包膜病毒进入宿主细胞需要病毒和宿主细胞膜的融合,从病毒包膜突出的病毒融合蛋白促进的过程。这些病毒融合蛋白需要由宿主因子触发,对于一些病毒,此事件发生在内体和/或溶酶体内。因此,这些“晚期穿透病毒”必须被内化并递送至有助于进入的细胞内囊泡。因为胞吞作用和囊泡运输是紧密调节的细胞过程,晚期穿透病毒还依赖于特定的宿主蛋白来有效递送到融合位点,这表明这些可以作为抗病毒治疗的目标。在这项研究中,我们研究了鞘氨醇激酶(SKs)在病毒进入中的作用,发现鞘氨醇激酶1(SK1)和/或SK2的化学抑制和SK1/2的敲减抑制了埃博拉病毒(EBOV)进入宿主细胞.机械上,抑制SK1/2阻止EBOV到达含有EBOV受体的晚期内体和溶酶体,尼曼选择C1(NPC1)。此外,我们提供的证据表明,由SK1/2抑制引起的运输缺陷独立于通过细胞表面S1P受体的鞘氨醇-1-磷酸(S1P)信号传导而发生.最后,我们发现SK1/2的化学抑制可以防止其他晚期穿透病毒的进入,包括沙粒病毒和冠状病毒,并抑制Huh7.5细胞中具有复制能力的EBOV和SARS-CoV-2的感染。总之,我们的结果强调了SK1/2在内吞运输中的重要作用,它可以靶向抑制晚期穿透病毒的进入,并可以作为开发广谱抗病毒疗法的起点。
Entry of enveloped viruses in host cells requires the fusion of viral and host cell membranes, a process that is facilitated by viral fusion proteins protruding from the viral envelope. These viral fusion proteins need to be triggered by host factors, and for some viruses, this event occurs inside endosomes and/or lysosomes. Consequently, these \'late-penetrating viruses\' must be internalized and delivered to entry-conducive intracellular vesicles. Because endocytosis and vesicular trafficking are tightly regulated cellular processes, late-penetrating viruses also depend on specific host proteins for efficient delivery to the site of fusion, suggesting that these could be targeted for antiviral therapy. In this study, we investigated a role for sphingosine kinases (SKs) in viral entry and found that chemical inhibition of sphingosine kinase 1 (SK1) and/or SK2 and knockdown of SK1/2 inhibited entry of Ebola virus (EBOV) into host cells. Mechanistically, inhibition of SK1/2 prevented EBOV from reaching late-endosomes and lysosomes that contain the EBOV receptor, Niemann Pick C1 (NPC1). Furthermore, we present evidence that suggests that the trafficking defect caused by SK1/2 inhibition occurs independently of sphingosine-1-phosphate (S1P) signaling through cell-surface S1P receptors. Lastly, we found that chemical inhibition of SK1/2 prevents entry of other late-penetrating viruses, including arenaviruses and coronaviruses, and inhibits infection by replication-competent EBOV and SARS-CoV-2 in Huh7.5 cells. In sum, our results highlight an important role played by SK1/2 in endocytic trafficking, which can be targeted to inhibit entry of late-penetrating viruses and could serve as a starting point for the development of broad-spectrum antiviral therapeutics.