COMPOSITIONS AND METHODS FOR MODULATING AT2R ACTIVITY

Abstract

New polypeptide agonists of AT2R are disclosed, as well as pharmaceutical compositions comprising the agonists, methods of their use in the treatment of diseases, conditions or disorders characterized by insufficient AT2R activity or excessive AT1R activity, and methods of their use as laboratory reagents for research purposes.

Claims

1. A method of activating an AT2R protein or inhibiting an AT1R protein in a cell expressing the AT2R protein comprising: providing to the cell an effective amount of an AT2R agonist comprising an amino acid sequence that corresponds to the formula:
A1-A2-A3-A4-A5-A6 wherein: A1 is Lys A2 is Pro, 3Hyp or 4Hyp A3 is Leu or Ile A4 is Lys A5 is Pro, 3Hyp or 4Hyp, and A6 is Trp.

2. The method of claim 1 wherein said agonist is administered to a mammal in need of treatment for a condition characterized by under activation of the AT2R or insufficient activity or production of a downstream effector of AT2R selected from the group consisting of MTOR, NHE6, ErbB3, Nitric Oxide Synthase, MCL-1 and prostaglandin 12-IP.

3. The method of claim 2 wherein said condition is selected from the group consisting of diabetes, cancer involving dysfunction of ErbB3 and hypertension.

4. The method of claim 1 wherein said AT2R agonist is administered to a mammal in need of treatment for a neurological condition selected from the group consisting of autism, ALS, Alzheimer's, Parkinson's, muscular dystrophy and Huntington's Disease.

5. The method of claim 1 wherein said AT2R agonist is administered to a mammal in need of treatment for an injury selected from the group consisting of spinal cord injury, traumatic brain injury, and brain lesions.

6. The method of claim 1 wherein said AT2R agonist is administered to a mammal in need of treatment for a condition characterized by the dysregulation of the Renin-Angiotensin System.

7. The method of claim 6 wherein said condition is selected from the group consisting of hypertension, nephropathy, renal disease, cardiovascular disease and metabolic syndrome.

8. The method of claim 1 wherein the AT2R agonist is administered by introducing an mRNA which is translated in vivo to produce the drug.

9. The method of claim 1 wherein the AT2R agonist is administered to a mammal in need of treatment for a condition characterized by over activation of the AT1R.

10. The method of claim 9 wherein the condition is selected from the group consisting of nephropathy, hypertension and metabolic syndrome.

11. The method of claim 1 wherein said agonist is used as a reagent to activate the AT2R receptor for laboratory research.

12. The method of claim 1 wherein said agonist is administered to a mammal in need of treatment for a condition characterized by the under activation of miRNAs or proteins that can be activated or expressed by AT2R activator.

13. The method of claim 1 wherein said agonist is administered to a mammal in need of treatment for a condition characterized by under expression of AT2R.

14. The method of claim 1 wherein the agonist is pegylated for additional stability.

15. The method of claim 1 wherein the agonist is administered by introducing a gene sequence or isolated nucleic acid into cells via a viral vector which is expressed in vivo to produce the agonist.

16. The method of claim 1 wherein said agonist is used as a reagent to stimulate AT2R-mediated activation of D1-like receptors to modulate sodium excretion in a microfluidic simulation system.

17. The method of claim 1 wherein said agonist is used as a reagent to allow for selective inhibition of the AT1 receptor for laboratory research.

18. The method of claim 1 wherein the agonist is administered by introducing an mRNA which is translated in vivo to produce the agonist.

19. The method of claim 1 wherein the agonist is pegylated for additional stability.

20. The method of claim 1 wherein the agonist is administered by introducing a gene sequence or isolated nucleic acid into cells via a viral vector which is expressed in vivo to produce the agonist.

21. The method of claim 1 wherein the agonist is administered for conditions characterized by high blood sugar such as diabetes and metabolic syndrome.

22. The method of claim 1 wherein the cell is in vivo.

23. A pharmaceutical composition comprising a polypeptide comprising an amino acid sequence that corresponds to the formula:
A1-A2-A3-A4-A5-A6 wherein: A1 is Lys A2 is Pro, 3Hyp or 4Hyp A3 is Leu or Ile A4 is Lys A5 is Pro, 3Hyp or 4Hyp, and A6 is Trp.

24. A pharmaceutical composition comprising a polypeptide consisting essentially of an amino acid sequence that corresponds to the formula:
A1-A2-A3-A4-A5-A6 wherein: A1 is Lys A2 is Pro, 3Hyp or 4Hyp A3 is Leu or Ile A4 is Lys A5 is Pro, 3Hyp or 4Hyp, and A6 is Trp.

25. A pharmaceutical composition comprising a polypeptide consisting of an amino acid sequence that corresponds to the formula:
A1-A2-A3-A4-A5-A6 wherein: A1 is Lys A2 is Pro, 3Hyp or 4Hyp A3 is Leu or Ile A4 is Lys A5 is Pro, 3Hyp or 4Hyp, and A6 is Trp.

26. The pharmaceutical composition of claim 23 wherein the polypeptide has AT2R agonist activity when administered to a cell expressing an AT2R receptor.

27. The pharmaceutical composition of claim 23 wherein: when A2 is Pro, A5 is 3Hyp or 4Hyp; or when A5 is Pro, A2 is 3Hyp or 4Hyp.

28. The pharmaceutical composition of claim 23 wherein the composition is lyophilized.

29. The pharmaceutical composition of claim 23 further comprising a pharmaceutically acceptable carrier.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The following drawings are illustrative of embodiments of the invention and are not meant to limit the scope of the invention as encompassed by the claims.

