Type 1 IFN Function and Signaling in Immunity to Viruses

描述(申请人提供)：1型干扰素(IFN)，包括IFNα和β，具有强大的抗病毒作用，但也调节广泛的免疫调节功能。这包括对淋巴细胞亚群的影响。有些是矛盾的，控制1型干扰素效应的机制，允许在需要时获得子集功能，特征不佳。细胞因子确实会刺激信号通路，这取决于信号转导和转录激活因子(STAT)1和2，但它们可以有条件地激活所有的STATS，包括STAT4。由于实验证明总的STAT1蛋白在感染后的早期被显著诱导，并且STAT4的1型干扰素的激活与STAT1水平呈负相关，该项目建议检验以下假设，即1型干扰素的作用受不同细胞内信号通路的调节，并且这种调节是病毒感染的先天性和获得性免疫反应所必需的和传递的。这项工作已经证明了这些假设是正确的，并正在定义与不同途径相关的子集反应。在这一更新的申请中，我们建议进行实验，以检验这样的假设：STATS通过增强和抑制1型干扰素效应而作为分子开关促进细胞反应，以及STAT1和STAT4对相互信号通路的影响受到其他STAT分子的影响，并对其产生影响。这将通过关注T细胞反应的四个具体目标来实现。目的1将拓宽对STAT表达的理解，以及1型干扰素在感染期间获得不同T细胞亚群中单个STAT的变化的后果。目标2将机械地定义调节STAT水平的途径。目的3将通过评估实验性地调节STAT水平的后果以及在体外对细胞反应产生积极和消极影响的机制来检验STATs充当主开关的假设。目标4将确定调节STAT开关对调节感染期间的生物反应的重要性。将使用免疫学、病毒学、生化和分子技术，并将通过研究暴露于细胞因子后的体外反应以及野生型和转基因小鼠的淋巴细胞性脉络膜脑膜炎病毒感染后的体内反应来推进这项工作。该项目承诺继续推进对1型干扰素在形成感染免疫反应中的控制作用的理解，并为在治疗应用中使用细胞因子提供见解。然而，更广泛地说，它将确定如何调节细胞因子效应以为有限数量的基因增加价值的范例。 公共卫生相关性：1型干扰素(IFN)调节广泛的生物效应，其中一些是自相矛盾的。这项工作旨在了解它们的功能如何被调节，以获得和控制感染期间促进健康所需的子集反应。由于1型干扰素也被用于癌症、慢性丙型肝炎病毒感染和多发性硬化症的治疗，而且消融方案正在开发以阻止它们对自身免疫性疾病的贡献，因此这些结果对于设计预防疾病的治疗方案具有广泛的相关性。

DESCRIPTION (provided by applicant): The type 1 interferons (IFNs), including the IFNs alpha and beta, have potent antiviral effects, but also mediate a wide range of immunoregulatory functions. These include effects on lymphocyte subsets. Some are paradoxical, and the mechanisms controlling type 1 IFN effects, to allow access to subset functions when needed, are poorly characterized. The cytokines do stimulate a signaling pathway, depending on the signal transducers and activators of transcription (STAT) 1 and 2, but they can conditionally activate all of the STATs, including STAT4. As a result of experiments demonstrating that total STAT1 protein is dramatically induced at early times after infection, and that type 1 IFN activation of STAT4 negatively correlates with STAT1 levels, this project proposed to test the hypotheses that type 1 IFN effects are controlled by regulation of access to different intracellular signaling pathways, and that this regulation is required and delivered during innate and adaptive immune responses to viral infections. The work has proven the hypotheses to be correct, and subset responses linked to different pathways are being defined. Experiments are proposed in this renewal application to test the hypotheses that STATs act as molecular switches in promoting cellular responses by both enhancing and inhibiting type 1 IFN effects, and that the STAT1 and STAT4 effects on the reciprocal signaling pathway are influenced by, and have consequences for, other STAT molecules. This will be accomplished through four specific aims focusing on T cell responses. Aim 1 will broaden the understanding of STAT expression and the consequences of changes for type 1 IFN access to individual STATs in different T cell subsets during infection. Aim 2 will mechanistically define the pathways regulating STAT levels. Aim 3 will test the hypothesis that STATs act as master switches by evaluating the consequences of experimentally modulating STAT levels and the mechanisms for resulting positive and negative effects on cellular responses ex vivo. Aim 4 will define the importance of modulating STAT switches for regulating biological responses during infections. Immunological, virological, biochemical, and molecular techniques will be used, and the work will be advanced by studies of responses ex vivo following exposure to cytokines, and in vivo following lymphocytic choriomeningitis virus infections in wild type and genetically altered mice. The project promises to continue to advance understanding of the control of type 1 IFN effects in shaping immune responses to infection, and to provide insights for use of cytokines in therapeutic applications. Even more broadly, however, it will identify paradigms for how cytokine effects are regulated to add value to a limited number of genes. PUBLIC HEALTH RELEVANCE: The type 1 interferons (IFNs) mediate a wide range of biological effects, and some of these are paradoxical. This work is directed at understanding how their functions are regulated to access and control subset responses as needed in promoting health during infections. Because type 1 IFNs are also being used, with uneven success, in the treatments of cancer, chronic hepatitis C virus infections, and multiple sclerosis, and ablation protocols are being developed to block their contribution to autoimmune diseases, the results have broad relevance for the design of therapeutic protocols in protection against disease.