Dedicator of cytokinesis protein 2 activates the epithelial–mesenchymal transition in renal fibrosis through the Rac1/PI3K/AKT pathway

Renal fibrosis is the most important feature of the progression of chronic kidney disease (CKD), and epithelial–mesenchymal transition (EMT) plays an important role in renal fibrosis. Dedicator of cytokinesis protein 2 (Dock2) is involved in the immune system and the development of a variety of fibrotic diseases. However, its specific role in renal fibrosis remains unclear. Therefore, in this study, we investigated the role and mechanism of Dock2 in renal fibrosis. We constructed an in vivo mouse model of unilateral ureteral obstruction (UUO) and an in vitro model of recombinant human transforming growth factor-β1 (TGF-β1)-induced HK-2 cells. The function and regulatory mechanism of Dock2 were studied via Western blotting, qRT-PCR, immunohistochemistry and immunofluorescence. First, Dock2 was more highly expressed in the kidneys of UUO mice than in those of sham-operated mice. A reduction in Dock2 can improve pathological changes in the kidney tissue of UUO mice, reduce the deposition of the extracellular matrix (ECM), and alleviate EMT. Silencing Dock2 reduced the activation of both the Rac1 pathway and the PI3K/AKT pathway. TGF-β1 promoted Dock2 expression in HK-2 cells in vitro. A decrease in Dock2 can inhibit the expression of Fibronectin, Collagen I, α-SMA and Vimentin and increase the level of E-cadherin. Treatment of HK-2 cells with the Rac1 activator 8-CPT or the PI3K/AKT pathway activator YS-49 inhibited the above changes induced by siDock2, indicating that Dock2 activates EMT in renal fibrosis through the Rac1/PI3K/AKT pathway. Our data suggest that Dock2 may be a potential target for renal fibrosis treatment.