[0028] FIG. 1 shows that an NP-6AK agonist increases MCL-1 expression in female mouse HL-1 cardiomyocytes and human CAVSMCs. CGP, a partial agonist was unable to increase MCL-1. Addition of PD, an AT2R antagonist prevents NP-6AK-mediated up regulation of MCL-1, indicating that this effect is via AT2R.

[0029] FIG. 2 shows immunofluorescence staining of SH-SY5Y cells subjected to treatments (24 hours) using an NP-6AK agonist with anti-MCL-1 antibody and nuclear stain DAPI. n≧80 and *p<0.01 compared to control. The NP-6AK agonist was more effective than the control for up regulation of MCL-1.

[0030] FIG. 3 shows that an NP-6AK agonist promotes neurite elongation and reverses rapamycin-mediated suppression in SH-SY5Y cells.

[0031] FIG. 4 shows data from studies with ex vivo tissue that demonstrated that an NP-6AK agonist provided neuroprotection to normal primary murine embryonic cortical neurons in culture when challenged with nutrient deprivation. For nutrient deprivation, primary cortical neurons (14 DIV) were incubated in glucose-free Locke's medium with or without 300 nm NP-6AK agonist. Cells treated with an NP-6AK agonist had a 60% increased activity (p<0.05) compared with negative controls, corroborating previous data showing increased cell viability under conditions of serum starvation and neuroprotection.

DETAILED DESCRIPTION

[0032] AT2R activation is suppressed in a variety of disease states including hypertension, diabetes, cancers and various neurodegenerative diseases. Suppression of AT2R leads to increased activity of the AT1R which is a major contributor to metabolic diseases (e.g., cardiovascular and renal diseases, type 2 diabetes) and cancers. Therefore, the present invention provides a new class of laboratory reagents and therapeutic polypeptides which can be used to characterize and treat such disorders.

References and Definitions

[0033] The patent and scientific literature referred to herein establishes knowledge that is available to those of skill in the art. The issued U.S. patents, pending U.S. applications, published foreign patents and applications, and references, including protein and nucleotide database sequences, that are cited herein are hereby incorporated by reference to the same extent as if each was specifically and individually indicated to be incorporated by reference.

[0034] As used herein, the terms “about” or “approximately” mean within twenty percent (20%) of the numerical amount cited.

[0035] As used herein, the term “a” means one or more.

[0036] As used herein, the terms “increased” or “decreased” mean at least 10% more or less, respectively, relative to pre-treatment with an agonist of the invention.

[0037] As used herein, a “pharmaceutical composition” includes an active agent and a pharmaceutically acceptable carrier.

[0038] As used herein, the phrase “pharmaceutically acceptable” refers to molecular entities and compositions that are physiologically tolerable and do not typically produce a severe allergic, pyrogenic or similarly undesired reaction when administered to a mammal.

[0039] As used herein, the term “carrier” refers to a diluent, adjuvant, excipient, or vehicle with which a compound is administered. Such pharmaceutical carriers can be sterile liquids, such as water and oils, including those of petroleum, animal, vegetable or synthetic origin, such as peanut oil, soybean oil, mineral oil, sesame oil and the like. Water or other aqueous solutions, saline solutions, aqueous dextrose and glycerol solutions may be employed as carriers, particularly for injectable solutions. Suitable pharmaceutical carriers are described in “Remington's Pharmaceutical Sciences” by E. W. Martin (61).

Polypeptide Modulators of AT2R Activity

[0040] The invention provides a new class of agonists which are polypeptides (or polypeptide derivatives or analogues) comprising 6 amino acid residues with the generic sequence A1-A2-A3-A4-A5-A6, where A1 is Lys; A2 is Pro, 3Hyp or 4Hyp; A3 is Leu or Ile; A4 is Lys, A5 is Pro, 3Hyp or 4Hyp, and A6 is Trp. This new class is referred to as NP-6AK agonists. Sequences with Hyp in at least one position may be preferred due to increased stability. Other derivatives or analogues of these agonists may include chemical modifications that increase stability in the bloodstream for use as a pharmaceutical reagent.

[0041] One possible modification is formation of non-natural peptide bonds for additional stability or the attachment of the side chain atoms to a different atom of the residue, An example of such chemistry is cited in Hook et al. (60). The authors describe beta amino acids, wherein the side chains are attached to the beta carbon, whereas natural amino acid side chains are attached to the alpha carbon. Various studies have shown that these “beta peptides” are less likely to be degraded by non-specific peptidases compared to natural peptides. Any such chemistry that modifies the natural peptide for additional stability could be used, including peptoids in which the side chain is attached to the nitrogen.

[0042] Another method of stabilizing the polypeptides of the invention is covalent or non-covalent association with an inert water-soluble polymer. When administered systemically, therapeutic compositions are often cleared rapidly from the circulation and may therefore elicit relatively short-lived pharmacological activity. Consequently, frequent injections of relatively large doses of bioactive compounds may be required to sustain therapeutic efficacy. Any water-soluble (e.g., at least about 0.01 mg/ml) inert polymer which provides the conjugate with the desired increase in stability or half-life is suitable for use in the invention. Non-proteinaceous polymers are particularly preferred. The polymer is preferably a hydrophilic synthetic polymer, such as a polyvinyl polymer (e.g., polyvinylalcohol and polyvinylpyrrolidone), polyalkylene ether (e.g., polyethylene glycol (PEG)); polyoxyalkylene (e.g., polyoxyethylene, polyoxypropylene, and block copolymers of polyoxyethylene and polyoxypropylene (Pluronics)); polymethacrylate; or carbomer. However, natural polymers are also useful, such as branched or unbranched polysaccharides which comprise the saccharide monomers D-mannose, D- and L-galactose, fucose, fructose, D-xylose, L-arabinose, D-glucuronic acid, sialic acid, D-galacturonic acid, D-mannuronic acid (e.g., polymannuronic acid, or alginic acid), D-glucosamine, D-galactosamine, D-glucose and neuraminic acid including, for example, lactose, amylopectin, starch, hydroxyethyl starch, amylose, dextran sulfate, dextran, dextrins, glycogen, or polymers of sugar alcohols such as polysorbitol and polymannitol, heparin or heparan. The molecular weight of the polymer can range from about 10,000 to 500,000 Daltons (D), and may typically be about 20,000 D, about 30,000 D, about 40,000 D, or about 50,000 D.

