Histone demethylase KDM5A is transactivated by the transcription factor C/EBP and promotes preadipocyte differentiation by inhibiting Wnt/-catenin signaling
Histone demethylase KDM5A is transactivated by the transcription factor C/EBP and promotes preadipocyte differentiation by inhibiting Wnt/-catenin signaling
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组蛋白去甲基化酶 KDM5A 被转录因子 C/EBP 反式激活，并通过抑制 Wnt/-catenin 信号传导促进前脂肪细胞分化
DOI：
10.1074/jbc.ra119.008419
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发表时间：
2019-06-14
影响因子：
4.8
通讯作者：
Tang, Qi-Qun
中科院分区：
文献类型：
--
作者：
Guo, Liang;Guo, Ying-Ying;Tang, Qi-Qun
β-连环蛋白信号传导由WNT蛋白触发，并且是负调节脂肪形成的重要途径。然而，在脂肪形成过程中控制WNT蛋白表达的机制仍不完全清楚。赖氨酸脱甲基酶5A（KDM 5A）是一种组蛋白脱甲基酶，其从组蛋白3（H3 K4）的赖氨酸4（Lysine 4）去除三甲基（me 3）标记，并且充当一般转录辅阻遏物。在这里，使用小鼠3 T3-L1前脂肪细胞分化模型和一系列生化方法，包括ChIP，免疫沉淀，RT-qPCR和免疫印迹分析，我们表明，Kdm 5a是CCAAT/增强子结合蛋白（C/EBP），脂肪形成所需的一个重要的早期转录因子的靶基因。我们发现C/EBP结合到Kdm 5a基因启动子并反式激活其表达。我们还发现siRNA介导的KDM 5A下调抑制3 T3-L1前脂肪细胞分化。KDM 5A敲低显著上调脂肪形成Wnt 6的负调节因子，在其启动子上具有增加的H3 K4 me 3标记水平。我们进一步观察到WNT 6敲低显著挽救了被KDM 5A敲低抑制的脂肪形成。此外，我们注意到C/EBP通过与Wnt 6基因启动子结合并抑制Wnt 6转录来负调控Wnt 6表达。进一步的实验表明，KDM 5A与C/EBP相互作用，并且它们的相互作用协同抑制Wnt 6转录。值得注意的是，C/EBP敲低损害了KDM 5A向Wnt 6启动子的募集，Wnt 6启动子具有更高的H3 K4 me 3水平。我们的研究结果表明，在3 T3-L1前脂肪细胞分化过程中，涉及C/EBP和KDM 5A活性的机制下调Wnt/-catenin通路。
beta-Catenin signaling is triggered by WNT proteins and is an important pathway that negatively regulates adipogenesis. However, the mechanisms controlling the expression of WNT proteins during adipogenesis remain incompletely understood. Lysine demethylase 5A (KDM5A) is a histone demethylase that removes trimethyl (me3) marks from lysine 4 of histone 3 (H3K4) and serves as a general transcriptional corepressor. Here, using the murine 3T3-L1 preadipocyte differentiation model and an array of biochemical approaches, including ChIP, immunoprecipitation, RT-qPCR, and immunoblotting assays, we show that Kdm5a is a target gene of CCAAT/enhancer-binding protein (C/EBP), an important early transcription factor required for adipogenesis. We found that C/EBP binds to the Kdm5a gene promoter and transactivates its expression. We also found that siRNA-mediated KDM5A down-regulation inhibits 3T3-L1 preadipocyte differentiation. The KDM5A knockdown significantly up-regulates the negative regulator of adipogenesis Wnt6, having increased levels of the H3K4me3 mark on its promoter. We further observed that WNT6 knockdown significantly rescues adipogenesis inhibited by the KDM5A knockdown. Moreover, we noted that C/EBP negatively regulates Wnt6 expression by binding to the Wnt6 gene promoter and repressing Wnt6 transcription. Further experiments indicated that KDM5A interacts with C/EBP and that their interaction cooperatively inhibits Wnt6 transcription. Of note, C/EBP knockdown impaired the recruitment of KDM5A to the Wnt6 promoter, which had higher H3K4me3 levels. Our results suggest a mechanism involving C/EBP and KDM5A activities that down-regulates the Wnt/-catenin pathway during 3T3-L1 preadipocyte differentiation.