ASN's Mission

ASN leads the fight to prevent, treat, and cure kidney diseases throughout the world by educating health professionals and scientists, advancing research and innovation, communicating new knowledge, and advocating for the highest quality care for patients.

learn more

Contact ASN

1401 H St, NW, Ste 900, Washington, DC 20005

email@asn-online.org

202-640-4660

The Latest on Twitter

Kidney Week

Abstract: TH-PO1080

The Ephrin Signaling Pathway Is a Novel Target of Wt1-Induced Gene-Regulatory Reprogramming in FSGS Progression

Session Information

Category: Glomerular Diseases

  • 1204 Podocyte Biology

Authors

  • Padvitski, Tsimafei, University of Cologne, Köln, Germany
  • Unnersjö-Jess, David, Royal Institute of Technology, Solna, Sweden
  • Schermer, Bernhard, University of Cologne, Cologne, NW, Germany
  • Benzing, Thomas, University of Cologne, Cologne, NW, Germany
  • Beyer, Andreas, University of Cologne, Köln, Germany
  • Kann, Martin, University of Cologne, Cologne, NW, Germany
Background

While mutations in podocyte transcription factors (TF) can cause FSGS, gene-regulatory processes governed by TFs in glomeruli are unclear. Here, we investigate gene-regulatory reprogramming due to Wt1 depletion in an early and progressed stage of murine FSGS using an epigenomic and transcriptomic approach.

Methods

The Wt1 heterozygous null mouse model (Wt1-hetdel) and littermate controls were used for RNAseq of glomeruli in early proteinuric and progressed sclerotic stages of disease, as well as ChIPseq for Wt1 at an early disease stage. Proteomics and STED microscopy were used to investigate glomerular protein abundance and ultrastructure.

Results

Wt1-hetdel mice show a consistent FSGS phenotype with proteinuria starting at age 4 wks progressing to sclerosis at age 12 wks.
Transcriptomic profiling of glomeruli by RNAseq discriminated 4wk from 12wk FSGS. Signaling pathway impact analysis of RNAseq data identified pathways predominantly dysregulated in early vs late FSGS disease phases. The ephrin signaling pathway was exclusively dysregulated in the sclerotic stage of FSGS.
Integrative analysis of Wt1 ChIPseq data from healthy and diseased mice and RNAseq data confirmed differential binding of Wt1 at differentially expressed genes relevant to ephrin signaling indicative of Wt1-mediated gene-regulatory reprogramming of ephrin pathway genes.
Exclusively in progressed FSGS, targeted proteomics showed reduced protein abundance of EphrinB1, an interactor of nephrin and key molecule to podocyte ephrin signaling. Ultrastructural investigation of EphrinB1 using STED microscopy confirmed co-localization of EphrinB1 with podocin, with clustering of EphrinB1 in presumed signaling hubs. EphrinB1 signals were specifically reduced in sclerotic and preserved in non-sclerotic glomerular areas, respectively.

Conclusion

Transcriptomic profiling differentiated signaling pathways predominantly dysregulated in the proteinuric vs. sclerotic stage of FSGS. Integration of transcriptomics with glomerular Wt1-ChIPseq provided unbiased insight into contribution of Wt1 to FSGS disease progression. The ephrin signaling pathway and specifically EphrinB1 were identified as a differentially expressed in progressed FSGS, affected by Wt1-mediated reprogramming, and reduced specifically in sclerotic glomeruli on the protein level

Funding

  • Government Support - Non-U.S.