S1PR2/Wnt3a/RhoA/ROCK1/ß-catenin signaling pathway promotes diabetic nephropathy by inducting endothelial mesenchymal transition and impairing endothelial barrier function.

AIMS: Hyperglycemia and hyperlipidemia are key factors in the pathogenesis of diabetic nephropathy (DN), and renal fibrosis is the most common pathway leading to the disease. Endothelial mesenchymal transition (EndMT) is a crucial mechanism for the production of myofibroblasts, and impaired endothelial barrier function is one of the mechanisms for the generation of microalbuminuria in DN. However, the specific mechanisms behind these are not yet clear. MAIN METHODS: Protein expression was detected by immunofluorescence, immunohistochemistry and Western blot. Knocking down or pharmacological inhibition of S1PR2 were used to inhibit Wnt3a, RhoA, ROCK1, ß-catenin, and Snail signaling. Changes in cell function were analyzed by CCK-8 method, cell scratching assay, FITC-dextran permeability assay, and Evans blue staining. KEY FINDINGS: Consistent with increased gene expression of S1PR2 in DN patients and mice with kidney fibrosis disease, S1PR2 expression was significantly increased in glomerular endothelial cells of DN mice and HUVEC cells treated with glucolipids. Knocking down or pharmacological inhibition of S1PR2 significantly decreased the expression of Wnt3a, RhoA, ROCK1, and ß-catenin in endothelial cells. Furthermore, inhibition of S1PR2 in vivo reversed EndMT and endothelial barrier dysfunction in glomerular endothelial cells. Inhibition of S1PR2 and ROCK1 in vitro also reversed EndMT and endothelial barrier dysfunction in endothelial cells. SIGNIFICANCE: Our results suggest that the S1PR2/Wnt3a/RhoA/ROCK1/ß-catenin signaling pathway is involved in the pathogenesis of DN by inducing EndMT and endothelial barrier dysfunction.

S1PR2/RhoA/ROCK1 pathway promotes inflammatory bowel disease by inducing intestinal vascular endothelial barrier damage and M1 macrophage polarization.

Vascular and immune dysfunctions are thought to be related to the pathogenesis of inflammatory bowel disease (IBD), but behind this, the exact mechanism of mucosal vascular endothelial barrier dysfunction and macrophage phenotypic transition is not fully understood. Here, we explored the mechanistic role of sphingosine 1-phosphate receptor 2 (S1PR2) and its downstream G protein RhoA/Rho kinase 1 (ROCK1) signaling pathway in the intestinal endothelial barrier damage and M1 macrophage polarization in IBD. We found that the expression of S1PR2 in intestinal mucosal vascular endothelial cells and macrophages of IBD patients and DSS-induced colitis mice as well as vascular endothelial cells and macrophages treated with LPS in vitro was significantly increased. Knocking down or pharmacologically inhibiting S1PR2 significantly downregulated the expression of RhoA and ROCK1 in vascular endothelial cells and macrophages. Furthermore, inhibition of S1PR2 and ROCK1 reversed the impaired vascular barrier function and M1 macrophage polarization in vivo and in vitro, while reducing ER stress in vascular endothelial cells and glycolysis in macrophages. In addition, inhibition of ER stress or glycolysis reversed LPS-induced impairment of vascular endothelial cell barrier function and M1 macrophage polarization. Collectively, our results indicate that the S1PR2/RhoA/ROCK1 signaling pathway may participate in the pathogenesis of IBD by regulating vascular endothelial barrier function and M1 macrophage polarization.