TRAIL receptor in apoptosis and the immune system

描述：(申请人提供)：TRAIL(肿瘤坏死因子相关 凋亡诱导配体)是肿瘤坏死因子的一员 超级大家庭。它可以杀死多种肿瘤细胞，但没有明显的效果 在大多数正常细胞上。已在人类体内发现了几种TRAIL受体。 其中包括DR4、DR5、DcR1和DcR2。DR4和DR5包含一个死亡区域 它们的细胞质拖尾，当过度表达时会引发细胞死亡。在……里面 相比之下，DcR1和DcR2不编码任何死亡区域，也不能启动 细胞凋亡。这些所谓的诱饵受体DcR1和DcR2可以作为一种 DR4和DR5的显性负性突变体，至少在瞬时转染中是这样 实验。TRAIL及其受体的生理功能较差 明白了。最近，可溶的人类DRS蛋白被证明会加剧 胶原诱导的自身免疫和外源性TRAIL抑制T细胞 扩散。因此，TRAIL可能作为一种负性调节分子 免疫系统。了解TRAIL及其受体的生理功能 受体(S)，小鼠cdna克隆，编码与 分离了人DR4和DR5(rnDR4/5)。相同的另一种拼接 发现该基因产生的蛋白相同，但没有死亡结构域(MDCR)。 瞬时转染mDR4I5但不能诱导MDCR诱导细胞凋亡，且稳定 MDR4/5在FADD细胞中的表达增加了TRAIL的敏感性。为了澄清 TRAIL受体及其胞浆截短型(MDCR)在细胞周期调控中的作用 免疫系统，缺乏蛋白质的小鼠和缺乏DCR的小鼠将是 已生成。组织特异性空mDR4/5也将使用cre-loxP 技术DR4/5和DCR突变对T淋巴细胞发育的影响 并将检查B细胞耐受性和免疫反应。类似于FasL， TRAIL介导的细胞凋亡是通过FADD介导的。这就引出了一个问题： 相同的细胞如何对TRAIL耐药但对FasL介导的Fas敏感 细胞凋亡。受体胞质-尾部互换实验解剖 提出了造成这一现象的根本原因。编码mDR4/5-Fas的逆转录病毒 (DR4/5胞外结构域与Fas死亡结构域融合)或相互作用 Fas-mDR4/5嵌合蛋白将用于感染野生型或LPR/LPR T 细胞。TRAIL或FasL对表达TRAIL或FasL的T细胞的凋亡作用 将对嵌合蛋白进行评估。成功完成这些实验 应该导致对癌症与正常的不同之处有一个重要的理解 细胞和TRAIL受体如何在免疫系统中发挥作用。

DESCRIPTION: (provided by applicant): TRAIL (tumor necrosis factor-related apoptosis inducing ligand) is a member of the tumor necrosis factor superfamily. It can kill a variety of tumor cells but has no appreciable effect on most normal cells. Several TRAIL receptors have been identified in human. These include DR4, DR5, DcR1 and DcR2. DR4 and DR5 contain a death domain in their cytoplasmic tails and can initiate cell death when over-expressed. In contrast, DcRl and DcR2 do not encode any death domain and cannot initiate apoptosis. These so-called decoy receptors, DcR1 and DcR2, can instead act as a dominant negative mutant for DR4 and DR5, at least in transient transfection experiments. The physiological function of TRAIL and its receptors are poorly understood. Recently, soluble human DRS protein was shown to exacerbate collagen-induced autoimmunity and exogenous TRAIL was shown to inhibit T cell proliferation. Thus, TRAIL might act as a negative regulatory molecule for the immune system. To understand the physiological function of TRAIL and its receptor(s), a mouse cDNA clone that encodes a protein with equal homology to human DR4 and DR5 was isolated (rnDR4/5). An alternative splicing of the same gene was found to yield an identical protein without a death domain (mDcR). Transient transfection of mDR4I5 but not mDcR leads to apoptosis, and stable expression of mDR4/5 in FADD+ cells confers TRAIL sensitivity. To elucidate the role of this TRAIL receptor and its cytoplasmic-truncated form (mDcR) in the immune system, mice lacking both proteins and mice lacking DcR will be generated. Tissue-specific null mDR4/5 will also be made using the cre-loxP technology. The effect of DR4/5 and DcR mutation on lymphocyte development, T and B cell tolerance and immune responses will be examined. Similar to FasL, TRAIL-mediated apoptosis is mediated through FADD. This raises the question to how the same cells can be resistant to TRAIL but are sensitive to FasLmediated apoptosis. A receptor cytoplasmic-tail swapping experiment to dissect the underlying reasons for this is proposed. Retroviruses encoding mDR4/5-Fas (DR4/5 extracellular domain fused to the Fas death domain) or the reciprocal Fas-mDR4/5 chimeric proteins will be used to infect wild type or lpr/lpr T cells. The apoptotic effect of TRAIL or FasL on T cells expressing these chimeric proteins will be assessed. Successful completion of these experiments should lead to a significant understanding of how cancer differs from normal cells and how TRAIL receptor functions in the immune system.