Astrocytic phosphoprotein (pea-15) for use in the treatment and / or prevention of a neuronal disorder

Abstract

The present invention provides methods and compositions comprising a C-terminal fragment of the Astrocytic phosphoprotein (PEA-15) protein in the treatment and / or prevention of a disorder or a disease Preferably, the disorder or a disease is a neurodevelopmental, a neurological or a psychiatric disorder or disease.

Description

[0001] Use of Astrocytic phosphoprotein (PEA- 15) in the treatment and / or prevention of a disorder or disease

[0002] FIELD OF THE INVENTION

[0003] The present invention provides methods and compositions comprising the Astrocytic phosphoprotein (PEA-15) protein in the treatment and / or prevention of a disorder or a disease. Preferably, the disorder or a disease is a neurodevelopmental, a neurological or a psychiatric disorder or disease.

[0004] BACKGROUND OF THE INVENTION

[0005] In the mammalian brain, adult neurogenesis occurs in two distinct regions: the sub ventricular zone (SVZ), where neurons migrate into the olfactory bulb, and in the dentate gyrus (DG) of the hippocampus (Altman, J. "Are new neurons formed in the brains of adult mammals?" Science 135, 1127-1128 (1962).). In the DG, aNSC reside in the subgranular zone (SGZ) and, upon exiting quiescence, produce transit-amplifying progenitors, with high proliferative properties. Progenitors then give rise to neuroblasts, which migrate through the granular cell layer and mature into newborn granule neurons that functionally integrate into the hippocampal network. Increasing evidence indicates that adult hippocampal neurogenesis plays a role in stress resilience. Indeed, blocking adult neurogenesis reduces stress resilience, whereas increasing adult neurogenesis reduces depression-like symptoms after chronic stress.

[0006] In the DG, a specialized microenvironment called the neurogenic niche regulates every step of adult neurogenesis, from cell proliferation to the synaptic integration of new neurons. The neurogenic niche includes astrocytes, microglia, endothelial cells, oligodendrocytes, aNSC, progenitors, mature and immature neurons. Astrocytes in particular, release important molecules that promote adult neurogenesis, including ATP, glutamate and D-serine.

[0007] An agent modulating the vesicular release from astrocytes for use in the treatment and / or prevention of a neurodevelopmental, a neurological or a psychiatric disorder or disease is thus needed. SUMMARY OF THE INVENTION

[0008] The present invention provides an agent modulating (e.g. enhancing) the vesicular release from astrocytes for use in the treatment and / or prevention of a neurodevelopmental, a neurological or a psychiatric disorder or disease

[0009] The present invention also provides a pharmaceutical composition comprising a therapeutically effective amount of the sequence of the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 1, a fragment, a derivative or a variant thereof, and a pharmaceutically acceptable carrier and / or diluent.

[0010] The present invention also provides a pharmaceutical composition comprising a therapeutically effective amount of a C-terminal fragment of the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, and a pharmaceutically acceptable carrier and / or diluent for use in the treatment and / or prevention of a disorder or disease related to the hippocampus selected from the group comprising a neurodevelopmental, a neurological or a psychiatric disorder or disease.

[0011] The present invention also provides a C-terminal fragment of the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof.

[0012] The present invention further contemplates a nucleic acid encoding the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 1, a fragment, a derivative or a variant thereof.

[0013] The present invention also provides a nucleic acid encoding the C-terminal fragment of the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, of the invention, or a C-terminal fragment of the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, conjugated to a moiety capable of absorptive-mediated or receptor-mediated transcytosis through a subject's blood brain barrier of the invention.

[0014] The present invention also provides a vector comprising the nucleic acid of the invention.

[0015] The present invention also provides a composition comprising (a) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, of the invention,

[0016] (b) a nucleic acid of the invention, or

[0017] (c) a vector of the invention.

[0018] The present invention also provides a pharmaceutical composition comprising

[0019] (a) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, of the invention,

[0020] (b) a nucleic acid of the invention, or

[0021] (c) a vector of the invention, and a pharmaceutically acceptable carrier and / or diluent.

[0022] The present invention also provides a kit comprising

[0023] (a) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, of the invention,

[0024] (b) a nucleic acid of the invention,

[0025] (c) a vector of the invention,

[0026] (d) a pharmaceutical composition of the invention, or

[0027] (e) a composition of the invention, and optionally instructions for use.

[0028] The present invention also provides a method of treatment and / or prevention of a neurodevelopmental, a neurological or a psychiatric disorder or disease related to the hippocampus, comprising administering

[0029] (a) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or conservative variant thereof, of the invention, or

[0030] (b) a nucleic acid of the invention,

[0031] (c) a vector of the invention, or

[0032] (d) a pharmaceutical composition of the invention. The present invention also provides methods of treatment and / or prevention of a disease or disorder comprising (a) providing an agent of the invention and (b) administering said agent to a subject in need thereof.

[0033] DESCRIPTION OF THE FIGURE

[0034] Figure 1 - (A) Number of adult Hippocampal stem / progenitor cells that incorporated BrdU in the Hippocampus of mice after treatment with vehicle (Tyrode) or PEA116 (F = 27.72, p < 0.001, One-Way ANOVA followed by Tukey’s multiple comparisons test, n = 8 mice per group). (B) Mice were stresses using a chronic restraint stress for 21 days, that induces depressive-like symptoms and increased anxiety. The histogram shows the anxiety score calculated from the combination of the behavior on 3 different tests on control mice (NaCl + Tyrode), PEA116-treated mice and PEA116+TMZ (Temozolomide)-treated mice, to inhibit adult neurogenesis. (Elevated-Plus Maze EPM, Light-Dark test LDT and Marble Burying Test MB tests, F = 3.038, p = 0.0704, One-Way ANOVA followed by Tukey’s multiple comparisons test, NaCl+Tyrode: n = 8 mice, NaCl+PEA116: n = 7 mice, TMZ+PEA116: n = 8 mice; NaCl+Tyrode, NaCl+PEAl 16, TMZ+PEA116 vs 0.5: t = 0.6547, p = 0.5336, t = 4.239, p = 0.0054, t = 0.07778, p = 0.9402, One-sample t-test). (C) Number of newborn hippocampal neurons (labelled CldU+NeuN+) in the 3 groups mentioned on Figure 1C. Number of CldU+ cells (F = 21.29, p < 0.001 , One-Way ANOVA followed by Tukey’s multiple comparisons test, n = 8 mice per group) (F = 15.56, p = 0.0004, non-parametric Kruskal-Wallis test followed by Dunn’s multiple comparisons test, n = 8 mice per group).

[0035] DESCRIPTION OF THE INVENTION

[0036] Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. The publications and applications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention. In addition, the materials, methods, and examples are illustrative only and are not intended to be limiting.

[0037] In the case of conflict, the present specification, including definitions, will control. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of skill in art to which the subject matter herein belongs. As used herein, the following definitions are supplied in order to facilitate the understanding of the present invention.

[0038] The term "comprise / comprising" is generally used in the sense of "include / including", that is to say permitting the presence of one or more features or components. This term also encompasses the more restricted term "consist / consisting".

[0039] As used in the specification and claims, the singular form "a", "an" and "the" include plural references unless the context clearly dictates otherwise.

[0040] The term "amino acid" includes all of the naturally occurring amino acids as well as modified amino acids.

[0041] As used herein, "at least one" means "one or more", "two or more", "three or more", etc.

[0042] The term “about,” particularly in reference to a given quantity, is meant to encompass deviations of plus or minus ten (10) percent (%).

[0043] While conducting investigations on the role of molecules released by astrocytes in the regulation of cell proliferation in the dentate gyrus (DG) and their impact on hippocampal function, the Inventors found that medium conditioned by astrocytes increased cell proliferation in the DG, an effect that was dependent on vesicular release. Analysis of the astrocyte-conditioned medium revealed that the neurogenic effect is due to the presence of Astrocytic phosphoprotein (PEA-15) protein and in particular of peptidic fragments thereof.

[0044] The present invention thus contemplates an agent modulating (e.g. enhancing) the vesicular release from astrocytes for use in the treatment and / or prevention of a neurodevelopmental, a neurological or a psychiatric disorder or disease. According to one aspect, the agent of the invention increases ERK2 phosphorylation and decreases the expression of genes involved in adult neural stem cell (aNSC) quiescence, thus resulting in an increased astrocyte vesicular release.

[0045] The agent of the invention can be selected from the group comprising a nucleic acid, a chemical compound, a peptide or analog thereof, an antibody or an antigen-binding fragment thereof, and an antibody mimetic, or a combination of one or more thereof.

[0046] In one aspect, the agent of the invention is a peptide or a protein.

[0047] The terms "polypeptide," "peptide" and "protein" are used interchangeably to refer to a polymer of amino acid residues. The term also applies to amino acid polymers (e.g. analogs) in which one or more amino acids are chemical analogues or modified derivatives of corresponding naturally occurring amino acids. The terms "polypeptide of the invention", "peptide of the invention", and "protein of the invention", refer all to an amino acid sequence described herein (and referred to as SEQ ID No, X, Y or Z for example). The "polypeptide of the invention", "peptide of the invention", and "protein of the invention" can be either natural or synthetic.

[0048] Preferably, the protein of the invention is the Astrocytic phosphoprotein (PEA-15) protein which amino acid sequence is as set forth in SEQ ID NO. 1. The skilled artisan will readily appreciate that the invention is not limited to the sequence(s) depicted herein, but also includes fragments, variants or derivatives thereof.

[0049] As used herein, a “fragment” of one or more polypeptide sequence of the invention refers to a sequence containing less amino acids in length than the respective sequences of the invention while retaining the biological activity described herein. Preferably, this biologically active fragment contains, at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of the entire length of the reference polypeptide sequence. Preferably also, this biologically active fragment contains, about 10 to about 20 amino acids, about 20 to about 40 amino acids, about 40 to about 60 amino acids, about 60 to about 80 amino acids, about 80 to about 100 amino acids, and about 100 to about 129 amino acids, of the sequence of reference, i.e. SEQ ID NO. 1.

[0050] In one aspect, the PEA-15 biologically active fragment comprises a C -terminal fragment (also named PEA116) of PEA-15, or a variant thereof. Preferably, this fragment contains, about 10 to about 20 amino acids, about 20 to about 40 amino acids, about 40 to about 60 amino acids, about 60 to about 80 amino acids, about 80 to about 100 amino acids, and about 100 to about 129 amino acids, of the C -terminal fragment of the sequence of reference, i.e. SEQ ID NO. 1. More preferably, the C-terminal fragment of PEA-15 (also named PEA116) contains 12 amino acids of the C-terminal fragment of the sequence of reference, i.e. SEQ ID NO. 1.

[0051] In one aspect, the sequence of the C-terminal fragment of PEA- 15 comprises the stretch of amino acids KLAPPP, or a biologically active fragment or variant thereof.

[0052] In one aspect, the sequence of the C-terminal fragment of PEA- 15 is as set forth in SEQ ID NO. 2, a biologically active fragment or a variant thereof.

[0053] As used herein, the term “C-terminal fragment” refers to a portion of a full-length polypeptide comprising a contiguous amino acid sequence located toward the carboxy -terminal (C-terminal) region of the polypeptide, but which does not necessarily include the ultimate C-terminal residue. The C-terminal fragment of the invention includes residues that are positioned downstream (i.e., closer to the C-terminus) relative to the full-length sequence and may encompass functional domains or structural motifs associated with the C-terminal region. Such C-terminal fragments of the invention may retain partial or full biological activity or even exhibit higher biological activity compared to the parent polypeptide and may be naturally occurring, recombinantly produced, synthetic, or modified, and may be used in isolation or as part of a fusion protein, conjugate, or pharmaceutical composition. As used herein, the term “N- terminal fragment” refers to a portion of a full-length polypeptide comprising a contiguous amino acid sequence located toward the amino-terminal (N-terminal) region of the polypeptide, but which does not necessarily include the initial N-terminal residue. The N-terminal fragment of the invention includes residues that are positioned upstream (i.e., closer to the N-terminus) relative to the full-length sequence, and may encompass structural motifs, signal sequences, or functional domains associated with the N-terminal region. Such N-terminal fragments of the invention may retain partial or full biological activity of the parent polypeptide and may be naturally occurring, recombinantly produced, synthetic, or modified, and may be used in isolation or as part of a fusion protein, conjugate, or pharmaceutical composition.

[0054] As used herein, the term “variant” refers to biologically active variants or derivatives of one or more polypeptide sequence of the invention. In general, the term “variant” refers to molecules having a native sequence and structure with one or more additions, substitutions (generally conservative in nature) and / or deletions (e.g. splice variants), relative to the native molecule, so long as the modifications do not destroy biological activity, and which are “substantially homologous” to the reference molecule. In general, the sequences of such variants are functionally, i.e. biologically active variants and will have a high degree of sequence homology to the reference sequence, e.g., sequence homology of more than 50%, generally more than 70%, even more particularly more than 80%, such as at least 90% or 95% or more, when the two sequences are aligned.

[0055] As used herein, the term “conservative variant” refers to an amino acid sequence that differs from a reference peptide by one or more substitutions, insertions, or deletions of amino acids, wherein the substitutions are conservative in nature. A “conservative substitution” is understood as the replacement of one (or more) amino acid residue(s) with one (or more) different amino acid residue(s) that has / have similar physicochemical properties (such as charge, hydrophobicity, polarity, or size), such that the overall structure, activity, and / or therapeutic function of the peptide is substantially retained. Examples of conservative substitutions include, but are not limited to, substitution of leucine for isoleucine, valine for alanine, glutamic acid for aspartic acid, glutamine for asparagine, and lysine for arginine. Conservative variants as defined herein may exhibit comparable or enhanced biological activity, stability, or bioavailability relative to the reference peptide, and are considered to fall within the scope of the invention.

[0056] Conservative amino acid substitutions are herein defined as exchanges within one of the following five groups:

[0057] I. Small aliphatic, nonpolar or slightly polar residues: Ala, Ser, Thr, Pro, Gly

[0058] II. Polar, positively charged residues: His, Arg, Lys

[0059] III. Polar, negatively charged residues: and their amides: Asp, Asn, Glu, Gin

[0060] IV. Large, aromatic residues: Phe, Tyr, Trp

[0061] V. Large, aliphatic, nonpolar residues: Met, Leu, Phe, Vai, Cys,

[0062] VI. Hydrophobic amino acids with aliphatic or aromatic side chains: Ala, Vai, He, Pro, Leu, Phe.

[0063] In one aspect, the variant of the invention comprises, or consists of, one or more additions, substitutions (such as e.g. one or more mutations) and / or deletions within the sequence of reference, i.e. SEQ ID NO. 1, SEQ ID NO. 2 or a fragment of any one of these sequences.

[0064] One or more mutations comprise at least one mutation, at least two mutations, at least three mutations, at least four mutations, at least five mutations, at least six mutations, at least seven mutations, at least eight mutations, at least nine mutations, at least ten mutations or more within the sequence of reference, i.e. SEQ ID NO. 1, SEQ ID NO. 2 or a fragment of any one of these sequences.

[0065] For example, one or more mutations within the sequence of SEQ ID NO. 2 comprises, one mutation at position 1, one mutation at position 2, one mutation at position 3, one mutation at position 4, one mutation at position 5, one mutation at position 6, one mutation at position 7, one mutation at 8, one mutation at position 9, one mutation at position 10, one mutation at position 11, and one mutation at position 12, or a combination of two or more mutations at any one of the positions.

