Pseudhymenochirin-1Pb (Ps-1Pb; IKIPSFFRNILKKVGKEAVSLIAGALKQS) and pseudhymenochirin-2Pa (Ps-2Pa; GIFPIFAKLLGKVIKVASSLISKGRTE) are amphibian peptides with broad spectrum antimicrobial activities and cytotoxicity against mammalian cells. In the membrane-mimetic solvent 50% (v/v) trifluoroethanol-H2O, both peptides adopt a well-defined α-helical conformation that extends over almost all the sequence and incorporates a flexible bend. Both peptides significantly (p < 0.05) stimulate the rate of release of insulin from BRIN-BD11 clonal β-cells at concentrations ≥ 0.1 nM but produce loss of integrity of the plasma membrane at concentrations ≥ 1 ΜM. Increasing cationicity by the substitution Glu17' l-Lys in Ps-1Pb and Glu27' l-Lys in Ps-2Pa generates analogues with increased cytotoxicity and reduced insulin-releasing potency. In contrast, the analogues [R8r]Ps-1Pb and [K8k,K19k]Ps-2Pa, incorporating d-amino acid residues to destabilize the α-helical domains, retain potent insulin-releasing activity but are nontoxic to BRIN-BD11 cells at concentrations of 3 ΜM. [R8r]Ps-1Pb produces a significant increase in insulin release rate at 0.3 nM and [K8k,K19k]Ps-2Pa at 0.01 nM. Both analogues show low hemolytic activity (IC50 > 100 ΜM) but retain broad-spectrum antimicrobial activity and remain cytotoxic to a range of human tumor cell lines, albeit with lower potency than the naturally occurring peptides. These analogues show potential for development into agents for type 2 diabetes therapy.

Conformational analysis of the host-defense peptidespPseudhymenochirin-1Pb and -2Pa and design of analogues with insulin-releasing activities and reduced toxicities

SCORCIAPINO, MARIANO ANDREA;RINALDI, ANDREA;CASU, MARIANO;
2015

Abstract

Pseudhymenochirin-1Pb (Ps-1Pb; IKIPSFFRNILKKVGKEAVSLIAGALKQS) and pseudhymenochirin-2Pa (Ps-2Pa; GIFPIFAKLLGKVIKVASSLISKGRTE) are amphibian peptides with broad spectrum antimicrobial activities and cytotoxicity against mammalian cells. In the membrane-mimetic solvent 50% (v/v) trifluoroethanol-H2O, both peptides adopt a well-defined α-helical conformation that extends over almost all the sequence and incorporates a flexible bend. Both peptides significantly (p < 0.05) stimulate the rate of release of insulin from BRIN-BD11 clonal β-cells at concentrations ≥ 0.1 nM but produce loss of integrity of the plasma membrane at concentrations ≥ 1 ΜM. Increasing cationicity by the substitution Glu17' l-Lys in Ps-1Pb and Glu27' l-Lys in Ps-2Pa generates analogues with increased cytotoxicity and reduced insulin-releasing potency. In contrast, the analogues [R8r]Ps-1Pb and [K8k,K19k]Ps-2Pa, incorporating d-amino acid residues to destabilize the α-helical domains, retain potent insulin-releasing activity but are nontoxic to BRIN-BD11 cells at concentrations of 3 ΜM. [R8r]Ps-1Pb produces a significant increase in insulin release rate at 0.3 nM and [K8k,K19k]Ps-2Pa at 0.01 nM. Both analogues show low hemolytic activity (IC50 > 100 ΜM) but retain broad-spectrum antimicrobial activity and remain cytotoxic to a range of human tumor cell lines, albeit with lower potency than the naturally occurring peptides. These analogues show potential for development into agents for type 2 diabetes therapy.
Amino acid sequence; Amphibian proteins; Animals; Antimicrobial cationic peptides; Cell line, tumor; Diabetes mellitus, type 2; Humans; Insulin; Microbial sensitivity tests; Molecular structure; Nuclear magnetic resonance, Biomolecular; Drug discovery; Pharmaceutical science; Pharmacology; Analytical chemistry; Organic chemistry; Molecular medicine; Complementary and alternative medicine; Dermatology; Medicine (all)
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11584/168843
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