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Kidney Week

Abstract: FR-PO415

ARF6: A Possible Molecular Target for Diabetic Kidney Disease?

Session Information

Category: Diabetic Kidney Disease

  • 601 Diabetic Kidney Disease: Basic

Authors

  • Lin, Jamie, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States
  • Green, Nathanael, Baylor College of Medicine, Houston, Texas, United States
  • Galvan, Daniel L., The University of Texas MD Anderson Cancer Center, Houston, Texas, United States
  • Long, Jianyin, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States
  • Chang, Benny B., Baylor College of Medicine, Houston, Texas, United States
  • Danesh, Farhad R., The University of Texas MD Anderson Cancer Center, Houston, Texas, United States
Background

Podocytes are key target cells that determine the progression of diabetic kidney disease (DKD), the leading cause of renal failure in the U.S. It is now clear that small GTPase proteins have quintessential roles that govern podocyte health – too much or too little GTPase activity can make the podocyte more susceptible to injury. We recently discovered that ADP-ribosylation factor 6 (ARF6), a Ras-family small GTPase protein, is present in human podocytes and involved in podocyte response to in vivo glomerular injury models; however, its role in DKD is unknown. Since ARF6 is involved in diverse cellular events (e.g. actin rearrangement or endocytic trafficking), we postulate that alterations in ARF6 activity might have injury-specific effects on kidney function and that glucose-induced activation of ARF6 in podocytes contributes to the progression of DKD.

Methods

We used an integrated genetic and pharmacologic approach by taking advantage of the CRISPR-Cas9 system to generate an ARF6-gene deleted mouse podocyte line as well as a selective ARF6 inhibitor, NAV2729 (R&D Systems). Mouse podocyte cell lines were cultured under normal glucose (NG, 5mM) or high glucose (HG, 25 mM) conditions for 48 hours.

Results

Podocytes cultured under HG conditions expressed significantly higher Arf6 mRNA and protein levels compared to podocytes cultured under NG conditions. Isolated podocytes from diabetic (Leprdb/db) mice had increased ARF6 expression compared to control (Leprdb/+) mice. Furthermore, we generated an ARF6-gene deleted mouse podocyte cell line in which we found that ARF6 knockout podocytes had augmented mitochondrial ROS production. To determine whether ARF6 might serve as a molecular target for pharmacologic inhibition in DKD, diabetic and control mice were treated with an ARF6 inhibitor (NAV2729) or vehicle (DMSO) at a dose of 60 mg/kg starting at 8 weeks of age. NAV2729-treated diabetic mice demonstrated significant improvement in the urine albumin to creatinine ratio (UACR) compared to diabetic mice treated with vehicle suggesting a nephro-protective effect of ARF6 inhibition.

Conclusion

These results suggest that ARF6 is an important protein involved in podocyte health. ARF6 expression is increased under diabetic conditions. Inhibition of ARF6 might prevent podocyte injury and DKD progression.

Funding

  • Private Foundation Support