDB ID: 7WQO) was 0.36 Å. The RMSD increased to 1.36 Å for the engineered loops of PHP.eB. The only high-confidence deviation from the cryo-EM structure of uncomplexed PHP.eB was the side chain of Phe6', which did not show significant electron density, indicating flexibility, but formed a stable interaction with Ly6a in the PHP.eB monomer model (Figure 13B, right). The high-confidence prediction of Pro5' and Phe6' was consistent with recent evidence showing that only the PFK trimer insertion was sufficient to obtain Ly6a binding. Although Ly6a can bind to any inserted loop of the trimer, further interactions induced steric clashes, favoring a ratio of one Ly6a per capsid trimer. Interestingly, the PHP.EB-Ly6a composite ensemble image, which was forced to include 60 bound copies of Ly6a, resembled a recently reported cryoEM map, whose analysis pipeline averaged over all 60 singly occupied binding sites to form a composite map (Figure 13C). The PHP.eB-Ly6a complex model showed that single copies of both the Ly6a domain and the AAVR PKD2 domain could bind simultaneously to the same 3-fold spike without clashing (Figure 13D), consistent with saturation binding experiments. Consistent with previous studies showing that Ly6a SNP D63G did not affect PHP.eB binding, residues were >10 Å from the PHP.eB peptide atoms in the PHP.eB-Ly6a complex model. The PHP.eB-Ly6a complex model included several interactions involving AAV insert neighboring residues, consistent with previous reports (Figure 6G).

[0262] These structural modeling methods were then applied to the newly identified receptor. Interestingly, unlike Ly6a and Car4, the predicted binding pose of the PHP.C2 peptide with Ly6c1 was found to vary depending on the version of AlphaFold-multimer used, with the v1 prediction matching closely with mutational data from cell culture infectivity assays (Figure 14A). Such complementarity between versions has been reported previously. In mouse Car4, the 9P31 peptide invaded the catalytic pocket of the enzyme (Figure 7A). The 9P31 tyrosine residue shared with 9P36 approaches the enzyme active site, while the diverse tryptophans of 9P31 find purchase in the auxiliary pocket (Figure 7B). This predicted binding pose was competitive with the binding site of Brinzolamide (PDB ID 3NZC), a broad spectrum carbonic anhydrase inhibitor prescribed for glaucoma. In cell culture infectivity assays, Brinzolamide showed dose-dependent inhibition of 9P31 and 9P36 potency, whereas PHP.eB was unaffected (Figure 7B). The smaller Brinzolamide bound deep to the catalytic core of Car4, where the side chains are mostly conserved between species (Figure 7C). However, the 9P31 peptide extended to the surface of the enzyme, where there was considerable sequence variance. Similarly, Brinzolamide bound to both mouse and human Car4, whereas 9P31 and 9P36 were specific for mouse Car4 (Figure 7D). Chimeric receptors that swapped the highly branched loop of the 9P31 binding site indicated that this region was necessary but not sufficient to control the potency of 9P31 and 9P36. A second potential Car4 binding site was also suggested by lower-ranked poses with 9P31 and 9P36, but mutagenesis experiments showed inconsistent effects (Figure 14B). Future rational engineering of new AAVs against species-appropriate CA4, aided by the APPRAISE-AAV method, is a promising new avenue for the generation of non-invasive vectors with enhanced CNS potency. Targeting CA4 may also find applications across diverse proteins and chemical modalities. In vivo experiments can be performed to further validate the engineering of human CA-binding AAVs with optimal BBB-crossing properties.

[0263] In at least some of the above-described embodiments, one or more elements used in an embodiment may be used interchangeably in another embodiment, unless such substitution is technically infeasible. Those skilled in the art will appreciate that various other omissions, additions and modifications may be made to the methods and structures described above without departing from the scope of the claimed subject matter. All such modifications and variations are intended to be included within the scope of the subject matter, as defined by the appended claims.

