Splitomicin inhibits fMLP-induced superoxide anion production in human neutrophils by activate cAMP/PKA signaling inhibition of ERK pathway.
Splitomicin, is a cell-permeable lactone derived from naphthol and known to be a potent selective inhibitor of Sir2 (silent information regulator 2). Previous studies have demonstrated that naphtholic compounds possess an inhibitory effect on neutrophils. Here, we present our investigation on the inhibitory effects of splitomicin in human neutrophils. The primary goal of our study was to locate a possible candidate on inflammatory reactions and to hopefully develop a novel anti-inflammatory therapy. Neutrophils were prepared following standard procedures. Neutrophils induced by either fMLP (1 μM) or PMA (100 nM) were observed using a flow cytometer and the intracellular production of superoxide anions was investigated at different splitomicin concentrations. The cytosolic Ca(++) influx concentration was measured using a fluorescence spectrophotometer, and Mac-1 expression was detected with a flow cytometer. The MAP kinases were measured using western blotting. Our results showed that splitomicin inhibited superoxide anion production by fMLP (1 μM) and NaF (20mM) in a concentration-dependent manner (37.5-450 μM). Splitomicin (300 and 450 μM) also suppressed fMLP-induced intracellular calcium ion mobilization and extracellular-signal regulated kinase (ERK) phosphorylation. Moreover, splitomicin could inhibit fMLP-induced Mac-1 expression and increase cAMP levels in human neutrophils. Our data demonstrated that splitomicin exhibits a noticeable inhibitory effect on superoxide anion production in human neutrophils. This negative effect was well-correlated with increased cAMP levels via PKA activity and the subsequent inhibition of ERK (p42/p44) phosphorylation to decrease superoxide anion production.
Department of Anesthesiology, Chang Gung Memorial Hospital, Linkou, Taiwan, ROC.
Fu-Chao
FC
Liu
Yuan-Ji
YJ
Day
Jiin-Tarng
JT
Liou
Huang-Ping
HP
Yu
Hsiang-Ruei
HR
Liao
D000328:Adult; D000527:Alprostadil / Q000494:pharmacology; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D009281:Naphthalenes / Q000494:pharmacology*; D009504:Neutrophils / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011753:Pyrones / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects*; D013481:Superoxides / Q000378:metabolism*; D055815:Young Adult
D000893:Anti-Inflammatory Agents; D009281:Naphthalenes; D047428:Protein Kinase Inhibitors; D011753:Pyrones; D013481:Superoxides; C444426:splitomicin; D009240:N-Formylmethionine Leucyl-Phenylalanine; D006861:Hydrogen Peroxide; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D000527:Alprostadil; D004121:Dimethyl Sulfoxide