Barillas-Mury Carolina, de Carvalho Stephanie, McNich Colton, Barletta Ana
National Institutes of Health.
Res Sq. 2025 Jul 29:rs.3.rs-7151993. doi: 10.21203/rs.3.rs-7151993/v1.
The mosquito fat body plays key roles in metabolism and immunity, yet its cellular diversity and functional specialization remain unclear. We characterized the Anopheles gambiae fat body and associated cells, examining their responses to blood feeding, bacterial infection, and immune priming following infection, at single-cell resolution. We analyzed 97,650 nuclei from the female mosquito's abdominal body wall and identified seven major cell types. Fat body trophocytes were the most abundant (~ 85% of cells), while sessile hemocytes represented 7.4% of cells. Trophocytes consisted of five subpopulations, including basal (T1, T2), metabolic-enriched (T3), immune-responsive (T4), and a vitellogenic population (T5) exclusive to blood-fed females. T4 trophocytes exhibited constitutive expression of immune genes, while multiple cell types, including other trophocytes, hemocytes, and epidermal epithelial cells, responded to a systemic bacterial challenge. Oenocytes (1.1% of cells) induced the expression of enzymes involved in the biosynthesis of lipids in response to immune priming. Blood feeding triggered massive transcriptomic changes, with a strong induction of vitellogenin and multiple genes involved in DNA replication, consistent with trophocyte endoreplication and metabolic reprogramming. Interestingly, vitellogenin mRNA was expressed only in the first layer of trophocytes facing the hemolymph and had an apical subcellular localization. These findings provide a high-resolution atlas of fat body and associated cells, revealing specialized roles in immunity and reproduction and offering insights into how mosquitoes coordinate metabolic and immune functions at the cellular level.
蚊子的脂肪体在新陈代谢和免疫中发挥着关键作用，但其细胞多样性和功能特化仍不清楚。我们对冈比亚按蚊的脂肪体及相关细胞进行了表征，以单细胞分辨率研究了它们对血液摄取、细菌感染以及感染后的免疫激发的反应。我们分析了来自雌性蚊子腹部体壁的97,650个细胞核，鉴定出七种主要细胞类型。脂肪体营养细胞最为丰富（约占细胞总数的85%），而固定血细胞占细胞总数的7.4%。营养细胞由五个亚群组成，包括基础亚群（T1、T2）、富含代谢功能的亚群（T3）、免疫反应性亚群（T4）以及仅存在于吸血雌性蚊子中的卵黄生成亚群（T5）。T4营养细胞表现出免疫基因的组成型表达，而多种细胞类型，包括其他营养细胞、血细胞和表皮上皮细胞，对全身性细菌攻击均有反应。卵泡细胞（占细胞总数的1.1%）在免疫激发后诱导参与脂质生物合成的酶的表达。血液摄取引发了大规模的转录组变化，强烈诱导了卵黄蛋白原以及多个参与DNA复制的基因的表达，这与营养细胞的核内复制和代谢重编程一致。有趣的是，卵黄蛋白原mRNA仅在面向血淋巴的第一层营养细胞中表达，并且具有顶端亚细胞定位。这些发现提供了一份脂肪体及相关细胞的高分辨率图谱，揭示了它们在免疫和繁殖中的特殊作用，并为蚊子如何在细胞水平上协调代谢和免疫功能提供了见解。
