title: Insulin-releasing properties of the frog skin peptide pseudin-2 and its [Lys18]-substituted analogue.
abstract: Abstract Pseudin-2 is a cationic alpha-helical peptide that was first isolated from the skin of the paradoxical frog Pseudis paradoxa on the basis of its antimicrobial activity. We have investigated the insulin-releasing properties and cytotoxicity of the peptide, together with selected analogues with increased cationicity and hydrophobicity. At concentrations in the range 10(-9)-10(-6) m, pseudin-2, and its [Lys18], [Phe8], and [d-Lys3,d-Lys10,d-Lys14] derivatives, stimulated insulin release from the BRIN-BD11 clonal beta-cell line without increasing release of lactate dehydrogenase. The [Lys18] analogue was the most potent (46% increase in insulin release at 10(-9) m) and the most effective (215% increase in insulin release at 10(-6) m). The more cationic [Lys3,Lys10,Lys14] and [Lys3,Lys10,Lys14,Lys21] analogues lacked insulinotropic action and the more hydrophobic [Phe16] analogue was cytotoxic at concentrations > or =10(-7) m. Pseudin-2 and [Lys18]-pseudin-2 had no effect on intracellular calcium concentrations and stimulated insulin release in the absence of external calcium. [Lys18]-pseudin-2 (10(-8) m) stimulated insulin release in the presence of diazoxide and verapamil. Our results demonstrate that pseudin-2 stimulates insulin secretion from BRIN-BD11 cells by a mechanism involving Ca2+-independent pathways and identify [Lys18]-pseudin-2 as a peptide that may have potential for development as a therapeutically valuable insulinotropic agent for the treatment of type 2 diabetes.
authors.affiliation: School of Biomedical Sciences, University of Ulster, Cromore Road, Coleraine BT52 1SA, UK.
authors.forename: Yasser H A
authors.initials: YH
authors.lastname: Abdel-Wahab
authors.forename: Gavin J
authors.initials: GJ
authors.lastname: Power
authors.forename: Ming T
authors.initials: MT
authors.lastname: Ng
authors.forename: Peter R
authors.initials: PR
authors.lastname: Flatt
authors.forename: J Michael
authors.initials: JM
authors.lastname: Conlon
mesh_terms: D029845:Amphibian Proteins / Q000737:chemistry* / Q000494:pharmacology*; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry* / Q000494:pharmacology*; D002118:Calcium; D002412:Cations; D002460:Cell Line; D057927:Hydrophobic and Hydrophilic Interactions; D007004:Hypoglycemic Agents / Q000737:chemistry* / Q000494:pharmacology; D007328:Insulin / Q000819:agonists* / Q000378:metabolism; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000187:drug effects / Q000378:metabolism; D011898:Ranidae; D012867:Skin; D013329:Structure-Activity Relationship
chemical_list: D029845:Amphibian Proteins; D023181:Antimicrobial Cationic Peptides; D002412:Cations; D007004:Hypoglycemic Agents; D007328:Insulin; C441477:pseudin-2 protein, Pseudis paradoxa; D002118:Calcium