State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, Department of oral and Maxillofacial Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
Cell Prolif. 2018 Aug;51(4):e12453. doi: 10.1111/cpr.12453. Epub 2018 Mar 5.
To investigate the mechanism of mechanical stimulation in bone formation and regeneration during distraction osteogenesis.
In this study, microarray technology was used to investigate the time course of bone-related molecular changes in distraction osteogenesis in rats. Real-time PCR and Western-blot analyses were used to confirm the expression of genes identified in microarrays. Meanwhile, we used a lentivirus vector to inhibit Fak expression, in order to identify the osteogenic effect of Fak and Fak-Mapk pathway during distraction osteogenesis.
Several components of the Wnt and Hippo pathways were found to be up- or down-regulated during distraction osteogenesis by microarray. Meanwhile, it was found that Fak, Src, Raf-1, Erk1, Jnk and p38-Mapk were up-regulated during gradual distraction, compared with consolidation. To further determine whether Fak-Mapk pathway played an important role in distraction osteogenesis, Fak was disrupted with a lentivirus vector. The expressions levels of p-Fak, p-Erk1/2, p-JNK and p-p38Mapk were decreased. Meanwhile, a poor early and late osteogenesis effect was found in the shRNA-Fak group.
It was inferred that the mechanical stimulus induces increased expression of Fak and activates Fak-Mapk pathway, by activation of Erk, Jnk and p38-Mapk pathway, and that Fak at least, in part, plays an important role in maintaining osteogenic effect by activating Fak-Mapk pathway during distraction osteogenesis.
研究机械刺激在牵张成骨过程中骨形成和再生中的作用机制。
本研究采用基因芯片技术研究大鼠牵张成骨过程中与骨相关的分子变化的时程。采用实时 PCR 和 Western blot 分析来验证基因芯片中鉴定的基因的表达。同时，我们使用慢病毒载体来抑制 Fak 的表达，以确定 Fak 和 Fak-Mapk 通路在牵张成骨过程中的成骨作用。
通过基因芯片发现，在牵张成骨过程中，Wnt 和 Hippo 通路的几个组成部分被上调或下调。同时发现，与整合期相比，在逐渐牵张过程中 Fak、Src、Raf-1、Erk1、Jnk 和 p38-Mapk 被上调。为了进一步确定 Fak-Mapk 通路在牵张成骨过程中是否发挥重要作用，我们使用慢病毒载体破坏 Fak。p-Fak、p-Erk1/2、p-JNK 和 p-p38Mapk 的表达水平降低。同时，在 shRNA-Fak 组中发现早期和晚期成骨效果较差。
可以推断，机械刺激通过激活 Erk、Jnk 和 p38-Mapk 通路，导致 Fak 的表达增加，从而激活 Fak-Mapk 通路，Fak 通过激活 Fak-Mapk 通路在牵张成骨过程中至少部分发挥维持成骨效应的重要作用。
