Productive infection of human skeletal muscle cells by pandemic and seasonal influenza A(H1N1) viruses

PLoS One. 2013 Nov 5;8(11):e79628. doi: 10.1371/journal.pone.0079628. eCollection 2013.

Abstract

Besides the classical respiratory and systemic symptoms, unusual complications of influenza A infection in humans involve the skeletal muscles. Numerous cases of acute myopathy and/or rhabdomyolysis have been reported, particularly following the outbreak of pandemic influenza A(H1N1) in 2009. The pathogenesis of these influenza-associated myopathies (IAM) remains unkown, although the direct infection of muscle cells is suspected. Here, we studied the susceptibility of cultured human primary muscle cells to a 2009 pandemic and a 2008 seasonal influenza A(H1N1) isolate. Using cells from different donors, we found that differentiated muscle cells (i. e. myotubes) were highly susceptible to infection by both influenza A(H1N1) isolates, whereas undifferentiated cells (i. e. myoblasts) were partially resistant. The receptors for influenza viruses, α2-6 and α2-3 linked sialic acids, were detected on the surface of myotubes and myoblasts. Time line of viral nucleoprotein (NP) expression and nuclear export showed that the first steps of the viral replication cycle could take place in muscle cells. Infected myotubes and myoblasts exhibited budding virions and nuclear inclusions as observed by transmission electron microscopy and correlative light and electron microscopy. Myotubes, but not myoblasts, yielded infectious virus progeny that could further infect naive muscle cells after proteolytic treatment. Infection led to a cytopathic effect with the lysis of muscle cells, as characterized by the release of lactate dehydrogenase. The secretion of proinflammatory cytokines by muscle cells was not affected following infection. Our results are compatible with the hypothesis of a direct muscle infection causing rhabdomyolysis in IAM patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Death
  • Cell Differentiation
  • Cell Proliferation
  • Humans
  • Influenza A Virus, H1N1 Subtype / physiology*
  • Muscle Fibers, Skeletal / cytology
  • Muscle Fibers, Skeletal / metabolism
  • Muscle Fibers, Skeletal / virology
  • Muscle, Skeletal / cytology*
  • Muscle, Skeletal / virology*
  • Myoblasts / cytology
  • Myoblasts / virology
  • Pandemics*
  • Receptors, Cell Surface / metabolism
  • Seasons*
  • Virus Replication

Substances

  • Receptors, Cell Surface

Grant support

Funding for this work was provided by the Institut Pasteur, the Centre National de la Recherche Scientifique (CNRS) and Université Paris VII. MD was a recipient of a fellowship from the french ministry of education and research. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.