Hyperoxia synergizes with mutant bone morphogenic protein receptor 2 to cause metabolic stress, oxidant injury, and pulmonary hypertension.

Fessel JP, Flynn CR, Robinson LJ, Penner NL, Gladson S, Kang CJ, Wasserman DH, Hemnes AR, West JD
Am J Respir Cell Mol Biol. 2013 49 (5): 778-87

PMID: 23742019 · PMCID: PMC3931097 · DOI:10.1165/rcmb.2012-0463OC

Pulmonary arterial hypertension (PAH) has been associated with a number of different but interrelated pathogenic mechanisms. Metabolic and oxidative stresses have been shown to play important pathogenic roles in a variety of model systems. However, many of these relationships remain at the level of association. We sought to establish a direct role for metabolic stress and oxidant injury in the pathogenesis of PAH. Mice that universally express a disease-causing mutation in bone morphogenic protein receptor 2 (Bmpr2) were exposed to room air or to brief daily hyperoxia (95% oxygen for 3 h) for 6 weeks, and were compared with wild-type animals undergoing identical exposures. In both murine tissues and cultured endothelial cells, the expression of mutant Bmpr2 was sufficient to cause oxidant injury that was particularly pronounced in mitochondrial membranes. With the enhancement of mitochondrial generation of reactive oxygen species by hyperoxia, oxidant injury was substantially enhanced in mitochondrial membranes, even in tissues distant from the lung. Hyperoxia, despite its vasodilatory actions in the pulmonary circulation, significantly worsened the PAH phenotype (elevated right ventricular systolic pressure, decreased cardiac output, and increased pulmonary vascular occlusion) in Bmpr2 mutant animals. These experiments demonstrate that oxidant injury and metabolic stress contribute directly to disease development, and provide further evidence for PAH as a systemic disease with life-limiting cardiopulmonary manifestations.

MeSH Terms (24)

Animals Arterial Pressure Bone Morphogenetic Protein Receptors, Type II Cardiac Output Cell Line, Tumor Disease Models, Animal Endothelial Cells Familial Primary Pulmonary Hypertension Humans Hyperoxia Hypertension, Pulmonary Lung Lung Injury Mice Mice, Transgenic Mitochondria Mitochondrial Membranes Mutation Oxidative Stress Pulmonary Artery Reactive Oxygen Species Stress, Physiological Ventricular Function, Right Ventricular Pressure

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