Abstract: TH-OR117

Aging Phenotype(s) in Kidneys of Diabetic Mice Are p66ShcA Dependent

Session Information

  • Scarred for Life?
    November 02, 2017 | Location: Room 394, Morial Convention Center
    Abstract Time: 06:18 PM - 06:30 PM

Category: Chronic Kidney Disease (Non-Dialysis)

  • 308 CKD: Mechanisms of Tubulointerstitial Fibrosis

Authors

  • Vashistha, Himanshu, Ochsner Health System, New Orleans, Louisiana, United States
  • Bradley, Allyson E., Ochsner Health System, New Orleans, Louisiana, United States
  • Leblanc, Bronwyn, Ochsner Health System, New Orleans, Louisiana, United States
  • Abbruscato, Frank C, Ochsner Health System, New Orleans, Louisiana, United States
  • Malhotra, Ashwani, Feinstein Inst.Med research and NSLIJ, Manhasset, New York, United States
  • Singhal, Pravin C., Feinstein Inst.Med research and NSLIJ, Manhasset, New York, United States
  • Meggs, Leonard G., Ochsner Health System, New Orleans, Louisiana, United States
Background

Hyperglycemia constitutively activates the p66ShcA protein, which controls cellular responses to oxidative stress, aging and apoptosis . Here, we test the hypothesis aging phenotype(s) in kidneys of diabetic mice, that are commonly associated with the broad category of chronic kidney disease (glomerulosclerosis, interstitial fibrosis, tubular atrophy), are linked to the p66ShcA locus.

Methods

Stem cell antigen-1+ (Sca-1+) mesenchymal stem cells (MSCs) were isolated from kidneys of WT and p66 KO mouse, and plated in media containing normal or high glucose. Parameters evaluated were ROS metabolism, apoptosis, cellular and molecular markers of senescence and DNA microarray gene profiles. p66 KO diabetic mice, were generated by crossing Akita (Ins2+) with p66 KO mouse. Kidneys were examined at 12 mo of age by light microscopy and deconvolution microscopy.

Results

WT-MSCs exhibit an exponential increase in ROS metabolism, upregulation of senescence associated proteins (p21; p16INK4a; p53) and enter apoptotic or senescent phenotypes. DNA microarray detected downregulation of Wnt regulatory genes, implicated in self renewal and differentiation. By contrast, p66KO-MSCs are resistant to HG-stress signals, apoptosis/cell senescence and express increase levels of intracellular b-catenin, mimicking canonical Wnt signaling.
Small clusters of Sca-1+MSCs in kidneys of p66 KO Akita were captured by deconvolution microscopy scattered in the interstitium adjacent to tubules, but were only rarely seen in kidneys of WT and Akita. Furthermore, the senescent biomarker p16INK4a was upregulated in proximal tubular epithelial cells of Akita, whereas expression levels did not differ between p66 KO-Akita and WT (non-diabetic ); indicative p66ShcA participates in activation of p16INK4a in diabetic kidneys.
Histologic markers of aging were prominent in Akita kidneys, whereas these aging phenotypes were barely detectable in kidneys of p66 KO-Akita. Taken together, p66 ShcA is necessary and sufficient for the expression of aging phenotypes in kidneys of diabetic mice.

Conclusion

Our results establish a genetic link between diabetes, constitutive p66ShcA expression and accelerated aging phenotype(s) in the kidney, that may serve as precursors to diabetic nephropathy.

Funding

  • Private Foundation Support