Regulation of medullary thymic epithelial cells and thymic central tolerance by Ikaros

Ikaros 对胸腺髓质上皮细胞和胸腺中枢耐受的调节

基本信息

批准号：
10586955
负责人：
Michael R Waterfield
金额：
$ 67.08万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-12-12 至 2027-11-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10586955
关键词：
Adult Affect Antigens Apoptosis Autoantigens Autoimmune Autoimmune Diseases Autoimmunity B-Lymphocytes Biological Biological Models Cell Line Cell Lineage Cell Ontogeny Cell physiology Cells Chromatin Clinical Complex Data Defect Developed Countries Development Education Ensure Epithelial Cell Proliferation Epithelium Family Flow Cytometry Gene Expression Gene Expression Profiling Genes Genetic Genetic Transcription Goals Growth Health Hematopoiesis Hematopoietic Heterogeneity Homeostasis Human Immune Immune Tolerance Immune system In Vitro Knowledge Link Lymphocyte Malignant Neoplasms Mediating Modeling Molecular Mus Mutate Mutation Patients Phenotype Play Population Positioning Attribute Process Regulation Reporter Reporting Role Sampling Self Tolerance Site Structure of thymic medulla T-Lymphocyte Technology Testing Thymic epithelial cell Thymus Gland Tissues Transcriptional Regulation Variant Work Zinc Fingers autoreactive T cell central tolerance fetal gene expression database immune self tolerance improved in vivo inducible Cre insight mouse model multiple omics mutant mouse model novel prevent progenitor programs single-cell RNA sequencing tool transcription factor

项目摘要

Project Summary A normal and robust immune system relies on the development of cells with diverse repertoire of antigen recognition but that remain tolerant of self-tissues. Breakdown of this immune tolerance can give rise to autoimmune disease, and hence multiple mechanisms are in place to ensure immune self-tolerance. The thymus is a critical site for the development and education of T cells to promote tolerance to self through expression of tissue specific antigens (TSAs) by specialized medullary thymic epithelial cells (mTECs). The transcriptional regulators Aire and Fezf2 are known to act within mTECs to promote the expression of thousands of TSA self- antigens for the purpose of removing developing self-reactive T cells in a process known as negative selection. Aire and Fezf2 are shown to be required for some, but not all TSA genes expressed in mTECs, suggesting additional transcriptional regulators are required for the full repertoire of the observed TSA expression in mTECs. Furthermore, recent work has highlighted the complexity of mTECs with at least four mTEC populations: Aire+ mTECs, Ccl21a mTECs, Late/Post Aire mTECs, and tuft cells. However, there is limited knowledge about the developmental regulation and progenitors of these heterogeneous mTEC subsets. We have identified the transcription factor Ikaros (Ikzf1) as a novel regulator of mTEC composition and function, with deletion of Ikaros in mTECs causing a reduction of Aire+ mTECs and an expansion of tuft cells. Moreover, Ikaros-deficient mTECs have a defect in TSA gene expression resulting in specific signs of autoimmunity. Interestingly, mutations in IKZF1 have been linked to human autoimmune diseases. Thus, we hypothesize a novel role for Ikaros in mTEC lineage development, TSA expression and central tolerance, and that defects in mTEC function could contribute to the autoimmunity seen in humans with IKZF1 mutations. We propose to test our hypothesis and increase our knowledge of this novel mTEC transcriptional regulator through the following specific aims: (1) Identify the stage(s) of mTEC development at which Ikaros modulates mTEC function, (2) Interrogate the molecular mechanism of Ikaros function in mTECs, and (3) Determine if TEC specific deletion of Ikaros affects T cell tolerance and autoimmunity. To complete these aims, we have developed a unique and powerful set of genetic tools and mouse reporter lines that allow us to perturb Ikaros function in mTECs. We will use flow cytometry to investigate mTEC and thymic immune cell phenotypes, combined scRNA-seq/scATAC-seq to analyze gene expression and chromatin accessibility, and supplement with mechanistic studies in vitro in cell lines. Our long-term goal is to increase our understanding of the regulation of mTEC development and function in central tolerance, and how alterations can lead to a break of tolerance and autoimmunity.

项目摘要一种正常且健壮的免疫系统依赖于具有抗原多样的细胞的发展认可，但仍然可以宽容自我组织。这种免疫耐受性的崩溃会引起自身免疫性疾病，因此有多种机制来确保免疫自我耐受。胸腺是T细胞开发和教育以通过表达来促进自我宽容的关键场所专门的髓质胸腺上皮细胞（MTEC）的组织特异性抗原（TSA）。转录已知监管机构AIRE和FEZF2在MTEC中起作用，以促进数千个TSA自我的表达抗原是为了在称为阴性选择的过程中去除开发自反应T细胞的目的。某些AIRE和FEZF2对于某些人来说是必需的，但并非所有在MTEC中表达的TSA基因，这表明需要其他转录调节剂才能在MTEC中观察到的TSA表达的完整曲目。此外，最近的工作强调了MTEC与至少四个MTEC人群的复杂性：AIRE+ MTEC，CCL21A MTEC，晚/后AIRE MTEC和簇细胞。但是，关于这些异质MTEC子集的发育调节和祖细胞。我们已经确定了转录因子Ikaros（IKZF1）是MTEC组成和功能的新型调节剂，并删除了Ikaros 在MTEC中，导致AIRE+ MTEC的减少和簇细胞的膨胀。此外，Ikaros缺陷MTEC 具有TSA基因表达缺陷，导致自身免疫的特定迹象。有趣的是，突变中的突变 IKZF1与人类自身免疫性疾病有关。因此，我们假设Ikaros在 MTEC谱系发展，TSA表达和中央公差以及MTEC功能的缺陷可以有助于在具有IKZF1突变的人类中看到的自身免疫性。我们建议检验我们的假设和通过以下特定目的增加我们对这一新型MTEC转录调节剂的了解：（1）确定IKAROS调节MTEC功能的MTEC开发阶段，（2）询问该功能 Ikaros在MTEC中的分子机制，（3）确定ikaros的特异性缺失是否影响 T细胞的耐受性和自身免疫性。为了完成这些目标，我们开发了一套独特而强大的集合遗传工具和小鼠记者线，使我们能够在MTEC中扰动Ikaros功能。我们将使用流研究MTEC和胸腺免疫细胞表型，结合SCRNA-SEQ/SCATAC-SEQ至分析基因表达和染色质的可及性，并补充细胞中的机理研究线。我们的长期目标是提高我们对MTEC开发和功能调节的理解在中央耐受性以及改变如何导致耐受性和自身免疫性的破坏。