[0066] In one aspect, the variant of a sequence of SEQ ID NO. 2 comprises (R / K)2-3-XI-S-O-X-C> (SEQ ID NO. 3), where X is any amino acid, and is a hydrophobic amino acid.

[0067] Since an inherent problem with native peptides (in L-form) is degradation by natural proteases, the peptide of the invention may be prepared to include D-forms and / or "retro-inverso isomers" of the peptide.

[0068] As used herein, "retro-inverso isomer" refers an isomer of a linear peptide in which the direction of the sequence is reversed and the chirality of each amino acid residue is inverted; thus, there can be no end-group complementarity.

[0069] In this case, retro-inverso isomers of fragments of the peptide of the invention are prepared. Protecting the peptide from natural proteolysis increases the effectiveness of the specific heterobivalent or heteromultivalent compound. A higher biological activity is predicted for the retro-inverso containing peptide when compared to the non-retro-inverso containing analog owing to protection from degradation by native proteinases. Furthermore, they have been shown to exhibit an increased stability and lower immunogenicity (Sela M. and Zisman E., "Different roles of D-amino acids in immune phenomena" FASEB J. 11, 449, 1997).

[0070] Retro-inverso peptides are prepared for peptides of known sequence as described for example in Sela and Zisman, (1997). The present invention further contemplates a nucleic acid encoding the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 1, a fragment, a derivative or a variant thereof.

[0071] The terms "nucleic acid", "polynucleotide," and "oligonucleotide" are used interchangeably and refer to any kind of deoxyribonucleotide (e.g. DNA, cDNA, ...) or ribonucleotide (e.g. RNA, mRNA, ...) polymer or a combination of deoxyribonucleotide and ribonucleotide (e.g. DNA / RNA) polymer, in linear or circular conformation, and in either single - or double - stranded form. These terms are not to be construed as limiting with respect to the length of a polymer and can encompass known analogues of natural nucleotides, as well as nucleotides that are modified in the base, sugar and / or phosphate moieties (e.g. phosphorothioate backbones). In general, an analogue of a particular nucleotide has the same base-pairing specificity, i.e., an analogue of A will base-pair with T.

[0072] As used herein, a “fragment” of one or more nucleic acid sequence of the invention refers to a sequence containing less nucleic acids in length than the respective sequences of the invention while retaining the biological activity described herein. Preferably, this fragment contains, at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of the entire length of the reference polynucleotide sequence encoding a protein of the invention.

[0073] As used herein, the term “variant” refers to biologically active derivatives of one or more nucleic acid sequence of the invention. In general, the term “variant” refers to molecules having a native sequence and structure with one or more additions, substitutions (generally conservative in nature) and / or deletions (e.g. splice variants), relative to the native molecule, so long as the modifications do not destroy biological activity, and which are “substantially homologous” to the reference molecule. In general, the sequences of such variants are functionally, i.e. biologically, active variants and will have a high degree of sequence homology to the reference sequence, e.g., sequence homology of more than 50%, generally more than 70%, even more particularly more than 80%, such as at least 90% or 95% or more, when the two sequences are aligned.

[0074] In one aspect, the variant is a conservative variant of the Astrocytic phosphoprotein (PEA-15) as set forth in SEQ ID NO:2, sharing at least 50%, 70%, 80%, 90%, or 95% sequence homology, such as 95%, 96%, 97%, 98%, or 99%, with SEQ ID NO. 2. The present invention further contemplates compositions and pharmaceutical compositions.

[0075] In one aspect, a pharmaceutical composition of the invention comprises a therapeutically effective amount of the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 1, a fragment, a derivative or a variant thereof, and a pharmaceutically acceptable carrier and / or diluent.

[0076] The invention provides a pharmaceutical composition comprising a therapeutically effective amount of a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, and a pharmaceutically acceptable carrier and / or diluent for use in the treatment and / or prevention of a disorder or disease related to the hippocampus selected from the group comprising a neurodevelopmental, a neurological or a psychiatric disorder or disease.

[0077] In one aspect, the invention provides a pharmaceutical composition comprising a therapeutically effective amount of a C-terminal fragment of the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4 or a conservative variant thereof, and a pharmaceutically acceptable carrier and / or diluent for use in the treatment and / or prevention of a disorder or disease related to the hippocampus selected from the group comprising a neurodevelopmental, a neurological or a psychiatric disorder or disease.

[0078] The term "therapeutically effective amount" as used herein means an amount of an agent of the invention high enough to significantly positively modify the symptoms and / or condition to be treated, but low enough to avoid serious side effects (at a reasonable risk / benefit ratio), within the scope of sound medical judgment. The therapeutically effective amount of the agent of the invention is selected in accordance with a variety of factors including type, species, age, weight, sex and medical condition of the patient; the severity of the condition to be treated; the route of administration; the renal and hepatic function of the patient. A physician of ordinary skill in the art can readily determine and prescribe the effective amount of the agent required to prevent, counter or arrest the progress of the disease or disorder to be treated.

[0079] As used herein, the term “pharmaceutical composition” refers to a formulation comprising (i) at least one therapeutically active peptide fragment as defined herein, or (ii) a nucleic acid molecule encoding said peptide fragment, or (iii) a vector comprising such a nucleic acid molecule, in combination with one or more pharmaceutically acceptable carriers, excipients, stabilizers, solubilizers, delivery agents, or other auxiliary substances. The pharmaceutical composition of the invention can be specifically adapted for delivery across the blood-brain barrier (BBB) and is suitable for administration to a subject via a route that enables effective central nervous system (CNS) delivery, including but not limited to intravenous, intranasal, intrathecal, or intracerebro ventricular administration. In embodiments comprising a nucleic acid or vector, the composition may further comprise elements facilitating expression of the peptide fragment in target cells, such as promoters, regulatory sequences, and targeting ligands. The pharmaceutical composition of the invention may incorporate delivery-enhancing technologies, including receptor-mediated transport systems, cell-penetrating peptides, viral or non-viral vectors, lipid nanoparticles, exosomes, liposomes, or chemical modifications (e.g., PEGylation or lipidation), which facilitate transport across the BBB and / or targeted delivery to neural tissues. The pharmaceutical composition of the invention is formulated to deliver the active agent — peptide, nucleic acid, or vector — in a therapeutically effective amount for the prevention, treatment, or amelioration of diseases or disorders affecting the central nervous system.

[0080] “Pharmaceutically acceptable carrier or diluent” means a carrier or diluent that is useful in preparing a pharmaceutical composition that is generally safe, non-toxic, and desirable, and includes carriers or diluents that are acceptable for human pharmaceutical use.

[0081] Such pharmaceutically acceptable carriers can be sterile liquids, such as water and oils, including those of petroleum, animal, vegetable or synthetic origin, such as peanut oil, soybean oil, mineral oil, sesame oil and the like. Water is a preferred carrier when the pharmaceutical composition is administered intravenously. Saline solutions and aqueous dextrose and glycerol solutions can also be employed as liquid carriers, particularly for injectable solutions.

[0082] Pharmaceutically acceptable excipients include starch, glucose, lactose, sucrose, sodium stearate, glycerol monostearate, talc, sodium chloride, dried skim milk, glycerol, propylene glycol, water, ethanol and the like.

[0083] The pharmaceutical compositions may further contain one or more pharmaceutically acceptable salts such as, for example, a mineral acid salt such as a hydrochloride, a hydrobromide, a phosphate, a sulfate, etc.; and the salts of organic acids such as acetates, propionates, malonates, benzoates, etc. Additionally, auxiliary substances, such as wetting or emulsifying agents, pH buffering substances, gels or gelling materials, flavorings, colorants, microspheres, polymers, suspension agents, etc. may also be present herein. In addition, one or more other conventional pharmaceutical ingredients, such as preservatives, humectants, suspending agents, surfactants, antioxidants, anticaking agents, fillers, chelating agents, coating agents, chemical stabilizers, etc. may also be present, especially if the dosage form is a reconstitutable form. Suitable exemplary ingredients include macrocrystalline cellulose, carboxymethyf cellulose sodium, polysorbate 80, phenyletbyl alcohol, chiorobutanol, potassium sorbate, sorbic acid, sulfur dioxide, propyl gallate, the parabens, ethyl vanillin, glycerin, phenol, parachlorophenol, gelatin, albumin and a combination thereof. A thorough discussion of pharmaceutically acceptable excipients is available in REMINGTON'S PHARMACEUTICAL SCIENCES (Mack Pub. Co., N.J. 1991) which is incorporated by reference herein.

[0084] In one aspect, the invention provides a pharmaceutical composition, wherein the conservative variant, comprises, or consists of, one or more additions, substitutions and / or deletions within amino acid sequence SEQ ID NO. 2.

[0085] In one aspect, the invention provides a pharmaceutical composition, wherein the conservative variant comprises, or consists of, one or more additions, substitutions (such as e.g. one or more mutations) and / or deletions within the sequence of reference, i.e. SEQ ID NO. 1, SEQ ID NO. 2 or a fragment of any one of these sequences.

[0086] In one aspect, the invention provides a pharmaceutical composition, wherein the conservative variant, comprises, or consists of, one or more additions, substitutions and / or deletions within amino acid sequence SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4.

[0087] In one aspect, the invention provides a pharmaceutical composition, wherein the conservative variant, comprises, or consists of, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 or 23 additions, substitutions and / or deletions within amino acid sequence SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4.

[0088] In one aspect, the invention provides a pharmaceutical composition, wherein the conservative variant of SEQ ID NO. 2 comprises, or consists of, one or two mutations within SEQ ID NO. 2.

[0089] In one aspect, the invention provides a pharmaceutical composition, wherein the conservative variant comprises, or consists of, one or two additions, substitutions (such as e.g. one or more mutations) and / or deletions within the sequence of reference, i.e. SEQ ID NO. 1, SEQ ID NO. 2 or a fragment of any one of these sequences.

[0090] In one aspect, the invention provides a pharmaceutical composition, wherein the conservative variant of SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4 comprises, or consists of, one or two mutations within SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4.

[0091] In one aspect, the invention provides a pharmaceutical composition, wherein the conservative variant of SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4 comprises, or consists of, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 or 23 mutations within SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4.

[0092] In one aspect, the pharmaceutical composition of the invention is in a form for delivery across the blood brain barrier or is administered by direct injection into the central nervous system.

[0093] In one aspect, the pharmaceutical composition of the invention is in a form for delivery across the blood brain barrier or for administration by direct injection into the central nervous system.

[0094] As used herein, the term “delivery across the blood-brain barrier” refers to the transport, translocation, or uptake of a substance — such as a peptide, protein, nucleic acid, small molecule, or pharmaceutical composition of the invention — across the endothelial cell layer of cerebral microvessels that constitutes the blood-brain barrier (BBB), such that the substance reaches the brain parenchyma in a biologically active form. Delivery across the BBB may occur via passive diffusion, carrier-mediated transport, receptor-mediated transcytosis, adsorptive-mediated transcytosis, or through the use of delivery -enhancing systems such as cell-penetrating peptides, nanoparticles, lipid-based carriers, viral vectors, or chemical modifications that facilitate BBB penetration. The term “delivery across the blood-brain barrier” encompasses both direct and indirect strategies, including systemic administration of agents capable of crossing the BBB, and delivery of vectors or nucleic acids encoding the therapeutic molecules of the invention that are subsequently expressed within the CNS.

[0095] In one aspect, the pharmaceutical composition of the invention comprises peptides that may be modified to facilitate delivery across the blood-brain barrier (BBB) using a variety of strategies. Such modifications may include, but are not limited to: (i) lipidation, wherein lipid moieties (e.g., palmitic acid) are covalently attached to increase lipophilicity and passive diffusion; (ii) PEGylation, involving the conjugation of polyethylene glycol to enhance systemic stability and circulation time; (iii) cyclisation, to improve proteolytic resistance and membrane permeability; (iv) incorporation of D-amino acids to increase metabolic stability; (v) conjugation to targeting ligands such as transferrin, Angiopep-2, or antibodies against BBB receptors to enable receptor-mediated transcytosis; (vi) fusion to cell -penetrating peptides (CPPs), such as TAT or penetratin, to promote adsorptive-mediated transcytosis; (vii) encapsulation or association with nanocarriers including lipid nanoparticles, polymeric nanoparticles, or exosomes, optionally surface-functionalized with targeting ligands; and (viii) use of gene therapy vectors, such as adeno-associated viruses (e.g., AAV9, AAV-PHP.B), or lipid-based systems to deliver nucleic acids encoding the therapeutic peptide for in situ expression within the central nervous system. The pharmaceutical composition of the invention in a form for delivery across the blood brain barrier provides a non-invasive means of transporting therapeutic agents across cellular membranes and, in certain embodiments, across the blood-brain barrier. The pharmaceutical composition of the invention can be administered with repeated dosing regimens, rendering it particularly advantageous for chronic or long-term therapeutic applications. In specific implementations, the pharmaceutical composition of the invention exhibits inherent capability to traverse the blood-brain barrier, facilitating targeted delivery to central nervous system tissues without the need for invasive intervention.

[0096] As used herein, the term “direct injection into the central nervous system” refers to the administration of a substance, composition, or vector by means of a physical injection or targeted delivery that bypasses the blood-brain barrier and introduces the agent directly into the central nervous system (CNS) compartment. Such routes of administration include, but are not limited to, intracerebroventricular (ICV) injection, wherein the agent is delivered into the cerebral ventricles; intrathecal injection, involving administration into the cerebrospinal fluid (CSF) within the subarachnoid space (e.g., via lumbar puncture); intraparenchymal injection, wherein the substance is inj ected directly into brain tissue; and intracistemal injection, targeting the cistema magna. The term “direct injection into the central nervous system” further encompasses intranasal administration, wherein the agent is delivered via the nasal cavity and reaches the CNS through olfactory or trigeminal nerve pathways, thereby bypassing the systemic circulation and the blood-brain barrier. These administration methods are particularly suited for therapeutic agents with limited BBB permeability and enable localized or widespread CNS distribution. The pharmaceutical composition of the invention for administration by direct injection into the central nervous system permits precise spatial targeting within the CNS and facilitates the attainment of therapeutically effective concentrations at the site of interest. Direct injection into the central nervous system is particularly suited for conditions requiring immediate or region-specific pharmacological action and is applicable to a range of therapeutic modalities, including macromolecules, gene therapies, and viral vectors.

[0097] In another aspect, the correct delivery of the pharmaceutical composition is obtained by i) chemically modifying the SEQ ID NO. 1, fragment, derivative or variant thereof; ii) conjugating the SEQ ID NO. 1, fragment, derivative or variant thereof to a polypeptide capable of absorptive-mediated or receptor-mediated transcytosis through the subject's blood brain barrier, and / or iii) co-administering the SEQ ID NO. 1, fragment, derivative or variant thereof with an anti-glucocorticoid drug in a sufficient amount to increase permeability of the subject's blood brain barrier.

[0098] In another aspect, the correct delivery of the pharmaceutical composition is obtained by i) chemically modifying the SEQ ID NO. 2, fragment, derivative or variant thereof; ii) conjugating the SEQ ID NO. 2, fragment, derivative or variant thereof to a polypeptide capable of absorptive-mediated or receptor-mediated transcytosis through the subject's blood brain barrier, and / or iii) co-administering the SEQ ID NO. 2, fragment, derivative or variant thereof with an anti-glucocorticoid drug in a sufficient amount to increase permeability of the subject's blood brain barrier.

