We previously reported that EC-SOD activity is impaired following exposure to chronic hypoxia, and overexpression of lung EC-SOD in two murine models of pulmonary hypertension protected against pulmonary vascular remodeling and prevented the early upregulation of the redox sensitive transcription factor, Egr-1 [10], [11]. The gene discussed is SOD1; the disease is pulmonary arterial hypertension.