USP3 and pulmonary arterial hypertension: In this study, we first explored the expression of microRNA-146-5p and USP3 and the interaction between them in pulmonary artery smooth muscle cells under hypoxia conditions, so as to clarify the impacts of microRNA-146-5p and USP3 in the progression and formation of PAH, which may provide a new target for the diagnosis and treatment of PAH.