[0043] Compounds modified by the covalent attachment of water-soluble polymers such as polyethylene glycol (PEG), copolymers of polyethylene glycol and polypropylene glycol, or monomethoxypolyethylene glycol (mPEG), carboxymethyl cellulose, dextran, polyvinyl alcohol, polyvinylpyrrolidone or polyproline are known to exhibit substantially longer half-lives in blood following intravenous injection than do the corresponding unmodified compounds. Such modifications may also increase the composition's solubility in aqueous solution, reduce aggregation, increase the physical or chemical stability of the compound, and reduce the immunogenicity and reactivity of the composition.

[0044] Attachment of polyethylene glycol (PEG) to agonist compositions of the invention is particularly useful because PEG has very low toxicity in mammals and may reduce the immunogenicity or antigenicity of the agonist compositions. Numerous activated forms of PEG suitable for direct reaction with proteins have been described. Useful PEG reagents for reaction with protein amino groups include active esters of carboxylic acid or carbonate derivatives, particularly those in which the leaving groups are N-hydroxysuccinimide, p-nitrophenol, imidazole or 1-hydroxy-2-nitrobenzene-4-sulfonate. PEG derivatives containing maleimido or haloacetyl groups are useful reagents for the modification of protein free sulfhydryl groups. Likewise, PEG reagents containing amino hydrazine or hydrazide groups are useful for reaction with aldehydes generated by periodate oxidation of carbohydrate groups in proteins.

[0045] The agonist compositions of the present invention may be delivered in a microencapsulation device so as to reduce or prevent a host immune response against the polypeptide or against cells which may produce the polypeptide. The polypeptide or compositions of the present invention may also be delivered microencapsulated in a membrane, such as a liposome. As an example, polymers such as PEG may be conveniently attached to one or more reactive amino acid residues in a polypeptide of the agonist compositions, such as the alpha-amino group of the amino terminal amino acid, the epsilon amino groups of lysine side chains, the sulfhydryl groups of cysteine side chains, the carboxyl groups of aspartyl and glutamyl side chains, the alpha-carboxyl group of the carboxy-terminal amino acid, tyrosine side chains, or to activated derivatives of glycosyl chains attached to certain asparagine, serine or threonine residues.

[0046] Another method of modifying the polypeptide agonists of the invention is to add a signal sequence to the N- or C-terminus. The term “signal sequence,” as used herein, refers to any short peptide that directs the trafficking of a protein in the cell. Signal sequences may, for example, direct secretion of a polypeptide, or localization within an intracellular compartment. Signal sequences also frequently determine the orientation of a peptide across a cell membrane. One example is an N-terminal sequence of about 20 amino acids that directs secretory and transmembrane proteins to the endoplasmic reticulum (ER) (see, e.g., von Heijne (1985), J. Mol. Biol. 184:99-105). Signal sequences may also be engineered to include one or more specific protease recognition sites, such that the signal sequences will be removed by endogenous proteases after trafficking.

AT2R Agonist Reagents

[0047] Activation of AT2R in laboratory testing is of high interest due to the many effects of AT2R described above. Therefore, in one aspect, the invention provides AT2R agonists as in vitro or in vivo reagents for laboratory research.

[0048] Thus an NP-6AK agonist to AT2R has utility as a control to characterize and quantify downstream effects of the receptor activation, such as its effects on the mammalian target of rapamycin (MTOR), NHE6, ErbB3 and Nitric Oxide Synthase.

[0049] For example, CHO cells expressing AT2R and MTOR are treated with an NP-6AK agonist and insulin to activate both MTOR and AT2R. AT2R suppresses MTOR-mediated phosphorylation of Ribosomal Protein S6 (RPS6). Western blotting can be used to determine RPS6 phosphorylation state which is decreased by at least 10% in response to AT2R activation by the agonist NP-6AK. The same cell line can then be treated with a different AT2R agonist candidate to assess the efficacy of the agonist candidate, or the same cell line can be treated with both an AT2R agonist of the invention and an AT2R antagonist candidate (e.g., EMA300, Smith et al. (2013), Pain Medicine 14(10):1557-68; PD123319, Chakrabarty et al. (2008), Endocrinology 149(7):3452) to assess the efficacy and mode of action (i.e., competitive, non-competitive) of the antagonist candidate.

[0050] An NP-6AK agonist increases expression levels of at least one, and in some embodiments all three, MCL-1 isoforms.

Methods of Treatment

[0051] In order to treat an AT1R-mediated inflammatory response or an inflammatory response arising from under-activation of the AT2R, and/or the symptoms arising therefrom, an NP-6AK agonist is administered by any route that will permit delivery of the active agent to the affected cells. In some embodiments, administration is subcutaneous, intramuscular or intraperitoneal, but may also be by inhalation, intra-arterial, intravenous, intradermal, topical, oral, parenteral, intraventricular, or intracranial administration. Alternatively, the active agent may be delivered locally to the system or the affected cells by any suitable means.

