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The molecular chaperone HSP47 rapidly senses gravitational changes in myoblasts
Author(s) -
Oguro Asami,
Sakurai Takashi,
Fujita Yoshinobu,
Lee Sachiko,
Kubota Hiroshi,
Nagata Kazuhiro,
Atomi Yoriko
Publication year - 2006
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1111/j.1365-2443.2006.01021.x
Subject(s) - hypergravity , biology , decorin , extracellular matrix , microbiology and biotechnology , endoplasmic reticulum , myocyte , messenger rna , skeletal muscle , in vivo , anatomy , biochemistry , genetics , proteoglycan , gene , astrobiology
Skeletal muscle unloading induced by spaceflight or bed rest leads to muscle atrophy. It is unclear how muscle atrophy is caused and how muscles respond to microgravity. We addressed the response of collagen and its chaperone system to gravitational forces. We show here that expression of HSP47, a collagen‐specific molecular chaperone, responds to gravitational changes, including microgravity and hypergravity in vitro and in vivo . By using the method hindlimb suspension of rats, which mimics microgravity conditions, we demonstrated that the expression of Hsp47 mRNA decreased within 1 day and the mRNA levels of collagen types I and IV were subsequently reduced. In contrast, hypergravity stimulated HSP47 expression. HSP47 and collagen types I and IV were localized intracellularly in the endoplasmic reticulum and/or Golgi apparatus of myoblasts, as expected. Intriguingly, Hsp47 mRNA levels in cultured myoblasts increased significantly with hypergravity treatment at 40G for 2 h, and decreased with microgravity treatment at almost 0G for 1–2 h. Collagen mRNA levels were also altered, although changes were slower and less pronounced compared with those for HSP47. The gravity‐regulated HSP47 may play a role in the maintenance of the extracellular matrix by modulating collagen production at the primary stage of adaptation.