The role of FAST in immune-mediated inflammatory disease

描述（由申请人提供）： 本提案的目的是确定FAST（Fas激活的丝氨酸/苏氨酸磷蛋白）在免疫介导的炎症性疾病的发病机制中的作用。FAST在类风湿性关节炎和系统性红斑狼疮患者的外周血细胞中过表达。FAST与TIA-1结合，TIA-1是一种腺嘌呤/尿苷富集元件（ARE）结合蛋白，可抑制选定促炎蛋白（包括TNF、IL-1、考克斯-2和MMP-13）的翻译。我们表明，FAST可以抑制TIA-1介导的翻译沉默。FAST还抑制Fas诱导的细胞凋亡，可能是通过抑制TIA-1介导的编码细胞凋亡抑制剂的含ARE转录物的翻译沉默。我们假设FAST通过促进促炎蛋白的表达和抑制Fas诱导的细胞凋亡而参与免疫介导的炎症性疾病的发病机制。具体目标是：1）完成FAST：TIA-1复合物的结构：功能分析，2）确定FAST对促炎蛋白表达的影响，3）确定FAST如何调节细胞凋亡，和4）确定FAST是否调节转基因小鼠中免疫介导的炎性疾病。我们将确定FAST是否促进巨噬细胞中促炎蛋白的表达。我们将鉴定不能与TIA-1结合的FAST突变体，以确定TIA-1是否对该功能至关重要。我们将鉴定编码凋亡抑制剂的mRNA，这些抑制剂被FAST靶向以抑制Fas诱导的凋亡。我们将确定与TIA-1和BCL-XL的相互作用如何调节FAST的功能。最后，我们将产生过表达FAST的转基因小鼠和缺乏FAST的突变小鼠，以确定其在免疫介导的炎症性疾病的起始和/或传播中的重要性。

DESCRIPTION (provided by applicant): The objective of this proposal is to determine the role of FAST (Fas-activated serine/threonine phosphoprotein) in the pathogenesis of immune-mediated inflammatory disease. FAST is overexpressed in peripheral blood cells derived from patients with rheumatoid arthritis and systemic lupus erythematosus. FAST binds to TIA-1, an adenine/uridine-rich element (ARE)-binding protein that inhibits the translation of select pro-inflammatory proteins, including TNF, IL-1, COX-2 and MMP-13. We show that FAST can inhibit TIA-1 mediated translational silencing. FAST also inhibits Fas-induced apoptosis, probably by inhibiting TIA-1 mediated translational silencing of ARE-containing transcripts encoding inhibitors of apoptosis. We hypothesize that FAST contributes to the pathogenesis of immune-mediated inflammatory disease by promoting the expression of pro-inflammatory proteins and inhibiting Fas-induced apoptosis. The specific aims are: 1) To complete a structure:function analysis of the FAST:TIA-1 complex, 2) To determine the effect of FAST on the expression of pro-inflammatory proteins, 3) To determine how FAST regulates apoptosis, and 4) To determine whether FAST modulates immune-mediated inflammatory disease in transgenic mice. We will determine whether FAST promotes the expression of pro-inflammatory proteins in macrophages. We will identify FAST mutants that cannot bind to TIA-1 to determine whether TIA-1 is essential for this function. We will identify the mRNAs encoding inhibitors of apoptosis that are targeted by FAST to inhibit Fas-induced apoptosis. We will determine how interactions with TIA-1 and BCL-XL regulate the function of FAST. Finally, we will generate transgenic mice that overexpress FAST and mutant mice that lack FAST to determine its importance in the initiation and/or propagation of immune-mediated inflammatory disease.