[0052] In therapeutic treatments of the invention, a therapeutically effective amount of the pharmaceutical composition is administered to a mammalian patient. As used herein, the term “therapeutically effective amount” means an amount sufficient to reduce by at least 15 percent, preferably by at least 50 percent, more preferably by at least 90 percent, and most preferably substantially eliminate or prevent, a clinically significant metric or deficit in the activity, function and response of the patient. Specifically, a therapeutically effective amount will cause one or more of the following: decreased AT1R activation, increased AT2R activation; decreased cortisol levels; stabilized insulin levels; decreased pro-inflammatory cytokines, decreased pro-inflammatory interleukins, increased function of dopaminergic neurons, decreased Reactive Oxygen Species, decreased mucous production, or a decrease or increase in any other relevant markers as discussed herein or that would be known to one of ordinary skill in the art as it relates to cystic fibrosis (CF), diabetes, metabolic X syndrome; hyperglycemia, autism, Alzheimer's disease, inflammation or cancer. The frequency and dosage of the therapy can be titrated by the ordinary physician or veterinarian using standard dose-to-response techniques that are well known in the art.

Pharmaceutical Formulations

[0053] Liquid forms, such as lotions suitable for topical administration or for cosmetic application, may include a suitable aqueous or non-aqueous vehicle with buffers, suspending and dispensing agents, thickeners, penetration enhancers, and the like. Solid forms such as creams or pastes or the like may include, for example, any of the following ingredients, water, oil, alcohol or grease as a substrate with surfactant, polymers such as polyethylene glycol, thickeners, solids and the like. Liquid or solid formulations may include enhanced delivery technologies such as liposomes, microsomes, microsponges and the like.

[0054] The above-described components for liquid, semisolid and solid topical compositions are merely representative. Other materials as well as processing techniques and the like are set forth in Part 8 of Remington's Pharmaceutical Sciences, 17th edition, 1985, Mack Publishing Company, Easton, Pa., which is incorporated herein by reference.

[0055] When pharmaceutical compositions are to be administered transdermally they typically are employed as liquid solutions or as gels. In these settings the concentration of agonists of the present invention range from about 0.1% to about 20%, and preferably from about 0.1% to about 10%, of the composition with the remainder being aqueous mixed or non-aqueous vehicle, such as alcohols and the like, suspending agents, gelling agents, surfactant, and the like. Examples of suitable such materials are described below.

[0056] The agonist-containing compositions of this invention can also be administered in sustained release transdermal forms or from transdermal sustained release drug delivery systems. A description of representative sustained release materials can be found in the incorporated materials in Remington's Pharmaceutical Sciences, supra.

[0057] The agonist compositions for systemic administration include compositions for oral administration, that is liquids and solids, and compositions for injection.

[0058] Compositions for oral administration can take the form of bulk liquid solutions or suspensions, or bulk powders. More commonly, however, the compositions are presented in unit dosage forms to facilitate accurate dosing. The term “unit dosage forms” refers to physically discrete units suitable as unitary dosages for human subjects and other mammals, each unit containing a predetermined quantity of active material calculated to produce the desired therapeutic effect, in association with a suitable pharmaceutical solvent. Typical unit dosage forms include profiled, premeasured ampules or syringes of the liquid compositions or pills, tablets, capsules or the like in the case of solid compositions. According to one embodiment, an agonist composition of the present invention is usually a minor component (from about 0.01 to about 20% by weight or preferably from about 0.1 to about 15% by weight) with the remainder being various vehicles or carriers and processing aids helpful for forming the desired dosing form.

[0059] Liquid forms suitable for oral administration may include a suitable aqueous or nonaqueous vehicle with buffers, suspending and dispensing agents, colorants, flavors and the like. Solid forms may include, for example, any of the following ingredients, or compounds of a similar nature including a binder such as microcrystalline cellulose, gum tragacanth or gelatin; an solvent such as starch or lactose, a disintegrating agent such as alginic acid, Primogel, or corn starch; a lubricant such as magnesium stearate; a glidant such as colloidal silicon dioxide; a sweetening agent such as sucrose or saccharin; or a flavoring agent such as peppermint, methyl salicylate, or orange flavoring.

[0060] According to another embodiment, injectable compositions are typically based upon injectable sterile saline or phosphate-buffered saline or other injectable carriers known in the art. A compound of the present invention in such compositions is typically a minor component, about 0.1-30% by weight, with the remainder being the injectable carrier and the like.

[0061] The above-described components for orally administrable or injectable compositions are merely representative. Other materials as well as processing techniques and the like are set forth in the part of Remington's Pharmaceutical Sciences noted above.

EXAMPLES

[0062] The NP-6AK agonists if the invention, including polypeptides comprising, consisting of, or consisting essentially of the sequences Lys-Pro-Leu-Lys-Pro-Trp; Lys-3Hyp-Leu-Lys-Pro-Trp; Lys-4Hyp-Leu-Lys-Pro-Trp; Lys-Pro-Ile-Lys-Pro-Trp; Lys-3Hyp-Ile-Lys-Pro-Trp; Lys-4Hyp-Ile-Lys-Pro-Trp; Lys-Pro-Leu-Lys-3Hyp-Trp; Lys-3Hyp-Leu-Lys-3Hyp-Trp; Lys-4Hyp-Leu-Lys-3Hyp-Trp; Lys-Pro-Ile-Lys-3Hyp-Trp; Lys-3Hyp-Ile-Lys-3Hyp-Trp; Lys-4Hyp-Ile-Lys-3Hyp-Trp; Lys-Pro-Leu-Lys-4Hyp-Trp; Lys-3Hyp-Leu-Lys-4Hyp-Trp; Lys-4Hyp-Leu-Lys-4Hyp-Trp; Lys-Pro-Ile-Lys-4Hyp-Trp; Lys-3Hyp-Ile-Lys-4Hyp-Trp; and Lys-4Hyp-Ile-Lys-4Hyp-Trp, can be tested in various cell-based systems to demonstrate AT2R agonist activity, and utility in the methods described herein.

