Storm Rickard J, Persson B David, Skalman Lars Nygård, Frängsmyr Lars, Lindström Mona, Rankin Greg, Lundmark Richard, Domellöf Fatima Pedrosa, Arnberg Niklas
Division of Virology, Department of Clinical Microbiology, Umeå University, Umeå, Sweden.
Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden.
J Virol. 2017 Feb 14;91(5). doi: 10.1128/JVI.02019-16. Print 2017 Mar 1.
Epidemic keratoconjunctivitis (EKC) is a severe, contagious ocular disease that affects 20 to 40 million individuals worldwide every year. EKC is mainly caused by six types of human adenovirus (HAdV): HAdV-8, -19, -37, -53, -54, and -56. Of these, HAdV-8, -19, and -37 use sialic acid-containing glycans as cellular receptors. αVβ3, αVβ5, and a few additional integrins facilitate entry and endosomal release of other HAdVs. With the exception of a few biochemical analyses indicating that HAdV-37 can interact physically with αVβ5, little is known about the integrins used by EKC-causing HAdVs. Here, we investigated the overall integrin expression on human corneal cells and found expression of α2, α3, α6, αV, β1, and β4 subunits in human corneal epithelium and/or in a human corneal epithelial (HCE) cell line but no or less accessible expression of α4, α5, β3, or β5. We also identified the integrins used by HAdV-37 through a series of binding and infection competition experiments and different biochemical approaches. Together, our data suggest that HAdV-37 uses αVβ1 and α3β1 integrins for infection of human corneal epithelial cells. Furthermore, to confirm the relevance of these integrins in the HAdV-37 life cycle, we developed a corneal multilayer tissue system and found that HAdV-37 infection correlated well with the patterns of αV, α3, and β1 integrin expression. These results provide further insight into the tropism and pathogenesis of EKC-causing HAdVs and may be of importance for future development of new antiviral drugs. Keratitis is a hallmark of EKC, which is caused by six HAdV types (HAdV-8, -19, -37, -53, -54, and -56). HAdV-37 and some other HAdV types interact with integrin αVβ5 in order to enter nonocular human cells. In this study, we found that αVβ5 is not expressed on human corneal epithelial cells, thus proposing other host factors mediate corneal infection. Here, we first characterized integrin expression patterns on corneal tissue and corneal cells. Among the integrins identified, competition binding and infection experiments and biochemical assays pointed out αVβ1 and α3β1 to be of importance for HAdV-37 infection of corneal tissue. In the absence of a good animal model for EKC-causing HAdVs, we also developed an system with multilayer HCE cells and confirmed the relevance of the suggested integrins during HAdV-37 infection.
流行性角结膜炎（EKC）是一种严重的传染性眼部疾病，每年在全球影响2000万至4000万人。EKC主要由六种人类腺病毒（HAdV）引起：HAdV - 8、- 19、- 37、- 53、- 54和- 56。其中，HAdV - 8、- 19和- 37利用含唾液酸聚糖作为细胞受体。αVβ3、αVβ5和其他一些整合素促进其他HAdV的进入和内体释放。除了一些生化分析表明HAdV - 37可与αVβ5发生物理相互作用外，对于引起EKC的HAdV所使用的整合素知之甚少。在此，我们研究了人角膜细胞上整合素的整体表达情况，发现在人角膜上皮和/或人角膜上皮（HCE）细胞系中存在α2,、α3、α6、αV、β1和β4亚基的表达，但α−4、α−5、β−3或β−5无表达或表达难以检测到。我们还通过一系列结合和感染竞争实验以及不同的生化方法确定了HAdV - 37所使用的整合素。总之，我们的数据表明HAdV - 37利用αVβ1和α3β1整合素感染人角膜上皮细胞。此外，为了证实这些整合素在HAdV - 37生命周期中的相关性，我们开发了一种角膜多层组织系统，发现HAdV - 37感染与αV、α3和β1整合素的表达模式密切相关。这些结果为引起EKC的HAdV的嗜性和发病机制提供了进一步的见解，可能对新型抗病毒药物的未来开发具有重要意义。角膜炎是EKC的一个标志，它由六种HAdV类型（HAdV - 8、- 19、- 37、- 53、- 54和- 56）引起。HAdV - 37和其他一些HAdV类型与整合素αVβ5相互作用以便进入非眼部人类细胞。在本研究中，我们发现αVβ5在人角膜上皮细胞上不表达，因此提出其他宿主因子介导角膜感染。在此，我们首先对角膜组织和角膜细胞上的整合素表达模式进行了表征。在所鉴定的整合素中，竞争结合和感染实验以及生化分析指出αVβ1和α3β1对HAdV - 37感染角膜组织很重要。在缺乏针对引起EKC的HAdV的良好动物模型的情况下，我们还开发了一种多层HCE细胞系统，并证实了所建议的整合素在HAdV - 37感染过程中的相关性。
