IL-10 Receptor Signaling That Regulates Innate Immunity

说明(申请人提供)：IL-10是一种细胞因子，对免疫系统功能有不同的影响。它通过促进B细胞的增殖、存活和分化来促进体液免疫，但通过消除髓系细胞和淋巴细胞产生的促炎细胞因子来抑制先天免疫。IL-10通过与许多不同免疫细胞上表达的特定受体结合来显示其作用。我们以前的工作帮助定义了IL-10受体，并证明JAK-STAT信号通路是所有IL-10受体刺激功能所必需的。对IL-10受体配体结合链胞内区的结构-功能分析表明，所有IL-10‘S的作用都需要含有转录因子STAT3受体对接位点的胞内区，而IL-10’S的抗炎作用选择性地需要额外的IL-10R1羧基末端的存在。基于这一观察结果，我们询问是否可以确定IL-10诱导的基因，其调控需要IL-10R1ICD的两个功能重要区域。利用代表性差异分析，我们鉴定并克隆了一个新的IL-10诱导基因(记为Tiger)，它的诱导满足这些标准，并产生了一只缺乏Tiger基因位点的小鼠。在具体目标1中，我们建议对老虎/小鼠进行研究，以评估该基因的生理功能。IL-10依赖的TIGER诱导需要新的蛋白质合成，目前我们不知道TIGER的表达是否与IL-10‘S的抗炎作用有关。因此，在特定的目标2中，我们将进行基于微芯片的基因图谱实验，以确定一组IL-10调节的基因，它们的诱导既不依赖于蛋白质合成(即即刻早期基因)，又需要IL-10R1ICD的两个功能重要区域。然后，这些基因将用于特定的目标3，以确定IL-10受体用于选择性抑制炎症和/或先天免疫反应的信号转导途径。这项工作将确定IL-10‘S抗炎作用的分子基础，从而为我们提供新的策略，通过干扰这一信号通路来非特异性地增强对感染性物质的抵抗力。

DESCRIPTION (provided by applicant): IL-10 is a cytokine that has contrasting effects on immune system function. It promotes humoral immunity by enhancing proliferation, survival, and differentiation of B cells, but inhibits innate immunity by ablating production of pro-inflammatory cytokines from myeloid cells and from lymphocytes. IL-10manifests its effects by binding to a specific receptor expressed on many different immune cells. Our previous work helped define the IL-10 receptor and demonstrated that the JAK-STAT signaling path way is required for all IL-10 receptor stimulated functions. A structure-function analysis on the intracellular domain (ICD) of the IL-10 receptor ligand binding chain (IL10R1) revealed that, whereas all IL-10's actions required the presence of an ICD region containing the receptor docking site for the transcription factor Stat3, IL-10's anti-inflammatory effects selectively required the additional presence of the IL-10R1carboxyl terminus. Based on this observation we asked whether we could identify IL-10 induced genes whose regulation required both functionally important regions of the IL-10R1 ICD. Using representation difference analysis, we identified and cloned a novel IL-10-induced gene (denoted TIGER) whose induction fulfills these criteria and have generated a mouse that lacks the TIGER gene locus. In Specific Aim 1, we propose to study the TIGER-/- mouse to assess the physiologic function of this gene. IL-10 dependent induction of TIGER requires new protein synthesis and we currently do not know whether TIGER expression is required for IL-10's anti-inflammatory effects. Thus in Specific Aim 2 we will conduct microchip-based gene profiling experiments to identify a panel of IL-10-regulated genes whose induction is both independent of protein synthesis (i.e. are immediate-early genes) and requires both functionally important regions of the IL-10R1 ICD. These genes will then be used in Specific Aim 3 to define the signal transduction pathway that the IL-10 receptor uses to selectively inhibit inflammatory and/or innate immune responses. This work should identify the molecular basis for IL-10's anti-inflammatory effects and should thus provide us with novel strategies to nonspecifically enhance resistance to infectious agents by interfering with this signaling pathway.