[0063] Thus, an NP-6AK agonist comprising the sequence Lys-Pro-Leu-Lys-Pro-Trp promoted cell survival across mouse HL-1 cardiomyocytes and human smooth vascular muscle cells by acting through AT2R activation. Cell survival was assessed by measurement of cell index (CI) using a Xcelligence™ Real-Time Cell Analyzer (Westburg B V, Leusden, N L) to quantitatively determine the effect of different treatments on cell survival, adhesion, and proliferation. Cell lines treated with the NP-6AK agonist (300 nM) demonstrated significantly better survival and more proliferation than those treated with CGP42112A (300 nM) (Sigma-Aldrich, Co. LLC, St. Louis, Mo.), a partial agonist of AT2R. CGP42112A and the NP-6AK agonist (300 nM) increased CI of serum starved HL-1 cells in the order CGP42112A (≧14%), NP-6AK (≧25%). Increase in CI is a direct effect of AT2R activation. This was verified by addition of an AT2R antagonist, PD123319 (Sigma-Aldrich, Co. LLC, St. Louis, Mo.). In the presence of this antagonist, the cell survival otherwise observed using the NP-6AK agonist was not present.

[0064] An NP-6AK agonist upregulated MCL-1 by selectively activating AT2R across several cell lines. This effect was observed in cardiomyocytes, human vascular smooth muscle cells, SH-SY5Y cells (ATCC, Manassas, Va.), and PC-12 neuronal cells (ATCC, Manassas, Va.) in conditions of serum starvation and/or toxicity. When incubated with an NP-6AK agonist at a concentration of 300 nM, cardiomyocytes displayed 45% higher MCL-1 expression and human smooth vascular muscle cells displayed 22% higher MCL-1 expression (FIG. 1). When any of these cell lines was pre-treated with an AT2R antagonist such as PD123319, the MCL-1 upregulation was not observed, implying that NP-6AK activation of AT2R is necessary for MCL-1 upregulation. Cells treated with the NP-6AK agonist generated higher MCL-1 upregulation relative to those treated with a partial agonist such as CGP42112A.

[0065] The SH-SY5Y cell line is a neuronal cell line with both dopaminergic and adrenergic receptors. When this cell line was treated with Rapamycin, MCL-1 expression was reduced. Addition of an NP-6AK agonist to this cell line after treatment with Rapamycin was able to recover MCL-1 expression. When just the NP-6AK agonist was added at a concentration of 300 nM, these cells displayed 2-fold increase in MCL-1 expression. See FIG. 2.

[0066] Serum-starvation reduced survival of SH-SY5Y cells and PC-12 cells. When these cell lines were treated with an NP-6AK agonist, they had a higher survival rate and demonstrated increased MCL-1 expression and neurite elongation. See FIG. 3. When PC-12 cells were treated with AT2R antagonist PD123319, the protective effects of the NP-6AK agonist were lost, indicating that the NP-6AK agonist's direct action is through AT2R activation. Treatment of this cell line with 300 nM of NP-6AK agonist led to increased cell viability by over 30% relative to treatment with native ligand of AT2R Ang II (300 nM). Relative to treatment with 300 nM CGP42112A, cells treated with an NP-6AK agonist displayed over 70% increased survival. Treatment with AngII or CGP42112A was more detrimental relative to results obtained when cells are treated with AT2R antagonist PD123319. AT2R activation by NP-6AK agonist promotes cell survival whereas AT2R activation by other ligands are harmful to it. These results were assessed using an MTS cell proliferation assay (Biovision Inc., Milpitas, Calif.).

[0067] Ex vivo neurons were obtained and treated with an NP-6AK agonist in different conditions to assess neuroprotective properties. Normal primary murine embryonic cortical neurons in culture (14 days in vitro) were challenged with nutrient deprivation by incubation in glucose-free Locke's medium (Schnapf et al. (1990)). These cultures were then supplemented with 300 nM NP-6AK agonist or no NP-6AK agonist. Cultures that were supplemented 300 nm NP-6AK agonist demonstrated 60% increased activity (p<0.05) compared with negative controls. See FIG. 4.

[0068] Zucker Obese (ZO) rats (Charles River Laboratories, Inc., Wilmington, Mass.), a diabetic animal model displaying signs of cardiovascular disease were treated for 2 weeks (dose of 0.9 mg/kg/day) via subcutaneous injection with an NP-6AK agonist and assessed for several markers of cardiovascular health including blood markers and structural parameters of the heart. Controls were ZO rats that received saline. Fasting plasma and urine profiles demonstrated that animals receiving the NP-6AK agonist had reduced triglycerides (˜50%), urine protein (˜68%), reduced urine N-acetyl-beta-A-glucosaminidase (˜60%), and increased HDL by 12% on average. Echocardiography performed using the Vevo® 2100 platform (VisualSonics, Toronto, Ontario, CA) indicated that animals treated with the NP-6AK agonist had improved structural cardiac parameters including circumferential strain of endocardium (short axis view), and myocardial performance index (MPI) (p≦0.005), and E/E′ ratio (p≦0.002), a powerful predictor of primary cardiac events. See Table 1.

