title: Phe-D-Leu-Phe-D-Leu-Phe derivatives as formylpeptide receptor antagonists in human neutrophils: cellular and conformational aspects.
abstract: We synthesized several Phe-d-Leu-Phe-d-Leu-Phe analogues in which tert-butyloxycarbonyl and four different ureido substituents were included at the N-terminal of the peptides, obtained as free acid and methyl-ester derivatives. Their biological action was analysed on human neutrophil responses induced by N-formyl-Met-Leu-Phe (fMLF). Several in vitro assays were carried out: receptor binding, measurement of Ca2+ intracellular concentration, chemotaxis, superoxide anion production and enzyme release. A conformational investigation, using infrared absorption and circular dichroism, was also performed. Our results demonstrate that the compounds examined prefer an ordered conformation (beta-turn) in amphipathic environment, and are able to antagonize the neutrophil functions evoked by fMLF. Moreover, the extent of inhibition of Ca2+ intracellular enhancement, as well as of superoxide anion production and granule enzyme release, appears related to their affinity toward the formylpeptide receptor. The free acid peptide derivatives appear to be more active antagonists than the methyl-ester ones.
authors.affiliation: Department of Pharmaceutical Sciences, via Fossato di Mortara 19, Ferrara University, 44100, Ferrara, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Dalpiaz
authors.forename: M E
authors.initials: ME
authors.lastname: Ferretti
authors.forename: R
authors.initials: R
authors.lastname: Pecoraro
authors.forename: E
authors.initials: E
authors.lastname: Fabbri
authors.forename: S
authors.initials: S
authors.lastname: Traniello
authors.forename: A
authors.initials: A
authors.lastname: Scatturin
authors.forename: S
authors.initials: S
authors.lastname: Spisani
mesh_terms: D001667:Binding, Competitive; D002118:Calcium / Q000378:metabolism; D002942:Circular Dichroism; D006801:Humans; D015394:Molecular Structure; D009113:Muramidase / Q000378:metabolism; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000037:antagonists & inhibitors; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D009842:Oligopeptides / Q000138:chemical synthesis / Q000494:pharmacology*; D011487:Protein Conformation; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic / Q000037:antagonists & inhibitors*; D018000:Receptors, Peptide / Q000037:antagonists & inhibitors*; D017550:Spectroscopy, Fourier Transform Infrared; D013481:Superoxides / Q000378:metabolism
chemical_list: D009842:Oligopeptides; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic; D018000:Receptors, Peptide; D013481:Superoxides; D009240:N-Formylmethionine Leucyl-Phenylalanine; D009113:Muramidase; D002118:Calcium