REGULATION OF THYMOCYTE APOPTOSIS BY THROMBOXANE A2

血栓烷A2对胸腺细胞凋亡的调节

• 批准号: 2886027
• 负责人: ROSLYN B MANNON
• 金额: $ 8.68万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-04-01 至 2001-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2886027
• 关键词: T lymphocyte; apoptosis; autoimmunity; biological signal transduction; cell differentiation; genetically modified animals; immune tolerance /unresponsiveness; laboratory mouse; organ culture; receptor; receptor expression; thromboxanes; thymus

DESCRIPTION: Training Plan: The clonal deletion of autoreactive thymocytes (negative selection) results from the induction of programmed cell death or apoptosis. This process is important for achieving tolerance within an individual. While loss of self-tolerance may result in autoimmune disease, the induction of tolerance to alloantigens may result in permanent organ graft acceptance. Recent studies suggest that thromboxane A2 (TxA2) produced in the thymic microenvironment may regulate thymic maturation. Thromboxane synthase, the final catalytic enzyme involved in TxA2 synthesis, is expressed within the thymus. Moreover, the thymus expresses high levels of the thromboxane receptor (TxR), far above that of other tissues tested. Finally, TxR expression has been localized to immature thymocytes and exposure of these cells to TxA2 induces apoptosis. Therefore, the hypothesis is that TxA2 binds to its receptor and, through specific signaling pathways, regulates cellular processes important to T cell maturation and selection. The goals of this project are to identify the biochemical characteristics and ontogeny of the TxR in thymocytes and identify the function of TxA2 in thymocyte development. To investigate this hypothesis, three specific aims are proposed: (1) To characterize the signal transduction pathways coupled to the TxR in thymocytes. In these studies, the signal transduction pathways coupled to the TxR in freshly isolated thymocytes will be identified by microphysiometry and active second messenger coupling confirmed by standard biochemical assays. (2) To identify which signals activated by TxR cause apoptosis in thymocytes. These studies will directly determine which of the second messengers (identified in specific aim I) mediate apoptosis of thymocytes in vitro. (3) To define the effects of TxA2 on thymocyte maturation in vitro. Using fetal thymic organ culture as a model of thymic development, the applicant will directly test the role of TxA2 in influencing the development of T cells. T cell receptor transgenic mice will be used to specifically examine the role of TxA2 in controlling negative selection of autoreactive T cell precursors. This project is expected to provide novel information regarding the expression and function of the TxR in thymocytes and the effective role of TxA2 in regulating T cell maturation. It is hoped that understanding of the role of lipid mediators in the thymic development may suggest new strategies in preventing autoimmune disease and in the induction of transplantation tolerance to organ allografts.

描述： 培训计划：自动反应性胸腺细胞的克隆缺失（阴性 选择）结果是诱导程序性细胞死亡或 凋亡。这个过程对于实现宽容很重要 个人。 虽然失去自我耐受可能会导致自身免疫性 疾病，诱导对同种抗原的耐受性可能导致 永久器官移植接受。最近的研究表明血栓烷 胸腺微环境中产生的A2（TXA2）可能调节胸腺 成熟。 血栓烷合酶，涉及的最终催化酶 在TXA2合成中，在胸腺内表达。 而且，胸腺 表达高水平的血栓烷受体（TXR），远高于 其他测试的组织。 最后，TXR表达已定位到 这些细胞未成熟的胸腺细胞和暴露于TXA2诱导 凋亡。 因此，假设是TXA2与其受体结合，并通过 特定的信号通路，调节对细胞过程至关重要 T细胞成熟和选择。 该项目的目标是 识别TXR中TXR的生化特征和个体发育 胸腺细胞并确定TXA2在胸腺细胞发育中的功能。 为了研究这一假设，提出了三个具体目标：（1） 为了表征与TXR耦合的信号转导途径 胸腺细胞。 在这些研究中，信号转导途径耦合 新鲜分离的胸腺细胞中的TXR将通过 显微生理测量和主动第二信使耦合证实 标准生化测定。 （2）确定哪些信号被激活 TXR引起胸腺细胞的凋亡。 这些研究将直接确定 第二个使者中的哪一个（特定目的i）进行了调解 胸腺细胞体外的凋亡。 （3）定义TXA2对 体外胸腺细胞成熟。 使用胎儿胸腺器官培养 胸腺发育模型，申请人将直接测试角色 TXA2影响T细胞的发展。 T细胞受体 转基因小鼠将用于专门检查TXA2在 控制自动反应性T细胞前体的负选择。 预计该项目将提供有关 TXR在胸腺细胞中的表达和功能和有效作用 TXA2在调节T细胞成熟的过程中。 希望理解 脂质介质在胸腺发育中的作用可能表明新的 预防自身免疫性疾病的策略和诱导 对器官同种异体移植的移植耐受性。