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Abstract: TH-PO1069

Using Drosophila Nephrocytes to Identify Specific States of Podocyte Disease Correlated with a Dysregulation of Insulin-Dependent Signals

Session Information

Category: Glomerular Diseases

  • 1204 Podocyte Biology

Authors

  • Kuehne, Lucas, University Hospital Cologne, Cologne, Germany
  • Odenthal, Johanna, University Hospital Cologne, Cologne, Germany
  • Schermer, Bernhard, University Hospital Cologne, Cologne, Germany
  • Benzing, Thomas, University of Cologne, Köln, Germany
  • Brinkkoetter, Paul T., University Hospital Cologne, Cologne, Germany
Background

Insulin signaling with its relation to metabolic cascades, including the regulation of anabolic and catabolic processes via mTOR and the FoxO transcription factor, is one of the most complex signaling networks, playing a key role in podocyte health and disease. This study aims to test whether Drosophila nephrocytes can be used to efficiently screen for dysregulated insulin signaling pathways in different forms of steroid resistant nephrotic syndrome (SRNS).

Methods

Several mutations that are known to cause SRNS have been characterized in Drosophila and can be modeled using the GAL4-UAS-system. These mutations lead to a dysfunction in different cellular compartments, e.g. the mitochondria. Here, we use the Drosophila nephrocytes to screen for dysregulated insulin signaling in specific states of podocyte disease. The phenotypic characterization is based on Tracer-Uptake-Assays, IF-staining and electron microscopy, while a dysregulated insulin signaling can be observed via qPCR, Western Blot and a FoxO-mCherry-reporter line.

Results

The correlation between mitochondrial dysfunction and hyperactive insulin signaling, based on a cell-specific Prohibitin-2-knockdown, could be confirmed in Drosophila nephrocytes. While the Prohibitin-knockdown lead to a functional phenotype with a reduced uptake of FITC-albumin, there were no obvious morphological changes. This phenotype could be rescued by an inhibition of the mTOR kinase via rapamycin.

Conclusion

Drosophila nephrocytes show a clear correlation between mitochondrial dysfunction, initiated by a Prohibitin-knockdown, and hyperactive insulin signaling. Consequently, the nephrocytes can be used as an efficient in vivo model to characterize insulin-dependent signaling pathways in podocytes.

Funding

  • Government Support - Non-U.S.