Epithelial na+ channel modulators and uses thereof

Abstract

The present invention provides, inter alia, apelin receptor agonists having increased half-life, reduced desensitization, improved apelin receptor signaling properties (e.g., bias of G a signaling over arrestin signaling), enhanced stability, and / or enhanced binding to apelin receptors.

Description

[0001] Cross-reference to related applications This application is a divisional application of Chinese Patent Application No. 202480038785.3, filed on April 11, 2024, entitled "Apalinide Receptor Agonist and Its Use Thereof". The original application was a national phase application with international application No. PCT / US2024 / 024147, which claims priority to U.S. Provisional Application Serial No. 63 / 585,027, filed on September 25, 2023, and U.S. Provisional Application Serial No. 63 / 495,388, filed on April 11, 2023. The disclosure of the aforementioned U.S. Provisional Applications is hereby incorporated herein by reference in its entirety.

[0002] By referencing and incorporating into the sequence list This application contains a sequence list that has been electronically submitted in XML format, and is hereby incorporated in its entirety by reference. The sequence list file, entitled “023236_8150CN02_SeqL_ST26.xml”, was created on April 7, 2026, and has a size of 83,478 bytes. Background Technology

[0003] The apelin system is an endogenous physiological regulator that has emerged as a potential therapeutic target for many diseases. This system comprises the apelin receptor and its two endogenous ligand families, apelin and elabela / toddler (ELA; also known as the early endogenous ligand of the apelin receptor). The APLNR gene (also known as APJ) was identified and cloned in 1993. This gene was found to encode the apelin receptor, a novel G protein-coupled receptor (GPCR) that shares approximately 50% homology with the type 1 angiotensin II (AT1) receptor. The apelin receptor system antagonizes the agonistic effect of angiotensin II (Ang II) on the AT1 receptor both in vitro and in vivo. The apelin receptor is highly conserved among species with approximately 90% sequence similarity between the mouse, rat, and human proteins.

[0004] Clinical studies of the apralinide system are challenging due to its short half-life of only a few minutes in humans and the reported rapid receptor desensitization via conjugation to β-inhibitor protein. These challenges have led to efforts to develop apralinide receptor agonists that can be used as pharmacological probes to explore the system's role in health and disease. Summary of the Invention

[0005] The present invention particularly provides improved apralin peptide receptor agonists and the use of such agonists in the effective treatment of diseases such as pulmonary hypertension (PAH), systemic sclerosis (SSc), heart failure with preserved ejection fraction (HfpEf), age-related sarcopenia, and acute kidney injury (AKI).

[0006] As described herein, the present invention is based in part on the identification of novel ipralinide or ipralinide analogues having increased half-life, reduced desensitization, improved ipralinide receptor signaling properties (e.g., bias towards Gα signaling relative to β-inhibitor signaling), enhanced stability, and / or enhanced binding to the ipralinide receptor. This is significant because the ipralinide receptor agonists of the present invention can effectively elicit a response to the desired downstream ipralinide receptor pathway without significantly adversely affecting the internalization and transcriptional downregulation of the ipralinide receptor following treatment with the ipralinide receptor agonists. The inventive ipralinide receptor agonists of the present invention may more effectively treat ipralinide receptor-mediated diseases and conditions, including pulmonary arterial hypertension (PAH), systemic sclerosis (SSc), heart failure with preserved ejection fraction (HfpEf), age-related sarcopenia, and acute kidney injury (AKI).

[0007] In one aspect, the present invention provides an apralin peptide receptor agonist comprising an apralin peptide analogue, wherein the apralin peptide analogue comprises one or more amino acid substitutions relative to SEQ ID NO: 1 (QRPRLSHKGPMPF), wherein the one or more amino acid substitutions occur at positions 1, 6, 8, 9, 11, 12 and / or 13.

[0008] In some embodiments, the apalin peptide receptor agonist comprises one or more amino acid substitutions selected from the following: P12V, K8W, Q1E, M11H, M11A, F13Y and / or P12A, P12H, F13W, S6Q and / or G9N.

[0009] In one aspect, the present invention provides an apralin peptide receptor agonist comprising an apralin peptide analogue, wherein the apralin peptide analogue comprises the following amino sequence: X1-RPRLSH-X2-GP-X3-X4-X5 (SEQ ID NO: 63), wherein X1 is Q or E; X2 is K or W; X3 is M, H or A; X4 is P, V, A or H; and / or X5 is F, Y or W.

[0010] In one aspect, the present invention provides an apralin peptide receptor agonist comprising an apralin peptide analog, wherein the apralin peptide analog comprises the following amino sequence: QRPRLQHKNPMA-X1 (SEQ ID NO:64), wherein X1 is F or W.

[0011] In one aspect, the present invention provides an apralin receptor agonist comprising an apralin analogue, wherein the apralin analogue comprises the following amino sequence: QRPRLSHKGP-X1-X2-X3 (SEQ ID NO:65), wherein X1 is M, H or A; X2 is P, V, A or H; and / or X3 is F, Y or W.

[0012] In one aspect, the present invention particularly provides an apralin peptide receptor agonist comprising an apralin peptide analogue, wherein the apralin peptide analogue comprises the following amino sequence: X1-RPRL-X2-H-X3-X4-P-X5-X6-X7 (SEQ ID NO: 66), wherein X1 is Q or E; X2 is S or Q; X3 is K or W; X4 is G or N; X5 is M, H or A; X6 is P, V, A or H; and / or X7 is F, Y or W.

[0013] In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 1 (QRPRLSHKGPMPF). In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 2 (QRPRLSHKGPMVF). In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 3 (QRPRLSHWGPMPF). In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 4 (ERPRLSHKGPMPF). In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 5 (QRPRLSHKGPHPF). In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 6 (QRPRLSHKGPAPY). In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 7 (QRPRLSHKGPMAF). In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 50 (QRPRLSHKGPMHW). In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 51 (QRPRLSHKGPAAW). In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 52 (QRPRLSHKGPAAY). In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 55 (QRPRLSHWGPMAW). In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 53 (QRPRLQHKNPMAF). In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 54 (QRPRLQHKNPMAW).

[0014] In one aspect, the present invention provides an apralinide receptor agonist comprising an alabera peptide analogue, wherein the alabera peptide analogue comprises one or more amino acid substitutions relative to SEQ ID NO: 8 (KLRKHNCLQRRCMPLHSRVPFP), wherein the one or more amino acid substitutions occur at positions 3, 7, 8, 9, 10, 12, 14, 15, 17 and / or 18.

[0015] In some embodiments, the apalin peptide analogue comprises one or more amino acid substitutions, the one or more amino acid substitutions comprising R3N, P14I, S17Q, S17R, Q9K, R18Y, L15Y, C7S, C12Y, R10E, Q9I, L8A and / or Q9T.

[0016] In one aspect, the present invention provides an ipalin peptide receptor agonist comprising an ipalabeptide analogue, wherein the ipalabeptide analogue comprises the following amino sequence: KL-Z1-KHN-Z2-Z3-Z4-Z5-R-Z6-M-Z7-Z8-H-Z9-Z10-VPFP (SEQ ID NO: 67), wherein Z1 is R or N; Z2 is C or S; Z3 is A or L; Z4 is Q, I, K or T; Z5 is R or E; Z6 is C or Y; Z7 is P or I; Z8 is L or Y; Z9 is S, Q or R; and / or Z10 is R or Y.

[0017] In some embodiments, the alabella peptide analog comprises the amino acid sequence of SEQ ID NO: 8 (KLRKHNCLQRRCMPLHSRVPFP). In some embodiments, the alabella peptide analog comprises the amino acid sequence of SEQ ID NO: 9 (KLNKHNCLQRRCMPLHSRVPFP). In some embodiments, the alabella peptide analog comprises the amino acid sequence of SEQ ID NO: 10 (KLRKHNCLQRRCMILHSRVPFP). In some embodiments, the alabella peptide analog comprises the amino acid sequence of SEQ ID NO: 11 (KLRKHNCLQRRCMPLHQRVPFP). In some embodiments, the alabella peptide analog comprises the amino acid sequence of SEQ ID NO: 12 (KLRKHNCLQRRCMPLHRRVPFP). In some embodiments, the alabella peptide analog comprises the amino acid sequence of SEQ ID NO: 13 (KLRKHNCLKRRCMPLHSRVPFP). In some embodiments, the alabella peptide analog comprises the amino acid sequence of SEQ ID NO: 30 (KLRKHNCLQRRCMPLHSYVPFP). In some embodiments, the alabella peptide analog comprises the amino acid sequence of SEQ ID NO: 31 (KLRKHNCLQRRCMPYHSRVPFP). In some embodiments, the alabella peptide analog comprises the amino acid sequence of SEQ ID NO: 32 (KLRKHNSLQRRYMPLHSRVPFP). In some embodiments, the alabella peptide analog comprises the amino acid sequence of SEQ ID NO: 33 (KLRKHNCLQERCMPLHSRVPFP). In some embodiments, the alabella peptide analog comprises the amino acid sequence of SEQ ID NO: 34 (KLRKHNCLIRRCMPLHSRVPFP). In some embodiments, the alabella peptide analog comprises the amino acid sequence of SEQ ID NO: 35 (KLRKHNCATRRCMPLHSRVPFP).

[0018] In some embodiments, the apralin receptor agonist comprises an apralin analogue or the ilabella peptide analogue fused to a carrier portion. In some embodiments, the N-terminus of the apralin analogue or the ilabella peptide analogue is fused to the carrier portion. In some embodiments, the carrier portion prolongs the half-life of the apralin receptor agonist. In some embodiments, the carrier portion comprises an Fc domain, human serum albumin (HSA), an anti-HSA antibody or a fragment thereof, lipids, or PEG. In some embodiments, the Fc domain is a monovalent Fc. In some embodiments, the Fc domain is a divalent Fc.

[0019] In some embodiments, the anti-HSA antibody or a fragment thereof is an anti-HSA Fab, a nanobody (VHH), scFv, or V-NAR. In some embodiments, the anti-HSA VHH comprises ALB-23.

[0020] In one aspect, the present invention particularly provides an apralin peptide analog or an alabella peptide analog, wherein the N-terminus of the apralin peptide analog or the alabella peptide analog is partially fused to a carrier via a linker.

[0021] In some embodiments, the N-terminus of the apralin peptide analog or the alabelatine peptide analog is fused to the C-terminus of the carrier portion. In some embodiments, the carrier portion extends the half-life of the apralin peptide receptor agonist. In some embodiments, the carrier portion comprises an Fc domain, human serum albumin (HSA), an anti-HSA antibody or a fragment thereof, lipids, or PEG. In some embodiments, the Fc domain is a monovalent Fc. In some embodiments, the Fc domain is a divalent Fc. In some embodiments, the Fc domain is an IgG1, IgG2, IgG3, or IgG4 isotype. In some embodiments, the Fc domain comprises one or more mutations relative to the wild-type Fc domain. In some embodiments, the Fc domain comprises SEQ ID NO: 14 or SEQ ID NO: 15. In some embodiments, the anti-HSA antibody or a fragment thereof is an anti-HSA Fab, a nanobody (VHH), scFv, or V-NAR. In some embodiments, the anti-HAS VHH comprises ALB-23. In some embodiments, the connector comprises GGGGSGGGGSGGGGS (SEQ ID NO: 16).

[0022] In some embodiments, the apralin peptide receptor agonist comprises at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the amino acid sequence identical to that of SEQ ID NO: 17. In some embodiments, the apralin peptide receptor agonist comprises at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the amino acid sequence identical to that of SEQ ID NO: 18. In some embodiments, the apralin peptide receptor agonist comprises at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the amino acid sequence identical to that of SEQ ID NO: 19. In some embodiments, the apralin peptide receptor agonist comprises at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the amino acid sequence identical to that of SEQ ID NO: 20. In some embodiments, the apralin peptide receptor agonist comprises at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the amino acid sequence identical to that of SEQ ID NO: 21. In some embodiments, the apralin peptide receptor agonist comprises at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the amino acid sequence identical to that of SEQ ID NO: 22. In some embodiments, the apralin peptide receptor agonist comprises at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the amino acid sequence identical to that of SEQ ID NO: 23. In some embodiments, the apralin peptide receptor agonist comprises at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the amino acid sequence identical to that of SEQ ID NO: 24. In some embodiments, the apralin peptide receptor agonist comprises at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the amino acid sequence identical to that of SEQ ID NO: 25. In some embodiments, the apralin peptide receptor agonist comprises at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the amino acid sequence identical to that of SEQ ID NO: 26. In some embodiments, the apralin peptide receptor agonist comprises at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the amino acid sequence identical to that of SEQ ID NO: 27. In some embodiments, the apralin peptide receptor agonist comprises at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the amino acid sequence identical to that of SEQ ID NO: 28. In some embodiments, the apralin peptide receptor agonist comprises at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the amino acid sequence identical to that of SEQ ID NO: 29.In some embodiments, the apralin peptide receptor agonist comprises at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the amino acid sequence identical to that of SEQ ID NO: 36. In some embodiments, the apralin peptide receptor agonist comprises at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the amino acid sequence identical to that of SEQ ID NO: 37. In some embodiments, the apralin peptide receptor agonist comprises at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the amino acid sequence identical to that of SEQ ID NO: 38. In some embodiments, the apralin peptide receptor agonist comprises at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the amino acid sequence identical to that of SEQ ID NO: 39. In some embodiments, the apralin peptide receptor agonist comprises at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the amino acid sequence identical to that of SEQ ID NO: 40. In some embodiments, the apralin peptide receptor agonist comprises at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the amino acid sequence identical to that of SEQ ID NO: 41. In some embodiments, the apralin peptide receptor agonist comprises at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the amino acid sequence identical to that of SEQ ID NO: 56. In some embodiments, the apralin peptide receptor agonist comprises at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the amino acid sequence identical to that of SEQ ID NO: 57. In some embodiments, the apralin peptide receptor agonist comprises at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the amino acid sequence identical to that of SEQ ID NO: 59. In some embodiments, the apralin peptide receptor agonist comprises at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 60. In some embodiments, the apralin peptide receptor agonist comprises at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 61.

[0023] In some embodiments, the G of the apalinide receptor agonist αiThe EC50 value for signal transduction assays is less than 60 nM, less than 30 nM, less than 20 nM, or less than 10 nM, as measured by cAMP depletion. In some embodiments, the EC50 value for β-repressor signal transduction assays of the apalinide receptor agonist is less than 60 nM, less than 500 nM, less than 100 nM, less than 30 nM, or less than 10 nM. In some embodiments, the EC50 value for ERK activation assays of the apalinide receptor agonist is less than 20 nM, less than 10 nM, less than 5 nM, less than 2 nM, or less than 1 nM.

[0024] In one aspect, the present invention provides a method for treating a disease, the method comprising administering the apralinide receptor agonist of the present invention to a subject in need. In some embodiments, the disease is pulmonary arterial hypertension (PAH), systemic sclerosis (SSc), heart failure with preserved ejection fraction (HfpEf), age-related sarcopenia, or acute kidney injury (AKI).

[0025] In some embodiments, this disclosure covers nucleic acids encoding the ipalin peptide receptor agonist disclosed herein. In some embodiments, this disclosure covers a method for generating the ipalin peptide receptor agonist disclosed herein. Attached Figure Description

[0026] Figure 1 This is an exemplary schematic diagram illustrating how activation of the apralin peptide receptor, mediated by several signal transduction pathways, leads to a wide range of physiological effects.

[0027] Figure 2 This is an exemplary graph showing the internalization score of exemplary apralin peptide analogs relative to EC50 values ​​of β-inhibitory protein signaling and cAMP signaling.

[0028] Figure 3 This is an exemplary graph showing the internalization score of exemplary alabera peptide analogs relative to β-inhibitory protein signaling and cAMP signaling.

[0029] definition To facilitate understanding of this disclosure, certain terms are defined below. Further definitions for these and other terms are set forth throughout the specification. Publications and other references mentioned herein that describe the background of this disclosure and provide further details on its practice are hereby incorporated by reference.

