Abstract: TH-PO0160
Chemical Chaperones Improve PC1 Ciliary Trafficking and Rescue the Cystic Phenotype in ADPKD Mouse Three-Dimensional (3D) Spheroids
Session Information
- ADPKD and Cystic Kidney Disease - 1
October 22, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Genetic Diseases of the Kidneys
- 1201 Genetic Diseases of the Kidneys: Cystic (Monogenic)
Authors
- Hasan, Fatema, Yale School of Medicine, New Haven, Connecticut, United States
- Bhardwaj, Rishi, Yale School of Medicine, New Haven, Connecticut, United States
- Wendlinger, Sarah, Max-Delbruck-Centrum fur Molekulare Medizin in der Helmholtz-Gemeinschaft Experimental and Clinical Research Center, Berlin, BE, Germany
- Rehman, Michael, Yale School of Medicine, New Haven, Connecticut, United States
- Cordido, Adrian, Yale School of Medicine, New Haven, Connecticut, United States
- Somlo, Stefan, Yale School of Medicine, New Haven, Connecticut, United States
- Krappitz, Matteus, University of Colorado Anschutz Medical Campus School of Medicine, Aurora, Colorado, United States
- Fedeles, Sorin V., Yale School of Medicine, New Haven, Connecticut, United States
Background
ADPKD is characterized by progressive renal cyst formation that leads to kidney failure and arises from mutations in the PKD1 and PKD2 genes, encoding the proteins PC1 and PC2, respectively. Roughly a quarter of PKD1 mutations are missense, a subset of which are hypomorphic and produce reduced but residual levels of functional PC1. To suppress cyst formation, PC1 must fold properly, undergo cleavage at the GPS site, and traffic to the primary cilium—steps that hypomorphic mutations disrupt by causing PC1 misfolding. Here, we investigated whether chemical chaperones can rescue this misfolding. Using mouse primary and immortalized cells carrying orthologous PKD1 hypomorphic mutations—mild (R2216W; RW) and severe (E2766K; EK)—we examined the effects of chemical chaperones on PC1 cleavage, ciliary trafficking, and the cystic phenotype in vitro.
Methods
Primary renal cells were isolated from hypomorphic mouse models (RW/flox;Pax8;TetOCre and EK/flox;Pax8;TetOCre) and treated with doxycycline to inactivate the floxed allele (to generate RW/- and EK/- cells). To assess PC1 cleavage, 2D cultures were treated with chaperones (4-PBA and/or TUDCA) and analyzed by immunoblotting. To measure cyst size, cells were seeded in matrigel, treated with chaperones, and quantified. To evaluate ciliary trafficking, immortalized cell lines carrying a 3HA.Halo tag at the C-terminus of PC1-RW/- were treated with chaperones and co-stained with anti-HA and the ciliary marker Arl13b.
Results
Pkd1 hypomorphic cells formed cysts that were smaller than Pkd1 knockout spheroids, consistent with a genotype–phenotype correlation. At the protein level, RW/- cells exhibited a partial PC1 cleavage defect, whereas EK/- cells showed a complete cleavage defect. Minimal PC1 was detectable in the cilia of lines RW/- cells. TUDCA alone or in combination with 4-PBA significantly reduced cyst size in RW/- spheroids. Moreover, 4-PBA and TUDCA—individually and combined—increased both full-length and cleaved PC1 in RW/- cells and enhanced PC1 ciliary trafficking in RW/- 3HA.Halo cells. Importantly, no effect of the chaperones was seen in the complete absence of PC1 (Pkd1-/-) denoting allele specific effects.
Conclusion
Chemical chaperones reduced cyst size in hypomorphic Pkd1 spheroids, in part by improving PC1 cleavage and ciliary trafficking, suggesting a promising therapeutic avenue for ADPKD.
Funding
- Other U.S. Government Support