Sarcolemmal neuronal nitric oxide synthase defect in limb-girdle muscular dystrophy: An adverse modulating factor in the disease course?

Marina Fanin, Elisabetta Tasca, Anna Chiara Nascimbeni, Corrado Angelini

Research output: Contribution to journalArticle

Abstract

Reduction of neuronal nitric oxide synthase (nNOS) has been associated with the pathogenesis and clinical expression of inherited myopathies. To determine whether a defect in nNOS might be an adverse modulating factor in the course of limb-girdle muscular dystrophy, we investigated cytosolic and sarcolemmal nNOS expression in muscle biopsies from 32 patients with 7 forms of limb-girdle muscular dystrophy. Primary calpainopathy, dysferlinopathy, and caveolinopathy biopsies showed normal levels of cytosolic nNOS and preserved sarcolemmal nNOS immunoreactivity. By contrast, the cytosolic nNOS levels in sarcoglycanopathy muscles were variably reduced. Sarcolemmal nNOS immunoreactivity varied from absent to reduced, depending on the integrity of the sarcoglycan complex. In muscles with loss of the entire sarcoglycan complex, sarcolemmal nNOS was absent; it otherwise depended on the specific sarcoglycan gene and type of mutation. The integrity of the entire sarcoglycan complex is, therefore, essential for the stabilization of nNOS to the sarcolemma. Absence of sarcolemmal nNOS in sarcoglycanopathy muscle was always associated with severe muscular dystrophy and sometimes with dilated cardiomyopathy, supporting the hypothesis that nNOS defect might contribute to skeletal and cardiac muscle disease progression. These results emphasize the value of nNOS immunohistochemical analysis in limb-girdle muscular dystrophy and provide additional insights for future therapeutic interventions in these disorders.

Original languageEnglish
Pages (from-to)383-390
Number of pages8
JournalJournal of Neuropathology and Experimental Neurology
Volume68
Issue number4
DOIs
Publication statusPublished - Apr 2009

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Keywords

  • Limb-girdle muscular dystrophy
  • Nitric oxide synthase
  • NNOS
  • Sarcoglycan

ASJC Scopus subject areas

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

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