Supplementary Material for: Differential Effect of JAK1/2 and TYK2 Inhibitors on Type III Interferon Induced Antiviral Defence in Human Intestinal Epithelial Cells

Introduction: Many cytokines, acting via Janus kinase (JAK)/tyrosine kinase 2 (TYK2)/signal transducer and activator of transcription (STAT) signalling pathways, are critical mediators of pathology in immune-mediated inflammatory diseases (IMIDs). Therefore, drugs that inhibit JAKs and TYKs (JAKis) have gained traction as effective treatment options for IMIDs. However, a common side effect of JAKis is increased risk of viral infection. Type I and III interferon (IFN) signal via JAK1 and TYK2. Type III IFNs protect mucosal membranes, including the intestinal barrier, from viral infection and type I IFNs prevent systemic viral spread. Methods: The human cell lines Caco-2 and HT-29 were used to investigate the impact of currently approved JAKis, baricitinib (JAK1/2 inhibitor) and deucravacitinib (TYK2 inhibitor), on type I and III IFN signalling and antiviral defence of intestinal epithelial cells (IECs). Results: Using concentrations commonly used for in vitro studies on IFNs, we found that attenuation of IFN-mediated antiviral defence in IECs is a mechanism that could contribute to the increased risk of viral infections associated with JAKis. However, when we examined clinically relevant drug concentrations, we found that while both drugs blocked the type I IFN response, type III IFN-induced antiviral immunity was less affected during TYK2 inhibition (deucravacitinib) compared to JAK1/2 inhibition (baricitinib). Conclusions: Our studies suggest that in treating diseases associated with excessive cytokine production (e.g., type I IFNs, interleukin (IL)-6, and IL-23), a TYK2 inhibitor may be preferable over a JAK1/2 inhibitor. This preference arises as the TYK2 inhibitor can effectively block the activity of proinflammatory and tissue-damaging cytokines (e.g., type I IFNs), while having less negative impact on the intestine’s ability to respond to type III IFN, thereby enabling it to enter an antiviral state.

引言：诸多细胞因子通过贾纳斯激酶（Janus kinase，JAK）/酪氨酸激酶2（tyrosine kinase 2，TYK2）/信号转导与转录激活因子（signal transducer and activator of transcription，STAT）信号通路发挥作用，是免疫介导性炎症疾病（immune-mediated inflammatory diseases，IMIDs）病理进程的关键介导因子。因此，靶向抑制JAK与TYK的药物（JAK抑制剂，JAKis）已成为免疫介导性炎症疾病的有效治疗选择，获得了广泛关注。然而，JAK抑制剂的常见不良反应之一是病毒感染风险升高。I型和III型干扰素（interferon，IFN）通过JAK1与TYK2进行信号转导：III型干扰素可保护包括肠屏障在内的黏膜屏障免受病毒感染，而I型干扰素可阻断全身性病毒播散。
方法：本研究使用人类细胞系Caco-2与HT-29，探究当前获批的JAK抑制剂巴瑞替尼（JAK1/2抑制剂）与氘可来昔替尼（TYK2抑制剂）对肠上皮细胞（intestinal epithelial cells，IECs）的I型、III型干扰素信号通路及抗病毒防御功能的影响。
结果：采用干扰素体外实验中常用的药物浓度进行检测时，我们发现肠上皮细胞中干扰素介导的抗病毒防御功能减弱，这一机制可能是JAK抑制剂相关病毒感染风险升高的原因之一。而在检测临床相关药物浓度时，尽管两种药物均可阻断I型干扰素应答，但与JAK1/2抑制（巴瑞替尼）相比，TYK2抑制（氘可来昔替尼）对III型干扰素诱导的抗病毒免疫的影响更弱。
结论：本研究结果提示，在治疗伴随细胞因子过度产生的疾病（如I型干扰素、白细胞介素6（interleukin，IL-6）与IL-23相关疾病）时，TYK2抑制剂或许优于JAK1/2抑制剂。这一优势源于TYK2抑制剂可有效阻断促炎且致组织损伤的细胞因子（如I型干扰素）的活性，同时对肠上皮响应III型干扰素的能力产生的负面影响更小，从而使肠道得以维持抗病毒状态。