Inhibitory effects of spinorphin, a novel endogenous regulator, on chemotaxis, O2- generation, and exocytosis by N-formylmethionyl-leucyl-phenylalanine (FMLP)-stimulated neutrophils.
To characterize the inflammatory effect of spinorphin, an endogenous peptide purified from bovine spinal cord, its effects on chemotaxis, O2- generation, and exocytosis by N-formylmethionyl-leucyl-phenylalanine (FMLP)-stimulated human neutrophils (PMNs) in vitro were examined. At 10 microM, spinorphin significantly inhibited chemotaxis by FMLP-stimulated PMNs. Spinorphin at 100 microM also inhibited both O2- generation and exocytosis of beta-glucuronidase and collagenase by FMLP-stimulated PMNs. The mechanisms by which spinorphin inhibits these PMN functions were examined further. Spinorphin markedly suppressed the binding of FML[3H]P to its receptor on PMNs, as observed in a binding assay. However, other neuropeptides that were examined (angiotensin II and substance P) had no effect on FML[3H]P binding, suggesting the possibility that spinorphin plays a specific role in the inhibition of the binding between FMLP and its receptor. The suppression of FMLP binding also caused a decrease of the FMLP-induced intracellular calcium concentration [Ca2+]i, which acts as a second messenger leading to PMN functions. These results suggest that spinorphin may be a new endogenous inflammation-regulatory peptide that modulates the interaction of FMLP with its receptor.
Yamamoto
Y
Y
Department of Cancer Therapeutics, The Tokyo Metropolitan Institute of Medical Science, Japan. yyamamoto@rinshoken.or.jp
Kanazawa
T
T
Shimamura
M
M
Ueki
M
M
Hazato
T
T
D018826:CD13 Antigens / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002633:Chemotaxis / Q000187:drug effects*; D005089:Exocytosis / Q000187:drug effects*; D006801:Humans; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000494:pharmacology; D015260:Neprilysin / Q000378:metabolism; D018375:Neutrophil Activation / Q000187:drug effects; D009504:Neutrophils / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D009842:Oligopeptides / Q000494:pharmacology*; D011480:Protease Inhibitors / Q000494:pharmacology; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic / Q000187:drug effects / Q000378:metabolism; D018000:Receptors, Peptide / Q000187:drug effects / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism*
D009842:Oligopeptides; D011480:Protease Inhibitors; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic; D018000:Receptors, Peptide; D013481:Superoxides; C082392:spinorphin; D009240:N-Formylmethionine Leucyl-Phenylalanine; D018826:CD13 Antigens; D015260:Neprilysin; D002118:Calcium