title: Synthetic peptide VKGFY and its cyclic analog stimulate macrophage bactericidal activity through non-opioid beta-endorphin receptors.
abstract: We synthesized linear and cyclic pentapeptides corresponding to the sequence 369-373 of human immunoglobulin G heavy chain--VKGFY (referred to as pentarphin and cyclopentarphin, respectively). The effect of pentarphin and cyclopentarphin on phagocytosis of Salmonella typhimurium virulent 415 strainbacteria by mouse peritoneal macrophages in vitro was studied. Control experiments showed that macrophages actively captured these bacteria, but did not digest them: the captured microbes were viable and continued to proliferate inside the phagocytes; within 12 h all macrophage monolayer was destroyed (incomplete phagocytosis). If 1 nM pentarphin or cyclopentarphin was added to the cultivation medium, macrophage bactericidal activity was significantly increased and they digested all captured microorganisms within 6 h (complete phagocytosis). To study the receptor binding properties of pentarphin and cyclopentarphin we prepared (125)I-labeled pentarphin (179 Ci/mmol specific activity). The binding of (125)I-labeled pentarphin to mouse peritoneal macrophages was high-affinity (K(d) = 3.6 +/- 0.3 nM) and saturable. Studies on binding specificity revealed that this binding was insensitive to naloxone and [Met(5)]enkephalin, but completely inhibited by unlabeled cyclopentarphin (K(i) = 2.6 +/- 0.3 nM), immunorphin (K(i) = 3.2 +/- 0.3 nM), and beta-endorphin (K(i) = 2.8 +/- 0.2 nM). Thus, the effects of pentarphin and cyclopentarphin on macrophages are mediated by naloxone-insensitive receptors common for pentarphin, cyclopentarphin, immunorphin, and beta-endorphin.
authors.affiliation: Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia. navolots@fibkh.serpukhov.su
authors.forename: E V
authors.initials: EV
authors.lastname: Navolotskaya
authors.forename: A A
authors.initials: AA
authors.lastname: Kolobov
authors.forename: E A
authors.initials: EA
authors.lastname: Kampe-Nemm
authors.forename: T A
authors.initials: TA
authors.lastname: Zargarova
authors.forename: N V
authors.initials: NV
authors.lastname: Malkova
authors.forename: S B
authors.initials: SB
authors.lastname: Krasnova
authors.forename: Yu A
authors.initials: YA
authors.lastname: Kovalitskaya
authors.forename: V P
authors.initials: VP
authors.lastname: Zav'yalov
authors.forename: V M
authors.initials: VM
authors.lastname: Lipkin
mesh_terms: D000818:Animals; D007456:Iodine Isotopes; D008262:Macrophage Activation / Q000187:drug effects*; D017737:Macrophages, Peritoneal / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D051379:Mice; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists; D009842:Oligopeptides / Q000037:antagonists & inhibitors / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology*; D010456:Peptides, Cyclic / Q000037:antagonists & inhibitors / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology*; D010587:Phagocytosis / Q000187:drug effects*; D011957:Receptors, Opioid / Q000378:metabolism*; D012486:Salmonella typhimurium / Q000276:immunology; D014405:Tuftsin / Q000494:pharmacology
chemical_list: D007456:Iodine Isotopes; D009292:Narcotic Antagonists; D009842:Oligopeptides; D010456:Peptides, Cyclic; D011957:Receptors, Opioid; C474114:valyl-lysyl-glycyl-phenylalanyl-tyrosine; D009270:Naloxone; D014405:Tuftsin