[0099] In another aspect, the correct delivery of the pharmaceutical composition is obtained by i) chemically modifying the SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4 fragment, derivative or variant thereof; ii) conjugating the SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4 fragment, derivative or variant thereof to a polypeptide capable of absorptive-mediated or receptor- mediated transcytosis through the subject's blood brain barrier, and / or iii) co-administering the SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4 fragment, derivative or variant thereof with an anti-glucocorticoid drug in a sufficient amount to increase permeability of the subject's blood brain barrier.

[0100] In one aspect, the invention provides a pharmaceutical composition of the invention, wherein the SEQ ID NO. 2, or conservative variant thereof, is chemically modified for enhanced transmembrane transport.

[0101] In one aspect, the invention provides a pharmaceutical composition of the invention, wherein the SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4 or conservative variant thereof, is chemically modified for enhanced transmembrane transport. As used herein, the terms "chemically modified for enhanced transmembrane transport" refer to chemical modifications involving, for example, the glycosylation or the covalent attachment of specific chemical groups, carriers, or moieties to a therapeutic compound in order to increase its lipophilicity, reduce its molecular size or polarity, or facilitate absorptive-mediated or receptor-mediated transport or membrane interaction, thereby improving cellular uptake, bioavailability, or tissue distribution, particularly to target sites such as the central nervous system (CNS). Examples of such chemical modifications include, but are not limited to: (i) lipidation, wherein fatty acid chains are conjugated to enhance membrane permeability; (ii) PEGylation, involving attachment of polyethylene glycol chains to improve solubility and systemic circulation; (iii) prodrug formation, in which polar functional groups are masked with metabolically cleavable linkers to increase passive diffusion; (iv) ligand conjugation, wherein targeting moieties such as transferrin or insulin are used to exploit receptor-mediated transcytosis; and (v) structural modification, such as cyclization or backbone constraint, to enhance metabolic stability and membrane crossing efficiency.

[0102] As used herein, the terms " enhanced transmembrane transport" refer to the improved ability of a chemically modified therapeutic agent to traverse biological membranes — such as the plasma membrane or blood-brain barrier — relative to the corresponding unmodified agent, wherein such enhancement is achieved by increasing lipophilicity, reducing molecular polarity or size, or enabling receptor-mediated or carrier-facilitated uptake, thereby resulting in greater cellular uptake, bioavailability, or tissue-specific distribution.

[0103] In one aspect, the invention provides a pharmaceutical composition of the invention, wherein the SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4 or conservative variant thereof, is chemically modified, for enhanced transmembrane transport, at the C-terminus end of the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4.

[0104] In one aspect, the invention provides a pharmaceutical composition of the invention, wherein the SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4 or conservative variant thereof, is chemically modified, for enhanced transmembrane transport, at the N-terminus end of the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4.

[0105] In one aspect, the invention provides a pharmaceutical composition of the invention, wherein the SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4 or conservative variant thereof, is chemically modified, for enhanced transmembrane transport, at the C-terminus and at the N- terminus end of the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4.

[0106] In one aspect, the sequences of the invention can chemically be modified for enhanced transmembrane transport, for example, by covalent linking of a fatty acid or by glycosylation.

[0107] In one aspect, the invention provides a pharmaceutical composition, wherein the SEQ ID NO. 2, or the conservative variant thereof, is conjugated to a moiety capable of absorptive-mediated or receptor-mediated transcytosis through the subject's blood brain barrier.

[0108] In one aspect, the invention provides a pharmaceutical composition, wherein the SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4 or the conservative variant thereof, is conjugated to a moiety capable of absorptive-mediated or receptor-mediated transcytosis through the subject's blood brain barrier.

[0109] In one aspect, the invention provides a pharmaceutical composition, wherein the SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4 or the conservative variant thereof, is conjugated to a moiety capable of absorptive-mediated transcytosis and to a moiety capable of receptor-mediated transcytosis through the subject's blood brain barrier.

[0110] In one aspect, the invention provides a pharmaceutical composition, wherein the SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4 or the conservative variant thereof, is conjugated at the N- terminus and / or at the C-terminus end of the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4 to a moiety capable of absorptive- mediated or receptor-mediated transcytosis through the subject's blood brain barrier.

[0111] In another aspect, the sequences of the invention can be conjugated to a moiety capable of absorptive-mediated or receptor-mediated transcytosis through the subject's blood brain barrier. In one aspect, the moiety capable of absorptive-mediated or receptor-mediated transcytosis through the subject's blood brain barrier is a peptide, preferably a Cell-Penetrating peptide (CPP).

[0112] In one aspect, the invention provides a pharmaceutical composition, wherein the moiety capable of absorptive-mediated or receptor-mediated transcytosis through the subject's blood brain barrier is a peptide, preferably a Cell-Penetrating peptide (CPP) selected from the group comprising, or consisting of, one or more of HIV -TAT, Penetratin, SynB l / SynB3, polyarginine (e.g. R8, R9), polylysine (e.g., K8, K9), Transportan (chimeric galanin-mastoparan peptide), MAP, Pep-1, MPG (based on HIV gp41 and SV40 NLS), Pep-7 (yeast signal sequence), C105Y, pVEC (from cadherin domain), Antp (Antennapedia fragment), VP22 (derived from Herpes Simplex Virus VP22 protein), Ku70-derived CPPs (e.g., VPTLK), Angiopep-2, SynB peptides (from protegrin analogs), and Bac7 fragments (proline-arginine-rich antimicrobial peptides) or a combination thereof.

[0113] The term “cell-penetrating peptide” (CPP) refers to a peptide sequence capable of translocating across a biological membrane and / or facilitating the intracellular delivery of an attached cargo, which may be a small molecule, nucleic acid, peptide, protein, nanoparticle, or other biologically active agent. CPPs are typically short peptides, e.g., comprising from 5 to about 40 amino acid residues, and may be linear or cyclic, natural or synthetic, or contain D-amino acids, non-natural amino acids, and / or chemical modifications (e.g., PEGylation, lipidation, cyclization). CPPs may exhibit cationic, amphipathic, or hydrophobic character, and may be derived from naturally occurring proteins, engineered sequences, or designed de novo. CPPs may be covalently linked to the sequences of the invention via peptide bonds, disulfide bonds, ester or amide linkages, or via chemical crosslinkers, or may be associated non-covalently, for example through electrostatic or hydrophobic interactions.

[0114] Non-limiting examples of CPPs useful in the present disclosure are selected from the nonlimited group comprising HIV-TAT, Penetratin, SynBl / SynB3, polyarginine (e.g. R8, R9), polylysine (e.g., K8, K9), Transportan (chimeric galanin-mastoparan peptide), MAP, Pep-1, MPG (based on HIV gp41 and SV40 NLS), Pep-7 (yeast signal sequence), C105Y, pVEC (from cadherin domain), Antp (Antennapedia fragment), VP22 (derived from Herpes Simplex Virus VP22 protein), Ku70-derived CPPs (e.g., VPTLK), Angiopep-2, SynB peptides (from protegrin analogs), and Bac7 fragments (proline-arginine-rich antimicrobial peptides) , or a combination thereof (Table 1).

[0115] In one aspect, the invention provides a pharmaceutical composition, wherein the SEQ ID NO. 2, or the conservative variant thereof, is conjugated to a moiety capable of absorptive-mediated or receptor-mediated transcytosis through the subject's blood brain barrier, wherein the moiety comprises a sequence selected from the group comprising, or consisting of, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17, SEQ ID NO: 18, SEQ ID NO: 19, SEQ ID NO: 20, SEQ ID NO: 21, SEQ ID NO: 22, SEQ ID NO: 23, SEQ ID NO: 24, and SEQ ID NO: 25, or a combination thereof. In one embodiment, the invention provides a pharmaceutical composition, wherein the SEQ ID NO. 2, or the conservative variant thereof, is conjugated to a moiety capable of absorptive- mediated or receptor-mediated transcytosis through the subject's blood brain barrier, wherein the moiety comprises a sequence selected from the group comprising, or consisting of, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17, SEQ ID NO: 18, SEQ ID NO: 19, SEQ ID NO: 20, SEQ ID NO: 21, SEQ ID NO: 22, SEQ ID NO: 23, SEQ ID NO: 24, and SEQ ID NO: 25, or a combination thereof, wherein one or more moiety is conjugated at the C-terminal end and / or at the N-terminal end of SEQ ID NO. 2, or the conservative variant thereof.

[0116] In one aspect, the invention provides a pharmaceutical composition, wherein the moiety capable of absorptive-mediated transcytosis is a peptide selected from the group comprising, or consisting of, one or more of a p97 (melanotransferrin) polypeptide, a Receptor Associated Protein (RAP), an aprotinin peptide or an analog thereof, a protein transduction domain (PTD), a human low-density lipoprotein receptor (hLDLR) binding peptide or an analog thereof, an antibody or natural ligand that binds to a BBB-associated receptor, and glutathione (GSH), or a combination thereof.

[0117] In one aspect, the invention provides a pharmaceutical composition, wherein the SEQ ID NO. 2, or the conservative variant thereof, is conjugated to a moiety capable of absorptive-mediated transcytosis, wherein the moiety is a peptide sequence selected from the group comprising, or consisting of, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, and SEQ ID NO: 31 or a combination thereof.

[0118] In one aspect, the invention provides a pharmaceutical composition, wherein the SEQ ID NO. 2, or the conservative variant thereof, is conjugated to a moiety capable of absorptive-mediated transcytosis, wherein the moiety is a peptide sequence selected from the group comprising, or consisting of, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, and SEQ ID NO: 31 or a combination thereof, wherein one or more moiety is conjugated at the C-terminal end and / or at the N-terminal end of SEQ ID NO. 2, or the conservative variant thereof.

[0119] In one aspect, the sequences of the invention can be conjugated to a moiety that is a polypeptide capable of absorptive-mediated. Non-limiting examples of polypeptides capable of absorptive- mediated transcytosis are selected from the group comprising one or more of a p97 (mel anotransferrin) polypeptide, a Receptor Associated Protein (RAP), an aprotinin peptide or an analog thereof, a protein transduction domain (PTD), a human low-density lipoprotein receptor (hLDLR) binding peptide or an analog thereof, an antibody or natural ligand that binds to a BBB-associated receptor, and glutathione (GSH), or a combination thereof (Table 2).

[0120] In one aspect, the invention provides a pharmaceutical composition, wherein the moiety capable of receptor-mediated transcytosis is a receptor selected from the group comprising, or consisting of, one or more of the insulin receptor, the transferrin receptor, the leptin receptor, lipoprotein receptors such as the lipoprotein receptor-related protein (LRP-1) receptor, insulinlike growth factor (IGF) receptors such as IGF1R and IGF2R, the low-density lipoprotein receptor (e.g. Low-Density Lipoprotein Receptor-Related Protein 1), the diptheria toxin receptor, LRP1 receptor and TMEM 30A (Flippase), or a combination thereof.

[0121] In one aspect, the the sequences of the invention can be conjugated to a moiety that is a polypeptide capable of receptor-mediated transcytosis through the subject's blood brain barrier. Non-limiting examples of a polypeptides capable of receptor-mediated transcytosis are selected from the group comprising one or more of the insulin receptors, the transferrin receptor, the leptin receptor, lipoprotein receptors such as the lipoprotein receptor-related protein (LRP-1) receptor, insulin-like growth factor (IGF) receptors such as IGF1R and IGF2R, the low-density lipoprotein receptor, the diptheria toxin receptor, and TMEM 30A (Flippase).

[0122] In one aspect, the invention provides a pharmaceutical composition, wherein the moiety capable of receptor-mediated transcytosis is a ligand selected from the group comprising, or consisting of, one or more of insulin, transferrin and transferrin fragments, lactoferrin and lactoferrin fragments, apolipoprotein A (Apo A), apolipoprotein B (Apo B), apolipoprotein E (Apo E), Angiopep-2 and diptheria toxin (including non-toxic mutants thereof such as CRM45 and CRM 197), or a combination thereof.

[0123] In another aspect, the polypeptide capable of receptor-mediated transcytosis is a ligand selected from the group comprising one or more of insulin, transferrin and transferrin fragments, lactoferrin and lactoferrin fragments, apolipoprotein A (Apo A), apolipoprotein B (Apo B), apolipoprotein E (Apo E), and diptheria toxin (including non-toxic mutants thereof such as CRM45 and CRM 197).

[0124] In one aspect, the invention provides a pharmaceutical composition, wherein the moiety capable of absorptive-mediated transcytosis is selected from the group comprising, or consisting of, one or more of a palmitoyl or myristoyl group, cholesterol, polyethylene glycol (PEG), Glucose / mannose, and D-glutamate, or a combination thereof.

[0125] In another aspect, the moiety capable of absorptive-mediated transcytosis is selected from the group comprising one or more of a palmitoyl or myristoyl group, cholesterol, polyethylene glycol (PEG), Glucose / mannose, and D-glutamate, or a combination thereof.

[0126] In one aspect, the invention provides a pharmaceutical composition, wherein the moiety capable of absorptive-mediated transcytosis is selected from the group comprising a nanoparticle, a lipid-based nanoparticle or a carrier attachment moiety.

[0127] In another aspect, the moiety capable of absorptive-mediated transcytosis is selected from the group comprising a nanoparticle, a lipid-based nanoparticle or a carrier attachment moiety

[0128] Suitable nanoparticles include, without limitation, metal nanoparticles such as gold, silver, and iron oxide nanoparticles; quantum dots; polymer-based nanoparticles including those composed of poly(lactic-co-glycolic acid) (PLGA) or polyethylene glycol (PEG)-modified polymers; and dendrimers.

[0129] Lipid-based nanoparticles encompassed by the invention include liposomes, solid lipid nanoparticles, nanostructured lipid carriers, lipid nanocapsules, and naturally derived or synthetic exosomes or exosome-mimetic vesicles.

[0130] Carrier attachment moieties may comprise antibody fragments or single-chain variable fragments (scFv) directed to absorptive receptors, and aptamers capable of receptor binding and mediating transcytosis. The moiety is conjugated, either covalently or non-covalently, to the peptides of the invention.

[0131] In one aspect, the invention provides a pharmaceutical composition, wherein said composition is co-administered with an anti-glucocorticoid drug in a sufficient amount to increase permeability of the subject's blood brain barrier. In certain embodiments, antiglucocorticoid drugs may modulate the permeability of the blood-brain barrier (BBB) by interfering with glucocorticoid signaling pathways or cortisol biosynthesis. Such antiglucocorticoid drugs of the invention may include mifepristone, a glucocorticoid receptor (GR) antagonist capable of increasing BBB permeability through disruption of tight junction regulation; relacorilant, a selective GR modulator that may similarly affect BBB integrity in a receptor-specific manner; ketoconazole and levoketoconazole, which inhibit steroidogenic enzymes and reduce systemic cortisol levels, thereby potentially impairing glucocorticoid- mediated maintenance of BBB function; osilodrostat and etomidate, which inhibit 110- hydroxylase and suppress cortisol synthesis, leading to possible indirect effects on BBB permeability; and mitotane, an adrenolytic compound that induces prolonged cortisol deficiency, which may result in diminished BBB stability over time.

[0132] As used herein, the term "co-administration" refers to the administration of two or more pharmacologically active agents, either simultaneously, sequentially, or within a defined time window, in such a manner that their respective therapeutic effects, pharmacokinetics, or pharmacodynamics may interact or be complementary. The co-administered agents may be administered via the same or different routes of administration, in a single combined formulation or as separate formulations, and may be intended to act synergistically, additively, or to mitigate adverse effects associated with one or more of the agents.

[0133] As used herein, the terms " increase permeability of the subject's blood brain barrier " refer to the enhancement of the transport capacity through the BBB, thereby facilitating the passage of therapeutic agents from the systemic circulation into the central nervous system (CNS), typically by modulating tight junction integrity, endothelial cell function, or transcytotic pathways.

