Role of caspase 7 in T cell function

描述（由申请人提供）：本项目的长期目标是了解免疫应答的CD 4 T细胞臂的发展和终止的机制。这些是具有潜在广泛健康相关影响的基本过程，从理解正常免疫反应到掌握未能消除活化T细胞的可能后果，如自身免疫性疾病。 初始T细胞对抗原的应答经历克隆扩增和分化，然后主要通过分泌细胞因子发挥其作用。随后，有必要通过细胞凋亡删除这一大群活化细胞来恢复体内平衡。胱天蛋白酶7是已知对细胞死亡重要的蛋白酶家族的成员，在凋亡细胞中被激活，尽管对其功能知之甚少。令人惊讶的初步数据显示，不仅半胱天冬酶7敲除的T细胞对凋亡具有部分抗性，而且它们也不能分泌干扰素γ（一种重要的效应细胞因子），并且产生减少量的IL-2（一种对T细胞增殖和凋亡都很重要的细胞因子）。 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。在体外研究的增殖和细胞因子的产生在caspase 7缺陷的T细胞，并在体内免疫挑战，将进一步测试的假设，caspase 7是重要的T细胞功能。半胱天冬酶7和细胞因子分泌之间的机制联系将寻求通过确定其对影响细胞因子产生的信号通路的影响，并通过两种方法确定其底物：野生型和敲除T细胞之间的蛋白质裂解差异的质谱分析;和酵母双杂交筛选。半胱天冬酶7在T细胞凋亡中的作用将通过确定其与半胱天冬酶3（一种高度相关的蛋白酶，对于凋亡是重要的，但不是必需的）的组合缺陷的影响来接近。 申请人正在完成耶鲁大学儿科重症监护奖学金，并将继续在那里作为一个初级教员。拟议的研究将在免疫生物学系进行，由于高质量的教师，强大的导师，广泛的研究课题和优秀的设施，这是研究培训的理想地点。这个K 08奖将大大有助于他对细胞凋亡和T细胞免疫学的研究，并为他提供时间和资源，以发展成为一个独立的基础科学研究者。

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.