The role of BAF related complexes in regulatory T cell development and function

BAF 相关复合物在调节性 T 细胞发育和功能中的作用

• 批准号: 10176397
• 负责人: Diana Clare Hargreaves
• 金额: $ 79.28万
• 依托单位: SALK INSTITUTE FOR BIOLOGICAL STUDIES
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10176397
• 关键词: 3-Dimensional; Affect; Area; Autoimmune; Autoimmune Diseases; Autoimmunity; Binding; Binding Sites; Biochemical; Bioinformatics; Biology; Bromodomain; CRISPR/Cas technology; Cancer Model; Cell Lineage; Cells; ChIP-seq; Chemicals; Chromatin; Chromatin Remodeling Factor; Complex; DNA; Development; Disease Progression; Disease model; Drug usage; Epigenetic Process; Equilibrium; FOXP3 gene; Failure; Gene Expression; Genes; Genetic; Genetic Transcription; Genome; Goals; Hi-C; Homeostasis; Human; Immune response; Immune system; Immunosuppressive Agents; Impairment; Inflammatory; Insulin-Dependent Diabetes Mellitus; Knock-out; Knockout Mice; Knowledge; Lead; Link; Lymphoproliferative Disorders; Maintenance; Malignant Neoplasms; Modeling; Multiple Sclerosis; Mus; Ontology; Outcome; Outcomes Research; Play; Proteins; Regulation; Regulatory T-Lymphocyte; Research; Research Personnel; Rheumatoid Arthritis; Role; SMARCA4 gene; Screening Result; System; T-Cell Development; Testing; Transcriptional Regulation; anti-tumor immune response; conditional knockout; experimental study; genome-wide; immunopathology; improved; in vivo; inhibitor/antagonist; insight; loss of function mutation; melanoma; mouse model; novel; novel therapeutics; prevent; recruit; targeted treatment; transcription factor; transcriptome sequencing; tumor; tumor immunology

PROJECT SUMMARY Regulatory T cells (Treg) play a crucial role in keeping the immune system in balance and preventing autoimmune disease. Defective Treg function leads to autoimmune diseases including rheumatoid arthritis and multiple sclerosis. On the other hand, Treg cells inside tumors can block effective anti-tumor immune responses. The development and maintenance of the Treg cell lineage are dependent on the transcription factor Foxp3, as loss of function mutations lead to severe lymphoproliferative disease in mice and humans. Thus, understanding the mechanisms that govern Foxp3 induction and stability may lead to the development of novel therapies for autoimmune disease and cancer. Dr. Zheng and colleagues recently developed a system to perform genome- wide CRISPR/Cas9 knockout screens to identify Foxp3 regulators in mouse induced and natural Tregs. The unbiased screen results not only confirmed a number of known Foxp3 regulators but also revealed many novel factors that control Foxp3 expression. Gene ontology analysis of the newly identified Foxp3 regulators revealed significant enrichment of multiple genes encoding subunits of the BAF (SWI/SNF) chromatin remodeling complexes, indicating an unknown role for this regulator in Treg development. Among the three BAF related complexes, the newly described GBAF complex promotes the expression of Foxp3, whereas the PBAF complex represses its expression. Furthermore, deletion of the bromodomain-containing protein Brd9, specific to GBAF complexes, led to reduced Foxp3 expression and compromised Treg function. Additionally, bromodomain inhibitors and chemical degraders of BRD9 act similarly to Brd9 genetic deletion to impair Foxp3 expression and Treg suppressor function. RNA-seq and ChIP-seq studies suggest that Brd9 cooperates with Foxp3 to potentiate its binding to Foxp3 target genes and regulate their expression. The overall objective of this study is to define the role of BAF related complexes in Treg function through regulation of and cooperation with Foxp3. This goal will be accomplished by elucidating the role of G/PBAF in Foxp3 induction and maintenance (Aim 1), defining the biochemical association of G/PBAF complexes with Foxp3 (Aim 2), identifying the functional role of GBAF in Foxp3-dependent transcription (Aim 3), and characterizing the functional consequences of disrupting G/PBAF subunits in Tregs in autoimmune disease and cancer models (Aim 4). The outcomes of the proposed studies are expected to fundamentally advance the understanding of epigenetic control of Foxp3 gene expression and Treg transcriptional networks. Additionally, these studies will provide key insights into the function of the newly described GBAF complex and its relationship with PBAF complexes. Finally, the outcomes of this research could provide evidence to support using drugs to target BAF related complexes for the treatment of autoimmune diseases and cancer.

项目概要 调节性T细胞（Treg）在保持免疫系统平衡和预防疾病方面发挥着至关重要的作用。 自身免疫性疾病。 Treg 功能缺陷会导致自身免疫性疾病，包括类风湿性关节炎和 多发性硬化症。另一方面，肿瘤内的Treg细胞可以阻断有效的抗肿瘤免疫反应。 Treg 细胞谱系的发育和维持依赖于转录因子 Foxp3，如 功能丧失突变会导致小鼠和人类严重的淋巴增殖性疾病。因此，了解 控制 Foxp3 诱导和稳定性的机制可能会导致新疗法的开发 自身免疫性疾病和癌症。郑博士和同事最近开发了一种系统来执行基因组分析 广泛的 CRISPR/Cas9 敲除筛选，以鉴定小鼠诱导的和天然 Tregs 中的 Foxp3 调节因子。这 公正的筛选结果不仅证实了一些已知的 Foxp3 调节因子，而且还揭示了许多新颖的 控制 Foxp3 表达的因素。新发现的 Foxp3 调节因子的基因本体分析揭示 编码 BAF (SWI/SNF) 染色质重塑亚基的多个基因显着富集 复合物，表明该调节剂在 Treg 发育中的作用未知。三个BAF相关的 复合物中，新描述的 GBAF 复合物促进 Foxp3 的表达，而 PBAF 复合物 抑制其表达。此外，删除了 GBAF 特有的含溴结构域蛋白 Brd9 复合物，导致 Foxp3 表达减少并损害 Treg 功能。此外，溴结构域 BRD9 抑制剂和化学降解剂的作用与 Brd9 基因缺失类似，可损害 Foxp3 表达和 Treg 抑制功能。 RNA-seq 和 ChIP-seq 研究表明 Brd9 与 Foxp3 合作增强 它与 Foxp3 靶基因结合并调节其表达。本研究的总体目标是定义 BAF 相关复合物通过调节 Foxp3 并与其合作在 Treg 功能中发挥作用。这个目标 将通过阐明 G/PBAF 在 Foxp3 诱导和维持中的作用来完成（目标 1），定义 G/PBAF 复合物与 Foxp3 的生化关联（目标 2），确定 GBAF 在 Foxp3 依赖性转录（目标 3），并表征破坏 G/PBAF 的功能后果 自身免疫性疾病和癌症模型中 Tregs 的亚基（目标 4）。拟议研究的结果 预计将从根本上推进对 Foxp3 基因表达的表观遗传控制的理解 Treg 转录网络。此外，这些研究将为新的功能提供重要的见解。 描述了 GBAF 复合体及其与 PBAF 复合体的关系。最后，这项研究的结果可以 提供证据支持使用靶向 BAF 相关复合物的药物治疗自身免疫性疾病 疾病和癌症。