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Activation of fast skeletal muscle troponin as a potential therapeutic approach for treating neuromuscular diseases

Abstract

Limited neural input results in muscle weakness in neuromuscular disease because of a reduction in the density of muscle innervation, the rate of neuromuscular junction activation or the efficiency of synaptic transmission1. We developed a small-molecule fast-skeletal–troponin activator, CK-2017357, as a means to increase muscle strength by amplifying the response of muscle when neural input is otherwise diminished secondary to neuromuscular disease. Binding selectively to the fast-skeletal–troponin complex, CK-2017357 slows the rate of calcium release from troponin C and sensitizes muscle to calcium. As a consequence, the force-calcium relationship of muscle fibers shifts leftwards, as does the force-frequency relationship of a nerve-muscle pair, so that CK-2017357 increases the production of muscle force in situ at sub-maximal nerve stimulation rates. Notably, we show that sensitization of the fast-skeletal–troponin complex to calcium improves muscle force and grip strength immediately after administration of single doses of CK-2017357 in a model of the neuromuscular disease myasthenia gravis. Troponin activation may provide a new therapeutic approach to improve physical activity in diseases where neuromuscular function is compromised.

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Figure 1: CK-2017357 is a selective calcium sensitizer of the fast-skeletal–troponin complex.
Figure 2: CK-2017357 binds to the skeletal-troponin complex and slows calcium release.
Figure 3: CK-2017357 shifts the plot of the force-calcium relationship in fast skeletal muscle leftwards and amplifies the response of muscle to nervous input.
Figure 4: CK-2017357 improves muscle and physical function in a model of neuromuscular disease.

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References

  1. Research Group in Neuromuscular Diseases. Classification of the neuromuscular disorders. Lancet 291, 1020–1021 (1968).

  2. Pollard, T. & Earnshaw, W. Cell Biology (Saunders/Elsevier, Philadelphia, 2008).

  3. Freund, H.J. Motor unit and muscle activity in voluntary motor control. Physiol. Rev. 63, 387–436 (1983).

    Article  CAS  PubMed  Google Scholar 

  4. Jasmin, B.J. & Gardiner, P.F. Patterns of EMG activity of rat plantaris muscle during swimming and other locomotor activities. J. Appl. Physiol. 63, 713–718 (1987).

    Article  CAS  PubMed  Google Scholar 

  5. Sharma, K.R. & Miller, R.G. Electrical and mechanical properties of skeletal muscle underlying increased fatigue in patients with amyotrophic lateral sclerosis. Muscle Nerve 19, 1391–1400 (1996).

    Article  CAS  PubMed  Google Scholar 

  6. Kent-Braun, J.A. & Miller, R.G. Central fatigue during isometric exercise in amyotrophic lateral sclerosis. Muscle Nerve 23, 909–914 (2000).

    Article  CAS  PubMed  Google Scholar 

  7. Patzkó, A. & Shy, M.E. Update on Charcot-Marie-Tooth disease. Curr. Neurol. Neurosci. Rep. 11, 78–88 (2011).

    Article  PubMed  PubMed Central  Google Scholar 

  8. Monani, U.R. Spinal muscular atrophy: a deficiency in a ubiquitous protein; a motor neuron-specific disease. Neuron 48, 885–896 (2005).

    Article  CAS  PubMed  Google Scholar 

  9. Drachman, D.B. Myasthenia gravis. N. Engl. J. Med. 330, 1797–1810 (1994).

    Article  CAS  PubMed  Google Scholar 

  10. Conti-Fine, B.M., Milani, M. & Kaminski, H.J. Myasthenia gravis: past, present, and future. J. Clin. Invest. 116, 2843–2854 (2006).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  11. Solaro, R.J., Pang, D.C. & Briggs, F.N. The purification of cardiac myofibrils with Triton X-100. Biochim. Biophys. Acta 245, 259–262 (1971).

    Article  CAS  PubMed  Google Scholar 

  12. Young, O.A. & Davey, C.L. Electrophoretic analysis of proteins from single bovine muscle fibres. Biochem. J. 195, 317–327 (1981).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  13. Herrmann, C., Sleep, J., Chaussepied, P., Travers, F. & Barman, T. A structural and kinetic study on myofibrils prevented from shortening by chemical cross-linking. Biochemistry 32, 7255–7263 (1993).

    Article  CAS  PubMed  Google Scholar 

  14. Bloemink, M.J., Adamek, N., Reggiani, C. & Geeves, M.A. Kinetic analysis of the slow skeletal myosin MHC-1 isoform from bovine masseter muscle. J. Mol. Biol. 373, 1184–1197 (2007).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  15. Malik, F.I. et al. Cardiac myosin activation: a potential therapeutic approach for systolic heart failure. Science 331, 1439–1443 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  16. Rosenfeld, S.S. & Taylor, E.W. Kinetic studies of calcium and magnesium binding to troponin C. J. Biol. Chem. 260, 242–251 (1985).

    CAS  PubMed  Google Scholar 

  17. Poole, K.J. et al. A comparison of muscle thin filament models obtained from electron microscopy reconstructions and low-angle X-ray fibre diagrams from non-overlap muscle. J. Struct. Biol. 155, 273–284 (2006).

