Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32827, USA.
Viruses. 2020 Feb 25;12(3):253. doi: 10.3390/v12030253.
Resident cells in the skin serve as the first innate line of defense against insect-borne pathogens, but the role of these cell types in promoting or limiting arbovirus replication is not completely understood. Here, we have examined the outcome of infection of cultured human keratinocyte cells with La Crosse virus (LACV), using a spontaneously transformed cell line, HaCaT. In single cycle infections, keratinocyte HaCaT cells supported rapid and high level LACV replication, resulting in high virus yields and extensive caspase-dependent cell death. By contrast, multi-cycle LACV replication in HaCaT cells was restricted by an antiviral response elicited by the production of both IFN-β and IFN-λ. During low multiplicity LACV infections, HaCaT cell death was seen in non-infected bystander cells. Media from LACV-infected cells induced caspase-dependent killing of naïve non-infected HaCaT cells, and this bystander cell death was relieved by IFN-β neutralizing antibodies or by an inhibitor of JAK-STAT signaling. Naïve HaCaT cells showed dose-dependent killing by treatment with exogenous IFN-β but not IFN-λ. Our data suggest a model whereby keratinocytes produce IFNs which limit virus spread through both antiviral signaling and by induction of bystander cell death of potential new target cells for infection.
皮肤中的常驻细胞是抵御虫媒病原体的第一道先天防线，但这些细胞类型在促进或限制虫媒病毒复制方面的作用尚不完全清楚。在这里，我们使用自发转化的细胞系 HaCaT 研究了培养的人角质形成细胞感染拉克罗斯病毒 (LACV) 的结果。在单周期感染中，角质形成细胞 HaCaT 细胞支持快速和高水平的 LACV 复制，导致高病毒产量和广泛的半胱天冬酶依赖性细胞死亡。相比之下，HaCaT 细胞中的多周期 LACV 复制受到由 IFN-β 和 IFN-λ 的产生引发的抗病毒反应的限制。在低多重性 LACV 感染期间，在未感染的旁观者细胞中观察到 HaCaT 细胞死亡。来自 LACV 感染细胞的培养基诱导未感染的幼稚 HaCaT 细胞发生半胱天冬酶依赖性杀伤，而 IFN-β 中和抗体或 JAK-STAT 信号通路抑制剂可缓解旁观者细胞死亡。幼稚的 HaCaT 细胞通过用外源性 IFN-β 处理显示出剂量依赖性杀伤，但 IFN-λ 则不然。我们的数据表明，角蛋白细胞产生 IFN 的模型，通过抗病毒信号和诱导感染的潜在新靶细胞的旁观者细胞死亡来限制病毒的传播。
