Abstract: SA-PO125

Role of Wnt-β Catenin Pathway in Mediating Salutary Effects of Paricalcitol in Experimental Diabetic Nephropathy

Session Information

Category: Diabetes

  • 503 Diabetes Mellitus and Obesity: Translational

Authors

  • Prabhakar, Sharma S., Texas Tech University Health Sciences Center, Lubbock, Texas, United States
  • Bose, Madhura, Texas Tech University Health Sciences Center, Lubbock, Texas, United States
Background


Diabetic nephropathy (DN) remains the most frequent cause of end stage renal disease but its pathogenesis remains unclear and consequently the treatment is not optimal. Many investigations including ours have shown renoprotective effects of paricalcitol (PAR) in DN. The aim of the current studies is to examine the role of Wnt- β catenin signaling in the beneficial effects of PAR in DN.

Methods

Obese ZSF rats, an established model of DN (type 2 diabetes), were treated with PAR (0.2 µg sc. twice a week) for 10 weeks from 21 weeks of age while control rats received none. Urine and blood samples were collected at the start and end of study. At 31 weeks rats were sacrificed, kidneys harvested and homogenates of one kidney in each rat were used to study expression of Wnt proteins and other pathogenic mediators by immunoblotting while the other kidney was used for RNA isolation and Next Gen Sequencing (NGS) analysis. Kidney RNA seq data from ZSF obese and PAR treated rats were compared. Genes that were significantly altered based on 95% confidence and Log 2 fold change were filtered and mapped to canonical pathways in the IPA Knowledge Base. The dataset was filtered and a student t test was used to identify the genes most significantly altered following PAR treatment.

Results

PAR decreased proteinuria (970 mg/dl vs.1750 mg/dl in control) and slowed the decline of GFR (Ccr 3.6 L/Kg/BW vs.2.7 L/Kg/BW in control) in obese ZSF rats. NGS analysis of kidneys revealed that Wnt-β catenin signaling (which was differentially expressed compared to non-diabetic lean ZSF rats, per previous studies) is significantly altered in treated rats suggesting that changes in these pathways could account for the salutary effects of PAR. Western blot data confirmed that PAR inhibited the expression of many proteins in the Wnt signaling pathways specifically Wnt-3, Wnt-11 and c-myc . Other significant changes included Nitric Oxide, and OX-40 pathways in NGS and upregulation of phospho-eNOS, and inhibition of CTGF and NFkB protein expression.

Conclusion

We conclude that Wnt- β catenin is one of the important canonical pathways differentially modified by PAR and inhibition of Wnt proteins, along with changes in eNOS and CTGF may significantly contribute to renoprotective effects of PAR. These observations could potentially aid the development of novel therapies for DN.

Funding

  • Private Foundation Support