Regulation of Type I IFNs in Tolerance and Autoimmunity

描述（由申请人提供）：干扰素α (IFN-a)在先天和适应性免疫反应的调节中起关键作用，主要通过激活树突状细胞（dc）。dc的异常激活可能将自身ags的表现从耐受性转变为自身免疫，事实上，对IFN-a的过度反应已被认为是狼疮等自身免疫性疾病的致病性。我们的长期目标是发现能够抑制dc对IFN-a反应的生物因素，并确定它们对自身免疫性疾病发展的影响。我们最近的研究表明，IL-4在体外和体内抑制DCs对IFN-a的反应。我们建议研究IL-4抑制IFN-a先天应答的分子机制及其对适应性免疫应答的影响。此外，我们发现来自狼疮易感小鼠的骨髓来源的dc具有被IL-4抑制的I型IFN反应的内在超激活，我们打算确定IL-4作为狼疮治疗的潜力。在Aim I中，我们将确定IL-4抑制IFN反应的分子机制。我们假设IL-4作用于影响旁分泌IFN-a/b的第一反应和自分泌IFNab诱导的正反馈回路的分子。根据我们的初步研究和现有的关于IL-4的文献，我们假设一种新的IL-4诱导蛋白可以抑制1)STAT1-2的磷酸化或2)IFN刺激基因（ISG）如IFN-a/b的转录。我们将讨论IL-4R下游的哪个信号通路介导IL-4抑制IFN反应，哪种机制阻断STAT1-2磷酸化，以及哪种机制在IL-4抑制IFN反应期间阻断IFN-b转录。在Aim II中，我们将在体内测试IL-4对IFN-a、交叉引物和同型抗体转换两种适应性免疫反应的刺激作用。在Aim III中，我们将确定靶向dc的IL-4对狼疮自身免疫发展的影响。我们将采用两种方案：a)注射由携带IL-4的慢病毒转导的dc， b)移植由相同慢病毒转导的骨髓祖细胞，并将它们与全身给药IL-4进行比较，在治疗效果和副作用的发展方面。本项目将揭示细胞因子对先天和适应性反应的调控及其作为治疗系统性红斑狼疮的新治疗策略的潜力。此外，我们将测试两种针对dc的基因转移的新方案，这可能有助于在自身免疫和移植中提供免疫调节和诱导耐受的候选基因。公共卫生相关性：我们的长期目标是发现能够抑制树突状细胞对IFN- a反应的生物因素，并确定其对自身免疫性疾病发展的影响。该项目将阐明细胞因子对先天和适应性反应的调节，并将确定治疗系统性红斑狼疮的新治疗策略的潜力。此外，我们的实验将测试新的基因转移方案，特别是针对抗原提呈细胞。如果成功，这些方法将对递送免疫调节基因和诱导自身免疫耐受以及移植具有不可估量的价值。

DESCRIPTION (provided by applicant): Interferon alpha (IFN-a) is a pivotal player in the regulation of the innate and the adaptive immune responses, primarily through the activation of dendritic cells (DCs). Abnormal activation of DCs may shift the presentation of self-Ags from tolerance to autoimmunity and, indeed, excessive responses to IFN-a have been proposed to be pathogenic in autoimmune diseases such as lupus. Our long-term goal is to discover biologic factors able to inhibit the response to IFN-a in DCs and determine their effects on the development of autoimmune diseases. Our recent studies indicate that IL-4 suppresses the response of DCs to IFN-a in vitro and in vivo. We propose to investigate the molecular mechanisms by which IL-4 inhibits the innate response to IFN-a and the consequences on the adaptive immune responses. Furthermore, we have found that bone marrow-derived DCs from lupus-prone mice have an intrinsic hyperactivation of the Type I IFN response that is inhibited by IL-4 and we intend to determine the potential of IL-4 as therapy in lupus. In Aim I, we will determine the molecular mechanisms underlying IL-4 suppressive effects on IFN responses. We hypothesize that IL-4 acts on molecules that affect both the first response to paracrine IFN-a/b and the positive feedback loop induced by autocrine IFNab. On the basis of our Preliminary Studies and available literature on IL-4, we hypothesize that a newly IL-4-induced protein inhibits either 1) the phosphorylation of STAT1-2 or 2) the transcription of IFN stimulated genes (ISG) such as IFN-a/b. We will address which signaling pathway, downstream of IL-4R, is mediating IL-4 suppression of IFN response, which mechanism is blocking the STAT1-2 phosphorylation and which mechanism is blocking IFN-b transcription during IL-4 suppression of IFN response. In Aim II, we will test the effects of IL-4 on the stimulation of two adaptive immune responses stimulated by IFN-a, cross-priming and isotype antibody switching in vivo. In Aim III, we will determine the effects of IL-4 targeted to DCs on the development of lupus autoimmunity. We will use two protocols: a) injection of DCs transduced with a lentivirus carrying IL-4, and b) transplantation of bone marrow progenitors transduced with the same lentivirus, and will compare them with systemic administration of IL-4, in terms of therapeutic efficacy and development of side effects. This project will shed light on the regulation of the innate and adaptive responses by cytokines and their potential as novel therapeutic strategy to cure systemic lupus erythematosous. In addition, we will test two novel protocols of gene transfer targeting DCs that may be useful to deliver candidate genes for immune-modulation and induction of tolerance in autoimmunity and transplantation. Public Health Relevance: Our long-term goal is to discover biologic factors able to inhibit the response to IFN- a in dendritic cells and determine their effects on the development of autoimmune diseases. This project will shed light on the regulation of the innate and adaptive responses by cytokines and will determine the potential of novel therapeutic strategies to cure systemic lupus erythematosous. In addition, our experiments will test novel protocols of gene transfer specifically targeting Antigen Presenting Cells. If successful, these approaches will be invaluable for delivery of genes for immune-modulation and induction of tolerance in autoimmunity as well as in transplantation.