Neuromuscular electrical stimulation promotes development in mice of mature human muscle from immortalized human myoblasts.

Guido Stadler,Joseph A. Roche,Amber L. Mueller,Robert J. Bloch,Paraskevi Sakellariou,Woodring E. Wright,Andrea O’Neill

doi:10.1186/s13395-016-0078-6

Abstract

BackgroundStudies of the pathogenic mechanisms underlying human myopathies and muscular dystrophies often require animal models, but models of some human diseases are not yet available. Methods to promote the engraftment and development of myogenic cells from individuals with such diseases in mice would accelerate such studies and also provide a useful tool for testing therapeutics. Here, we investigate the ability of immortalized human myogenic precursor cells (hMPCs) to form mature human myofibers following implantation into the hindlimbs of non-obese diabetic-Rag1 null IL2rγ null (NOD-Rag)-immunodeficient mice.ResultsWe report that hindlimbs of NOD-Rag mice that are X-irradiated, treated with cardiotoxin, and then injected with immortalized control hMPCs or hMPCs from an individual with facioscapulohumeral muscular dystrophy (FSHD) develop mature human myofibers. Furthermore, intermittent neuromuscular electrical stimulation (iNMES) of the peroneal nerve of the engrafted limb enhances the development of mature fibers in the grafts formed by both immortal cell lines. With control cells, iNMES increases the number and size of the human myofibers that form and promotes closer fiber-to-fiber packing. The human myofibers in the graft are innervated, fully differentiated, and minimally contaminated with murine myonuclei.ConclusionsOur results indicate that control and FSHD human myofibers can form in mice engrafted with hMPCs and that iNMES enhances engraftment and subsequent development of mature human muscle.

Highlights

Studies of the pathogenic mechanisms underlying human myopathies and muscular dystrophies often require animal models, but models of some human diseases are not yet available
These grafts are formed from muscle precursor cells in a compartment that is essentially devoid of murine muscle, in contrast to grafts of bundles of intact muscle fibers sewn into pre-existing murine muscle, as recently described [7]
We have not yet studied the muscles formed by the grafts in isolation, our preliminary observations indicate that they do contract in response to electrical stimulation

Summary

Introduction

Studies of the pathogenic mechanisms underlying human myopathies and muscular dystrophies often require animal models, but models of some human diseases are not yet available. Methods to promote the engraftment and development of myogenic cells from individuals with such diseases in mice would accelerate such studies and provide a useful tool for testing therapeutics. Developing murine models to study these diseases is essential in understanding the mechanisms of pathogenesis and in testing potential therapies. Sakellariou et al Skeletal Muscle (2016) 6:4 of these grafts survive and reform mature muscle tissue that is largely human in origin, they can contain significant numbers of murine myonuclei. The myofibers in these grafts can be innervated by motor neurons and supplied by capillaries that are murine in origin, and they contract in response to electrical stimulation. The mice carrying these human grafts provide potentially excellent models, they would be difficult to generate in the numbers needed for therapeutic testing

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