Volume 11, Issue 6 pp. 1036-1045
Original Article

Age-related loss of nitric oxide synthase in skeletal muscle causes reductions in calpain S-nitrosylation that increase myofibril degradation and sarcopenia

Giuseppina Samengo

Giuseppina Samengo

Department of Integrative Biology and Physiology, University of California, Los Angeles, CA, USA

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Anna Avik

Anna Avik

Department of Integrative Biology and Physiology, University of California, Los Angeles, CA, USA

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Brian Fedor

Brian Fedor

Department of Integrative Biology and Physiology, University of California, Los Angeles, CA, USA

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Daniel Whittaker

Daniel Whittaker

Department of Integrative Biology and Physiology, University of California, Los Angeles, CA, USA

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Kyu H. Myung

Kyu H. Myung

Animal Science Department, Chonnam National University, Gwangju, Korea

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Michelle Wehling-Henricks

Michelle Wehling-Henricks

Department of Integrative Biology and Physiology, University of California, Los Angeles, CA, USA

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James G. Tidball

Corresponding Author

James G. Tidball

Department of Integrative Biology and Physiology, University of California, Los Angeles, CA, USA

Molecular, Cellular & Integrative Physiology Program, University of California, Los Angeles, CA, USA

Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA, USA

Correspondence:

James G. Tidball, Molecular, Cellular & Integrative Physiology Program

University of California, Los Angeles, CA 90095-1606, USA. Tel.: +1 310 206 3395; fax: +1 310 825 8489; e-mail: [email protected]

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First published: 05 September 2012
Citations: 78

Summary

Sarcopenia, the age-related loss of muscle mass, is a highly-debilitating consequence of aging. In this investigation, we show sarcopenia is greatly reduced by muscle-specific overexpression of calpastatin, the endogenous inhibitor of calcium-dependent proteases (calpains). Further, we show that calpain cleavage of specific structural and regulatory proteins in myofibrils is prevented by covalent modification of calpain by nitric oxide (NO) through S-nitrosylation. We find that calpain in adult, non-sarcopenic muscles is S-nitrosylated but that aging leads to loss of S-nitrosylation, suggesting that reduced S-nitrosylation during aging leads to increased calpain-mediated proteolysis of myofibrils. Further, our data show that muscle aging is accompanied by loss of neuronal nitric oxide synthase (nNOS), the primary source of muscle NO, and that expression of a muscle-specific nNOS transgene restores calpain S-nitrosylation in aging muscle and prevents sarcopenia. Together, the findings show that in vivo reduction of calpain S-nitrosylation in muscle may be an important component of sarcopenia, indicating that modulation of NO can provide a therapeutic strategy to slow muscle loss during old age.

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