Expression of tumor necrosis factor-alpha in regenerating muscle fibers in inflammatory and non-inflammatory myopathies.
The expression level of tumor necrosis factor (TNF)-alpha is elevated in idiopathic inflammatory myopathies and Duchenne muscular dystrophy (DMD), but the precise role of TNF-alpha is unknown. To elucidate the possible role of TNF-alpha, we investigated the expression of TNF-alpha and its receptor in polymyositis (PM), dermatomyositis (DM), and DMD using in situ hybridization (ISH) and immunohistochemistry. We showed that TNF-alpha mRNA and protein were present in muscle fibers. TNF-alpha-positive fibers were observed in all cases of PM, DM and DMD, but were rare or absent in neurogenic disorders and normal controls. The proportion of TNF-alpha-positive fiber showed a significant positive correlation with the proportion of regenerating fibers that were positive for the developmental form of myosin heavy chain (MHC-d). The number of TNF receptor-positive fibers was small. Some muscle fibers expressed both TNF-alpha and its receptor simultaneously. Our results indicate that TNF-alpha is produced and expressed by muscle fibers and associated with muscle regeneration.
Kuru
Satoshi
S
Department of Neurology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Japan.
Inukai
Akira
A
Kato
Takashi
T
Liang
Yideng
Y
Kimura
Seigo
S
Sobue
Gen
G
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D003882:Dermatomyositis / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D008875:Middle Aged; D018485:Muscle Fibers, Skeletal / Q000473:pathology; D018482:Muscle, Skeletal / Q000473:pathology / Q000502:physiology*; D009135:Muscular Diseases / Q000378:metabolism* / Q000473:pathology; D020388:Muscular Dystrophy, Duchenne / Q000378:metabolism / Q000473:pathology; D018995:Myosin Heavy Chains / Q000378:metabolism; D017285:Polymyositis / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000032:analysis; D018124:Receptors, Tumor Necrosis Factor / Q000096:biosynthesis; D012038:Regeneration; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*
D012333:RNA, Messenger; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha; D018995:Myosin Heavy Chains