Abstract: TH-PO700

Modulation of Epigenetics Led to a Decrease in Proteinuria in a Mouse Model of Diabetic Podocytopathy

Session Information

Category: Diabetes

  • 501 Diabetes Mellitus and Obesity: Basic - Experimental

Authors

  • Vashistha, Himanshu, Ochsner Health System, New Orleans, Louisiana, United States
  • Mishra, Abheepsa, Feinstein Institute of Medical Research, Northwell Health, MANHASSET, New York, United States
  • Malhotra, Ashwani, Feinstein Inst.Med research and NSLIJ, Manhasset, New York, United States
  • Meggs, Leonard G., Ochsnher Health Foundation, New Orleans, Louisiana, United States
  • Singhal, Pravin C., North Shore LIJ Health System, Great Neck, New York, United States
Background

Modulation of renin angiotensin system has been reported to slow down the progression of diabetic podocytopathy by alterations of hemodynamic factors. Recent reports suggest that epigenetic factors also contribute to the development and progression of diabetic podocytopathy. We evaluated blockade effect of Angiotensin II (Ang II) on reversal of epigenetic alterations in diabetic podocytopathy. We hypothesize that demethylation by a low-dose hydralazine (HYDZ, non-hypertensive dose) would further augment the effect of Ang II blockade on reversal of epigenetic factors and decrease proteinuria in diabetic mice

Methods

Protein blots of renal tissues/cortical sections of 2, 4, and 6 months old control and Akita mice (diabetic, n=3) were probed for methylation at histone (H)3 lysine (K)4 residues, acetylation at H3 lysine (K)9 residues, SNAIL, vitamin D receptor (VDR), and nephrin. In vitro studies, protein blots of control ( glucose, 5 mM) and high glucose (30 mM, HG)-treated human podocytes (HPs) were probed for SNAIL, VDR, nephrin, H3K4me3, H3K9ac and actin. Podocyte VDR and nephrin gene methylation status (Bisulphite pyrosequencing) and SNAIL binding to VDR and nephrin promoters (ChIP assay) were determined. Control and Akita mice (n=4) were treated with losartan (an Ang II receptor blocker, 10 mg/Kg/day) with/without HYDZ (10 mg/kg/day, 4 weeks) followed by evaluation of proteinuria and renal epigenetic alterations.

Results

Protein blots of renal tissues/cortical sections of Akita mice and HG/HPs displayed enhanced expression of SNAIL and H3K4me3 but down regulation of VDR, nephrin and H3K9ac. Losartan not only decreased proteinuria but also partially reversed epigenetic alterations and associated SNAIL, VDR and nephrin expressions; HYDZ alone has similar effects on proteinuria and epigenetic markers and further augmented these effects when combined with losartan. Both nephrin and VDR displayed more than 70% cytosine methylation (CpG islands). HG/HP displayed deacetylation of nephrin and degradation via ubiquitation. ChIP assays revealed binding of SNAIL at VDR and nephrin promoters.

Conclusion

Reversal of epigenetic alterations in renal tissues contributed to decrease in proteinuria in diabetic mice.

Funding

  • NIDDK Support