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In vitro alterations in cytoskeletal tensional homeostasis control gene expression in tendon cells
Author(s) -
Lavagnino Michael,
Arnoczky Steven P.
Publication year - 2005
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1016/j.orthres.2005.04.001
Subject(s) - cytoskeleton , microbiology and biotechnology , in vitro , homeostasis , gene expression , tendon , biology , gene , cell , anatomy , genetics
An in vitro collagen gel system was used to determine the effect of alterations in cytoskeletal tensional homeostasis on gene expression in tendon cells. Collagen gel matrices, seeded with rat tail tendon cells, underwent cytochalasin D and gel contraction treatments designed to alter the internal cytoskeletal homeostasis of the cells. Gels were examined for cytoskeletal organization using a rhodamine phalloidin stain for actin. The effect of altered cytoskeletal organization on mRNA expression of a catabolic (interstitial collagenase) and anabolic (α1(I) collagen) gene was examined using northern blot analysis. Tendon cells in adhered gels demonstrated a highly organized cytoskeleton and showed evidence of α1(I) collagen mRNA expression but no evidence of collagenase mRNA expression. Treatment of the attached gel with cytochalasin D disrupted the cytoskeletal organization and resulted in the upregulation of collagenase mRNA and the inhibition of α1(I) collagen mRNA expression. Release of the gels resulted in a cell mediated gel contraction, an immediate loss of cytoskeletal organization, and an mRNA expression pattern similar to that seen with cytochalasin D treatment. Isometric contraction of the gel on itself or around a 3‐point traction device resulted in an mRNA expression pattern similar to the adhered gel. Gene expression in the contracted gels could be reversed through chemical cytoskeletal disruption or removal of the traction device which permitted further gel contraction. The results of the study suggest that tendon cells can establish an internal cytoskeletal tension through interactions with their local extracellular environment. Alterations in this tension appear to control the expression of both catabolic and anabolic genes in a reciprocal manner. © 2005 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.