Autoimmunity in IEX-1- transgenic mice

IEX-1 转基因小鼠的自身免疫

• 批准号: 6872468
• 负责人: Mei X Wu
• 金额: $ 33.9万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-04-01 至 2007-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6872468
• 关键词: I kappa B beta; Retroviridae; T cell receptor; T lymphocyte; antisense nucleic acid; apoptosis; autoimmunity; genetic regulation; genetically modified animals; inflammation; laboratory mouse; polymerase chain reaction; regulatory gene; site directed mutagenesis; transfection

DESCRIPTION (provided by applicant): Activation-induced cell death (AICD) is one of the major mechanisms to eliminate unwanted and activated lymphocytes during the end of immune response to maintain lymphocyte homeostasis. The overall aim of this proposal is to understand the molecular basis whereby T cells resist to AICD during a clonal expansion phase of an immune response, but gradually become susceptible to it toward the end of the immune response. Work from several laboratories has clearly shown a prominent role for NF-kappaB/rel protein activation in promoting cell survival. We previously identified one such NF-kappaB/rel-regulated anti-apoptotic gene IEX-1 L, an unspliced variant of IEX-1 (Immediate Early responsive gene X-1). Our more recent data using IEX-1-transgenic (Tg.) mice demonstrate that IEX-1, similar to IEX-1 L, also protects T cells from AICD both in vitro and in vivo. Constitutive expression of IEX-1 in lymphocytes results in the accumulation of memory/effector-like T cells in the spleen and lymph node and increased susceptibility to a lupus-like autoimmune disease, clearly suggesting a role for IEX-1 in the survival of responding T cells. Consistent with its anti-death activity, IEX-1 is recently found to potentially bind to Bcl-xL and metallothionein (MT), a cysteine -rich molecule that scavenges hydroxyl radical. We hypothesize that high levels of IEX-1 expression during the early phase of T cell activation protect T cells from apoptosis, whereas decreased expression of IEX-1 renders them susceptible to AICD at the end of immune responses. To test this, we will use anti-sense IEX-1-containing retrovirus to inhibit IEX-1 expression, sensitizing activated T cells to apoptosis. We will also examine IEX-1 expression in antigen (Ag)-stimulated T cells in the setting of inflammation to establish a physiological relevance of our observations with IEX-1-Tg. mice. Aim 2 will determine in vivo and in vitro effects of IEX-1 on the life span of Ag-stimulated T cells with or without expressing a truncated IkBa (N) by crossbreeding T cell receptor/IEX-l-Tg mice with IkBa (N)- mice. Finally, aim 3 will verify the interactions of IEX-1 with Bcl-xL and/or MT proteins through various biochemical approaches and correlate the interactions to the anti-death activity of IEX-1. These studies will underscore the role of IEX-1 in the regulation of T cell homeostasis and potentially identify novel targets for therapeutic intervention in autoimmune diseases.

描述（由申请人提供）：激活诱导的细胞死亡（AICD）是在免疫反应结束期间消除不需要的和激活的淋巴细胞以维持淋巴细胞稳态的主要机制之一。该提案的总体目标是了解 T 细胞在免疫反应的克隆扩增阶段抵抗 AICD 的分子基础，但在免疫反应结束时逐渐变得对其敏感。多个实验室的工作清楚地表明 NF-kappaB/rel 蛋白激活在促进细胞存活中发挥着重要作用。我们之前鉴定了一个这样的 NF-kappaB/rel 调节的抗凋亡基因 IEX-1 L，它是 IEX-1（立即早期反应基因 X-1）的未剪接变体。我们最近使用 IEX-1 转基因 (Tg.) 小鼠的数据表明，与 IEX-1 L 类似，IEX-1 也可以在体外和体内保护 T 细胞免受 AICD 的侵害。 IEX-1 在淋巴细胞中的组成型表达导致记忆/效应样 T 细胞在脾和淋巴结中积聚，并增加对狼疮样自身免疫性疾病的易感性，这清楚地表明 IEX-1 在应答者生存中的作用T细胞。与其抗死亡活性一致，最近发现 IEX-1 可能与 Bcl-xL 和金属硫蛋白 (MT) 结合，金属硫蛋白 (MT) 是一种富含半胱氨酸的分子，可清除羟基自由基。我们假设，在 T 细胞激活的早期阶段，IEX-1 的高水平表达可以保护 T 细胞免于凋亡，而 IEX-1 的表达降低，使它们在免疫反应结束时容易受到 AICD 的影响。为了测试这一点，我们将使用含有反义 IEX-1 的逆转录病毒来抑制 IEX-1 表达，使活化的 T 细胞对凋亡敏感。我们还将检查炎症环境中抗原 (Ag) 刺激的 T 细胞中的 IEX-1 表达，以确定我们的观察结果与 IEX-1-Tg 的生理相关性。老鼠。目标 2 将通过将 T 细胞受体/IEX-l-Tg 小鼠与 IkBa (N) 杂交，确定 IEX-1 对表达或不表达截短的 IkBa (N) 的 Ag 刺激的 T 细胞寿命的体内和体外影响。 ）- 老鼠。最后，目标 3 将通过各种生化方法验证 IEX-1 与 Bcl-xL 和/或 MT 蛋白的相互作用，并将相互作用与 IEX-1 的抗死亡活性关联起来。这些研究将强调 IEX-1 在 T 细胞稳态调节中的作用，并有可能确定自身免疫性疾病治疗干预的新靶点。