| Leptin-based glycopeptide induces weight loss and simultaneously restores fertility in animal models. | |
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MedLine Citation:
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PMID: 20415687 Owner: NLM Status: In-Process |
Abstract/OtherAbstract:
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AIM: To design, manufacture and test a second generation leptin receptor (ObR) agonist glycopeptide derivative. The major drawback to current experimental therapies involving leptin protein is the appearance of treatment resistance. Our novel peptidomimetic was tested for efficacy and lack of resistance induction in rodent models of obesity and appetite reduction. METHODS: The glycopeptide containing two additional non-proteinogenic amino acids was synthesized by standard solid-phase methods. Normal mice were fed with peanuts until their blood laboratory data and liver histology showed typical signs of obesity but not diabetes. The mice were treated with the peptidomimetic at 0.02, 0.1 or 0.5 mg/kg/day intraperitoneally side-by-side with 0.1 mg/kg/day leptin for 11 days. After termination of the assay, the blood cholesterol and glucose amounts were measured, the liver fat content was visualized and quantified and the remaining mice returned to normal diet and were allowed to mate. In parallel experiments normal rats were treated intranasally with the glycopeptide at 0.1 mg/kg/day for 10 days. RESULTS: The 12-residue glycosylated leptin-based peptidomimetic E1/6-amino-hexanoic acid (Aca) was designed to target a principal leptin/ObR-binding interface. E1/Aca induced leptin effects in ObR-positive cell lines at picomolar concentrations and readily crossed the blood-brain barrier (BBB) following intraperitoneal administration. The peptide initiated typical leptin-dependent signal transduction pathways both in the presence and absence of leptin protein. The peptide also reduced weight gain in mice fed with high-fat peanut diet in a dose-dependent manner. Obese mice receiving peptide E1/Aca at a 0.5 mg/kg/day dose lost weight, corresponding to a net 6.5% total body weight loss, while similar mice treated with leptin protein did not. Upon cessation of the weight loss treatment, several obesity-related pathologies (i.e. abnormal metabolic profile and liver histology as well as infertility) normalized in peptide-, but not leptin-treated, mice. Peptide E1/Aca added intranasally to growing normal rats decelerated normal weight gain corresponding to a net 6.8% net total body weight loss with statistical significance. CONCLUSIONS: No resistance induction to peptide E1/Aca or toxicity in either obese or healthy rodents was observed, indicating the potential for widespread utility of the peptidomimetic in the treatment of leptin-deficiency disorders. We provide additional proof for the hypothesis that difficulties in current leptin therapies reside at the BBB penetration stage, and we document that by either glycosylation or intranasal peptide administration we can overcome this limitation. |
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Authors:
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I Kovalszky; E Surmacz; L Scolaro; M Cassone; R Ferla; A Sztodola; J Olah; M P D Hatfield; S Lovas; L Otvos |
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Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Diabetes, obesity & metabolism Volume: 12 ISSN: 1463-1326 ISO Abbreviation: Diabetes Obes Metab Publication Date: 2010 May |
Date Detail:
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Created Date: 2010-04-26 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 100883645 Medline TA: Diabetes Obes Metab Country: England |
Other Details:
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Languages: eng Pagination: 393-402 Citation Subset: IM |
Affiliation:
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1st Department of Pathology and Experimental Cancer Research, Semmelweis University Medical School, Budapest, Hungary. |
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Descriptor/Qualifier:
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| Grant Support | |
ID/Acronym/Agency:
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1 P20 RR16489/RR/NCRR NIH HHS |
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