Abstract: SA-PO210

In Vivo Investigation of Calcium Dynamics in Developing Podocytes during Glomerular Morphogenesis

Session Information

  • Glomerular: Cell Biology
    November 04, 2017 | Location: Hall H, Morial Convention Center
    Abstract Time: 10:00 AM - 10:00 AM

Category: Glomerular

  • 1003 Glomerular: Cell Biology

Authors

  • Djenoune, Lydia, Massachusetts General Hospital , Charlestown, Massachusetts, United States
  • Tomar, Ritu, Massachusetts General Hospital , Charlestown, Massachusetts, United States
  • Merkel, Erin, Massachusetts General Hospital , Charlestown, Massachusetts, United States
  • Drummond, Iain A., Massachusetts General Hospital , Charlestown, Massachusetts, United States
Background

Podocytes are highly specialized epithelial cells in the kidney glomerulus that play critical roles in maintaining the glomerular filtration barrier. Nephrotic syndrome genes, including TrpC6 and PLCe1, affect podocyte calcium signaling. However, the role of calcium signaling during podocyte development in vivo remains unknown.

Methods

Here we aim at understanding the role of calcium signaling during glomerular development using live imaging of zebrafish.

Results

Live imaging showed that immature podocytes (48 hours post fertilization) are dynamic and interact with the dorsal aorta to form glomerular capillaries. By 4 days post fertilization (dpf) podocytes stabilize and the filtration barrier is functionally mature. Using the calcium biosensor GCaMP3, we observed spontaneous intracellular calcium transients in podocytes at early stages (2-3 dpf) of development in the zebrafish larva which were silenced by 4 dpf suggesting a role for calcium signaling in podocyte maturation. To determine the source of calcium, larvae were treated with calcium inhibitors and we observed that calcium transients were blocked by cyclopiazonic acid, thapsigargin and 2APB but not by cilnidipine or nifedipine, indicating calcium release from intracellular stores. plce1 knockdown resulted in podocyte defects, disorganized capillaries, and loss of podocin expression suggesting a requirement for calcium signaling in podocyte differentiation. Using an unbiased whole glomeruli RNAseq transcriptome approach we identified multiple candidate signaling receptors potentially responsible for developmental podocyte calcium signaling.

Conclusion

These studies will help to identify new targets for intervention in glomerular diseases and establish zebrafish as a model for glomerular diseases caused by impaired calcium signaling.

Funding

  • NIDDK Support