Hypochlorous acid stimulation of the mitogen-activated protein kinase pathway enhances cell survival.
We investigated the activation of three subfamilies of mitogen-activated protein kinases (MAP kinase), the extracellular regulated kinase (ERK1/2), p38, and c-Jun N-terminal kinase (JNK), by the myeloperoxidase-derived oxidant HOCl, in human umbilical vein endothelial cells (HUVEC) and human skin fibroblasts. Treatment of fibroblasts with 10-30 microM HOCl induced a dose-dependent increase in the tyrosine phosphorylation of several proteins. ERK1/2 was activated by exposure to sublethal concentrations of reagent HOCl or by HOCl generated by myeloperoxidase as shown by immune complex kinase assays. Maximum activation was seen at 20 microM and peak activation occurred within 10 min. Western blot analysis demonstrated activation of p38 with 30 microM HOCl, occurring at 15-30 min. No activation of JNK was detected in the concentration range investigated. These results show that HOCl is able to activate MAP kinases. Effective doses were considerably lower than with H2O2 and the lack of JNK activation contrasts with the activation frequently seen with H2O2. Exposure to HOCl caused a loss of viability in HUVEC that was markedly enhanced when ERK1/2 activation was inhibited by U0126. This suggests that the activation of ERK promotes cell survival in response to the oxidative challenge.
Midwinter
R G
RG
Free Radical Research Group, Pathology Department, Christchurch School of Medicine, Christchurch, New Zealand. robyn.midwinter@chmeds.ac.nz
Vissers
M C
MC
Winterbourn
C C
CC
D016923:Cell Death / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002712:Chlorides / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology* / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D005347:Fibroblasts; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D006997:Hypochlorous Acid / Q000494:pharmacology*; D048031:JNK Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009195:Peroxidase / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D019000:Phosphotyrosine / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D014471:Umbilical Veins
D002712:Chlorides; D019000:Phosphotyrosine; D006997:Hypochlorous Acid; D006861:Hydrogen Peroxide; D009195:Peroxidase; D017346:Protein Serine-Threonine Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; C482125:MAP2K1 protein, human; D020929:Mitogen-Activated Protein Kinase Kinases