Data_Sheet_1_Nrf2 Negatively Regulates Type I Interferon Responses and Increases Susceptibility to Herpes Genital Infection in Mice.PDF

Herpes simplex virus-2 (HSV-2) is a leading cause of sexually transmitted infections for which no effective vaccines or prophylactic treatment currently exist. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor involved in the detoxification of reactive oxygen species (ROS) and has been more recently shown to regulate inflammatory and antiviral responses. Here, we evaluated the importance of Nrf2 in the control of HSV-2 genital infection, and its role in the regulation of HSV-induced innate antiviral immunity. Comparison of antiviral gene expression profile by RNA-sequencing analysis of wild type and Nrf2-mutant (Nrf2AY/AY) murine macrophages showed an upregulation at the basal level of the type I interferon-associated gene network. The same basal increased antiviral profile was also observed in the spleen of Nrf2−/− mice. Interestingly, the lack of Nrf2 in murine cells was sufficient to increase the responsiveness to HSV-derived dsDNA and protect cells from HSV-2 infection in vitro. Surprisingly, there was no indication of an alteration in STING expression in murine cells as previously reported in cells of human origin. Additionally, genetic activation of Nrf2 in Keap1−/− mouse embryonic fibroblasts increased HSV-2 infectivity and replication. Finally, using an in vivo vaginal herpes infection model, we showed that Nrf2 controlled early innate immune responses to HSV-2 without affecting STING expression levels. Nrf2−/− mice exhibited reduced viral replication that was associated with higher level of type I interferons in vaginal washes. Nrf2−/− mice also displayed reduced weight loss, lower disease scores, and higher survival rates than wild type animals. Collectively, these data identify Nrf2 as a negative regulator of the interferon-driven antiviral response to HSV-2 without impairing STING mRNA and protein expression levels in murine cells.

单纯疱疹病毒2型（Herpes simplex virus-2, HSV-2）是性传播感染的主要致病原，目前尚无有效的疫苗或预防性治疗方案。核因子红细胞2相关因子2（Nuclear factor erythroid 2-related factor 2, Nrf2）是一类参与活性氧（reactive oxygen species, ROS）解毒过程的转录因子，近年研究证实其还可调控炎症与抗病毒免疫应答。本研究评估了Nrf2在控制HSV-2生殖道感染中的作用，以及其在调控HSV诱导的天然抗病毒免疫中的功能。通过对野生型与Nrf2突变型（Nrf2AY/AY）小鼠巨噬细胞进行RNA测序（RNA-sequencing）分析，比较二者的抗病毒基因表达谱，结果显示I型干扰素相关基因网络的基础表达水平显著上调。同样，在Nrf2敲除（Nrf2−/−）小鼠的脾脏组织中，也观察到了基础抗病毒基因表达升高的现象。有趣的是，小鼠细胞中Nrf2的缺失足以增强其对HSV来源双链DNA（double-stranded DNA, dsDNA）的应答能力，并在体外实验中使细胞免受HSV-2感染。令人意外的是，此前在人类细胞中报道的干扰素基因刺激因子（Stimulator of Interferon Genes, STING）表达改变现象，在小鼠细胞中并未出现相关迹象。此外，在Kelch样ECH关联蛋白1（Kelch-like ECH-associated protein 1, Keap1）敲除（Keap1−/−）小鼠胚胎成纤维细胞中，Nrf2的基因激活会增强HSV-2的感染性与复制能力。最后，通过体内阴道疱疹感染模型，本研究证实Nrf2可调控机体对HSV-2的早期天然免疫应答，且不会影响STING的表达水平。Nrf2敲除小鼠的病毒复制水平更低，其阴道灌洗液中的I型干扰素水平也更高。与野生型小鼠相比，Nrf2敲除小鼠的体重减轻程度更轻、疾病评分更低，存活率也更高。综上，本研究数据表明，Nrf2是介导干扰素驱动的抗HSV-2抗病毒应答的负调控因子，且不会影响小鼠细胞中STING的mRNA与蛋白表达水平。