Institute of Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
Veterinary Centre for Resistance Research (TZR), Freie Universität Berlin, Berlin, Germany.
PLoS Negl Trop Dis. 2023 Aug 14;17(8):e0011554. doi: 10.1371/journal.pntd.0011554. eCollection 2023 Aug.
The South African bont tick Amblyomma hebraeum is a hematophagous vector for the heartwater disease pathogen Ehrlichia ruminantium in southern Africa. During feeding, the tick's enterocytes express proteins that perform vital functions in blood digestion, including proteins that may be involved in E. ruminantium acquisition, colonization or immunity. To delineate the molecular mechanism of midgut response to E. ruminantium infection, we performed comparative analyses of midgut transcriptomes of E. ruminantium infected engorged A. hebraeum nymphs, and infected adult male and female ticks with their corresponding matched uninfected controls, before and during feeding. A total of 102,036 unigenes were annotated in public databases and their expression levels analyzed for engorged nymphs as well as unfed and partly-fed adult ticks. There were 2,025 differentially expressed genes (DEGs) in midguts, of which 1,225 unigenes were up-regulated and 800 unigenes were down-regulated in the midguts of infected ticks. Annotation of DEGs revealed an increase in metabolic and cellular processes among E. ruminantium infected ticks. Notably, among the infected ticks, there was up-regulation in the expression of genes involved in tick immunity, histone proteins and oxidative stress responses. We also observed up-regulation of glycoproteins that E. ruminantium could potentially use as docking sites for host cell entry. Insights uncovered in this study offer a platform for further investigations into the molecular interaction between E. ruminantium and A. hebraeum.
南非钝缘蜱（Amblyomma hebraeum）是南部非洲引起心水病的病原体无形体（Ehrlichia ruminantium）的血吸式传播媒介。在吸血过程中，蜱的肠细胞会表达对血液消化至关重要的蛋白，其中可能包括与无形体的获取、定植或免疫有关的蛋白。为了阐明中肠对无形体感染的分子反应机制，我们对感染并饱血的南非钝缘蜱若虫、感染的成年雌雄蜱及其相应的未感染对照进行了中肠转录组的比较分析，分别在吸血前和吸血过程中进行。在公共数据库中注释了 102,036 个基因，并分析了饱血若虫以及未进食和部分进食的成年蜱的表达水平。在中肠中有 2,025 个差异表达基因（DEGs），其中感染蜱的中肠中有 1,225 个上调和 800 个下调的基因。DEGs 的注释显示，感染无形体的蜱中代谢和细胞过程增加。值得注意的是，在感染的蜱中，与蜱免疫、组蛋白和氧化应激反应相关的基因表达上调。我们还观察到与无形体可能用于宿主细胞进入的附着位点相关的糖蛋白表达上调。本研究揭示的见解为进一步研究无形体与南非钝缘蜱之间的分子相互作用提供了平台。
