Kidney Week

Abstract: TH-PO458

Adeno-Associated Virus 1 (AAV1) CFTR Gene Therapy Successfully Reduces Cysts in a Mouse Model of Autosomal Dominant Polycystic Kidney Disease

Session Information

• Cystic Kidney Diseases: Clinical Assessment and Therapeutic Directions
  October 24, 2024 | 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: Cystic

Author

• Cebotaru, Liudmila, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States

Liudmila Cebotaru, MD

Background

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by the formation of multiple large cysts that lead to end-stage renal disease by the sixth decade of life. Current therapies for ADPKD involve treatment of the symptoms associated with kidney disease and/or organ transplantation. Cyst growth involves fluid secretion into the cyst lumen through the action of CFTR, located at the luminal membrane. We showed that CFTR correctors such as VX-809 alter the location of CFTR in cystic epithelia from the apical to the basolateral membrane, thereby reducing cyst formation. Here, we propose the novel hypothesis that a gene therapy based on CFTR can prove effective in reducing kidney damage in ADPKD.

Methods

To provide data showing that kidney transduction via systemic delivery is feasible, approximately 1-month-old, Pkd1^{R3277C/R3277C} mice were injected intraperitonially with 2 × 10¹² VP/kg of AAV1 containing either GFP or Δ27-264CFTR, a truncated version of CFTR that increases expression of endogenous CFTR via biomolecular interaction with endogenous CFTR defined as transcomplementation. Animals were necropsied 2 months after treatment and the kidney tissue was anaylised by immunoflourescence microscopy and H&E staining. Also the vector genome and DNA expression was quantified by real time PCR.

Results

The cyst area and size were less in the CFTR- compared to GFP-vector treated animals. We detected vector genomes at >4x10⁵ vector genomes/ug DNA and mRNA expression at 4-8x10⁴ copies/ug DNA after vector instillation. Tissues were co-stained with either NHE3 or ENaC to highlight proximal or collecting duct expression, respectively. Expression of GFP and CFTR above background levels consistent with protein expression were generated by both vectors. We detected more GFP in the vector-treated cystic cells compared to surrounding tissue suggesting that AAV1 is more specific for cysts than the cells surrounding the cysts. We detected more CFTR IF at the basolateral membrane in AAV1-CFTR treated kidneys suggesting that CFTR was restored to its normal location.

Conclusion

These experiments demonstrate convincingly that kidneys of RC/RC animals can be transduced by AAV1 and that phenotypic correction of defective function can be achieved by over expression of CFTR. Also the data suggests that CFTR plays a critical role in ADPKD.

Funding

• NIDDK Support