Hu Qin-Xiao, Li Xue-Dong, Xie Peng, Wu Chu-Cheng, Zheng Gui-Zhou, Lin Fei-Xiang, Xie Da, Zhang Qi-Hao, Liu De-Zhong, Wang Yun-Guo, Chang Bo, Du Shi-Xin
Department of Orthopedics, The First Affiliated Hospital of Shantou University Medical CollegeShantou 515041, Guangdong, P. R. China.
Department of Orthopedics, The 3rd Affiliated Hospital (The Affiliated Luohu Hospital) of Shenzhen UniversityShenzhen 518000, Guangdong, P. R. China.
Am J Transl Res. 2017 May 15;9(5):2296-2305. eCollection 2017.
Recent studies have indicated that ATRA inhibits chondrogenesis and can lead to congenital clubfoot (CCF). The molecular mechanism of ATRA-induced chondrogenesis is not clear. As RhoA/ROCK and SDF-1/CXCR4 signaling play important molecular roles for a variety of cellular processes, we hypothesized that RhoA/ROCK2 and SDF-1/CXCR4 signaling are involved in ATRA-induced chondrogenesis in rat embryo hind limb bud mesenchymal cells (rEHBMCs). We found that ATRA dose-dependently inhibits proliferation and expression of chondrogenic transcription factors (SOX9 and COL2A1) in rEHBMCs. In contrast, ATRA increases the expression of ROCK2, SDF-1 and CXCR4. Pharmacological inhibition of ROCK signaling and SDF-1/CXCR4 signaling by Y27632 and AMD3100, respectively, resulted in elevated expression of SOX9 and COL2A1. In addition, we found that disturbing SDF-1/CXCR4 signaling by AMD3100 decreases ATRA-induced ROCK2 expression. In vivo studies we also confirm that SOX9 expression of early-stage cartilage progenitors in the proliferative zone and COL2A1 expression in prehypertrophic chondrocytes are decreased in ATRA-treated rat embryo hind limb. Together, these results show that ATRA activates SDF-1/CXCR4/ROCK2 signaling to inhibit chondrogenesis to lead to CCF by suppressing differentiation through down-regulation of SOX9 and COL2A1 expression in rat embryo hind limb bud mesenchymal cells.
最近的研究表明，全反式维甲酸（ATRA）可抑制软骨形成，并可导致先天性马蹄内翻足（CCF）。ATRA诱导软骨形成的分子机制尚不清楚。由于RhoA/ROCK和SDF-1/CXCR4信号在多种细胞过程中发挥重要的分子作用，我们推测RhoA/ROCK2和SDF-1/CXCR4信号参与了ATRA诱导的大鼠胚胎后肢芽间充质细胞（rEHBMCs）的软骨形成。我们发现，ATRA在rEHBMCs中剂量依赖性地抑制增殖和软骨形成转录因子（SOX9和COL2A1）的表达。相反，ATRA增加ROCK2、SDF-1和CXCR4的表达。分别用Y27632和AMD3100对ROCK信号和SDF-1/CXCR4信号进行药理学抑制，导致SOX9和COL2A1表达升高。此外，我们发现用AMD3100干扰SDF-1/CXCR4信号可降低ATRA诱导的ROCK2表达。在体内研究中，我们还证实，在经ATRA处理的大鼠胚胎后肢中，增殖区早期软骨祖细胞的SOX9表达和前肥大软骨细胞中的COL2A1表达降低。总之，这些结果表明，ATRA激活SDF-1/CXCR4/ROCK2信号以抑制软骨形成，通过下调大鼠胚胎后肢芽间充质细胞中SOX9和COL2A1的表达来抑制分化，从而导致CCF。
