title: p38 MAPK associated with stereoselective priming by grepafloxacin on O2- production in neutrophils.
abstract: Grepafloxacin is an asymmetric fluoroquinolone derivative which possesses high tissue penetrability as well as strong, broad-spectrum antimicrobial activities. We recently found that grepafloxacin induced a priming effect on neutrophil respiratory burst induced by N-formylmethionylleucylphenylalanine. In this report, we elucidate the precise mechanism of the priming by grepafloxacin. The R(+) enantiomer of grepafloxacin induced a more potent priming effect than did S(-)-grepafloxacin. R(+)-Grepafloxacin also produced a more potent translocation of both p47- and p67-phox proteins to membrane fractions of neutrophils. Grepafloxacin-induced primed superoxide generation was significantly inhibited by pretreatment with PD169316 and SB203580, p38 mitogen-activated protein kinase (MAPK) inhibitors, but not with PD98059, a specific inhibitor of the upstream kinase that activates p44/42 MAPK, or SP600125, an inhibitor of stress-activated protein kinase/c-Jun N-terminal kinase (JNK). Grepafloxacin strongly phosphorylated p38 MAP kinase but not p44/42 MAPK or JNK. R(+)-Grepafloxacin showed more potent phosphorylation of p38 MAPK than did S(-)-grepafloxacin, in a time- and concentration-dependent manner. PD169316 significantly inhibited R(+)-grepafloxacin-induced translocation of p47-phox protein to the membrane fraction. Interestingly, grepafloxacin stereospecifically bound to the membrane fractions of neutrophils. These results strongly suggest that grepafloxacin stereospecifically primes neutrophil respiratory burst, and p38 MAPK activation is closely related to the grepafloxacin priming.
authors.affiliation: Medical Education Development Center, Gifu University School of Medicine, Gifu, Japan. mniwa@cc.gifu-u.ac.jp
authors.forename: Masayuki
authors.initials: M
authors.lastname: Niwa
authors.forename: Koichi
authors.initials: K
authors.lastname: Hotta
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kanamori
authors.forename: Masako
authors.initials: M
authors.lastname: Kumada
authors.forename: Masao
authors.initials: M
authors.lastname: Hirota
authors.forename: Osamu
authors.initials: O
authors.lastname: Kozawa
authors.forename: Sadaki
authors.initials: S
authors.lastname: Fujimoto
mesh_terms: D002462:Cell Membrane / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D024841:Fluoroquinolones / Q000494:pharmacology*; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D048670:MAP Kinase Kinase 4; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D019255:NADPH Oxidases; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D010879:Piperazines / Q000494:pharmacology*; D021381:Protein Transport; D016897:Respiratory Burst / Q000187:drug effects* / Q000502:physiology; D013237:Stereoisomerism; D013481:Superoxides / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D024841:Fluoroquinolones; D010750:Phosphoproteins; D010879:Piperazines; D013481:Superoxides; D009240:N-Formylmethionine Leucyl-Phenylalanine; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases; C075375:grepafloxacin