Epigenetic Control of Endothelial and T Cell States By BET Reader Proteins

BET Reader 蛋白对内皮细胞和 T 细胞状态的表观遗传控制

• 批准号: 9130373
• 负责人: JORGE PLUTZKY
• 金额: $ 42.9万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-08 至 2017-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9130373
• 关键词: Atherosclerosis; Autoimmune Process; BRD2 gene; Binding; Biology; Blood Vessels; Bromodomain; Cardiac; Cell Communication; Cell Culture Techniques; Cell Differentiation process; Cell Line; Cell physiology; Cells; Cellular biology; Chromatin; Clinical; Data; Disease model; Effector Cell; Endothelial Cells; Endothelium; Enhancers; Epigenetic Process; Excision; Exercise; Experimental Models; Family; Fostering; Gene Expression; Gene Targeting; Genes; Genetic Transcription; Genomics; Growth; Histones; Homeostasis; Human; IL17 gene; In Vitro; Inflammation; Inflammatory; Inflammatory Response; Interferon Type II; Investigation; Kinetics; Leukocytes; Lysine; Malignant Neoplasms; Mediating; Mediator of activation protein; Modeling; Mus; Myocardial Ischemia; Myocarditis; N-terminal; Nature; Nucleic Acid Regulatory Sequences; Pathologic; Physiological; Play; Process; Property; Protein Family; Proteins; Reader; Reading; Reperfusion Therapy; Reporting; Rest; Role; Sepsis; Signal Transduction; Stimulus; T cell differentiation; T cell response; T-Lymphocyte; Tail; Testing; Time; Tumor Necrosis Factor-alpha; Vascular Endothelial Growth Factors; Venous; Work; angiogenesis; cell type; cytokine; in vitro Model; in vivo; inhibitor/antagonist; insight; interest; macrophage; novel; programs; public health relevance; response

DESCRIPTION (provided by applicant): Endothelial cells (EC) must rapidly transition between distinct functional cell states - under basal conditions, where they help maintain homeostasis, and in response to inflammation, where they help coordinate systemic responses, like T cell recruitment. Such cell states are defined to a significant extent by the modulated, integrated expression of large, multiple gene transcriptional programs. The Bromodomain and Extra-Terminal (BET) family of bromodomain-containing epigenetic reader proteins (BRD2, BRD3, BRD4, collectively referred to here as BETs) orchestrate gene expression in response to specific stimuli by binding to specific acetylated lysines on N-terminal histone tails, fostering assembly of transcriptional machinery. Despite burgeoning interest in BETs and ongoing clinical BET inhibitor trials in humans, the role of BETs in ECs, T cells and EC-T cell interactions remains unexplored in terms of the endothelium and poorly understood in terms of T cell differentiation and function. We provide evidence here that BRD4 transduces the TNFα signal to endothelial chromatin, inducing coordinated genomic BRD4 redistribution to de novo super-enhancers that help drive transcription of the pro-inflammatory NFκB endothelial program. Moreover, these newly formed inflammatory regulatory regions accumulate at the expense of immediately decommissioned BRD4 super-enhancers previously active in quiescent ECs. Consistent with these findings, BET inhibition limits leukocyte responses to TNFα-activated ECs in vitro, ex vivo, and in vivo. This data frames our central hypothesis under study here: BET action and redeployment dynamically governs global transcriptional programs in ECs and T cells at rest and after inflammatory cytokine stimulation, thus controlling cell states and functional responses in inflammation and angiogenesis. Aim 1 will test the hypothesis that the demonstrated Brd4-controlled endothelial pro- inflammatory program varies as a function of the kinetics of BRD4-mediated responses, distinct EC types, induction of previously unrecognized TNFα/BRD4-controlled EC target genes, and the proximal cytokine stimulus. Aim 2 will test the hypothesis that BRD4 acts as a switch, controlling gene expression involved in basal EC function, and during angiogenesis under both physiologic (exercise) and pathologic (inflammatory angiogenesis in myocardial ischemia/reperfusion) conditions. Aim 3 will test the hypothesis that BETs modulate EC/T cell interactions and T effector cell differentiation through their control of transcription, limiting T cell-driven experimental autoimmune myocarditis (EAM). Together these studies will help define the role of BET epigenetic reader proteins as novel controllers of dynamic transcriptional programs in ECs, in T cells, and their interaction, yielding new insight into inflammation and angiogenesis.

描述（由申请人提供）：内皮细胞（EC）必须在不同的功能细胞状态之间快速转换-在基础条件下，它们有助于维持稳态，并响应炎症，它们有助于协调全身反应，如T细胞募集。这种细胞状态在很大程度上是由大的、多基因转录程序的调节的、整合的表达来定义的。含溴结构域的表观遗传阅读器蛋白（BRD 2、BRD 3、BRD 4，在此统称为BET）的溴结构域和末端外（BET）家族通过结合N末端组蛋白尾部上的特异性乙酰化赖氨酸，促进转录机制的组装，响应于特异性刺激而协调基因表达。尽管人们对BET的兴趣日益浓厚，并且正在进行人体临床BET抑制剂试验，但BET在EC、T细胞和EC-T细胞相互作用中的作用在内皮方面仍然未被探索，在T细胞分化和功能方面也知之甚少。我们提供的证据表明，BRD 4将TNFα信号转导至内皮染色质，诱导协调的基因组BRD 4重新分布至从头超级增强子，帮助驱动促炎性NFκB内皮程序的转录。此外，这些新形成的炎症调节区的积累是以先前在静止EC中活跃的BRD 4超级增强子立即退役为代价的。与这些发现一致，BET抑制限制了白细胞对 体外、离体和体内TNFα激活的EC。这些数据构成了我们在此研究的中心假设：BET作用和重新部署动态地控制静息和炎性细胞因子刺激后EC和T细胞中的全局转录程序，从而控制炎症和血管生成中的细胞状态和功能反应。目的1将检验以下假设：已证实的Brd 4控制的内皮促炎程序随BRD 4介导的应答动力学、不同EC类型、先前未识别的TNFα/BRD 4控制的EC靶基因的诱导和近端细胞因子刺激而变化。目的2将测试BRD 4作为开关的假设，其控制参与基础EC功能的基因表达，以及在生理（运动）和病理（心肌缺血/再灌注中的炎性血管生成）条件下的血管生成期间。目的3将验证BET通过其转录控制调节EC/T细胞相互作用和T效应细胞分化，限制T细胞驱动的实验性自身免疫性心肌炎（EAM）的假设。这些研究将有助于确定BET表观遗传阅读器蛋白作为EC、T细胞及其相互作用中动态转录程序的新型控制器的作用，从而对炎症和血管生成产生新的见解。