Inhibition of CRY2 by STAT3/miRNA-7-5p Promotes Osteoblast Differentiation through Upregulation of CLOCK/BMAL1/P300 Expression
Inhibition of CRY2 by STAT3/miRNA-7-5p Promotes Osteoblast Differentiation through Upregulation of CLOCK/BMAL1/P300 Expression
复制标题
STAT3/miRNA-7-5p 抑制 CRY2 通过上调 CLOCK/BMAL1/P300 表达促进成骨细胞分化
DOI：
10.1016/j.omtn.2019.12.020
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发表时间：
2020-03-06
影响因子：
8.8
通讯作者：
Hong, Yang
中科院分区：
文献类型：
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作者：
Tang, Zhenghui;Xu, Tianyuan;Hong, Yang
越来越多的证据表明，隐色素昼夜节律调节蛋白(CRY)已成为成骨分化的重要调节因子。然而，相关的机制相当难以捉摸。在本研究中，我们发现CRY2基因的敲除下调了矮小相关转录因子2(Runx2)、碱性磷酸酶(ALP)、骨钙素(OCN)和骨桥蛋白(OPN)的表达，从而促进成骨细胞的分化。进一步的研究证实，CRY2直接被microRNA(MiR)-7-5p靶向，在成骨细胞分化过程中高度诱导。通过miR-7-5p的过度表达和成骨细胞的诱导，Runx2、ALP、I型胶原α1(Col1a1)和OCN的表达上调。此外，信号转导和转录激活因子3(STAT3)转录激活miR-7-5p，显著增强上述成骨标记基因的表达和矿物质形成。然而，CRY2的过表达可阻断miR-7-5p过表达所诱导的成骨分化。沉默CRY2解开了CRY2与昼夜运动输出周期kaput(Clock)/脑和肌肉Arnt-like 1(BMAL1)复合体的结合，释放了Clock/BMAL1，从而促进了Clock/BMAL1与P300 E-box启动子区域的结合，从而刺激了P300的转录。P300随后促进组蛋白3的乙酰化，并与Runx2形成转录复合体，以促进成骨。综上所述，我们的研究表明，CRY2被STAT3/miR-7-5p抑制，通过CLOCK/BMAL1/P300信号促进成骨分化。所涉及的分子可能是治疗骨质疏松症的潜在靶点。
Accumulating evidence indicates that cryptochrome circadian regulatory (CRY) proteins have emerged as crucial regulators of osteogenic differentiation. However, the associated mechanisms are quite elusive. In this study, we show that knockdown of CRY2 downregulated the expression of runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP), osteocalcin (OCN), and osteopontin (OPN) to facilitate osteoblast differentiation. Further study identified that CRY2 was directly targeted by microRNA (miR)-7-5p, which was highly induced during osteoblast differentiation. The expression of Runx2, ALP, collagen type I alpha 1 (Col1a1), and OCN was upregulated by overexpression of miR-7-5p and induction of osteoblast differentiation. Moreover, signal transducer and activator of transcription 3 (STAT3) transcriptionally activated miR-7-5p to significantly enhance the expression of above osteogenic marker genes and mineral formation. However, overexpression of CRY2 abolished the osteogenic differentiation induced by miR-7-5p overexpression. Silencing of CRY2 unraveled the binding of CRY2 with the circadian locomotor output cycles kaput (CLOCK)/brain and muscle ARNT-like 1 (BMAL1) complex to release CLOCK/BMAL1, which facilitated the binding of CLOCK/BMAL1 to the promoter region of the P300 E-box to stimulate the transcription of P300. P300 subsequently promoted the acetylation of histone 3 and the formation of a transcriptional complex with Runx2 to enhance osteogenesis. Taken together, our study revealed that CRY2 is repressed by STAT3/miR-7-5p to promote osteogenic differentiation through CLOCK/BMAL1/P300 signaling. The involved molecules may be potentially targeted for treatment of osteoporosis.