[0134] In one aspect, the pharmaceutical composition of the invention is for use in the treatment and / or prevention of a disorder or disease related to the hippocampus. Preferably, said disorder or disease related to the hippocampus is selected form the group comprising a neurodevelopmental, a neurological or a psychiatric disorder or disease.

[0135] In one aspect, the invention provides a pharmaceutical composition, wherein the neurodevelopmental, neurological or psychiatric disorder or disease related to the hippocampus is selected from the group comprising, or consisting of, one or more of schizophrenia, for example of the paranoid, disorganized, catatonic, undifferentiated, or residual type; schizophreniform disorder; schizoaffective disorder, for example of the delusional type or the depressive type, cognitive impairment associated with schizophrenia (CIAS), bipolar disorder, ADHD, anxiety, anxiety- related disorders, depression, cognitive dysfunction, borderline personality disorder (BPD), depression or cognitive impairment induced by cytokines or chemotherapies administration, inflammation-related cognitive impairment or mood impairment, Alzheimer’s disease, Parkinson's disease, post-traumatic stress disorder, frontal temporal dementia, dementia, memory -related disorders, chronic pain, sleep and circadian disorders and sleep disruption, Cushing's Syndrome, Addison's Disease, Congenital Adrenal Hyperplasia (CAH), Secondary Adrenal Insufficiency, Hypothalamic- Pituitary-Adrenal (HP A) Axis Dysfunction. Ectopic ACTH Syndrome, Glucocorticoid Resistance Syndrome, Adrenal Carcinoma, or a combination thereof.

[0136] As used herein, the term “disorder or disease related to the hippocampus” refers to any disorder, condition, or disease characterized by pathological alterations, dysfunction, or impairment of the hippocampus, including but not limited to changes in hippocampal anatomy, physiology, or connectivity. Such disorders or diseases encompass neurodevelopmental, neurological, and psychiatric conditions wherein the hippocampus contributes to the etiology, progression, or symptomatology of the disorder or disease.

[0137] According to the present invention, the neurodevelopmental, neurological or psychiatric disorder or disease is selected from the group comprising epilepsy, schizophrenia, for example of the paranoid, disorganized, catatonic, undifferentiated, or residual type; schizophreniform disorder; schizoaffective disorder, for example of the delusional type or the depressive type, cognitive impairment associated with schizophrenia (CIAS), autism spectrum disorder, bipolar disorder, ADHD, anxiety, anxiety- related disorders, depression, cognitive dysfunction, borderline personality disorder (BPD), depression or cognitive impairment induced by cytokines or chemotherapies administration, inflammation-related cognitive impairment or mood impairment, Alzheimer’s disease, Parkinson's disease, Fragile X syndrome, post- traumatic stress disorder, frontal temporal dementia, dementia, memory-related disorders, amyotrophic lateral sclerosis(ALS), chronic pain, hearing loss, sleep and circadian disorders and sleep disruption, Cushing's Syndrome, Addison's Disease, Congenital Adrenal Hyperplasia (CAH), Secondary Adrenal Insufficiency, Hypothalamic-Pituitary-Adrenal (HPA) Axis Dysfunction. Ectopic ACTH Syndrome, Glucocorticoid Resistance Syndrome, Adrenal Carcinoma, or a combination of one or more thereof.

[0138] The present invention further provides a C-terminal fragment of the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof.

[0139] In one aspect, the variant is a conservative variant of the Astrocytic phosphoprotein (PEA-15) as set forth in SEQ ID NO:2, sharing at least 50%, 70%, 80%, 90%, or 95% sequence homology, such as 95%, 96%, 97%, 98%, or 99%, with SEQ ID NO. 2. In one aspect, the present invention provides a C-terminal fragment of the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4 or a conservative variant thereof.

[0140] In one aspect, the variant is a conservative variant of the Astrocytic phosphoprotein (PEA-15) as set forth in SEQ ID NO:2, SEQ ID NO. 3 or SEQ ID NO. 4 sharing at least 50%, 70%, 80%, 90%, or 95% sequence homology, such as 95%, 96%, 97%, 98%, or 99%, with SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4.

[0141] In one aspect, the invention provides a C-terminal fragment of the Astrocytic phosphoprotein (PEA-15) protein comprising, or consisting of a sequence as set forth in SEQ ID NO: 2.

[0142] In one aspect, the invention provides a C-terminal fragment of the Astrocytic phosphoprotein (PEA-15) protein comprising, or consisting of a sequence as set forth in SEQ ID NO: 2, wherein the C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein comprises at least one, at least two, at least three, at least four, at least 5, or at least 6 amino acid substitution(s). In certain embodiments, the C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein comprises no more than 1, no more than 2, no more than 3, no more than 4, no more than 5, or no more than 6 amino acid substitutions relative to the sequence consisting of: SEQ ID NO: 2.

[0143] In one aspect, the invention provides a C-terminal fragment of the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, of the invention, wherein the PEA- 15 protein, or variant thereof is

[0144] (a) chemically modified for enhanced transmembrane transport, and / or

[0145] (b) conjugated to a moiety capable of absorptive-mediated or receptor-mediated transcytosis through a subject's blood brain barrier.

[0146] In one aspect, the invention provides a C-terminal fragment of the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4 or a conservative variant thereof, of the invention, wherein the PEA- 15 protein, or variant thereof is

[0147] (a) chemically modified for enhanced transmembrane transport, and / or

[0148] (b) conjugated to a moiety capable of absorptive-mediated or receptor-mediated transcytosis through a subject's blood brain barrier. In one aspect, the invention provides a C-terminal fragment of the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, of the invention, wherein the PEA- 15 protein, or variant thereof is

[0149] (a) chemically modified for enhanced transmembrane transport, and / or

[0150] (b) conjugated to a moiety capable of absorptive-mediated or receptor-mediated transcytosis through a subject's blood brain barrier, wherein the moiety is a sequence selected from the group comprising, or consisting of, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17, SEQ ID NO: 18, SEQ ID NO: 19, SEQ ID NO: 20, SEQ ID NO: 21, SEQ ID NO: 22, SEQ ID NO: 23, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, and SEQ ID NO: 31, or a combination thereof.

[0151] In one aspect, the invention provides a C-terminal fragment of the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, of the invention, wherein the PEA- 15 protein, or variant thereof is

[0152] (a) chemically modified for enhanced transmembrane transport, and / or

[0153] (b) conjugated to a moiety capable of absorptive-mediated or receptor-mediated transcytosis through a subject's blood brain barrier, wherein the moiety is a sequence selected from the group comprising, or consisting of, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17, SEQ ID NO: 18, SEQ ID NO: 19, SEQ ID NO: 20, SEQ ID NO: 21, SEQ ID NO: 22, SEQ ID NO: 23, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, and SEQ ID NO: 31, or a combination thereof, wherein one or more moiety is conjugated at the C-terminal end and / or at the N-terminal end of SEQ ID NO. 2, or the conservative variant thereof.

[0154] As used herein, the terms "chemically modified for enhanced transmembrane transport" refer to chemical modifications involving, for example, the glycosylation or the covalent attachment of specific chemical groups, carriers, or moieties to a therapeutic compound in order to increase its lipophilicity, reduce its molecular size or polarity, or facilitate absorptive-mediated or receptor-mediated transport or membrane interaction, thereby improving cellular uptake, bioavailability, or tissue distribution, particularly to target sites such as the central nervous system (CNS). Examples of such chemical modifications include, but are not limited to: (i) lipidation, wherein fatty acid chains are conjugated to enhance membrane permeability; (ii) PEGylation, involving attachment of polyethylene glycol chains to improve solubility and systemic circulation; (iii) prodrug formation, in which polar functional groups are masked with metabolically cleavable linkers to increase passive diffusion; (iv) ligand conjugation, wherein targeting moieties such as transferrin or insulin are used to exploit receptor-mediated transcytosis; and (v) structural modification, such as cyclization or backbone constraint, to enhance metabolic stability and membrane crossing efficiency.

[0155] As used herein, the terms " enhanced transmembrane transport" refer to the improved ability of a chemically modified therapeutic agent to traverse biological membranes — such as the plasma membrane or blood-brain barrier — relative to the corresponding unmodified agent, wherein such enhancement is achieved by increasing lipophilicity, reducing molecular polarity or size, or enabling receptor-mediated or carrier-facilitated uptake, thereby resulting in greater cellular uptake, bioavailability, or tissue-specific distribution.

[0156] As used herein, the terms "Conjugated to a moiety" refer to the covalent or non-covalent attachment of a molecule, compound, or substance (such as a therapeutic agent, diagnostic agent, or carrier) to another distinct chemical entity (the "moiety"), wherein the moiety imparts a desired functional property, such as targeting, transport, stability, solubility, or bioavailability. The conjugation of the present invention may be achieved through chemical bonding (e.g., via amide, ester, thioether, disulfide, or other linkages), through the use of a cleavable or non-cleavable linker, or via physical interactions such as electrostatic, hydrophobic, or affinity -based associations, provided that the resulting complex is sufficiently stable under physiological conditions to exert the intended effect. The terms "Conjugated to a moiety" include both direct conjugation (where the compound and moiety are joined without an intervening structure) and indirect conjugation (where a linker or spacer molecule connects the molecule, compound, or substance and the moiety). Unless otherwise specified, "conjugated to a moiety" encompasses mono-, di-, and multi-valent conjugates, and includes linear, branched, or cyclic configurations.

[0157] As used herein, the terms "Absorptive-mediated or receptor-mediated transcytosis through a subject's blood brain barrier" refer to the transcellular transport of molecules across the blood-brain barrier (BBB), mediated by intracellular vesicular trafficking within brain endothelial cells, and initiated by either:

[0158] (a) Receptor-mediated transcytosis, wherein a molecule or conjugate specifically binds to a receptor expressed on the luminal surface of brain capillary endothelial cells (such as transferrin receptor, insulin receptor, or low-density lipoprotein receptor), resulting in endocytosis, intracellular vesicular transport, and exocytosis at the abluminal (brain-facing) surface; or

[0159] (b) Absorptive-mediated transcytosis, wherein transport is initiated by non-specific electrostatic or hydrophobic interactions — typically involving cationic moieties — with the luminal membrane, leading to endocytosis and subsequent transcellular passage to the brain parenchyma.

[0160] Absorptive-mediated or receptor-mediated transcytosis enable the delivery of agents (proteins, peptides or nucleic acids) of the invention across the BBB into the central nervous system (CNS), bypassing the restrictive paracellular tight junctions characteristic of the BBB.

[0161] The present invention further provides a nucleic acid encoding a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, of the invention, or a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, conjugated to a moiety capable of absorptive-mediated or receptor-mediated transcytosis through a subject's blood brain barrier of the invention.

[0162] In one aspect, the invention provides a nucleic acid encoding a C-terminal fragment of the Astrocytic phosphoprotein (PEA-15) protein comprising, or consisting of a sequence as set forth in SEQ ID NO. 2, or a conservative variant thereof, of the invention, or a C-terminal fragment of the Astrocytic phosphoprotein (PEA-15) protein comprising, or consisting of a sequence as set forth in SEQ ID NO. 2, or a conservative variant thereof, conjugated to a moiety capable of absorptive-mediated or receptor-mediated transcytosis through a subject's blood brain barrier of the invention.

[0163] In one aspect, the invention further provides a nucleic acid encoding a C-terminal fragment of the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4 or a conservative variant thereof, of the invention, or a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4 or a conservative variant thereof, conjugated to a moiety capable of absorptive-mediated or receptor-mediated transcytosis through a subject's blood brain barrier of the invention.

[0164] As used herein, the term “nucleic acid” refers to a natural or synthetic molecule comprising a single nucleotide or two or more nucleotides linked by a phosphate group at the 3' position of one nucleotide to the 5' end of another nucleotide. The nucleic acid is not limited by length, and thus, the nucleic acid can include deoxyribonucleic acid (DNA) or ribonucleic acid (RNA). The term nucleic acid also comprises DNA molecules including genomic DNA, comprising both coding and non-coding regions, wherein coding regions encode proteins and non-coding DNA includes introns, regulatory elements, and structural sequences such as telomeric, centromeric, and satellite DNA. Other forms of DNA include complementary DNA (cDNA) synthesized from RNA templates, mitochondrial DNA (mtDNA) and chloroplast DNA (cpDNA) of organellar origin, as well as extrachromosomal DNA (ecDNA) such as plasmids and circular DNAs, which may play roles in gene regulation, replication, or amplification. The term nucleic acid also comprises examples of RNAs or RNA molecules (included within total RNA) such as but not limited to: mRNA, amplicons, rRNA, tRNA, nRNA, siRNA, snRNA, snoRNA, scaRNA, microRNA, dsRNA, ncRNA (e.g. IncRNA), truncated RNA, ribozyme, riboswitch and viral RNA (e.g., retroviral RNA).

[0165] In one embodiment, the invention provides a DNA or cDNA molecule encoding a C-terminal fragment of the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, of the invention, or a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, conjugated to a moiety capable of absorptive-mediated or receptor-mediated transcytosis through a subject's blood brain barrier of the invention.

[0166] In one embodiment, the invention provides an mRNA molecule encoding a C-terminal fragment of the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, of the invention, or a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, conjugated to a moiety capable of absorptive-mediated or receptor-mediated transcytosis through a subject's blood brain barrier of the invention. As used herein, the terms “Oligonucleotide” or “polynucleotide,” which are used synonymously, means a linear polymer of natural or modified nucleosidic monomers linked by phosphodiester bonds or analogs thereof. The term “oligonucleotide” usually refers to a shorter polymer, e.g., comprising from about 3 to about 100 monomers, and the term “polynucleotide” usually refers to longer polymers, e.g., comprising from about 100 monomers to many thousands of monomers, e.g., 10,000 monomers, or more. Oligonucleotides and polynucleotides may be natural or synthetic. Oligonucleotides and polynucleotides include deoxyribonucleosides, ribonucleosides, and non-natural analogs thereof, such as anomeric forms thereof, peptide nucleic acids (PNAs), and the like, provided that they are capable of specifically binding to a target genome by way of a regular pattern of monomer-to-monomer interactions, such as Watson-Crick type of base pairing, base stacking, Hoogsteen or reverse Hoogsteen types of base pairing, or the like.

[0167] The terms “peptide”, “protein”, and “polypeptide” are used interchangeably to refer to a natural or synthetic molecule comprising two or more amino acids linked by the carboxyl group of one amino acid to the alpha amino group of another.

[0168] The present invention further provides a vector comprising the nucleic acid of the invention.

[0169] The term "vector", as used herein, refers to a delivery vehicle capable of introducing one or more polynucleotides into a host cell via transduction or transfection, and includes both viral and non- viral vectors. The vectors of the invention may target cells of the central nervous system (CNS) or the blood-brain barrier (BBB), such as, but not limited to, brain endothelial cells, for the local production of therapeutic proteins or peptides or composition of the invention within the CNS, preferably within the brain parenchyma. In certain embodiments, brain endothelial cells, astrocytes, and / or pericytes serve as reservoirs for sustained and high- quality expression of therapeutic proteins or peptides or composition of the invention for the treatment of CNS-related disorders.

