Role of caspase 7 in T cell function

描述(由申请人提供)：这个项目的长期目标是了解免疫反应的CD4T细胞臂的发展和终止的潜在机制。这些都是基本的过程，具有潜在的广泛的健康相关影响，从理解正常的免疫反应到掌握未能消除激活的T细胞的可能后果，例如自身免疫性疾病。 幼稚T细胞在抗原刺激下进行克隆性扩增和分化，然后主要通过分泌细胞因子发挥作用。随后，有必要通过通过细胞凋亡删除大量的激活细胞来恢复动态平衡。Caspase 7是已知对细胞死亡起重要作用的蛋白水解酶家族中的一员，在凋亡细胞中被激活，尽管人们对其功能知之甚少。令人惊讶的初步数据显示，caspase 7基因敲除的T细胞不仅部分抵抗凋亡，而且它们也无法分泌重要的效应细胞因子干扰素-伽马，并产生数量减少的IL-2，而IL-2对T细胞增殖和凋亡都很重要。 候选人建议进一步研究caspase 7在T细胞细胞因子分泌和凋亡中的作用。对caspase7缺陷T细胞的增殖和细胞因子产生的体外研究，以及体内免疫挑战，将进一步检验caspase7对T细胞功能重要的假说。将通过确定其对影响细胞因子产生的信号通路的影响以及通过两种方法鉴定其底物来寻求caspase 7与细胞因子分泌之间的机制联系：野生型和基因敲除T细胞之间蛋白质切割差异的质谱分析；酵母双杂交筛选。Caspase7在T细胞凋亡中的作用将通过确定其缺陷与caspase3的联合作用来探讨，caspase3是一种高度相关的蛋白酶，对于细胞凋亡是重要的，但不是必需的。 申请者将在耶鲁大学完成儿科重症监护的奖学金，并将作为初级教员继续在那里工作。拟议的研究将在免疫生物学系进行，由于高质量的师资、强大的指导、广泛的研究课题和出色的设施，这是进行研究培训的理想地点。这一K08奖项将极大地帮助他在细胞凋亡和T细胞免疫学方面的研究，并为他提供时间和资源，以发展成为一名独立的基础科学研究人员。

DESCRIPTION (provided by applicant): The long-term objective of this project is to understand the mechanisms underlying the development and termination of the CD4 T cell arm of the immune response. These are fundamental processes with potentially wide health-related implications, from comprehending the normal immune response to grasping the possible consequences of a failure to eliminate activated T cells, such as autoimmune disease. Naive T cells undergo clonal expansion and differentiation in response to antigen, then exert their effects primarily through the secretion of cytokines. Subsequently, it is necessary to restore homeostasis by deleting this large population of activated cells by apoptosis. Caspase 7, a member of a family of proteases known to be important for cell death, is activated in apoptotic cells, though little is known of its function. Surprising preliminary data shows that not only are caspase 7 knockout T cells partially resistant to apoptosis, but they also fail to secrete interferon gamma, an important effector cytokine, and produce reduced amounts of IL-2, a cytokine important for both T cell proliferation and apoptosis. The candidate proposes to further study the role of caspase 7 in T cell cytokine secretion and apoptosis. In vitro studies of proliferation and cytokine production in caspase 7 deficient T cells, and in vivo immunologic challenge, will further test the hypothesis that caspase 7 is important for T cell function. A mechanistic link between caspase 7 and cytokine secretion will be sought by determining its effects on signaling pathways that influence cytokine production and by identifying its substrates with two approaches: mass spectrometry of differences in protein cleavage between wild type and knockout T cells; and yeast two-hybrid screening. The role of caspase 7 in T cell apoptosis will be approached by determining the effects of its combined deficiency with caspase 3, a highly related protease that is important, but not necessary, for apoptosis. The applicant is completing a fellowship at Yale University in Pediatric Critical Care, and will continue there as a junior faculty member. The proposed research will be done in the Department of Immunobiology, an ideal location for research training due to quality faculty, strong mentorship, breadth of research topics and outstanding facilities. This K08 award will greatly assist his research into apoptosis and T cell immunology, and provide him with time and resources to develop into an independent basic science investigator.