Disrupted apolipoprotein L1-miR193a axis dedifferentiates podocytes through autophagy blockade in an APOL1 risk milieu

Vinod Kumar, Kamesh Ayasolla, Alok Jha, Abheepsa Mishra, Himanshu Vashistha, Xiqian Lan, Maleeha Qayyum, Sushma Chinnapaka, Richa Purohit, Joanna Mikulak, Moin A. Saleem, Ashwani Malhotra, Karl Skorecki, Pravin C. Singhal

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

We hypothesized that a functional apolipoprotein LI (APOL1)-miR193a axis (inverse relationship) preserves, but disruption alters, the podocyte molecular phenotype through the modulation of autophagy flux. Podocyte-expressing APOL1G0 (G0-podocytes) showed downregulation but podocyteexpressing APOL1G1 (G1-podocytes) and APOL1G2 (G2-podocytes) displayed enhanced miR193a expression. G0-, G1-, and G2- podocytes showed enhanced expression of light chain (LC) 3-II and beclin-1, but a disparate expression of p62 (low in wild-type but high in risk alleles). G0-podocytes showed enhanced, whereas G1- and G2-podocytes displayed decreased, phosphorylation of Unc-51-like autophagy-activating kinase (ULK)1 and class III phosphatidylinositol 3-kinase (PI3KC3). Podocytes overexpressing miR193a (miR193a-podocytes), G1, and G2 showed decreased transcription of PIK3R3 (PI3KC3=s regulatory unit). Since 3-methyladenine (3-MA) enhanced miR193a expression but inhibited PIK3R3 transcription, it appears that 3-MA inhibits autophagy and induces podocyte dedifferentiation via miR193a generation. miR193a-, G1-, and G2-podocytes also showed decreased phosphorylation of mammalian target of rapamycin (mTOR) that could repress lysosome reformation. G1- and G2-podocytes showed enhanced expression of run domain beclin-1- interacting and cysteine-rich domain-containing protein (Rubicon); however, its silencing prevented their dedifferentiation. Docking, protein-protein interaction, and immunoprecipitation studies with antiautophagy- related gene (ATG)14L, anti-UV radiation resistance associated gene (UVRAG), or Rubicon antibodies suggested the formation of ATG14L complex I and UVRAG complex II in G0-podocytes and the formation of Rubicon complex III in G1- and G2-podocytes. These findings suggest that the APOL1 risk alleles favor podocyte dedifferentiation through blockade of multiple autophagy pathways.

Original languageEnglish
Pages (from-to)C209-C225
JournalAmerican Journal of Physiology - Cell Physiology
Volume317
Issue number2
DOIs
StatePublished - 1 Aug 2019
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2019 the American Physiological Society.

Funding

This work was supported by National Institute of Diabetes and Digestive and Kidney Diseases Grants RO1 DK-098074 and RO1 DK-118017 to P. C. Singhal and by grants to K. Skorecki from the Israel Science Foundation (ISF 182/15) and Rambam Medical Center, Kaylie Kidney Health Center of Excellence, and the Beutler Foundation for Genomic Medicine Research.

FundersFunder number
Beutler Foundation
National Institute of Diabetes and Digestive and Kidney DiseasesR01DK118017, RO1 DK-098074
Israel Science FoundationISF 182/15

    Keywords

    • APOL1
    • Autophagy
    • Dedifferentiation of podocytes
    • MiR193a
    • Podocytes

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