Abstract: FR-PO248
Refining the Developmental Window That Determines Different Kinetics of Cystogenesis After Pkd2 Inactivation in Mice
Session Information
- Genetic Diseases of the Kidneys: Cystic - II
November 04, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
Abstract Time: 10:00 AM - 12:00 PM
Category: Genetic Diseases of the Kidneys
- 1101 Genetic Diseases of the Kidneys: Cystic
Authors
- Outeda, Patricia, University of Maryland School of Medicine, Baltimore, Maryland, United States
- Watnick, Terry J., University of Maryland School of Medicine, Baltimore, Maryland, United States
Background
Classic Autosomal Dominant Polycystic Kidney Disease (ADPKD) is caused by mutations in PKD1 or PKD2. In mice, early inactivation of Pkd1 results in rapid and severe cyst formation within 2 weeks. In contrast, inactivation of Pkd1 in adult kidneys yields slow cystic progression over several months. A detailed time course of Pkd1 inactivation revealed that the switch in the kinetics of cyst formation occurs between postnatal day (P) 13 and P14. Although it is assumed that a similar switch occurs for Pkd2 the kinetics of cyst formation in Pkd2 has never been described. Here we inactivate Pkd2 at different time points to define the critical window that determines the kinetics of cyst formation after Pkd2 depletion.
Methods
We used the Pkd2Fl/Fl; Pax8rtTA; Tet-O-Cre mouse model and induced Cre recombinase with doxycycline at different time points (from P10 to P15). We harvested kidneys at 10 days and at 60 days after inactivation. To determine the severity of cystogenesis we analyzed kidney-to-body weight ratio (KW/BW ratio) and cystic index (CI). We performed immunofluorescence staining (IF) using segment-specific markers and performed Masson's Trichrome staining and IF and western blot (WB) to detect fibrosis.
Results
Gross examination and histopathological analysis revealed that kidneys inactivated at P10 and harvested at P20 were the largest and most cystic, while kidneys inactivated at and after P14 showed KW/BW ratio and CI closest to non-induced pups at the same age. In contrast, mild dilation of distal tubules was observed in kidneys induced at P14 and harvested at P24. Only a small number of cysts was detected in kidneys induced at P15 and harvested at P25, but if harvested at P60 males showed massive cyst formation in both the proximal and distal tubules while females showed few scattered distal cysts. We could not detect collagen depositions in kidneys induced at P15 and harvested at P60 but we observed an increased number of myofibroblasts around cysts and increased expression of α-SMA by WB especially in males indicating that although fibrosis was not observed remodeling of extracellular matrix proteins had been initiated.
Conclusion
Our study revealed that the critical developmental window that determines the kinetics of cysts formation in mouse models is similar for both Pkd1 and Pkd2 genes.
Research Supported by NIDDK-U54DK126114
Funding
- NIDDK Support