Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Okayama City, Okayama 700-8558, Japan.
Osteoarthritis Cartilage. 2011 Feb;19(2):222-32. doi: 10.1016/j.joca.2010.11.004. Epub 2010 Nov 19.
To investigate the mechanism of mechanical stress-induced expression and regulation of aggrecanases and examine the role of runt-related transcription factor 2 (RUNX-2) in chondrocyte-like cells.
SW1353 cells were seeded onto stretch chambers at a concentration of 5×10⁴ cells/chamber, and a uni-axial cyclic tensile strain (CTS) (0.5 Hz, 10% stretch) was applied for 30 min. Total RNA was extracted, reverse transcribed, and analyzed by polymerase chain reaction (PCR) and real-time PCR. RUNX-2 overexpression and small interfering RNA (siRNA) targeting RUNX-2 were used to investigate the role of RUNX-2 in CTS-induced gene expression. The involvement of diverse mitogen-activated protein kinase (MAPK) pathways in the activation of RUNX-2, MMP-13 and ADAMTS-5 during CTS was examined by Western blotting.
CTS induced expression of RUNX-2, MMP-13, ADAMTS-4, -5, and -9. Overexpression of RUNX-2 up-regulated expression of MMP-13 and ADAMTS-5, whereas RUNX-2 siRNA resulted in significant down-regulation of mechanically-induced MMP-13 and ADAMTS-5 expression. CTS induced activation of p38 MAPK, and CTS induction of RUNX-2, MMP-13 and ADAMTS-5 mRNA was down-regulated by the selective p38 MAPK inhibitor SB203580 but not by the p44/42 MAPK inhibitor U0126, or the JNK MAPK inhibitor JNK inhibitor II.
RUNX-2 might have a role as a key downstream mediator of p38's ability to regulate mechanical stress-induced MMP-13 and ADAMTS-5 expression.
研究机械应力诱导的聚集蛋白聚糖酶表达和调节的机制，并研究 runt 相关转录因子 2（RUNX-2）在软骨细胞样细胞中的作用。
将 SW1353 细胞以 5×10⁴细胞/腔的浓度接种到拉伸室中，施加单轴循环拉伸应变（CTS）（0.5 Hz，10%拉伸）30 分钟。提取总 RNA，反转录，通过聚合酶链反应（PCR）和实时 PCR 进行分析。使用 RUNX-2 过表达和针对 RUNX-2 的小干扰 RNA（siRNA）来研究 RUNX-2 在 CTS 诱导基因表达中的作用。通过 Western blot 研究不同丝裂原活化蛋白激酶（MAPK）途径在 CTS 过程中对 RUNX-2、MMP-13 和 ADAMTS-5 的激活作用。
CTS 诱导 RUNX-2、MMP-13、ADAMTS-4、-5 和 -9 的表达。RUNX-2 的过表达上调了 MMP-13 和 ADAMTS-5 的表达，而 RUNX-2 siRNA 导致机械诱导的 MMP-13 和 ADAMTS-5 表达显著下调。CTS 诱导 p38 MAPK 激活，并且 CTS 诱导的 RUNX-2、MMP-13 和 ADAMTS-5 mRNA 的表达被选择性 p38 MAPK 抑制剂 SB203580 下调，但不受 p44/42 MAPK 抑制剂 U0126 或 JNK MAPK 抑制剂 JNK 抑制剂 II 的影响。
RUNX-2 可能作为 p38 调节机械应激诱导的 MMP-13 和 ADAMTS-5 表达能力的关键下游介质发挥作用。
