Regulation of Type I IFNs in Tolerance and Autoimmunity

描述(申请人提供)：干扰素α(干扰素-a)在调节先天免疫反应和获得性免疫反应中起关键作用，主要通过激活树突状细胞(DC)。DC的异常激活可能会将自身AGS的表现从耐受转变为自身免疫，事实上，对干扰素-α的过度反应被认为是自身免疫性疾病(如狼疮)的致病因素。我们的长期目标是发现能够抑制DC对干扰素-a的反应的生物因素，并确定它们在自身免疫性疾病发展中的作用。我们最近的研究表明，IL-4在体外和体内都能抑制DC对干扰素-α的反应。我们建议研究IL-4抑制对干扰素-a的先天反应的分子机制及其对获得性免疫反应的影响。此外，我们发现来自狼疮易感小鼠的骨髓来源的DC具有固有的I型干扰素反应的过度激活，该反应被IL-4抑制，我们打算确定IL-4作为狼疮治疗的可能性。在目标I中，我们将确定IL-4抑制干扰素应答的分子机制。我们假设IL-4作用于影响旁分泌干扰素-a/b的第一反应和自分泌干扰素诱导的正反馈环路的分子。在我们对IL-4的初步研究和现有文献的基础上，我们假设一个新的IL-4诱导的蛋白可以抑制1)STAT1-2的磷酸化或2)干扰素刺激基因(ISG)的转录，如干扰素-a/b。我们将阐述IL-4R下游的哪个信号通路介导了IL-4抑制干扰素的应答，哪个机制阻断了STAT1-2的磷酸化，以及在IL-4抑制干扰素应答的过程中阻断了干扰素-b的转录。在AIM II中，我们将在体内测试IL-4对干扰素-α刺激的两种获得性免疫反应-交叉激发和同型抗体转换的作用。在目标III中，我们将确定针对DC的IL-4在狼疮自身免疫发展中的作用。我们将使用两种方案：a)注射携带IL-4的慢病毒转导的DC，b)移植相同慢病毒转导的骨髓前体细胞，并在治疗效果和副作用方面与全身应用IL-4进行比较。这个项目将阐明细胞因子对先天和适应性反应的调节，以及它们作为治疗系统性红斑狼疮的新治疗策略的潜力。此外，我们将测试两种新的针对DC的基因转移方案，这两种方案可能有助于在自身免疫和移植中传递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干扰素-a的反应的生物因素，并确定它们在自身免疫性疾病发展中的作用。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，我们的实验将测试专门针对抗原提呈细胞的基因转移的新方案。如果成功，这些方法将在自身免疫和移植中传递免疫调节和诱导耐受的基因方面具有非常宝贵的价值。

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.