Regulation of Fas-mediated Apoptosis

Fas 介导的细胞凋亡的调节

• 批准号: 6333643
• 负责人: THOMAS L ROTHSTEIN
• 金额: $ 28.02万
• 依托单位: BOSTON MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-07-01 至 2003-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6333643
• 关键词: B lymphocyte; CD95 molecule; anergy; apoptosis; autoimmunity; gene expression; gene targeting; genetic regulation; genetically modified animals; laboratory mouse; pathologic process; western blottings

DESCRIPTION (provided by applicant): Fas (CD95) is of principal importance to normal functioning of the immune system, as evidenced by the marked dysregulation of autoreactive B cells and accompanying autoantibody formation that characterize Fas-deficient animals. The sensitivity of B cells to Fas-mediated apoptosis is regulated by specific receptor signaling, in which surface immunoglobulin engagement, and IL-4R engagement, produces a state of Fas resistance. Modulation of susceptibility to Fas killing suggests a system that protects B cells during critical interactions with FasL-bearing, activated T cells, but that can contribute to the survival of autoreactive B cells when activated inappropriately. The broad, long term objective of this work is to understand the role of inducible Fas-resistance in normal immune responses and in the genesis of autoimmunity. Three antiapoptotic gene products are implicated as proximate mediators for resistance to Fas killing: FAIM, FLIP, and Bcl-xL. The specific goal of this work is to illuminate the capability of these molecules to enhance serological immune responses and to alter the behavior of autoreactive B cells, separate from any other collateral effects of sIg or IL-4R engagement. This will be accomplished through 4 specific aims. 1. Determine the FAIM-dependency of normal immune responses by constructing and evaluating FAIM-deficient (knock-out) mice. 2. Evaluate the level, timing, and cellular origin of upregulated FAIM, FLIP, and Bcl-XL expression in lymphoid tissue during in vivo immune responses. 3. Compare the relative potency of FAIM, FLIP, and Bcl-xL in producing Fas-resistance in primary B cells by retroviral transduction in vitro and in promoting normal immune responses in vivo by constructing mixed chimeras in which bone marrow donors overexpress anti-apoptotic molecules alone and together. 4. Test the influence of FAIM, FLIP, and Bcl-xL, on the behavior of autoreactive B cells in two well-defined models: a) Ig receptor transgenic mice expressing VH3H9 anti-dsDNA in which B cells normally fail to enter germinal centers but do so on a Fas-deficient background; and, b) doubly transgenic mice expressing anti-HEL BCR and soluble HEL in which B cells are normally short-lived and tolerant but break tolerance in the presence of IL-4, B7.2, or Fas-deficiency. The results of these studies will test the hypothesis that inducible Fas-resistance promotes normal immune responses, and the hypothesis that aberrant Fas-resistance contributes to a breakdown in autoreactive B cell tolerance, and will thereby enhance understanding of both immunization strategy and the origin of autoimmunity.

描述(由申请人提供)：Fas(CD95)对 免疫系统的正常运作，如被标记的 自身反应性B细胞调节失调及伴随的自身抗体形成 这是Fas缺陷动物的特征。B细胞对免疫球蛋白的敏感性 Fas介导的细胞凋亡受特异性受体信号的调节，其中 表面免疫球蛋白结合和IL-4R结合产生一种状态 Fas耐药。对Fas杀伤易感性的调节提示了一种系统 在与FasL的关键相互作用过程中保护B细胞，激活 T细胞，但这可以促进自身反应性B细胞的存活 不适当地激活。这项工作的广泛、长期目标是 了解可诱导的Fas抵抗在正常免疫反应中的作用 在自身免疫的起源中。三种抗凋亡基因产品是 被牵连为抵抗Fas杀伤的直接调解人：Fim，Flip， 和Bclxl。这项工作的具体目标是阐明 这些分子可以增强血清学免疫反应并改变 自身反应性B细胞的行为，与任何其他副作用分开 SIG或IL-4R参与。这将通过4个具体目标来实现。1. 通过构建和确定正常免疫反应的失败依赖性 评估FAIM缺陷(敲除)小鼠。2.评估级别、时间和 淋巴组织中FIIM、FliP和Bclxl表达上调的细胞来源 组织在体内的免疫反应中。3.比较两种药物的相对效力 FIIM、FliP和Bclxl在原代B细胞产生Fas耐药中的作用 逆转录病毒体外转导及促进小鼠正常免疫反应的研究 通过构建骨髓供者过度表达的混合嵌合体来实现活体 单独和共同作用的抗凋亡分子。4.测试FAIM的影响， Flip和Bclxl对自身反应性B细胞在两个明确定义的 模型：A)表达VH3H9抗双链DNA的免疫球蛋白受体转基因小鼠 细胞通常不能进入生发中心，但在Fas缺陷的情况下会这样做 背景；以及，b)表达抗HEL bcr和sIL的双转基因小鼠 其中B细胞通常是短暂和耐受的，但打破了耐受 在IL-4、B7.2或Fas缺乏的情况下。这些研究的结果 将检验可诱导的Fas抵抗促进正常免疫的假设 反应，并假设异常的Fas抵抗有助于 自身反应性B细胞耐受性的崩溃，从而将增强 了解免疫策略和自身免疫的起源。