ATRA Signaling Regulates the Expression of COL9A1 through BMP2‐WNT4‐RUNX1 Pathway in Antler Chondrocytes
ATRA Signaling Regulates the Expression of COL9A1 through BMP2‐WNT4‐RUNX1 Pathway in Antler Chondrocytes
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DOI：
10.1002/jez.b.22756
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发表时间：
2017-06
期刊：
影响因子：
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通讯作者：
Hong-Liang Zhang;B. Guo;Zhan‐Qing Yang;Cui-Cui Duan-Cui;S. Geng;Kai Wang;Hai-Fan Yu;Z. Yue
中科院分区：
文献类型：
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作者：
Hong-Liang Zhang;B. Guo;Zhan‐Qing Yang;Cui-Cui Duan-Cui;S. Geng;Kai Wang;Hai-Fan Yu;Z. Yue
尽管全反式维甲酸(ATRA)参与了软骨生长发育的调控，但其调控机制尚不清楚。在此，我们发现全反式维甲酸可以诱导鹿角软骨细胞COL9A1的表达。细胞维甲酸结合蛋白2(CRABP2)的沉默可以抑制ATRA诱导的COL9A1的上调，而CRABP2的过度表达则起相反的作用。RA受体α激动剂Am80可诱导COL9A1的表达，而RARα拮抗剂RO41-5253或RXRATRA小干扰α可明显阻断COL9A1的表达。在鹿角软骨细胞中，细胞色素P26A1和细胞色素26B1降低了全反式维甲酸对COL9A1的敏感性。同时，骨形态发生蛋白2(BMP2)和WNT4介导全反式维甲酸对COL9A1表达的调节。Wnt4基因敲除可阻断BMP2过表达对COL9A1的抑制作用。相反，WNT4的结构性表达逆转了BMP2 siRNA诱导的COL9A1的上调。这些结果提示，WNT4可能作用于BMP2下游，介导ATRA对COL9A1表达的影响。进一步的分析表明，矮小相关转录因子1(RUNX1)的减弱可以阻止ATRA对COL9A1表达的刺激，而外源rRUNX1则进一步增强了这一效应。此外，RUNX1可能是BMP2和WNT4调节COL9A1表达的中间产物。综上所述，ATRA信号可能通过BMP2-WNT4-RUNX1途径调节COL9A1的表达。
Although all-trans retinoic acid (ATRA) is involved in the regulation of cartilage growth and development, its regulatory mechanisms remain unknown. Here, we showed that ATRA could induce the expression of COL9A1 in antler chondrocytes. Silencing of cellular retinoic acid binding protein 2 (CRABP2) could impede the ATRA-induced upregulation of COL9A1, whereas overexpression of CRABP2 presented the opposite effect. RARα agonist Am80 induced the expression of COL9A1, whereas treatment with RARα antagonist Ro 41-5253 or RXRα small-interfering RNA (siRNA) caused an obvious blockage of ATRA on COL9A1. In antler chondrocytes, CYP26A1 and CYP26B1 weakened the sensitivity of ATRA to COL9A1. Simultaneously, Bone morphogenetic protein 2 (BMP2) and WNT4 mediated the regulation of ATRA on COL9A1 expression. Knockdown of WNT4 could abrogate the inhibitory effect of BMP2 overexpression on COL9A1. Conversely, constitutive expression of WNT4 reversed the upregulation of COL9A1 elicited by BMP2 siRNA. Together these data indicated that WNT4 might act downstream of BMP2 to mediate the effect of ATRA on COL9A1 expression. Further analysis evidenced that attenuation of runt-related transcription factor 1 (RUNX1) could prevent the stimulation of ATRA on COL9A1 expression, while exogenous rRUNX1 further enhanced this effectiveness. Moreover, RUNX1 might serve as an intermediate to mediate the regulation of BMP2 and WNT4 on COL9A1 expression. Collectively, ATRA signaling might regulate the expression of COL9A1 through BMP2-WNT4-RUNX1 pathway.