title: Cleavage of mitogen-activated protein kinases in human neutrophils undergoing apoptosis: role in decreased responsiveness to inflammatory cytokines.
abstract: Extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) are major signaling molecules activated in human neutrophils stimulated by cytokines. Both molecules were cleaved at the N-terminal portion in neutrophils undergoing apoptosis induced by in vitro culture alone or treatment with TNF and/or cycloheximide. The cleavage of both molecules was inhibited by G-CSF and benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone, a caspase inhibitor, both of which can inhibit neutrophil apoptosis. In a cell-free system, ERK and p38 MAPK were not cleaved by recombinant caspase-3 or caspase-8 while gelsolin was cleaved by caspase-3 under the same condition. The cleavage of both molecules appears to be specific to mature neutrophils, since it was not detected in immature cells (HL-60 and Jurkat) undergoing apoptosis, indicating that proteases responsible for the cleavage of both molecules may develop during differentiation into mature neutrophils. Concomitant with the cleavage of ERK and p38 MAPK, GM-CSF- and TNF-induced superoxide release, adherence, and phosphorylation of ERK and p38 MAPK were decreased in neutrophils undergoing apoptosis. In addition, GM-CSF- and TNF-induced superoxide release and adherence were inhibited by PD98059 MAPK/ERK kinase inhibitor) as well as SB203580 (p38 MAPK inhibitor), suggesting possible involvement of ERK and p38 MAPK in superoxide release and adherence induced by these cytokines. These findings indicate that ERK and p38 MAPK are cleaved and degraded in neutrophils undergoing apoptosis in a caspase-dependent manner and the cleavage of both molecules may be partly responsible for decreased functional responsiveness to inflammatory cytokines.
authors.affiliation: Departments of. Physiology and Clinical Hematology, Osaka City University Medical School, Asahi-machi, Abeno-ku, Osaka, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Suzuki
authors.forename: T
authors.initials: T
authors.lastname: Hasegawa
authors.forename: C
authors.initials: C
authors.lastname: Sakamoto
authors.forename: Y M
authors.initials: YM
authors.lastname: Zhou
authors.forename: F
authors.initials: F
authors.lastname: Hato
authors.forename: M
authors.initials: M
authors.lastname: Hino
authors.forename: N
authors.initials: N
authors.lastname: Tatsumi
authors.forename: S
authors.initials: S
authors.lastname: Kitagawa
mesh_terms: D000328:Adult; D017209:Apoptosis / Q000187:drug effects / Q000276:immunology*; D020169:Caspases / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects / Q000276:immunology; D002470:Cell Survival / Q000187:drug effects / Q000276:immunology; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D016207:Cytokines / Q000502:physiology*; D053938:DNA Fragmentation / Q000187:drug effects / Q000276:immunology; D004306:Dose-Response Relationship, Immunologic; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D018922:HL-60 Cells; D006801:Humans; D006868:Hydrolysis; D007093:Imidazoles / Q000494:pharmacology; D007249:Inflammation / Q000201:enzymology / Q000276:immunology; D019169:Jurkat Cells; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009504:Neutrophils / Q000201:enzymology* / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D011725:Pyridines / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D016207:Cytokines; D004791:Enzyme Inhibitors; D005419:Flavonoids; D007093:Imidazoles; D011725:Pyridines; D014409:Tumor Necrosis Factor-alpha; D013481:Superoxides; D016179:Granulocyte Colony-Stimulating Factor; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D003513:Cycloheximide; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D020169:Caspases; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one