[0264] With respect to the use of substantially any plural and / or singular term herein, one of ordinary skill in the art can convert from plural to singular and / or from singular to plural as appropriate to the context and / or application. Various singular / plural permutations may be expressly set forth herein for clarity. As used herein and in the appended claims, "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Any reference to "or" herein is intended to encompass "and / or" unless otherwise specified.

[0265] In general, it will be understood by those skilled in the art that the terms used herein, and particularly in the appended claims (e.g., the body of the appended claims), are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to", the term "having" should be interpreted as "having at least", the term "includes" should be interpreted as "includes but not limited to", etc.). If a specific number of introduced claim recitations are intended, such intent will be explicitly set forth in the claim, and it will be further understood by those skilled in the art that, in the absence of such recitation, no such intent exists. For example, to aid in understanding, the following appended claims may include the use of the introductory phrases "at least one" and "one or more" to introduce the claim recitations. However, the use of such phrases should not be construed as meaning that the introduction of a claim recitation with the indefinite article "a" or "an" limits any particular claim that includes such an introduced claim recitation to embodiments that include only one such recitation, even if the same claim includes the introductory phrases "one or more" or "at least one" and an indefinite article such as "a" or "an" (e.g., "a" and / or "an" should be interpreted to mean "at least one" or "one or more"), and the same applies to the use of definite articles used to introduce claim recitations. Moreover, even if a particular number of introduced claim recitations is explicitly recited, one of ordinary skill in the art will recognize that such recitation should be interpreted to mean at least the recited number (e.g., a bare recitation of "two recitations" without any other modifiers means at least two recitations, or two or more recitations).Furthermore, when a convention similar to "at least one of A, B, and C, etc." is used, generally such configurations are intended in the sense that one of ordinary skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" includes, but is not limited to, systems having A only, B only, C only, A and B together, A and C together, B and C together, and / or A, B and C together, etc.). When a convention similar to "at least one of A, B, or C, etc." is used, generally such configurations are intended in the sense that one of ordinary skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" includes, but is not limited to, systems having A only, B only, C only, A and B together, A and C together, B and C together, and / or A, B and C together, etc.). It will be further understood by those skilled in the art that virtually any disjunctive word and / or phrase presenting two or more alternative terms, whether in the specification, claims, or drawings, should be understood to contemplate the possibility of including one of the terms, either of the terms, or both terms.

[0266] Furthermore, where features or aspects of the disclosure are described in terms of a Markush group, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual members or subgroups of members of the Markush group.

[0267] As will be understood by those skilled in the art, for any and all purposes, e.g., with respect to providing a written description, all ranges disclosed herein also encompass any and all possible subranges and combinations of subranges. Any recited range can be readily recognized as fully descriptive and allowing for division of the same range into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range described herein can be readily broken down into a lower third, middle third, and upper third, etc. Also, as will be understood by those skilled in the art, all language such as "up to," "at least," "greater than," "less than," "less than," etc., refers to a range that includes the recited numbers and can subsequently be broken down into subranges as described above. Finally, as will be understood by those skilled in the art, a range includes individual members. Thus, for example, a group having 1 to 3 items refers to a group having 1, 2, or 3 items. Similarly, a group having 1 to 5 items refers to a group having 1, 2, 3, 4, or 5 items, etc.

[0268] While various aspects and embodiments are disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

Claims

1. The method of increasing the permeability of the blood-brain barrier, comprising: providing a targeting peptide capable of binding to carbonic anhydrase IV, thereby increasing the permeability of the blood-brain barrier.

2. The method of claim 1 , wherein at least one activity of the carbonic anhydrase IV is decreased by binding to a targeting peptide.

3. The method of increasing the permeability of the blood-brain barrier, comprising: decreasing carbonic anhydrase IV activity, thereby increasing the permeability of the blood-brain barrier.

4. The method of any one of claims 1 to 3, wherein the targeting peptide binds to the zinc-binding site and / or the hydrophobic substrate-binding pocket of the carbonic anhydrase IV.

