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Abstract: FR-PO399

Sirt6 Protects Podocytes from High Glucose-Induced Mitochondrial Dysfunction and Apoptosis Through AMPK Activation

Session Information

Category: Diabetic Kidney Disease

  • 601 Diabetic Kidney Disease: Basic

Authors

  • Ding, Guohua, Renmin Hospital of Wuhan University, Wuhan, China
  • Fan, Yanqin, Renmin Hospital of Wuhan University, Wuhan, China

Group or Team Name

  • Division of Nephrology, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
Background

Previous studies have shown that mitochondrial dysfunction plays an important role in podocyte injury. Sirt6 has been revealed with essential roles in the regulation of mitochondrial function. However, the pathological features and molecular mechanism of mitochondrial damage in podocytes under high glucose (HG) condition remains unknown. The present study aims to observe the changes of podocyte mitochondria under HG and to evaluate whether Sirt6 contributes to HG-induced podocytes apoptosis through modulating mitochondrial function.

Methods

In vivo study, transmission electron microscope (TEM) was used to identify ultrastructure changes of podocyte mitochondria in diabetic mice. Co-localization expression of Sirt6 and WT-1 was evaluated in glomeruli by double immunolabeling. Western blot was performed to assess Sirt6 and p-AMPK expression in glomeruli. In vitro study, conditionally immortalized human podocytes were exposed to HG (30mM) for 24 h. Mitochondria ultrastructure was observed by TEM. Mitochondrial number and ROS production were respectively evaluated by Mito Green and MitoSox Red staining. Mitochondrial membrane potential was determined by JC-1 staining. Flow cytometry was used to assess podocyte apoptosis. Western blot was performed to evaluate Sirt6 and p-AMPK expression.pcDNA3.1 SIRT6 was transfect to podocytes to evaluate the effect of Sirt6 over-expression on mitochondrial function and podocyte apoptosis under HG stimulation.

Results

Ultrastructural changes of podocytes in diabetic mice included mitochondria swelling, vacuoles formation, and mitochondrial cristae fracture. Double immunolabeling of Sirt6 and WT-1in glomeruli was obviously decreased in diabetic animals. In addition, p-AMPK expression was reduced in diabetic mice compared with controls. In cultured podocytes, TEM studies showed mitochondria swelling and cristae fracture under HG treatment. HG induced decrease in mitochondrial number and increase in mitochondrial ROS production. Furthermore, HG induced decreased mitochondrial membrane potential. All these changes were significantly alleviated by pcDNA3.1 SIRT6 transfection. Sirt6 overexpression also stimulated p-AMPK expression and alleviated HG-induced podocyte apoptosis.

Conclusion

These results indicate that Sirt6 could protect podocytes from high glucose-induced mitochondrial damage and apoptosis via AMPK activation.

Funding

  • Government Support - Non-U.S.