Sustained Wolbachia-mediated blocking of dengue virus isolates following serial passage in Aedes aegypti cell culture
Sustained Wolbachia-mediated blocking of dengue virus isolates following serial passage in Aedes aegypti cell culture
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DOI：
10.1093/ve/vez012
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发表时间：
2019-01-01
期刊：
影响因子：
5.3
通讯作者：
McGraw, Elizabeth A.
中科院分区：
文献类型：
--
作者：
Koh, Cassandra;Audsley, Michelle D.;McGraw, Elizabeth A.
沃尔巴克氏体是昆虫的细胞内共生体，可抑制节肢动物宿主中一系列病原体的复制。将沃尔巴克氏体释放到野生蚊子种群中是一项创新的生物防治措施，旨在抑制节肢动物传播的病毒（虫媒病毒）向人类传播，尤其是登革热病毒。基于沃尔巴克氏体的方法的成功取决于“病原体阻断”效应的稳定持续，但其机制基础尚不清楚。有证据表明，沃尔巴克氏体可能通过竞争宿主资源和激活宿主免疫来影响病毒复制。对沃尔巴克氏体的抵抗力的进化以及蚊子或病毒中病原体的阻断可以减少共生体释放对公共健康的影响。在这里，我们研究登革热 3 病毒 (DENV-3) 是否能够积累适应性突变，从而在 Wolbachia wMel 感染的细胞中连续传代期间提高其复制能力。在传代过程中，与对照组相比，沃尔巴克氏体感染细胞中的病毒分离株表现出更大的病毒载量变化。由于沃尔巴克氏体携带的阻断作用，这些分离株的病毒载量在传代过程中迅速下降，其中一些病毒全部消失，其余的则恢复到较低但稳定的水平。我们试图对幸存的传代分离株的基因组进行测序，但由于其丰度较低，无法获得足够的覆盖深度进行进化分析。相比之下，无沃尔巴克氏体对照细胞中的病毒载量在传代过程中始终较高。即使在无沃尔巴克氏体的细胞中，在沃尔巴克氏体存在下传代的存活分离株也表现出复制能力降低。这些实验证明了登革热在进化对沃尔巴克氏体介导的阻断的抗性方面面临的挑战。
Wolbachia is an intracellular endosymbiont of insects that inhibits the replication of a range of pathogens in its arthropod hosts. The release of Wolbachia into wild populations of mosquitoes is an innovative biocontrol effort to suppress the transmission of arthropod-borne viruses (arboviruses) to humans, most notably dengue virus. The success of the Wolbachia-based approach hinges upon the stable persistence of the 'pathogen blocking' effect, whose mechanistic basis is poorly understood. Evidence suggests that Wolbachia may affect viral replication via a combination of competition for host resources and activation of host immunity. The evolution of resistance against Wolbachia and pathogen blocking in the mosquito or the virus could reduce the public health impact of the symbiont releases. Here, we investigate if dengue 3 virus (DENV-3) is capable of accumulating adaptive mutations that improve its replicative capacity during serial passage in Wolbachia wMel-infected cells. During the passaging regime, viral isolates in Wolbachia-infected cells exhibited greater variation in viral loads compared to controls. The viral loads of these isolates declined rapidly during passaging due to the blocking effects of Wolbachia carriage, with several being lost all together and the remainder recovering to low but stable levels. We attempted to sequence the genomes of the surviving passaged isolates but, given their low abundance, were unable to obtain sufficient depth of coverage for evolutionary analysis. In contrast, viral loads in Wolbachia-free control cells were consistently high during passaging. The surviving isolates passaged in the presence of Wolbachia exhibited a reduced ability to replicate even in Wolbachia-free cells. These experiments demonstrate the challenge for dengue in evolving resistance to Wolbachia-mediated blocking.