Setd7 and its contribution to Boron-induced bone regeneration in Boron-mesoporous bioactive glass scaffolds
Setd7 and its contribution to Boron-induced bone regeneration in Boron-mesoporous bioactive glass scaffolds
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Setd7及其对硼介孔生物活性玻璃支架中硼诱导骨再生的贡献
DOI：
10.1016/j.actbio.2018.04.033
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发表时间：
2018-06-01
影响因子：
9.7
通讯作者：
Li, Zubing
中科院分区：
文献类型：
--
作者：
Yin, Chengcheng;Jia, Xiaoshi;Li, Zubing
硼(B)是人体内发现的一种微量元素，通过促进成骨细胞的增殖和分化，对骨骼的健康起着重要的作用。本课题组先前制备的B介孔生物活性玻璃(MBG)支架与不含硼的纯MBG支架相比，成功地促进了成骨细胞的成骨分化。然而，B-MBG支架对成骨的积极作用机制尚不清楚。因此，我们用纯MBG支架在OVX大鼠模型上进行了体内实验，并与B-MBG支架进行了比较。结果发现，与纯MBG支架相比，B-MBG支架诱导了更多的新骨再生，并通过RNA-SEQ检测了B-MBG支架诱导骨再生的相关基因，以获得目的基因和表观遗传学机制。结果表明，与MBG组相比，B-MBG组Setd7的表达和从属关系增加。我们体内样本的免疫荧光染色进一步表明，在B-MBG支架处理的缺陷中，Setd7和H3K4me3在Runx2阳性细胞中有更高的定位。KEGG结果表明，在与B-MBG支架相关的新骨区域，Wnt/I3-catenin信号通路被高度激活。此后，在用B-MBG支架提取液刺激的人骨髓干细胞(HBMSCs)的体外研究中，与单独使用MBG支架相比，Setd7和H3K4me3的水平显著升高。为了验证在含硼条件下Setd7在新骨形成中的作用，用B-MBG或MBG支架的提取液刺激hBMSCs中的Setd7。结果显示，当Setd7被击倒时，hBMSCs的成骨细胞分化受到抑制，而B-MBG支架提取液不能挽救其成骨细胞分化和骨再生的作用。作为一种组蛋白甲基酶，Setd7有望成为新的骨质疏松治疗方案的表观遗传学靶点。本课题组已证实含硼MBG支架可促进去卵巢大鼠股骨缺损处的骨再生，但其促进骨生成的表观遗传学机制尚不清楚。在我们目前的研究中，我们发现在体内Runx2阳性的成骨细胞中Setd7和H3K4me3的表达和结合增加。在体外，与MBG支架相比，B-MBG支架提取液刺激的人BMSCs成骨分化能力增强，这可能与激活Wnt/β-catenin信号通路有关。总之，这提示Setd7在成骨分化中起积极作用，并可能成为治疗骨质疏松症新方案的潜在表观遗传学靶点。(C)2018 Acta Materialia Inc.由Elsevier Ltd.出版。保留所有权利。
Boron (B), a trace element found in the human body, plays an important role for health of bone by promoting the proliferation and differentiation of osteoblasts. Our research group previously fabricated B-mesoporous bioactive glass (MBG) scaffolds, which successfully promoted osteogenic differentiation of osteoblasts when compared to pure MBG scaffolds without boron. However, the mechanisms of the positive effect of B-MBG scaffolds on osteogenesis remain unknown. Therefore, we performed in-vivo experiments in OVX rat models with pure MBG scaffolds and compared them to B-MBG scaffold. As a result, we found that B-MBG scaffold induced more new bone regeneration compared to pure MBG scaffold and examined genes related to bone regeneration induced by B-MBG scaffold through RNA-seq to obtain target genes and epigenetic mechanisms. The results demonstrated an increased expression and affiliation of Setd7 in the B-MBG group when compared to the MBG group. Immunofluorescent staining from our in vivo samples further demonstrated a higher localization of Setd7 and H3K4me3 in Runx2-positive cells in defects treated with B-MBG scaffolds. KEGG results suggested that specifically Wnt/I3-catenin signaling pathway was highly activated in new bone area associated with B-MBG scaffolds. Thereafter, in vitro studies with human bone marrow stem cells (hBMSCs) stimulated by extracted liquid of B-MBG scaffolds was associated with significantly elevated levels of Setd7, as well as H3K4me3 when compared to MBG scaffolds alone. To verify the role of Setd7 in new bone formation in the presence of Boron, Setd7 was knocked down in hBMSCs with stimulation of the extracted liquids of B-MBG or MBG scaffolds. The result showed that osteoblast differentiation of hBMSCs was inhibited when Setd7 was knocked down, which could not be rescued by the extracted liquids of B-MBG scaffolds confirming its role in osteoblast differentiation and bone regeneration. As a histone methylase, Setd7 may be expected to be a potential epigenetic target for new treatment schemes of osteoporosis.Statement of SignificanceBoron-containing MBG scaffold has already been proved to promote bone regeneration in femoral defects of OVX rats by our research group, however, the epigenetic mechanism of Boron's positive effects on bone generation remains ill-informed. In our present study, we found an increased expression and affiliation of Setd7 and H3K4me3 in Runx2-positive osteoblasts in vivo. And in vitro, the higher expression of Setd7 enhanced osteogenic differentiation of human BMSCs stimulated by extracted liquids of B-MBG scaffold compared to MBG scaffold, which was associated with the activation of Wnt/beta-catenin signaling pathway. Above all, it suggests that Setd7 plays an positive role in osteogenic differentiation and it may become a potential epigenetic target for new schemes for osteoporosis. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.