[0030] Apalin peptide receptor agonists —The term "apralinide receptor agonist" refers to a non-naturally occurring peptide or polypeptide that has improved agonistic activity against the apralinide receptor. In some embodiments, apralinide receptor analogs have enhanced binding to the apralinide receptor compared to wild-type apralinide. In some embodiments, apralinide receptor analogs have improved apralinide receptor signaling compared to wild-type apralinide. In some embodiments, apralinide receptor analogs have an increased half-life compared to wild-type apralinide. In some embodiments, apralinide receptor analogs are more resistant to proteolytic degradation compared to wild-type apralinide. In some embodiments, apralinide receptor analogs comprise a carrier and wild-type apralinide. In some embodiments, apralinide receptor analogs comprise a carrier and wild-type iprameptide.

[0031] Fc —The term “Fc” refers to a portion of the heavy chain constant region that contains at least the CH2 and CH3 domains that typically bind to Fc receptors (e.g., FcγR, i.e., FcγRI (CD64), FcγRII (CD32), FcγRIII (CD16), or FcRn, i.e., the neonatal Fc receptor). The Fc variants of the present invention can be optimized for a variety of properties. Fc variants engineered or predicted to exhibit one or more optimized properties are referred to herein as “optimized Fc variants.” In some embodiments, the optimized Fc variants have reduced or ablated affinity for FcγRI, FcγRIIa, FcγRIIb, FcγRIIIa, FcγRIIIb, and C1q, and retain binding to FcRn.

[0032] Increased half-life —As used herein, “increased half-life” or “increased serum half-life” or “prolonged half-life” refers to a positive change in the circulating half-life of a modified bioactive molecule (e.g., apralin or ilabelatin analogues) relative to its unmodified form (or the naked form of the peptide). For example, serum half-life is measured by collecting blood samples at various time points after administration of the bioactive molecule and determining the concentration of the molecule in each sample.

[0033] Pharmaceutically acceptable —As used in this article, “pharmaceutically acceptable” means that it is generally recognized for use in animals, and more specifically in humans.

[0034] Pharmaceutically acceptable excipients As used herein, “pharmaceuticalally acceptable excipient,” “pharmaceuticalally acceptable carrier,” or “pharmaceuticalally acceptable adjuvant” refers to an excipient, carrier, or adjuvant used to administer at least one compound of this disclosure. “Pharmaceuticalally acceptable carrier” refers to a diluent, adjuvant, excipient, or carrier administered together with at least one compound of this disclosure.

[0035] Subjects —As used herein, “subject” includes mammals and humans. The terms “human” and “subject” are used interchangeably in this document.

[0036] Therapeutic effective dose —As used herein, a “therapeutic effective amount” means an amount of compound that, when administered to a subject to treat at least one of the clinical symptoms of a disease or condition, is sufficient to affect the treatment of the disease, condition, or symptom. A “therapeutic effective amount” can vary depending on the compound, the disease, condition, and / or symptoms of the disease or condition, the severity of the symptoms, the age of the subject to be treated, and / or the weight of the subject to be treated. An appropriate amount in any given situation can be readily and obviously determined by one of those skilled in the art or can be determined by routine experiments.

[0037] treat —As used herein, “treating” any disease or condition means preventing or improving the disease, condition, or at least one clinical symptom of the disease or condition, reducing the risk of having, developing, or exhibiting at least one clinical symptom of the disease, condition, or condition, reducing the progression of, or developing at least one clinical symptom of the disease, condition, or condition. “Treatment” also means suppressing a disease or condition physically (e.g., stabilization of identifiable symptoms), physiologically (e.g., stabilization of physical parameters), or both, or suppressing at least one physical parameter that may not be identifiable to the subject. Additionally, “treating” means delaying the onset of a disease or condition, or at least its symptoms, in a subject who may be exposed to or susceptible to the disease or condition, even if the subject has not yet experienced or exhibited symptoms of the disease or condition.

[0038] variants—As used herein, “variant,” “analyte,” and “mutant protein” refer to a bioactive derivative of a reference molecule that retains the desired activity, such as the activity of apralinide for the treatment of cardiovascular or pulmonary diseases or conditions as described herein. Generally, the terms “variant” and “analyte” refer to compounds having a native polypeptide sequence and structure with one or more amino acid additions, substitutions (generally conserved in nature), and / or deletions relative to the native molecule, provided that the modifications do not impair bioactivity and are “substantially homologous” to the reference molecule as defined below. Generally, when two sequences are aligned, the amino acid sequence of such an analog will have a high sequence homology to the reference sequence, for example, greater than 50%, typically greater than 60%–70%, and even more specifically 80%–85% or more, such as at least 90%–95% or more. Typically, an analog will comprise the same number of amino acids but will include substitutions, as explained herein. The term "mutant protein" further includes polypeptides having one or more amino acid-like molecules, including but not limited to compounds containing only amino and / or imino molecules, polypeptides containing one or more analogs of amino acids (including, for example, non-natural amino acids), polypeptides having substituted bonds, and other modifications known in the art, including naturally occurring and non-naturally occurring (e.g., synthetic), cyclized, branched molecules, etc. The term also includes molecules containing one or more N-substituted glycine residues ("peptide-like molecules") and other synthetic amino acids or peptides. (See, for example, U.S. Patents 5,831,005, 5,877,278, and 5,977,301; Nguyen et al., *ChemBiol.* (2000) 7:463-473; and Simon et al., *Proceedings of the National Academy of Sciences of the United States of America* (1992) 89:9367-9371, for the description of peptide-like molecules). Preferably, the analog or mutant protein has at least the same apalaline peptide biological activity as the natural molecule. Methods for preparing peptide analogs and mutant proteins are known in the art and are further described below. Detailed Implementation

[0039] Apalin peptide receptor pathway The apralinide system is an endogenous physiological regulator that has emerged as a potential therapeutic target for many diseases. This system comprises the apralinide receptor and its two endogenous ligand families, apralinide and ellabellainide / infant peptide (ELA; also known as the early endogenous ligand of the apralinide receptor).

[0040] The APLNR gene (also known as APJ) was identified and cloned in 1993. This gene was found to encode the apralin receptor, a novel G protein-coupled receptor (GPCR) that shares approximately 50% homology with the type 1 angiotensin II (AT1) receptor. The apralin receptor system antagonizes the agonistic effect of angiotensin II (Ang II) on the AT1 receptor both in vitro and in vivo. In the cardiovascular system, apralin and the AT1 receptor are co-expressed. The apralin receptor is highly conserved among species with approximately 90% sequence similarity between the mouse, rat, and human proteins.

[0041] Aipalin peptide Apalin peptide is produced by cleavage of the C-terminus of the 77-amino acid precursor, pre-pro-apelin. Peptide fragments of varying lengths circulate in vivo; the main isoforms are apalin peptide-36, apalin peptide-17, and apalin peptide-13. Compared to apalin peptide-13, the pyroglutamylated form [Pyr1]apalin peptide-13 is structurally more resistant to aminopeptidase metabolism and is the most abundant apalin peptide isoform in the cardiovascular system and human plasma.

[0042] The mechanism of apralin peptide metabolism is not fully defined. Experimental evidence suggests that furin protease (also known as PCSK3), plasma kallikrein, and neprilysin cleave apralin peptides, but only neprilysin has been shown to completely inactivate these peptides. Carboxypeptidase angiotensin-converting enzyme 2 (ACE2) has been clearly demonstrated to cleave the apralin peptide isoform both in vitro and in vivo, resulting in the removal of the common C-terminal phenylalanine. This enzyme is highly expressed on the surface of alveolar epithelial cells and intestinal epithelial cells, and expressed at lower levels in most organs, including the kidneys and heart, as well as on arterial and venous endothelial cells.

[0043] Alabella peptide ELA is a 54-amino acid peptide that is predicted to be processed to form mature peptides including ELA-32, ELA-21, and ELA-11. The discovery that ELA acts as a second endogenous ligand for the apralin receptor provides an explanation for the unexpected and significant phenotypic differences between apralin receptor knockout mice and apralin knockout mice, which are not born at the expected Mendelian ratio and exhibit significant cardiovascular developmental defects, while apralin knockout mice develop normally. ELA is detectable in human plasma, but its specific tissue isotype expression has not yet been explored.

[0044] Expression of the Apalin peptide system Aparynin and its receptor are widely expressed in the central nervous system and peripheral organs. Aparynin receptor mRNA has been detected in numerous tissues in rodents and humans, particularly in the brain, spinal cord, placenta, lungs, heart, kidneys, adipose tissue, and skeletal muscle. Aparynin receptor proteins have been identified in the brain, spinal cord, heart, kidneys, and lungs of rats and humans. In the human heart, the aparynin receptor is expressed by cardiomyocytes, endocardium, and endothelial cells of intracardiac vessels, as well as smooth muscle cells of ductal arteries and veins. In the kidneys, the aparynin receptor protein is localized in the cortex and vascular system.

[0045] Apalin peptide receptor binding and signal transduction In cellular expression systems and in rat and human cardiovascular tissues, endogenous apralin peptide isoforms bind to their homologous receptors with nanomolar affinity. However, structural activity studies have shown that longer isoforms (such as apralin peptide-36, and especially apralin peptide-17) have relatively shorter isoforms (such as [Pyr 1 [Apalin peptide-13] has a slightly higher affinity. It is present in all longer apalin peptide isoforms [Pyr] 1 The N-terminal RPRL sequence of apralineptide-13 is essential for receptor binding, with contributions from other residues such as Pro12. The minimal apralineptide fragment retains biological activity despite reduced affinity; the 10-amino acid apralineptide-13... （2-11） .

[0046] The crystal structure of the apralin peptide receptor complexed with a 17-amino acid non-endogenous apralin peptide agonist has been reported. Successful crystallization of the receptor requires extensive mutations. However, using this structure in conjunction with molecular dynamics simulations and molecular modeling, the study confirmed a two-site peptide-ligand binding mode. This 'message address' concept of peptide binding was also proposed in earlier studies, including the amino acids in the N-terminal tail and the first extracellular loop, which demonstrates a concept important for both receptor protein folding and apralin peptide binding. In another structural study, the upper surface of the apralin peptide receptor binding site was visualized using a 3D homology model, and site-directed mutagenesis confirmed the [Pyr] binding site. 1 The interaction between the basic residues in the N-terminal RPRL of Epalin peptide-13 and the acidic residues in extracellular loops I and II, as well as the interface between extracellular loop III and transmembrane VII.

[0047] Although the predicted isotypes ELA-32, ELA-21, and ELA-11 bind to the apralin peptide receptor in the human heart; ELA-32 binds with sub-nanomolar affinity, and ELA-21 binds with nanomolar affinity (to [Pyr 1ELA-11 (the shortest isoform) binds to ipalin peptide-13 (comparable to ipalin peptide), and the shortest isoform ELA-11 binds with an affinity order of magnitude lower than the other peptides, while the ELA peptide still shows very little sequence similarity to ipalin peptide. Alanine scanning and mutagenic analysis showed that ipalin peptide and ELA peptide bind to different residues in the rat and human ipalin peptide receptors.

[0048] Apalin peptide receptor and pertussis toxin-sensitive inhibitory G protein (Gα) i / o This couples with, subsequently activating the extracellular regulated kinase (ERK) and phosphoinositol 3-kinase (PI3K)-AKT (also known as protein kinase B (PKB)) signaling cascades. These cascades lead to a wide range of physiological effects, depending on the type of cell activated. All putative apralin peptides and ELA isotypes induce conventional G-reactive protein (GRP) activation of adenylate cyclase. i This mediated inhibition leads to the suppression of cAMP. Similar to other GPCRs, the apralin receptor can bind to other heterotrimeric G proteins, particularly G... q This binding leads to downstream stimulation of the phospholipase C (PLC) and AMP-activated protein kinase (AMPK) pathways.

[0049] Upon activation, GPCRs can decouple from their G proteins and internalize by recruiting β-repressor proteins to the receptor. At least in vitro, the extent and kinetics of apralin receptor-mediated internalization can be isotype-specific, with apralin-36 considered to produce a longer internalization than [Pyr1]apralin-13. For successful clinical translation of apralin receptor agonists, the discovery that GPCR ligands can preferentially activate subsets of the GPCR signaling repertoire, or indeed stimulate some signaling pathways while inhibiting others—a so-called 'biased signaling'—is an important finding. Longer apralin ligand isotypes, such as apralin-36, apralin-17, ELA-32, and ELA-21, compared to [Pyr1]apralin-13, have shown some bias in β-repressor protein recruitment. The in vivo relevance of these observations to the physiology or pathophysiology of the apralin receptor remains to be determined.

[0050] Ligand-independent signaling via the apralinide receptor was also reported, and this may be pathologically important. In cells co-expressing the apralinide receptor, inhibition of Ang II-mediated AT1 receptor activation of downstream ERK1 and ERK2 phosphorylation was achieved, and this inhibition was eliminated by apralinide in a pertussis-sensitive manner. Subsequently, in a mouse model of chronic stress overload, genetic loss of the apralinide receptor was demonstrated to prevent cardiac hypertrophy and heart failure, while loss of apralinide had no effect. This difference may be explained by the later discovery of ELA. However, isolated cardiomyocytes from apralinide receptor knockout mice exhibited a reduced response to stretching, suggesting that the apralinide receptor can act as a mechanosensor even in the absence of a ligand. This stretching-mediated response was eliminated by knocking out β-repressor protein, and the response was attenuated by adding apralinide. Therefore, when activated by apralin, the apralin receptor may have a hypertrophic effect through β-repressor signaling in the absence of a ligand, and an anti-hypertrophic effect through a β-repressor-independent pathway.

[0051] Apalin peptide receptor agonists Apalin peptide analogs This invention particularly provides an apralinide analogue with improved agonistic activity to the apralinide receptor. In some embodiments, the apralinide analogue has enhanced binding to the apralinide receptor compared to wild-type apralinide. In some embodiments, the apralinide analogue has improved apralinide receptor signaling compared to wild-type apralinide. In some embodiments, the apralinide analogue has an increased half-life compared to wild-type apralinide. In some embodiments, the apralinide analogue is more resistant to proteolytic degradation compared to wild-type apralinide.

[0052] In some embodiments, the apralin peptide analogue is derived from wild-type apralin peptide-77 (MNLRLCVQALLLLWLSLTAVCGGSLMPLPDGNGLEDGNVRHLVQPRGSRNGPGPWQGGRRKFRRQRPRLSHKGPMPF) of SEQ ID NO: 42.

[0053] In some embodiments, the apralin peptide analog is derived from wild-type apralin peptide-36 (LVQPRGSRNGPGPWQGGRRKFRRQRPRLSHKGPMPF) of SEQ ID NO: 43. In some embodiments, the apralin peptide analog is derived from wild-type apralin peptide-17 (KFRRQRPRLSHKGPMPF) of SEQ ID NO: 44. In some embodiments, the apralin peptide analog is derived from wild-type apralin peptide-13 (QRPRLSHKGPMPF) of SEQ ID NO: 1. In some embodiments, the apralin peptide analog is derived from [pyr-Glu]apralin peptide-13 (ERPRLSHKGPMPF) of SEQ ID NO: 45.

[0054] In some embodiments, the apalaline peptide analogue comprises a modification relative to SEQ ID NO: 1, SEQ ID NO: 42, SEQ ID NO: 43, SEQ ID NO: 44, or SEQ ID NO: 45. In some embodiments, the modification is a substitution, insertion, or deletion of one or more amino acids.

[0055] In some embodiments, the apralin peptide analog comprises one or more amino acid substitutions at positions 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13 of SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises one or more amino acid substitutions at positions 1, 6, 8, 9, 11, 12, or 13 of SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises an amino acid substitution at position 12 of SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises an amino acid substitution at position 8 of SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises an amino acid substitution at position 1 of SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises an amino acid substitution at position 11 of SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises an amino acid substitution at position 13 of SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises amino acid substitutions at positions 11 and 13 of SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises amino acid substitutions at positions 12 and 13 of SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises amino acid substitutions at positions 11, 12, and 13 of SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises amino acid substitutions at positions 8, 9, and 12 of SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises amino acid substitutions at positions 8, 9, 12, and 13 of SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises amino acid substitutions at positions 8, 12, and 13 of SEQ ID NO: 1.

