APOL1-mediated monovalent cation transport contributes to APOL1-mediated podocytopathy in kidney disease
Somenath Datta, … , Christopher B. Newgard, Opeyemi A. Olabisi
Somenath Datta, … , Christopher B. Newgard, Opeyemi A. Olabisi
Published January 16, 2024
Citation Information: J Clin Invest. 2024;134(5):e172262. https://doi.org/10.1172/JCI172262.
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APOL1-mediated monovalent cation transport contributes to APOL1-mediated podocytopathy in kidney disease

Abstract

Two coding variants of apolipoprotein L1 (APOL1), called G1 and G2, explain much of the excess risk of kidney disease in African Americans. While various cytotoxic phenotypes have been reported in experimental models, the proximal mechanism by which G1 and G2 cause kidney disease is poorly understood. Here, we leveraged 3 experimental models and a recently reported small molecule blocker of APOL1 protein, VX-147, to identify the upstream mechanism of G1-induced cytotoxicity. In HEK293 cells, we demonstrated that G1-mediated Na+ import/K+ efflux triggered activation of GPCR/IP3–mediated calcium release from the ER, impaired mitochondrial ATP production, and impaired translation, which were all reversed by VX-147. In human urine-derived podocyte-like epithelial cells (HUPECs), we demonstrated that G1 caused cytotoxicity that was again reversible by VX-147. Finally, in podocytes isolated from APOL1 G1 transgenic mice, we showed that IFN-γ–mediated induction of G1 caused K+ efflux, activation of GPCR/IP3 signaling, and inhibition of translation, podocyte injury, and proteinuria, all reversed by VX-147. Together, these results establish APOL1-mediated Na+/K+ transport as the proximal driver of APOL1-mediated kidney disease.

Authors

Somenath Datta, Brett M. Antonio, Nathan H. Zahler, Jonathan W. Theile, Doug Krafte, Hengtao Zhang, Paul B. Rosenberg, Alec B. Chaves, Deborah M. Muoio, Guofang Zhang, Daniel Silas, Guojie Li, Karen Soldano, Sarah Nystrom, Davis Ferreira, Sara E. Miller, James R. Bain, Michael J. Muehlbauer, Olga Ilkayeva, Thomas C. Becker, Hans-Ewald Hohmeier, Christopher B. Newgard, Opeyemi A. Olabisi

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Figure 10

VX-147 rescues G1-induced podocyte injury and proteinuria in vivo.

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VX-147 rescues G1-induced podocyte injury and proteinuria in vivo. (A) E...
(A) Eight-week-old APOL1 G1 transgenic mice received 1 of 3 treatments: PBS injection (control), IFN-γ injection (on day 0), or IFN-γ injection on day 0 and VX-147 on days 0, 1, and 2 (n = 4 mice/treatment). (B) Representative electron micrographs from each of the 3 treatment groups. IFN-γ–treated APOL1 G1 mice developed focal podocyte foot process effacement (white arrows), microvillar transformation, and cytoplasmic shedding (Supplemental Figure 11). VX-147 rescued all of these histopathologic phenotypes. (C) IFN-γ–treated APOL1 G1 mice developed robust proteinuria by day 2, which was significantly attenuated by VX-147. (D) Measurement of APOL1 G1 expression in whole kidney lysate by qPCR shows that IFN-γ increased APOL1 expression and that VX-147 does not alter the expression level. (E) Serum creatine is unchanged, but (F) BUN is increased by IFN-γ treatment, an effect rescued by VX-147. (G) Measurement of NLRP3 by qPCR in whole kidney lysate shows increased NLRP3 mRNA transcript in IFN-γ–treated APOL1 G1 mice independent of VX-147. (H) IFN-γ–induced APOL1 G1 does not increase NLRP3 in primary podocytes. GAPDH was used as internal control for qPCR fold-change analysis (n = 3). All data are represented as mean ± SD. *P ≤ 0.05; **P ≤ 0.005, ordinary 1-way ANOVA with Tukey’s multiple-comparison test (C, D, G and H) and 2-tailed t test (E and F).