Abstract: SA-PO443
Kidney Podocytes Generate Autonomous Calcium Transients That Regulate Glomerular Capillary Tuft Formation
Session Information
- Development and Regenerative Medicine
November 09, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Development, Stem Cells, and Regenerative Medicine
- 500 Development, Stem Cells, and Regenerative Medicine
Authors
- Djenoune, Lydia, Massachusetts General Hospital, Charlestown, Massachusetts, United States
- Drummond, Iain A., Massachusetts General Hospital, Charlestown, Massachusetts, United States
Background
Podocytes are critical to maintaining the glomerular filtration barrier; mutations in nephrotic syndrome genes lead to defects in barrier function and can affect podocyte calcium signaling. The role of calcium signaling during podocyte development in vivo remains unknown however.
Methods
Using the genetically encoded biosensor GCaMP6s expressed in zebrafish podocytes we quantified intracellular calcium dynamics in differentiating podocytes in vivo.
Results
Immature podocytes (2.5 days post fertilization (dpf)) generate calcium transients that correlate with cell motility and podocyte interactions with forming glomerular capillaries. Calcium transients persist until 4 dpf and are absent when glomerular barrier formation is complete. Calcium transients are not affected by deficiencies in heartbeat (tnnt2 morphant), endothelium (cloche mutant) or endoderm (sox32 morphant), suggesting they may be generated cell autonomously. Dissociated, intact GCaMP6s-expressing glomeruli in short term in vitro culture continue to exhibit calcium transients similar to in vivo podocytes, indicating the transients are autonomously generated. Inhibitors of SERCA or IP3 receptor calcium-release channels block calcium transients, while lanthanum and medium EGTA are ineffective, indicating the source of calcium is podocyte ER stores. Blocking calcium release impacts glomerular shape and cell organization, suggesting further that calcium signaling guides glomerular morphogenesis.
Conclusion
Our results establish cell autonomous calcium signaling as a prominent feature of podocyte differentiation and present a model to decipher mechanisms leading to proper glomerular morphogenesis.
Funding
- NIDDK Support