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Abstract: TH-PO214

Diabetes Promotes Nitric Oxide Synthase Remodeling in Glomerular Podocytes

Session Information

Category: Diabetic Kidney Disease

  • 601 Diabetic Kidney Disease: Basic

Authors

  • Stefanenko, Mariia, Medical University of South Carolina, Charleston, South Carolina, United States
  • Semenikhina, Marharyta, Medical University of South Carolina, Charleston, South Carolina, United States
  • Fedoriuk, Mykhailo, Medical University of South Carolina, Charleston, South Carolina, United States
  • Lipschutz, Joshua H., Medical University of South Carolina, Charleston, South Carolina, United States
  • Staruschenko, Alexander, University of South Florida, Tampa, Florida, United States
  • Palygin, Oleg, Medical University of South Carolina, Charleston, South Carolina, United States
Background

The release of nitric oxide (NO) by glomerular cells, together with the renin-angiotensin system (RAS), regulate glomerular filtration. Several reports indicate that NO levels in glomeruli are decreased during renal pathology development while restoring NO levels can benefit glomerular function. However, expression of NOS subunits in podocytes, especially under diseased conditions, was not established.

Methods

To detect NO production and NOS distribution in control and diabetes, we used confocal imaging of podocytes loaded with DAF-FM fluorescent marker. Freshly isolated glomeruli from the Type 2 Diabetic Nephropathy (T2DN) and control Wistar rats, and conditionally immortalized human podocyte cell line exposed to high glucose conditions (12 hrs) were used in the studies. NO production was detected in response to Ang II stimulation, and NOS distribution was determined using NOS1 and NOS2 commercially available inhibitors (Nω-Propyl-L-arginine hydrochloride and L-NIL, respectively).

Results

Under normal conditions, in response to Ang II application, rapid NO production was observed in cultured and Wistar rats isolated glomeruli podocytes. NO release was blocked by preincubation with corresponding NOS inhibitors. Our data indicate that NOS1 is predominant signaling in healthy podocytes (69±5% of total NO response). The rest of the RAS-mediated NO production was attributed to NOS2 (39±5%). Under diabetic conditions, NO release in response to Ang II has slightly decreased with the maximal amplitude of 78±10% of control. Moreover, high glucose drastically changes NOS distribution in cultured podocytes, where NOS2 signaling becomes predominant (89±7 % of total NO response), and NOS1 becomes less significant.

Conclusion

The changes in the distribution of NO sources due to shifts in NOS subunit expression activity may be linked to an increase in oxidative and nitrosative stress. Here we demonstrated that under the condition of diabetes NOS2 activity becomes predominant and may be directly related to the rapid development of the pathological processes in podocytes. Further understanding this fundamental pathway in the glomerulus is essential for efficient treatment and prevention of the development of diabetic kidney disease.

Funding

  • NIDDK Support