Notch signaling represses hypoxia-inducible factor-1α-induced activation of Wnt/β-catenin signaling in osteoblasts under cobalt-mimicked hypoxia.
Notch signaling represses hypoxia-inducible factor-1α-induced activation of Wnt/β-catenin signaling in osteoblasts under cobalt-mimicked hypoxia.
复制标题
DOI：
10.3892/mmr.2016.5324
复制
发表时间：
2016-07
影响因子：
3.4
通讯作者：
Li SJ
中科院分区：
文献类型：
--
作者：
Li CT;Liu JX;Yu B;Liu R;Dong C;Li SJ
缺氧对 Wnt 和 Notch 信号通路的改变及其与成骨细胞增殖和凋亡的关系仍有待充分阐明。为了研究 Wnt-Notch 串扰及其在缺氧诱导的成骨细胞增殖和细胞凋亡调节中的作用，本研究研究了当使用 γ-分泌酶抑制剂 DAPT 抑制 Notch 信号时，模拟钴缺氧对小鼠前成骨细胞样细胞系 MC3T3-E1 的影响。数据显示，模拟钴缺氧在正常条件下抑制细胞增殖，但在Notch抑制条件下以浓度依赖性方式增加细胞增殖。蛋白质印迹和逆转录定量聚合酶链反应分析结果表明，在 DAPT 诱导的 Notch 抑制下，钴处理增加了活化 β-catenin 蛋白的水平以及靶基因轴抑制蛋白 2 和骨髓细胞瘤癌基因的表达水平。然而，Notch胞内结构域蛋白或Notch靶基因hes1的表达水平没有发现显着变化。在β-catenin基因敲低实验中，DAPT处理可降低MC3T3-E1细胞在缺氧条件下的增殖，敲低缺氧诱导因子-1α（HIF-1α）的表达可抑制钴诱导的Wnt靶基因水平的增加。当 HIF-1α 的表达被敲低时，DAPT 处理后的细胞增殖率没有发现显着差异。本研究结果表明，在模拟钴缺氧条件下，Wnt 和 Notch 信号传导存在相反的作用，而这种作用部分受到 HIF-1α 的调节，结果还表明，成骨细胞增殖依赖于 Wnt-Notch 信号串扰。
The modification of Wnt and Notch signaling pathways by hypoxia, and its association with osteoblast proliferation and apoptosis remain to be fully elucidated. To investigate Wnt-Notch crosstalk, and its role in hypoxia-induced osteoblast proliferation and apoptosis regulation, the present study investigated the effects of cobalt-mimicked hypoxia on the mouse pre-osteoblast-like cell line, MC3T3-E1, when the Notch signals were repressed using a γ-secretase inhibitor DAPT. The data showed that the cobalt-mimicked hypoxia suppressed cell proliferation under normal conditions, but increased cell proliferation under conditions of Notch repression, in a concentration-dependent manner. The results of western blot and reverse transcription-quantitative polymerase chain reaction analyses showed that the cobalt treatment increased the levels of activated β-catenin protein and the expression levels of the target genes, axis inhibition protein 2 and myelocytomatosis oncogene, under DAPT-induced Notch repression. However, no significant changes were found in the expression levels of the Notch intracellular domain protein or the Notch target gene, hes1. In a β-catenin gene-knockdown experiment, the proliferation of the MC3T3-E1 cells under hypoxia were decreased by DAPT treatment, and knockdown of the expression of hypoxia-inducible factor-1α (HIF-1α) suppressed the cobalt-induced increase in Wnt target gene levels. No significant difference in cell proliferation rate was found following DAPT treatment when the expression of HIF-1α was knocked down. The results of the present study showed the opposing effects of Wnt and Notch signaling under cobalt-mimicked hypoxia, which were partially regulated by HIF-1α, The results also showed that osteoblast proliferation was dependent on Wnt-Notch signal crosstalk.