TABLE-US-00001 TABLE 1 Treatment groups Plasma Profile Urine Profile (2 Weeks; Saline or mg/dL mg/dL Echocardiography/Strain analysis NP-6A 0.9 mg/kg/day) Triglycerides HDL Protein NA6 MPI E/E Circumferential Strain Male ZO rat ± Saline 1229 ± 164 65 ± 4.1 1426.7 ± 649.5 27.9 ± 6.4 0.516 ± 0.03 32.3 ± 2.06 −20.56 ± 1.65 Male ZO rat ± NP-6A  610 ± 109 73 ± 2.8   445 ± 86.4 10.9 ± 1.5 0.389 ± 0.02  26 ± 2.1 −26.11 ± 2.47

[0069] Although the invention has been described in detail with particular reference to these preferred embodiments, other embodiments can achieve the same results. Variations and modifications of the present invention will be obvious to those skilled in the art and it is intended to cover in the appended claims all such modifications and equivalents. The entire disclosures of all references, applications, patents, and publications cited herein are hereby incorporated by reference.

REFERENCES

[0070] 1. Kalupahana and Moustaid-Moussa (2012), “The renin-angiotensin system: a link between obesity, inflammation and insulin resistance,” Obes. Rev. 13(2):136-49. [0071] 2. Santos et al. (2014), “The Therapeutic Role of Renin-Angiotensin System Blockers in Obesity-Related Renal Disorders,” Curr. Clin. Pharmacol. 9(1):2-9. [0072] 3. Saavedra et al. (2011), “Blockade of brain angiotensin II AT1 receptors ameliorates stress, anxiety, brain inflammation and ischemia: Therapeutic implications,” Psychoneuroendocrinology 36(1):1-18. [0073] 4. Herr et al. (2008), “Potential role of Renin-Angiotensin-system for tumor angiogenesis in receptor negative breast cancer,” Gynecol. Oncol. 109:418-25. [0074] 5. Kintscher et al. (2009), “Inhibiting angiotensin type 1 receptors as a target for diabetes,” Expert Opin. Ther. Targets 10:1257-63. [0075] 6. Vinson et al. (2012), “The renin-angiotensin system in the breast and breast cancer,” Endocr. Relat. Cancer 19(1):R1-19. [0076] 7. Steckelings et al. (2012), “AT2 receptor agonists: hypertension and beyond,” Curr. Opin. Nephrol. Hypertens. 21(2):142-6. [0077] 8. McCarthy et al. (2009), “Angiotensin AT2 receptor stimulation causes neuroprotection in a conscious rat model of stroke,” Stroke 40:1482-9. [0078] 9. Ferreira et al. (2010), “Therapeutic implications of the vasoprotective axis of the renin-angiotensin system in cardiovascular diseases,” Hypertension 55(2):207-13. [0079] 10. Doi et al. (2010), “Angiotensin II type 2 receptor signaling significantly attenuates growth of murine pancreatic carcinoma grafts in syngeneic mice,” BMC Cancer 10:67. [0080] 11. Pickel et al. (2010), “Overexpression of angiotensin II type 2 receptor gene induces cell death in lung adenocarcinoma cells,” Cancer Biol. Ther. 9(4):277-85. [0081] 12. Brown et al. (2006), “AT2 receptor stimulation may halt progression of pheochromocytoma,” Ann. N.Y. Acad. Sci. 1073:436-43. [0082] 13. Adachi et al. (2003), “Angiotensin II type 2 receptor deficiency exacerbates heart failure and reduces survival after acute myocardial infarction in mice,” Circulation. 107:2406-8. [0083] 14. Ohinata et al. (2009), “Orally administered novokinin, an angiotensin AT2 receptor agonist, suppresses food intake via prostaglandin E2-dependent mechanism in mice,” Peptides 30:1105-8. [0084] 15. Unger and Dahlöf (2010), “Compound 21, the first orally active, selective agonist of the angiotensin II type 2 (AT2) receptor: implications for AT2 receptor research and therapeutic potential,” J. Renin Angiotensin Aldosterone Syst. 11:75-7. [0085] 16. Qi et al. (2012), “Moderate cardiac-selective overexpression of angiotensin II type 2 receptor protects cardiac functions from ischaemic injury,” Exp. Physiol. 97:89-101. [0086] 17. Oishi et al. (2006), “AT2 receptor mediates the cardioprotective effects of AT1 receptor antagonist in post-myocardial infarction remodeling, Life Sci. 80(1):82-8. [0087] 18. Carey et al. (2000), “Role of the Angiotensin Type 2 Receptor in the Regulation of Blood Pressure and Renal Function,” Hypertension 35(1):155-163. [0088] 19. Ohinata et al. (2009), “Orally administered novokinin, an angiotensin AT2 receptor agonist, suppresses food intake via prostaglandin E2-dependent mechanism in mice,” Peptides 30:1105-1108. [0089] 20. Guimond and Gallo-Payet (2012), “How does angiotensin AT(2) receptor activation help neuronal differentiation and improve neuronal pathological situations?” Front Endocrinol. (Lausanne) 3:164. [0090] 21. Siragy and Carey (1997), “The subtype 2 (AT2) angiotensin receptor mediates renal production of nitric oxide in conscious rats, J. Clin. Invest. 