5. 5. The method of any one of claims 1 to 4, wherein the permeability of the blood-brain barrier is increased by at least 25%, 50%, 75%, 100% or more compared to the absence of target peptide or reduced carbonic anhydrase IV activity.

6. 1. A method for delivering a payload to the nervous system, the method comprising: providing a targeting peptide capable of binding to carbonic anhydrase IV or a derivative thereof, said targeting peptide being part of a delivery system, said delivery system comprising said payload to be delivered to the nervous system; administering the delivery system to the subject; A method comprising:

7. 6. The method of claim 5, wherein the delivery system comprises nanoparticles, nanotubes, nanowires, dendrimers, liposomes, ethosomes and aquasomes, polymersomes and niosomes, foams, hydrogels, cubosomes, quantum dots, exosomes, macrophages, and combinations thereof.

8. The method of claim 5 , wherein the delivery system comprises a viral or non-viral vector.

9. 9. The method of claim 8, wherein the viral vector comprises an adenoviral vector, an AAV vector, a lentiviral vector, or a retroviral vector, and optionally the target peptide is part of a capsid protein of an AAV vector.

10. 10. The method of claim 9, wherein the AAV vector is a vector selected from the group consisting of AAV1, AAV2, AAV3, AAV3b, AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, AAV10, AAV-DJ, human isolate hu.31, human isolate hu.32, rhesus monkey isolate rh.8, rhesus monkey isolate rh.10, and variants thereof.

11. 9. The method of claim 8, wherein the non-viral vector comprises lipid-based nanoparticles, polymeric nanoparticles, inorganic nanoparticles, surfactant-based emulsions, nanowires, silica nanoparticles, peptide or protein-based particles, lipid-polymer particles, nanolipoprotein particles, and combinations thereof.

12. 12. The method of any one of claims 5 to 11, wherein the payload delivered to the nervous system is a biological molecule, a non-biological molecule, or a combination thereof, optionally wherein the biological molecule is selected from the group consisting of a nucleic acid sequence, a protein, a peptide, a lipid, a polysaccharide, and a combination thereof.

13. The method of any one of claims 5 to 12, wherein the payload is a therapeutic molecule.

14. The nucleic acid sequence delivered to the nervous system comprises: a) trophic, growth, or other soluble factors that may be released from the transduced cell and affect the survival or function of that cell and / or surrounding cells; b) a cDNA that restores protein function to a human or animal carrying a genetic mutation in that gene; c) a cDNA encoding a protein that can be used to control or modify a cellular activity or state; d) a cDNA encoding a protein or nucleic acid used to assess the state of a cell; e) cDNA and / or associated guide RNA for genome engineering; f) Sequences for genome editing by homologous recombination; g) a DNA sequence encoding a therapeutic RNA; h) an shRNA or artificial miRNA delivery system; or The method of claim 12, comprising i) one or more DNA sequences that affect splicing of an endogenous gene.

15. 15. The method of any one of claims 1 to 14, wherein the carbonic anhydrase IV is mouse carbonic anhydrase IV, and optionally the carbonic anhydrase IV has an amino acid sequence having at least 80% sequence identity to the amino acid sequence of SEQ ID NO:

179.

16. 15. The method of any one of claims 1 to 14, wherein the carbonic anhydrase IV is human carbonic anhydrase IV, and optionally the carbonic anhydrase IV has an amino acid sequence having at least 80% sequence identity to the amino acid sequence of SEQ ID NO:

180.

17. The targeting peptide, when bound, is capable of targeting one or more positions that are functionally equivalent to (1) S20, G21, W22, L36, W41, P42, E90, V111, Q112, H114, H139, V141, K143, F156, L217, T218, T219, P220, N221, D223, or W228 in the carbonic anhydrase IV having the amino acid sequence of SEQ ID NO: 179, or (2) SEQ ID NO: The method according to any one of claims 1 to 16, wherein the method is capable of interacting with one or more positions functionally equivalent to S21, H22, W23, L37, W42, G43, M92, K113, Q114, H116, H141, V143, E145, Q158, L224, T225, T226, P227, T228, D231 or W236 in the carbonic anhydrase IV having an amino acid sequence of 180.

