Cellular RNAs in anti-viral immunity to HSV1

项目摘要 双链RNA（dsRNA）是一种有效的病原体相关分子模式（PAMP）， 抑制蛋白质合成和病毒复制的内在抗病毒防御。病毒RNA以前被认为 然而，作为细胞dsRNA传感器的主要配体，细胞RNA最近被揭示为 能够抑制和促进其活化的核酸PAMP反应的主要调节剂。虽然 HSV 1受dsRNA依赖的抗病毒效应物PKR和RNase L的限制，什么RNA激活这些效应物？ 酶和贡献的新特征的细胞校准这些反应是完全 未知我们的总体目标是了解细胞RNA如何有助于抗病毒免疫， HSV 1感染。dsRNA依赖性反应被几种HSV 1编码的蛋白质抵消， 强调了这项任务的重要性。这些包括vhs，一种加速mRNA衰变的核糖核酸内切酶 最大限度地减少dsRNA的积累和Us11，它结合dsRNA，阻止eIF2 α激酶PKR的激活 和RNase L.我们的初步结果表明，存在两种相反的机制，细胞RNA也 调节HSV 1感染细胞中dsRNA依赖性细胞内在防御。首先，我们假设细胞 环状（circ）RNA，通过Us11保护免于RNA酶L活化，并选择性地保护免于vhs切割， 抑制PKR活化。其次，我们假设HSV 1诱导的dsRNA不是完全由病毒编码的， 相反，含有依赖于cGAS-STING的细胞溶质DNA传感的细胞RNA组分， 诱导I型干扰素（IFN）响应HSV1的途径。这将构成一种新的信号模式， 病原性DNA和RNA胞质检测系统之间的扩增和串扰。我们将测试这些 在两个特定目标中的假设，（i）确定circRNA在HSV 1感染生物学中的作用;和（ii）定义 cGAS-STING dsDNA传感途径如何影响dsRNA丰度和/或抗病毒dsRNA依赖性 先天免疫反应这些特定目标的完成将揭示细胞内在先天免疫是如何 在感染过程中，应答受宿主RNA和平行的先天免疫信号传导途径的调节。 HSV1是一种重要的人类病原体。这项探索性研究的结果可能适用于 各种各样的致病性人类病毒，并可能揭示治疗病毒感染的新策略。在 此外，他们将提供重要的见解之间的串扰先天免疫信号通路， dsDNA和dsRNA是癌症和自身免疫性疾病的重要治疗靶标。

Project Summary Double-stranded RNA (dsRNA) is a potent pathogen-associated molecular pattern (PAMP) that activates cell intrinsic antiviral defenses that inhibit protein synthesis and viral replication. Viral RNAs were previously regarded as the primary ligands for cellular dsRNA sensors, however, cellular RNAs have recently been revealed to be major regulators of nucleic acid PAMP responses capable of inhibiting and promoting their activation. Though HSV1 is restricted by dsRNA-dependent antiviral effectors PKR and RNase L, what RNA activates these enzymes and the contribution of newly characterized cellular calibrators of these responses is completely unknown. Our overall objective is to understand how cellular RNAs contribute to antiviral immunity in HSV1 infection. DsRNA-dependent responses are counteracted by several HSV1-encoded proteins, underlining the importance of the task. These include vhs, an endoribonuclease which accelerates mRNA decay minimizing dsRNA accumulation and Us11, which binds dsRNA preventing activation of the eIF2α kinase PKR and RNase L. Our preliminary results indicate two opposing mechanisms exist by which cellular RNAs also regulate dsRNA-dependent cell intrinsic defenses in HSV1 infected cells. First, we hypothesize that cellular circular (circ) RNAs, protected from RNase L activation by Us11 and selectively preserved from vhs cleavage, inhibit PKR activation. Second, we hypothesize that HSV1-induced dsRNA is not exclusively virus-encoded and instead contains a cellular RNA component dependent on cytosolic DNA-sensing by cGAS-STING, the sensing pathway that induces type I interferon (IFN) in response to HSV1. This would constitute a novel mode of signal amplification and cross-talk between pathogenic DNA and RNA cytosolic detection systems. We will test these hypotheses in two specific aims that (i) determine the role of circRNAs in HSV1 infection biology; and (ii) define how the cGAS-STING dsDNA sensing pathway influences dsRNA abundance and/or antiviral dsRNA-dependent innate immune responses. Completion of these specific aims will reveal how cell intrinsic innate immune responses are regulated by host RNAs and parallel innate immune signaling pathways during infection with HSV1, a medically important human pathogen. The results of this exploratory study are potentially applicable to a wide variety of pathogenic human viruses and could reveal new strategies for treating virus infections. In addition, they will provide important insights into cross-talk between innate immune signaling pathways involving dsDNA and dsRNA that are important therapeutic targets for cancer and autoimmune disease.