rAAV-related therapy fully rescues myonuclear and myofilament function in X-linked myotubular myopathy

Acta Neuropathologica Communications

Yotam Levy¹  Jacob A. Ross²  Julien Ochala³  Edmar Zanoteli⁴  David L. Mack⁵  Michael W. Lawlor⁶  Dawn A. Lowe⁷  Jocelyn Laporte⁸  Hichem Tasfaout⁸  Belinda S. Cowling⁸  Jennifer Morgan⁹  Norma B. Romero^1,10  Heinz Jungbluth^1,11 

[1] Centre of Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, Faculty of Life Sciences & Medicine, King’s College London, London, UK;Centre of Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, Faculty of Life Sciences & Medicine, King’s College London, London, UK;British Heart Foundation Centre of Excellence, School of Cardiovascular Sciences, Faculty of Life Sciences & Medicine, King’s College London, London, UK;Centre of Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, Faculty of Life Sciences & Medicine, King’s College London, London, UK;Randall Centre for Cell and Molecular Biophysics, School of Basic & Medical Biosciences, Faculty of Life Sciences & Medicine, Guy’s Campus, King’s College London, London, UK;Department of Biomedical Sciences, University of Copenhagen, Copenhagen N, Denmark;Department of Neurology, Faculdade de Medicina (FMUSP), Universidade de São Paulo, São Paulo, Brazil;Department of Rehabilitation Medicine, University of Washington, Seattle, WA, USA;Institute for Stem Cell and Regenerative Medicine, School of Medicine, University of Washington, Seattle, USA;Division of Paediatric Pathology, Department of Pathology and Laboratory Medicine and Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, WI, USA;Division of Rehabilitation Science and Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA;Institut de Génétique Et de Biologie Moléculaire Et Cellulaire (IGBMC), INSERM U1258, CNRS UMR7104, Université de Strasbourg, Illkirch, France;National Institute for Health Research, Great Ormond Street Institute of Child Health Biomedical Research Centre, University College London, 30 Guilford Street, London, UK;Dubowitz Neuromuscular Centre, University College London, Great Ormond Street Institute of Child Health, 30 Guilford Street, London, UK;Neuromuscular Morphology Unit, Myology Institute, Sorbonne Université, Centre de Référence de Pathologie Neuromusculaire Nord/Est/Ile-de-France (APHP), GH Pitié-Salpêtrière, Paris, France;Randall Centre for Cell and Molecular Biophysics, School of Basic & Medical Biosciences, Faculty of Life Sciences & Medicine, Guy’s Campus, King’s College London, London, UK;Department of Paediatric Neurology, Neuromuscular Service, Evelina’s Children Hospital, Guy’s and St Thomas’ Hospital National Health Service Foundation Trust, London, UK;Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK;

关键词: Skeletal muscle;    Congenital myopathy;    Myotubularin;    Myonuclear domain;    Myofilament;    Force production;   

DOI  :  10.1186/s40478-020-01048-8

来源: Springer

【 摘 要 】

X-linked myotubular myopathy (XLMTM) is a life-threatening skeletal muscle disease caused by mutations in the MTM1 gene. XLMTM fibres display a population of nuclei mispositioned in the centre. In the present study, we aimed to explore whether positioning and overall distribution of nuclei affects cellular organization and contractile function, thereby contributing to muscle weakness in this disease. We also assessed whether gene therapy alters nuclear arrangement and function. We used tissue from human patients and animal models, including XLMTM dogs that had received increasing doses of recombinant AAV8 vector restoring MTM1 expression (rAAV8-cMTM1). We then used single isolated muscle fibres to analyze nuclear organization and contractile function. In addition to the expected mislocalization of nuclei in the centre of muscle fibres, a novel form of nuclear mispositioning was observed: irregular spacing between those located at the fibre periphery, and an overall increased number of nuclei, leading to dramatically smaller and inconsistent myonuclear domains. Nuclear mislocalization was associated with decreases in global nuclear synthetic activity, contractile protein content and intrinsic myofilament force production. A contractile deficit originating at the myofilaments, rather than mechanical interference by centrally positioned nuclei, was supported by experiments in regenerated mouse muscle. Systemic administration of rAAV8-cMTM1 at doses higher than 2.5 × 1013 vg kg−1 allowed a full rescue of all these cellular defects in XLMTM dogs. Altogether, these findings identify previously unrecognized pathological mechanisms in human and animal XLMTM, associated with myonuclear defects and contractile filament function. These defects can be reversed by gene therapy restoring MTM1 expression in dogs with XLMTM.

【 授权许可】

CC BY