SOD2 and pulmonary arterial hypertension: For example, epigenetic methylation and downregulation of SOD2 by DNA methyltransferases in PAH (in the fawn hooded rat model of PAH) reduces H2O2-mediated signaling, mimicking the redox state seen in chronic hypoxia and eliciting PH that is characterized by medial thickening of the small pulmonary arteries and RVH (Bonnet et al., 2006; Archer et al., 2010a).