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Mitochondrial respiratory chain complex‐III is involved in BAK (BH3)‐mediated ROS generation and microvascular endothelial cell hyperpermeability
Author(s) -
Childs Ed W,
Tharakan Binu,
Hunter Felicia A,
Isong Mfon,
Liggins Nichole D
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1219-b
Subject(s) - cytochrome c , microbiology and biotechnology , reactive oxygen species , mitochondrial ros , chemistry , antimycin a , mitochondrion , endothelial stem cell , apoptosis , vascular permeability , biochemistry , biology , in vitro , endocrinology
Endothelial cell disruption following ischemia‐reperfusion (IR) has been shown to increase vascular hyperpermeability. We hypothesized that mitochondrial ROS mediates vascular permeability in endothelial cells by activating proapoptotic pathways. The purpose of this study was to identify specific site(s) of ROS production in mitochondrial electron transport chain complexes in rat lung microvascular endothelial cells (RLMEC) and their role in microvascular hyperpermeability. RLMEC grown on Transwell membranes as monolayers were treated with inhibitors of the complexes (I–V) or inhibitors of various enzymes followed by proapoptotic BAK (BH3) peptide transfection. The permeability changes were determined based on FITC‐albumin flux across the monolayer. ROS production was determined by using H 2 DCF‐DA. Cytochrome c levels were measured by ELISA. BAK (BH3) transfection induced ROS generation, cytochrome c release and hyperpermeability ( p < 0.05). Complex‐III inhibitor antimycin A attenuated BAK (BH3)‐induced ROS production and hyperpermeability ( p < 0.05). Inhibitors of the other complexes (I, II, IV, V) or enzymes were ineffective. Further, antimycin A inhibited BAK (BH3)‐induced cytochrome c release. This suggests complex‐III as a major site of ROS generation that regulates vascular permeability in RLMEC through cytochrome c ‐induced apoptotic signaling cascade.