title: Mitochondria-specific transgenic overexpression of phospholipid hydroperoxide glutathione peroxidase (GPx4) attenuates ischemia/reperfusion-associated cardiac dysfunction.
abstract: Ischemia/reperfusion (I/R) injury elicits damage to mitochondria. Antioxidants provide protection from I/R-induced mitochondrial damage. The goal of this study was to determine the impact of mitochondria-specific overexpression of GPx4 (PHGPx) on cardiac function following I/R. Transgenic mice were created in which PHGPx was overexpressed solely in the mitochondrion (mPHGPx). MPHGPx and littermate control hearts were subjected to global no-flow ischemia (20 min) followed by reflow reperfusion (30, 60, and 90 min). Following I/R, mPHGPx hearts possessed significantly better rates of contraction, developed pressures, and peak-systolic pressures as compared to controls (P<0.05). No differences were observed in rates of relaxation or end-diastolic pressures. Lipid peroxidation was significantly lower in mitochondria from mPHGPx hearts as compared to controls, following I/R (P<0.05). Electron transport chain (ETC) complex I, III, and IV activities were significantly higher in mPHGPx hearts as compared to controls, following I/R (P<0.05). MPHGPx overexpression enhanced ETC complex I, III, and IV activities in subsarcolemmal mitochondria (SSM; P<0.05), and ETC complex I and III activities in interfibrillar mitochondria (IFM; P<0.05) following I/R. These results indicate that mitochondria-specific GPx4 overexpression protects cardiac contractile function and preserves ETC complex activities following I/R. These results provide further rationale for the use of mPHGPx as a therapeutic protectant.
authors.affiliation: West Virginia University School of Medicine, Division of Exercise Physiology, and Center for Interdisciplinary Research in Cardiovascular Sciences, 1 Medical Center Drive, Morgantown, WV 26506, USA.
authors.forename: Erinne R
authors.initials: ER
authors.lastname: Dabkowski
authors.forename: Courtney L
authors.initials: CL
authors.lastname: Williamson
authors.forename: John M
authors.initials: JM
authors.lastname: Hollander
mesh_terms: D000818:Animals; D005979:Glutathione Peroxidase / Q000235:genetics / Q000378:metabolism*; D006333:Heart Failure / Q000150:complications* / Q000473:pathology; D015227:Lipid Peroxidation; D051379:Mice; D008822:Mice, Transgenic; D008928:Mitochondria / Q000201:enzymology*; D009336:Necrosis; D000080662:Phospholipid Hydroperoxide Glutathione Peroxidase; D015427:Reperfusion Injury / Q000150:complications / Q000517:prevention & control*
chemical_list: D000080662:Phospholipid Hydroperoxide Glutathione Peroxidase; D005979:Glutathione Peroxidase