Kidney Week

Abstract: FR-PO553

KCNJ16-Depleted Kidney Organoids Recapitulate Tubulopathy and Lipid Recovery with Statin Treatment

Session Information

• Fluid, Electrolyte, and Acid-Base Disorders: Basic
  October 25, 2024 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Fluid, Electrolytes, and Acid-Base Disorders

• 1101 Fluid, Electrolyte, and Acid-Base Disorders: Basic

Authors

• van Genderen, Anne Metje, Universiteit Utrecht Utrechts Instituut voor Farmaceutische Wetenschappen, Utrecht, Utrecht, Netherlands

Anne Metje van Genderen, MS, MSc

• Sendino Garví, Elena, Universiteit Utrecht Utrechts Instituut voor Farmaceutische Wetenschappen, Utrecht, Utrecht, Netherlands

Elena Sendino Garví, MSc

• van Slobbe, Gijs Jacobus Johannes, Universiteit Utrecht Utrechts Instituut voor Farmaceutische Wetenschappen, Utrecht, Utrecht, Netherlands

Gijs Jacobus Johannes van Slobbe, MSc

• De Baaij, Jeroen H.F., Radboud Universitair Medisch Centrum, Nijmegen, Netherlands

Jeroen H.F. De Baaij, PhD

• Hoenderop, Joost, Radboud Universitair Medisch Centrum, Nijmegen, Netherlands

Joost Hoenderop, PhD

• Janssen, Manoe J., Universiteit Utrecht Utrechts Instituut voor Farmaceutische Wetenschappen, Utrecht, Utrecht, Netherlands

Manoe J. Janssen, MS, PhD

• Masereeuw, Rosalinde, Universiteit Utrecht Utrechts Instituut voor Farmaceutische Wetenschappen, Utrecht, Utrecht, Netherlands

Rosalinde Masereeuw, PhD

Background

The KCNJ16 gene has recently been associated with a kidney tubulopathy phenotype, including disturbed acid-base homeostasis, hypokalemia and altered renal salt transport as main disease features. KCNJ16 encodes for Kir5.1, which together with Kir4.1 constitutes a potassium channel located in the basolateral membrane of the tubular kidney cells. Despite previous in vitro and rodent models provided with mechanistical links between Kir5.1 and the recently described disease phenotype, the pathophysiological mechanisms of the disease are still poorly understood. In this project, we aimed to generate a characterize a novel advanced kidney organoid model that better recapitulates the disease phenotype to further investigate the pathophysiological mechanisms underlying the disease.

Methods

For this we used CRISPR-Cas9 to generate heterozygous and a compound heterozygous KCNJ16 mutant cell lines from healthy human induced pluripotent stem cells (iPSC). Both the healthy (KCNJ16^WT) and mutated (KCNJ16^+/- and KCNJ16^-/- iPSC lines were differentiated into kidney organoids using a 25-day differentiation protocol and maturation in an air-liquid interface environment.

Results

After successful depletion of Kir5.1, KCNJ16-depleted kidney organoids showed transcriptomic impairment of key electrolyte and water-balance transporters such as AQP1, NBC1, SNAT-3 and PEPCK. We also observed cysts formation (p<0.01) and staining with the bodipy probe and collagen-I revealed lipid droplet accumulation (p<0.001) and fibrosis (p<0.01). Following these results, we performed a large scale and a glutamine tracer flux metabolomics analysis and found that KCNJ16-/- depleted organoids display TCA cycle and lipid metabolism impairments when compared to KCNJ16^WT (p<0.01-0.0001), particularly at glutamine and citrate levels. By testing different drug compounds on the kidney organoids, we discovered that treatment with statins reversed the lipid droplet accumulation (p<0.01-0.0001) and collagen I deposition (p<0.01) in KCNJ16^-/- kidney organoids.

Conclusion

In conclusion, mature kidney organoids represent a relevant in vitro model for investigating Kir5.1 function, providing novel molecular targets for this genetic tubulopathy and identifying statins as a potential therapeutic strategy.

Funding

• Government Support – Non-U.S.