[0170] Non-viral vectors include, without limitation, organic nanomaterials such as liposomes, exosomes, dendrimers, and micelles, and inorganic nanomaterials such as gold nanoparticles, silica nanoparticles, and carbon nanotubes. In one embodiment, the surface of the non-viral vector comprises a targeting moiety, such as a peptide, small molecule, therapeutic proteins or peptides or composition of the invention, antibody fragment, oligonucleotide, aptamer, lipid, nanoparticle, or cationic molecule, which facilitates specific delivery to BBB- associated cells. The terms "viral vectors", as used herein, include both wild-type and engineered (e.g., modified or recombinant) viruses, and encompass vectors derived from adeno-associated virus (AAV), adenovirus, retrovirus, rhinovirus, lentivirus, hepatitis virus, herpes simplex virus (HSV), and virus-like particles (VLPs). VLPs refer to multiprotein structures that mimic the organization and conformation of native viruses but lack a viral genome, as is well understood in the art. In one embodiment, the viral vector is an AAV, based on the unexpected finding that AAV-mediated transduction of brain endothelial cells results in the local secretion of high-quality and high-quantity therapeutic proteins or peptides or composition of the invention into the central nervous system (CNS), preferably into the brain parenchyma.

[0171] The AAV vector may be derived from any suitable naturally occurring or engineered serotype, including, but not limited to, AAV1, AAV2, AAV3, AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, AAV10, AAV11, AAV12, and AAVrhlO. Additional naturally occurring AAVs with CNS tropism include AAVrh8, AAVrh39, AAVrh43, and members of the AAVHSC family (e.g., AAVHSC7, AAVHSC715, AAVHSC717). Engineered AAVs with enhanced BBB penetration may also be used, such as AAV -XI, AAV-PHP.B, AAV-PHP.eB, AAV-PHP.eC, AAV -BRI, and chimeric or transwell-selected capsids optimized for human BBB transport. In certain embodiments, preferred AAV vectors include AAV2, AAV8, AAV9, AAV 10, and AAVrhlO.

[0172] In certain embodiments, the vector of the invention may specifically target cells of the bloodbrain barrier (BBB) and / or the central nervous system (CNS). In alternative embodiments, the vector does not exhibit such specificity and may transduce peripheral tissues. In the case of non-specific vectors, BBB-specific or CNS-specific promoters may be employed to drive preferential or predominant expression of a polynucleotide encoding a therapeutic proteins or peptides or composition of the invention in BBB or CNS cell types.

[0173] In one embodiment, the polynucleotide comprises a GFAP (Glial fibrillary acidic protein) promoter, optionally in combination with a CMV (cytomegalovirus) early enhancer, operably linked to a polynucleotide encoding a therapeutic protein or peptide or composition of the invention. This results in preferential expression in astrocytes. In another embodiment, the promoter is selected from ATP1A2 (Sodium / potassium-transporting ATPase subunit alpha- 2), CLDN5 (Claudin-5), ADRB2 (Beta-2 adrenergic receptor), or TNFRSF6B (Tumor necrosis factor receptor superfamily member 6B), optionally with a CMV early enhancer, to drive expression in BBB endothelial cells.

[0174] In a further embodiment, the promoter is selected from PDYN (Proenkephalin-B), GH1 (Growth hormone 1), or OPALIN, enabling expression in brain parenchymal cells. In another embodiment, the promoter is selected from SYN1 (Synapsin-1), CAMK2A (Calcium / calmodulin-dependent protein kinase type II subunit alpha), NEFH (Neurofilament heavy subunit), or NEUR0D6 (Neurogenic differentiation factor 6) for neuron-specific expression. In yet another embodiment, an OLIG2 (Oligodendrocyte transcription factor 2) promoter, optionally linked to a CMV enhancer, is used for expression in oligodendrocytes.

[0175] Promoters suitable for use with the therapeutic protein or peptide or composition of the invention may include, but are not limited to:

[0176] BBB-specific promoters: Slcolcl (Solute carrier organic anion transporter family member 1C1), Mfsd2a (Sodium-dependent lysophosphatidylcholine symporter 1), Glutl (Glucose transporter 1), Cdh5 (VE-cadherin), ABCB1 (p-gly coprotein 1), Transferrin receptor (TfR), endothelial specific receptor tyrosine kinase (Tie2).

[0177] CNS-specific promoters: Synapsin I (SYN1), CamKIIa (Calcium / calmodulin-dependent protein kinase type II subunit alpha), GFAP (Glial fibrillary acidic protein), MBP (Myelin basic protein), PLP (Myelin proteolipid protein), TH (Tyrosine hydroxylase), ChAT (Choline acetyltransferase), GAD65 / 67 (Glutamate decarboxylase 65 / 67), L7 / PCP2 (Purkinje cell protein 2 (L7)), 0LIG2 (Oligodendrocyte transcription factor 2).

[0178] Broadly active promoters (where cell-specificity is conferred by additional elements): CAG, EFla (Elongation factor 1-alpha), PGK (Phosphoglycerate kinase 1), CBh (chicken P-actin hybrid).

[0179] The above-mentioned promoters may be used to ensure targeted expression of the therapeutic protein or peptide or composition of the invention encoded by the vector comprising the nucleic acid of the invention, thereby enhancing efficacy and limiting off-target effects.

[0180] The invention further provides a composition comprising:

[0181] (a) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, of the invention, (b) a nucleic acid of the invention, or

[0182] (c) a vector of the invention.

[0183] In one aspect, the invention provides a composition comprising, or consisting of:

[0184] (a) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, of the invention,

[0185] (b) a nucleic acid of the invention, or

[0186] (c) a vector of the invention.

[0187] In one aspect, the invention provides a composition comprising, or consisting of:

[0188] (a) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, of the invention,

[0189] (b) a nucleic acid of the invention, and

[0190] (c) a vector of the invention.

[0191] In one aspect, the invention provides a composition comprising, or consisting of:

[0192] (a) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4 or a conservative variant thereof, of the invention,

[0193] (b) a nucleic acid of the invention, and / or

[0194] (c) a vector of the invention.

[0195] The invention further provides a pharmaceutical composition comprising:

[0196] (a) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, of the invention,

[0197] (b) a nucleic acid of the invention, or (c) a vector of the invention, and a pharmaceutically acceptable carrier and / or diluent.

[0198] In one aspect, the invention provides a pharmaceutical composition comprising, or consisting of:

[0199] (a) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, of the invention,

[0200] (b) a nucleic acid of the invention, or

[0201] (c) a vector of the invention, and a pharmaceutically acceptable carrier and / or diluent.

[0202] In one aspect, the invention provides a pharmaceutical composition comprising, or consisting of:

[0203] (a) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, of the invention,

[0204] (b) a nucleic acid of the invention, and

[0205] (c) a vector of the invention, and a pharmaceutically acceptable carrier and / or diluent.

[0206] In one aspect, the invention provides a pharmaceutical composition comprising, or consisting of:

[0207] (a) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4 or a conservative variant thereof, of the invention,

[0208] (b) a nucleic acid of the invention, and / or

[0209] (c) a vector of the invention, and a pharmaceutically acceptable carrier and / or diluent.

[0210] In certain embodiments, the composition and / or the pharmaceutical composition of the invention comprising (i) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, (ii) a nucleic acid encoding said fragment, and (iii) a vector comprising said nucleic acid is administered in a single step to achieve therapeutic effects in the central nervous system (CNS). The components may be co-formulated and delivered simultaneously, for example, via intravenous or intrathecal injection, provided that the formulation is capable of facilitating blood-brain barrier (BBB) penetration or is administered directly into the CNS (e.g., via intrathecal, intracerebroventricular, or intraparenchymal injection). The C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof may exert a rapid pharmacological effect upon entry into the CNS, such as neuroprotection, receptor modulation, or anti-inflammatory activity. Concurrently, the nucleic acid, delivered via the vector, enables sustained in situ expression of the therapeutic peptide in neuronal or glial cells, thereby extending the duration of therapeutic action. The use of BBB-penetrant delivery vectors, such as adeno-associated virus (AAV) serotypes with CNS tropism or engineered lipid nanoparticles, may enhance delivery efficiency. The single-step approach offers advantages in terms of reduced procedural complexity, improved patient compliance, and synchronized pharmacodynamic profiles between the exogenously administered peptide fragment and endogenously expressed peptide fragment.

[0211] Alternatively, the composition and / or the pharmaceutical composition of the invention may be administered in two or more steps, wherein the C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, the nucleic acid, and / or the vector are delivered separately, either at different time points or via different routes of administration. In one embodiment, the C-terminal peptide fragment is administered systemically or directly into the CNS to elicit an immediate therapeutic effect, followed by administration of the vector-nucleic acid complex to enable sustained CNS expression of the C-terminal peptide fragment. In another embodiment, the nucleic acid / vector is first administered to transduce target CNS cells, and the C-terminal peptide fragment is later administered to potentiate the therapeutic response or act synergistically. A three-step administration may be employed to address pharmacokinetic or stability challenges, or to temporally separate CNS delivery events to minimize immunogenicity or toxicity. For example, pre-conditioning the BBB to enhance permeability prior to vector administration, followed by the C-terminal peptide fragment administration, may optimize therapeutic outcomes.

[0212] Each administration strategy presents distinct advantages. Single-step administration simplifies delivery logistics and ensures co-localization of components, which is particularly advantageous for acute CNS conditions. Multi-step regimens, by contrast, offer greater flexibility in timing, dose optimization, and modulation of therapeutic windows, which may be beneficial in chronic or progressive neurological disorders. The selection of administration strategy may be guided by the pharmacological profile of the C-terminal peptide fragment, the vector’s transduction efficiency in CNS tissues, and the ability of each component to traverse or bypass the BBB effectively.

[0213] The invention further provides a method of treatment and / or prevention of a neurodevelopmental, a neurological or a psychiatric disorder or disease related to the hippocampus, comprising administering

[0214] (a) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or conservative variant thereof, of the invention,

[0215] (b) a nucleic acid of the invention,

[0216] (c) a vector of the invention, or

[0217] (d) a pharmaceutical composition of the invention.

[0218] In one aspect, the invention provides a method of treatment and / or prevention of a neurodevelopmental, a neurological or a psychiatric disorder or disease related to the hippocampus, comprising, or consisting of administering

[0219] (a) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or conservative variant thereof, of the invention,

[0220] (b) a nucleic acid of the invention, (c) a vector of the invention, or

[0221] (d) a pharmaceutical composition of the invention.

[0222] In one aspect, the invention provides a method of treatment and / or prevention of a neurodevelopmental, a neurological or a psychiatric disorder or disease related to the hippocampus, comprising, or consisting of administering

[0223] (a) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or conservative variant thereof, of the invention,

[0224] (b) a nucleic acid of the invention,

[0225] (c) a vector of the invention, and

[0226] (d) a pharmaceutical composition of the invention.

[0227] In one aspect, the invention provides a method of treatment and / or prevention of a neurodevelopmental, a neurological or a psychiatric disorder or disease related to the hippocampus, comprising, or consisting of administering

[0228] (a) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4 or conservative variant thereof, of the invention,

[0229] (b) a nucleic acid of the invention,

[0230] (c) a vector of the invention, and / or

[0231] (d) a pharmaceutical composition of the invention.

[0232] The present invention further contemplates methods of treatment and / or prevention of neurodevelopmental, neurological or psychiatric disorder or disease in a subject in need thereof.

[0233] In one aspect, the method of treatment and / or prevention comprises (a) providing an agent of the invention and (b) administering said agent to a subject in need thereof. In one aspect, the agent is a peptide of the invention. Preferably, said agent is in the form of a pharmaceutical composition comprising a therapeutically effective amount of the agent (e.g. a peptide or nucleic acid encoding the peptide of the invention) as described herein.

[0234] Administration of the agents and / or pharmaceutical compositions described herein may be accomplished by any acceptable method which allows the agents of the invention to reach its target. The particular mode selected will depend of course, upon factors such as the particular formulation, the severity of the state of the subject being treated, and the dosage required for therapeutic efficacy. The actual effective amounts of agent (the "drug") can vary according to the specific drug or combination thereof being utilized, the particular composition formulated, the mode of administration, and the age, weight, condition of the patient, and severity of the symptoms or condition being treated.

[0235] The administration may be localized (i.e. , to a particular region, physiological system, tissue, organ, or cell type) or systemic, depending on the condition being treated.

[0236] Intranasal route is also envisioned to deliver the agents and / or pharmaceutical compositions of the invention as it possesses the ability to pass through the blood brain barrier (BBB) using nose-to-brain pathways.

[0237] Injections can be e.g., intravenous, intradermal, intracranial (e.g. intracerebroventricular) subcutaneous, intramuscular, or intraperitoneal.

[0238] Injections can be given at multiple locations. Implantation includes inserting implantable drug delivery systems, e.g., microspheres, hydrogels, polymeric reservoirs, cholesterol matrixes, polymeric systems, e.g., matrix erosion and / or diffusion systems and non-polymeric systems, e.g., compressed, fused, or partially-fused pellets. Inhalation includes administering the composition with an aerosol in an inhaler, either alone or attached to a carrier that can be absorbed. For systemic administration, it may be preferred that the agents and / or pharmaceutical compositions are encapsulated in liposomes.

[0239] Preferably, the agents and / or pharmaceutical compositions of the invention delivery systems are provided in a manner which enables tissue-specific uptake of the agents and / or pharmaceutical compositions delivery systems. Techniques include using tissue or organ localizing devices, such as wound dressings or transdermal delivery systems, using invasive devices such as vascular or urinary catheters, and using interventional devices such as stents having drug delivery capability and configured as expansive devices or stent grafts.

[0240] The agents and / or pharmaceutical compositions may be delivered using a bio-erodible implant by way of diffusion or by degradation of the polymeric matrix.

[0241] The administration of the agents and / or pharmaceutical compositions of the invention may be designed so as to result in sequential exposures to the agents and / or pharmaceutical compositions over a certain time period, for example, hours, days, weeks, months or years. This may be accomplished, for example, by repeated administrations of a formulation or by a sustained or controlled release delivery system in which the agents and / or pharmaceutical compositions is / are delivered over a prolonged period without repeated administrations. Administration of the formulations using such a delivery system may be, for example, by oral dosage forms, bolus injections, transdermal patches or subcutaneous implants (see e.g. Nance, E., Pun, S.H., Saigal, R. et al. Drug delivery to the central nervous system. Nat Rev Mater 7, 314-331 (2022)). Maintaining a substantially constant concentration of the composition may be preferred in some cases.

[0242] Other delivery systems suitable include, but are not limited to, time-release, delayed release, sustained release, or controlled release delivery systems. Such systems may avoid repeated administrations in many cases, increasing convenience to the subject and the physician. Many types of release delivery systems are available and known to those of ordinary skill in the art. They include, for example, polymer-based systems such as polylactic and / or poly glycolic acids, polyanhydrides, polycaprolactones, copolyoxalates, polyesteramides, polyorthoesters, polyhydroxybutyric acid, and / or combinations of these. Microcapsules of the foregoing polymers containing nucleic acids are described in, for example, U.S. Patent No. 5,075,109. Other examples include nonpolymer systems that are lipid-based including sterols such as cholesterol, cholesterol esters, and fatty acids or neutral fats such as mono-, di- and triglycerides; hydrogel release systems; liposome-based systems; phospholipid based-systems; silastic systems; peptide based systems; wax coatings; compressed tablets using conventional binders and excipients; or partially fused implants. Specific examples include, but are not limited to, erosional systems in which the agent and / or pharmaceutical composition contained in a formulation within a matrix (for example, as described in U.S. Patent Nos. 4,452,775, 4,675,189, 5,736,152, 4,667,013, 4,748,034 and 5,239,660), or diffusional systems in which an active component controls the release rate (for example, as described in U.S. Patent Nos. 3,832,253, 3,854,480, 5,133,974 and 5,407,686). The formulation may be as, for example, microspheres, hydrogels, polymeric reservoirs, cholesterol matrices, or polymeric systems. The system may allow sustained or controlled release of the composition to occur, for example, through control of the diffusion or erosion / degradation rate of the formulation containing the agent and / or pharmaceutical composition. In addition, a pump-based hardware delivery system may be used for delivery.

