Fitzmeyer Emily A, Dutt Taru S, Pinaud Silvain, Graham Barb, Gallichotte Emily N, Hill Jessica L, Campbell Corey L, Ogg Hunter, Howick Virginia, Lawniczak Mara K N, Osborne Nishimura Erin, Merkling Sarah Hélène, Henao-Tamayo Marcela, Ebel Gregory D
Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA.
MIVEGEC, Université de Montpellier, IRD, CNRS, Montpellier, France.
bioRxiv. 2024 Nov 24:2024.07.23.603613. doi: 10.1101/2024.07.23.603613.
The mosquito midgut functions as a key interface between pathogen and vector. However, studies of midgut physiology and virus infection dynamics are scarce, and in - an extremely efficient vector of West Nile virus (WNV) - nonexistent. We performed single-cell RNA sequencing on midguts, defined multiple cell types, and determined whether specific cell types are more permissive to WNV infection. We identified 20 cell states comprising 8 distinct cell types, consistent with existing descriptions of and midgut physiology. Most midgut cell populations were permissive to WNV infection. However, there were higher levels of WNV RNA (vRNA) in enteroendocrine cells, suggesting enhanced replication in this population. In contrast, proliferating intestinal stem cells (ISC) had the lowest levels of vRNA, a finding consistent with studies suggesting ISC proliferation in the midgut is involved in infection control. ISCs were also found to have a strong transcriptional response to WNV infection; genes involved in ribosome structure and biogenesis, and translation were significantly downregulated in WNV-infected ISC populations. Notably, we did not detect significant WNV-infection induced upregulation of canonical mosquito antiviral immune genes (e.g., , , etc.) at the whole-midgut level. Rather, we observed a significant positive correlation between immune gene expression levels and vRNA load in individual cells, suggesting that within midgut cells, high levels of vRNA may trigger antiviral responses. Our findings establish a midgut cell atlas, and provide insight into midgut infection dynamics of WNV by characterizing cell-type specific enhancement/restriction of, and immune response to, infection at the single-cell level.
蚊子的中肠是病原体与载体之间的关键界面。然而，关于中肠生理学和病毒感染动态的研究却很匮乏，而对于作为西尼罗河病毒（WNV）极其高效的载体——[此处可能缺失蚊子种类名称]而言，此类研究根本不存在。我们对[此处可能缺失蚊子种类名称]的中肠进行了单细胞RNA测序，确定了多种细胞类型，并判断特定细胞类型是否对WNV感染更具易感性。我们识别出了由8种不同细胞类型组成的20种细胞状态，这与[此处可能缺失蚊子种类名称]和[此处可能缺失蚊子种类名称]中肠生理学的现有描述一致。大多数中肠细胞群体对WNV感染具有易感性。然而，肠内分泌细胞中的WNV RNA（vRNA）水平更高，这表明该群体中的病毒复制增强。相比之下，增殖的肠道干细胞（ISC）的vRNA水平最低，这一发现与表明中肠中ISC增殖参与感染控制的研究一致。我们还发现ISC对WNV感染有强烈的转录反应；在WNV感染的ISC群体中，参与核糖体结构和生物发生以及翻译的基因显著下调。值得注意的是，在整个中肠水平上，我们未检测到WNV感染诱导的典型蚊子抗病毒免疫基因（如[此处可能缺失基因名称]、[此处可能缺失基因名称]等）的显著上调。相反，我们观察到单个细胞中免疫基因表达水平与vRNA载量之间存在显著正相关，这表明在中肠细胞内，高水平的vRNA可能触发抗病毒反应。我们的研究结果建立了一个[此处可能缺失蚊子种类名称]中肠细胞图谱，并通过在单细胞水平上表征感染的细胞类型特异性增强/限制以及免疫反应，深入了解了WNV的中肠感染动态。
