Janus kinase inhibitors (JAKis) represent a new strategy in rheumatoid arthritis (RA) therapy. Still, data directly comparing different JAKis are rare. In the present in vitro study, we investigated the immunomodulatory potential of four JAKis (tofacitinib, baricitinib, upadacitinib, and filgotinib) currently approved for RA treatment by the European Medicines Agency. Increasing concentrations of JAKi or methotrexate, conventionally used in RA therapy, were either added to freshly mitogen-stimulated or preactivated peripheral blood mononuclear cells (PBMC), isolated from healthy volunteers. A comparable, dose-dependent inhibition of lymphocyte proliferation was observed in samples treated with tofacitinib, baricitinib, and upadacitinib, while dosage of filgotinib had to be two orders of magnitude higher. In contrast, antiproliferative effects were strongly attenuated when JAKi were added to preactivated PBMCs. High dosage of upadacitinib and filgotinib also affected cell viability. Further, analyses of DNA double-strand break markers γH2AX and 53BP1 indicated an enhanced level of DNA damage in cells incubated with high concentrations of filgotinib and a dose-dependent reduction in clearance of radiation-induced γH2AX foci in the presence of tofacitinib or baricitinib. Thereby, our study demonstrated a broad comparability of immunomodulatory effects induced by different JAKi and provided first indications, that (pan)JAKi may impair DNA damage repair in irradiated PBMCs.

中文翻译：

---

不同的JAK抑制剂和甲氨蝶呤对淋巴细胞增殖和DNA损伤的影响

Janus激酶抑制剂（JAKis）代表类风湿关节炎（RA）治疗的新策略。但是，直接比较不同JAKis的数据仍然很少。在目前的体外研究中，我们调查了目前由欧洲药品管理局批准用于RA治疗的四种JAKis（托法替尼，巴利替尼，upadacitinib和filgotinib）的免疫调节潜力。传统上用于RA治疗的JAKi或甲氨蝶呤的浓度增加到从健康志愿者身上分离的新鲜促有丝分裂原刺激或预活化的外周血单核细胞（PBMC）中。在用tofacitinib，baricitinib和upadacitinib处理的样品中观察到了相当的剂量依赖性的淋巴细胞增殖抑制作用，而filgotinib的剂量必须高两个数量级。相比之下，当将JAKi添加到预活化的PBMC中时，抗增殖作用会大大减弱。高剂量的upadacitinib和filgotinib也影响细胞活力。此外，对DNA双链断裂标记γH2AX和53BP1的分析表明，在存在托法替尼或baricitinib的情况下，与高浓度的filgotinib孵育的细胞中DNA损伤的水平提高，并且辐射诱导的γH2AX灶清除率呈剂量依赖性降低。因此，我们的研究证明了由不同的JAKi诱导的免疫调节作用具有广泛的可比性，并提供了第一个迹象，即（pan）JAKi可能会损害辐照的PBMC中的DNA损伤修复。DNA双链断裂标记γH2AX和53BP1的分析表明，在存在托法替尼或baricitinib的情况下，与高浓度的filgotinib孵育的细胞中DNA损伤的水平增强，并且辐射诱导的γH2AX灶清除率呈剂量依赖性降低。因此，我们的研究证明了由不同的JAKi诱导的免疫调节作用具有广泛的可比性，并提供了第一个迹象，即（pan）JAKi可能会损害辐照的PBMC中的DNA损伤修复。DNA双链断裂标记γH2AX和53BP1的分析表明，在存在托法替尼或baricitinib的情况下，与高浓度的filgotinib孵育的细胞中DNA损伤的水平增强，并且辐射诱导的γH2AX灶清除率呈剂量依赖性降低。因此，我们的研究证明了由不同的JAKi诱导的免疫调节作用具有广泛的可比性，并提供了第一个迹象，即（pan）JAKi可能会损害辐照的PBMC中的DNA损伤修复。