18. 18. The method of any one of claims 1-17, wherein the targeting peptide comprises: (1) an amino acid sequence selected from the group consisting of SEQ ID NOs: 70-174; or (2) an amino acid sequence having at least 80% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 70-174; optionally, the targeting peptide comprises an amino acid sequence selected from SEQ ID NOs: 70-108; and further optionally, the targeting peptide comprises an amino acid sequence selected from SEQ ID NOs: 70-86.

19. 19. The method of any one of claims 1 to 18, wherein the targeting peptide comprises: (1) an amino acid sequence selected from the group consisting of AKPTPLLGLLQAQTG (SEQ ID NO: 70), AKPTPLLLLLQAQTG (SEQ ID NO: 71), AQPPLGGLLAQAQTG (SEQ ID NO: 72), AKPPGPWAEAQAQTG (SEQ ID NO: 73), and AQPPLLGGLAQAQTG (SEQ ID NO: 74); or (2) an amino acid sequence having at least 80% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 70-74.

20. 20. The method of any one of claims 9 to 19, wherein the targeting peptide is inserted between two adjacent amino acids at AA587-594 of SEQ ID NO: 178 of the AAV9 vector, or a functional equivalent of AA587-594 in an amino acid sequence that is at least 80% identical to SEQ ID NO:

178.

21. 21. The method of any one of claims 9 to 20, wherein the targeting peptide is inserted between AA588-589 of SEQ ID NO: 178 of the AAV9 vector, or a functional equivalent of AA588-589 in an amino acid sequence at least 80% identical to SEQ ID NO:

178.

22. The method of any one of claims 9 to 21, wherein the AAV vector is conjugated to a nanoparticle, a second molecule, or a combination thereof.

23. The method of any one of claims 5 to 22, wherein said administration is systemic, and optionally said administration is intravenous or intrathecal.

24. The method of any one of claims 5 to 23, wherein the subject is a mammal, optionally wherein the subject is a human.

25. 25. The method of any one of claims 5 to 24, wherein the subject is suffering from or at risk of developing one or more of: chronic pain, Friedreich's ataxia, Huntington's disease (HD), Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), spinal muscular atrophy types I and II (SMA I and II), Friedreich's ataxia (FA), spinocerebellar ataxia, multiple sclerosis (MS), chronic traumatic encephalopathy (CTE), HIV-1 associated dementia, or a lysosomal storage disorder involving cells in the CNS, and optionally the lysosomal storage disorder involving cells in the CNS is Krabbe disease, Sandhoff disease, Tay-Sachs disease, Gaucher disease (types I, II or III), Niemann-Pick disease (NPC1 or NPC2 deficiency), Hurler syndrome, Pompe disease, or Batten disease.

26. 25. The method of any one of claims 5 to 24, wherein the subject is suffering from, is at risk of developing, or has suffered from stroke, traumatic brain injury, epilepsy, or spinal cord injury.

27. An adeno-associated virus (AAV) capsid protein containing a targeting peptide with binding specificity for carbonic anhydrase IV.

28. 28. The AAV capsid protein of claim 27, wherein the targeting peptide is a part of the capsid protein of the rAAV vector.

29. 29. The AAV capsid protein of claim 27 or 28, wherein the targeting peptide is inserted between two adjacent amino acids at AA587-594 of SEQ ID NO: 178, or a functional equivalent of AA587-594 in an amino acid sequence that is at least 80% identical to SEQ ID NO:

178.

30. The AAV capsid protein of any one of claims 27 to 29, wherein the targeting peptide comprises: (1) an amino acid sequence selected from the group consisting of SEQ ID NOs: 70-174; or (2) an amino acid sequence having at least 80% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 70-174.

31. The AAV capsid protein of any one of claims 27 to 30, wherein the AAV is a vector selected from the group consisting of AAV1, AAV2, AAV3, AAV3b, AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, AAV10, AAV-DJ, human isolate hu.31, human isolate hu.32, rhesus isolate rh.8, rhesus isolate rh.10, and variants thereof.

