NEB mutations disrupt the super-relaxed state of myosin and remodel the muscle metabolic proteome in nemaline myopathy

Natasha Ranu, Jenni Laitila, Hannah F. Dugdale, Jennifer Mariano, Justin S. Kolb, Carina Wallgren-Pettersson, Nanna Witting, John Vissing, Juan Jesus Vilchez, Chiara Fiorillo, Edmar Zanoteli, Mari Auranen, Manu Jokela, Giorgio Tasca, Kristl G. Claeys, Nicol C. Voermans, Johanna Palmio, Sanna Huovinen, Maurizio Moggio, Thomas Nyegaard BeckAikaterini Kontrogianni-Konstantopoulos, Henk Granzier, Julien Ochala

Research output: Contribution to journalArticlepeer-review

Abstract

Nemaline myopathy (NM) is one of the most common non-dystrophic genetic muscle disorders. NM is often associated with mutations in the NEB gene. Even though the exact NEB-NM pathophysiological mechanisms remain unclear, histological analyses of patients’ muscle biopsies often reveal unexplained accumulation of glycogen and abnormally shaped mitochondria. Hence, the aim of the present study was to define the exact molecular and cellular cascade of events that would lead to potential changes in muscle energetics in NEB-NM. For that, we applied a wide range of biophysical and cell biology assays on skeletal muscle fibres from NM patients as well as untargeted proteomics analyses on isolated myofibres from a muscle-specific nebulin‐deficient mouse model. Unexpectedly, we found that the myosin stabilizing conformational state, known as super-relaxed state, was significantly impaired, inducing an increase in the energy (ATP) consumption of resting muscle fibres from NEB-NM patients when compared with controls or with other forms of genetic/rare, acquired NM. This destabilization of the myosin super-relaxed state had dynamic consequences as we observed a remodeling of the metabolic proteome in muscle fibres from nebulin‐deficient mice. Altogether, our findings explain some of the hitherto obscure hallmarks of NM, including the appearance of abnormal energy proteins and suggest potential beneficial effects of drugs targeting myosin activity/conformations for NEB-NM.

Original languageEnglish (US)
Article number185
JournalActa neuropathologica communications
Volume10
Issue number1
DOIs
StatePublished - Dec 2022

Keywords

  • Metabolism
  • Myosin
  • Nebulin
  • Nemaline myopathy
  • Skeletal muscle

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Clinical Neurology
  • Cellular and Molecular Neuroscience

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