Transforming growth factor-β signaling is upregulated in sporadic inclusion body myositis.
In this study we aimed to determine whether transforming growth factor-β (TGF-β) signaling is dysregulated in sporadic inclusion body myositis (sIBM) muscle samples.



We examined TGF-β signaling markers in muscle samples from 24 sIBM patients and compared them with those from 10 dermatomyositis (DM) patients using immunohistochemistry and Western blot analyses.



Compared with the DM muscle fibers, the sIBM muscle fibers exhibited greater TGF-β, TGF-β receptor type I (TβRI), and TGF-β receptor type II (TβRII) immunoreactivity in the cytoplasm, as well as greater phosphorylated Smad2 (pSmad2) immunoreactivity in the myonuclei. The signal intensities of TGF-β, TβRI, and TβRII immunoreactivity correlated significantly with muscle fiber cross-sectional areas. Western blot analyses indicated higher expression levels of TGF-β, TβRI, TβRII, and pSmad2 in the sIBM muscle samples than in the DM muscle samples.



These data indicate that upregulation of TGF-β signaling may be an important molecular event in sIBM. Muscle Nerve 55: 741-747, 2017.
Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Seiya
S
Noda
Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Haruki
H
Koike
Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan.|Department of Neurology, Nagoya Ekisaikai Hospital, Nagoya, Japan.
Shinya
S
Maeshima
Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Hirotaka
H
Nakanishi
Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Masahiro
M
Iijima
Department of Neurology, Kariya Toyota General Hospital, Kariya, Japan.
Koji
K
Matsuo
Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Seigo
S
Kimura
Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Masahisa
M
Katsuno
Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan.|Research Division of Dementia and Neurodegenerative Disease, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.
Gen
G
Sobue
D003882:Dermatomyositis / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology; D018979:Myositis, Inclusion Body / Q000378:metabolism* / Q000473:pathology; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D000077293:Receptor, Transforming Growth Factor-beta Type I; D000077294:Receptor, Transforming Growth Factor-beta Type II; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D051899:Smad2 Protein / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000378:metabolism*; D015854:Up-Regulation
D018125:Receptors, Transforming Growth Factor beta; C497782:SMAD2 protein, human; D051899:Smad2 Protein; D016212:Transforming Growth Factor beta; D017346:Protein Serine-Threonine Kinases; D000077293:Receptor, Transforming Growth Factor-beta Type I; D000077294:Receptor, Transforming Growth Factor-beta Type II
degenerative disease; dermatomyositis; inflammatory myopathy; phosphorylated Smad2; signaling; sporadic inclusion body myositis; transforming growth factor-β