32. A recombinant adeno-associated virus (rAAV) comprising an AAV capsid protein according to any one of claims 27 to 31.

33. 1. A recombinant adeno-associated virus (rAAV) comprising an AAV capsid protein comprising a targeting peptide having binding specificity for carbonic anhydrase IV, wherein the amino acid sequence of the targeting peptide is inserted between two adjacent amino acids at AA 587-594 of the AAV capsid protein, or a functional equivalent thereof.

34. The rAAV of claim 33, wherein the two adjacent amino acids are AA588 and AA589.

35. The rAAV of claim 33 or 34, wherein the targeting peptide comprises: (1) an amino acid sequence selected from the group consisting of SEQ ID NOs: 70-174, or (2) an amino acid sequence having at least 80% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 70-174.

36. 32. A composition for use in delivering an agent to the nervous system of a subject in need thereof, the composition comprising an AAV comprising (1) an AAV capsid protein of any one of claims 27-31, and (2) an agent to be delivered to the nervous system of the subject, optionally wherein the nervous system is the central nervous system (CNS), the peripheral nervous system (PNS), or a combination thereof.

37. 37. The composition of claim 36, wherein the nervous system is a brain endothelial cell, a neuron, a capillary in the brain, an arteriole in the brain, an artery in the brain, or a combination thereof.

38. The composition of any one of claims 36 to 37, wherein the composition is a pharmaceutical composition comprising one or more pharma- ceutically acceptable carriers.

39. The composition for use according to any one of claims 36 to 38, wherein the agent to be delivered comprises a nucleic acid, a peptide, a small molecule, an aptamer, or a combination thereof.

40. An antibody or fragment thereof, comprising an amino acid sequence that has binding specificity for carbonic anhydrase IV.

41. The antibody or fragment thereof according to claim 40, comprising (1) an amino acid sequence selected from the group consisting of SEQ ID NOs: 70 to 174, or (2) an amino acid sequence having at least 80% sequence identity with an amino acid sequence selected from the group consisting of SEQ ID NOs: 70 to 174.

42. The antibody or fragment thereof of claim 40 or 41, wherein the antibody or fragment thereof is a bispecific antibody comprising at least one Fab having specificity for carbonic anhydrase IV.

43. An antibody conjugate comprising the antibody or fragment thereof according to any one of claims 40 to 42, further comprising a therapeutic agent or a detectable label.

44. A peptide or a derivative or conjugate thereof having specificity for carbonic anhydrase IV.

45. A nucleic acid comprising a sequence encoding an antibody or a fragment thereof according to any one of claims 40 to 43, or a peptide or a derivative or conjugate thereof according to claim 44.

46. A delivery system comprising: (1) a targeting peptide having specificity for carbonic anhydrase IV; and (2) an agent.

47. 47. The delivery system of claim 46, wherein the targeting peptide is (1) displayed on the surface of the delivery system or (2) partially embedded in the delivery system.

48. 48. The delivery system of claim 46 or 47, wherein the delivery system is selected from the group consisting of nanoparticles, nanotubes, nanowires, dendrimers, liposomes, ethosomes and aquasomes, polymersomes and niosomes, foams, hydrogels, cubosomes, quantum dots, exosomes, macrophages, and combinations thereof.

49. The delivery system according to any one of claims 46 to 48, wherein the delivery system comprises a viral vector or a non-viral vector.

50. 50. The delivery system of any one of claims 46 to 49, wherein the delivery system comprises nanoparticles selected from the group consisting of lipid-based nanoparticles, polymeric nanoparticles, inorganic nanoparticles, surfactant-based emulsions, nanowires, silica nanoparticles, virus-like particles, peptide or protein-based particles, lipid-polymer particles, nanolipoprotein particles, and combinations thereof.

