Kidney Week

Abstract: FR-PO0092

Activation of CFTR Suppresses Calcium-cAMP Signaling and Cyst Growth in ARPKD

Session Information

• ADPKD and Cystic Kidney Disease - 2
  October 23, 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

• Sharma, Abhishek, Johns Hopkins Medicine, Baltimore, Maryland, United States

Abhishek Sharma, PhD

• Sharma, Tanvi, Johns Hopkins Medicine, Baltimore, Maryland, United States

Tanvi Sharma, PhD

• Afshani, Masoud, Johns Hopkins Medicine, Baltimore, Maryland, United States

Masoud Afshani, PhD, DVM

• Guggino, William B., Johns Hopkins Medicine, Baltimore, Maryland, United States

William B. Guggino, PhD

• Cebotaru, Liudmila, Johns Hopkins Medicine, Baltimore, Maryland, United States

Liudmila Cebotaru, MD

Background

ARPKD is a fibrocystic disease of liver and kidney which usually occurs in neonates. FPC protein encoded by the PKHD1 gene, is the major ciliary signaling protein whose dysfunction causes ARPKD. In the present study, the role of CFTR in cyst development and in intracellular Calcium regulation was studied which may contribute to ARPKD pathology.

Methods

In the present study WT (C57Bl/6) and ARPKD (Pkhd1^{del3-4/del3-4}) mice models were used and treated with CFTR modulators (VX809 and VX445). Mouse liver tissues were analyzed by H&E staining and confocal imaging for CFTR localization in cholangiocytes. Primary cholangiocyte cells were isolated from WT and ARPKD mice, followed by treatment with CFTR modulators and the inhibitor-172. Cell proliferation was checked using BrdU assays. Intracellular Calcium and cAMP signaling were measured by Fura-2 AM and cAMP assay respectively. Cyst growth was examined in 3D Matrigel cyst models.

Results

CFTR modulators caused a reduction in cyst size as well as the liver body weight ratio. Confocal images confirm a decrease in cyst size and change in the polarity of CFTR from apical to basolateral membranes. In primary cells, protein expression showed alteration in CFTR protein in ARPKD cholangiocytes. Enhanced expression of the proliferative protein, Ki67, in ARPKD cholangiocytes was observed which was validated by BrdU proliferation assay. Fura-2AM Calcium assay showed increased intracellular Calcium with decreased IP3R and increased STIM1 & SERCA2 expression. Higher cAMP levels and increased AC3 expression was observed in ARPKD cholangiocytes which causes expansion of cyst growth ARPKD cholangiocytes. CFTR modulators restored CFTR maturation which normalized the elevated intracellular Calcium levels as well as intracellular cAMP signaling. Modulators also reduced the proliferative signaling, Ki67, protein expression and reduced cyst size. However, inhibition of CFTR by the inh-172 further made the disease phenotype worse as noted by increased intracellular Calcium levels and increased Ki67 proliferation.

Conclusion

Overall, results showed that CFTR may act as a key player in intracellular Calcium & cAMP signaling which contributes to ARPKD cyst growth. Activating CFTR, rather than inhibiting it, may be a promising therapeutic way to limit ARPKD disease progression

Funding

• NIDDK Support