Myostatin is increased and complexes with amyloid-beta within sporadic inclusion-body myositis muscle fibers.
Myostatin is a negative regulator of muscle mass and strength. Sporadic inclusion-body myositis (s-IBM) is the most common degenerative muscle disease of older persons and is characterized by pronounced muscle wasting. s-IBM is of unknown etiology and pathogenesis, and it lacks definitive treatment. We have now demonstrated in samples from 12 s-IBM biopsies that: (1) by light and electron microscopic immunocytochemistry, myostatin/myostatin precursor is accumulated within muscle fibers and co-localized with amyloid-beta (Abeta); (2) by immunoblots, both myostatin and myostatin precursor are increased; and (3) by immunoprecipitation, myostatin precursor complexes with Abeta. Our study suggests that myostatin/myostatin precursor, either alone, or bound to Abeta, may play a novel role in the pathogenesis of s-IBM.
USC Neuromuscular Center, Department of Neurology, University of Southern California Keck School of Medicine, Good Samaritan Hospital, 637 S. Lucas Ave, Los Angeles, CA, 90017-1912, USA.
Sławomir
S
Wójcik
W King
WK
Engel
Janis
J
McFerrin
Valerie
V
Askanas
D016229:Amyloid beta-Peptides / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D016253:Microscopy, Immunoelectron; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology; D018979:Myositis, Inclusion Body / Q000378:metabolism* / Q000473:pathology; D055435:Myostatin; D016212:Transforming Growth Factor beta / Q000378:metabolism*
D016229:Amyloid beta-Peptides; C525911:MSTN protein, human; D055435:Myostatin; D016212:Transforming Growth Factor beta