Division of Dermatology, Department of Medicine, David Geffen School of Medicine at University of California (UCLA), Los Angeles, CA, United States.
Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States.
Front Immunol. 2023 Dec 15;14:1284148. doi: 10.3389/fimmu.2023.1284148. eCollection 2023.
The COVID-19 pandemic has highlighted the need to identify mechanisms of antiviral host defense against SARS-CoV-2. One such mediator is interferon-g (IFN-γ), which, when administered to infected patients, is reported to result in viral clearance and resolution of pulmonary symptoms. IFN-γ treatment of a human lung epithelial cell line triggered an antiviral activity against SARS-CoV-2, yet the mechanism for this antiviral response was not identified.
Given that IFN-γ has been shown to trigger antiviral activity via the generation of nitric oxide (NO), we investigated whether IFN-γ induction of antiviral activity against SARS-CoV-2 infection is dependent upon the generation of NO in human pulmonary epithelial cells. We treated the simian epithelial cell line Vero E6 and human pulmonary epithelial cell lines, including A549-ACE2, and Calu-3, with IFN-γ and observed the resulting induction of NO and its effects on SARS-CoV-2 replication. Pharmacological inhibition of inducible nitric oxide synthase (iNOS) was employed to assess the dependency on NO production. Additionally, the study examined the effect of interleukin-1b (IL-1β) on the IFN-g-induced NO production and its antiviral efficacy.
Treatment of Vero E6 cells with IFN-γ resulted in a dose-responsive induction of NO and an inhibitory effect on SARS-CoV-2 replication. This antiviral activity was blocked by pharmacologic inhibition of iNOS. IFN-γ also triggered a NO-mediated antiviral activity in SARS-CoV-2 infected human lung epithelial cell lines A549-ACE2 and Calu-3. IL-1β enhanced IFN-γ induction of NO, but it had little effect on antiviral activity.
Given that IFN-g has been shown to be produced by CD8+ T cells in the early response to SARS-CoV-2, our findings in human lung epithelial cell lines, of an IFN-γ-triggered, NO-dependent, links the adaptive immune response to an innate antiviral pathway in host defense against SARS-CoV-2. These results underscore the importance of IFN-γ and NO in the antiviral response and provide insights into potential therapeutic strategies for COVID-19.
COVID-19 大流行凸显了识别针对 SARS-CoV-2 的抗病毒宿主防御机制的必要性。干扰素-γ (IFN-γ) 就是这样一种介质，据报道，当将其施用于感染患者时，可导致病毒清除和肺部症状缓解。IFN-γ 处理人肺上皮细胞系可引发针对 SARS-CoV-2 的抗病毒活性，但这种抗病毒反应的机制尚未确定。
鉴于 IFN-γ 已被证明通过生成一氧化氮 (NO) 来触发抗病毒活性，我们研究了 IFN-γ 诱导的针对 SARS-CoV-2 感染的抗病毒活性是否依赖于人肺上皮细胞中 NO 的生成。我们用 IFN-γ 处理猿猴上皮细胞系 Vero E6 和人肺上皮细胞系，包括 A549-ACE2 和 Calu-3，并观察到由此产生的 NO 诱导及其对 SARS-CoV-2 复制的影响。使用诱导型一氧化氮合酶 (iNOS) 的药理学抑制剂来评估对 NO 生成的依赖性。此外，该研究还研究了白细胞介素-1b (IL-1β) 对 IFN-γ 诱导的 NO 产生及其抗病毒功效的影响。
IFN-γ 处理 Vero E6 细胞可导致 NO 剂量依赖性诱导，并抑制 SARS-CoV-2 复制。这种抗病毒活性被 iNOS 的药理学抑制所阻断。IFN-γ 还在感染 SARS-CoV-2 的人肺上皮细胞系 A549-ACE2 和 Calu-3 中引发了一种由 NO 介导的抗病毒活性。IL-1β 增强了 IFN-γ 诱导的 NO 产生，但对抗病毒活性影响不大。
鉴于 IFN-γ 已被证明可在 SARS-CoV-2 早期被 CD8+T 细胞产生，我们在人肺上皮细胞系中的发现，IFN-γ 触发的、NO 依赖性的，将适应性免疫反应与宿主防御针对 SARS-CoV-2 的先天抗病毒途径联系起来。这些结果强调了 IFN-γ 和 NO 在抗病毒反应中的重要性，并为 COVID-19 的潜在治疗策略提供了见解。
