Triggering typical nemaline myopathy with compound heterozygous nebulin mutations reveals myofilament structural changes as pathomechanism

Johan Lindqvist, Weikang Ma, Frank Li, Yaeren Hernandez, Justin Kolb, Balazs Kiss, Paola Tonino, Robbert van der Pijl, Esmat Karimi, Henry Gong, Josh Strom, Zaynab Hourani, John E. Smith, Coen Ottenheijm, Thomas Irving, Henk Granzier

Research output: Contribution to journalArticle

Abstract

Nebulin is a giant protein that winds around the actin filaments in the skeletal muscle sarcomere. Compound-heterozygous mutations in the nebulin gene (NEB) cause typical nemaline myopathy (NM), a muscle disorder characterized by muscle weakness with limited treatment options. We created a mouse model with a missense mutation p.Ser6366Ile and a deletion of NEB exon 55, the Compound-Het model that resembles typical NM. We show that Compound-Het mice are growth-retarded and have muscle weakness. Muscles have a reduced myofibrillar fractional-area and sarcomeres are disorganized, contain rod bodies, and have longer thin filaments. In contrast to nebulin-based severe NM where haplo-insufficiency is the disease driver, Compound-Het mice express normal amounts of nebulin. X-ray diffraction revealed that the actin filament is twisted with a larger radius, that tropomyosin and troponin behavior is altered, and that the myofilament spacing is increased. The unique disease mechanism of nebulin-based typical NM reveals novel therapeutic targets.

Original languageEnglish (US)
Article number2699
JournalNature communications
Volume11
Issue number1
DOIs
StatePublished - Dec 1 2020

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

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    Lindqvist, J., Ma, W., Li, F., Hernandez, Y., Kolb, J., Kiss, B., Tonino, P., van der Pijl, R., Karimi, E., Gong, H., Strom, J., Hourani, Z., Smith, J. E., Ottenheijm, C., Irving, T., & Granzier, H. (2020). Triggering typical nemaline myopathy with compound heterozygous nebulin mutations reveals myofilament structural changes as pathomechanism. Nature communications, 11(1), [2699]. https://doi.org/10.1038/s41467-020-16526-9