Cyclic compression-induced p38 activation and subsequent MMP13 expression requires Rho/ROCK activity in bovine cartilage explants
Cyclic compression-induced p38 activation and subsequent MMP13 expression requires Rho/ROCK activity in bovine cartilage explants
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DOI：
10.1007/s00011-012-0500-4
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发表时间：
2012-10-01
影响因子：
6.7
通讯作者：
Fukuda, Kanji
中科院分区：
文献类型：
--
作者：
Nakagawa, Koichi;Teramura, Takeshi;Fukuda, Kanji
过度的机械应力对软骨造成的基质降解，导致骨关节炎（OA）。基质金属蛋白酶13（MMP 13）是OA的主要催化酶，p38在其诱导中起重要作用。然而，诱导p38活化的精确途径尚未阐明。我们假设小GT_1 β Rho及其效应子ROCK可能在机械应力诱导的基质降解途径的上部发挥作用。牛掌指关节软骨外植体在1 MPa的动态压力下加载6 h，有或没有ROCK特异性抑制剂Y27632或/和p38特异性抑制剂SB 202190。Western blot和/或定量RT-PCR检测MMP 13表达和p38磷酸化水平。用Rho结合域谷胱甘肽S-转移酶融合蛋白pull-down法检测Rho活性，循环压缩引起Rho激活、p38磷酸化和MMP 13表达。Y27632和SB 202190均能阻断机械应力诱导的p38磷酸化和随后的MMP 13表达，本研究结果表明，p38磷酸化和MMP 13表达受Rho/ROCK激活的调节，并支持Rho/ROCK处于机械应力上部的潜在新途径-在软骨中诱导由p38和MMP 13组成的基质变性级联反应。
Excessive mechanical stress on the cartilage causes the degradation of the matrix, leading to the osteoarthritis (OA). Matrix metalloproteinases 13 (MMP13) is a major catalytic enzyme in OA and p38 plays an important role in its induction. However, precise pathway inducing p38 activation has not been elucidated. We hypothesized here that the small GTPase Rho and its effector ROCK might function in upper part of the mechanical stress-induced matrix degeneration pathway.Bovine metacarpal phalangeal articular cartilage explants were loaded with 1 MPa dynamic compression for 6 h with or without a ROCK specific inhibitor Y27632 or/and a p38 specific inhibitor SB202190. Then p38 phosphorylation and MMP13 expression were assessed by western blot or/and quantitative RT-PCR. Rho-activity was measured by pull-down assay using glutathione S-transferase fusion protein of Rho binding domain.Cyclic compression caused Rho activation, p38 phosphorylation and MMP13 expression. Both Y27632 and SB202190 were found to block the mechanical stress-enhanced p38 phosphorylation and subsequent MMP13 expression.The present results show that p38 phosphorylation and MMP13 expression are regulated by Rho/ROCK activation, and support the potential novel pathway that Rho/ROCK is in the upper part of the mechanical stress-induced matrix degeneration cascade in cartilage comprised of p38 and MMP13.