Transcriptomic analysis of differential gene expression reveals an increase in COX2 levels during in vitro canine herpesvirus infection

ABSTRACT: Canine herpesvirus (CaHV-1) affects canids worldwide, causing death in neonates and immunosuppressed hosts. Acute infection by CaHV-1 can cause reproductive, respiratory, and neurological problems in adult animals. Viral pathogenesis and host genes expressions during of CaHV-1infection are not clearly understood. In the present study, the transcriptome of canine kidney cell Mardin-Darby (MDCK) infected in vitro with canine herpesvirus was explored. For this, RNA sequencing (RNA-seq) of the samples in different moments during infection was carried out. Subsequently, the transcriptomic analysis genes related to cell activities and process involved to viral cycle infection were evaluated until 32h post-inoculation (pi). Among evaluated genes, was verified a significant and gradative increase of the prostaglandin-endoperoxide synthase 2 (PTGS2) or cyclooxygenase 2 (COX2) gene expression, throughout of infection, though differential gene expression analysis and validated by quantitative reverse transcription PCR (RT-qPCR). High COX2 expression is usually induced in response to inflammation, pathogens or activation of the immune system but can be a viral mechanism to favor viral replication. Thus, COX2 level increase can be a favorable factor for viral infection with Cahv-1 virus and the use of selective COX2 inhibitors may be beneficial for limiting the infection or clinical signs by causing interruption of the viral replication cycle during active infection. Additionally, the regulation genes expression differential verified in this study can contribute to determining important targets for inhibiting canine herpesvirus infection either by cellular or viral mechanisms.

摘要：犬疱疹病毒1型（Canine herpesvirus 1, CaHV-1）在全球范围内感染犬科动物，可导致新生幼犬与免疫抑制宿主死亡。该病毒的急性感染还可引发成年动物出现生殖系统、呼吸系统及神经系统病症。目前学界对CaHV-1感染过程中的病毒致病机制与宿主基因表达调控机制尚未完全阐明。本研究针对体外感染犬疱疹病毒1型的犬肾细胞Mardin-Darby（MDCK）的转录组展开探究。为此，本研究对感染过程中不同时间点的样本进行了RNA测序（RNA sequencing, RNA-seq）。随后，本研究针对感染起始至接种后32小时（post-inoculation, pi）期间、与细胞活动及病毒感染周期相关的基因开展转录组分析。在本次分析的基因中，通过差异基因表达分析证实，环氧合酶2（cyclooxygenase 2, COX2，又称前列腺素内过氧化物合酶2 prostaglandin-endoperoxide synthase 2, PTGS2）的基因表达水平在整个感染过程中呈现显著且逐步升高的趋势，并通过定量反转录聚合酶链反应（quantitative reverse transcription PCR, RT-qPCR）完成了验证。正常情况下，COX2高表达由炎症、病原体刺激或免疫系统激活所诱导，但也可能是病毒促进自身复制的一种调控机制。由此可见，COX2表达上调可能是促进CaHV-1感染的有利因素，而使用选择性COX2抑制剂可通过阻断活跃感染期的病毒复制周期，从而助力限制病毒感染及其临床症状。此外，本研究中鉴定得到的差异表达调控基因，可为通过宿主细胞或病毒靶点抑制犬疱疹病毒感染的研究提供关键靶标参考。