title: Improvement of calcium handling and changes in calcium-release properties after mini- or full-length dystrophin forced expression in cultured skeletal myotubes.
abstract: Dystrophin is a cytoskeletal protein normally expressed underneath the sarcolemma of muscle fibers. The lack of dystrophin in Duchenne muscular Dystrophy (DMD) muscles results in fiber necrosis, which was proposed to be mediated by chronic calcium mishandling. The extensive comparison of dystrophic cells from human or mdx mice with normal muscles have suggested that the lack of dystrophin may alter the resting calcium permeability and steady-state levels of calcium, but this latter observation remains controversial. It is also not clear, whether calcium mishandling is resulting from the dystrophic process or if dystrophin can directly regulate calcium handling in muscle cells. This prompted us to determine if transfection of full-length dystrophin or Becker Muscular Dystrophy (BMD) minidystrophin, a candidate for viral-mediated gene therapy, could change calcium handling properties. We took advantage of specific properties of Sol8 cell line showing the absence of dystrophin expression together with a drastic calcium mishandling. Here, we show that full-length dystrophin allowed the recovery of a low resting intracellular-free calcium concentration together with lower calcium transients. We also show for the first time that stable expression of minidystrophin was able to restore normal calcium handling in Sol8 myotubes through a better control of steady-state levels, calcium transients, and subcellular calcium events. It suggests that dystrophin could play a regulatory role on calcium homeostasis apparatus and that functional links exist between calcium signaling and cytoskeleton.
authors.affiliation: Institut de Physiologie et Biologie Cellulaire, UMR CNRS/Université de Poitiers 6187, Pôle Biologie Santé, 86022 Poitiers cedex, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Marchand
authors.forename: Bruno
authors.initials: B
authors.lastname: Constantin
authors.forename: Haouaria
authors.initials: H
authors.lastname: Balghi
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Claudepierre
authors.forename: Anne
authors.initials: A
authors.lastname: Cantereau
authors.forename: Christophe
authors.initials: C
authors.lastname: Magaud
authors.forename: Aklesso
authors.initials: A
authors.lastname: Mouzou
authors.forename: Guy
authors.initials: G
authors.lastname: Raymond
authors.forename: Serge
authors.initials: S
authors.lastname: Braun
authors.forename: Christian
authors.initials: C
authors.lastname: Cognard
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002232:Carbocyanines; D002478:Cells, Cultured; D016189:Dystrophin / Q000235:genetics / Q000378:metabolism*; D005456:Fluorescent Dyes; D049452:Green Fluorescent Proteins; D006706:Homeostasis; D007150:Immunohistochemistry; D008164:Luminescent Proteins; D051379:Mice; D008809:Mice, Inbred C3H; D008845:Microinjections; D018613:Microscopy, Confocal; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000378:metabolism* / Q000473:pathology; D018482:Muscle, Skeletal / Q000166:cytology / Q000378:metabolism* / Q000473:pathology; D020388:Muscular Dystrophy, Duchenne / Q000473:pathology; D010957:Plasmids; D012190:Retroviridae / Q000235:genetics
chemical_list: D002232:Carbocyanines; D016189:Dystrophin; D005456:Fluorescent Dyes; D008164:Luminescent Proteins; C089187:cyanine dye 3; D049452:Green Fluorescent Proteins; D002118:Calcium