REGULATION OF CD154 EXPRESSION

CD154表达的调节

• 批准号: 6760227
• 负责人: WILLIAM FREDERICK CARSON RIGBY
• 金额: $ 34.48万
• 依托单位: DARTMOUTH COLLEGE
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6760227
• 关键词: CD40 molecule; RNA binding protein; RNA splicing; cell line; clinical research; genetic regulatory element; helper T lymphocyte; homopolynucleotide; human subject; immunoregulation; laboratory mouse; leukocyte activation /transformation; ligands; messenger RNA; nucleic acid metabolism; protein isoforms; pyrimidines

DESCRIPTION (provided by applicant): CD154 (CD40 ligand) expression by activated T cells plays a central role in the immune response. As such, CD154 expression has been implicated as a major target in the treatment of rheumatic diseases and validated by the demonstrated efficacy of CD154 blockade in animal models of Rheumatoid Arthritis and Systemic Lupus Erythematosus. Furthermore, CD154 gene expression is dysregulated in patients with Systemic Lupus Erythematosus. CD 154 (CD40 ligand) expression exhibits a unique pattern of regulation relative to cytokines. These studies have directly implicated CD154 mRNA degradation. We have established that a polypyrimidine-rich region in the 3'UTR of the CD154 mRNA is necessary and sufficient to reduce chimeric reporter gene expression in both cell lines and normal human CD4+ T lymphocytes, thus identifying this region as a cis-acting element. Furthermore, we have identified two proteins that bind to this polypyrimidine-rich region as distinct splice isoforms (PTB, PTB-T) of the PTB gene. This finding suggest that these proteins are trans-acting factors that determine the function of this region in mRNA decay. Overexpression of the novel smaller splice isoform we call PTB-T, consistently inhibits reporter gene expression in a CD154 3'UWR specific manner in normal human CD4+ T lymphocytes and cell lines. These data suggest the hypothesis that PTB-T interacts with the polypyrimidine-rich region in the CD154 3'UTR to mediate mRNA degradation. We propose to directly test this hypothesis as well as determine the biologic role of PTB-T in the modulation of CD154 mRNA stability. Subsequently, we will identify the pathway(s) by which PTB-T mediates these effects. In this manner, we will functionally delineate the molecular mechanism(s) which regulate CD154 mRNA turnover in vivo and determine their contribution to the unique pattern of CD154 gene regulation as well as the immune response. These studies will generate insights important for the development of approaches that will selectively modulate CD154 expression.

描述（由申请人提供）：激活的T细胞表达CD154（CD40配体）在免疫反应中起着核心作用。因此，CD154表达被认为是风湿性疾病治疗的主要靶点，并通过CD154阻滞在类风湿关节炎和全身性红斑狼疮的动物模型中证明的功效进行了验证。此外，全身性红斑狼疮患者的CD154基因表达失调。 CD 154（CD40配体）表达相对于细胞因子，表现出独特的调节模式。这些研究直接暗示了CD154 mRNA降解。我们已经确定，在CD154 mRNA的3'UTR中，富含息肉嘧啶的区域是必要且足够的，足以减少细胞系和正常人CD4+ T淋巴细胞中的嵌合报告基因表达，从而将该区域鉴定为顺式作用元件。此外，我们已经确定了两种与该息肉嘧啶富的区域结合的蛋白质是PTB基因的不同剪接同工型（PTB，PTB-T）。这一发现表明，这些蛋白质是决定该区域在mRNA衰变中功能的跨作用因素。新型较小的剪接同工型的过表达我们称为PTB-T，始终以正常的人CD4+ T淋巴细胞和细胞系以CD154 3'UWR特异性抑制报告基因表达。 这些数据表明，PTB-T与CD154 3'UTR中富含polypyrimidine的区域相互作用以介导mRNA降解。我们建议直接检验该假设，并确定PTB-T在CD154 mRNA稳定性调节中的生物学作用。随后，我们将确定PTB-T介导这些影响的途径。通过这种方式，我们将在功能上描述分子机制，该机制在体内调节CD154 mRNA转换，并确定它们对CD154基因调节独特模式以及免疫反应的贡献。这些研究将产生对开发将选择性调节CD154表达的方法重要的见解。