[Hypoxia stimulates the expression of HSP70 in pulmonary artery smooth muscle cells]

Hypoxic pulmonary hypertension is characterized by remodeling of pulmonary artery, proliferation and migration of pulmonary artery smooth muscle cells (PASMC), the mechanism of which was studied by observing the effect of hypoxia on DNA synthesis, cell cycle phase and transcription of heat shock protein 70 (HSP70). Our results indicate that hypoxia increases DNA synthesis, enhances the mitogenic effect of ET-1 on PASMC, stimulates quiescent PASMC entering S phase from G0/G1 phase and up-regulates the mRNA level of HSP70. Heat shock proteins are conservative and important stress proteins rendering the cells more tolerable to dangerous stresses by promoting growth and survival of the cells. All these findings suggest that heat shock proteins might also be important to the proliferation of PASMC induced by hypoxia and relevant to the study of the mechanism of hypoxic vascular remodeling.