Arthropod-borne viruses (arboviruses) such as dengue, Zika and chikungunya constitute a significant proportion of the global disease burden. The principal vector of these pathogens is the mosquito Aedes (Ae.) aegypti, and its ability to transmit virus to a human host is influenced by environmental factors such as temperature. However, exactly how ambient temperature influences virus replication within mosquitoes remains poorly elucidated, particularly at the molecular level. Here, we use chikungunya virus (CHIKV) as a model to understand how the host mosquito transcriptome responds to arbovirus infection under different ambient temperatures. We exposed CHIKV-infected mosquitoes to 18 oC, 28 oC and 32 oC, and found higher temperature correlated with higher virus replication levels, particularly at early time points post-infection. Lower ambient temperatures resulted in reduced virus replication levels. Using RNAseq, we found that temperature significantly altered gene expression levels in mosquitoes, particularly components of the immune response. The highest number of significantly differentially expressed genes in response to CHIKV was observed at 28 oC, with a markedly more muted effect observed at either lower (18 oC) or higher (32 oC) temperatures. At the higher temperature, the expression of many classical immune genes, including Dicer-2 in the RNAi pathway, was not substantially altered in response to CHIKV. Upregulation of Toll, IMD and JAK-STAT pathways was only observed at 28 oC. Time post infection also led to substantially different gene expression profiles, and this effect varied depending upon the which temperature mosquitoes were exposed to. Taken together, our data indicate temperature significantly modulates mosquito gene expression in response to infection, potentially leading to impairment of immune defences at higher ambient temperatures.

中文翻译：

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温度改变虫媒病毒感染期间蚊子的基因表达

节肢动物传播的病毒（虫媒病毒），例如登革热，寨卡病毒和基孔肯雅热，在全球疾病负担中占很大比例。这些病原体的主要载体是埃及伊蚊，其将病毒传播给人宿主的能力受温度等环境因素的影响。但是，确切的环境温度如何影响蚊子内的病毒复制尚不清楚，尤其是在分子水平上。在这里，我们使用基孔肯雅病毒（CHIKV）作为模型来了解宿主蚊子转录组在不同环境温度下如何响应虫媒病毒感染。我们将受CHIKV感染的蚊子暴露于18 oC，28 oC和32 oC，发现温度升高与病毒复制水平升高相关，尤其是在感染后的早期。较低的环境温度导致病毒复制水平降低。使用RNAseq，我们发现温度显着改变了蚊子中的基因表达水平，特别是免疫应答的组成部分。在28 oC时，观察到对CHIKV响应的显着差异表达基因的数量最多，而在较低（18 oC）或较高（32 oC）的温度下观察到的沉默作用明显更多。在较高的温度下，许多经典的免疫基因（包括Dicer-2）在RNAi途径中的表达并未因CHIKV的变化而发生实质性改变。仅在28 oC时观察到Toll，IMD和JAK-STAT通路上调。感染后的时间也导致基因表达谱的显着不同，并且这种影响根据蚊子所接触的温度而有所不同。在一起