[0056] In some embodiments, the apralin peptide analog comprises a P12V amino acid substitution compared to SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises an M11H amino acid substitution compared to SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises a K8W amino acid substitution compared to SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises a Q1E amino acid substitution compared to SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises M11A and F13Y amino acid substitutions compared to SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises a P12A amino acid substitution compared to SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises an S6Q amino acid substitution compared to SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises a G9N amino acid substitution compared to SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises a P12H amino acid substitution compared to SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises amino acid substitutions relative to SEQ ID NO: 1, specifically F13W. In some embodiments, the apralin peptide analog comprises amino acid substitutions relative to SEQ ID NO: 1, specifically P12H and F13W. In some embodiments, the apralin peptide analog comprises amino acid substitutions relative to SEQ ID NO: 1, specifically M11A, P12A, and F13W. In some embodiments, the apralin peptide analog comprises amino acid substitutions relative to SEQ ID NO: 1, specifically M11A, P12A, and F13Y. In some embodiments, the apralin peptide analog comprises amino acid substitutions relative to SEQ ID NO: 1, specifically S6Q, G9N, and P12A. In some embodiments, the apralin peptide analog comprises amino acid substitutions relative to SEQ ID NO: 1, specifically S6Q, G9N, P12A, and F13W. In some embodiments, the apralin peptide analog comprises amino acid substitutions relative to SEQ ID NO: 1, specifically K8W, P12A, and F13W.

[0057] In some embodiments, the apralin peptide analogue comprises the amino acid sequence shown in Table 1.

[0058] Table 1. Exemplary Apalin peptide analogs In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 2. In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 3. In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 4. In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 5. In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 6. In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 7. In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 50. In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 51. In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 52. In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 53. In some embodiments, the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 54. In some embodiments, the apalin peptide analog comprises the amino acid sequence of SEQ ID NO: 55.

[0059] In some embodiments, the apralin peptide analog differs from SEQ ID NO: 1 by no more than 4 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 1 by no more than 3 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 1 by no more than 2 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 1 by no more than 1 amino acid residue.

[0060] In some embodiments, the apralin peptide analog differs from SEQ ID NO: 2 by no more than 3 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 2 by no more than 2 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 2 by no more than 1 amino acid residue.

[0061] In some embodiments, the apralin peptide analog differs from SEQ ID NO: 3 by no more than 3 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 3 by no more than 2 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 3 by no more than 1 amino acid residue.

[0062] In some embodiments, the apralin peptide analog differs from SEQ ID NO: 4 by no more than 3 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 4 by no more than 2 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 4 by no more than 1 amino acid residue.

[0063] In some embodiments, the apralin peptide analog differs from SEQ ID NO: 5 by no more than 3 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 5 by no more than 2 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 5 by no more than 1 amino acid residue.

[0064] In some embodiments, the apralin peptide analog differs from SEQ ID NO: 6 by no more than 3 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 6 by no more than 2 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 6 by no more than 1 amino acid residue.

[0065] In some embodiments, the apralin peptide analog differs from SEQ ID NO: 7 by no more than 3 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 7 by no more than 2 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 7 by no more than 1 amino acid residue.

[0066] In some embodiments, the apralin peptide analog differs from SEQ ID NO: 50 by no more than 3 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 50 by no more than 2 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 50 by no more than 1 amino acid residue.

[0067] In some embodiments, the apralin peptide analog differs from SEQ ID NO: 51 by no more than 3 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 51 by no more than 2 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 51 by no more than 1 amino acid residue.

[0068] In some embodiments, the apralin peptide analog differs from SEQ ID NO: 52 by no more than 3 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 52 by no more than 2 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 52 by no more than 1 amino acid residue.

[0069] In some embodiments, the apralin peptide analog differs from SEQ ID NO: 53 by no more than 3 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 53 by no more than 2 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 53 by no more than 1 amino acid residue.

[0070] In some embodiments, the apralin peptide analog differs from SEQ ID NO: 54 by no more than 3 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 54 by no more than 2 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 54 by no more than 1 amino acid residue.

[0071] In some embodiments, the apralin peptide analog differs from SEQ ID NO: 55 by no more than 3 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 55 by no more than 2 amino acid residues. In some embodiments, the apralin peptide analog differs from SEQ ID NO: 55 by no more than 1 amino acid residue.

[0072] In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 1. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 1.

[0073] In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 2. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 2. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 2. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 2. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 2. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 2. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 2. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 2.

[0074] In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 3. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 3. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 3. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 3. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 3. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 3. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 3. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 3.

[0075] In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 4. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 4. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 4. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 4. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 4. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 4. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 4. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 4.

[0076] In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 5. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 5. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 5. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 5. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 5. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 5. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 5. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 5.

[0077] In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 6. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 6. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 6. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 6. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 6. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 6. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 6. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 6.

[0078] In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 7. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 7. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 7. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 7. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 7. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 7. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 7. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 7.

[0079] In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 50. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 50. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 50. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 50. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 50. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 50. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 50. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 50.

[0080] In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 51. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 51. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 51. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 51. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 51. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 51. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 51. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 51.

[0081] In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 52. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 52. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 52. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 52. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 52. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 52. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 52. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 52.

[0082] In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 53. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 53. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 53. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 53. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 53. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 53. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 53. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 53.

[0083] In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 54. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 54. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 54. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 54. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 54. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 54. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 54. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 54.

[0084] In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 55. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 55. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 55. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 55. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 55. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 55. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 55. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 55.

[0085] In some embodiments, ipalin peptide analogs comprise an amino acid sequence X1-RPRLSH-X2-GP-X3-X4-X5 (SEQ ID NO: 63) in X1 is either Q or E; X2 is either K or W; X3 is M, H, or A; X4 is P, V, A, or H; and / or X5 can be F, Y, or W.

[0086] In some embodiments, ipalin peptide analogs comprise an amino acid sequence QRPRLQHKNPMA-X1 (SEQ ID NO: 64) in X1 is either F or W.

[0087] In some embodiments, ipalin peptide analogs comprise an amino acid sequence QRPRLSHKGP-X1-X2-X3 (SEQ ID NO: 65) in X1 is M, H, or A; X2 is P, V, A, or H; and / or X3 can be F, Y, or W.

[0088] In some embodiments, ipalin peptide analogs comprise an amino acid sequence X1-RPRL-X2-H-X3-X4-P-X5-X6-X7 (SEQ ID NO: 66) in X1 is either Q or E; X2 is either S or Q; X3 is either K or W; X4 is either G or N; X5 is M, H, or A; X6 is P, V, A, or H; and / or X7 can be F, Y, or W.

[0089] Alabella peptide analogues This invention particularly provides an ilabella peptide analog with improved agonistic activity against the ilabella peptide receptor. In some embodiments, the ilabella peptide analog exhibits enhanced binding to the ilabella peptide receptor compared to wild-type ilabella peptide. In some embodiments, the ilabella peptide analog exhibits improved ilabella peptide receptor signaling compared to wild-type ilabella peptide. In some embodiments, the ilabella peptide analog has an increased half-life compared to wild-type ilabella peptide. In some embodiments, the ilabella peptide analog is more resistant to proteolytic degradation compared to wild-type ilabella peptide.

[0090] In some embodiments, the alabella peptide analog is derived from wild-type alabella peptide-54 (MRFQQFLFAFFIFIMSLLLISGQRPVNLTMRRKLRKHNCLQRRCMPLHSRVPFP) of SEQ ID NO: 46. In some embodiments, the alabella peptide analog is derived from wild-type alabella peptide-32 (QRPVNLTMRRKLRKHNCLQRRCMPLHSRVPFP) of SEQ ID NO: 47. In some embodiments, the alabella peptide analog is derived from wild-type alabella peptide-22 (KLRKHNCLQRRCMPLHSRVPFP) of SEQ ID NO: 8. In some embodiments, the alabella peptide analog is derived from wild-type alabella peptide-21 (LRKHNCLQRRCMPLHSRVPFP) of SEQ ID NO: 48. In some embodiments, the alabella peptide analog is derived from wild-type alabella peptide-11 (CMPLHSRVPFP) of SEQ ID NO: 49.

[0091] In some embodiments, the alabera peptide analogue comprises a modification relative to SEQ ID NO: 8, SEQ ID NO: 46, SEQ ID NO: 47, SEQ ID NO: 48, or SEQ ID NO: 49. In some embodiments, the modification is a substitution, insertion, or deletion of one or more amino acids.

[0092] In some embodiments, the alabella peptide analog comprises one or more amino acid substitutions at positions 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, or 22 of SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises one or more amino acid substitutions at positions 3, 7, 8, 9, 10, 12, 14, 15, 17, or 18 of SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises an amino acid substitution at position 3 of SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises an amino acid substitution at position 7 of SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises an amino acid substitution at position 8 of SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises an amino acid substitution at position 9 of SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises an amino acid substitution at position 10 of SEQ ID NO: 8. In some embodiments, the alabella peptide analog contains an amino acid substitution at position 12 of SEQ ID NO: 8. In some embodiments, the alabella peptide analog contains an amino acid substitution at position 14 of SEQ ID NO: 8. In some embodiments, the alabella peptide analog contains an amino acid substitution at position 15 of SEQ ID NO: 8. In some embodiments, the alabella peptide analog contains an amino acid substitution at position 17 of SEQ ID NO: 8. In some embodiments, the alabella peptide analog contains an amino acid substitution at position 18 of SEQ ID NO: 8.

[0093] In some embodiments, the alabella peptide analog comprises an R3N amino acid substitution relative to SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises a P14I amino acid substitution relative to SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises an S17Q amino acid substitution relative to SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises an S17R amino acid substitution relative to SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises a Q9K amino acid substitution relative to SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises an R18Y amino acid substitution relative to SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises an L15Y amino acid substitution relative to SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises C7S and C12Y amino acid substitutions relative to SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises an R10E amino acid substitution relative to SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises a Q9I amino acid substitution relative to SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises L8A and Q9T amino acid substitutions relative to SEQ ID NO: 8.

[0094] In some embodiments, the apalaline peptide analogue comprises the amino acid sequence shown in Table 2.

[0095] Table 2. Exemplary Alabella peptide analogues In some embodiments, the alabella peptide analog comprises the amino acid sequence of SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises the amino acid sequence of SEQ ID NO: 9. In some embodiments, the alabella peptide analog comprises the amino acid sequence of SEQ ID NO: 10. In some embodiments, the alabella peptide analog comprises the amino acid sequence of SEQ ID NO: 11. In some embodiments, the alabella peptide analog comprises the amino acid sequence of SEQ ID NO: 12. In some embodiments, the alabella peptide analog comprises the amino acid sequence of SEQ ID NO: 13. In some embodiments, the alabella peptide analog comprises the amino acid sequence of SEQ ID NO: 30. In some embodiments, the alabella peptide analog comprises the amino acid sequence of SEQ ID NO: 31. In some embodiments, the alabella peptide analog comprises the amino acid sequence of SEQ ID NO: 32. In some embodiments, the alabella peptide analog comprises the amino acid sequence of SEQ ID NO: 33. In some embodiments, the alabella peptide analog comprises the amino acid sequence of SEQ ID NO: 34. In some embodiments, the alabella peptide analog comprises the amino acid sequence of SEQ ID NO: 35.

[0096] In some embodiments, the alabella peptide analog differs from SEQ ID NO: 8 by no more than 5 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 8 by no more than 4 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 8 by no more than 3 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 8 by no more than 2 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 8 by no more than 1 amino acid residue.

[0097] In some embodiments, the alabella peptide analog differs from SEQ ID NO: 9 by no more than 5 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 9 by no more than 4 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 9 by no more than 3 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 9 by no more than 2 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 9 by no more than 1 amino acid residue.

[0098] In some embodiments, the alabella peptide analog differs from SEQ ID NO: 10 by no more than 5 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 10 by no more than 4 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 10 by no more than 3 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 10 by no more than 2 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 10 by no more than 1 amino acid residue.

[0099] In some embodiments, the alabella peptide analog differs from SEQ ID NO: 11 by no more than 5 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 11 by no more than 4 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 11 by no more than 3 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 11 by no more than 2 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 11 by no more than 1 amino acid residue.

[0100] In some embodiments, the alabella peptide analog differs from SEQ ID NO: 12 by no more than 5 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 12 by no more than 4 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 12 by no more than 3 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 12 by no more than 2 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 12 by no more than 1 amino acid residue.

[0101] In some embodiments, the alabella peptide analog differs from SEQ ID NO: 13 by no more than 5 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 13 by no more than 4 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 13 by no more than 3 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 3 by no more than 2 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 13 by no more than 1 amino acid residue.

[0102] In some embodiments, the alabella peptide analog differs from SEQ ID NO: 30 by no more than 5 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 30 by no more than 4 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 30 by no more than 3 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 30 by no more than 2 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 30 by no more than 1 amino acid residue.

[0103] In some embodiments, the alabella peptide analog differs from SEQ ID NO: 31 by no more than 5 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 31 by no more than 4 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 31 by no more than 3 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 31 by no more than 2 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 31 by no more than 1 amino acid residue.

[0104] In some embodiments, the alabella peptide analog differs from SEQ ID NO: 32 by no more than 5 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 32 by no more than 4 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 32 by no more than 3 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 32 by no more than 2 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 32 by no more than 1 amino acid residue.

[0105] In some embodiments, the alabella peptide analog differs from SEQ ID NO: 33 by no more than 5 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 33 by no more than 4 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 33 by no more than 3 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 33 by no more than 2 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 33 by no more than 1 amino acid residue.

[0106] In some embodiments, the alabella peptide analog differs from SEQ ID NO: 34 by no more than 5 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 34 by no more than 4 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 34 by no more than 3 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 34 by no more than 2 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 34 by no more than 1 amino acid residue.

[0107] In some embodiments, the alabella peptide analog differs from SEQ ID NO: 35 by no more than 5 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 35 by no more than 4 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 35 by no more than 3 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 35 by no more than 2 amino acid residues. In some embodiments, the alabella peptide analog differs from SEQ ID NO: 35 by no more than 1 amino acid residue.

[0108] In some embodiments, the alabella peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 8.

[0109] In some embodiments, the alabella peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 9. In some embodiments, the alabella peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 9. In some embodiments, the alabella peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 9. In some embodiments, the alabella peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 9. In some embodiments, the alabella peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 9. In some embodiments, the alabella peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 9. In some embodiments, the alabella peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 9. In some embodiments, the alabella peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 9.

[0110] In some embodiments, the alabella peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 10. In some embodiments, the alabella peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 10. In some embodiments, the alabella peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 10. In some embodiments, the alabella peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 10. In some embodiments, the alabella peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 10. In some embodiments, the alabella peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 10. In some embodiments, the alabella peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 10. In some embodiments, the alabella peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 10.

[0111] In some embodiments, the alabella peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 11. In some embodiments, the alabella peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 11. In some embodiments, the alabella peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 11. In some embodiments, the alabella peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 11. In some embodiments, the alabella peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 11. In some embodiments, the alabella peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 11. In some embodiments, the alabella peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 11. In some embodiments, the alabella peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 11.

[0112] In some embodiments, the alabella peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 12. In some embodiments, the alabella peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 12. In some embodiments, the alabella peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 12. In some embodiments, the alabella peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 12. In some embodiments, the alabella peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 12. In some embodiments, the alabella peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 12. In some embodiments, the alabella peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 8. In some embodiments, the alabella peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 12.

[0113] In some embodiments, the alabella peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 13. In some embodiments, the alabella peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 13. In some embodiments, the alabella peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 13. In some embodiments, the alabella peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 13. In some embodiments, the alabella peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 13. In some embodiments, the alabella peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 13. In some embodiments, the alabella peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 13. In some embodiments, the alabella peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 13.

[0114] In some embodiments, the alabella peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 30. In some embodiments, the alabella peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 30. In some embodiments, the alabella peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 30. In some embodiments, the alabella peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 30. In some embodiments, the alabella peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 30. In some embodiments, the alabella peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 30. In some embodiments, the alabella peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 30. In some embodiments, the alabella peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 30.

[0115] In some embodiments, the alabella peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 31. In some embodiments, the alabella peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 31. In some embodiments, the alabella peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 31. In some embodiments, the alabella peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 31. In some embodiments, the alabella peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 31. In some embodiments, the alabella peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 31. In some embodiments, the alabella peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 31. In some embodiments, the alabella peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 31.

