Abstract: PO1639
APOL1 Cytoxicity Is Variant and Dose Dependent
Session Information
- Genetic Diseases of the Kidneys: Non-Cystic - 2
October 22, 2020 | Location: On-Demand
Abstract Time: 10:00 AM - 12:00 PM
Category: Genetic Diseases of the Kidneys
- 1002 Genetic Diseases of the Kidneys: Non-Cystic
Authors
- Olabisi, Opeyemi A., Duke University School of Medicine, Durham, North Carolina, United States
- Datta, Somenath, Duke University School of Medicine, Durham, North Carolina, United States
- Zhang, Jiayue, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States
- Moore, Savannah, Massachusetts General Hospital, Boston, Massachusetts, United States
- Petitpas, Kaitlyn M., Massachusetts General Hospital, Boston, Massachusetts, United States
- Mohamed, Adam, Massachusetts General Hospital, Boston, Massachusetts, United States
- Zahler, Nathan, Icagen Inc, Durham, North Carolina, United States
- Pollak, Martin R., Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States
Background
Two coding renal risk variants (RRVs) of APOL1 gene (G1 and G2), are associated with large increases in chronic kidney disease (CKD) rates among populations of recent African descent, but the underlying molecular mechanisms are unknown. In vitro mammalian cell cultures models are widely used to study cytotoxicity of RRVs, but results have been contradictory. It remains unclear whether cytotoxicity is RRVs-dependent or driven solely by variant-independent overexpression. It is also unknown whether the reference APOL1 allele, G0 could prevent cytotoxicity of RRVs.
Methods
We generated tetracycline-inducible APOL1 expression in HEK293 cells and examined the effects of increased expression of APOL1 (G0,G1,G2,G0G0,G0G1,or G0G2) on known cytotoxicity phenotypes including reduced cell viability, increased cell swelling, cellular potassium loss, aberrant protein phosphorylation, and dysregulated energy metabolism. Furthermore, whole genome transcriptome analysis was performed to discover deregulated canonical pathways.
Results
At moderate expression, RRVs but not G0 caused cytotoxicity. RRVs-induced cytotoxicity is dose-dependent and is not reduced by co-expression of G0. RRVs also have dominant effects on canonical pathways relevant for cellular stress response.
Conclusion
In HEK293 cells, RRVs have dominant gain-of-toxic function that worsens with increasing expression. These observations suggest that high steady state levels of RRVs may underlie cellular injury in APOL1 nephropathy, and that interventions that reduce RRVs expression in kidney compartments may be effective for mitigating APOL1 nephropathy.
Funding
- Other NIH Support