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Mechanisms of osteoblastic MG‐63 cell contraction and mRNA expression in stress‐relaxed collagen gels
Author(s) -
Hart David A.,
Parreno Justin,
deHemptinne Isabelle
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.774.5
Subject(s) - nocodazole , cytochalasin d , rho associated protein kinase , cytoskeleton , contraction (grammar) , microfilament , microbiology and biotechnology , stress fiber , rho kinase inhibitor , chemistry , messenger rna , gene expression , kinase , microtubule , biology , endocrinology , cell , biochemistry , gene
Culture of osteoblast‐like MG‐63 cells within collagen gels results in the generation of intrinsic stress. Release of the gels from attachment results in contraction and significantly enhanced MMP‐1, MMP‐3, and α2 integrin mRNA levels. To understand the role of cytoskeletal elements and signaling pathways involved in contraction and gene expression, MG‐63 cells were cultured in collagen gels for 24 hours, released, and then immediately treated with cytoskeletal depolymerization agents or kinase inhibitors. Contraction was measured, RNA isolated, and real‐time PCR analysis was performed. The results showed that: (1) cytochalasin D treatment (microfilaments) inhibited contraction and depressed MMP‐1, MMP‐3, and α2 mRNA levels; (2) Nocodazole treatment (microtubules) enhanced early contraction and elevated mRNA levels for MMP‐3; (3) ROCK inhibitor treatment (Y27632) inhibited contraction and depressed MMP‐3 and α2 integrin mRNA levels; (4) the ERK1/2 inhibitor, U0126, did not affect contraction, but depressed MMP‐1, MMP‐3, and α2 mRNA mRNA levels; and (5) treatment with the p38 MAP kinase inhibitor SB203580 was ineffective. These results suggest that collagen gel contraction and gene expression is dependent on the tensegrity balance between microfilaments and microtubules, and the ROCK pathway, while gene expression but not contraction is also dependent on the ERK1/2 MAP kinase pathway.