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Abstract: SA-PO997

Extracellular Vesicles of Podocytes Impact Intraglomerular Signaling and Parietal Epithelial Cell (PEC) Activation

Session Information

Category: Glomerular Diseases

  • 1403 Podocyte Biology

Authors

  • Pausch, Alexander, Universitatsklinikum Hamburg-Eppendorf, Hamburg, Hamburg, Germany
  • Gathmann, Annika, Universitatsklinikum Hamburg-Eppendorf, Hamburg, Hamburg, Germany
  • Teicher, Kilian, Universitatsklinikum Hamburg-Eppendorf, Hamburg, Hamburg, Germany
  • Homeyer, Inka Christina, Universitatsklinikum Hamburg-Eppendorf, Hamburg, Hamburg, Germany
  • Wong, Milagros N., Universitatsklinikum Hamburg-Eppendorf, Hamburg, Hamburg, Germany
  • Obser, Anja, Universitatsklinikum Hamburg-Eppendorf, Hamburg, Hamburg, Germany
  • Deheshwar, Kian, Universitatsklinikum Hamburg-Eppendorf, Hamburg, Hamburg, Germany
  • Dryden, Kelly A., University of Virginia, Charlottesville, Virginia, United States
  • Wong, Hetty N., University of Pennsylvania, Philadelphia, Pennsylvania, United States
  • Wanner, Nicola, Universitatsklinikum Hamburg-Eppendorf, Hamburg, Hamburg, Germany
  • Lindenmeyer, Maja, Universitatsklinikum Hamburg-Eppendorf, Hamburg, Hamburg, Germany
  • Holzman, Lawrence B., University of Pennsylvania, Philadelphia, Pennsylvania, United States
  • Meyer-Schwesinger, Catherine, Universitatsklinikum Hamburg-Eppendorf, Hamburg, Hamburg, Germany
  • Ricklefs, Franz Lennard, Universitatsklinikum Hamburg-Eppendorf, Hamburg, Hamburg, Germany
  • Erdbruegger, Uta, University of Virginia, Charlottesville, Virginia, United States
  • Puelles, Victor G., Universitatsklinikum Hamburg-Eppendorf, Hamburg, Hamburg, Germany
  • Huber, Tobias B., Universitatsklinikum Hamburg-Eppendorf, Hamburg, Hamburg, Germany
  • Braun, Fabian, Universitatsklinikum Hamburg-Eppendorf, Hamburg, Hamburg, Germany
Background

Extracellular vesicles (EVs) have the ability to impact basic pathological processes such as malignant, metabolic and autoimmune diseases through intercellular signaling. However, we lack a concise knowledge about their role in kidney health and disease. Our study aims to characterize the intraglomerular signalling propagated by medium sized (mEVs) and small EVs (sEVs) shed by podocytes.

Methods

Using differential (ultra-)centrifugation we separated mEVs and sEVs from cell culture supernatants, kidney tissue and urine samples. Using Western Blot, immunofluorescence microscopy as well as image flow cytometry and cryo electron microscopy we investigated the release dynamics of podocyte-specific EVs in different models of murine podocyte damage in vitro and in vivo. Life microscopy and cross culture experiments were used to determine the effect of podocyte-specific EVs on parietal epithelial cells (PECs). To determine potential signaling factors we performed proteomic analysis of EV content.

Results

Podocytes shed medium-sized and small EVs detectable in culture supernatant, murine kidney tissue as well as the urine of healthy human volunteers. Upon podocyte damage in vitro, we detected an increase in EV release as a unified response with a size-shift in certain conditions revealed in Cryo-EM. Surprisingly, podocyte-specific EVs exerted different effects on the migratory behavior and proliferation of PECs depending on EV size and the initial insult to the podocyte. Proteomics revealed limited differences in the EV proteome in different stress conditions, with first candidate proteins potentially propagating the effect on PECs. In vivo, decreased EV release by podocytes resulted in reduced PEC activation and limited recruitment of macrophages in a model of crescentic nephritis.

Conclusion

Our study yields essential insights on podocyte-specific release of different sizes of extracellular vesicles, their protein contents and functional implications in health and upon podocyte damage. Ongoing experiments focus on further elucidating the impact of podocyte-specific release in vivo and the impact of knocking-out identified EV candidate proteins.