[0243] As used herein the terms "subject" / " subject in need thereof', or "patient" / "patient in need thereof " are well-recognized in the art, and, are used interchangeably herein to refer to a mammal, including dog, cat, rat, mouse, monkey, cow, horse, goat, sheep, pig, camel, and, most preferably, a human. In some cases, the subject is a subject in need of treatment or a subject with a disease or disorder. However, in other aspects, the subject can be a normal subject. The term does not denote a particular age or sex. Thus, adult and newborn subjects, whether male or female, are intended to be covered. Preferably, the subject is a human, most preferably a human suffering from a neurodevelopmental, a neurological or a psychiatric disorder or disease or a human that might be at risk of suffering from a neurodevelopmental, a neurological or a psychiatric disorder or disease.

[0244] Also provided is a kit for performing a method according to the invention or for use in the treatment and / or prevention of a neurodevelopmental, a neurological or a psychiatric disorder or disease, said kit comprising

[0245] (a) one or more agents and / or pharmaceutical compositions of the invention, and optionally

[0246] (b) instructions for use.

[0247] The invention further provides a kit comprising:

[0248] (a) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, of the invention,

[0249] (b) a nucleic acid of the invention,

[0250] (c) a vector of the invention, (d) a pharmaceutical composition of the invention, or

[0251] (e) a composition of the invention, and optionally instructions for use.

[0252] In one aspect, the invention provides a kit comprising, or consisting of:

[0253] (a) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, of the invention,

[0254] (b) a nucleic acid of the invention,

[0255] (c) a vector of the invention,

[0256] (d) a pharmaceutical composition of the invention, or

[0257] (e) a composition of the invention, and optionally instructions for use.

[0258] In one aspect, the invention provides a kit comprising, or consisting of:

[0259] (a) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, of the invention,

[0260] (b) a nucleic acid of the invention,

[0261] (c) a vector of the invention,

[0262] (d) a pharmaceutical composition of the invention, and

[0263] (e) a composition of the invention, and optionally instructions for use.

[0264] In one aspect, the invention provides a kit comprising, or consisting of:

[0265] (a) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, SEQ ID NO. 3 or SEQ ID NO. 4 or a conservative variant thereof, of the invention,

[0266] (b) a nucleic acid of the invention, (c) a vector of the invention,

[0267] (d) a pharmaceutical composition of the invention, and / or

[0268] (e) a composition of the invention, and optionally instructions for use.

[0269] As used herein, a “kit” refers to an assemblage of one, two or more components packaged together or separately, which are intended for combined or sequential administration to a subject for the purpose of preventing, treating, alleviating, or managing a neurodevelopmental, a neurological or a psychiatric disorder or disease related to the hippocampus. The kit may comprise the following components:

[0270] (i) a C-terminal fragment of the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 2, or conservative variant thereof;

[0271] (ii) a nucleic acid encoding said C-terminal fragment; and

[0272] (iii) a vector comprising said nucleic acid, optionally within a delivery system (e.g., a viral vector or lipid nanoparticle).

[0273] The components of the kit of the invention may be formulated in the same or in separate pharmaceutical compositions and may be provided in unit dosage or multi-dose form, optionally together with one or more pharmaceutically acceptable carriers, diluents, or excipients.

[0274] The kit of the invention further comprises instructions for use, which describe the intended therapeutic indication(s), dosage regimens, route(s) of administration, order and timing of administration (e.g., single-step or multi-step), and any necessary reconstitution, mixing, or handling procedures.

[0275] The kit of the invention is intended for use in preventing, treating, alleviating, or managing a neurodevelopmental, a neurological or a psychiatric disorder or disease related to the hippocampus, and is particularly suitable for applications involving delivery to the central nervous system (CNS), including across or bypassing the blood-brain barrier (BBB). Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. It is to be understood that the invention includes all such variations and modifications without departing from the spirit or essential characteristics thereof. The invention also includes all of the steps, features, compositions and compounds referred to or indicated in this specification, individually or collectively, and any and all combinations or any two or more of said steps or features. The present disclosure is therefore to be considered as in all aspects illustrated and not restrictive, the scope of the invention being indicated by the appended Claims, and all changes which come within the meaning and range of equivalency are intended to be embraced therein. Various references are cited throughout this Specification, each of which is incorporated herein by reference in its entirety. The foregoing description will be more fully understood with reference to the following Examples. These examples are non-limiting and are merely representative of various aspects of the disclosure.

[0276] EXAMPLES

[0277] Materials and Methods:

[0278] Animals

[0279] Experimental protocols were approved by the Cantonal Veterinary Authorities (Vaud, Switzerland) and carried out in accordance with the European Communities Council Directive of 24 November 1986 (86 / 609EEC). All mice were adult male of 8 weeks-old at the beginning of the experiment, unless indicated. They were housed in a 12h light / dark cycle with free access to food and water and controlled temperature (23°C +- 1°C) conditions. C57B1 / 6J mice were purchased from Janvier (le Genest Saint Isle, France) or Charles River laboratories (Wilmington, MA, USA).

[0280] Cell culture aNSPC

[0281] Mouse aNSPC were isolated from the dentate gyrus of adult Fisher 344 rats and cultured in medium DMEM / F12 + Glutamax (Gibco / Life Technologies 31331-028) supplemented with 1% ofN2 Supplement lOOx (Gibco / Life Technologies 17502-048), Penicillin-Streptomycin lOOx (PS, 50 Ul / ml) (Gibco / Life Technologies 15140-122) and FGF-2 (20ng / ml) (PreProtech AF- 100-18B) as previously described (Ray J and Gage FH. ’’Differential properties of adult rat and mouse brain-derived neural stem cells”. Molecular and Cellular Neuroscience 2006 Mar 31(3). 560-73)). Mouse aNPCs were isolated from the dentate gyrus of adult C57B16 / J mice and cultured in medium DMEM / F12 supplemented with 1% of N2 Supplement lOOx, PS lOOx (50 Ul / ml), FGF-2 (20ng / ml) and EGF (20ng / ml) (PreProtech AF-100-15). ANSPCs were cultured on 10 cm dishes coated with Poly-Omithine (10 mg / ml) (Sigma- Aldrich P3655), Poly-D-lysine hydrobromide at O.lmg / ml (Sigma-Aldrich P6407) and Laminin at 20pg / ml (Gibco / Life Technologies 23017-015) for expansion and in 24-wells plates for experiments, with the same coating.

[0282] Astrocytes

[0283] Astrocytes were prepared from postnatal day 1-3 mice (WT or dnSNARE mice) as previously described Sultan et al. “Synaptic integration of adult-bom hippocampal neurons is locally controlled by astrocytes”. Neuron 2015 Dec 2. 957-952. Briefly, mice were decapitated, and brains were rapidly collected. Meninges were removed, and the hippocampi and cortices were dissected. Tissues were mechanically triturated for homogenization and seeded onto 25 cm2flasks in DMEM supplemented with Glutamax (Gibco / Life Technologies 10569-010), 10% of horse serum (Gibco / Life Technologies 16050-122) and PSF lOOx (50 Ul / ml) (Gibco / Life Technologies 15140-122). Cells were grown for one week in a humidified 5% CO2 incubator at 37°C. Every 2 days during the week, flasks were shaken to separate microglia from astrocytes and were washed with HBSS (Gibco / Life Technologies 14025-092). The enrichment of astrocytes in cultures was assessed by immunostaining. 98% of the cells expressed GFAP and none of the cells expressed the neuronal markers NeuN, DCX, TUJ1 or Map2 (data not shown), showing that this process efficiently removes neurons.

[0284] Astrocyte conditioned medium (ACM) or astrocyte conditioned solution (ACS)

[0285] For in vitro experiments, ACM was prepared from confluent WT or dnSNARE astrocyte cultures in 25 cm2flasks. Medium was removed and the cultures were washed twice with HBSS (Gibco / Life Technologies 14025-092) and replaced by aNSPC medium for 24h before being applied on aNSPC. For in vivo injections, ACS was prepared from confluent WT astrocyte cultures in 25 cm2flasks. Medium was removed and the cultures were washed twice with HBSS (Gibco / Life Technologies 14025-092) to eliminate residual serum and replaced by 2 ml of Tyrode’s solution (HEPES 10 mM, NaCl 145 mM, KC1 5.4 mM, CaCl21.8 mM, MgCl20.8 mM, Glucose 10 mM, ddH2O qsp) for 24h. ACS was then collected and filtered with a 0.22 urn filter (Millipore) to eliminate cellular debris. ACS was prepared fresh every day. For LC / MS analyses, astrocytes were grown in flasks for at least 10 days. Before the experiment, astrocyte cultures were washed twice with HBSS (Gibco / Life Technologies 14025-092) and the astrocyte medium was exchanged with 2 ml of Tyrode’s solution per flask and astrocytes cultures were incubated at 37°C for 24h. The medium was then collected and filtered with a 3 kDa filter (Amicon Ultra-4 centrifugal Filter 3 kDa MWCO, Merck UFC8003243). Five distinct preparations of ACS <3 kDa were prepared from five astrocytes cultures and were then sent to the Protein Analysis Facility (Genopode (UNIL) - CH-1015 Lausanne) for Mass Spectrometry analysis.

[0286] Size exclusion filtration and Proteinase K treatment

[0287] ACS was prepared from astrocyte cultures with aNSPC medium and filtered with a 3 kDa filter (Amicon Ultra-4 centrifugal Filter 3 kDa MWCO, Merck UFC8003243 to obtain a < 3 kDa and a > 3 kDa fraction. To avoid depleting the medium from necessary molecules, these fractions were then supplemented with their opposite fraction of non-conditioned medium. ACS fractions were treated with Proteinase K (100 ug / ml) (Sigma- Aldrich P4850) during 3h at 37°C.

[0288] Mass Spectrometry

[0289] Proteomics analyses

[0290] Five distinct preparations of ACS <3kDa were prepared from distinct astrocytes cultures. All samples were filtered using Amicon 0.5 ml Ultracel-IOK filters (Millipore), and the eluates were acidified with TFA 20%, desalted on a StageTip C18 lOpl (Thermo Scientific), speedvacuum dried and redissolved in loading buffer. The prepared sample was injected into a Fusion Tribrid Orbitrap mass spectrometer using a 65 -minute gradient with high-resolution accurate-mass MS / MS. The raw files were analyzed using Mascot and PEAKS software for peptide identification through both de novo and database search, with no enzyme specified in the search parameters

[0291] For immunoprecipitation experiments, samples were loaded on a 12 % mini polyacrylamide gel, migrated about 2.5 cm and stained by Coomassie. Gel lanes between 10-300 kDa were excised into 5 pieces and digested with sequencing-grade trypsin as described. Extracted tryptic peptides were dried and resuspended in 0.05% trifluoroacetic acid, 2% (v / v) acetonitrile as loading buffer for Mass Spectrometry analyses.

[0292] Liquid Chromatography-Mass Spectrometry analyses

[0293] Data-dependent LC-MS / MS analyses of samples were carried out either on a Fusion Tribrid Orbitrap instrument (astrocyte, immunoprecipitation and microdialysate samples) or on a QExactive Plus mass spectrometer (immunoprecipitation samples), interfaced through a nanoelectrospray ion source to an Ultimate 3000 RSLCnano HPLC system (Thermo Fisher Scientific). Peptides were loaded onto a trapping microcolumn Acclaim PepMaplOO C18 (20 mm x 100 pm ID, 5 pm, Dionex) before separation on a reversed-phase custom packed 45 cm Cl 8 column (75 pm ID, 100 A, Reprosil Pur 1.9 um particles, Dr. Maisch, Germany) with a 4- 76 % acetonitrile gradient in 0.1% formic acid (total time: 65 min).

[0294] In Fusion instrument full MS survey scans were performed at 120'000 resolution. A data- dependent acquisition method controlled by Xcalibur software (Thermo Fisher Scientific) was used that optimized the number of precursors selected (“top speed”) of charge 2+ to 5+ while maintaining a fixed scan cycle time. Peptides were fragmented by higher energy collision dissociation (HCD) with a normalized energy of 32%. The precursor isolation window used was 1.6 Th, and the MS2 scans were done either at low resolution in the ion trap (immunoprecipitation and microdialysate samples) or in the orbitrap at 15’000 resolutions (astrocyte samples). The m / z of fragmented precursors was then dynamically excluded from selection during 60 s.

[0295] For microdialysate analyses, PEA116 peptide standard was also injected on the MS instrument, and additional targeted MS and MS / MS scans of m / z 661.865, corresponding to PEA116 peptide mass, were included in the LC-MS / MS method.

[0296] In QExactive instrument full MS survey scans were performed at 70,000 resolution. In data- dependent acquisition controlled by Xcalibur software, the 10 most intense multiply charged precursor ions detected in the full MS survey scan were selected for higher energy collision- induced dissociation (HCD, normalized collision energy NCE=27 %) and analysis in the orbitrap at 17’500 resolution. The window for precursor isolation was of 1.5 m / z units around the precursor and selected fragments were excluded for 60s from further analysis.

[0297] Data processing

[0298] MS data of immunoprecipitation samples were analyzed using Mascot 2.7 (Matrix Science, London, UK) set up to search the rat (Rattus norvegicus) reference proteome based on the UniProt database (www.uniprot.org, version of November 5th, 2019, containing 29’958 sequences) and a custom contaminant database containing the most usual environmental contaminants and enzymes used for digestion (keratins, trypsin, etc.). Trypsin (cleavage at K,R) was used as the enzyme definition, allowing 2 missed cleavages. Carbamidomethylation of cysteine was specified in Mascot as a fixed modification. Protein N-terminal acetylation and methionine oxidation were specified as variable modifications. Mascot was searched with a parent ion tolerance of 10 ppm and a fragment ion mass tolerance of 0.02 (QExactive data) or 0.5 Da (Fusion data). Scaffold 4 (Proteome Software Inc., Portland, OR) was used to validate MS / MS based peptide and protein identifications.

[0299] MS data of astrocyte samples were analyzed using Mascot 2.6 ((Matrix Science, London, UK) set up to search the SwissProt database restricted to Mus musculus taxonomy (www.uniprot.org, version of November 2016, containing 16’846 mouse sequences), and a custom contaminant database containing the most usual environmental contaminants and enzymes used for digestion (keratins, trypsin, etc.). Nonspecific cleavage was used as the enzyme definition, and methionine oxidation was specified as variable modification. Mascot was searched with a parent ion tolerance of 10 ppm and a fragment ion mass tolerance of 0.02 Da. Scaffold 4 (Proteome Software Inc., Portland, OR) was used to validate MS / MS based peptide and protein identifications.

[0300] MS data of microdialysate samples were analyzed using Mascot 2.8 ((Matrix Science, London, UK) set up to search the SwissProt database restricted to Mus musculus taxonomy (www.uniprot.org, version of April 2021, containing 17’097 mouse sequences), and a custom contaminant database containing the most usual environmental contaminants and enzymes used for digestion (keratins, trypsin, etc.). Nonspecific cleavage was used as the enzyme definition. Protein N-terminal acetylation and methionine oxidation were specified as variable modifications. Mascot was searched with a parent ion tolerance of 10 ppm and a fragment ion mass tolerance of 0.5 Da. Scaffold 5 (Proteome Software Inc., Portland, OR) was used to validate MS / MS based peptide and protein identifications.