51. 1. A method for designing a targeting peptide having specificity for carbonic anhydrase IV, comprising: (1) one or more positions functionally equivalent to S20, G21, W22, L36, W41, P42, E90, V111, Q112, H114, H139, V141, K143, F156, L217, T218, T219, P220, N221, D223 or W228 in the carbonic anhydrase IV having the amino acid sequence of SEQ ID NO: 179, or (2) an amino acid of SEQ ID NO: 180 22. A method comprising generating in silico one or more targeting peptides capable of interacting with one or more positions functionally equivalent to S21, H22, W23, L37, W42, G43, M92, K113, Q114, H116, H141, V143, E145, Q158, L224, T225, T226, P227, T228, D231 or W236 in said carbonic anhydrase IV having the sequence:

52. generating said one or more targeting peptides in silico; generating a plurality of candidate peptides in silico; performing a computer-assisted docking simulation for each of the plurality of candidate peptides that bind to the carbonic anhydrase IV; (1) one or more positions functionally equivalent to S20, G21, W22, L36, W41, P42, E90, V111, Q112, H114, H139, V141, K143, F156, L217, T218, T219, P220, N221, D223 or W228 in the carbonic anhydrase IV having the amino acid sequence of SEQ ID NO: 179, or (2) S21, H22, W23 in the carbonic anhydrase IV having the amino acid sequence of SEQ ID NO: 180, and analyzing the structure of the carbonic anhydrase IV bound to one or more of the plurality of candidate peptides to identify one or more targeting peptides capable of interacting with one or more positions functionally equivalent to L37, W42, G43, M92, K113, Q114, H116, H141, V143, E145, Q158, L224, T225, T226, P227, T228, D231, or W236.

53. obtaining a binding score for each of the plurality of candidate peptides that bind to carbonic anhydrase IV; and selecting one or more of the plurality of candidate peptides having a binding score above a threshold as a targeting peptide having specificity for carbonic anhydrase IV.

54. 54. The method of claim 53, comprising comparing the binding scores of two or more of the plurality of candidate peptides to rank the candidate peptide sequences.

55. 55. The method of claim 53 or 54, wherein obtaining the binding score for each of the plurality of candidate peptide sequences comprises: (1) counting the total number of atoms at the interface between the candidate peptide and the carbonic anhydrase IV; (2) counting the total number of atoms in the candidate peptide, where the atoms are in conflict with the carbonic anhydrase IV; (3) obtaining a bond angle of the candidate peptide; and (4) obtaining a binding depth of the candidate peptide.

56. A method of increasing the permeability of the blood-brain barrier in a mouse species, comprising providing a targeting peptide capable of binding to Ly6c1, thereby increasing the permeability of the blood-brain barrier in said mouse species.

57. 57. The method of claim 56, wherein the targeting peptide has an amino acid sequence selected from the group consisting of: 1) AQRYQGDSVAQ (SEQ ID NO: 7), AQWSTNAGYAQ (SEQ ID NO: 8), AQERVGFAQAQ (SEQ ID NO: 9), AQWMTHGSAAQ (SEQ ID NO: 10), and SPRYKGDSVAQ (SEQ ID NO: 57); or (2) an amino acid sequence having at least 80% sequence identity to an amino acid sequence selected from the group consisting of AQRYQGDSVAQ (SEQ ID NO: 7), AQWSTNAGYAQ (SEQ ID NO: 8), AQERVGFAQAQ (SEQ ID NO: 9), AQWMTHGSAAQ (SEQ ID NO: 10), and SPRYKGDSVAQ (SEQ ID NO: 57).

58. 57. The method of claim 56, wherein the targeting peptide has an amino acid sequence of SPRYKGDSVAQ (SEQ ID NO:57), or an amino acid sequence having at least 80% identity to SEQ ID NO:

57.

59. 59. The method of claim 57 or 58, wherein the targeting peptide is inserted between two adjacent amino acids at AA587-590 of SEQ ID NO: 178, or a functional equivalent of AA587-590 in an amino acid sequence at least 80% identical to SEQ ID NO: 178.

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