TOLL-LIKE RECEPTORS: ACTIVATORS OF INNATE IMMUNITY

描述：（改编自申请人摘要）Toll样受体（TLR） 介导的先天免疫识别病原体的物种，如苍蝇 还有人类本提案的目的是分析细胞内 TLR的信号传导结构域相互作用， 对细菌产物作出反应的促炎信号。我们证明 先前的研究表明，虽然TLR 4的胞质尾区的二聚化是 足以诱导TNF-α的产生，细胞质的二聚化， TLR 2或TLR 6的尾部则没有。相比之下， TLR 2和TLR 6的胞质尾诱导TNF-α。因此， 二聚体诱导的信号传导在这两个受体对之间是不同的。我们 建议绘制TLR 4胞质结构域的元件， 同源二聚体诱导的信号传导，并绘制细胞质结构域的元件 TLR 2/6介导异源二聚体诱导的信号传导。生物 这两种类型的信号传导的结果是不同的;而TLR 4 同源二聚体诱导趋化因子IP-10，而TLR 2/6异源二聚体不诱导。我们将 定义特异性介导TLR 4的胞质结构域的区域， 诱导IP- 10，并鉴定与TLR 4结合的信号分子 同源二聚体，而不是TLR 2/6异源二聚体。尽管我们已经证明 以前认为TLR 4介导巨噬细胞中的LPS应答，而TLR 2/6介导巨噬细胞中的LPS应答， 介导对肽聚糖的反应，有诱人的证据表明， 在某些情况下，TLR 2可能参与LPS诱导的反应。一个这样 环境是IL-12的诱导; TLR 2的一个显性负突变体 特异性地消除这种反应，而不同的TLR 2突变体不能。 有趣的是，两种突变体都不能阻断LPS诱导的TNF-α。这一区别应 使我们能够绘制TLR 2胞质结构域的不同区域， 参与LPS诱导的IL-12产生。我们使用了一种快速而强大的 定位TLR胞质结构域的信号传导能力的方法 2，4和6二聚体，我们将扩大这些研究，以检查的能力， 所有10个TLRS的胞质结构域产生促炎信号。 因此，该建议将定义不同对的信号库 以及这些分子的胞质区域 负责触发不同的反应，如导致TNF-cz的反应， IP-10和IL-12。

DESCRIPTION: (Adapted from applicant's abstract) The Toll-like receptors (TLRs) mediate innate immune recognition of pathogens in species as diverse as flies and humans. The purpose of this proposal is to analyze how the intracellular signaling domains of TLRs interact with each other to generate distinct pro-inflammatory signals in response to bacterial products. We demonstrated previously that while dimerization of the cytoplasmic tail of TLR4 is sufficient to induce the production of TNF-a, dimerization of the cytoplasmic tails of either TLR2 or TLR6 does not. In contrast, heterodimerization of the cytoplasmic tails of TLR2 and TLR6 does induce TNF-a. Thus, the mechanism of dimer-induced signaling is different between these two receptor pairs. We propose to map the elements of the cytoplasmic domain of TLR4 that mediate homodimer-induced signaling, and to map the elements of the cytoplasmic domains of TLR2/6 that mediate heterodimer-induced signaling. The biological consequences of these two types of signaling are different; while TLR4 homodimers induce the chemokine IP-lO, TLR2/6 heterodimers do not. We will define the regions of the cytoplasmic domain of TLR4 that specifically mediate the induction of IP- 10, and identify signaling molecules that bind to TLR4 homodimers, and not to TLR2/6 heterodimers. Although we have demonstrated previously that TLR4 mediates LPS-responses in macrophages, while TLR2/6 mediates responses to peptidoglycan, there is tantalizing evidence that under certain circumstances, TLR2 may participate in LPS-induced responses. One such circumstance is the induction of IL-12; one dominant negative mutant of TLR2 specifically ablates this response while a distinct TLR2 mutant does not. Interestingly, neither mutant blocks LPS-induced TNF-a. This distinction should permit us to map distinct areas of the cytoplasmic domain of TLR2 that participate in LPS-induced IL-12 production. We have used a rapid and robust method for mapping the signaling capacity of the cytoplasmic domains of TLR 2,4, and 6 dimers, and we will extend these studies to examine the capacity of the cytoplasmic domains of all ten TLRS to generate pro-inflammatory signals. This proposal will therefore define the signaling repertoire of different pairs of TLRs, as well as the regions of the cytoplasmic domains of these molecules responsible for triggering distinct responses such as those leading to TNF-cz, IP-lO, and IL-12.