Slit2/Robo1 Mitigates DSS-induced Ulcerative Colitis by Activating Autophagy in Intestinal Stem Cell
Jingzhou Xie, Li Li, Shuhua Deng, Jiayuan Chen, Quliang Gu, Huanhou Su, Lijing Wen, Sheng Wang, Caixia Lin, Cuiling Qi, Qianqian Zhang, Jiangchao Li, Xiaodong He, Weidong Li, Lijing Wang, Lingyun Zheng
Abstract
Ulcerative colitis (UC) is a recurrent intestinal inflammatory disease. Slit2, a secreted protein, interacts with its receptor Robo1 to regulate the differentiation of intestinal stem cells and participate in inflammation and tumor development. However, whether Slit2/Robo1involved in the pathogenesis of UC is not known. We investigated Slit2/Robo1-mediated UC using a dextran sodium sulfate (DSS)-induced model. Eight-week-old male Slit2-Tg (Slit2 transgene) mice, Robo1/2 +/- (Robo1 +/-Robo2 +/-) mice, and their WT littermates were allocated into two groups: (I) control group (n=10), of mice fed a normal diet and tap water and (II) DSS group (n=10), of mice fed a normal diet and drinking water with 2% DSS for 7 days. Colon tissues were collected and analyzed by qPCR, immunohistochemistry, western blot, and immunofluorescence. Slit2-Tg DSS mice showed less body weight loss, less blood in the stool, and less viscous stool compared to those of WT Slit DSS mice. Robo1/2 +/-DSS mice displayed a heavier degree of blood in the stool and a more apparent viscosity of the stool compared to those of WT Robo1/2 DSS mice. Slit2 overexpression maintained Lgr5 + stem cell proliferation in the crypt after DSS treatment, significantly increased the LC3II/I ratio, and slightly stimulated p62 expression in the crypt compared to those of DSS-induced WT Slit mice. Robo1/2 partial knockout reduced the number of Lgr5 + stem cells, decreased the LC3II/I ratio, and markedly increased p62 expression in the crypt compare to those of DSS-treated WT Robo1/2 mice. Our findings suggest that Slit2/Robo1 mediates DSS-induced UC probably by activating the autophagy of Lgr5 + stem cells.