Compositions and methods of inhibiting the binding of plasma IGG autoantibodies to serotonin 2A receptor

1. A decoy peptide consisting of the sequence of SCLLADDN (SEQ ID NO: 2), wherein at least one amino acid residue of the decoy peptide is modified to comprise an acetyl group, a fluorenylmethoxy carbonyl group, a formyl group, a palmitoyl group, a myristyl group, a stearyl group, or polyethylene glycol, and wherein the decoy peptide inhibits the binding of 5-HT2A receptor autoantibodies to a second extracellular loop region of the 5-HT2A receptor.

2. The decoy peptide of claim 1 , wherein the decoy peptide is formulated for intravenous, subcutaneous, intranasal or oral administration.

3. A pharmaceutical composition comprising the decoy peptide of claim 1 , and a pharmaceutically acceptable carrier.

4. A method lowering blood pressure in a subject, the method comprising: administering to the subject a therapeutically effective amount of a pharmaceutical composition comprising a decoy peptide consisting of the sequence of SEQ ID NO: 2, wherein at least one amino acid residue of the decoy peptide is modified to comprise an acetyl group, a fluorenylmethoxy carbonyl group, a formyl group, a palmitoyl group, a myristyl group, a stearyl group, or polyethylene glycol, and a pharmaceutically acceptable carrier.

5. The method of claim 4 , wherein the subject is obese or has a traumatic brain injury, type 2 diabetes, hypertension, microvascular angiopathy, painful neuropathy, Parkinson's disease, dementia, major depressive disorder, schizophrenia, retinitis pigmentosa, refractory hypertension, mild cognitive dysfunction, primary open angle glaucoma or previously had a stroke or a traumatic brain injury or a combination thereof.

6. The method of claim 4 , wherein the subject has one or more 5-HT2A receptor autoantibodies.

7. The method of claim 4 , wherein the administration of the therapeutically effective amount of the pharmaceutical composition promotes or induces weight loss in the subject.

8. The method of claim 4 , further comprising administering a therapeutically effective amount of ketanserin or volinanserin to the subject.

9. A method of competitively inhibiting the binding of 5-HT2A receptor autoantibodies to a second extracellular loop region of the 5-HT2A receptor, the method comprising: administering to a subject a therapeutically effective amount of a decoy peptide consisting of the amino acid sequence of SCLLADDN (SEQ ID NO: 2), wherein at least one amino acid residue of the decoy peptide is modified to comprise an acetyl group, a fluorenylmethoxy carbonyl group, a formyl group, a palmitoyl group, a myristyl group, a stearyl group, or polyethylene glycol.

10. The method of claim 9 , wherein the subject has one or more 5-HT2A receptor autoantibodies.

11. The method of claim 9 , wherein the subject is at risk for developing refractory hypertension, a neurologic disease or disorder or a microvascular disease or disorder.

12. The method of claim 11 , wherein the neurologic disease or disorder is open angle glaucoma, dementia, Parkinson's disease, macular degeneration, or retinal degeneration, and wherein the microvascular disease or disorder is a stroke, kidney dysfunction, kidney failure, age-related macular degeneration, diabetic macular edema, diabetic nephropathy, microvascular angiopathy, hypertension, painful neuropathy, or hypertensive nephropathy.

13. The method of claim 9 , wherein the subject has type 2 diabetes, microvascular angiopathy, diabetic kidney disease, Parkinson's disease, dementia, major depressive disorder, obesity, refractory hypertension, essential hypertension or has had a stroke or a traumatic brain injury or a combination thereof.

14. The method of claim 9 , further comprising administering a therapeutically effective amount of ketanserin or volinanserin to the subject.