NOS2 and pulmonary arterial hypertension: This paper explores the roles of NOS and nitrate/nitrite-mediated protein S-nitrosylation in heart diseases, including systemic hypertension, PAH, atherosclerosis, heart failure, myocardial infarction, arrhythmia, and diabetic cardiomyopathy, and examines the potential of S-nitrosylation regulation as a novel therapeutic strategy, offering new insights into the treatment of heart diseases and the development of drugs targeting S-nitrosylation.