Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
Department of Medical Oncology, Dana Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA.
Mol Cell. 2014 Oct 23;56(2):219-231. doi: 10.1016/j.molcel.2014.08.024. Epub 2014 Sep 25.
Proinflammatory stimuli elicit rapid transcriptional responses via transduced signals to master regulatory transcription factors. To explore the role of chromatin-dependent signal transduction in the atherogenic inflammatory response, we characterized the dynamics, structure, and function of regulatory elements in the activated endothelial cell epigenome. Stimulation with tumor necrosis factor alpha prompted a dramatic and rapid global redistribution of chromatin activators to massive de novo clustered enhancer domains. Inflammatory super enhancers formed by nuclear factor-kappa B accumulate at the expense of immediately decommissioned, basal endothelial super enhancers, despite persistent histone hyperacetylation. Mass action of enhancer factor redistribution causes momentous swings in transcriptional initiation and elongation. A chemical genetic approach reveals a requirement for BET bromodomains in communicating enhancer remodeling to RNA Polymerase II and orchestrating the transition to the inflammatory cell state, demonstrated in activated endothelium and macrophages. BET bromodomain inhibition abrogates super enhancer-mediated inflammatory transcription, atherogenic endothelial responses, and atherosclerosis in vivo.
促炎刺激通过转导信号引发快速转录反应,从而调控转录因子。为了探究染色质依赖信号转导在动脉粥样硬化炎症反应中的作用,我们对激活的内皮细胞表观基因组中的调控元件的动态、结构和功能进行了描述。肿瘤坏死因子-α的刺激促使染色质激活剂迅速而显著地向大量新形成的簇状增强子域重新分布。尽管组蛋白乙酰化持续存在,但核因子-κB 形成的炎症超级增强子会以牺牲立即停用的基础内皮超级增强子为代价而积累。增强子因子重新分布的大量作用导致转录起始和延伸发生重大波动。化学遗传方法揭示 BET 溴结构域在将增强子重塑传递给 RNA 聚合酶 II 以及协调向炎症细胞状态的转变中的重要性,这在激活的内皮细胞和巨噬细胞中得到了证明。BET 溴结构域抑制可消除超级增强子介导的炎症转录、动脉粥样硬化性内皮反应和体内动脉粥样硬化。