[0301] In Scaffold validation, peptide identifications were accepted if they could be established at greater than 90.0% probability by the Peptide Prophet or the Scaffold Local FDR algorithm. Protein identifications were accepted if they could be established at greater than 95.0% probability and contained at least 1 identified peptide. Protein probabilities were assigned by the Protein Prophet algorithm (Nesvizhskii et al. “A statistical model for identifying proteins by tandem mass spectroscopy”. Analytical Chemistry 2003 Sept(l):4646-58). Proteins that contained similar peptides and could not be differentiated based on MS / MS analysis alone were grouped to satisfy the principles of parsimony. Proteins sharing significant peptide evidence were grouped into clusters.

[0302] Peptide synthesis

[0303] Peptides Pl, P2, P3, P4, PEA116 and PEA116-HA were synthesized by the Peptide & Tetramer Core facility (Epalinges (UNIL), Switzerland). Peptides were produced by Solid Phase Peptides Synthesis (SPPS) using fmoc / tBu strategy. Peptides were assembled using CSBio 136M instrument, purified by reverse-phase HPLC and analysed by UHPLC-MS (Agilent Technologies). Identity was confirmed by Mass Spectrometry (+ / - 1 da of calculated theoretical peptide mass) and the purity of all peptides was above 95%, based on Abs at 215 nm. Peptides were kept lyophilized at -20°C or below and resuspended in water prior to use. scRNAseq analyses

[0304] Expression of PEA15 in single-cell RNAseq data from Franjic et al. “Transcriptomic taxonomy and neurogenic trajectories of adult human, macaque and pig hippocampal and entorhinal cells”. Neuron 2022 Feb: 452-469 and Hochgemer et al “Conserved properties of dentate gyrus neurogenesis across postnatal development revealed by single-cell RNA sequencing”. Nature Neuroscience 2018 Feb. 290-299, as analyzed using Seurat v4.1.1. Single-cell sequencing data and cell-type annotations of mouse and human DG cells were obtained from the GEO repository (GSE95315 and GSE186538). Basic filtering of cells based on the fraction of mitochondrial reads (< 6%) was performed using Seurat v4.1.1. Cells from the human dataset were furthermore filtered based on the number of available features (nFeature_RNA > 600 & nFeature_RNA < 12000). Normalization and scaling of the sequencing data was performed using the default settings of Seurat’s ‘NormalizeData’ and ‘ScaleData’ functions. Principal components were calculated by ‘RunPCA’. Dimensionality reduction was performed by ‘RunUMAP’, using the first thirty principal components as input.

[0305] In vitro experiments

[0306] Cell culture and immunostaining

[0307] ANSPC were plated at in a 24-well-plate coated at a density of 60 000 cells per well. For treatment with ACS, medium was removed and 500 pl of ACS was added on aNSPC for 24h. For treatment with the PEA116 or PEA116-HA peptide, the peptides were solubilized in ddFEO and aNSPC were treated with PEA116 at 50 uM in 500 pl of aNSPC medium or with PEA116-HA at 100 pM in 500 pl of aNSPC medium for 24h. DdFEO was used as control. To assess cell proliferation, the medium was supplemented with 5 pM BrdU for 30 min and washed twice with pre-heated fresh medium followed by Ih incubation. Cells were fixed with 4% paraformaldehyde for 30 minutes and rinsed with PBS 0. IM or fixed with ice-cold MeOH 100% for 15 minutes and rinsed with PBS 0. IM before p-ERKl / 2 and ERK1 / 2 immunostaining. Immunostainings against p-ERK, ERK, RFP, and Caspase-3 were processed as follows : after 3 washes with PBS 0.1M, cells were saturated with blocking solution (PBS 0.1M, decomplemented Horse serum 10%, Triton lOOx 0.3%) during Ih. Plates were incubated with primary antibodies rabbit anti-ERKl / 2 (1 / 500, Cell Signaling 4695), rabbit anti-p-ERKl / 2 (1:500, Cell Signaling 9101S), rabbit anti-RFP (1:500, Rockland 600-401-379), mouse anti- RFP (1:500, ThermoScientific MA5-15257), rabbit anti-HA (1:500, Cell Signaling C29F4) or rabbit anti -Caspase-3 (1:500, Cell Signaling 9579) overnight at 4°C. Fluorescence was achieved by adding secondary antibodies goat anti-mouse Alexa Fluor 488 (1:300, Invitrogen Al 1029), goat anti-rabbit AlexaFluor488 (1:300, Invitrogen Al 1034), goat anti-rabbit AlexaFluor594 (1:300, Life Technologies Al 1037) or goat anti-mouse AlexaFluor594 (1:300, Invitrogen Al 1032) during Ih at room temperature. Finally, cells were incubated with DAPI (1 : 1000) for 10 minutes to reveal their nuclei. Immunostaining against BrdU was processed as follows: after 3 washes with PBS 0.1M, aNSPC were treated with HC1 2N for 15 minutes at 37°C then rinsed with borate buffer 0.1M for 15 minutes. After 3 washes with PBS 0.1M, cells were saturated with blocking solution (PBS 0.1M, decomplemented Horse serum 10%, Triton lOOx 0.3%) during Ih. Plates were incubated with primary antibodies mouse anti-BrdU (1:250, BdBiosciences B44 / 347580) overnight at 4°C. Fluorescence was achieved by adding secondary antibodies goat anti-mouse Alexa Fluor 488 (1:300, Invitrogen A11029) during Ih at room temperature. Finally, cells were incubated with DAPI (1:1000) for 10 minutes to reveal their nuclei.

[0308] Image acquisition and analysis

[0309] Images were acquired using an Eclipse Ti2 inverted microscope (Nikon). The number of BrdU- labeled aNSPC was counted in one randomly selected large field (tiles 4x4) in each well of the plate with Imaris software. At least 6 wells were analyzed by treatment. The number of BrdU- labeled aNSPC was compared with the total number of aNSPC in each selected field to obtain a proliferation ratio.

[0310] ERK phosphorylation

[0311] The level of phosphorylated ERK1 / 2 in HEK-293 cell cultures was determined using the “ERK Phosphorylation ELISA Assay Kit” (ABIN1019677). Cells were treated with PEA116 (100 pM) for 10, 20, 30, 60 and 90 minutes prior to fixation and analysis. The ERK1 / 2 inhibitor U0126 (20 pM, SigmaAldrich, 662005) was used as and negative control.

[0312] In vivo experiments

[0313] Injections

[0314] Mice were injected intraperitoneally with 200 pl of ACS pre-warmed at 37°C, prepared from a different dish of astrocytes each day for 8 days. For the PEA116 peptide injection, mice were injected intraperitoneally with PEA116 dissolved in Tyrode’s solution at a concentration of 5 mg / kg each day for 8 days in all experiment except for the study of quiescence in vivo, where mice were injected 3 times over 48h. BrdU was dissolved in 0.9% NaCl and injected at a concentration of 100 mg / kg 3 times each 2h (Sigma- Aldrich, Buchs, Switzerland). CldU compound was dissolved in 0.9% NaCl and injected at a concentration of 42.5 mg / kg either 3 times each 9h for the experiment about quiescence exit in vivo, or 3 times each 2h to assess net neurogenesis. IdU was dissolved in a solution containing 20% NaOH 0.2M + 80% NaCl 0.9% at a concentration of 57.5 mg / kg and was injected 3 times each 9h. TMZ was dissolved inNaCl 0.9% and injected at a concentration of 25 mg / kg (Sigma-Aldrich, T2577).

[0315] Tissue collection and preparation

[0316] Mice received a lethal dose of pentobarbital (10 mL / kg, Sigma, Switzerland) via intraperitoneal injection. Following this, they were perfused with 0.9% NaCl for 3 minutes, followed by perfusion with 4% paraformaldehyde (PF A) for 3 minutes (Sigma- Aldrich, USA) dissolved in 0.1 M Phosphate Saline Buffer (PBS, pH 7.4). Their brains were dissected, fixed overnight at 4°C in PFA 4%, and then incubated for 24h in a 30% sucrose solution at 4°C (Sigma-Aldrich, USA). The brains were rapidly frozen using isopentane at -40°C. Forty pm thick coronal sections were prepared using a cryostat (Leica MC 3050S) and were preserved in cryoprotectant (30% ethylene glycol + 25% glycerin in 0.1 M PBS) at -20°C.

[0317] Immunochemistry and antibodies

[0318] Immunochemistry was performed on every 6th section of the dentate gyrus. Sections were washed 3 times in PBS 0.1 M and permeabilized / blocked using PBS 0.1 M containing 0.3% Triton-X 100 and 10% Horse serum. BrdU immunohistochemistry was preceded by DNA denaturation by incubation in formic acid 50% formamide / 50% 2X SSC buffer (2X SSC is 0.3 M NaCl and 0.03 M sodium citrate, pH 7.0) at 60°C for 2 h, rinsed twice in 2X SSC buffer, incubated in HC12M for 30 min at 37°C and rinsed in 0.1 M borate buffer pH 8.5 for 15 minutes and 6 times in PBS 0.1M for 10 minutes each. Then, sections were incubated overnight at 4°C with one of the following primary antibodies: rat monoclonal mouse anti-BrdU / IdU (1:250 or 1:500, BdBiosciences B44 / 347580), rat monoclonal anti-BrdU / CldU (1:500, Abeam ab6326), rat anti-Tbr2 (1:250, ebioscience 14-4875-82), mouse anti-NeuN (1:500, Chemicon MAB377), rabbit anti-NeuN (1:1000, Abeam EPR12763), rabbit anti-GFAP (1:500, Dako Z0334), rabbit anti-Sox2 (1:500, Millipore AB5603), mouse anti-DCX (1:400, Santa Cruz sc8066), rabbit anti-DCX (1:500, Abeam abl8723), rabbit anti-Caspase-3 (1:500, Cell Signaling 9661S). Sections were then incubated for Ih 15 at room temperature with the corresponding fluorescent secondary antibodies: goat anti-mouse AlexaFluor594 (1:300, Invitrogen Al 1032), goat antirat AlexaFluor488 (1:300, Invitrogen Al 1006), donkey anti-mouse AlexaFluor647 (1:300, Invitrogen A31571), donkey anti-rabbit AlexaFluor647 (1:300, Invitrogen A31573), goat antirat AlexaFluor594 (1:300, Invitrogen Al 1007), goat anti-rabbit AlexaFluor488 (1:300, Invitrogen Al 1034). Finally, sections were incubated in DAPI (1 / 1000) to reveal their nuclei and washed 3 times in PBS 0. IM before being mounted on slides. Imaging

[0319] The number of BrdU-positive cells was counted in the subgranular region of the dentate gyrus. This was done using an epifluorescence microscope (Zeiss AxioSkop2Plus) equipped with a camera (Zeiss AxioCamMRm) and a 20x objective. All cells were quantified throughout the entire thickness of the section. Using ImageJ software, the contour of the dentate gyrus of each section was traced to calculate the volume of the DG and determine the ratio of BrdU-positive cells in the whole volume of the dentate gyrus. Sections marked with GFAP, Tbr2, Sox2, DCX, NeuN or Caspase-3 were imaged using a laser scanning confocal microscope (Zeiss LSM780 GaAsp) equipped with a 20x objective (numerical aperture 1.0) and an automated optical configuration optimized for sequential visualization of each fluorescence channel or using a Nikon NI-E spinning disk with 20x objective. For each tissue volume sampled, adjacent image planes through the z-axis were collected throughout the entire thickness of the tissue. Images were analyzed with ZenBlue software (Zeiss).

[0320] Histological analysis of inflammation

[0321] Immunochemistry was performed on every 6th section of the dentate gyrus. Sections were washed 3 times in PBS 0.1 M and blocking of non-specific binding was achieved by incubating in PBS 0.1 M containing 0.3% Triton-X 100 and 10% Horse serum. Then, sections were incubated over night at 4°C with the following primary antibodies: rat anti-CD68 (1:1000, Abeam 53444), rouse anti-GFAP (1:500, Millipore MAB360), rabbit anti-Ibal (1:500, Wako 019-19741). Then, sections were incubated for lhl5 at room temperature with the following fluorescent secondary antibodies: goat anti-rat Alexa Fluor 488 (1:300, Life Technologies A11006), goat anti- rabbit Alexa Fluor594 (1:300, Life Technologies A11037), donkey antimouse Alexa Fluor 647 (1:300, Invitrogen A31571). Finally, sections were incubated in DAPI (1 / 1000) to reveal their nuclei and washed 3 times in PBS 0. IM before being mounted on slides. Images acquired with the Nikon Spinning Disk microscope (details provided) were analyzed using the NIS-Elements software. The General Analysis (GA) tool within NIS-Elements facilitated automated morphometric and density analysis. Masks were created based on Ibal staining for microglia or GFAP coverage for astrocytes. Regions of Interest (ROIs) were delineated according to anatomical landmarks to extract information about the total dentate gyrus area. For detailed microglial morphometry, multipoint images were processed using IMARIS 5.1 (Oxford Instruments) for three-dimensional reconstructions. The filament tool in IMARIS enabled reconstruction of microglial fine processes, providing information on ramification.

[0322] Chronic and acute restraint stress

[0323] The 21 days CRS was performed as follows: Mice were placed headfirst into 50 ml Falcon tubes (11.5 cm in length, 3 cm in diameter) with perforations at the bottom for ventilation, and tissue was placed at the end to adjust the constraint to the size of the mouse, allowing the tail to extend out. This restraint lasted for 2h daily for 21 consecutive days. For the ARS, we used the same protocol as for the CRS, with a restraint of 6 hours. After this, mice were returned to their home cages for 20 minutes before undergoing an open-field test to evaluate anxiety-like behavior.

[0324] Behavioral tests

[0325] Open-field test (OFT)

[0326] The OFT was conducted following previously established protocols. The setup comprised a square Plexiglas enclosure measuring 40 x 40 x 40 cm, illuminated with dimmed light (25 lux). Mice were placed facing the wall of the arena and given 10 minutes to freely explore the arena. The arena was divided into zones including a virtual center zone (15 x 15 cm) and a thigmotaxis zone (within 10 cm of each wall), which were analyzed to assess anxiety-like behavior. A video tracking system (Anymaze software) recorded the movement of each mouse, total distance travelled, and time spent in each zone. To prevent olfactory cues, the OF was cleaned after each trial.

[0327] Elevated plus maze test (EPM)

[0328] The apparatus was constructed from black PVC with a white floor and consisted of a central platform (5 x 5 cm) elevated 65 cm from the ground, featuring two open arms (30 x 5 cm) and two closed arms (30 x 5 x 14 cm) arranged in opposing pairs. Light intensity was maintained at 15 lux in the open arms and 4 lux in the closed arms. Animals were placed at the end of the closed arms facing the wall and allowed to freely explore the apparatus for 5 minutes. Anymaze software was used to follow the movements of the mice and to measure the time spent in each arm and at the risk zones (edges of the open arms). To prevent olfactory cues, the EPM was cleaned after each trial.

[0329] Light Dark Test (LDT) A Plexiglas box measuring 60 x 40 x 21 cm was utilized, divided into a dark compartment (20 x 40 x 21 cm) and a light compartment (40 x 40 x 21 cm) illuminated at 400 lux. The compartments were separated by an open door (5 x 5 cm) positioned centrally at floor level. Each mouse was introduced into the light chamber facing the door and allowed to explore freely for 6 minutes. Anymaze software was used to follow the movements of the mice and to measure anxiety-like behavior by analyzing the time spent in each zone. To prevent olfactory cues, the chambers were cleaned after each trial.

