Apoc1 Knockdown Alleviates High Glucose-induced Oxidative Stress and Apoptosis of Renal Tubular Cells by Binding to Clusterin.

Abstract

Diabetic nephropathy (DN) is a serious diabetic complication. Renal tubular damage is an important aspect of DN. Increased apolipoprotein C1 (Apoc1) has been confirmed in serum of patients with DN. The exact mechanism of Apoc1 in DN is unclear as yet. We aimed to elaborate the molecular mechanism underlying high glucose (HG)-induced renal tubular epithelial damage. In this content, a DN mouse model was established to assess renal damage. Apoc1 and Clusterin expression in renal tissue was detected using immunoblotting and immunofluorescence staining. In vitro, human kidney proximal tubular epithelial cells (HK-2 cells) were exposed to HG to simulate the DN model. After Apoc1 and/or Clusterin knockdown, HK-2 cell viability under HG conditions was detected using CCK-8 assay. DCFH-DA staining was used to examine the production of intracellular reactive oxygen species (ROS). MDA and SOD levels were tested by kits. Moreover, cell apoptosis was measured using TUNEL staining. Immunoblotting was employed to evaluate the expression of proteins. Additionally, the binding between Apoc1 and Clusterin was analyzed using co-immunoprecipitation experiments. Our data revealed that Apoc1 expression was upregulated while Clusterin expression was downregulated in renal tissue of DN mice and HG-treated HK-2 cells. Apoc1 knockdown alleviated oxidative stress and apoptosis in HG-treated HK-2 cells. Importantly, Apoc1 could bind to Clusterin and regulate Clusterin expression in HK-2 cells. Finally, Clusterin silencing blocked the influences of Apoc1 knockdown on the oxidative stress and apoptosis in HK-2 cells under HG conditions. Collectively, Apoc1 knockdown exerts potential anti-DN effects by binding to Clusterin to alleviate HG-induced renal tubular damage, suggesting that Apoc1/Clusterin can be used as a valuable therapeutic target for DN.