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Inhibition of HSP70 and a Collagen-Specific Molecular Chaperone (HSP47) Expression in Rat Osteoblasts by MicrogravityRat osteoblasts were cultured aboard a space shuttle for 4 or 5 days. Cells were exposed to 1alpha, 25 dihydroxyvitamin D(3) during the last 20 h and then solubilized by guanidine solution. The mRNA levels for molecular chaperones were analyzed by semi-quantitative RT-PCR. ELISA was used to quantify TGF-beta1 in the conditioned medium. The HSP70 mRNA levels in the flight cultures were almost completely suppressed, as compared to the ground (1 x g) controls. The inducible HSP70 is known as the major heat shock protein that prevents stress-induced apoptosis. The mean mRNA levels for the constitutive HSC73 in the flight cultures were reduced to 69%, approximately 60% of the ground controls. HSC73 is reported to prevent the pathological state that is induced by disruption of microtubule network. The mean HSP47 mRNA levels in the flight cultures were decreased to 50% and 19% of the ground controls on the 4th and 5th days. Concomitantly, the concentration of TGF-beta1 in the conditioned medium of the flight cultures was reduced to 37% and 19% of the ground controls on the 4th and 5th days. HSP47 is the collagen-specific molecular chaperone that controls collagen processing and quality and is regulated by TGF-beta1. Microgravity differentially modulated the expression of molecular chaperones in osteoblasts, which might be involved in induction and/or prevention of osteopenia in space.
Document ID
20040091410
Acquisition Source
Johnson Space Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Kumei, Yasuhiro
(Tokyo Medical and Dental Univ. Japan)
Morita, Sadao
(Tokyo Medical and Dental Univ. Japan)
Shimokawa, Hitoyata
(Tokyo Medical and Dental Univ. Japan)
Ohya, Kei'ichi
(Tokyo Medical and Dental Univ. Japan)
Akiyama, Hideo
(Toray Research Center Kamakura, Japan)
Hirano, Masahiko
(Toray Research Center Kamakura, Japan)
Sams, Clarence F.
(NASA Johnson Space Center Houston, TX, United States)
Whitson, Peggy A.
(NASA Johnson Space Center Houston, TX, United States)
Date Acquired
August 21, 2013
Publication Date
December 1, 2003
Publication Information
Publication: Annals of the New York Academy of Sciences
Volume: 1010
ISSN: 0077-8923
Subject Category
Life Sciences (General)
Report/Patent Number
JSC-CN-8547
Distribution Limits
Public
Copyright
Other

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