Kidney Week

Abstract: FR-PO0654

Novel Gene Therapy for ADPKD Based on CFTR

Session Information

• Cystic Kidney Diseases: Basic and Translational Research
  November 07, 2025 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Genetic Diseases of the Kidneys

• 1201 Genetic Diseases of the Kidneys: Monogenic Kidney Diseases

Authors

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

Liudmila Cebotaru, MD

• Ciobanu, Cristian, Johns Hopkins Medicine, Baltimore, Maryland, United States

Cristian Ciobanu, MD

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

Abhishek Sharma, PhD

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

Masoud Afshani, PhD, DVM

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

Tanvi Sharma, PhD

Background

To overcome the challenges of developing a gene therapy for ADPKD, we focused on the surface receptors expressed in cystic epithelia. We detected altered localization in the cystic epithelium of wheat germ agglutinin, WGA, staining of sialic acid glycoproteins that facilitates the transduction of AAV1.

Methods

We injected Pkd1^{R3277C/R3277C} ADPKD mice i/p with AAV1 containing either a GFP or a truncated form of CFTR (Δ27-264) vector. Δ27-264 CFTR, when expressed exogenously in cells containing wildtype (WT) CFTR, bind to endogenous CFTR and increase the expression and function. We tested a second truncation mutant of CFTR containing the first nucleotide binding domain (NBD1) and the regulatory domain (R) (NBD1R) by transfection. We used a model ADPKD proximal tubule (PT) cell line, PN(Pkd1-knockout) and PH (heterozygote control). The NBD1R was transfected in cysts or cells evaluating the area and number of cysts or the protein expression by western, co-immunoprecipitation (co-IP) and immunofluorescence (IF). Staining with Maackia amurensis lectin or with Sambucus nigra lectin that are specific for α2,3- and α2,6-N-linked sialic acids was done.

Results

In mice treated with AAV1 Δ27-264 CFTR the cyst area and number were significantly reduced compared to untreated and those receiving the GFP. We detected vector genomes and mRNA expression only in their corresponding CFTR or GFP vector-treated mice. Co-staining for GFP and CFTR with either NHE3 or ENaC, indicating PT or CD expression. CFTR IF was increased in the basolateral membrane in CFTR treated mice reducing cyst size and number by reducing the secretory phenotype responsible for accumulating fluid in the cyst lumen.
The NBD1R transfected into PN cells increased WT CFTR protein expression, reduced cyst size, lowered cAMP levels and ER-Ca⁺² release to a greater extent compared with transfection of Δ27-264 CFTR.

Conclusion

These data suggest that cysts have altered sialic residues making them prime targets for AAV1 gene therapy offering an exciting prospect for ADPKD gene therapy. We also show that transcomplementation using truncated versions of CFTR alter the trafficking of WT-CFTR to basolateral membrane thereby promoting an absorptive phenotype and reducing cyst size. Our sugests strongly that the truncated form of CFTR delivered with AAV1 is a strong candidate for gene therapy for ADPKD.

Funding

• NIDDK Support

Digital Object Identifier (DOI)

• doi: 10.1681/ASN.202508tz2tcd