Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is the ongoing global pandemic that poses substantial challenges to public health worldwide. A subset of COVID-19 patients experience systemic inflammatory response, known as cytokine storm, which may lead to death. Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) is an important mediator of inflammation and cell death. Here, we examined the interaction of RIPK1-mediated innate immunity with SARS-CoV-2 infection. We found evidence of RIPK1 activation in human COVID-19 lung pathological samples, and cultured human lung organoids and ACE2 transgenic mice infected by SARS-CoV-2. Inhibition of RIPK1 using multiple small-molecule inhibitors reduced the viral load of SARS-CoV-2 in human lung organoids. Furthermore, therapeutic dosing of the RIPK1 inhibitor Nec-1s reduced mortality and lung viral load, and blocked the CNS manifestation of SARS-CoV-2 in ACE2 transgenic mice. Mechanistically, we found that the RNA-dependent RNA polymerase of SARS-CoV-2, NSP12, a highly conserved central component of coronaviral replication and transcription machinery, promoted the activation of RIPK1. Furthermore, NSP12 323L variant, encoded by the SARS-CoV-2 C14408T variant first detected in Lombardy, Italy, that carries a Pro323Leu amino acid substitution in NSP12, showed increased ability to activate RIPK1. Inhibition of RIPK1 downregulated the transcriptional induction of proinflammatory cytokines and host factors including ACE2 and EGFR that promote viral entry into cells. Our results suggest that SARS-CoV-2 may have an unexpected and unusual ability to hijack the RIPK1-mediated host defense response to promote its own propagation and that inhibition of RIPK1 may provide a therapeutic option for the treatment of COVID-19.

由严重急性呼吸系统综合症冠状病毒 2 (SARS-CoV-2) 引起的 2019 年冠状病毒病 (COVID-19) 是持续不断的全球大流行病，对全球公共卫生构成重大挑战。一部分 COVID-19 患者会出现全身性炎症反应，称为细胞因子风暴，这可能会导致死亡。受体相互作用的丝氨酸/苏氨酸蛋白激酶 1 (RIPK1) 是炎症和细胞死亡的重要介质。在这里，我们检查了 RIPK1 介导的先天免疫与 SARS-CoV-2 感染的相互作用。我们在人类 COVID-19 肺病理样本、培养的人类肺类器官和感染 SARS-CoV-2 的 ACE2 转基因小鼠中发现了 RIPK1 激活的证据。使用多种小分子抑制剂抑制 RIPK1 可降低人肺类器官中 SARS-CoV-2 的病毒载量。此外，RIPK1抑制剂Nec-1s的治疗剂量降低了死亡率和肺病毒载量，并阻断了ACE2转基因小鼠中SARS-CoV-2的CNS表现。在机制上，我们发现 SARS-CoV-2 的 RNA 依赖性 RNA 聚合酶 NSP12 是冠状病毒复制和转录机制的高度保守的中心成分，促进了 RIPK1 的激活。此外，由在意大利伦巴第大区首次检测到的 SARS-CoV-2 C14408T 变体编码的 NSP12 323L 变体在 NSP12 中带有 Pro323Leu 氨基酸取代，显示出激活 RIPK1 的能力增强。抑制 RIPK1 会下调促炎细胞因子和宿主因子（包括促进病毒进入细胞的 ACE2 和 EGFR）的转录诱导。