Abstract: Objective To investigate the effects of integrin β1 within lipid raft on PMVECs. Methods PMVECs were divided into four groups: control group; HPS group: HPS; group and MβCD group: the cells were pretreated with 0.01 mol/L MβCD for 1 hour, and then cultured with HPS rat serum; si-integrin β1 group: construction of integrin β1 low expression cells using siRNA technology, and then cultured with HPS rat serum. The expression of integrin β1,FAK and pY397FAK in lipid rafts of PMVECs in each group was detected by Western blot; cell pro- liferation, migration were observed by CCK-8 and wound healing assay; the secretion of angiogenic factors (VEGF) was detected by ELISA. Results Compared with the control group, the expression of integrin β1 and the level of activated FAK in the lipid rafts of HPS group were higher than that of the control group(P＜0.05), PMVECs proliferation, migration and the level of secreted VEGF were significantly increased(P＜0.05). Compared with the HPS group, the expression of integrin β1 and the level of activated FAK in the lipid rafts were significantly reduced in the MβCD group or in siRNA integrin β1 group(P＜0.05), PMVECs proliferation, migration and secretion of VEGF were also significantly reduced(P＜0.05). Conclusions The up-regulation of integrin β1 within lipid raft activates integrin β1/FAK pathway thereby promotes cell proliferation, migration and secretion of VEGF, which may mediate pulmonary vascular remodeling of HPS.

Key words: hepatopulmonary syndrome(HPS), integrin β1, pulmonary microvascular endothelial cells (PMVECs), vascular endothelial growth factor (VEGF)