ABSTRACT

The yellow fever mosquito Aedes aegypti is an obligatory blood feeder and a major arboviral disease vector, evoking severe public health concerns worldwide. In adult female mosquitoes, the gut is critical for blood digestion and pathogen entry. We aimed for a systematic exploration of microRNA expression dynamics in the gut during the gonadotrophic cycle. Small RNA libraries were constructed from female mosquito gut tissues at five time points. Unsupervised hierarchical clustering revealed three expression clusters (early, mid and late) peaking at sequential time points – 24, 48 and 72 h posteclosion. Differentially expressed miRNAs were identified at 24 h post-blood meal (PBM). Depletions of Methoprene-tolerant [Met; the juvenile hormone (JH) receptor] and Ecdysone receptor [EcR; the receptor to 20-hydroxyecdysone (20E)] were performed using dsRNA to these genes to investigate impacts on microRNA expressions. Our results suggest that Met-mediated signalling downregulates miRNA expression from the early cluster and upregulates that from the late cluster. EcR signalling either up- or downregulated miRNA levels at 24 h PBM, indicating a differential effect of this receptor in miRNA gene expression. Furthermore, miR-281, which is the most abundant miRNA in the gut tissue, is induced and repressed by Met- and EcR-mediated signalling, respectively. Systematic depletion using synthetic antagomir and phenotype examinations indicate that miR-281 is obligatory for the normal progression of blood digestion, ovarian development and reproduction. Collectively, this study unveils expression dynamics of microRNAs in the female gut tissue during the gonadotrophic cycle and demonstrates that they are affected by JH and 20E signalling.

摘要

黄热病蚊子埃及伊蚊是一种强制性的输血者和主要的虫媒病毒病媒介，在全世界引起了严重的公共卫生问题。在成年雌性蚊子中，肠道对于血液消化和病原体进入至关重要。我们旨在系统探索促性腺激素周期期间肠道中的 microRNA 表达动态。在五个时间点从雌性蚊子肠道组织构建小 RNA 文库。无监督的层次聚类揭示了三个表达簇（早期、中期和晚期）在连续时间点达到峰值——24、48 和 72 小时后闭合。在血餐后 24 小时 (PBM) 鉴定出差异表达的 miRNA。耐甲氧戊二烯的消耗[Met; 保幼激素 (JH) 受体] 和蜕皮激素受体 [EcR; 使用 dsRNA 对这些基因进行 20-羟基蜕皮激素受体 (20E)]，以研究对 microRNA 表达的影响。我们的结果表明，Met 介导的信号传导下调早期簇的 miRNA 表达并上调晚期簇的 miRNA 表达。EcR 信号在 24 小时 PBM 上调或下调 miRNA 水平，表明该受体在 miRNA 基因表达中的不同作用。此外，作为肠道组织中最丰富的 miRNA，miR-281 分别被 Met 和 EcR 介导的信号传导诱导和抑制。使用合成 antagomir 进行系统性耗竭和表型检查表明 miR-281 是血液消化、卵巢发育和生殖的正常进展所必需的。集体，