LARGE expression in different types of muscular dystrophies other than dystroglycanopathy


Balci-Hayta B., TALİM B., KALE G., Dincer P.

BMC NEUROLOGY, vol.18, 2018 (Peer-Reviewed Journal) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 18
  • Publication Date: 2018
  • Doi Number: 10.1186/s12883-018-1207-0
  • Journal Name: BMC NEUROLOGY
  • Journal Indexes: Science Citation Index Expanded, Scopus

Abstract

BackgroundAlpha-dystroglycan (DG) is an extracellular peripheral glycoprotein that acts as a receptor for both extracellular matrix proteins containing laminin globular domains and certain arenaviruses. An important enzyme, known as Like-acetylglucosaminyltransferase (LARGE), has been shown to transfer repeating units of -glucuronic acid-1,3-xylose-1,3- (matriglycan) to DG that is required for functional receptor as an extracellular matrix protein scaffold. The reduction in the amount of LARGE-dependent matriglycan result in heterogeneous forms of dystroglycanopathy that is associated with hypoglycosylation of DG and a consequent lack of ligand-binding activity. Our aim was to investigate whether LARGE expression showed correlation with glycosylation of DG and histopathological parameters in different types of muscular dystrophies, except for dystroglycanopathies.MethodsThe expression level of LARGE and glycosylation status of DG were examined in skeletal muscle biopsies from 26 patients with various forms of muscular dystrophy [Duchenne muscular dystrophy (DMD), Becker muscular dystrophy (BMD), sarcoglycanopathy, dysferlinopathy, calpainopathy, and merosin and collagen VI deficient congenital muscular dystrophies (CMDs)] and correlation of results with different histopathological features was investigated.ResultsDespite the fact that these diseases are not caused by defects of glycosyltransferases, decreased expression of LARGE was detected in many patient samples, partly correlating with the type of muscular dystrophy. Although immunolabelling of fully glycosylated DG with VIA4-1 was reduced in dystrophinopathy patients, no significant relationship between reduction of LARGE expression and DG hypoglycosylation was detected. Also, Merosin deficient CMD patients showed normal immunostaining with DG despite severe reduction of LARGE expression.ConclusionsOur data shows that it is not always possible to correlate LARGE expression and DG glycosylation in different types of muscular dystrophies and suggests that there might be differences in DG processing by LARGE which could be regulated under different pathological conditions.