Role of the DR/DQ super enhancer in MHC-II expression

DR/DQ 超级增强子在 MHC-II 表达中的作用

• 批准号: 10218017
• 负责人: JEREMY M. BOSS
• 金额: $ 48.01万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-16 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10218017
• 关键词: 3-Dimensional; ATAC-seq; Address; Affect; Allogenic; Antigen-Presenting Cells; Antigens; Architecture; Autoimmune Diseases; Autoimmunity; B cell differentiation; B-Cell Development; B-Lymphocytes; Binding; Binding Proteins; Biochemical; Bioinformatics; Biological Assay; CD4 Positive T Lymphocytes; CREB1 gene; CRISPR/Cas technology; Cells; Chromatin; Chromatin Loop; Chromatin Structure; Chromosome 6; Communicable Diseases; Complex; Data; Development; Disease; Elements; Enhancers; Future; Gene Expression; Gene Expression Regulation; Genes; Genetic Polymorphism; Genetic Transcription; Goals; HLA-DQA1; HLA-DR Antigens; HLA-DRB1; Helper-Inducer T-Lymphocyte; Human; Human Genome; Immune; Immune System Diseases; Immune response; Immune system; Immunity; Immunization; Immunotherapy; Individual; Infection; Insulator Elements; Knowledge; Link; Literature; MHC class II transactivator protein; Major Histocompatibility Complex; Malignant Neoplasms; Mediating; Messenger RNA; Modeling; Molecular; Nucleic Acid Regulatory Sequences; Peptides; Plasma Cells; Process; Promoter Regions; Property; Proteins; Regulation; Regulatory Element; Regulatory T-Lymphocyte; Reporter Genes; Research; Role; Science; Series; Structure; System; T cell response; T-Cell Activation; T-Lymphocyte; Technology; Testing; Therapeutic; Tissues; Transcriptional Regulation; Transplantation; Untranslated RNA; Vaccination; Variant; Work; adaptive immune response; adaptive immunity; base; cell type; chromatin remodeling; chromosome conformation capture; cohesin; cytokine; design; experimental study; gene function; histone modification; human disease; improved; infectious disease treatment; insight; novel; programs; promoter; recruit; stem; transcription factor; transcriptome sequencing

Major histocompatibility complex class-II (MHC-II) proteins are encoded by HLA-DR, -DQ, and -DP α/β gene pairs and function by presenting processed antigenic peptides to CD4+ T cells thereby initiating and/or sustaining adaptive immune responses. MHC-II expression is transcriptionally regulated and expressed constitutively in antigen-presenting cells, such as B cells, but may be induced in non-immune cells by IFNγ. Thus, MHC-II- mediated immune responses and adaptive immunity is controlled primarily at the level of transcription. All MHC- II genes are coregulated by a common set of proximal promoter transcription elements and factors of which only CIITA is cell type limiting and induced by IFNγ. Several years ago, we showed that MHC-II gene expression was also modulated by a series of transcriptional insulator elements that bound CTCF and cohesin and that these elements were the focal points of long-range chromatin interactions between each other and MHC-II promoter regions. Together these elements formed a three-dimensional chromatin architecture that favored gene expression. Indeed, as B cells differentiated into plasma cells and lost MHC-II expression, this architecture was also lost. While this model is correct and has stood for the last 5 years, we now provide exciting new evidence that it is incomplete. New data presented herein identifies a super enhancer (SE) located between the HLA- DRB1 and -DQA1 genes (termed the DR/DQ-SE) that is required for maximal expression of the system and for its “3D” architecture. CRISPR/Cas9 mediated deletion of the DR/DQ-SE in Raji B cells resulted in decreased expression of HLA-DR and -DQ, reduced ability to stimulate an allogenic CD4 T cell response, and loss of promoter associated histone modifications and all local CTCF-insulator interactions. Additionally, while it is accepted that MHC proteins are highly polymorphic, non-coding polymorphisms within cis-regulatory regions of the MHC-II locus are more extensive and strongly linked to MHC-II expression and disease, suggesting that transcriptional regulation of MHC-II expression by the DR/DQ-SE is a key component of immunity and disease. Aside from what we present, nothing else is known about this region and how it works. To fill this gap in knowledge, this application seeks to understand how this SE functions to control MHC-II expression and immunity. Aim 1 will elucidate fundamental molecular and biochemical components of the DR/DQ-SE and determine how polymorphisms affect its function. Aim 2 will determine the range of the SE’s influence and test a model of how it may operate. Aim 3 will examine how the SE is established, and decommissioned. Together, our studies will provide insight into how human (SNP) diversity influences immunity, and ultimately how this critically important set of immune system genes are regulated. The knowledge gained will have broad implications on gene regulation and will provide new insight into how the initial steps of adaptive immune responses may be controlled. Our results could have important implications for future immune-based therapies and vaccinations, and for treatments of infectious disease, autoimmunity, cancer, and transplantation.

主要的组织相容性复合物II类（MHC-II）蛋白由HLA-DR，-DQ和-DPα/β基因编码 通过向CD4+ T细胞呈现加工的抗原抗原的抗原，从而启动和/或持续来对和功能 自适应免疫调查。 MHC-II表达在转录中受到转录调节和组成型表达 抗原呈递细胞，例如B细胞，但可能会在非免疫细胞中由IFNγ诱导。那，MHC-II- 介导的免疫血液和适应性免疫复杂主要控制着转录水平。所有MHC- II基因由一组常见的代理启动子转录元件和仅因素组成 CIITA是细胞类型的限制，由IFNγ诱导。几年前，我们表明MHC-II基因表达是 还通过结合CTCF和粘着素的一系列转录绝缘子元件进行调节，这些元件 元素是彼此与MHC-II启动子之间远程染色质相互作用的焦点 地区。这些元素共同形成了一个三维染色质结构，有利于基因 表达。确实，当B细胞分化为浆细胞并丧失MHC-II表达时，该结构是 也失去了。虽然该模型是正确的，并且在过去的5年中停滞不前，但我们现在提供令人兴奋的新证据 这是不完整的。本文提供的新数据标识了位于HLA-之间的超级增强剂（SE） DRB1和-DQA1基因（称为DR/DQ -SE），这是系统和最大表达和用于系统所必需的 它的“ 3D”架构。 RASPR/CAS9介导的Raji B细胞中DR/DQ-SE的缺失导致精制 HLA -DR和-DQ的表达，降低刺激Altelgonic CD4 T细胞反应的能力，并丢失 启动子相关的组蛋白修饰和所有局部CTCF - 绝缘子相互作用。另外，虽然是 接受MHC蛋白是在顺式调节区域内高度多态性的非编码多态性 MHC-II基因座更广泛，与MHC-II的表达和疾病密切相关，这表明 DR/DQ-SE对MHC-II表达的转录调节是免疫和疾病的关键组成部分。 除了我们提出的内容外，对该地区及其工作原理一无所知。填补这个空白 知识，本应用程序试图了解该SE如何控制MHC-II表达和 免疫。 AIM 1将阐明DR/DQ-SE的基本分子和生化成分 确定多态性如何影响其功能。 AIM 2将确定SE的影响力和测试的范围 AIM 3将检查SE的建立方式和退役。一起， 我们的研究将提供有关人（SNP）多样性如何影响免疫学的洞察力，并最终如何影响免疫学 调节至关重要的免疫系统基因。获得的知识将有广泛的 对基因调节的含义，并将提供有关自适应免疫初始步骤的新见解 可以控制响应。我们的结果可能对未来基于免疫的疗法具有重要意义 和疫苗接种，以及用于传染病，自身免疫，癌症和移植的治疗。