[0116] In some embodiments, the alabella peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 32. In some embodiments, the alabella peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 32. In some embodiments, the alabella peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 32. In some embodiments, the alabella peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 32. In some embodiments, the alabella peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 32. In some embodiments, the alabella peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 32. In some embodiments, the alabella peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 32. In some embodiments, the alabella peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 32.

[0117] In some embodiments, the alabella peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 33. In some embodiments, the alabella peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 33. In some embodiments, the alabella peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 33. In some embodiments, the alabella peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 33. In some embodiments, the alabella peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 33. In some embodiments, the alabella peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 33. In some embodiments, the alabella peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 33. In some embodiments, the alabella peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 33.

[0118] In some embodiments, the alabella peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 34. In some embodiments, the alabella peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 34. In some embodiments, the alabella peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 34. In some embodiments, the alabella peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 34. In some embodiments, the alabella peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 34. In some embodiments, the alabella peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 34. In some embodiments, the alabella peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 34. In some embodiments, the alabella peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 34.

[0119] In some embodiments, the alabella peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 35. In some embodiments, the alabella peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 35. In some embodiments, the alabella peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 35. In some embodiments, the alabella peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 35. In some embodiments, the alabella peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 35. In some embodiments, the alabella peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 35. In some embodiments, the alabella peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 35. In some embodiments, the alabella peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 35.

[0120] In some embodiments, ipalin peptide analogs comprise an amino acid sequence KL-Z1-KHN-Z2-Z3-Z4-Z5-R-Z6-M-Z7-Z8-H-Z9-Z10-VPFP (SEQ ID NO: 67) Z1 is either R or N; Z2 is either C or S; Z3 is either A or L; Z4 is Q, I, K, or T; Z5 is either R or E; Z6 is either C or Y; Z7 is either P or I; Z8 is either L or Y; Z9 is S, Q, or R; and / or Z10 is either R or Y.

[0121] carrier part In particular, the present invention provides an apralin peptide receptor agonist comprising an apralin peptide analog or an apralin peptide analog fused to a carrier portion.

[0122] Extended half-life In some embodiments, the carrier portion extends the half-life of the apralin receptor agonist. As peptides, apralin and ipabera peptide have half-lives of approximately several minutes. This short half-life is partly mediated by proteolytic degradation, which is carried out by numerous circulating proteases that recognize and cleave at specific sequences. In addition to proteolytic degradation, the peptide is also rapidly cleared from the blood via the kidneys. In some embodiments, the carrier portion prevents the apralin receptor agonist from being cleared by the kidneys. In some embodiments, the carrier portion prevents the apralin receptor agonist from undergoing proteolysis.

[0123] Fc structural domain In some embodiments, the carrier portion is an Fc domain. In some embodiments, the carrier portion is an Fc domain of IgG1. In some embodiments, the carrier portion is an Fc domain of IgG2. In some embodiments, the carrier portion is an Fc domain of IgG3. In some embodiments, the carrier portion is an Fc domain of IgG4.

[0124] In some embodiments, the Fc domain has reduced or eliminated effector functions. In some embodiments, the Fc domain has reduced or eliminated binding with all FcγRI, FcγRIIa, FcγRIIb, FcγRIIIa, FcγRIIIb and C1q, while maintaining its ability to bind with FcRn.

[0125] In some embodiments, the Fc domain is a modified Fc domain containing one or more mutations. The Fc variants of the present invention can be optimized for a variety of properties. Fc variants engineered or predicted to exhibit one or more optimized properties are referred to herein as “optimized Fc variants.” Properties that can be optimized include, but are not limited to, enhanced or reduced affinity for FcγR. In some embodiments, the Fc variants of the present invention are optimized to have reduced or ablated affinity for human FcγR, including but not limited to FcγRI, FcγRIIa, FcγRIIb, FcγRIIc, FcγRIIIa, and FcγRIIIb. These embodiments are intended to provide Fc peptides with enhanced therapeutic properties in humans, such as reduced effector function and reduced toxicity. In other embodiments, the Fc variants of the present invention provide enhanced affinity for one or more FcγR, but reduced affinity for one or more other FcγR. For example, the Fc variants of the present invention may have enhanced binding to FcγRIIIa, but reduced binding to FcγRIIb. Alternatively, the Fc variants of the present invention may have enhanced binding to FcγRIIa and FcγRI, but reduced binding to FcγRIIb. In yet another embodiment, the Fc variants of the present invention may have enhanced affinity for FcγRIIb, but reduced affinity for one or more activating FcγRs.

[0126] In some embodiments, the Fc variant has a reduced or ablative affinity for FcγRI. In some embodiments, the Fc variant has a reduced or ablative affinity for FcγRIIa. In some embodiments, the Fc variant has a reduced or ablative affinity for FcγRIIb. In some embodiments, the Fc variant has a reduced or ablative affinity for FcγRIIc. In some embodiments, the Fc variant has a reduced or ablative affinity for FcγRIIIa. In some embodiments, the Fc variant has a reduced or ablative affinity for FcγRIIIb. In some embodiments, the Fc variant has a reduced or ablative affinity for C1q. In some embodiments, the Fc variant has an enhanced affinity for FcRn. In some embodiments, the Fc variant maintains affinity for FcRn. In some embodiments, the Fc variant has a reduced or ablative affinity for FcγRI, FcγRIIa, FcγRIIb, FcγRIIIa, FcγRIIIb, and C1q. In some embodiments, the Fc variants have reduced or ablation affinity for FcγRI, FcγRIIa, FcγRIIb, FcγRIIIa, FcγRIIIb and C1q, and retain binding to FcRn.

[0127] In some embodiments, the Fc domain is a monovalent Fc domain. In some embodiments, the Fc domain is a human IgG1 monovalent Fc domain. In some embodiments, the Fc domain is a human IgG2 monovalent Fc domain. In some embodiments, the Fc domain is a human IgG3 monovalent Fc domain. In some embodiments, the Fc domain is a human IgG4 monovalent Fc domain. In some embodiments, the Fc domain is a modified human IgG1 monovalent Fc domain. In some embodiments, the Fc domain is a modified human IgG2 monovalent Fc domain. In some embodiments, the Fc domain is a modified human IgG3 monovalent Fc domain. In some embodiments, the Fc domain is a modified human IgG4 monovalent Fc domain.

[0128] In some embodiments, the Fc domain is a bivalent Fc domain. In some embodiments, the Fc domain is a human IgG1 bivalent Fc domain. In some embodiments, the Fc domain is a human IgG2 bivalent Fc domain. In some embodiments, the Fc domain is a human IgG3 bivalent Fc domain. In some embodiments, the Fc domain is a human IgG4 bivalent Fc domain. In some embodiments, the Fc domain is a modified human IgG1 bivalent Fc domain. In some embodiments, the Fc domain is a modified human IgG2 bivalent Fc domain. In some embodiments, the Fc domain is a modified human IgG3 bivalent Fc domain. In some embodiments, the Fc domain is a modified human IgG4 bivalent Fc domain. In some embodiments, the modified human IgG4 bivalent Fc domain contains an S228P substitution.

[0129] In some embodiments, the vector portion comprises SEQ ID NO: 14. In some embodiments, the Fc domain of IgG1 comprises SEQ ID NO: 14. In some embodiments, the monovalent Fc domain of human IgG1 comprises SEQ ID NO: 14.

[0130] DKTHTSPPSPAPEAAGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKT ISKAKGQPREPQVYTLPPSREEMTKNQVNLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLNSTLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 14) In some embodiments, the carrier portion comprises an amino acid sequence that is at least 80% identical to SEQ ID NO: 14. In some embodiments, the carrier portion comprises an amino acid sequence that is at least 85% identical to SEQ ID NO: 14. In some embodiments, the carrier portion comprises an amino acid sequence that is at least 88% identical to SEQ ID NO: 14. In some embodiments, the carrier portion comprises an amino acid sequence that is at least 90% identical to SEQ ID NO: 14. In some embodiments, the carrier portion comprises an amino acid sequence that is at least 92% identical to SEQ ID NO: 14. In some embodiments, the carrier portion comprises an amino acid sequence that is at least 93% identical to SEQ ID NO: 14. In some embodiments, the carrier portion comprises an amino acid sequence that is at least 94% identical to SEQ ID NO: 14. In some embodiments, the carrier portion comprises an amino acid sequence that is at least 95% identical to SEQ ID NO: 14. In some embodiments, the carrier portion comprises an amino acid sequence that is at least 96% identical to SEQ ID NO: 14. In some embodiments, the carrier portion comprises an amino acid sequence that is at least 97% identical to SEQ ID NO: 14. In some embodiments, the carrier portion comprises an amino acid sequence that is at least 98% identical to SEQ ID NO: 14. In some embodiments, the carrier portion comprises an amino acid sequence that is at least 99% identical to that of SEQ ID NO: 14.

[0131] In some embodiments, the vector portion comprises SEQ ID NO: 15. In some embodiments, the Fc domain of IgG1 comprises SEQ ID NO: 15. In some embodiments, the monovalent Fc domain of human IgG1 comprises SEQ ID NO: 15.

[0132] MRAWIFFLLCLAGRALADKTHTSPPSPAPEAAGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKA LPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVNLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLNSTLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO:15) In some embodiments, the carrier portion comprises an amino acid sequence that is at least 80% identical to SEQ ID NO: 15. In some embodiments, the carrier portion comprises an amino acid sequence that is at least 85% identical to SEQ ID NO: 15. In some embodiments, the carrier portion comprises an amino acid sequence that is at least 88% identical to SEQ ID NO: 15. In some embodiments, the carrier portion comprises an amino acid sequence that is at least 90% identical to SEQ ID NO: 15. In some embodiments, the carrier portion comprises an amino acid sequence that is at least 92% identical to SEQ ID NO: 15. In some embodiments, the carrier portion comprises an amino acid sequence that is at least 93% identical to SEQ ID NO: 15. In some embodiments, the carrier portion comprises an amino acid sequence that is at least 94% identical to SEQ ID NO: 15. In some embodiments, the carrier portion comprises an amino acid sequence that is at least 95% identical to SEQ ID NO: 15. In some embodiments, the carrier portion comprises an amino acid sequence that is at least 96% identical to SEQ ID NO: 15. In some embodiments, the carrier portion comprises an amino acid sequence that is at least 97% identical to SEQ ID NO: 15. In some embodiments, the carrier portion comprises an amino acid sequence that is at least 98% identical to SEQ ID NO: 15. In some embodiments, the carrier portion comprises an amino acid sequence that is at least 99% identical to that of SEQ ID NO: 15.

[0133] Other carrier parts In some embodiments, the carrier portion comprises a serum protein binding portion. In some embodiments, the carrier portion is human serum albumin (HSA). In some embodiments, the carrier portion comprises a protein or peptide that binds to HSA. In some embodiments, the carrier portion comprises an anti-HSA antibody or a fragment thereof. In some embodiments, the carrier portion comprises anti-HSA Fab. In some embodiments, the carrier portion comprises an anti-HSA nanobody (VHH). In some embodiments, the carrier portion comprises anti-HASscFv. In some embodiments, the carrier portion comprises anti-HSA V-NAR. In some embodiments, the carrier portion comprises anti-HSA VHH of ALB-23. ALB-23 is described in WO2012175400A1, the contents of which are incorporated herein by reference.

[0134] In some embodiments, the carrier portion comprises one or more lipids. The lipids may have or comprise a variety of lengths, chemical properties, linkers, and conjugates that are readily apparent to those skilled in the art. In some embodiments, the carrier portion comprises a saturated fatty acid. In some embodiments, the saturated fatty acid is linked to a peptide via its carboxyl group. In some embodiments, the saturated fatty acid comprises C 6-18 Saturated fatty acids (e.g., C6, C4)12 C 16 Or C 18 (Saturated fatty acids). In some embodiments, the carrier portion comprises saturated fatty acid. In some embodiments, the saturated fatty acid is linked to the peptide via a free end of a carboxylate group. In some embodiments, the saturated fatty acid comprises C 6-18 Saturated fatty acids (e.g., C6, C4) 12 C 16 Or C 18 Saturated fatty acids (Diacarboxylic acid).

[0135] In some embodiments, the carrier portion comprises one or more polyethylene glycol (PEG). PEG can have or contain various lengths, molecular weights, and linkers that are readily apparent to those skilled in the art. In some embodiments, the PEG is monodisperse. In some embodiments, the monodisperse PEG has 12-48 PEG repeating sequences (e.g., 12-24 repeating sequences, 12-36 repeating sequences, 24-48 repeating sequences, 24-36 repeating sequences, or 36-48 repeating sequences). In some embodiments, the PEG is polydisperse. In some embodiments, the polydisperse PEG has a molecular weight of 500 to 50,000 Daltons (e.g., 500-1,000 Da, 500-5,000 Da, 500-20,000 Da, 500-40,000 Da, 1,000-5,000 Da, 1,000-20,000 Da, 1,000-40,000 Da, 1,000-50,000 Da, 5,000-10,000 Da, 5,000-20,000 Da, 5,000-40,000 Da, 5,000-50,000 Da, 10,000-20,000 Da, 10,000-40,000 Da, 10,000-50,000 Da, 20,000-40,000 Da). (Da or 20,000-50,000 Da). In some embodiments, the molecular weight of the polydisperse PEG is 0.5 kDa, 1 kDa, 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, or 50 kDa. In some embodiments, the carrier portion comprises polydisperse PEG with a molecular weight of 1 kDa. In some embodiments, the carrier portion comprises polydisperse PEG with a molecular weight of 5 kDa. In some embodiments, the carrier portion comprises polydisperse PEG with a molecular weight of 10 kDa. In some embodiments, the carrier portion comprises polydisperse PEG with a molecular weight of 15 kDa. In some embodiments, the carrier portion comprises polydisperse PEG with a molecular weight of 20 kDa. In some embodiments, the carrier portion comprises polydisperse PEG with a molecular weight of 25 kDa. In some embodiments, the carrier portion comprises polydisperse PEG with a molecular weight of 30 kDa. In some embodiments, the carrier portion comprises polydisperse PEG with a molecular weight of 35 kDa. In some embodiments, the carrier portion comprises polydisperse PEG with a molecular weight of 40 kDa. In some embodiments, the carrier portion comprises polydisperse PEG with a molecular weight of 50 kDa.

[0136] In some embodiments, the carrier portion comprises a half-life-extending polypeptide. The half-life-extending polypeptide may have or contain various lengths, chemical properties, linkers, and conjugates that are readily apparent to those skilled in the art. In some embodiments, the half-life-extending polypeptide comprises repeating units of Pro-Ala-Ser (PAS). In some embodiments, the half-life-extending polypeptide comprises 50-500 repeating PAS units (e.g., 50-100 PAS units, 50-200 PAS units, 100-200 PAS units, 100-500 PAS units, or 200-500 PAS units).

[0137] In some embodiments, the half-life-extending peptide comprises the XTEN™ peptide. XTEN is described in US20150037359A1, the contents of which are incorporated herein by reference.

[0138] In some embodiments, the apralin peptide analog or the alabera peptide analog is not fused to the carrier portion. In some embodiments, the apralin peptide analog or the alabera peptide analog exists as a free peptide.

[0139] Exemplary Apalin peptide receptor agonists This invention particularly provides an apralin receptor agonist comprising an apralin peptide analog or an alabella peptide analog fused to a carrier portion via a linker. Specifically, this invention provides an apralin peptide receptor agonist comprising an apralin peptide analog or an alabella peptide analog, wherein the N-terminus of the apralin peptide analog or the alabella peptide analog is fused to a carrier portion via a linker. In some embodiments, the N-terminus of the apralin peptide analog is fused to the C-terminus of the carrier portion. In some embodiments, the N-terminus of the apralin peptide analog is fused to the C-terminus of an Fc domain. In some embodiments, the N-terminus of the apralin peptide analog is fused to the C-terminus of a monovalent Fc domain. In some embodiments, the N-terminus of the apralin peptide analog is fused to the C-terminus of a monovalent IgG1 Fc domain.

