Transforming growth factor-β signaling is upregulated in sporadic inclusion body myositis.
INTRODUCTION
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
These data indicate that upregulation of TGF-β signaling may be an important molecular event in sIBM. Muscle Nerve 55: 741-747, 2017.
['Noda|Seiya|S|', 'Koike|Haruki|H|', 'Maeshima|Shinya|S|', 'Nakanishi|Hirotaka|H|', 'Iijima|Masahiro|M|', 'Matsuo|Koji|K|', 'Kimura|Seigo|S|', 'Katsuno|Masahisa|M|', 'Sobue|Gen|G|']
D003882:Dermatomyositis D005260:Female D006801:Humans D008297:Male D018482:Muscle, Skeletal D018979:Myositis, Inclusion Body D010766:Phosphorylation D017346:Protein Serine-Threonine Kinases D000077293:Receptor, Transforming Growth Factor-beta Type I D000077294:Receptor, Transforming Growth Factor-beta Type II D018125:Receptors, Transforming Growth Factor beta D015398:Signal Transduction D051899:Smad2 Protein D016212:Transforming Growth Factor beta D015854:Up-Regulation
transforming growth factor-β signaling sporadic inclusion body myositis dermatomyositis phosphorylated Smad2 degenerative disease inflammatory myopathy