Functions of Transmembrane and Soluble Fas ligand

跨膜和可溶性 Fas 配体的功能

• 批准号: 6320400
• 负责人: Ann Marshak-Rothstein
• 金额: $ 27.06万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-03-14 至 2006-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6320400
• 关键词: SCID mouse; antigen presenting cell; apoptosis; cytotoxic T lymphocyte; enzyme activity; eye; gene deletion mutation; genetically modified animals; helper T lymphocyte; inflammation; leukocyte activation /transformation; lung; lymphoma; membrane proteins; metalloendopeptidases; neoplasm /cancer immunology; neutrophil; ovalbumin

DESCRIPTION: (Provided by applicant) Fas ligand (FasL) is a transmembrane protein originally described as a proapoptotic molecule inducibly expressed on cytotoxic T cells. Recent studies have shown that FasL expression can also trigger an inflammatory response, depending on the nature and status of the Fas+ target population. As such, it is evident that FasL expression must be stringently regulated. One aspect of this regulation is the ability of the membrane-bound form of FasL to be cleaved by a metalloproteinase; such cleavage rapidly reduces the level of FasL cell expression and releases a soluble protein that serves as an antagonist. Thus the overall impact of FasL expression is a balance between the membrane-bound and soluble forms.FasL can also be constitutively expressed by non-lymphoid tissues and, in some of these cases, FasL expression has been linked to the immune privilege of certain tissues or immune evasion of certain tumors. The significance of cleavage at these sites are unknown. The functional properties of transfected cell lines that express either wildtype FasL (wtFasL), membrane-only FasL (mFasL), or soluble-only FasL (sFasL) have been compared, and cells expressing mFasL were found to be remarkably more potent effectors than their wtFasL counterparts. For example, mFasL cells kill Fas+ target cells 5-10 times more effectively than wtFasL cells; mFasL cells induce greater neutrophil extravasation into the peritoneum than wtFasL cells; and mFasL lymphoma cells injected into syngeneic mice via the "immunoprivileged" anterior chamber of the eye are rejected and induce long-term immunity. Based on these observations, the goals of the current application will be two-fold. First, to analyze the cell types responsible for FasL-triggered tumor rejection and long term immunity and to further explore potential applications of mFasL expression to tumor immunotherapy regimens and secondly, to determine how cleavage moderates the function of FasL expressed by lymphoid and non-lymphoid tissues.This analysis will be facilitated by the use of a knock-in mouse strain rendered incapable of FasL cleavage as a result of gene-targeted deletion of the FasL metalloproteinase site. These studies will help to assess the feasibility of clinical applications of forced FasL expression and they should further reveal the significance of FasL expression by non-lymphoid tissues.

描述：(申请人提供)Fas配体(FasL)是一种跨膜 最初被描述为诱导表达的促凋亡分子的蛋白质 细胞毒T细胞。最近的研究表明，FasL的表达也可以 触发炎症反应，具体取决于 Fas+目标人群。因此，显然FasL的表达必须是 严格监管。这一规定的一个方面是， 膜结合形式的FasL被金属蛋白酶切割；这种切割 迅速降低FasL细胞表达水平，释放可溶性 作为拮抗剂的蛋白质。因此，FasL的总体影响 表达是膜结合和可溶性之间的平衡。FasL可以 也由非淋巴组织结构性表达，在其中一些组织中 在某些病例中，FasL的表达已经与某些免疫豁免权有关 某些肿瘤的组织或免疫逃逸。卵裂的意义 这些地点是未知的。转基因细胞系的功能特性 表达野生型FasL(WtFasL)、纯膜型FasL(MFasL)或 比较了可溶性FasL(SFasL)和表达mFasL的细胞 发现它们比wtFasL的对应物具有更强的效应性。 例如，mFasL细胞对Fas+靶细胞的杀伤效率要高5-10倍 与wtFasL细胞相比，mFasL细胞可诱导更多的中性粒细胞渗入 腹膜比wtFasL细胞；和mFasL淋巴瘤细胞注射同基因 小鼠通过眼球前房免疫排斥反应， 诱导长期免疫。基于这些观察，世界银行的目标 目前的申请将是双重的。首先，分析细胞类型 负责FasL引发的肿瘤排斥反应和长期免疫，并 进一步探讨mFasL表达在肿瘤中的潜在应用 第二，确定卵裂如何缓和 淋巴组织和非淋巴组织表达FasL的功能分析 将通过使用敲入的小鼠品系来促进，使其无法 基因靶向缺失FasL导致的FasL切割 金属蛋白酶部位。这些研究将有助于评估 强迫表达FasL的临床应用及应进一步揭示 非淋巴组织中FasL表达的意义