    Article  CAS  PubMed  Google Scholar 

  18. Brooks, S.V. & Faulkner, J.A. Contraction-induced injury: recovery of skeletal muscles in young and old mice. Am. J. Physiol. 258, C436–C442 (1990).

    Article  CAS  PubMed  Google Scholar 

  19. Lindstrom, J.M., Engel, A.G., Seybold, M.E., Lennon, V.A. & Lambert, E.H. Pathological mechanisms in experimental autoimmune myasthenia gravis. II. Passive transfer of experimental autoimmune myasthenia gravis in rats with anti-acetylcholine receptor antibodies. J. Exp. Med. 144, 739–753 (1976).

    Article  CAS  PubMed  Google Scholar 

  20. Jiménez-Moreno, R., Wang, Z.M., Gerring, R.C. & Delbono, O. Sarcoplasmic reticulum Ca2+ release declines in muscle fibers from aging mice. Biophys. J. 94, 3178–3188 (2008).

    Article  PubMed  PubMed Central  Google Scholar 

  21. Erim, Z., Beg, M.F., Burke, D.T. & de Luca, C.J. Effects of aging on motor-unit control properties. J. Neurophysiol. 82, 2081–2091 (1999).

    Article  CAS  PubMed  Google Scholar 

  22. Ling, S.M., Conwit, R.A., Ferrucci, L. & Metter, E.J. Age-associated changes in motor unit physiology: observations from the Baltimore Longitudinal Study of Aging. Arch. Phys. Med. Rehabil. 90, 1237–1240 (2009).

    Article  PubMed  PubMed Central  Google Scholar 

  23. Talmadge, R.J. & Roy, R.R. Electrophoretic separation of rat skeletal muscle myosin heavy-chain isoforms. J. Appl. Physiol. 75, 2337–2340 (1993).

    Article  CAS  PubMed  Google Scholar 

  24. Margossian, S.S. & Lowey, S. Preparation of myosin and its subfragments from rabbit skeletal muscle. Methods Enzymol. 85 Pt B, 55–71 (1982).

    Article  CAS  PubMed  Google Scholar 

  25. Pardee, J.D. & Spudich, J.A. Purification of muscle actin. Methods Enzymol. 85 Pt B, 164–181 (1982).

    Article  CAS  PubMed  Google Scholar 

  26. Potter, J.D. Preparation of troponin and its subunits. Methods Enzymol. 85 Pt B, 241–263 (1982).

    Article  CAS  PubMed  Google Scholar 

  27. Smillie, L.B. Preparation and identification of α- and β-tropomyosins. Methods Enzymol. 85 Pt B, 234–241 (1982).

    Article  CAS  PubMed  Google Scholar 

  28. Ebashi, S., Ebashi, F. & Kodama, A. Troponin as the Ca++-receptive protein in the contractile system. J. Biochem. 62, 137–138 (1967).

    Article  CAS  PubMed  Google Scholar 

  29. Spudich, J.A. & Watt, S. The regulation of rabbit skeletal muscle contraction. I. Biochemical studies of the interaction of the tropomyosin-troponin complex with actin and the proteolytic fragments of myosin. J. Biol. Chem. 246, 4866–4871 (1971).

    CAS  PubMed  Google Scholar 

  30. Claflin, D.R. et al. Effects of high- and low-velocity resistance training on the contractile properties of skeletal muscle fibers from young and older humans. J. Appl. Physiol. 111, 1021–1030 (2011).

    Article  PubMed  PubMed Central  Google Scholar 

  31. De La Cruz, E.M. & Ostap, E.M. Kinetic and equilibrium analysis of the myosin ATPase. Methods Enzymol. 455, 157–192 (2009).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  32. Rosenfeld, S.S. & Taylor, E.W. Kinetic studies of calcium binding to regulatory complexes from skeletal muscle. J. Biol. Chem. 260, 252–261 (1985).

    CAS  PubMed  Google Scholar 

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Acknowledgements

The project described was supported by Cytokinetics, Inc. and by award number 1RC3NS070670-01 (F.I.M.) from the National Institute of Neurological Disorders and Stroke. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute of Neurological Disorders and Stroke or the US National Institutes of Health.

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All authors contributed extensively to the work presented in this paper.

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Correspondence to Fady I Malik.

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A.J.R., J.J.H., A.C.H., A.R.M., R.K., L.D., G.G., K.H.L., D.M., W.F.B., M.M.C., D.C., S.E.C., M.G., R.H., Z.J., P.-P.L., H.R., K.G.S., J.S., V.V., D.J.M., B.P.M. and F.I.M. are past or present employees of Cytokinetics, Inc. and own stock or stock options in Cytokinetics, Inc. D.L.A. and D.R.C. received research support from Cytokinetics, Inc.

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Russell, A., Hartman, J., Hinken, A. et al. Activation of fast skeletal muscle troponin as a potential therapeutic approach for treating neuromuscular diseases. Nat Med 18, 452–455 (2012). https://doi.org/10.1038/nm.2618

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