Up-regulation of cullin7 promotes proliferation and migration of pulmonary artery smooth muscle cells in hypoxia-induced pulmonary hypertension

It has well been demonstrated that E3 ubiquitin ligase cullin7 plays important roles in cancer cell growth control via down-regulating p53 expression. The noncanonical function or the pathogenic role of p53 has more recently been implicated in pulmonary vascular remodeling. Therefore, whether cullin7 participates in hypoxia-induced pulmonary vascular remodeling deserves to be elucidated. The present study found that hypoxia up-regulated the expression of cullin7 mRNA and protein in pulmonary arteries and pulmonary artery smooth muscle cells, and knockdown of cullin7 inhibited hypoxia-induced proliferation and migration of pulmonary artery smooth muscle cells and reversed hypoxia-induced inhibition of p53 expression. Notably, administration of proteasome inhibitor MG132 significantly inhibited the expression of cullin7 and up-regulated the expression of p53 in pulmonary arteries concomitantly with improvement of hypoxia-induced pulmonary vascular remodeling. Our study demonstrated that hypoxia induced up-regulation of cullin7 expression resulting to the proliferation and migration of pulmonary artery smooth muscle cells via down-regulating p53 expression, which contributed to pulmonary vascular remodeling.