[0140] In some embodiments, the linker comprises glycine and serine residues. In some embodiments, the linker consists of glycine and serine residues. In some embodiments, the linker comprises the amino acid sequence of SEQ ID NO: 16 (GGGGSGGGGSGGGGS).

[0141] In some embodiments, the apalin peptide receptor agonist comprises the sequence shown in Table 3.

[0142] Table 3. Exemplary Apalin peptide receptor agonists In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 17. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 17. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 17. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 17. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 17. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 17. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 17. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 17. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 17. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 17. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 17. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 17. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 17.

[0143] In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 18. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 18. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 18. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 18. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 18. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 18. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 18. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 18. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 18. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 18. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 18. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 18. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 18.

[0144] In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 19. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 19. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 19. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 19. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 19. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 19. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 19. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 19. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 19. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 19. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 19. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 19. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 19.

[0145] In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 20. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 20. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 20. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 20. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 20. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 20. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 20. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 20. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 20. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 20. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 20. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 20. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 20.

[0146] In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 21. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 21. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 21. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 21. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 21. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 21. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 21. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 21. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 21. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 21. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 21. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 21. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 21.

[0147] In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 22. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 22. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 22. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 22. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 22. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 22. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 22. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 22. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 22. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 22. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 22. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 22. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 22.

[0148] In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 23. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 23. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 23. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 23. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 23. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 23. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 23. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 23. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 23. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 23. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 23. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 23. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 23.

[0149] In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 24. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 24. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 24. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 24. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 24. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 24. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 24. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 24. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 24. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 24. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 24. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 24. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 24.

[0150] In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 25. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 25. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 25. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 25. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 25. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 25. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 25. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 25. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 25. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 25. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 25. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 25. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 25.

[0151] In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 26. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 26. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 26. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 26. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 26. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 26. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 26. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 26. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 26. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 26. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 26. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 26. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 26.

[0152] In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 27. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 27. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 27. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 27. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 27. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 27. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 27. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 27. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 27. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 27. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 27. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 27. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 27.

[0153] In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 28. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 28. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 28. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 28. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 28. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 28. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 28. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 28. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 28. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 28. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 28. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 28. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 28.

[0154] In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 29. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 29. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 29. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 29. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 29. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 29. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 29. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 29. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 29. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 29. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 29. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 29. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 29.

[0155] In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 36. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 36. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 36. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 36. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 36. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 36. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 36. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 36. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 36. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 36. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 36. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 36. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 36.

[0156] In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 37. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 37. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 37. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 37. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 37. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 37. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 37. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 37. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 37. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 37. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 37. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 37. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 37.

[0157] In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 38. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 38. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 38. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 38. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 38. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 38. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 38. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 38. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 38. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 38. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 38. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 38. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 38.

[0158] In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 39. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 39. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 39. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 39. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 39. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 39. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 39. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 39. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 39. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 39. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 9. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 39. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 39.

[0159] In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 40. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 40. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 40. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 40. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 40. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 40. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 0. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 40. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 40. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 40. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 40. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 40. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 40.

[0160] In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 41. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 41. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 41. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 41. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 41. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 41. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 41. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 41. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 41. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 41. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 41. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 41. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 41.

[0161] In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 56. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 56. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 56. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 56. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 56. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 56. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 56. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 56. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 56. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 56. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 56. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 56. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 56.

[0162] In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 57. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 57. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 57. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 57. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 57. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 57. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 57. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 57. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 57. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 57. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 57. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 57. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 57.

[0163] In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 58. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 58. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 58. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 58. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 58. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 58. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 58. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 58. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 58. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 58. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 58. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 58. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 58.

[0164] In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 59. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 59. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 59. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 59. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 59. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 59. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 59. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 59. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 59. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 59. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 59. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 59. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 59.

[0165] In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 60. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 60. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 60. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 60. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 60. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 60. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 60. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 60. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 60. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 60. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 60. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 60. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 60.

[0166] In some embodiments, the apralin peptide analog comprises at least 80% of the sequence identical to SEQ ID NO: 61. In some embodiments, the apralin peptide analog comprises at least 82% of the sequence identical to SEQ ID NO: 61. In some embodiments, the apralin peptide analog comprises at least 84% of the sequence identical to SEQ ID NO: 61. In some embodiments, the apralin peptide analog comprises at least 86% of the sequence identical to SEQ ID NO: 61. In some embodiments, the apralin peptide analog comprises at least 88% of the sequence identical to SEQ ID NO: 61. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 61. In some embodiments, the apralin peptide analog comprises at least 92% of the sequence identical to SEQ ID NO: 61. In some embodiments, the apralin peptide analog comprises at least 95% of the sequence identical to SEQ ID NO: 61. In some embodiments, the apralin peptide analog comprises at least 90% of the sequence identical to SEQ ID NO: 61. In some embodiments, the apralin peptide analog comprises at least 96% of the sequence identical to SEQ ID NO: 61. In some embodiments, the apralin peptide analog comprises at least 97% of the sequence identical to SEQ ID NO: 61. In some embodiments, the apralin peptide analog comprises at least 98% of the sequence identical to SEQ ID NO: 61. In some embodiments, the apralin peptide analog comprises at least 99% of the sequence identical to SEQ ID NO: 61.

[0167] Leader sequence In some embodiments, the apralin receptor agonist includes a leader sequence. In some embodiments, the apralin receptor agonist includes a leader sequence at the N-terminus. In some embodiments, the apralin receptor agonist includes a leader sequence at the N-terminus of the vector portion. In some embodiments, the apralin receptor agonist includes a leader sequence at the N-terminus of the Fc domain. In some embodiments, the leader sequence is cleaved prior to secretion.

[0168] In some embodiments, the leader sequence comprises an osteonectin leader sequence. In some embodiments, the leader sequence comprises SEQ ID NO: 62 (MRAWIFFLLCLAGRALA). In some embodiments, the leader sequence comprises at least 80% of the same amino acid sequence as SEQ ID NO: 62. In some embodiments, the leader sequence comprises at least 85% of the same amino acid sequence as SEQ ID NO: 62. In some embodiments, the leader sequence comprises at least 90% of the same amino acid sequence as SEQ ID NO: 62. In some embodiments, the leader sequence comprises at least 92% of the same amino acid sequence as SEQ ID NO: 62. In some embodiments, the leader sequence comprises at least 95% of the same amino acid sequence as SEQ ID NO: 62. In some embodiments, the leader sequence comprises at least 98% of the same amino acid sequence as SEQ ID NO: 62. In some embodiments, the leader sequence comprises at least 99% of the same amino acid sequence as SEQ ID NO: 62.

[0169] Properties of Apalin peptide receptor agonists This application particularly provides apralin peptide receptor agonists comprising apralin peptide analogs or ilabella peptide analogs, which possess unexpectedly superior properties, including but not limited to improved signal transduction properties, longer half-life, and reduced desensitization compared to wild-type apralin peptide or ilabella peptide. In some embodiments, the apralin peptide receptor agonists of the present invention bind APJ with higher affinity and specificity compared to wild-type apralin peptide agonists.

[0170] Improved signal transduction in the APJ pathway Compared with wild-type or endogenous ipalin or iplabelatin, the ipalin receptor agonist of the present invention has improved signal transduction properties.

[0171] In some embodiments, the apralin receptor agonist is biased towards Gα signaling relative to β-repressor protein signaling. In some embodiments, the bias of the apralin receptor agonist towards Gα signaling is at least about 1.5 times that towards β-repressor protein signaling. In some embodiments, the bias of the apralin receptor agonist towards Gα signaling is at least about 2 times that towards β-repressor protein signaling. In some embodiments, the bias of the apralin receptor agonist towards Gα signaling is at least about 2.5 times that towards β-repressor protein signaling. In some embodiments, the bias of the apralin receptor agonist towards Gα signaling is at least about 3 times that towards β-repressor protein signaling. In some embodiments, the bias of the apralin receptor agonist towards Gα signaling is at least about 4 times that towards β-repressor protein signaling. In some embodiments, the bias of the apralin receptor agonist towards Gα signaling is at least about 5 times that towards β-repressor protein signaling. In some embodiments, the apralin receptor agonist is at least about 7 times more biased toward Gα signaling than it is toward β-repressor protein signaling. In some embodiments, the apralin receptor agonist is at least about 10 times more biased toward Gα signaling than it is toward β-repressor protein signaling. In some embodiments, the apralin receptor agonist is at least about 12 times more biased toward Gα signaling than it is toward β-repressor protein signaling. In some embodiments, the apralin receptor agonist is at least about 15 times more biased toward Gα signaling than it is toward β-repressor protein signaling. In some embodiments, the apralin receptor agonist is at least about 20 times more biased toward Gα signaling than it is toward β-repressor protein signaling. In some embodiments, the apralin receptor agonist is at least about 25 times more biased toward Gα signaling than it is toward β-repressor protein signaling. In some embodiments, the apralin receptor agonist is at least about 30 times more biased toward Gα signaling than it is toward β-repressor protein signaling. In some embodiments, the apralin receptor agonist is at least about 40 times more biased toward Gα signaling than it is toward β-repressor protein signaling. In some embodiments, the apralin receptor agonist is at least about 50 times more biased toward Gα signaling than it is toward β-repressor protein signaling. In some embodiments, the apralin receptor agonist is at least about 50 times more biased toward Gα signaling than it is toward β-repressor protein signaling. In some embodiments, the apralin receptor agonist is at least about 100 times more biased toward Gα signaling than it is toward β-repressor protein signaling. In some embodiments, the apralin receptor agonist is at least about 200 times more biased toward Gα signaling than it is toward β-repressor protein signaling.In some embodiments, the apralin receptor agonist is at least about 500 times more biased toward Gα signaling than toward β-repressor signaling.

[0172] In some embodiments, the G receptor agonist of apralinide αi Signal transduction assays showed EC50 values ​​less than 60 nM, as measured by cAMP depletion. In some embodiments, the G... αi Signal transduction assays showed EC50 values ​​less than 80 nM, as measured by cAMP depletion. In some embodiments, the G... αi Signal transduction assays showed EC50 values ​​less than 75 nM, as measured by cAMP depletion. In some embodiments, the G... αi Signal transduction assays showed EC50 values ​​less than 70 nM, as measured by cAMP depletion. In some embodiments, the G... αi Signal transduction assays showed EC50 values ​​less than 65 nM, as measured by cAMP depletion. In some embodiments, the G... αi Signal transduction assays showed EC50 values ​​less than 60 nM, as measured by cAMP depletion. In some embodiments, the G... αi Signal transduction assays showed EC50 values ​​less than 55 nM, as measured by cAMP depletion. In some embodiments, the G... αi Signal transduction assays showed EC50 values ​​less than 50 nM, as measured by cAMP depletion. In some embodiments, the G... αi Signal transduction assays showed EC50 values ​​less than 45 nM, as measured by cAMP depletion. In some embodiments, the G... αi Signal transduction assays showed EC50 values ​​less than 40 nM, as measured by cAMP depletion. In some embodiments, the G... αi Signal transduction assays showed EC50 values ​​less than 35 nM, as measured by cAMP depletion. In some embodiments, the G... αi Signal transduction assays showed EC50 values ​​less than 30 nM, as measured by cAMP depletion. In some embodiments, the G... αi Signal transduction assays showed EC50 values ​​less than 25 nM, as measured by cAMP depletion. In some embodiments, the G... αiSignal transduction assays showed EC50 values ​​less than 20 nM, as measured by cAMP depletion. In some embodiments, the G... αi Signal transduction assays showed EC50 values ​​less than 15 nM, as measured by cAMP depletion. In some embodiments, the G... αi Signal transduction assays showed EC50 values ​​less than 10 nM, as measured by cAMP depletion. In some embodiments, the G... αi Signal transduction assays showed EC50 values ​​less than 5 nM, as measured by cAMP depletion. In some embodiments, the G... αi Signal transduction assays showed EC50 values ​​less than 2 nM, as measured by cAMP depletion. In some embodiments, the G... αi Signal transduction measurements show EC50 values ​​less than 1 nM, such as those obtained by cAMP depletion.

[0173] In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is less than 1000 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is less than 600 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is less than 500 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is less than 450 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is less than 400 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is less than 350 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is less than 300 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is less than 250 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is less than 200 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is less than 150 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is less than 100 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is less than 80 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is less than 60 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is less than 50 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is less than 40 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is less than 30 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is less than 20 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is less than 10 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is less than 5 nM.

[0174] In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is greater than 5 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is greater than 10 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is greater than 20 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is greater than 30 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is greater than 40 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is greater than 50 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is greater than 60 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is greater than 70 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is greater than 80 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is greater than 90 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is greater than 100 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is greater than 200 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is greater than 300 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is greater than 400 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is greater than 500 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is greater than 600 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is greater than 700 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is greater than 800 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is greater than 900 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is greater than 1000 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is greater than 2000 nM. In some embodiments, the EC50 value of the β-repressor protein signal transduction assay of the apralin receptor agonist is greater than 5000 nM.

[0175] In some embodiments, the EC50 value of the ERK activation assay of the apralin receptor agonist is less than 50 nM. In some embodiments, the EC50 value of the ERK activation assay of the apralin receptor agonist is less than 40 nM. In some embodiments, the EC50 value of the ERK activation assay of the apralin receptor agonist is less than 30 nM. In some embodiments, the EC50 value of the ERK activation assay of the apralin receptor agonist is less than 25 nM. In some embodiments, the EC50 value of the ERK activation assay of the apralin receptor agonist is less than 20 nM. In some embodiments, the EC50 value of the ERK activation assay of the apralin receptor agonist is less than 15 nM. In some embodiments, the EC50 value of the ERK activation assay of the apralin receptor agonist is less than 10 nM. In some embodiments, the EC50 value of the ERK activation assay of the apralin receptor agonist is less than 5 nM. In some embodiments, the EC50 value of the ERK activation assay of the apralin receptor agonist is less than 2 nM. In some embodiments, the EC50 value of the ERK activation assay of the apralin receptor agonist is less than 1 nM.

[0176] half life In some embodiments, the apralin receptor agonist of the present invention exhibits higher efficacy and potency compared to wild-type or endogenous apralin or alabellatin. In some embodiments, the apralin receptor agonist of the present invention has an increased half-life compared to wild-type or endogenous apralin or alabellatin. In some embodiments, the apralin receptor agonist of the present invention is less susceptible to proteolytic cleavage compared to wild-type or endogenous apralin or alabellatin. In some embodiments, the apralin receptor agonist of the present invention is less susceptible to renal clearance compared to wild-type or endogenous apralin or alabellatin.

[0177] In some embodiments, the plasma or serum half-life of the apralin receptor agonist is at least about 30 minutes. In some embodiments, the plasma or serum half-life of the apralin receptor agonist is at least about 1 hour. In some embodiments, the plasma or serum half-life of the apralin receptor agonist is at least about 2 hours. In some embodiments, the plasma or serum half-life of the apralin receptor agonist is at least about 3 hours. In some embodiments, the plasma or serum half-life of the apralin receptor agonist is at least about 4 hours. In some embodiments, the plasma or serum half-life of the apralin receptor agonist is at least about 5 hours. In some embodiments, the plasma or serum half-life of the apralin receptor agonist is at least about 6 hours. In some embodiments, the plasma or serum half-life of the apralin receptor agonist is at least about 7 hours. In some embodiments, the plasma or serum half-life of the apralin receptor agonist is at least about 8 hours. In some embodiments, the plasma or serum half-life of the apralin receptor agonist is at least about 9 hours. In some embodiments, the plasma or serum half-life of the apralin receptor agonist is at least about 10 hours. In some embodiments, the plasma or serum half-life of the apralin receptor agonist is at least about 12 hours. In some embodiments, the plasma or serum half-life of the apralin receptor agonist is at least about 24 hours. In some embodiments, the plasma or serum half-life of the apralin receptor agonist is at least about 2 days. In some embodiments, the plasma or serum half-life of the apralin receptor agonist is at least about 3 days. In some embodiments, the plasma or serum half-life of the apralin receptor agonist is at least about 4 days. In some embodiments, the plasma or serum half-life of the apralin receptor agonist is at least about 5 days. In some embodiments, the plasma or serum half-life of the apralin receptor agonist is at least about 6 days. In some embodiments, the plasma or serum half-life of the apralin receptor agonist is at least about 7 days. In some embodiments, the plasma or serum half-life of the apralin receptor agonist is at least about 10 days. In some embodiments, the plasma or serum half-life of the apralin receptor agonist is at least about 15 days. In some embodiments, the plasma or serum half-life of the apralin receptor agonist is at least about two weeks. In some embodiments, the plasma or serum half-life of the apralin receptor agonist is at least about 3 weeks. In some embodiments, the plasma or serum half-life of the apralin receptor agonist is at least about 4 weeks.

