Abstract: SA-PO384

Angiotensin II Induces Cholesterol Accumulation and Injury in Podocytes

Session Information

Category: Chronic Kidney Disease (Non-Dialysis)

  • 301 CKD: Risk Factors for Incidence and Progression

Author

  • Yang, Yingjie, Renmin Hospital of Wuhan University, Wuhan, China
Background

Angiotensin‖ (Ang‖) is a risk factor for the initiation and progression of chronic kidney disease (CKD), elevated Ang‖ levels can lead to podocyte injury. Cholesterol is major component of lipid droplet (LD), cholesterol homeostasis exerts an important role in podocyte physiology. However, there are no studies on the role of Ang‖ in cholesterol metabolism or on the podocyte injury caused by cholesterol metabolism disorder.

Methods

In vivo, Oil red O and Nile red staining were evaluated LD deposition in glomeruli of Ang‖-infused rats. The expression of LD marker ADRP and WT-1 by double immunolabeling was evaluated LD distribution in podocytes. In vitro, human podocytes were exposed to Ang‖ (10-7M) for 24 h. LD was observed by Oil red O and Nile red staining. The expression of ADRP was determined by immunofluorescence and Western blot. Cholesterol content was tested by cholesterol quantitation kit. The expression of cholesterol metabolism-related molecules was determined by Real-time PCR and Western blot. Cholesterol efflux inducer methyl-β-cyclodextrin (CD) and cholesterol synthesis enzyme antagonist simvastatin were respectively pretreated to podocytes. Podocyte apoptosis was assessed by flow cytometry.

Results

In vivo, Oil red O and Nile red staining indicated that LD accumulated in glomeruli of Ang‖-infused rats. Double immunolabeling of ADRP and WT-1 showed that LD deposited in podocytes. In vitro, LD was detected in podocyte exposed to Ang‖ but little in controls. The expression of ADRP was upregulated by Ang‖. Cholesterol content was also increased, which was accompanied by decreased expression of cholesterol efflux-related molecule ABCA1 and increased expression of the cholesterol uptake-related molecule LDLR and cholesterol synthesis-related molecules SREBP-1, SREBP-2 and HMGCR. Treatment of Ang‖-stimulated podocytes with CD showed that CD could decrease Ang‖-induced cholesterol accumulation and reduce Ang‖-induced podocyte apoptosis. Treatment of Ang‖-treated podocytes with simvastatin indicated that simvastatin did not improve Ang‖-induced cholesterol accumulation and podocyte apoptosis.

Conclusion

The present study suggests that Ang‖ induces podocyte cholesterol accumulation by regulating the expression of cholesterol metabolism related-molecules. Excess cholesterol induces podocyte injury.