Activation of Slit2-Robo1 signaling promotes liver fibrosis

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• 作者：Jianlan Chang² ; ⁵ ; ^&dagger ; ; Tian Lan¹ ; ^&dagger ; ; Changzheng Li¹ ; Xiaoqian Ji¹ ; Lingyun Zheng¹ ; Hongju Gou² ; Yitao Ou¹ ; Teng Wu¹ ; Cuiling Qi¹ ; Qianqian Zhang¹ ; Jiangchao Li¹ ; Quliang Gu¹ ; Dingwen Wen¹ ; Liu Cao⁴ ; Liang Qiao³ ; ^{liang.qiao@sydney.edu.au" class="auth_mail" title="E-mail the corresponding author} ; Yanqing Ding² ; ^{dyq@fimmu.com" class="auth_mail" title="E-mail the corresponding author} ; Lijing Wang¹ ; ^{wanglijing62@163.com" class="auth_mail" title="E-mail the corresponding author}
• 关键词：α-SMA ; α-smooth muscle actin ; CCl4 ; carbon tetrachloride ; ECM ; extracellular matrix ; HSCs ; hepatic stellate cells ; Robo1/2+/&minus ; mice ; Robo1+/&minus ; Robo2+/&minus ; double heterozygotes mice ; Slit2-Tg mice ; Slit2-transgenic mice ; TGF-β1 ; transforming growth factor-β
• 刊名：Journal of Hepatology
• 出版年：2015
• 出版时间：December 2015
• 年：2015
• 卷：63
• 期：6
• 页码：1413-1420
• 全文大小：3675 K

文摘

The secretory protein Slit2 and its receptor Robo1 are believed to regulate cell growth and migration. Here, we aimed to determine whether Slit2-Robo1 signaling mediates the pathogenesis of liver fibrosis.

Methods

Serum levels of Slit2 in patients with liver fibrosis were determined by ELISA. Liver fibrosis was induced in wild-type (WT), Slit2 transgenic (Slit2-Tg) and Robo1^+/−Robo2^+/− double heterozygotes (Robo1/2^+/−) mice by carbon tetrachloride (CCl₄). The functional contributions of Slit2-Robo1 signaling in liver fibrosis and activation of hepatic stellate cells (HSCs) were investigated using primary mouse HSCs and human HSC cell line LX-2.

Results

Significantly increased serum Slit2 levels and hepatic expression of Slit2 and Robo1 were observed in patients with liver fibrosis. Compared to WT mice, Slit2-Tg mice were much more vulnerable to CCl₄-induced liver injury and more readily develop liver fibrosis. Development of hepatic fibrosis in Slit2-Tg mice was associated with a stronger hepatic expression of collagen I and α-smooth muscle actin (α-SMA). However, liver injury and hepatic expression of collagen I and α-SMA were attenuated in CCl₄-treated Robo1/2^+/− mice in response to CCl₄ exposure. In vitro, Robo1 neutralizing antibody R5 and Robo1 siRNA downregulated phosphorylation of Smad2, Smad3, PI3K, and AKT in HSCs independent of TGF-β1. R5 and Robo1 siRNA also inhibited the expression of α-SMA by HSCs. Finally, the protective effect of R5 on the CCl₄-induced liver injury and fibrosis was further verified in mice.

Conclusions

Slit2-Robo1 signaling promotes liver injury and fibrosis through activation of HSCs.