Kidney Week

Abstract: FR-PO0111

Induced Pluripotent Stem Cell (iPSC)-Derived Endothelial Cell Model for the Study of APOL1-Mediated CKD Pathogenesis

Session Information

• Hereditary Glomerular and Tubulointerstitial Kidney Diseases
  October 23, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Genetic Diseases of the Kidneys

• 1202 Genetic Diseases of the Kidneys: Non-Cystic (Complex and Non-Cystic Monogenic)

Authors

• Cam, Nurdan, Cleveland Clinic, Cleveland, Ohio, United States

Nurdan Cam, MSc

• Bartolomeo, Korey, Cleveland Clinic, Cleveland, Ohio, United States

Korey Bartolomeo, DO

• Raheb Khelo, Joy, Cleveland Clinic, Cleveland, Ohio, United States

Joy Raheb Khelo, MD

• Onur, Omer Enes, Cleveland Clinic, Cleveland, Ohio, United States

Omer Enes Onur, MD

• Tran, Uyen, Cleveland Clinic, Cleveland, Ohio, United States

Uyen Tran

• Wessely, Oliver, Cleveland Clinic, Cleveland, Ohio, United States

Oliver Wessely, PhD

• Sedor, John R., Cleveland Clinic, Cleveland, Ohio, United States

John R. Sedor, MD, FASN

• O'Toole, John F., Cleveland Clinic, Cleveland, Ohio, United States

John F. O'Toole, MD

Background

Chronic Kidney Disease (CKD) affects over 20 million Americans. African Americans are disproportionately impacted due in part to APOL1 high-risk variants (G1 and G2). While APOL1’s role in podocyte injury is well-documented, emerging evidence suggests that endothelial cell (EC) dysfunction plays a critical role in APOL1-mediated nephropathies. Recent studies have proposed that APOL1 pyroptotic pathways, plasma membrane localization, and cation flux activity may contribute to cellular injury; however, these mechanisms remain incompletely understood in endothelial cells.

Methods

To investigate this phenomenon, we established an iPSC-derived EC model carrying the APOL1 reference (G0) and high-risk (G1, G2) variants. EC differentiation was characterized using qRT-PCR, Western blot analyses of endothelial markers, transmembrane resistance and tube formation assays. SYTOX assays were used to evaluate IFN-γ-induced, variant-dependent effects on cell viability. Surface biotinylation assays were performed to assess APOL1 plasma membrane localization. In addition, K+ conductance (FluxOR II assays) was measured in APOL1-expressing iPSC-derived ECs.

Results

APOL1 variant iPSC-derived ECs express key endothelial markers, including PECAM1, EMCN, PLVAP, and vWF. Following IFN-γ stimulation, APOL1 was detectable at the plasma membrane in BJFF6 iPSC-derived ECs carrying G0, G1, and G2 variants. However, IFN-γ exposure did not significantly impact cell viability or endothelial cell transcriptional differentiation markers in a variant-dependent manner. Moreover, in contrast to studies in HEK293 cells, FluxOR II analysis did not reveal APOL1-induced changes in K+ flux across genotypes under the tested conditions.

Conclusion

These findings establish an iPSC-derived EC model for studying APOL1 biology and demonstrate IFN-γ-induced APOL1 plasma membrane localization in endothelial cells. Under the tested experimental conditions, robust and consistent K+ flux responses were not observed, highlighting the need to identify mechanisms regulating APOL1-associated ion flux activity across additional cellular models and haplotype backgrounds.

Funding

• NIDDK Support