Kidney Week

Abstract: SA-PO605

Ryanodine Receptor 3 (RYR3) as a Candidate Modifier of Aneurysm Formation in ADPKD

Session Information

• Cystic Kidney Diseases: Genetic Causes, Modifiers, and Extrarenal Manifestations
  October 26, 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

Authors

• Roy, Kasturi, Yale University School of Medicine, New Haven, Connecticut, United States

Kasturi Roy, PhD

• Gulati, Ashima, Children's National Hospital, Washington, District of Columbia, United States

Ashima Gulati, MD, PhD, FASN

• Gu, Jianlei, Yale University School of Medicine, New Haven, Connecticut, United States

Jianlei Gu

• Shaw, Melissa M., Yale University School of Medicine, New Haven, Connecticut, United States

Melissa M. Shaw

• Sun, Zhaoxia, Yale University School of Medicine, New Haven, Connecticut, United States

Zhaoxia Sun, PhD

• Besse, Whitney, Yale University School of Medicine, New Haven, Connecticut, United States

Whitney Besse, MD

• Watnick, Terry J., University of Maryland, College Park, Maryland, United States

Terry J. Watnick, MD

• Somlo, Stefan, Yale University School of Medicine, New Haven, Connecticut, United States

Stefan Somlo, MD

Background

Autosomal dominant polycystic kidney disease (ADPKD) is the primary inherited cause of kidney failure, caused by mutations in PKD1 or PKD2. Among its extrarenal manifestations, intracranial aneurysms (ICA) pose a significant mortality risk, with a prevalence approximately five times higher than the general population, and further elevated when a family member has ADPKD and ICA. We hypothesize that the development of ICA in ADPKD involves one or more genetic modifiers in addition to the germline PKD mutation.

Methods

To investigate this hypothesis, we established a cohort comprising individuals with ADPKD and ICA, alongside controls. Whole exome sequencing (WES) was performed to identify germline PKD mutations and to assess for enrichment of genes or pathways with rare genetic variants in those with ADPKD and ICA vs. control cases. To investigate candidate targets, a zebrafish model with pkd2 mutation (pkd2^hi4166Tg) was employed. Candidate modifiers were inactivated using CRISPR/Cas9 system and scored for intracranial hemorrhage (IH) without knowledge of genotype.

Results

We identified RYR3 as having increased occurrence of rare predicted deleterious missense variants in ICA-ADPKD cases compared to ADPKD controls without known ICA (p=2.75e-8; OR=11.6). Given this enrichment of RYR3 variants within the cohort, we proceeded with a secondary validation screen in zebrafish models. ryr3 was inactivated by CRISPR/Cas9 in heterozygous pkd2^hi4166Tg fish and both acute and germline transmission of ryr3 knockout (ryr3^-/-) were examined. Acute ryr3^-/- resulted in a 2-fold increase in brain bleeds while germline ryr3^-/-resulted ~4-fold increase in brain bleeds in heterozygous pkd2^hi4166Tg fish compared to respective ryr3^+/+ controls observed at 56 hpf. Imaris analysis showed a 0.6-fold reduction in vascular branching in ryr3^-/-; pkd2^hi4166Tg/+ fish compared to ryr3^+/+; pkd2^hi4166Tg/+ fish.

Conclusion

RYR3 is a potential modifier of vascular integrity in the context of ADPKD mutations. Further replication and validation studies are warranted.

Funding

• Other U.S. Government Support