转化生长因子-RhoGTP酶/Rho激酶系统信号通路在低氧诱导大鼠肾小球内皮细胞-间充质细胞转分化中的作用及机制研究

The role and mechanism of transforming growth factor-RhoGTPase/Rho Kinase signaling pathway in hypoxia-induced trans-differentiation of rat glomerular endothelial cells

目的低氧对大鼠肾小球内皮细胞(rat glomerular endothelial cells,rGECs)转化生长因子(transforming growth factor,TGF)-β1的表达和转分化相关蛋白表达的影响及机制研究。方法低氧培养箱培养rGECs,根据低氧培养时间将细胞随机分为5组,检测细胞增殖活性、TGF-β1及转分化相关蛋白表达情况;在低氧培养细胞中在合适的时间分别加入RhoA/ROCK阻滞剂和TGF-β1受体阻滞剂,分别再次测定:①细胞培养液中TGF-β1表达;②转分化相关蛋白表达;③RhoA/ROCK活性变化。结果①随着低氧培养时间的延长,rGECs增殖活性增加,72h活性最大(F=546.63,P<0.001);②与常氧组比较,低氧组的TGF-β1(F=16.320,P<0.001)和α-SMA(F=5.032,P=0.009)表达升高,而CD-31(F=9.882,P<0.001)表达降低;③经RhoA/ROCK阻滞剂和TGF-β1受体阻滞剂阻滞后α-SMA蛋白表达下降(相对表达量由1.423分别下降至0.750、0.434),CD-31蛋白表达升高(相对表达量由0.741分别上升至0.779、0.934)。结论研究发现低氧可致rGECs增殖活性增加,促进rGECs向间质细胞转分化。并通过细胞信号阻滞剂研究发现低氧可能通过TGF-β1-RhoA/ROCK信号通路促进rGECs向间质细胞转分化。

Purpose To investigate the effect and mechanism of hypoxia on the expression of TGF-β1 and the proteins relating to endothelial-to-mesenchymal transition(EndMT)in rat glomerular endothelial cells(rGECs).Methods rGECs were cultured in a hypoxia incubator,and the cells were randomly divided into 5 groups according to hypoxia treatment time.Cell proliferation activity,the expression of TGF-β1 and EndMT related proteins were then measured in the 5 cell groups.RhoA/ROCK blocker and TGF-β1 receptor blocker were added to the hypoxia treated cells at appropriate time,and then the following indicators were assayed:①TGF-β1 in cell culture medium;②TGF-β1 and EndMT related proteins;③change of RhoA/ROCK activity.Results①The proliferative activity of rGECs increased with the prolongation of hypoxia treatment time with the biggest activity after hypoxia treatment for 72 hours(2.040±0.110,F=546.63,P<0.001);②Compared with the normoxic group,the expressions of TGF-β1(F=16.320,P<0.001)and α-SMA(F=5.032,P=0.009)in the hypoxic group increased significantly,while CD-31 protein(F=9.882,P<0.001)decreased significantly.③Under the hypoxic circumstances and treated with RhoA/ROCK blocker and TGF-β1 blocker,α-SMA protein decreased(relative amount from 1.423 to 0.750 and 0.434 respectively)and CD-31 protein increased(relative amount from 0.741 to 0.779 and 0.934 respectively).Conclusion Hypoxia can increase cell proliferation and promote EndMT of rGECs.The use of TGF-β1 and RhoA/ROCK blockers under hypoxic conditions suggest that hypoxia environment promotes EndMT of rGECs via the TGF-β1-RhoA/ROCK signaling pathway.