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Abrupt Reoxygenation of Microvascular Endothelial Cells After Hypoxia Activates ERK1/2 and JNK1, Leading to NADPH Oxidase‐Dependent Oxidant Production
Author(s) -
YU GUO,
PENG TIANQING,
FENG QINGPING,
TYML KAREL
Publication year - 2007
Publication title -
microcirculation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.793
H-Index - 83
eISSN - 1549-8719
pISSN - 1073-9688
DOI - 10.1080/10739680601131218
Subject(s) - nadph oxidase , p38 mitogen activated protein kinases , mapk/erk pathway , tyrosine phosphorylation , phosphorylation , kinase , reactive oxygen species , microbiology and biotechnology , hypoxia (environmental) , mitochondrial ros , protein kinase a , protein kinase c , chemistry , biology , oxygen , organic chemistry
ABSTRACT Objective: Mitogen‐activated protein kinases (MAPK) in microvascular endothelial cells (EC) may participate in organ pathophysiology following hypoxia/reoxygenation (H/R). The authors aimed to determine the role of MAPK in H/R‐induced reactive oxygen species (ROS) generation in mouse microvascular EC. Methods: Cultured EC derived from skeletal muscle of male wild‐type (WT), gp91phox −/− or p47phox −/− mice were subjected to hypoxia (0.1% O 2 , 1 h) followed by abrupt reoxygenation, H/R A (hypoxic medium quickly replaced by normoxic medium), or slow reoxygenation, H/R S (O 2 diffused to cells through hypoxic medium). Cells were analyzed for ERK, JNK, and p38 MAPK phosphorylation, NADPH oxidase activation, and ROS generation. Results: In WT cells, H/R A but not H/R S rapidly phosphorylated ERK1/2 and JNK1 and subsequently increased ROS production. H/R A did not affect p38. MAPK phosphorylation persisted despite inhibition of NADPH oxidase, mitochondrial respiration, protein tyrosine kinase, or PKC. ROS increase during H/R A was prevented by deletion of gp91phox or p47phox, or MAPK inhibition. Conclusions: Abrupt reoxygenation after hypoxia activates ERK1/2 and JNK1 in mouse microvascular endothelial cells via a tyrosine kinase‐, PKC‐, and NADPH oxidase‐insensitive mechanism, leading to increased NADPH oxidase‐dependent ROS production. The results suggest that MAPK activation in the microvascular endothelium is O 2 ‐sensitive, contributing critically to tissue pathophysiology after H/R.