Potential Repressive Impact of microRNA-20a on Renal Tubular Damage in Diabetic Kidney Disease by Targeting C-X-C Motif Chemokine Ligand 6

Abstract

C-X-C Motif Chemokine Ligand 6 (CXCL6) is an important chemokine. We attempt in this investigation to explore its role and possible mechanism in diabetic kidney disease (DKD). By intergrating GEO data, CXCL6 expression in DKD patients and normal controls was exhibited. miRWalk website and luciferase reporter assay were used to predict and verify the upstream miRNA of CXCL6. CCK-8 assay and flow cytometry were performed to detect proliferation and apoptosis capacities. The levels of inflammatory key factors (TNF-α, IL-6 and IL-8) were measured using ELISA analysis. Expression of CXCL6, miR-20a, and JAK/STAT3 pathway-related markers were detected by qRT-PCR or western blot assays. CXCL6 was increased in DKD. miR-20a was identified as an upstream regulatory miRNA of CXCL6, and its expression was decreased in DKD and HG-treated HK-2cells. miR-20a overexpression facilitated the proliferation of HG-treated HK-2cells, whereas miR-20a depletion exhibited the opposite phenomenon. The levels of TNF-α, IL-6 and IL-8 were increased by HG treatment in HK-2cells. CXCL6 antagonized the promoting impacts of miR-20a mimics on HG-exposed HK-2cell proliferation. The suppressive effect of miR-20a overexpression on apoptosis and inflammatory response of HG-induced HK-2cell was rescued by CXCL6 enhancement. The protein expression of p-JAK and p-STAT3 were reduced by miR-20a mimic while facilitated by CXCL6 overexpression in HG-stimulated HK-2cells. These consequences hinted that miR-20a might exert a repressive impact on DKD, possibly through targeting CXCL6 and mediating JAK/STAT3 pathway, which offer new targets for DKD treatment.