1. Autophagy markers LC3 and p62 accumulate in immune‐mediated necrotizing myopathy
- Author
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A. Amati, Tiziana Annese, Dario D'Abbicco, Domenico Ribatti, L. Serlenga, Maria Trojano, Francesco Girolamo, Marilina Tampoia, Florenzo Iannone, Daniela Virgintino, Anna Lia, and Margherita Giannini
- Subjects
Adult ,Male ,0301 basic medicine ,Pathology ,medicine.medical_specialty ,Physiology ,Biopsy ,030105 genetics & heredity ,Protein degradation ,Polymyositis ,Dermatomyositis ,Autoimmune Diseases ,Myositis, Inclusion Body ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,0302 clinical medicine ,Ubiquitin ,Physiology (medical) ,Autophagy ,medicine ,Humans ,Myocyte ,Muscle, Skeletal ,Aged ,Aged, 80 and over ,Myositis ,biology ,business.industry ,Middle Aged ,medicine.disease ,biology.protein ,Immunohistochemistry ,Female ,Creatine kinase ,Neurology (clinical) ,business ,030217 neurology & neurosurgery - Abstract
Introduction The molecular mechanism of immune-mediated necrotizing myopathy (IMNM) remains unknown. Autophagy impairment, described in autoimmune diseases, is a key process in myofiber protein degradation flux and muscle integrity and has not been studied in IMNM. Methods Muscle biopsies from patients with IMNM (n = 40), dermatomyositis (DM; 24), polymyositis (PM; 8), polymyositis with mitochondrial pathology (4), sporadic inclusion body myositis (8), and controls (6) were compared by immunohistochemistry. Results The proportions of myofibers containing autophagy markers LC3b and p62 were higher in IMNM than in DM or PM and correlated with creatine kinase levels. In IMNM, compartmentalized LC3b puncta were located in regenerating and degenerating myofibers surrounded by major histocompatibility complex type II+ inflammatory cells. Several IMNM myofibers accumulated ubiquitin and misfolded protein. Discussion The detection of LC3b+ or p62+ myofibers could be used in differentiating IMNM from PM. The identification of autophagy-modifying molecules potentially could improve patients' outcomes. Muscle Nerve, 2019.
- Published
- 2019