Innate Intracellular Mechanisms

描述（由申请方提供）：已知病毒RNA种类在与细胞外受体（如toll样受体3（TLR 3））相互作用后是I型IFN的无意、强效诱导剂。最近，从我们小组和其他人所做的工作中可以明显看出，TLR独立的细胞内dsRNA识别机制和宿主防御信号转导机制交替存在，以诱导I型IFN来阻止病毒感染。据报道，这些过程涉及被称为RIG-1、MDA 5和LGP 2的相关解旋酶，它们作为识别病毒感染并触发I型IFN产生的细胞内受体发挥功能。据报道，RIG-I识别负链病毒，而MDA 5识别正链病毒。然而，LGP 2的功能仍有待阐明。我们的数据已经证实FADD（与死亡结构域相关的Fas）和RIP 1（受体相互作用蛋白激酶1）对于有效的RIG-I/MDA 5功能和NF-κ B和IRF-3（诱导IFN所必需的转录因子）的激活是必需的。在哺乳动物宿主防御中对FADD/RIP 1的需求是果蝇中先天免疫途径的唤起，称为IMD途径，其利用dFADD依赖性信号级联，通过激活抗微生物基因的转录来响应感染。因此，这些数据表明，存在一个保守的病原体识别途径，在哺乳动物细胞中，是中央的I型IFN和其他基因的诱导宿主防御的重要。鉴于这些数据，我们打算提出这一建议，以进一步阐明先天免疫信号传导的机制。这将包括以下目标：我们已经开发了一个可行的小鼠模型，缺乏LGP 2，并将检查这种解旋酶在先天性免疫应答病毒感染的重要性。这项研究将包括评估dsRNA转导分子MDA 5和RIG-I在先天信号传导事件中的作用，包括LGP 2的潜在调节。 我们的目标是进一步表征FADD和RIP 1在先天信号传导过程中的作用，包括在RIG-I和NDA 5介导的信号传导中的作用。本研究将涉及翻译后修饰事件在FADD功能中的作用。 我们已经分离出一种新的分子，STING，它是一种有效的IFN信号诱导剂，需要FADD才能有效地发挥作用。将确定STING在先天信号传导中的重要性。了解这些途径的功能对理解发病机制和开发新的治疗方法和疫苗以对抗疾病具有重要影响。

DESCRIPTION (provided by applicant): Viral RNA species are known to be inadvertent, potent inducers of type I IFN, following interaction with extracellular receptors such as toll-like receptor 3 (TLR 3). Recently, it has become apparent from work done by our group and others that TLR-independent, intracellular mechanisms of dsRNA recognition and host defense signal transduction alternatively exist to induce type I IFN required to thwart virus infection. These processes have been reported to involve related helicases referred to as RIG-I, MDA5 and LGP2, which putatively function as intracellular receptors which recognize virus infection and trigger the production of type I IFN. RIG-I reportedly recognizes negative stranded viruses, while MDA5 recognizes positive stranded viruses. LGP2 function, however, remains to be clarified. Our data has confirmed that FADD (Fas associated with death domain) and RIP1 (Receptor interacting protein kinase 1), are necessary for efficient RIG-I/MDA5 function and the activation of NF-kappaB and IRF-3 (transcription factors necessary for the induction of IFN). The requirement for FADD/RIP1 in mammalian host defense is evocative of innate immune pathways in Drosophila, referred to as the IMD pathway, which utilizes a dFADD-dependent signaling cascade that responds to infection by activating the transcription of anti-microbial genes. These data therefore suggest the existence of a conserved pathogen recognition pathway that, in mammalian cells, is central for the induction of type I IFN and other genes important for host defense. Given this data, we intend for this proposal, to further delineate the mechanisms of innate immune signaling. This will include the following objectives: We have developed a viable murine model that lacks LGP2 and will examine the importance of this helicase in innate immune responses to virus infection. This study will include evaluating the role of the dsRNA transducing molecules MDA5 and RIG-I in innate signaling events, including potential regulation by LGP2. We aim to further characterize the role of FADD and RIP1 in innate signaling processes, including role in RIG-I and NDA5 mediated signaling. This study will involve the role of post-translational modification events in FADD function. We have isolated a new molecule, STING, that is a potent inducer of IFN Signaling and that requires FADD for efficient activity. The importance of STING in innate signaling will be determined. Understanding how these pathways function has significant impact on understanding pathogenesis and for developing novel therapeutics and vaccines to combat disease.