100:264-269. [0091] 22. Widdop et al. (2002), “AT2 receptor-mediated relaxation is preserved after long-term AT1 receptor blockade,” Hypertension 40:516-520. [0092] 23. Yayama et al. (2006), “Angiotensin II stimulates endothelial NO synthase phosphorylation in thoracic aorta of mice with abdominal aortic banding via type-2 receptor,” Hypertension 48:958-964. [0093] 24. Rodrigues-Ferreira and Nahmias (2010), “An atypical family of angiotensin II AT2 receptor-interacting proteins,” Trends Endocrinol. Metab. 21:684-690. [0094] 25. Knowle et al. (2000), “Identification of an interaction between the angiotensin II receptor sub-type AT2 and the ErbB3 receptor, a member of the epidermal growth factor receptor family,” Regul. Pept. 87(1-3):73-82. [0095] 26. Pulakat et al. (2005), “Ligand-dependent complex formation between the Angiotensin II receptor subtype AT2 and Na+/H+ exchanger NHE6 in mammalian cells,” Peptides 26(5):863-73. [0096] 27. Yamada et al. (1996), “Angiotensin II type 2 receptor mediates programmed cell death,” Proc. Natl. Acad. Sci. (USA) 93(1):156-60. [0097] 28. Lehtonen et al. (1999), “Analysis of functional domains of angiotensin II type 2 receptor involved in apoptosis,” Mol. Endocrinol. 13(7):1051-60. [0098] 29. Pulakat et al. (2005), “Roles of the intracellular regions of angiotensin II receptor AT2 in mediating reduction of intracellular cGMP levels,” Cell Signal. 17(3):395-404. [0099] 30. Pulakat et al. (2002), “Role of C-terminal cytoplasmic domain of the AT2 receptor in ligand binding and signaling,” FEBS Lett. 524(1-3):73-8. [0100] 31. Gendron et al. (2003), “The angiotensin type 2 receptor of angiotensin II and neuronal differentiation: from observations to mechanisms,” J. Mol. Endocrinol. 31(3):359-72. [0101] 32. Rodriguez-Pallares et al. (2004), “Angiotensin II increases differentiation of dopaminergic neurons from mesencephalic precursors via angiotensin type 2 receptors,” Eur. J. Neurosci. 20(6):1489-98. [0102] 33. Zawada et al. (2005), “Angiotensin II protects cultured midbrain dopaminergic neurons against rotenone-induced cell death,” Brain Res. 1045(1-2):64-71. [0103] 34. Mendelsohn et al. (1988), “Localization of angiotensin II receptor binding in rabbit brain by in vitro autoradiography,” J. Comp. Neurol. 270:372-384. [0104] 35. Unger et al. (1988), “Brain angiotensin: pathways and pharmacology,” Circulation 77(60):I40-54. [0105] 36. Severs and Daniels-Severs (1973), “Effects of angiotensin on the central nervous system,” Pharmacol. Rev. 25:415-449. [0106] 37. Phillips (1987), “Functions of angiotensin in the central nervous system,” Ann. Rev. Physiol. 49:413-435. [0107] 38. Nuyt et al. (1999), “Ontogeny of angiotensin II type 2 receptor mRNA expression in fetal and neonatal rat brain,” J. Comp. Neurol. 407:193-206 [0108] 39. Song et al. (1992), “Mapping of angiotensin II receptor subtype heterogeneity in rat brain,” J. Comp. Neurol. 316:467-484. [0109] 40. Lenkei et al. (1996), “Distribution of angiotensin II type-2 receptor (AT2) mRNA expression in the adult rat brain,” J. Comp. Neurol. 373:322-339. [0110] 41. Lenkei et al. (1997), “Expression of angiotensin type-1 (AT1) and type-2 (AT2) receptor mRNAs in the adult rat brain: a functional neuroanatomical review,” Front. Neuroendocrinol. 18:383-439. [0111] 42. Bottari et al. (1992), “Characterization and distribution of angiotensin II binding sites in fetal and neonatal astrocytes from different rat brain regions,” Brain Res. 585:372-376.A. [0112] 43. Okamura et al. (1999), “Upregulation of renin-angiotensin system during differentiation of monocytes to macrophages,” J. Hypertens. 17(4):537-545. [0113] 44. Nahmod et al. (2003), “Control of dendritic cell differentiation by angiotensin II,” FASEB J. 17(3):491-493. [0114] 45. Iwanami et al. (2011), “Effect of angiotensin II type 2 receptor deletion in hematopoietic cells on brain ischemia-reperfusion injury,” Hypertension 58(3):404-409. [0115] 46. Borlongan et al. (2011), “The great migration of bone marrow-derived stem cells toward the ischemic brain: therapeutic implications for stroke and other neurological disorders,” Prog. Neurobiol. 95(2):213-228. [0116] 47. Padia et al. (2012), “Mechanisms of dopamine D(1) and angiotensin type 2 receptor interaction in natriuresis,” Hypertension 59(2):437-45. [0117] 48. Namsolleck et al. (2013), “AT2-receptor stimulation enhances axonal plasticity after spinal cord injury by upregulating BDNF expression,” Neurobiol Dis. 51:177-91. [0118] 49. Guimond et al. (2013), “Expression and role of the angiotensin II AT2 receptor in human prostate tissue: in search of a new therapeutic option for prostate cancer.” The Prostate 73(10):1057-1068. [0119] 50. Wruck et al. (2005), “Regulation of transport of the angiotensin AT2 receptor by a novel membrane-associated Golgi protein,”Arterioscler. Thromb. Vasc. Biol. 25(1):57-64. [0120] 51. Libby et al. (2002), “Inflammation and Atherosclerosis,” Circulation 105(9):1135-1143. [0121] 52. LaMarca (2011), “Hypertension in Response to IL-6 During Pregnancy: Role of AT1-receptor Activation.” Int. J. Interferon Cytokine Mediator Res. 2011(3):65-70. [0122] 53. Mitra et al. (2010), “Angiotensin II-induced Upregulation of AT1-receptor Expression: Sequential Activation of NFkB and Elk-1 in Neurons.”Am. J. Physiol. Cell Physiol. 