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Abstract: FR-OR101

Podocyte-Derived Endothelin-1 and Cross-Talk with Endothelial Cells Through EdnrA Is Essential for Glomerular Injury

Session Information

Category: Glomerular Diseases

  • 1403 Podocyte Biology

Authors

  • Daehn, Ilse S., Icahn School of Medicine at Mount Sinai, New York, New York, United States
  • Yu, Liping, Icahn School of Medicine at Mount Sinai, New York, New York, United States
  • Yi, Zhengzi, Icahn School of Medicine at Mount Sinai, New York, New York, United States
  • Zhang, Weijia, Icahn School of Medicine at Mount Sinai, New York, New York, United States
Background

Crosstalk between activated podocytes and glomerular endothelial cells (GECs) has been demonstrated in mouse models of focal segmental glomerulosclerosis (FSGS). We have previously demonstrated that podocytes activation can result in GEC stress and dysfunction and concomitant albuminuria via increased endothelin-1 and endothelin receptor A (Edn1/Ednra) signaling. However, the mechanistic link between podocyte activation and Edn1 production, GEC injury, and reciprocal crosstalk that results in podocyte loss and albuminuria remains unclear.

Methods

Transforming growth factor-β (TGFβ) is a cytokine that is implicated in glomerular diseases and podocyte depletion. We examined the effects of TGFβ on podocyte activation in culture on Edn1 expression on podocytes in culture, as well as in podocytes with inducible TGFβR1 expression; PodTgfbR1, treated with doxycycline (Dox). We performed RNAseq analysis on GECs treated with Edn1 and isolated from Dox treated PodTgfbR1 mice. We generated a mouse model through targeted gene deletion of Edn1 in podocytes using the Cre-loxP system (Npsh2:Cre-ET1fl/fl) and a quadruple transgenic mice line with podocyte specific Edn1 knockout, and inducible, podocytes specific TGFβR1 signaling (Nphs2:Cre-ET1-Nephs1TgfbrI). Mice were treated with adriamycin (i.p.) or with Dox (food) to induce nephropathy.

Results

TGFβ signaling resulted in a significant increase in Edn1 expression and Edn1 release by podocytes in culture, which was prevented by a TGFβR1/Smad inhibitor or by knockout (ko) Smad2 or double ko Smad2/3, suggesting canonical TGFβ signaling dependent pathway is required for Edn1 production. RNAseq from Edn1 treated GECs showed upregulation of cellular responses to stress and endothelial dysfunction. Compared to adriamycin treated control Npsh2:Cre-ET1+l+, adriamycin treated Npsh2:Cre-ET1fl/fl mice had reduced glomerular injury, albuminuria and podocyte depletion. Compared to Nephs1TgfbrI, Nphs2:Cre-ET1-Nephs1TgfbrI mice treated with Dox had no glomerular injury, albuminuria and podocyte depletion was completely prevented, and there was no increase in GEC associated Ednra expression.

Conclusion

Our studies provide evidence for the essential role of podocyte derived Edn1 upon activation and crosstalk with GECs via Ednra that results in GEC injury, podocyte depletion and albuminuria in experimental FSGS.

Funding

  • NIDDK Support