miR-23b targets Smad 3 and ameliorates the LPS-inhibited osteogenic differentiation in preosteoblast MC3T3-E1 cells
miR-23b targets Smad 3 and ameliorates the LPS-inhibited osteogenic differentiation in preosteoblast MC3T3-E1 cells
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DOI：
10.2131/jts.41.185
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发表时间：
2016-04-01
影响因子：
2
通讯作者：
Su, Hao
中科院分区：
文献类型：
--
作者：
Liu, Hongzhi;Hao, Wei;Su, Hao
脂多糖(LPS)已被证实是成骨分化的主要抑制因子，对骨愈合提出了临床挑战，尤其是创伤后并发内毒素血症/脓毒症。然而，其分子机制仍不明确。在炎症中调节多个信号通路的MIR-23b已被证明被脂多糖解除调控。在本研究中，我们检测了内毒素对成骨前细胞MC3T3-E1中miR-23b和Smad3表达的调节。检测miR-23b过表达对Smad3表达的调节以及内毒素对骨形态发生蛋白-2(BMP-2)诱导的成骨分化的抑制作用。结果表明，内毒素可显著下调MC3T3-E1细胞miR-23b的表达，上调Smad3的表达。然而，miR-23b通过与Smad3的3‘-非翻译区(UTR)特异性结合，在mRNA和蛋白水平上均显著下调Smad3的表达。此外，尽管脂多糖通过抑制碱性磷酸酶(ALP)、骨钙素(OCN)、骨桥蛋白(OPN)和Runt相关转录因子2(RUNX2)的表达而显著下调BMP-2诱导的MC3T3-E1细胞的成骨分化。上调的miR-23b逆转了同时经脂多糖和BMP-2处理的MC3T3-E1细胞ALP、OCN、OPN和RUNX2的下调。综上所述，我们的研究结果表明miR-23b改善了内毒素对BMP-2诱导的MC3T3-E1细胞成骨分化的抑制作用，提示miR-23b在内毒素对成骨分化和骨形成的抑制中具有保护作用。
Lipopolysaccharide (LPS) has been confirmed to be the main inhibitor in osteogenic differentiation, posing a clinical challenge to bone healing, particularly for trauma followed by endotoxinemia/sepsis. However, the molecular mechanism remains ambiguous. miR-23b, which regulates multiple signaling pathways in inflammation, has been shown to be deregulated by LPS. In this study, we examined the LPS-mediated regulation on the expression of miR-23b and Smad 3 in preosteoblast MC3T3-E1 cells. Then we determined the regulation of miR-23b overexpression on the Smad 3 expression and on the LPS-mediated inhibition of bone morphogenetic protein-2 (BMP-2)-induced osteogenic differentiation. Our results demonstrated that LPS significantly downregulated the expression of miR-23b, while upregulating Smad 3 in MC3T3-E1 cells. However, the transfection with miR-23b mimics markedly downregulated the Smad 3 in both mRNA and protein levels, via the specific binding to the 3'-untranslated region (UTR) of Smad 3. Moreover, though LPS markedly downregulated the BMP-2-induced osteogenic differentiation of MC3T3-E1 cells by inhibiting the expression of alkaline phosphatase (ALP), Osteocalcin (OCN), Osteopontin (OPN) and Runt-related transcription factor 2 (RUNX2). The upregulated miR-23b reversed such downregulation of ALP, OCN, OPN and RUNX2 in the MC3T3-E1 cells which were treated both with LPS and BMP-2. In conclusion, our data indicates that miR-23b ameliorates the LPS-mediated inhibition of BMP-2-induced osteogenic differentiation in MC3T3-E1 cells, implying the protective role of miR-23b in the LPS-mediated inhibition of osteogenic differentiation and bone formation.