title: Dysferlinopathy Fibroblasts Are Defective in Plasma Membrane Repair.
abstract: BACKGROUND
  Dysferlin is a sarcolemmal protein that is defective in Miyoshi myopathy and limb-girdle muscular dystrophy type 2B, and is involved in sarcolemmal repair. Primary cultured myoblasts and myotubes established from patient muscle biopsies have been widely utilized to explore the molecular mechanism of dysferlinopathy.
  
  
  OBJECTIVE
  The purpose of this study was to explore the possible utility of dermal fibroblasts from dysferlin-deficient patients and SJL mice as a tool for studying dysferlinopathy.
  
  
  METHODS
  Dysferlin protein expression in fibroblasts from dysferlin-deficient patients and SJL mice was analyzed by immunoblotting and immunocytochemistry. The membrane wound-repair assay was performed on the fibroblasts using a confocal microscope equipped with a UV-laser. The membrane blebbing assay using hypotonic shock, in which normal membrane blebbing is detected only in the presence of dysferlin, was also performed using human and mouse fibroblasts.
  
  
  RESULTS
  Mis-sense mutated dysferlin was expressed at a very low level in fibroblasts from a dysferlinopathy patient, and lower expression level of truncated dysferlin was observed in SJL mouse fibroblast. Fibroblasts from patients with dysferlinopathy and SJL mice showed attenuated membrane repair and did not form membrane blebs in response to hypoosmotic shock. Proteosomal inhibitior increased mis-sense mutated or truncated dysferlin levels, and restored membrane blebbing, however, proteosomal inhibition failed to improve levels of dysferlin with non-sense or frame-shift mutation.
  
  
  CONCLUSIONS
  Fibroblasts from dysferlinopathy patients and SJL mice showed attenuated plasma membrane repair, and could be a tool for studying dysferlinopathy.
authors.affiliation: Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan; Department of Neurophysiology, Tokyo Medical University, Shinjuku, Tokyo 160-8402, Japan; Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), 4-1-1 Ogawa-Higashi, Kodaira, Tokyo 187-8502, Japan.
authors.forename: Chie
authors.initials: C
authors.lastname: Matsuda
authors.affiliation: Biomedical Research Institute, AIST, 1-8-31 Midorigaoka, Ikeda 563-8577, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Kiyosue
authors.affiliation: Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), 4-1-1 Ogawa-Higashi, Kodaira, Tokyo 187-8502, Japan; Department of Genome Medicine Development, Medical Genome Center (MGC), National Institute of Neuroscience, NCNP, 4-1-1 Ogawa-Higashi, Kodaira, Tokyo 187-8502, Japan.
authors.forename: Ichizo
authors.initials: I
authors.lastname: Nishino
authors.affiliation: Department of Genome Medicine Development, Medical Genome Center (MGC), National Institute of Neuroscience, NCNP, 4-1-1 Ogawa-Higashi, Kodaira, Tokyo 187-8502, Japan; Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, NCNP, 4-1-1 Ogawa-Higashi, Kodaira, Tokyo 187-8502, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Goto
authors.affiliation: Department of Neurophysiology, Tokyo Medical University, Shinjuku, Tokyo 160-8402, Japan; Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), 4-1-1 Ogawa-Higashi, Kodaira, Tokyo 187-8502, Japan.
authors.forename: Yukiko K
authors.initials: YK
authors.lastname: Hayashi