Gremlin1通过VEGFR2途径促血管生成在肝纤维化中的作用

Role of gremlin1 promoting angiogenesis through VEGFR2 pathway in liver fibrosis

目的 通过四氯化碳(CCL_(4))诱导小鼠肝纤维化动物模型以及体外培养肝窦内皮细胞(HSEC)试验,研究Gremlin1通过激活VEGFR2途径促血管生成在肝纤维化发生机制中的作用。方法 建立CCL_(4)小鼠肝纤维化动物模型,利用天狼星红染色法观察模型小鼠肝组织纤维化程度,利用免疫组织化学法和Western blot方法检测模型小鼠纤维化肝组织中Gremlin1、VEGFR2、CD31及vWF的表达情况。培养HSEC,设对照组、Gremlin1(200μg/L)组、Gremlin1(200μg/L)+SU1498(700μg/L)组,培养24 h,用Western-blot检测vWF、CD31的蛋白质表达。结果 模型小鼠纤维化肝组织中Gremlin1、VEGFR2、CD31及vWF的表达水平明显高于正常对照组(P<0.05),而且Gremlin1在小鼠纤维化肝组织中的表达水平与VEGFR2、CD31及vWF的表达水平呈正相关(P<0.01)。Gremlin1可以诱导肝窦内皮细胞CD31、vWF蛋白表达增加(P<0.05),VEGFR2阻断剂SU1498可以抑制Gremlin1对CD31、vWF表达的上调作用(P<0.05)。结论 Gremlin1可能通过激活VEGFR2信号通路促血管生成来参与肝纤维化的整个发生和发展过程。

Objective The role of gremlin1 in promoting angiogenesis through VEGFR2 pathway in the pathogenesis of liver fibrosis was studied in carbon tetrachloride(CCl_(4))-induced mouse liver fibrosis animal model and cultured hepatic sinusoidal endothelial cell line(HSEC) in vitro.Methods The animal model of liver fibrosis in CCl_(4)-treated mice was established.The degree of liver fibrosis in the model mice was observed by Sirius red staining.The expressions of Gremlin1,VEGFR2,CD31 and vWF in the fibrotic liver of the model mice were detected by immunohistochemistry and Western blot.HSEC was cultured in control group,gremlin1(200μg/L) group and gremlin1(200μg/L) + SU1498(700 μg/L) group for 24 hours.The protein expressions of vWF and CD31 were detected by Western blot.Results The expression levels of Gremlin1,VEGFR2,CD31 and vWF in fibrotic liver tissue of model mice were significantly higher than those in normal control group(P<0.05);Moreover,the expression level of gremlin1 in mouse fibrotic liver tissue was positively correlated with the expression levels of VEGFR2,CD31 and vWF(P<0.01).Gremlin1 could induce the increase of CD31 and vWF protein expression in hepatic sinusoidal endothelial cells(P<0.05),VEGFR2 blocker SU1498 could inhibit the up-regulation of CD31 and vWF expression by gremlin1(P<0.05).Conclusion Gremlin1 may participate in the occurrence and development of liver fibrosis by activating VEGFR2 signaling pathway and promoting angiogenesis.