title: Increased skeletal muscle expression of the endoplasmic reticulum chaperone GRP78 in patients with myasthenia gravis.
abstract: In myasthenia gravis (MG), damage to neuromuscular junctions may induce endoplasmic reticulum (ER) stress in skeletal muscles. In the current study, skeletal muscles obtained from patients with MG exhibited upregulation of glucose-regulated protein 78 (GRP78) mRNA that was activated by ER stress. Furthermore, GRP78 mRNA expression was higher in patients with MG and myositis than in patients with non-myopathy. We also observed a significant positive correlation between GRP78 mRNA expression and GRP78 protein levels and between GRP78 mRNA expression and age of MG onset. Our findings suggest that muscle weakness in MG might be caused by both neuromuscular junction disruption and ER stress.
authors.affiliation: Department of Neurology and Neurobiology of Aging, Kanazawa University Graduate School of Medical Science, 13-1 Takara-Machi, Kanazawa 920-8640, Japan. Electronic address: neuiwasa@med.kanazawa-u.ac.jp.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Iwasa
authors.affiliation: Department of Neurology and Neurobiology of Aging, Kanazawa University Graduate School of Medical Science, 13-1 Takara-Machi, Kanazawa 920-8640, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Nambu
authors.affiliation: Department of Neurology, Iou National Hospital, Ni 73-1 Iwade-Machi, Kanazawa 920-0192, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Motozaki
authors.affiliation: Department of Neurology, Takaoka Koseiren Hospital, 5-10 Eiraku-Cho, Takaoka 933-8555, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Furukawa
authors.affiliation: Health Service Center, Kanazawa University, Kakuma-Machi, Kanazawa 920-1192, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Yoshikawa
authors.affiliation: Department of Neurology and Neurobiology of Aging, Kanazawa University Graduate School of Medical Science, 13-1 Takara-Machi, Kanazawa 920-8640, Japan.
authors.forename: Masahito
authors.initials: M
authors.lastname: Yamada
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000091342:Endoplasmic Reticulum Chaperone BiP; D005260:Female; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*; D009157:Myasthenia Gravis / Q000150:complications / Q000473:pathology*; D012333:RNA, Messenger / Q000378:metabolism; D018709:Statistics, Nonparametric; D013945:Thymoma / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D015854:Up-Regulation / Q000502:physiology*; D055815:Young Adult
chemical_list: D000091342:Endoplasmic Reticulum Chaperone BiP; C000717247:HSPA5 protein, human; D006360:Heat-Shock Proteins; D012333:RNA, Messenger
keywords: Endoplasmic reticulum (ER) stress response; Glucose-regulated protein 78 (GRP78); Myasthenia gravis; Skeletal muscle