活性氧在血红蛋白β亚基诱导的抗病毒应答中的调控作用

Hemoglobin, the oxygen-carrying protein of vertebrates and many invertebrates, plays an important role in the resistance to invasion of pathogens and regulation of the innate immunity. Hemoglobin β-subunit (HB) is a main component of hemoglobin. Previously, we reported that the porcine HB was able to suppress the growth of classical swine fever virus (CSFV) via regulating the type I interferon pathway. Recently, we found that HBs from different animal species exert broad-spectrum antiviral effects. However, the underlying mechanisms remain elusive. Considering that hemoglobin is able to regulate the production of reactive oxygen species (ROS), which is a key factor for the host cell to trigger an efficient antiviral response mediated by type I interferon, we hypothesize that HB may have the ability to regulate ROS, which is a possible mediator of the HB-mediated antiviral response. In this proposal, we will reveal the role of ROS in the HB-triggered antiviral response mediated by type I interferon. Firstly, we will test whether HB can upregulate ROS production in response to viral infections using probes specific for ROS and the effects of HB on the expression of the genes related to oxidative stress response using a genome-wide transcriptome analysis. Secondly, we will verify the effects of the HB-induced ROS on the type I interferon pathway when ROS is altered by ROS scavengers or siRNAs. Thirdly, we will explore the effects of the HB-induced ROS on the antiviral response mediated by the type I interferon. This proposal is expected to reveal the regulatory function and the underlying mechanisms of HB as a novel universal antiviral factor.

血红蛋白是机体内重要的载氧蛋白，在抵抗病原体入侵、调控机体天然免疫中发挥着重要作用。血红蛋白β亚基（HB）是血红蛋白的重要组分。此前我们发现，猪源HB能通过调节I型干扰素抑制猪瘟病毒复制，且不同动物来源的HB都呈现较广谱的抗病毒作用。已知动物血红蛋白能促进活性氧（ROS）生成，而ROS能调节I型干扰素介导的抗病毒反应。据此我们推测，HB可能通过ROS来调节I型干扰素介导的抗病毒反应。本项目首先用针对ROS的荧光探针检测HB能否改变病毒感染细胞内的ROS水平，并通过转录组测序分析氧化应激反应相关基因表达的变化；然后，通过ROS抑制剂和RNA干扰等方法改变细胞内ROS水平，分析HB诱导的ROS对I型干扰素相关通路的调控作用，并检测HB诱导的ROS对病毒复制的影响。本项目有望揭示HB调控抗病毒天然免疫反应的一种新机制。

血红蛋白是机体内重要的载氧蛋白，在抵抗病原体入侵、调控机体天然免疫中发挥着重要作用。血红蛋白β亚基（HB）是血红蛋白的重要组分。本实验室此前研究发现，猪源HB（pHB）能通过RIG-I信号通路调节细胞I型干扰素的产生，从而拮抗猪瘟病毒在细胞内的增殖。我们也发现，不同动物来源的HB都具有一定的影响病毒复制的作用。而通过比较不同动物来源的HB与pHB之间的同源性发现，人源HB（hHB）与pHB同源性最高，因而，我们以hHB为主要目标，探索hHB在抗病毒天然免疫反应调控中的作用及相关机制。在本研究中，我们明确证实hHB能通过RIG-I和MDA5介导的信号通路对不同的RNA病毒复制产生不同的调节作用。通过进一步探索其相关调节机制发现，hHB通过直接阻碍MDA5-dsRNA互作来抑制MDA5介导的抗病毒天然免疫反应。已知动物血红蛋白能促进活性氧（ROS）生成，而ROS能调节I型干扰素介导的抗病毒反应。据此我们推测，HB可能通过ROS来调控病毒复制。而我们的研究中也确实发现，hHB能以ROS作为中介，间接地通过促进细胞内ROS累积促进RIG-I泛素化，进而增强RIG-I介导的抗病毒天然免疫反应。总之，我们的研究证明hHB是RIG-I/MDA5介导的抗病毒天然免疫反应的多效性调节因子，并揭示了细胞微环境中的氧化应激水平在抗病毒先天免疫的调节中的重要性。