[0178] In some embodiments, the half-life of the apralin receptor agonist is at least twice that of wild-type apralin or ilabellatide. In some embodiments, the half-life of the apralin receptor agonist is at least three times that of wild-type apralin or ilabellatide. In some embodiments, the half-life of the apralin receptor agonist is at least four times that of wild-type apralin or ilabellatide. In some embodiments, the half-life of the apralin receptor agonist is at least five times that of wild-type apralin or ilabellatide. In some embodiments, the half-life of the apralin receptor agonist is at least six times that of wild-type apralin or ilabellatide. In some embodiments, the half-life of the apralin receptor agonist is at least seven times that of wild-type apralin or ilabellatide. In some embodiments, the half-life of the apralin receptor agonist is at least eight times that of wild-type apralin or ilabellatide. In some embodiments, the half-life of the apralin receptor agonist is at least 9 times that of wild-type apralin or ilabellatide. In some embodiments, the half-life of the apralin receptor agonist is at least 10 times that of wild-type apralin or ilabellatide. In some embodiments, the half-life of the apralin receptor agonist is at least 11 times that of wild-type apralin or ilabellatide. In some embodiments, the half-life of the apralin receptor agonist is at least 12 times that of wild-type apralin or ilabellatide. In some embodiments, the half-life of the apralin receptor agonist is at least 15 times that of wild-type apralin or ilabellatide. In some embodiments, the half-life of the apralin receptor agonist is at least 20 times that of wild-type apralin or ilabellatide. In some embodiments, the half-life of the apralin receptor agonist is at least 25 times that of wild-type apralin or ilabellatide. In some embodiments, the half-life of the apralin receptor agonist is at least 30 times that of wild-type apralin or ilabellatide. In some embodiments, the half-life of the apralin receptor agonist is at least 40 times that of wild-type apralin or ilabellatide. In some embodiments, the half-life of the apralin receptor agonist is at least 50 times that of wild-type apralin or ilabellatide. In some embodiments, the half-life of the apralin receptor agonist is at least 100 times that of wild-type apralin or ilabellatide.

[0179] Desensitization GPCR desensitization is a multi-point problem that occurs across multiple stages. Generally, β-repressor protein signaling has been associated with desensitization, but these effects have not been extensively studied using APJ.

[0180] GPCR desensitization can occur in both short-term and long-term phases. In the short term, the receptor can be internalized into the endosome, thus removing it from the cell membrane and preventing its interaction with natural ligands or drugs. While the internalized receptor can sometimes be recycled back to the membrane and made usable again, in other cases the endosome will fuse with the lysosome and target the receptor for degradation, resulting in long-term desensitization.

[0181] In the long term, persistent signal transduction may lead to transcriptional downregulation of the receptor and its downstream effectors. This results in either receptor removal from the cell membrane or decoupling of receptor activation from downstream effector function, thereby further reducing the effectiveness of both natural ligands and drugs.

[0182] In some embodiments, the apralin receptor agonist of the present invention has reduced desensitization compared to wild-type or endogenous apralin or apralin.

[0183] In some embodiments, the reduced desensitization induced by apralin receptor agonists is at least 2 times lower than that induced by wild-type apralin or alabella peptide. In some embodiments, the reduced desensitization induced by apralin receptor agonists is at least 3 times lower than that induced by wild-type apralin or alabella peptide. In some embodiments, the reduced desensitization induced by apralin receptor agonists is at least 4 times lower than that induced by wild-type apralin or alabella peptide. In some embodiments, the reduced desensitization induced by apralin receptor agonists is at least 5 times lower than that induced by wild-type apralin or alabella peptide. In some embodiments, the reduced desensitization induced by apralin receptor agonists is at least 6 times lower than that induced by wild-type apralin or alabella peptide. In some embodiments, the reduced desensitization induced by apralin receptor agonists is at least 7 times lower than that induced by wild-type apralin or alabella peptide. In some embodiments, the reduced desensitization induced by apralin receptor agonists is at least 8 times lower than that induced by wild-type apralin or alabella peptide. In some embodiments, the reduced desensitization induced by apralin receptor agonists is at least 9 times lower than that induced by wild-type apralin or alabella peptide. In some embodiments, the reduced desensitization induced by apralin receptor agonists is at least 10 times lower than that induced by wild-type apralin or alabella peptide. In some embodiments, the reduced desensitization induced by apralin receptor agonists is at least 12 times lower than that induced by wild-type apralin or alabella peptide. In some embodiments, the reduced desensitization induced by apralin receptor agonists is at least 15 times lower than that induced by wild-type apralin or alabella peptide. In some embodiments, the reduced desensitization induced by apralin receptor agonists is at least 20 times lower than that induced by wild-type apralin or alabella peptide. In some embodiments, the reduced desensitization induced by apralin receptor agonists is at least 30 times lower than that induced by wild-type apralin or alabella peptide. In some embodiments, the reduced desensitization induced by apralin receptor agonists is at least 40 times lower than that induced by wild-type apralin or alabella peptide. In some embodiments, the reduced desensitization induced by apralin receptor agonists is at least 50 times lower than that induced by wild-type apralin or alabella peptide. In some embodiments, the reduced desensitization induced by apralin receptor agonists is at least 60 times lower than that induced by wild-type apralin or alabella peptide. In some embodiments, the reduced desensitization induced by apralin receptor agonists is at least 80 times lower than that induced by wild-type apralin or alabella peptide. In some embodiments, the reduced desensitization induced by apralin receptor agonists is at least 100 times lower than that induced by wild-type apralin or alabella peptide.

[0184] Internalization In some embodiments, the apralin peptide receptor agonist of the present invention has reduced internalization compared to wild-type or endogenous apralin peptide or ilaberlepeptide. In some embodiments, the apralin peptide receptor agonist of the present invention is substantially free of internalization. The reduced internalization rate of the apralin peptide receptor agonist compared to the wild-type ligand may be a desirable characteristic, as it allows for more efficient and sustained activation of the apralin peptide receptor and its downstream effects.

[0185] In some embodiments, the reduction in internalization of the apralin receptor agonist is at least 2-fold less than that of wild-type apralin or ilabella peptide. In some embodiments, the reduction in internalization of the apralin receptor agonist is at least 3-fold less than that of wild-type apralin or ilabella peptide. In some embodiments, the reduction in internalization of the apralin receptor agonist is at least 4-fold less than that of wild-type apralin or ilabella peptide. In some embodiments, the reduction in internalization of the apralin receptor agonist is at least 5-fold less than that of wild-type apralin or ilabella peptide. In some embodiments, the reduction in internalization of the apralin receptor agonist is at least 6-fold less than that of wild-type apralin or ilabella peptide. In some embodiments, the reduction in internalization of the apralin receptor agonist is at least 7-fold less than that of wild-type apralin or ilabella peptide. In some embodiments, the reduction in internalization of the apralin receptor agonist is at least 8-fold less than that of wild-type apralin or ilabella peptide. In some embodiments, the reduced internalization of the apralin receptor agonist is at least 9 times smaller than that of wild-type apralin or ilabella peptide. In some embodiments, the reduced internalization of the apralin receptor agonist is at least 10 times smaller than that of wild-type apralin or ilabella peptide.

[0186] In some embodiments, the internalization rate of the apralin receptor agonist is at least 2-fold lower than that of wild-type apralin or ilabella peptide. In some embodiments, the internalization rate of the apralin receptor agonist is at least 3-fold lower than that of wild-type apralin or ilabella peptide. In some embodiments, the internalization rate of the apralin receptor agonist is at least 4-fold lower than that of wild-type apralin or ilabella peptide. In some embodiments, the internalization rate of the apralin receptor agonist is at least 5-fold lower than that of wild-type apralin or ilabella peptide. In some embodiments, the internalization rate of the apralin receptor agonist is at least 6-fold lower than that of wild-type apralin or ilabella peptide. In some embodiments, the internalization rate of the apralin receptor agonist is at least 7-fold lower than that of wild-type apralin or ilabella peptide. In some embodiments, the internalization rate of the apralin receptor agonist is at least 8-fold lower than that of wild-type apralin or ilabella peptide. In some embodiments, the internalization rate of the apralin receptor agonist is at least 9 times lower than that of wild-type apralin or ilabella peptide. In some embodiments, the internalization rate of the apralin receptor agonist is at least 10 times lower than that of wild-type apralin or ilabella peptide.

[0187] In some embodiments, the apralin receptor agonist is not internalized. In some embodiments, the apralin receptor agonist is internalized only when it is present at a concentration greater than 1000 nM. In some embodiments, the apralin receptor agonist is internalized only when it is present at a concentration greater than 500 nM. In some embodiments, the apralin receptor agonist is internalized only when it is present at a concentration greater than 100 nM. In some embodiments, the apralin receptor agonist is internalized only when it is present at a concentration greater than 50 nM. In some embodiments, the apralin receptor agonist is internalized only when it is present at a concentration greater than 100 nM.

[0188] Treatment with apralin receptor agonists In particular, this invention provides a method for treating a disease by administering the ipalin peptide receptor agonist disclosed herein. In some embodiments, administration of the ipalin peptide receptor agonist of this invention improves, stabilizes, or alleviates one or more symptoms of the disease.

[0189] In some embodiments, the disease involves apralinide receptor signaling. In some embodiments, the disease is pulmonary hypertension (PAH). In some embodiments, the disease is systemic sclerosis (SSc). In some embodiments, the disease is heart failure with preserved ejection fraction (HfpEf). In some embodiments, the disease is age-related sarcopenia. In some embodiments, the disease is acute kidney injury (AKI). In some embodiments, the disease is cardiovascular disease. In some embodiments, the disease is cancer. In some embodiments, the disease is diabetes. In some embodiments, the disease is acute decompensated heart failure. In some embodiments, the disease is congestive heart failure. In some embodiments, the disease is myocardial infarction. In some embodiments, the disease is cardiomyopathy. In some embodiments, the disease is local ischemia. In some embodiments, the disease is local ischemia / reperfusion injury. In some embodiments, the disease is pulmonary hypertension. In some embodiments, the disease is obesity. In some embodiments, the disease is metastatic disease. In some embodiments, the disease is fluid homeostasis. In some embodiments, the disease is pathological angiogenesis. In some embodiments, the disease is retinopathy. In some embodiments, the disease is fibrosis. In some embodiments, the disease is HIV infection. In some embodiments, the disease is insulin resistance and type 2 diabetes. In some embodiments, the disease is other apralinide-related diseases.

[0190] The apralin peptide receptor agonist of the present invention (also referred to herein as the “active compound”) can be incorporated into pharmaceutical compositions suitable for administration. Such compositions typically comprise an apralin peptide receptor agonist and a pharmaceutically acceptable carrier. As used herein, the term “pharmaceutically acceptable carrier” is intended to include any and all solvents, dispersion media, coatings, antibacterial and antifungal agents, isotonic agents, and absorption delay agents compatible with pharmaceutical administration. Suitable carriers are described in the latest edition of Remington's Pharmaceutical Sciences, which is the standard reference text in the art and is incorporated herein by reference. Preferred examples of such carriers or diluents include, but are not limited to, water, saline, Ringer's solution, dextran solution, and 5% human serum albumin. Liposomes and non-aqueous media, such as fixed oils, may also be used. The use of such media and agents for pharmaceutically active substances is well known in the art. Their use in a composition should be considered unless any conventional media or agent is incompatible with the active compound. Additional active compounds may also be incorporated into the composition.

[0191] The pharmaceutical compositions of the present invention are formulated to be compatible with their intended route of administration. Examples of routes of administration include parenteral, such as intravenous, intradermal, subcutaneous, oral (e.g., inhalation), transdermal (i.e., topical), transmucosal, and rectal administration. Solutions or suspensions for parenteral, intradermal, or subcutaneous application may include the following components: sterile diluents, such as water for injection, saline solution, fixative oil, polyethylene glycol, glycerol, propylene glycol, or other synthetic solvents; antibacterial agents, such as benzyl alcohol or methylparaben; antioxidants, such as ascorbic acid or sodium bisulfite; chelating agents, such as ethylenediaminetetraacetic acid (EDTA); buffers, such as acetate, citrate, or phosphate; and agents for adjusting tension, such as sodium chloride or dextran. The pH may be adjusted with an acid or base, such as hydrochloric acid or sodium hydroxide. Parenteral formulations may be packaged in ampoules, disposable syringes, or multi-dose vials made of glass or plastic.

[0192] Suitable pharmaceutical compositions for injectable applications include sterile aqueous solutions (in the water-soluble case) or dispersions, as well as sterile powders for the ad hoc preparation of sterile injectable solutions or dispersions. For intravenous administration, suitable carriers include physiological saline, antibacterial water, polyoxyethylene castor oil (Cremophor EL)™ (BASF, Parsippany, NJ), or phosphate-buffered saline (PBS). The carrier can be a solvent or dispersion medium containing, for example, water, ethanol, polyols (e.g., glycerol, propylene glycol, and liquid polyethylene glycol), and suitable mixtures thereof. For example, by using a coating such as lecithin, the desired particle size can be maintained in the dispersed state, and by using surfactants, appropriate flowability can be maintained. Prevention of microbial action can be achieved by various antibacterial and antifungal agents, such as parabens, chlorobutanol, phenol, ascorbic acid, thimerosal, etc. In many cases, it is preferred to include isotonic agents, such as sugars, polyols such as mannitol, sorbitol, and sodium chloride. Prolonged absorption of injectable compositions can be achieved by including agents that delay absorption, such as aluminum monostearate and gelatin, in the composition.

[0193] Sterile injectable solutions can be prepared by incorporating the desired amount of active compound into a suitable solvent, which, as needed, contains one or a combination of the components listed above, followed by filtration sterilization. Typically, dispersions are prepared by incorporating the active compound into a sterile medium containing a basic dispersion medium and other desired components from the components listed above. In the case of sterile powders used to prepare sterile injectable solutions, the preparation method involves vacuum drying and freeze-drying of a powder containing the active ingredient plus any other desired components from its previous sterile-filtered solution.

[0194] Oral compositions typically include an inert diluent or an edible carrier. They may be encapsulated in gelatin capsules or compressed into tablets. For oral therapeutic administration, the active compound may be incorporated with excipients and used in tablet, lozenge, or capsule form. Oral compositions may also be prepared using a fluid carrier used as a mouthwash, wherein the compound in the fluid carrier is administered orally and rinsed and spat out or swallowed. Pharmaceutically compatible binders and / or adjuvants may be included as part of the composition. Tablets, pills, capsules, lozenges, etc., may contain any of the following components or compounds with similar properties: binders, such as microcrystalline cellulose, tragacanth gum, or gelatin; excipients, such as starch or lactose; disintegrants, such as alginate, primogel, or corn starch; lubricants, such as magnesium stearate or sterotes; flow aids, such as colloidal silica; sweeteners, such as sucrose or saccharin; or flavorings, such as peppermint, methyl salicylate, or orange flavorings.

[0195] For administration by inhalation, the compound is delivered as an aerosol spray from a pressure vessel or dispenser containing a suitable propellant, such as a gas like carbon dioxide, or from a sprayer.

[0196] Systemic application can also be performed transmucosal or transdermal. For transmucosal or transdermal application, a penetrant suitable for the barrier to be penetrated is used in the formulation. Such penetrants are generally known in the art and, for example, for transmucosal application, include cleansers, bile salts, and clostridial acid derivatives. Transmucosal application can be achieved by using nasal sprays or suppositories. For transdermal application, as is generally known in the art, the active compound is formulated as an ointment, cream, gel, or lotion.

[0197] The compound can also be formulated as a suppository (e.g., using conventional suppository bases such as cocoa butter and other glycerides) or a retention enema for rectal delivery.

