The Role of miR-17~92 in Autoimmune Diseases

miR-17~92在自身免疫性疾病中的作用

• 批准号: 8260302
• 负责人: Changchun Xiao
• 金额: $ 42.3万
• 依托单位: SCRIPPS RESEARCH INSTITUTE, THE
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-15 至 2015-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8260302
• 关键词: Apoptosis; Applications Grants; Autoimmune Diseases; Autoimmunity; B-Lymphocytes; Bioinformatics; Biological; Biological Process; Biology; Bone Marrow; CD19 gene; Cell Differentiation process; Cells; Clonal Deletion; Code; Communities; Development; Diagnostic; Disease; Down-Regulation; Epigenetic Process; Exhibits; Future; Gene Amplification; Gene Targeting; Genes; Genetic; Genomics; Goals; Human; Immune Tolerance; Immune response; Immune system; Immunoprecipitation; Individual; Light; Lymphocyte; Lymphoma; Lymphomagenesis; Lymphoproliferative Disorders; Malignant Neoplasms; Mammalian Cell; Mammals; Mediating; Messenger RNA; Methods; MicroRNAs; Modeling; Molecular; Monitor; Mus; Mutation; Outcome; Pathway interactions; Patients; Pattern; Pilot Projects; Play; Production; Proteins; Proteomics; Publishing; RNA Sequences; Repression; Research; Role; Subfamily lentivirinae; Superantigens; T-Lymphocyte; Technology; Therapeutic Intervention; Transgenes; Transgenic Mice; Transgenic Model; Transgenic Organisms; Translational Repression; Translations; Untranslated Regions; Work; anergy; anti-IgM; cohort; crosslink; human disease; innovation; insight; mRNA Decay; mouse development; mouse model; protein expression; public health relevance; receptor; recombinase; reconstitution; research study; therapeutic target

DESCRIPTION (provided by applicant): MicroRNAs (miRNAs) have recently emerged as a major class of trans-factors that regulate expression of protein coding genes through their 3'UTRs, thereby controlling a diverse range of biological processes including cell differentiation, proliferation, and apoptosis. miRNAs pair with mRNAs of their target genes and the usual consequence is the downregulation of protein expression by translational repression, mRNA cleavage, or promotion of mRNA decay. Hundreds of miRNAs, many of them evolutionarily conserved, have been identified in mammals, and a fraction of these molecules exhibit highly specific, regulated expression patterns in the immune system. Genetic studies from us and other groups have demonstrated that miRNAs play critical roles in lymphocyte development, immune responses, and lymphomagenesis. However, little is known about the roles of miRNAs in autoimmune diseases. A large amount of genetic and epigenetic alterations in miRNA coding genes have been found in human patients. Among them is the amplification of the miR-17~92 gene, which encodes six distinct miRNAs, and the elevated expression of miR-17~92 miRNAs in cells carrying this gene amplification. We have generated a miR-17~92 transgene whose expression can be turned on conditionally by Cre recombinase in mice. Strikingly, the transgenic mice developed a lymphoproliferative and autoimmune disease, and died prematurely, when this transgene was turned on in both B and T lymphocytes using hCD2-iCre. Our preliminary studies showed that transgenic miR-17 ~ 92 expressions broke B cell tolerance in an anti-IgM macroself (5b-ms) superantigen transgenic model. We hypothesize that transgenic miR-17~92 expression causes autoimmune diseases mainly by breaking B cell tolerance. We now propose studies to elucidate the cellular and molecular mechanisms underlying miR-17~92 mediated breaking of B cell tolerance and development of autoimmune diseases, and to illustrate how alterations in miRNA expression contribute to autoimmunity and how miRNA clusters carry out their functions. We will determine the contribution of transgenic miR-17~92 expression in B cells to the autoimmune disease (Aim 1), assess the impact of transgenic miR-17~92 expression on B cell tolerance checkpoints (Aim 2), dissect the functional contribution of individual miRNAs in the miR-17~92 cluster to the breaking of B cell tolerance (Aim 3), and identify target genes and molecular pathways whose deregulation leads to the autoimmune disease in miR-17~92 transgenic mice (Aim 4). We will combine genetic, proteomic, genomic, molecular, and bioinformatic approaches to achieve these goals. PUBLIC HEALTH RELEVANCE: The proposed study will shed light on the ways by which alterations in miRNA expression contribute to autoimmunity. Once the causative relationship between miRNA deregulation and human autoimmune diseases has been established, those miRNAs themselves can become valuable diagnostic markers and possible targets of therapeutics. Furthermore, miRNA target genes and the physical interactions between miRNAs and their key target mRNAs could make ideal targets for therapeutic interventions.

描述（由申请人提供）：微小RNA（miRNAs）最近已经作为一类主要的反式因子出现，其通过其3 'UTR调节蛋白质编码基因的表达，从而控制多种生物过程，包括细胞分化、增殖和凋亡。miRNA与其靶基因的mRNA配对，通常的结果是通过翻译抑制、mRNA切割或促进mRNA降解来下调蛋白质表达。已经在哺乳动物中鉴定了数百种miRNAs，其中许多是进化上保守的，并且这些分子中的一部分在免疫系统中表现出高度特异性的受调控的表达模式。我们和其他研究小组的遗传学研究表明，miRNA在淋巴细胞发育、免疫应答和淋巴瘤发生中起着关键作用。然而，关于miRNAs在自身免疫性疾病中的作用知之甚少。在人类患者中发现了大量的miRNA编码基因的遗传和表观遗传改变。其中之一是miR-17~92基因的扩增，该基因编码六种不同的miRNA，以及miR-17~92 miRNA在携带该基因扩增的细胞中的表达升高。我们成功地构建了一个miR-17~92转基因小鼠，其表达可被Cre重组酶有条件地开启。引人注目的是，当使用hCD 2-iCre在B和T淋巴细胞中开启该转基因时，转基因小鼠发展成淋巴增殖性和自身免疫性疾病，并且过早死亡。我们的初步研究表明，转基因miR-17 ~ 92的表达在抗IgM宏自身（5 b-ms）超抗原转基因模型中打破了B细胞耐受。我们推测转基因miR-17~92的表达主要通过破坏B细胞耐受性而导致自身免疫性疾病。本研究旨在阐明miR-17~92介导的B细胞耐受性破坏和自身免疫性疾病发生的细胞和分子机制，并阐明miRNA表达的改变如何促进自身免疫以及miRNA簇如何发挥其功能。我们将确定转基因miR-17~92在B细胞中表达对自身免疫性疾病的贡献（目的1），评估转基因miR-17~92表达对B细胞耐受检查点的影响（目的2），剖析miR-17~92簇中单个miRNA对破坏B细胞耐受的功能贡献（目的3），目的4：研究miR-17~92转基因小鼠自身免疫性疾病的靶基因和分子通路。我们将结合联合收割机遗传学，蛋白质组学，基因组学，分子和生物信息学的方法来实现这些目标。 公共卫生相关性：拟议的研究将阐明miRNA表达的改变有助于自身免疫的方式。一旦确定了miRNA失调与人类自身免疫性疾病之间的因果关系，这些miRNA本身就可以成为有价值的诊断标志物和可能的治疗靶点。此外，miRNA靶基因以及miRNA与其关键靶mRNA之间的物理相互作用可以成为治疗干预的理想靶标。