Knockdown of lncRNA XIST inhibited apoptosis and inflammation in renal fibrosis via microRNA-19b-mediated downregulation of SOX6.

Background: Kidney damage often develops into renal fibrosis. Apoptosis and inflammatory response are the main factors driving the process of renal fibrosis. Here we showed that lncRNA XIST/ miR-19b / SOX6 signal axis regulated apoptosis and inflammation of renal fibrosis.

Methods: HK-2 cells were treated with TGF-β1 to construct cell fibrosis model, and UUO surgery was performed to construct mouse renal fibrosis model. The expression of XIST, miR-19b and SOX6 were examined by qPCR. And levels of fibrosis-related proteins were detected by western blotting. Levels of IL-1β and TNF-α were assessed by qPCR and ELISA, respectively. Renal pathology and fibrosis were evaluated by HE and Masson staining. Flow cytometry and TUNEL staining were employed to evaluate cell apoptosis in cell fibrosis model and mouse renal fibrosis model, respectively. Besides, dual luciferase reporter assay was employed to verify whether XIST had a binding site to miR-19b, and whether miR-19b had a binding site to SOX6.

Results: Here we showed that XIST and SOX6 were upregulated in both HK-2 cells treatment of TGF-β1 and kidneys of UUO mice, while miR-19b was downregulated. Dual luciferase reporter assay displayed that XIST directly bound to miR-19b, and SOX6 was the target of miR-19b. Knockdown of XIST inhibited apoptosis, inflammation and fibrosis in HK-2 cells treatment of TGF-β1 via miR-19b-mediated downregulation of SOX6, while inhibition of miR-19b reversed the effect. Similarly, knockdown of XIST in vivo inhibited apoptosis, inflammation and fibrosis in kidneys of UUO mice via miR-19b-mediated downregulation of SOX6.

Discussion: These results provided evidence that knockdown of XIST inhibited apoptosis and inflammation of renal fibrosis via miR-19b-mediated downregulation of SOX6.