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The actin cytoskeleton of kidney podocytes is a direct target of the antiproteinuric effect of cyclosporine A

Nature Medicine volume 14, pages 931938 (2008) | Download Citation

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Abstract

The immunosuppressive action of the calcineurin inhibitor cyclosporine A (CsA) stems from the inhibition of nuclear factor of activated T cells (NFAT) signaling in T cells. CsA is also used for the treatment of proteinuric kidney diseases. As it stands, the antiproteinuric effect of CsA is attributed to its immunosuppressive action. Here we show that the beneficial effect of CsA on proteinuria is not dependent on NFAT inhibition in T cells, but rather results from the stabilization of the actin cytoskeleton in kidney podocytes. CsA blocks the calcineurin-mediated dephosphorylation of synaptopodin, a regulator of Rho GTPases in podocytes, thereby preserving the phosphorylation-dependent synaptopodin–14-3-3β interaction. Preservation of this interaction, in turn, protects synaptopodin from cathepsin L–mediated degradation. These results represent a new view of calcineurin signaling and shed further light on the treatment of proteinuric kidney diseases. Novel calcineurin substrates such as synaptopodin may provide promising starting points for antiproteinuric drugs that avoid the serious side effects of long-term CsA treatment.

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Acknowledgements

We thank C. Chiu and S. Ratner for excellent technical assistance and T. Reinheckel for the analysis of CatL cleavage sites. We thank the Mount Sinai School of Medicine Mouse Genetics Research Facility for performing pronuclear injections. We also thank J.B. Kopp (US National Institutes of Health) for providing the podocin-rtTA mice, H. Fu (Emory University) for yellow fluorescence protein–tagged difopein and E.N. Olson (The University of Texas Southwestern Medical Center at Dallas) for wild-type and constitutively active calcineurin cDNA constructs. Y.H.C. was supported by a research fellowship from the Albert Einstein College of Medicine, S.F. was supported by Karger Stiftung and J.D. was supported by the Deutsche Forschungsgemeinschaft. This work was supported by US National Institutes of Health grants DA18886, DK57683 and DK062472 and the George M. O'Brien Kidney Center grants DK064236 (to P.M.) and DK073495 (to J.R.).

Author information

Author notes

    • Yoon Hee Chang
    • , Stefan Franz
    •  & Jacqueline Delfgaauw

    Present addresses: Department of Medicine, Yale New Haven Hospital, 20 York Street, New Haven, Connecticut 06510, USA (Y.H.C.); Roche Pharma Switzerland, Schönmattstrasse 2, CH-4153 Reinach, Switzerland (S.F.); Development Science, Grünenthal, Ziegelstrasse, D-52078 Aachen, Germany (J.D.).

Affiliations

  1. Department of Medicine, University of Miami Miller School of Medicine, 1600 Northwest Tenth Avenue, Miami, Florida 33136, USA.

    • Christian Faul
    • , Mary Donnelly
    • , Sandra Merscher-Gomez
    • , Kirk N Campbell
    • , Jochen Reiser
    •  & Peter Mundel
  2. Department of Medicine, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, New York 10029, USA.

    • Christian Faul
    • , Mary Donnelly
    • , Sandra Merscher-Gomez
    • , Yoon Hee Chang
    • , Stefan Franz
    • , Jacqueline Delfgaauw
    • , Hoon Young Choi
    • , Kirk N Campbell
    • , Kwanghee Kim
    •  & Peter Mundel
  3. Department of Internal Medicine, Hsiao-Kang Municipal Hospital, Kaohsiung, Medical University, 482 Shan-ming Road, Kaohsiung, Taiwan.

    • Jer-Ming Chang
  4. Nephrology Division and Program in Glomerular Disease, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, 149 Thirteenth Street, Boston, Massachusetts 02129, USA.

    • Jochen Reiser

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Corresponding author

Correspondence to Peter Mundel.

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DOI

https://doi.org/10.1038/nm.1857

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