A zebrafish model of Ifih1-driven Aicardi-Goutières syndrome reproduces the interferon signature and the exacerbated inflammation of patients. A zebrafish model of Ifih1-driven Aicardi-Goutières syndrome reproduces the interferon signature and the exacerbated inflammation of patients

Type I Interferonopathies are a heterogenic group of rare diseases associated with an increase of type I interferon (IFN). The main challenge for the study of Type I interferonopathies is the lack of a well-founded animal model in which better characterize the phenotype as well as to perform fast and large drug screenings to offer the best treatment options. In this study, we report the development of a transgenic zebrafish model of Type I interferonopathy overexpressing ifih1 carrying the mutation p.Arg742His (Tg(ifih1_mut)), corresponding to the human mutation p.Arg779His. RNA sequence analysis from Tg(ifih1_mut) larvae revealed a systemic inflammation and IFN signature upon a suboptimal poly I:C induction compared with wild type larvae, confirming the phenotype observed in patients suffering from Type I interferonopathies. More interestingly, the phenotype was manifested in the zebrafish inflammation and Type I IFN reporters nfkb:eGFP and isg15:eGFP, respectively, making this zebrafish model suitable for future high throughput chemical screening (HTS). Using the unique advantages of the zebrafish model for gene editing we have generated Tg(ifih1_mut) knocked down for mavs and ikbke, that completely abrogated the Poly I:C induction and activation of the GFP of the reporters. Finally, we used an FDA approved drug, Baricitinib (Jak1/Jak2 inhibitor), which was able to reduce the inflammation and the ISGs expression. Our results demonstrate the potential of this model to further understand AGS pathological mechanisms and to identify novel therapeutic drugs by HTS. Overall design: To investigate the difference in the gene expression between zebrafish larvae control vs Tg(ifih1_mut) with and without Poly I:C stimulation, we sent to analyze 3dpf larvae of each group by RNAseq.

I型干扰素病（Type I Interferonopathies）是一类异质性罕见病，与I型干扰素（type I interferon, IFN）水平升高密切相关。目前该类疾病研究面临的核心挑战在于，缺乏成熟可靠的动物模型以精准表征其表型，同时无法开展快速大规模药物筛选以优化治疗方案。
本研究构建了过表达携带p.Arg742His突变的ifih1基因的I型干扰素病转基因斑马鱼模型（Tg(ifih1_mut)），该突变对应人类的p.Arg779His突变。对Tg(ifih1_mut)幼虫进行RNA测序（RNAseq）分析发现，与野生型幼虫相比，在亚最优剂量聚肌胞苷酸（poly I:C）诱导下，该模型呈现全身性炎症及干扰素特征性表达谱，验证了I型干扰素病患者的临床表型。更值得关注的是，该模型的表型可分别通过斑马鱼炎症报告基因系nfkb:eGFP与I型干扰素报告基因系isg15:eGFP得以显现，表明此斑马鱼模型可用于未来的高通量药物筛选（high throughput chemical screening, HTS）。
利用斑马鱼模型在基因编辑方面的独特优势，我们构建了mavs与ikbke基因敲低的Tg(ifih1_mut)模型，该模型可完全阻断聚肌胞苷酸诱导的报告基因GFP激活。最后，我们使用了美国食品药品监督管理局（Food and Drug Administration, FDA）批准的药物巴瑞替尼（Baricitinib，Jak1/Jak2抑制剂），该药物可有效减轻炎症反应并下调干扰素刺激基因（ISGs）的表达。本研究结果证实了该模型在进一步阐明AGS发病机制及通过高通量筛选发现新型治疗药物方面的应用潜力。
实验设计：为探究对照组与Tg(ifih1_mut)转基因斑马鱼幼虫在聚肌胞苷酸刺激与未刺激状态下的基因表达差异，我们对各组3天受精后（3 days post fertilization, 3dpf）的幼虫进行了RNA测序分析。