Loss of family with sequence similarity 13, member A exacerbates pulmonary hypertension through accelerating endothelial-to-mesenchymal transition.

Pulmonary hypertension is a progressive lung disease with poor prognosis due to the consequent right heart ventricular failure. Pulmonary artery remodeling and dysfunction are culprits for pathologically increased pulmonary arterial pressure, but their underlying molecular mechanisms remain to be elucidated. Previous genome-wide association studies revealed a significant correlation between the genetic locus of family with sequence similarity 13, member A (FAM13A) and various lung diseases such as chronic obstructive pulmonary disease and pulmonary fibrosis; however whether FAM13A is also involved in the pathogenesis of pulmonary hypertension remained unknown. Here, we identified a significant role of FAM13A in the development of pulmonary hypertension. FAM13A expression was reduced in the lungs of mice with hypoxia-induced pulmonary hypertension. We identified that FAM13A was expressed in lung vasculatures, especially in endothelial cells. Genetic loss of FAM13A exacerbated pulmonary hypertension in mice exposed to chronic hypoxia in association with deteriorated pulmonary artery remodeling. Mechanistically, FAM13A decelerated endothelial-to-mesenchymal transition potentially by inhibiting β-catenin signaling in pulmonary artery endothelial cells. Our data revealed a protective role of FAM13A in the development of pulmonary hypertension, and therefore increasing and/or preserving FAM13A expression in pulmonary artery endothelial cells is an attractive therapeutic strategy for the treatment of pulmonary hypertension.