Kidney Week

Abstract: TH-PO582

Investigating Organoid Characteristics of CoQ10-Deficient Glomerulopathy

Session Information

• Glomerular Diseases: Omics, Biomarkers, and Tools
  October 24, 2024 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• 1401 Glomerular Diseases: Mechanisms, including Podocyte Biology

Authors

• Yu, Seyoung, Yonsei University College of Medicine, Seodaemun-gu, Seoul, Korea (the Republic of)

Seyoung Yu, MS

• Hildebrandt, Friedhelm, Boston Children's Hospital, Boston, Massachusetts, United States

Friedhelm Hildebrandt, MD

• Gee, Heon Yung, Yonsei University College of Medicine, Seodaemun-gu, Seoul, Korea (the Republic of)

Heon Yung Gee, MD, PhD

Background

Monogenic causes account for 11-30% of steroid-resistant nephrotic syndrome (SRNS) cases in children. Genes involved in the biosynthesis of coenzyme Q₁₀ (CoQ₁₀), such as PDSS2, COQ2, COQ6, and ADCK4, are known to cause SRNS and focal segmental glomerulosclerosis (FSGS). CoQ₁₀, located in the mitochondrial inner membrane, is crucial for supporting the electron transport chain in oxidative phosphorylation and for protecting against oxidative stress. While CoQ₁₀-deficient glomerulopathy can be partially treated with CoQ₁₀ supplements, the effectiveness of this treatment varies and has limitations. We developed an in vitro model system of CoQ₁₀-deficient glomerulopathies to study drug effects through detailed manipulations, which facilitates a better understanding of the disease and the creation of more effective treatments

Methods

We generated CoQ₁₀-deficient kidney organoids from human induced pluripotent stem cells (iPSCs) using the well-established in vitro induction protocol. To establish CoQ₁₀-deficient human iPSCs, we used synthetically generated gRNAs targeting PDSS2, COQ2, COQ6, ADCK4 along with Cas9 protein. We performed immunostaining and light microscopy analysis to evaluate the extent of their differentiation. We also observed mitochondrial morphology to investigate the phenotypic characteristics due to CoQ₁₀ deficiency.

Results

Gene ablation of CoQ₁₀-deficient iPSCs was confirmed through Sanger sequencing. CoQ₁₀-deficient kidney organoids expressed positive kidney markers and successfully differentiated into nephrons. To model glomerulopathy in these organoids, we verified the expression of podocyte markers and confirmed their development using electron microscopy. The podocytes displayed primary processes and cell-cell junctions, resembling the early stages of foot process formation. There were no significant differences in podocyte development between control and CoQ₁₀-deficient kidney organoids. However, examining the ultrastructure of podocytes in CoQ₁₀-deficient kidney organoids revealed abnormal mitochondria, characterized by hyperproliferation and increased size.

Conclusion

In conclusion, we have generated a model of CoQ₁₀-deficient glomerulopathy using kidney organoids, demonstrating abnormal mitochondrial phenotypes. This system provides a valuable platform for testing potential drug therapies and advancing treatment options for this condition.