[0330] Marble Burying test (MB)

[0331] The MB test was conducted following previously established protocols (2493296270). A cage measuring 40 x 25 x 20 cm was filled to a depth of approximately 5 cm with husk bedding material, which was evenly spread across the cage's surface. Twenty plain dark glass marbles, each with a diameter of 1.4 cm, were then arranged in a 4 * 5 grid on top of the bedding. Each mouse was introduced into the cage and allowed to explore it for 20 minutes under 300 lux lighting conditions. Following the test, the mice were removed from the cage, and the number of marbles buried with bedding up to 2 / 3 of their depth was counted. Between each trial, the marbles were removed, and the bedding was stirred, spread, and compacted before the marbles were replaced.

[0332] Anxiety scores

[0333] The anxiety score was computed following the methodology outlined in previous studies (22987479, 25339861 (Grieco F et al. "Natural variations of adolescent neurogenesis and anxiety predict the hierarchical status of adult inbred mice." EMBO Rep. 2025 Mar;26(6): 1440-1456.)), involving the averaging of standardized scores from various anxiety- related behavioral tests. Standardization was achieved by subtracting the minimum value of the entire population from each animal's value and then dividing the result by the difference between the maximum and minimum values of the entire population: (x - min value) / (max value - min value). This process yielded scores between 0 and 1, with higher scores indicating greater levels of anxiety. The score was derived from factors such as the time spent in the dark chamber of the LDT and the time spent in the closed arm of the EPM. In OFT, it included the time spent in thigmotaxis and in the center of the arena.

[0334] Statistics All statistical tests were performed with GraphPad Prism (GraphPad 9 software, San Diego, CA, USA) or RStudio (RStudio Team (2023). RStudio: Integrated Development for R. RStudio, PBC, Boston, MA, Version 1.2.5033) using a critical probability of p < 0.05. Statistical analyses performed for each experiment are summarized in each figure legend with the chosen statistical test, sample size ‘n’ and p values. All values are given as mean ± S.E.M. For experiments with two groups, a Shapiro-Wilk test was performed before all tests to assess normality followed by an unpaired Student t-test or a non-parametric Mann-Whitney test according to the results of the normality test. In an experiment with more than two groups, a Shapiro-Wilk test was performed to assess normality and a Bartlett test of heteroscedasticity were done before all tests. One-Way ANOVA or Kruskal -Wallis test was performed according to the results of the pre-tests. A post-hoc Tukey’s or Dunn’s test was performed for multiple comparisons. In Figure 4, for OLT (Figure 41, 4J), NOR (Figure 4K), OFT (Figure 4N, 40, 4R, 4S) and the anxiety score combining EPM + LDT + MB (Figure 4W), the difference between groups was analyzed by an unpaired Student t-test and. The difference between each group and the theoretical mean for anxiety score set at 0.5 was assessed with a one sample t-test.

[0335] Results:

[0336] Figure 1 A shows a higher number of proliferating adult Hippocampal stem / progenitor cells in PEA116-treated mice compared to vehicle-treated mice. Moreover, in an anxiety mouse model, the treatment of mice with the C-terminal fragment PEA116 shows a reduction in the anxiety score compared to vehicle-treated mice. Notably, the effect of the C-terminal fragment PEA116 on the reduction of anxiety is inhibited (to a level comparable to the vehicle-treated mice) when mice are treated with TMZ concomitantly with PEA116 (Figure IB). Moreover, mice treated with the C-terminal fragment PEA116 show a higher number of newborn hippocampal neurons compared to the vehicle-treated mice and also compared to mice treated with TMZ concomitantly with PEA116 (Figure 1C). Taken together, these result show that the use of Temozolomide (TMZ), which inhibits neurogenesis in the hippocampus, suppresses the induction of neurogenesis produced by the PEA116 C-terminal fragment. Therefore, the use of the C-terminal fragment PEA116 in mice promotes neurogenesis in the hippocampus, thereby reducing the anxiety-like symptoms after chronic stress. Furthermore, the inventors have surprisingly found that the use of the C-terminal fragment PEA116 promoting neurogenesis in the hippocampus and reducing anxiety symptoms, represents an attractive therapeutic candidate for applications targeting disorder or disease related to the hippocampus selected from the group comprising a neurodevelopmental, a neurological or a psychiatric disorder or disease, or more specifically for treating or alleviating memory- and anxiety -related disorders or diseases (Braga RJ et al. " Anxiety comorbidity in schizophrenia". Psychiatry Res (2013) 210:1-7.

[0337] Goldstein-Piekarski AN et al. " A trans-diagnostic review of anxiety disorder comorbidity and the impact of multiple exclusion criteria on studying clinical outcomesin anxiety disorders ". Transl Psychiatry (2016) 6:e847.

[0338] Larners F et al. " Comorbidity patterns of anxiety and depressivedisorders in a large cohort study: the Netherlands Study of Depression and Anxiety (NESDA)" J Clin Psychiatry (2011) 72:341-8.

[0339] Pavlova B et al. " Prevalence of current anxiety disorders in people with bipolar disorder during euthymia: a 693 meta-analysis " Psychol Med (2017) 47:1107-1115.

[0340] Gu Y et al. " Optical controlling reveals time-dependent roles for adult-bom dentate granule cells." Nat Neurosci. 2012 Dec;15(12): 1700-6.

[0341] Moreno- Jimenez EP et al. " Adult hippocampal neurogenesis is abundant in neurologically healthy subjects and drops sharply in patients with Alzheimer's disease " Nat Med. 2019 Apr;25(4):554-560.

[0342] Choi SH et al. " Combined adult neurogenesis and BDNF mimic exercise effects on cognition in an Alzheimer's mouse model ").

[0343] The inventors have surprisingly discovered that a specific C-terminal fragment PEA116, derived from a naturally occurring full-length protein (PEA- 15), exhibits a significant and robust positive effect on neurogenesis. Importantly, the use of a shorter peptide fragment (PEA116) offers several advantages over the full-length protein (PEA- 15), including improved stability, reduced production costs, enhanced tissue penetration, and a lower risk of immunogenicity. These benefits make the peptide fragment (PEA116) an attractive therapeutic candidate for applications targeting disorder or disease related to the hippocampus selected from the group comprising a neurodevelopmental, a neurological or a psychiatric disorder or disease. The inventors surprisingly found that the C-terminal peptide fragment of the invention, rather than the full-length protein, offers significant advantages for CNS-targeted therapies, particularly when delivery across the blood-brain barrier (BBB) is required. Due to its smaller size, the peptide is more likely to cross the BBB via passive diffusion or transport-mediated mechanisms and can more effectively diffuse through brain tissue once inside the CNS.

[0344] Additionally, shorter peptides typically exhibit improved stability, lower immunogenicity, and reduced risk of off-target effects compared to full-length proteins. These characteristics make the C-terminal peptide fragment of the invention a more practical and efficient candidate for direct CNS administration. Moreover, the use of the C-terminal peptide fragment of the invention (PEA116) offers the advantage of having a more compact size if used in AAV delivery systems and allows for easier packaging within vectors that have limited carrying capacity, while also enabling inclusion of regulatory elements to control tissue-specific expression. Furthermore, shorter sequences are generally transcribed and translated more efficiently, with reduced risk of misfolding or post- translational complications. This results in more reliable in vivo expression and enhances the safety, scalability, and therapeutic potential of the peptide for CNS applications.

[0345] Sequences:

[0346] SEQ ID NO. 1 - human Astrocytic phosphoprotein PEA- 15

[0347] MAEYGTLLQDLTNNITLEDLEQLKSACKEDIPSEKSEEITTGSAWFSFLESHNKLDKD NLSYIEHIFEISRRPDLLTMVVDYRTRVLKISEEEELDTKLTRIPSAKKYKDIIRQPSEEE IIKLAPPPKKA

[0348] SEQ ID NO. 2 - C-terminal fragment of PEA-15 (fragment 116-127, named PEA116)

[0349] SEEEIIKLAPPP

[0350] SEQ ID NO. 3 - variant consensus sequence

[0351] (R / K)2-3-Xl-8-O-X-0 where X is any amino acid, and

[0352] G is a hydrophobic amino acid.

[0353] SEQ ID NO. 4 - PEA116 peptide conjugated to an HA tag

[0354] YPYDVPDYASG-SEEEIIKLAPPP

[0355] Table 1:

[0356] Table 2:

Claims

CLAIMS1. A pharmaceutical composition comprising a therapeutically effective amount of a C- terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, and a pharmaceutically acceptable carrier and / or diluent for use in the treatment and / or prevention of a disorder or disease related to the hippocampus selected from the group comprising a neurodevelopmental, a neurological or a psychiatric disorder or disease.

2. The pharmaceutical composition of claim 1, wherein the conservative variant, comprises, or consists of, one or more additions, substitutions and / or deletions within amino acid sequence SEQ ID NO. 2.

3. The pharmaceutical composition of claim 1 or 2, wherein the conservative variant of SEQ ID NO. 2 comprises, or consists of, one or two mutations within SEQ ID NO. 2.

4. The pharmaceutical composition of any one of the preceding claims, wherein the composition is in a form for delivery across the blood brain barrier or for administration by direct injection into the central nervous system.

5. The pharmaceutical composition of any one of the preceding claims, wherein the SEQ ID NO. 2, or conservative variant thereof, is chemically modified for enhanced transmembrane transport.

6. The pharmaceutical composition of any one of the preceding claims, wherein the SEQ ID NO. 2, or the conservative variant thereof, is conjugated to a moiety capable of absorptive- mediated or receptor-mediated transcytosis through the subject's blood brain barrier.

7. The pharmaceutical composition of claim 6, wherein the moiety capable of absorptive- mediated or receptor-mediated transcytosis through the subject's blood brain barrier is a peptide, preferably a Cell-Penetrating peptide (CPP) selected from the group comprising HIV- TAT, Penetratin, SynBl / SynB3, polyarginine (e.g. R8, R9), polylysine (e.g., K8, K9), Transportan (chimeric galanin-mastoparan peptide), MAP, Pep-1, MPG (based on HIV gp41 and SV40 NLS), Pep-7 (yeast signal sequence), C105Y, pVEC (from cadherin domain), Antp (Antennapedia fragment), VP22 (derived from Herpes Simplex Virus VP22 protein), Ku70- derived CPPs (e.g., VPTLK), Angiopep-2, SynB peptides (from protegrin analogs), and Bac7 fragments (proline-arginine-rich antimicrobial peptides) or a combination thereof.

8. The pharmaceutical composition of claim 6, wherein the moiety capable of absorptive- mediated transcytosis is a peptide selected from the group comprising one or more of a p97 (mel anotransferrin) polypeptide, a Receptor Associated Protein (RAP), an aprotinin peptide or an analog thereof, a protein transduction domain (PTD), a human low-density lipoprotein receptor (hLDLR) binding peptide or an analog thereof, an antibody or natural ligand that binds to a BBB-associated receptor, and glutathione (GSH).

9. The pharmaceutical composition of claim 6, wherein the moiety capable of receptor- mediated transcytosis is a receptor selected from the group comprising one or more of the insulin receptor, the transferrin receptor, the leptin receptor, lipoprotein receptors such as the lipoprotein receptor-related protein (LRP-1) receptor, insulin-like growth factor (IGF) receptors such as IGF1R and IGF2R, the low-density lipoprotein receptor (e.g. Low-Density Lipoprotein Receptor-Related Protein 1), the diptheria toxin receptor, LRP1 receptor and TMEM 30A (Flippase).

10. The pharmaceutical composition of claim 6, wherein the moiety capable of receptor- mediated transcytosis is a ligand selected from the group comprising one or more of insulin, transferrin and transferrin fragments, lactoferrin and lactoferrin fragments, apolipoprotein A (Apo A), apolipoprotein B (Apo B), apolipoprotein E (Apo E), Angiopep-2 and diptheria toxin (including non-toxic mutants thereof such as CRM45 and CRM197).

11. The pharmaceutical composition of claim 6, wherein the moiety capable of absorptive- mediated transcytosis is selected from the group comprising one or more of a palmitoyl or myristoyl group, cholesterol, polyethylene glycol (PEG), Glucose / mannose, and D-glutamate.

12. The pharmaceutical composition of claim 6, wherein the moiety capable of absorptive- mediated transcytosis is selected from the group comprising a nanoparticle, a lipid-based nanoparticle or a carrier attachment moiety.

13. The pharmaceutical composition of any one of the preceding claims, wherein said composition is co-administered with an anti-glucocorticoid drug in a sufficient amount to increase permeability of the subject's blood brain barrier.

14. The pharmaceutical composition of any one of the preceding claims, wherein the neurodevelopmental, neurological or psychiatric disorder or disease related to the hippocampus is selected from the group comprising schizophrenia, for example of the paranoid, disorganized, catatonic, undifferentiated, or residual type; schizophreniform disorder; schizoaffective disorder, for example of the delusional type or the depressive type, cognitive impairment associated with schizophrenia (CIAS), bipolar disorder, ADHD, anxiety, anxiety- related disorders, depression, cognitive dysfunction, borderline personality disorder (BPD), depression or cognitive impairment induced by cytokines or chemotherapies administration, inflammation-related cognitive impairment or mood impairment, Alzheimer’s disease, Parkinson's disease, post-traumatic stress disorder, frontal temporal dementia, dementia, memory-related disorders, chronic pain, sleep and circadian disorders and sleep disruption, Cushing's Syndrome, Addison's Disease, Congenital Adrenal Hyperplasia (CAH), Secondary Adrenal Insufficiency, Hypothalamic-Pituitary-Adrenal (HP A) Axis Dysfunction. Ectopic ACTH Syndrome, Glucocorticoid Resistance Syndrome, Adrenal Carcinoma, or a combination of one or more thereof.

15. A C-terminal fragment of the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof.

16. The C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, of claim 15 wherein the PEA-15 protein, or variant thereof is(a) chemically modified for enhanced transmembrane transport, and / or(b) conjugated to a moiety capable of absorptive-mediated or receptor-mediated transcytosis through a subject's blood brain barrier.

17. A nucleic acid encoding the C-terminal fragment of the Astrocytic phosphoprotein (PEA-15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, of claim 15 or 16 (a), or a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, conjugated to a moiety capable of absorptive-mediated or receptor-mediated transcytosis through a subject's blood brain barrier of claim 16 (b) .

18. A vector comprising the nucleic acid of claim 17.

19. A composition comprising(a) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, of claim 15 or 16,(b) a nucleic acid of claim 17, or(c) a vector of claim 18.

20. A pharmaceutical composition comprising(a) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, of claim 15 or 16,(b) a nucleic acid of claim 17, or(c) a vector of claim 18, and a pharmaceutically acceptable carrier and / or diluent.

21. A kit comprising(a) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or a conservative variant thereof, of claim 15 or 16,(b) a nucleic acid of claim 17,(c) a vector of claim 18,(d) a pharmaceutical composition of any one of claims 1 to 14, or 20, or(e) a composition of claim 19, and optionally instructions for use.

22. A method of treatment and / or prevention of a neurodevelopmental, a neurological or a psychiatric disorder or disease related to the hippocampus, comprising administering(a) a C-terminal fragment of the Astrocytic phosphoprotein (PEA- 15) protein as set forth in SEQ ID NO. 2, or conservative variant thereof, of claim 15 or 16,(b) a nucleic acid of claim 17,(c) a vector of claim 18, or(d) a pharmaceutical composition of any one of claims 1 to 14, or 20.

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