Abstract: SA-PO476
Novel PC2 Regulation of Ezrin in Renal Epithelia Reveals Insight into ADPKD Cystogenesis
Session Information
- Cystic Kidney Diseases: Basic/Translational
November 09, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Genetic Diseases of the Kidneys
- 1001 Genetic Diseases of the Kidneys: Cystic
Authors
- Dixon, Eryn E., University of Maryland School of Medicine, Baltimore, Maryland, United States
- Leitch, Carmen C., University of Maryland School of Medicine, Baltimore, Maryland, United States
- Zaghloul, Norann A., University of Maryland School of Medicine, Baltimore, Maryland, United States
- Welling, Paul A., University of Maryland School of Medicine, Baltimore, Maryland, United States
- Woodward, Owen M., University of Maryland School of Medicine, Baltimore, Maryland, United States
Background
Ezrin plays the role of master scaffold of the apical compartment in epithelial cells and is critical in regulation of polarity, cytoskeleton organization, and protein trafficking. Ezrin regulation and the downstream consequences of its disruption have not been elucidated. Investigation into the initiating events of cystogenesis in autosomal dominant polycystic kidney disease (ADPKD) revealed a dramatic change in ezrin, following loss of polycystin-2 (PC2). ADPKD is caused by loss of function mutations in PKD1 and PKD2, which encode for transmembrane proteins PC1 and PC2, respectively.
Methods
Using an inducible Cre system (Pkd2fl/fl Pax8rtTA TeTOCre), PC2 loss in a three dimensional renal epithelial model resulted in decreased ezrin abundance. Furthermore, an in vivo mouse ADPKD model (Pkd2fl/fl Pax8rtTA TetOCre) of rapid cystogenesis exhibits significant changes in ezrin at the apical membrane of renal tubules after a short induction period of five days, and before the manifestation of cysts. Human ADPKD tissue also confirms changes in the structure of the apical compartment in emergent cystic cells, which correlated with significant alterations in the localization and abundance of ezrin in comparison to controls. A potential regulatory relationship between PC2 and ezrin is supported by experiments that demonstrated PC2 and ezrin interact in an overexpression system and share a similar phosphoinositide binding profile in a lipid overlay assay. Based on this novel regulatory relationship between PC2 and ezrin, as well as the antecedent loss of ezrin to cyst formation, human ezrin was overexpressed in the pkd2 morpholino pronephric cyst model of zebrafish. Increased expression of ezrin abolished the formation of pronephric cysts.
Results
The interaction profile of PC2 and ezrin, disruption of ezrin in Pkd2 inducible in vitro and in vivo model systems, changes in ADPKD patient tissue, and rescue of pronephric cysts in the pkd2 MO suggest there is a significant role of ezrin in renal cystogenesis.
Conclusion
Understanding the relationship of a master scaffold, ezrin, with PC2 in renal epithelial cells will help elucidate the mechanism of ADPKD cystogenesis and define important downstream pathways necessary for epithelial functions.
Funding
- NIDDK Support