[0198] In one embodiment, the active compound is prepared together with a carrier that protects the compound from rapid elimination from the body, such as controlled-release formulations, including implants and microencapsulated delivery systems. Biodegradable, biocompatible polymers such as ethylene vinyl acetate, polyanhydride, polyglycolic acid, collagen, polyorthoesters, and polylactic acid can be used. Methods for preparing such formulations will be readily apparent to those skilled in the art. Materials are also commercially available from Alza Corporation and Nova Pharmaceuticals, Inc. Liposome suspensions (including liposomes containing monoclonal antibodies against viral antigens that target infected cells) can also be used as pharmaceutically acceptable carriers. These can be prepared according to methods known to those skilled in the art, for example, as described in U.S. Patent No. 4,522,811.

[0199] Particularly advantageous is the formulation of oral or parenteral compositions in dose units for ease of administration and dosage uniformity. As used herein, dose units refer to physically discrete units suitable as a unit dose for a subject to be treated; each unit contains a predetermined amount of active compound calculated to bind with the desired drug carrier to produce the desired therapeutic effect. The specifications of the dose units of this invention are controlled by and directly depend on the unique properties of the active compound and the specific therapeutic effect to be achieved, as well as the inherent limitations in the field of compounding such active compounds for individualized treatment.

[0200] The pharmaceutical composition may be included in a container, package, or dispenser along with the instructions for use.

[0201] The present invention also includes the following embodiments: Implementation Method 1. An apelin receptor agonist comprising an apelin peptide analog, wherein the apelin peptide analog comprises one or more amino acid substitutions relative to SEQ ID NO: 1 (QRPRLSHKGPMPF). The one or more amino acid substitutions occur at positions 1, 6, 8, 9, 11, 12 and / or 13.

[0202] Implementation Method 2. The apralin peptide receptor agonist according to Implementation Method 1, wherein one or more amino acid substitutions comprise P12V, K8W, Q1E, M11H, M11A, F13Y, P12A, P12H, F13W, S6Q and / or G9N.

[0203] Embodiment 3. An apralin peptide receptor agonist comprising an apralin peptide analog, wherein the apralin peptide analog comprises the following amino sequence: X1-RPRLSH-X2-GP-X3-X4-X5 in X1 is either Q or E; X2 is either K or W; X3 is M, H, or A; X4 is P, V, A, or H; and / or X5 can be F, Y, or W.

[0204] Embodiment 4. An apralin peptide receptor agonist comprising an apralin peptide analog, wherein the apralin peptide analog comprises the following amino sequence: QRPRLQHKNPMA-X1 in X1 is either F or W.

[0205] Embodiment 5. An apralin peptide receptor agonist comprising an apralin peptide analog, wherein the apralin peptide analog comprises the following amino sequence: QRPRLSHKGP-X1-X2-X3 in X1 is M, H, or A; X2 is P, V, A, or H; and / or X3 can be F, Y, or W.

[0206] Embodiment 6. An apralin peptide receptor agonist comprising an apralin peptide analog, wherein the apralin peptide analog comprises the following amino sequence: X1-RPRL-X2-H-X3-X4-P-X5-X6-X7 in X1 is either Q or E; X2 is either S or Q; X3 is either K or W; X4 is either G or N; X5 is M, H, or A; X6 is P, V, A, or H; and / or X7 can be F, Y, or W.

[0207] Embodiment 7. An apralin peptide receptor agonist according to Embodiment 3 or 5, wherein the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 1 (QRPRLSHKGPMPF).

[0208] Embodiment 8. An apralin peptide receptor agonist according to Embodiment 3 or 5, wherein the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 2 (QRPRLSHKGPMVF).

[0209] Embodiment 9. An apralin peptide receptor agonist according to Embodiment 3, wherein the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 3 (QRPRLSHWGPMPF).

[0210] Embodiment 10. An apralin peptide receptor agonist according to Embodiment 3, wherein the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 4 (ERPRLSHKGPMPF).

[0211] Implementation Method 11. An apralin peptide receptor agonist according to Implementation Method 3 or 5, wherein the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 5 (QRPRLSHKGPHPF).

[0212] Embodiment 12. An apralin peptide receptor agonist according to Embodiment 3 or 5, wherein the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 6 (QRPRLSHKGPAPY).

[0213] Embodiment 13. An apralin peptide receptor agonist according to Embodiment 3 or 5, wherein the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 7 (QRPRLSHKGPMAF).

[0214] Embodiment 14. An apralin peptide receptor agonist according to Embodiment 3 or 5, wherein the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 50 (QRPRLSHKGPMHW).

[0215] Embodiment 15. An apralin peptide receptor agonist according to Embodiment 3 or 5, wherein the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 51 (QRPRLSHKGPAAW).

[0216] Embodiment 16. An apralin peptide receptor agonist according to Embodiment 3 or 5, wherein the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 52 (QRPRLSHKGPAAY).

[0217] Embodiment 17. An apralin peptide receptor agonist according to Embodiment 3, wherein the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 55 (QRPRLSHWGPMAW).

[0218] Embodiment 18. An apralin peptide receptor agonist according to Embodiment 4, wherein the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 53 (QRPRLQHKNPMAF).

[0219] Embodiment 19. An apralin peptide receptor agonist according to Embodiment 4, wherein the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 54 (QRPRLQHKNPMAW).

[0220] Implementation Method 20. An elabella peptide receptor agonist comprising an elabella peptide analogue, wherein the elabella peptide analogue comprises one or more amino acid substitutions relative to SEQ ID NO: 8 (KLRKHNCLQRRCMPLHSRVPFP). The one or more amino acid substitutions occur at positions 3, 7, 8, 9, 10, 12, 14, 15, 17 and / or 18.

[0221] Embodiment 21. The apralin peptide receptor agonist according to Embodiment 20, wherein one or more amino acid substitutions comprise R3N, P14I, S17Q, S17R, Q9K, R18Y, L15Y, C7S, C12Y, R10E, Q9I, L8A and / or Q9T.

[0222] Implementation Method 22. An apralin peptide receptor agonist comprising an alabellatin analogue, wherein the alabellatin analogue comprises the following amino sequence: KL-Z1-KHN-Z2-Z3-Z4-Z5-R-Z6-M-Z7-Z8-H-Z9-Z10-VPFP in Z1 is either R or N; Z2 is either C or S; Z3 is either A or L; Z4 is Q, I, K, or T; Z5 is either R or E; Z6 is either C or Y; Z7 is either P or I; Z8 is either L or Y; Z9 is S, Q, or R; and / or Z10 is either R or Y.

[0223] Example 23. The alabera peptide receptor agonist according to Example 22, wherein the alabera peptide analog comprises the amino acid sequence of SEQ ID NO: 8 (KLRKHNCLQRRCMPLHSRVPFP).

[0224] Example 24. The alabera peptide receptor agonist according to Example 22, wherein the alabera peptide analog comprises the amino acid sequence of SEQ ID NO: 9 (KLNKHNCLQRRCMPLHSRVPFP).

[0225] Example 25. The alabera peptide receptor agonist according to Example 22, wherein the alabera peptide analog comprises the amino acid sequence of SEQ ID NO: 10 (KLRKHNCLQRRCMILHSRVPFP).

[0226] Example 26. The alabera peptide receptor agonist according to Example 22, wherein the alabera peptide analog comprises the amino acid sequence of SEQ ID NO: 11 (KLRKHNCLQRRCMPLHQRVPFP).

[0227] Example 27. The alabera peptide receptor agonist according to Example 22, wherein the alabera peptide analog comprises the amino acid sequence of SEQ ID NO: 12 (KLRKHNCLQRRCMPLHRRVPFP).

[0228] Example 28. The alabera peptide receptor agonist according to Example 22, wherein the alabera peptide analog comprises the amino acid sequence of SEQ ID NO: 13 (KLRKHNCLKRRCMPLHSRVPFP).

[0229] Example 29. The alabera peptide receptor agonist according to Example 22, wherein the alabera peptide analog comprises the amino acid sequence of SEQ ID NO: 30 (KLRKHNCLQRRCMPLHSYVPFP).

[0230] Example 30. The alabera peptide receptor agonist according to Example 22, wherein the alabera peptide analog comprises the amino acid sequence of SEQ ID NO: 31 (KLRKHNCLQRRCMPYHSRVPFP).

[0231] Embodiment 31. The alabera peptide receptor agonist according to Embodiment 22, wherein the alabera peptide analog comprises the amino acid sequence of SEQ ID NO: 32 (KLRKHNSLQRRYMPLHSRVPFP).

[0232] Embodiment 32. The alabera peptide receptor agonist according to Embodiment 22, wherein the alabera peptide analog comprises the amino acid sequence of SEQ ID NO: 33 (KLRKHNCLQERCMPLHSRVPFP).

[0233] Embodiment 33. The alabera peptide receptor agonist according to Embodiment 22, wherein the alabera peptide analog comprises the amino acid sequence of SEQ ID NO: 34 (KLRKHNCLIRRCMPLHSRVPFP).

[0234] Embodiment 34. The alabera peptide receptor agonist according to Embodiment 22, wherein the alabera peptide analog comprises the amino acid sequence of SEQ ID NO: 35 (KLRKHNCATRRCMPLHSRVPFP).

[0235] Embodiment 35. An apralin peptide receptor agonist according to any one of the foregoing embodiments, wherein the apralin peptide analog or the alabera peptide analog is fused to a carrier portion.

[0236] Embodiment 36. An apralin peptide receptor agonist according to Embodiment 35, wherein the N-terminus of the apralin peptide analog or the alaberapeptide analog is fused to the carrier portion.

[0237] Embodiment 37. An apralin receptor agonist according to Embodiment 35 or 36, wherein the carrier portion prolongs the half-life of the apralin receptor agonist.

[0238] Embodiment 38. An apralin peptide receptor agonist according to any one of Embodiments 35 to 37, wherein the carrier portion comprises an Fc domain, human serum albumin (HSA), an anti-HSA antibody or a fragment thereof, lipids or PEG.

[0239] Implementation Method 39. The apralin peptide receptor agonist according to Implementation Method 38, wherein the Fc domain is a monovalent Fc.

[0240] Implementation Method 40. The apralin peptide receptor agonist according to Implementation Method 38, wherein the Fc domain is a divalent Fc.

[0241] Implementation Method 41. The apralin peptide receptor agonist according to Implementation Method 38, wherein the anti-HSA antibody or fragment thereof is an anti-HSA Fab, nanobody (VHH), scFv, or V-NAR.

[0242] Embodiment 42. The apralin peptide receptor agonist according to Embodiment 41, wherein the anti-HSA VHH comprises ALB-23.

[0243] Implementation 43. An apralin receptor agonist comprising an apralin analog or an alabera peptide analog, wherein the N-terminus of the apralin analog or the alabera peptide analog is fused to a carrier portion via a linker.

[0244] Embodiment 44. An apralin peptide receptor agonist according to Embodiment 43, wherein the N-terminus of the apralin peptide analog or the alaberapeptide analog is fused to the C-terminus of the carrier portion.

[0245] Embodiment 45. An apralin receptor agonist according to Embodiment 43 or 44, wherein the carrier portion prolongs the half-life of the apralin receptor agonist.

[0246] Embodiment 46. An apralin peptide receptor agonist according to any one of Embodiments 43 to 45, wherein the carrier portion comprises an Fc domain, human serum albumin (HSA), an anti-HSA antibody or a fragment thereof, lipids or PEG.

[0247] Implementation Method 47. The apralin peptide receptor agonist according to Implementation Method 46, wherein the Fc domain is a monovalent Fc.

[0248] Implementation Method 48. The apralin peptide receptor agonist according to Implementation Method 46, wherein the Fc domain is a divalent Fc.

[0249] Embodiment 49. An apralin peptide receptor agonist according to any one of Embodiments 46 to 48, wherein the Fc domain is an IgG1, IgG2, IgG3 or IgG4 isotype.

[0250] Implementation Method 50. The apalin peptide receptor agonist according to Implementation Method 49, wherein the Fc domain is a human IgG1 monovalent Fc.

[0251] Implementation Method 51. The apalin peptide receptor agonist according to Implementation Method 49, wherein the Fc domain is human IgG1 bivalent Fc.

[0252] Implementation 52. The apalin peptide receptor agonist according to Implementation 49, wherein the Fc domain is a human IgG4 monovalent Fc containing the S228P mutation.

[0253] Embodiment 53. An apralin peptide receptor agonist according to any one of Embodiments 46 to 52, wherein the Fc domain contains one or more mutations compared to the wild-type Fc domain.

[0254] Embodiment 54. The apralin peptide receptor agonist according to Embodiment 53, wherein the Fc domain comprises SEQ ID NO: 14 or SEQ ID NO: 15.

[0255] Implementation 55. An apralin peptide receptor agonist according to Implementation 46, wherein the anti-HSA antibody or a fragment thereof is an anti-HSA Fab, a nanobody (VHH), scFv, or V-NAR.

[0256] Embodiment 56. The apralin peptide receptor agonist according to Embodiment 55, wherein the anti-HAS VHH comprises ALB-23.

[0257] Embodiment 57. An apralin peptide receptor agonist according to any one of Embodiments 43 to 56, wherein the linker comprises GGGGSGGGGSGGGGS (SEQ ID NO: 16).

[0258] Implementation Method 58. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 17.

[0259] Embodiment 59. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 18.

[0260] Embodiment 60. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 19.

[0261] Embodiment 61. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 20.

[0262] Embodiment 62. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 21.

[0263] Embodiment 63. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 22.

[0264] Embodiment 64. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 23.

[0265] Embodiment 65. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 24.

[0266] Implementation 66. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 25.

[0267] Implementation 67. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 26.

[0268] Embodiment 68. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 27.

[0269] Embodiment 69. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 28.

[0270] Implementation Method 70. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 29.

[0271] Implementation Method 71. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 36.

[0272] Implementation Method 72. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 37.

[0273] Embodiment 73. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 38.

[0274] Embodiment 74. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 39.

[0275] Implementation Method 75. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 40.

[0276] Implementation Method 76. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 41.

[0277] Implementation Method 77. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 56.

[0278] Implementation Method 78. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 57.

[0279] Implementation Method 79. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 58.

[0280] Implementation Method 80. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 59.

[0281] Implementation Method 81. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 60.

[0282] Embodiment 82. An apralin peptide receptor agonist according to any one of the foregoing embodiments, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, and 99% of the same amino acid sequence as SEQ ID NO: 61.

[0283] Embodiment 83. An apralin peptide receptor agonist according to any one of the foregoing embodiments, wherein the G of the apralin peptide receptor agonist is... αi Signal transduction measurements of EC50 values ​​less than 60 nM, less than 30 nM, less than 20 nM, or less than 10 nM, such as those obtained by cAMP depletion.

[0284] Implementation Method 84. An apralin peptide receptor agonist according to any one of the foregoing embodiments, wherein the EC50 value of the apralin peptide receptor agonist as determined by β-inhibitory protein signal transduction is less than 1000 nM, 600 nM, less than 500 nM, less than 100 nM, less than 30 nM, or less than 10 nM.

[0285] Implementation Method 85. An apralin peptide receptor agonist according to any one of the foregoing embodiments, wherein the apralin peptide receptor agonist has an ERK activation assay EC50 value of less than 20 nM, less than 10 nM, less than 5 nM, less than 2 nM, or less than 1 nM.

[0286] Implementation Method 86. A method of treating a disease, the method comprising administering an apralin receptor agonist according to any one of the foregoing embodiments to a subject in need.

[0287] Implementation 87. The method according to implementation 86, wherein the disease is pulmonary hypertension (PAH), systemic sclerosis (SSc), heart failure with preserved ejection fraction (HfpEf), age-related sarcopenia, or acute kidney injury (AKI).

[0288] Embodiment 88. A nucleic acid encoding an apralin receptor agonist according to any one of Embodiments 1 to 82 above.

[0289] Embodiment 89. A method for producing an apralin receptor agonist according to any one of Embodiments 1 to 82 above.

[0290] Example While certain compounds, compositions, and methods of this disclosure have been specifically described with reference to certain embodiments, the following examples are for illustrative purposes only and are not intended to limit the scope of this disclosure.

[0291] Example 1—The effect of apralin receptor agonists on the apralin receptor signaling pathway This embodiment measures the effects of the apralin receptor agonist of the present invention on various downstream signaling pathways of the apralin receptor system.

