Regulation of Type I IFNs in Tolerance and Autoimmunity

描述（由申请人提供）：干扰素α（IFN-α）主要通过激活树突状细胞（DC），在先天性和适应性免疫应答的调节中起关键作用。DC的异常活化可将自身Ag的呈递从耐受性转变为自身免疫性，并且事实上，已提出对IFN-α的过度应答在自身免疫性疾病如狼疮中是致病的。我们的长期目标是发现能够抑制DC中对IFN-α的反应的生物因子，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DC对IFN-α的反应。我们建议研究IL-4抑制对IFN-α的先天性应答的分子机制以及对适应性免疫应答的后果。此外，我们已经发现，骨髓来源的树突状细胞从狼疮易感小鼠有一个内在的超活化的I型IFN的反应，抑制IL-4，我们打算确定的潜力IL-4作为治疗狼疮。在目的I中，我们将确定IL-4对IFN应答的抑制作用的分子机制。我们假设IL-4作用于影响对旁分泌IFN-α/B的第一反应和由自分泌IFN α B诱导的正反馈环的分子。基于我们的初步研究和关于IL-4的现有文献，我们假设新的IL-4诱导的蛋白抑制1）STAT 1 -2的磷酸化或2）IFN刺激的基因（ISG）如IFN-α/B的转录。我们将讨论IL-4 R下游的信号通路介导IL-4抑制IFN应答，其机制是阻断STAT 1 -2磷酸化，以及在IL-4抑制IFN应答期间阻断IFN-b转录。在目的II中，我们将测试IL-4对由IFN-α刺激的两种适应性免疫应答的刺激的影响，交叉致敏和体内同种型抗体转换。在目的III中，我们将确定IL-4靶向DC对狼疮自身免疫发展的影响。我们将使用两个协议：a）注射用携带IL-4的慢病毒转导的DC，和B）移植用相同慢病毒转导的骨髓祖细胞，并将它们与全身施用IL-4在治疗功效和副作用的发展方面进行比较。本项目将阐明细胞因子对先天性和适应性反应的调节及其作为治疗系统性红斑狼疮的新策略的潜力。此外，我们将测试两种新的基因转移靶向DC的协议，可能是有用的，以提供候选基因的免疫调节和诱导耐受性的自身免疫和移植。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-α反应的生物因子，并确定它们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性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，我们的实验将测试特异性靶向抗原呈递细胞的基因转移的新方案。如果成功的话，这些方法将是非常宝贵的基因传递免疫调节和诱导耐受性的自身免疫以及移植。

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.