In addition, miR-140-5p expression was reduced in rat models in vivo and in PAH patients, and knockdown of miR-140-5p could facilitate the expression of the E3 ubiquitin ligase SMURF1 and activate BMP signaling, thereby promoting PASMC proliferation and pulmonary artery endothelial dysfunction and possibly exacerbating PAH (113). Here, MUL1 is linked to pulmonary arterial hypertension.