299(3):C561-9. [0123] 54. Mizushima et al. (2010), “Blockage of Angiotensin II Type 1 Receptor Regulates TNF-α-induced MAdCAM-1 Expression via Inhibition of NF-κB Translocation to the Nucleus and Ameliorates Colitis.”Am. J. Physiol. Gastrointest. Liver Physiol. 298(2): G255-G266. [0124] 55. Dronavalli et al. (2008), “The pathogenesis of diabetic nephropathy.” Nat. Clin. Pract. Endocrinol. Metab. 4(8):444-452. [0125] 56. Parving et al. (2012), “Cardiorenal End Points in a Trial of Aliskiren for Type 2 Diabetes.” New Eng. J. Med. 367(23):2204-2213. [0126] 57. Harel et al. (2012), “The Effect of Combination Treatment with Aliskiren and Blockers of the Renin-angiotensin System on Hyperkalaemia and Acute Kidney Injury: Systematic Review and Meta-analysis.” BMJ 344(1):e42-e42. [0127] 58. Liebson and Amsterdam (2009), “Ongoing Telmisartan Alone and in Combination With Ramipril Global Endpoint Trial (ONTARGET): Implications for Reduced Cardiovascular Risk.” Prev. Cardiol. 12(1):43-50. [0128] 59. Unger (2003), “The Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial Program,” Am. J. Cardiol. 91(10A):28G-34G. [0129] 60. Hook et al. (2005), “The Proteolytic Stability of ‘Designed’ Beta-peptides Containing Alpha-peptide-bond Mimics and of Mixed Alpha,beta-peptides: Application to the Construction of MHC-binding Peptides,” Chem. Biodivers. 2(5):591-632. [0130] 61. Remington's Pharmaceutical Sciences (18th Ed., E. W. Martin (ed.), Mack Publishing Co., Easton, Pa. [0131] 62. Abadir et al. (2011), “Identification and Characterization of a Functional Mitochondrial Angiotensin System,” Proc. Natl. Acad. Sci. (USA) 108(36):14849-14854. [0132] 63. Thathiah and De Strooper (2011), “The Role of G Protein-coupled Receptors in the Pathology of Alzheimer's Disease,” Nat. Rev. Neurosci. 12(2):73-87. [0133] 64. Abdalla et al. (2009), “Angiotensin II AT2 Receptor Oligomers Mediate G-protein Dysfunction in an Animal Model of Alzheimer Disease,” J. Biol. Chem. 284(10):6554-6565. [0134] 65. Kurihara et al. (2006), “Neuroprotective Effects of Angiotensin II Type 1 Receptor (AT1R) Blocker, Telmisartan, via Modulating AT1R and AT2R Signaling in Retinal Inflammation,” Invest. Ophthalmol. Vis. Sci. 47(12):5545-5552. [0135] 66. Benigni et al. (2009), “Disruption of the Ang II Type 1 Receptor Promotes Longevity in Mice,” J. Clin. Invest. 119(3):524-530. [0136] 67. Weir et al. (2012), “CNS SIRT3 Expression Is Altered by Reactive Oxygen Species and in Alzheimer's Disease,” PLoS ONE 7(11):e48225. [0137] 68. Deane et al. (2013), “Enhanced recruitment of endosomal Na+/H+ exchanger NHE6 into Dendritic spines of hippocampal pyramidal neurons during NMDA receptor-dependent long-term potentiation.” J. Neurosci. 33(2):595-610. [0138] 69. Schwede et al. (2013), “Genes for Endosomal NHE6 and NHE9 Are Misregulated in Autism Brains,” Mol. Psychiatry 19(3):277-9. [0139] 70. Xinhan et al. (2011), “Na+/H+ Exchanger Isoform 6 (NHE6/SLC9A6) Is Involved in Clathrin-dependent Endocytosis of Transferrin,” Am. J. Physiol. Cell Physiol. 301(6):C1431-C1444. [0140] 71. Kumar et al. (2002), “Identification of the Region of AT2 Receptor Needed for Inhibition of the AT1 Receptor-mediated Inositol 1,4,5-triphosphate Generation.” FEBS Lett. 532(3):379-86. [0141] 72. Hetrick et al. (2008), “Ligand mediated protein-protein interaction between the angiotensin receptor type AT1 and the human NHE6 isoform.” FASEB J. 22:726.5. [0142] 73. Gul et al. (2012), “RAS-Mediated Adaptive Mechanisms in Cardiovascular Tissues: Confounding Factors of RAS Blockade Therapy and Alternative Approaches,” Cardiorenal Med. 2(4):268-280. [0143] 74. Shieh et al. (2009), “Modification of alternative splicing of Mcl-1 pre-mRNA using antisense morpholino oligonucleotides induces apoptosis in basal cell carcinoma cells,” J. Invest. Dermatol. 129(10):2497-506. [0144] 75. Bae et al. (2000), “MCL-1S, a splicing variant of the antiapoptotic BCL-2 family member MCL-1, encodes a proapoptotic protein possessing only the BH3 domain,” J. Biol. Chem. 275(33):25255-61. [0145] 76. Yang et al. (1996), “MCL-1, a member of the BLC-2 family, is induced rapidly in response to signals for cell differentiation or death, but not to signals for cell proliferation,” J. Cell Physiol. 166(3):523-36. [0146] 77. Thomas et al. (2010), “Mcl-1: the molecular regulation of protein function,” FEBS Lett. 584(14):2981-9.