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Human osteoblast-like cells respond to mechanical strain with increased bone matrix protein production independent of hormonal regulationExposure of osteosarcoma cell lines to chronic intermittent strain increases the activity of mechano-sensitive cation (SA-cat) channels. The impact of mechano-transduction on osteoblast function has not been well studied. We analyzed the expression and production of bone matrix proteins in human osteoblast-like osteosarcoma cells, OHS-4, in response to chronic intermittent mechanical strain. The OHS-4 cells exhibit type I collagen production, 1,25-Dihydroxyvitamin D-inducible osteocalcin, and mineralization of the extracellular matrix. The matrix protein message level was determined from total RNA isolated from cells exposed to 1-4 days of chronic intermittent strain. Northern analysis for type I collagen indicated that strain increased collagen message after 48 h. Immunofluorescent labeling of type I collagen demonstrated that secretion was also enhanced with mechanical strain. Osteopontin message levels were increased several-fold by the application of mechanical load in the absence of vitamin D, and the two stimuli together produced an additive effect. Osteocalcin secretion was also increased with cyclic strain. Osteocalcin levels were not detectable in vitamin D-untreated control cells. However, after 4 days of induced load, significant levels of osteocalcin were observed in the medium. With vitamin D present, osteocalcin levels were 4 times higher in the medium of strained cells compared to nonstrained controls. We conclude that mechanical strain of osteoblast-like cells is sufficient to increase the transcription and secretion of matrix proteins via mechano-transduction without hormonal induction.
Document ID
20050000241
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Harter, L. V.
(Jewish Hospital, Washington University Medical Center St. Louis, Missouri 63110)
Hruska, K. A.
Duncan, R. L.
Date Acquired
August 22, 2013
Publication Date
February 1, 1995
Publication Information
Publication: Endocrinology
Volume: 136
Issue: 2
ISSN: 0013-7227
Subject Category
Aerospace Medicine
Funding Number(s)
CONTRACT_GRANT: N01-HD-6-2915
CONTRACT_GRANT: AR-39561
CONTRACT_GRANT: AR-320187
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Number 40-40
Non-NASA Center
NASA Program Space Biology
NASA Discipline Musculoskeletal

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