Gene Transcription In SLE

SLE 中的基因转录

• 批准号: 8207295
• 负责人: George C Tsokos
• 金额: $ 41.65万
• 依托单位: BETH ISRAEL DEACONESS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-04-15 至 2012-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8207295
• 关键词: Accounting; Age; Alternative Splicing; American; Autoantibodies; Autoantigens; Autoimmune Diseases; Autoimmunity; Binding; Biostatistics Core; CD3 Antigens; CD40 Ligand; CREM protein; Ca(2+)-Calmodulin Dependent Protein Kinase; Calcium; Cell Death; Cell Nucleus; Cell membrane; Cells; Collaborations; Cyclic AMP-Responsive DNA-Binding Protein; Data; Defect; Development; Disease; Etiology; Event; Exons; FOS Protein; FOS gene; Functional disorder; Gene Expression; Gene Targeting; Gene Transfer; Generations; Genetic Transcription; Histone Deacetylase; Histone Deacetylase Inhibitor; Histones; Human; Human Subject Research; IL2 gene; Immune; Immunology; Infection; Interleukin-2; Journals; Lead; Lupus; Manuscripts; Measures; Mediating; Membrane; Messenger RNA; Methods; Modification; Molecular; Molecular Target; Mus; Pathology; Patients; Pharmaceutical Preparations; Phosphorylation; Prevalence; Principal Investigator; Process; Production; Protein Binding; Proteins; Publishing; RNA Splicing; Recruitment Activity; Regulation; Regulatory T-Lymphocyte; Reporting; Repression; Role; Serum; Side; Signal Transduction; Site; Spleen; Systemic Lupus Erythematosus; T-Lymphocyte; Time; Transcription Repressor/Corepressor; Woman; autoreactive T cell; child bearing; computerized data processing; cytotoxic; human HDAC1 protein; improved; insight; lupus prone mice; novel; programs; promoter; public health relevance; research study; therapeutic target

DESCRIPTION (provided by applicant): Systemic lupus erythematosus (SLE) is an autoimmune disorder of largely unknown etiology characterized by profound T cell effector dysfunction. SLE T cells produced reduced amounts of interleukin 2 (IL-2) which contributes to the increased rate of infections, decreased generation of cytotoxic and regulatory T cells and decreased ability to eliminate autoreactive T cells through activation-induced cell death. IL-2 production is controlled at the transcription level by factors whose activity is influenced by membrane-initiated signaling events. We established that SLE T cells have increased protein and mRNA levels of the transcriptional repressor, cAMP responsive element modulator (CREM), which we found to bind to the -180 site of the IL-2 promoter and suppress IL-2 gene transcription. CREM also binds to the -57 site of the c-fos promoter which results in decreased expression of c-fos protein and activating protein-1 activity. Normal, unstimulated T cells do not express CREM, but after stimulation they display phosphorylated (p) cAMP responsive element binding protein (CREB) that binds also to the -180 site. We also demonstrated that anti-CD3/TCR autoantibodies activate calcium/calmodulin kinase IV (CaMKIV) which is found primarily in the nucleus where it phosphorylates CREM and histones. CREM recruits histone deacetylase 1 (HDAC1) to the promoters of the IL-2 and c-fos genes which contributes to the repression of their activity. Increased expression of CREM? in SLE T cells represents both increased promoter (newly characterized) activity and alternative splicing. It is hypothesized that cell membrane-initiated signaling processes lead to increased expression and activation of transcription repressors and modification of cellular proteins. We propose, accordingly, to a) establish that CaMKIV translocates to the nucleus of SLE T cells, determine how it becomes activated and whether its presence is crucial in the development of SLE in lupus prone mice; b) identify the functional repercussions of CREM? - mediated recruitment of HDAC1 to the regulation - of aberrant gene expression in SLE T cells, the identification of novel CREM target genes and whether its absence modifies the expression of SLE in lupus-prone mice; and c) determine mechanisms that result in increased production of CREM1 in SLE T cells, that is, increased promoter activity and enhanced alternative exon splicing process. The proposed studies will provide further insights into the molecular origin of defective IL-2 production in SLE patients and identify molecular targets that may be corrected with drugs or biologics. Successful completion will introduce additional mechanisms that lead to the generation of autoantigens that drive autoimmunity. PUBLIC HEALTH RELEVANCE - PROJECT NARRATIVE: Systemic lupus erythematosus (SLE) afflicts more than one million Americans most of whom are women in the child bearing age. Immune cells from patients with SLE produce decreased production of interleukin-2 and that leads to increased rate on infections and accounts for additional immunoregulatory defects. The proposed studies will explore the mechanisms that lead to decreased production of interleukin-2 in order to identify molecules that we can target for therapeutic purposes.

描述（由申请人提供）：全身性红斑狼疮（SLE）是一种自身免疫性障碍，其特征是以深度T细胞效应子功能障碍为特征。 SLE T细胞产生的白介素2（IL-2）的量减少，这有助于增加感染率，减少细胞毒性和调节性T细胞的产生，并通过激活诱导的细胞死亡消除自动反应性T细胞的能力降低。 IL-2的产生受到转录水平的控制，其活性受膜引起的信号事件影响。我们确定SLE T细胞的转录阻遏物，CAMP响应元件调节剂（CREM）的蛋白质和mRNA水平增加，我们发现它与IL-2启动子的-180位点结合并抑制IL-2基因转录。 CREM还与C-FOS启动子的-57位点结合，该位点导致C-FOS蛋白的表达降低和激活蛋白-1活性。正常，未刺激的T细胞不会表达CREM，但是在刺激后它们显示磷酸化（P）cAMP响应元件结合蛋白（CREB），该蛋白（CREB）也与-180位点结合。我们还证明了抗CD3/TCR自身抗体激活钙/钙调蛋白激酶IV（CAMKIV），该激酶IV（CAMKIV）主要在核中发现，它磷酸化CREM和组蛋白。 CREM将组蛋白脱乙酰基酶1（HDAC1）募集到IL-2和C-FOS基因的启动子，这有助于抑制其活性。 CREM表达增加？在SLE T细胞中，既代表启动子（新表征）活性增加，也代表了替代剪接。假设细胞膜引起的信号传导过程导致转录阻遏物的表达和激活增加和细胞蛋白的修饰。因此，我们建议a）确定CaMKIV易位到SLE T细胞的细胞核，确定其如何被激活，以及它的存在对于狼疮俯卧小鼠的SLE的发展至关重要。 b）确定CREM的功能影响吗？ - 将HDAC1介导的对SLE T细胞中异常基因表达的调节，新型CREM靶基因的鉴定以及其缺失是否会改变狼疮易发的小鼠SLE的表达； c）确定导致SLE T细胞中CREM1产生的机制，即启动子活性增加并增强替代外显子剪接过程。拟议的研究将为SLE患者中IL-2产生有缺陷的IL-2产生的分子起源提供进一步的见解，并确定可以用药物或生物制剂校正的分子靶标。成功完成将引入其他机制，从而导致自动免疫的自动抗原产生。 公共卫生相关性 - 项目叙事：系统性红斑狼疮（SLE）折磨了超过一百万美国人，其中大多数是孩子年龄的妇女。来自SLE患者的免疫细胞产生白介素2的产生降低，并导致感染率提高，并导致额外的免疫调节缺陷。拟议的研究将探讨导致白介素2产生降低的机制，以确定我们可以用于治疗目的的分子。