[0292] Apalin peptide receptor and pertussis toxin-sensitive inhibitory G protein (Gα) i / o This couples with, subsequently activating the extracellular regulated kinase (ERK) signaling cascade ( Figure 1 These cascades lead to a wide range of physiological effects, depending on the type of cell activated. All putative apralin peptides and ELA isoforms cause conventional Gi-mediated inhibition of adenylate cyclase, which leads to cAMP inhibition. Signaling via β-repressor protein leads to apralin peptide receptor desensitization and internalization. The internalized receptor is targeted for degradation or recycled to the cell surface. β-repressor protein-mediated signaling may also contribute to the action of apralin peptides.

[0293] In this example, the commercially available HitHunter® cAMP assay was used to determine the effect of the apralin peptide receptor agonist on G. ai The effects of apralin receptor agonists on β-repressor signaling were investigated. Next, the commercially available PathHunter® β-repressor assay was used to determine the effects of apralin receptor agonists on β-repressor signaling. Additionally, the effects of apralin receptor agonists on ERK signaling were determined.

[0294] cAMP signal transduction measurement In 384-well plates (Corning #3897), cAMP Hunter™ CHO-K1 AGTRL1 Gi cells (Eurofins DiscoverX #95-0147C2) were seeded at 1 x 10⁴ cells / well in 20 μL LAssayComplete Cell Plating Reagent 2 (Eurofins DiscoverX #93-0563R2A) and incubated overnight at 37°C with 5% CO₂. The next day, the plated cells were washed with assay buffer (1X HBSS + 10 mM HEPES) and 20 μL / well of two-part assay buffer and one-part cAMP antibody from the HitHunter® cAMP Small Molecule Assay Kit (Eurofins DiscoverX #90-0075SM25) were added. The plate was treated with 5 μL / well of compound serially diluted in assay buffer + 15 μM Forskolin (Millipore Sigma #F6886) and incubated at 37°C with 5% CO2 for 30 min. Then, 20 μL / well of the assay solution, prepared according to the instructions in the HitHunter® cAMP Small Molecule Kit assay, was added, the plate was wrapped in foil, and incubated at room temperature for 1 h. Next, 20 μL / well of solution A from the HitHunter® cAMP Small Molecule Kit assay was added, and the plate was incubated overnight in foil at room temperature. The plate was read after approximately 18 hours of incubation on a standard luminescent plate reader. In this assay, due to the use of forskolin, the agonist activity is inhibitory, therefore low luminescence signal is directly correlated with high cAMP activity. Curve fitting was performed using four-parameter logistic regression to process the raw data file into a Z-shaped dose-response curve, from which values ​​such as EC50, Hill slope, and Emax were quantified.

[0295] β-inhibitory protein signal transduction assay In 384-well plates (Corning #3897), PathHunter® CHO-K1 AGTRL1 β-repressor cells (Eurotin DiscoverX #93-0250C2) were seeded at 5 x 10³ cells / well in 20 μL of AssayComplete Cell Plating 2 reagent (Eurotin DiscoverX #93-0563R2A) and incubated overnight at 37°C with 5% CO2. The next day, the plates were treated with 5 μL / well of compound serially diluted in 1X PBS + 0.1% BSA buffer and incubated at 37°C with 5% CO2 for 1.5 h. Then, 12.5 μL / well of the detection solution was added, prepared according to the instructions in the PathHunter® Assay Kit (Eurotin DiscoverX #93-0001), the plates were wrapped in foil, and incubated at room temperature. The plates were read after incubation for 1–2 hours on a standard luminescent plate reader. In this assay, low levels of β-repressor protein in cells were directly correlated with low luminescence signal. Curve fitting was performed using four-parameter logistic regression to process the raw data file into an S-shaped dose-response curve, from which values ​​such as EC50, Hill slope, and Emax were quantified.

[0296] Table 4 summarizes the EC50 values ​​determined from the three determinations explained above. The use of mass spectrometry to detect proteolytic activity during production provides insights into the proteolytic stability of the apralin peptide receptor agonist.

[0297] Table 4—Summary of EC50 values Example 2—Measurement results of desensitization using apralin receptor agonists Prolonged apralinide receptor signaling can lead to transcriptional downregulation of the receptor and its downstream effectors. This results in either receptor removal from the cell membrane or decoupling of receptor activation from downstream effector function, thereby again reducing the effectiveness of both the natural ligand and the drug. This invention particularly provides superior apralinide receptor agonists with reduced desensitization, offering improved efficacy and potency.

[0298] The degree of desensitization induced by the natural ligand and apralin peptide receptor agonist of the present invention was assessed by the following assays: 1. To measure the efficacy and effectiveness of β-repressor protein signaling.

[0299] 2. Microscopy was used to measure and track the localization of the apralin receptor in order to quantify the degree of receptor internalization that occurred after treatment.

[0300] 3. RT-PCR was used to measure the transcriptional downregulation levels of the apalaline peptide receptor and selected downstream signaling molecules.

[0301] 4. Repeat treatment and measurement of apralin peptide receptor agonists in in vitro and in vivo assays to see if the same response magnitude is obtained in subsequent measurements.

[0302] Example 3—Internalization of Apalin peptide receptor agonists In this example, the internalization of exemplary apralin receptor agonists was evaluated. CHO-M1 cells expressing the APJ-eGFP fusion protein were stained and plated in 96-well plates. Apralin receptor agonists were serially diluted and added to the wells at concentrations ranging from 0.914 nM to 2000 nM. Cell imaging was then performed using the Operetta CLS™ high-content analysis system. APJ-eGFP signaling was measured in both the membrane and cytoplasmic regions, and the ratio of membrane signal to total signal (E ratio) was calculated. Internalization scores were assigned based on the lowest concentration of the compound observed to have the highest internalization. Scores were assigned according to Table 5, and the internalization scores are summarized in Table 6. The internalization score for each apralin receptor agonist was plotted against the EC50 values ​​of cAMP signaling and β-repressor protein signaling, as shown in Table 6. Figure 2 and Figure 3 As shown.

[0303] Table 5—Internalization Scores Table 6—Internalization scores of exemplary ipalin peptide receptor agonists

Claims

1. An apelin receptor agonist comprising an apelin peptide analogue, wherein the apelin peptide analogue comprises one or more amino acid substitutions relative to SEQ ID NO: 1 (QRPRLSHKGPMPF), The one or more amino acid substitutions occur at positions 1, 6, 8, 9, 11, 12 and / or 13.

2. The apalin peptide receptor agonist according to claim 1, wherein one or more amino acid substitutions comprise P12V, K8W, Q1E, M11H, M11A, F13Y, P12A, P12H, F13W, S6Q and / or G9N.

3. The apralin peptide receptor agonist according to claim 1 or 2, wherein the apralin peptide analog comprises the following amino acid sequence: (a)X1-RPRLSH-X2-GP-X3-X4-X5 in X1 is either Q or E; X2 is either K or W; X3 is M, H, or A; X4 is P, V, A, or H; and / or X5 can be F, Y, or W; (b) QRPRLQHKNPMA-X1 in X1 is either F or W; (c)QRPRLSHKGP-X1-X2-X3 in X1 is M, H, or A; X2 is P, V, A, or H; and / or X3 is F, Y, or W; or (d)X1-RPRL-X2-H-X3-X4-P-X5-X6-X7 in X1 is either Q or E; X2 is either S or Q; X3 is either K or W; X4 is either G or N; X5 is M, H, or A; X6 is P, V, A, or H; and / or X7 can be F, Y, or W.

4. The apralin peptide receptor agonist according to any one of the preceding claims, wherein the apralin peptide analog comprises one of the following amino acid sequences: SEQ ID NO: 6 (QRPRLSHKGPAPY), SEQ ID NO: 50 (QRPRLSHKGPMHW), SEQ ID NO: 55 (QRPRLSHWGPMAW), SEQ ID NO: 1 (QRPRLSHKGPMPF), SEQ ID NO: 2 (QRPRLSHKGPMVF), SEQ ID NO: 3 (QRPRLSHWGPMPF), SEQ ID NO: 5 (QRPRLSHKGPHPF), SEQ ID NO: 7 (QRPRLSHKGPMAF), SEQ ID NO: 51 (QRPRLSHKGPAAW), SEQ ID NO: 52 (QRPRLSHKGPAAY), SEQ ID NO: 53 (QRPRLQHKNPMAF), and SEQ ID NO: 54 (QRPRLQHKNPMAW).

5. The apralin peptide receptor agonist according to any one of the preceding claims, wherein the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 6 (QRPRLSHKGPAPY).

6. The apralin peptide receptor agonist according to any one of the preceding claims, wherein the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 50 (QRPRLSHKGPMHW).

7. The apralin peptide receptor agonist according to any one of the preceding claims, wherein the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 55 (QRPRLSHWGPMAW).

8. The apralin peptide receptor agonist according to any one of the preceding claims, wherein the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 53 (QRPRLQHKNPMAF).

9. The apralin peptide receptor agonist according to any one of the preceding claims, wherein the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 3 (QRPRLSHWGPMPF).

10. The apralin peptide receptor agonist according to any one of the preceding claims, wherein the apralin peptide analog comprises the amino acid sequence of SEQ ID NO: 54 (QRPRLQHKNPMAW).

11. An elabella peptide receptor agonist comprising an elabella peptide analogue, wherein the elabella peptide analogue comprises one or more amino acid substitutions relative to SEQ ID NO: 8 (KLRKHNCLQRRCMPLHSRVPFP). The one or more amino acid substitutions occur at positions 3, 7, 8, 9, 10, 12, 14, 15, 17 and / or 18.

12. The apralin peptide receptor agonist of claim 11, wherein one or more amino acid substitutions comprise R3N, P14I, S17Q, S17R, Q9K, R18Y, L15Y, C7S, C12Y, R10E, Q9I, L8A and / or Q9T.

13. The alabeleneptide receptor agonist according to claim 11 or 12, wherein the alabeleneptide analog comprises the following amino acid sequence: KL-Z1-KHN-Z2-Z3-Z4-Z5-R-Z6-M-Z7-Z8-H-Z9-Z10-VPFP in Z1 is either R or N; Z2 is either C or S; Z3 is either A or L; Z4 is Q, I, K, or T; Z5 is either R or E; Z6 is either C or Y; Z7 is either P or I; Z8 is either L or Y; Z9 is S, Q, or R; and / or Z10 is either R or Y.

14. The alabelepeptide receptor agonist of claim 13, wherein the alabelepeptide analog comprises one of the following amino acid sequences: SEQ ID NO: 11 (KLRKHNCLQRRCMPLHQRVPFP), SEQ ID NO: 12 (KLRKHNCLQRRCMPLHRRVPFP), SEQ ID NO: 35 (KLRKHNCATRRCMPLHSRVPFP), SEQ ID NO: 8 (KLRKHNCLQRRCMPLHSRVPFP), SEQ ID NO: 9 (KLNKHNCLQRRCMPLHSRVPFP), SEQ ID NO: 10 (KLRKHNCLQRRCMILHSRVPFP), SEQ ID NO: 13 (KLRKHNCLKRRCMPLHSRVPFP), SEQ ID NO: 30 (KLRKHNCLQRRCMPLHSYVPFP), SEQ ID NO: 31 (KLRKHNCLQRRCMPYHSRVPFP), SEQ ID NO: 32 (KLRKHNSLQRRYMPLHSRVPFP), SEQ ID NO: 33 (KLRKHNCLQERCMPLHSRVPFP) and SEQ ID NO: 34 (KLRKHNCLIRRCMPLHSRVPFP).

15. The alabera peptide receptor agonist of claim 13, wherein the alabera peptide analog comprises the amino acid sequence of SEQ ID NO: 35 (KLRKHNCATRRCMPLHSRVPFP).

16. The alabera peptide receptor agonist of claim 13, wherein the alabera peptide analog comprises the amino acid sequence of SEQ ID NO: 11 (KLRKHNCLQRRCMPLHQRVPFP).

17. The alabera peptide receptor agonist of claim 13, wherein the alabera peptide analog comprises the amino acid sequence of SEQ ID NO: 12 (KLRKHNCLQRRCMPLHRRVPFP).

18. The alabelepeptide receptor agonist of claim 13, wherein the alabelepeptide analog comprises the amino acid sequence of SEQ ID NO: 31 (KLRKHNCLQRRCMPYHSRVPFP).

19. The alabera peptide receptor agonist of claim 13, wherein the alabera peptide analog comprises the amino acid sequence of SEQ ID NO: 34 (KLRKHNCLIRRCMPLHSRVPFP).

20. The alabera peptide receptor agonist of claim 13, wherein the alabera peptide analog comprises the amino acid sequence of SEQ ID NO: 8 (KLRKHNCLQRRCMPLHSRVPFP).

21. The apralin peptide receptor agonist according to any one of the preceding claims, wherein the apralin peptide analog or optionally the alabera peptide analog is fused to a carrier portion, optionally the N-terminus of the apralin peptide analog or the alabera peptide analog is fused to the carrier portion, optionally the carrier portion prolongs the half-life of the apralin peptide receptor agonist.

22. The apralin peptide receptor agonist of claim 21, wherein the carrier portion comprises an Fc domain, human serum albumin (HSA), an anti-HSA antibody or a fragment thereof, lipids or PEG; optionally, wherein a. The Fc structural domain is a monovalent Fc or a divalent Fc; b. The anti-HSA antibody or its fragment is an anti-HSA Fab, nanobody (VHH), scFv, or V-NAR, optionally wherein the anti-HSA VHH comprises ALB-23.

23. An apralin receptor agonist comprising an apralin analog or an alabera peptide analog, wherein the N-terminus of the apralin analog or the alabera peptide analog is fused to a carrier portion via a linker.

24. The apalin peptide receptor agonist of claim 23, wherein the N-terminus of the apalin peptide analog or the ilaberapeptide analog is fused to the C-terminus of the carrier portion, optionally wherein the carrier portion prolongs the half-life of the apalin peptide receptor agonist, and / or the carrier portion comprises an Fc domain, human serum albumin (HSA), an anti-HSA antibody or a fragment thereof, lipids or PEG.

25. The apalynide receptor agonist according to claim 24, wherein: a. The Fc domain is a monovalent Fc or a divalent Fc; and / or b. The Fc domain is an isotype of IgG1, IgG2, IgG3, or IgG4; and / or c. Compared to the wild-type Fc domain, the Fc domain contains one or more mutations; optionally, wherein: i. The Fc domain is a human IgG1 monovalent Fc, a human IgG1 bivalent Fc, or a human IgG4 monovalent Fc containing the S228P mutation; or ii. The Fc domain contains SEQ ID NO: 14 or SEQ ID NO:

15.

26. The apralin peptide receptor agonist of claim 24, wherein the anti-HSA antibody or a fragment thereof is an anti-HSA Fab, a nanobody (VHH), scFv, or V-NAR, optionally wherein the anti-HAS VHH comprises ALB-23.

27. The apralin peptide receptor agonist according to any one of claims 23 to 26, wherein the linker comprises GGGGSGGGGSGGGGS (SEQ ID NO: 16).

28. The apralin peptide receptor agonist according to any one of the preceding claims, comprising at least 80%, 85%, 90%, 93%, 95%, 98%, or 99% of the same amino acid sequence as one of SEQ ID NO:17-29, 36-41, and 56-61.

29. The apralinide receptor agonist according to any one of the preceding claims, wherein the apralinide receptor agonist comprises: a. G αi Signal transduction measurements with EC50 values ​​less than 60 nM, less than 30 nM, less than 20 nM, or less than 10 nM, such as those obtained by cAMP depletion; b. β-inhibitory protein signal transduction assays showing EC50 values ​​less than 1000 nM, 600 nM, less than 500 nM, less than 100 nM, less than 30 nM, or less than 10 nM; and / or c. ERK activation assay EC50 values ​​less than 20 nM, less than 10 nM, less than 5 nM, less than 2 nM, or less than 1 nM.

30. A method of treating a subject with a disease using an apralin receptor agonist according to any one of the preceding claims, optionally wherein the disease is pulmonary hypertension (PAH), systemic sclerosis (SSc), heart failure with preserved ejection fraction (HfpEf), age-related sarcopenia, or acute kidney injury (AKI).

31. A nucleic acid encoding an apralin receptor agonist according to any one of claims 1 to 29.

32. A method for producing an apralin receptor agonist according to any one of claims 1 to 29.

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