Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China.
Insect Molecular Genetics and Biotechnology, National Centre for Scientific Research Demokritos, Institute of Biosciences and Applications, Athens, Greece.
J Immunol. 2023 Jul 1;211(1):140-153. doi: 10.4049/jimmunol.2300007.
The fat body plays a central role in the regulation of the life cycle of insects and acts as the major site for detoxification, nutrient storage, energy metabolism, and innate immunity. However, the diversity of cell types in the fat body, as well as how these cell subsets respond to virus infection, remains largely unknown. We used single-nucleus RNA sequencing to identify 23 distinct clusters representing adipocyte, hemocyte, epithelial cell, muscle cell, and glial cell types in the fat body of silkworm larvae. Further, by analysis of viral transcriptomes in each cell subset, we reveal that all fat body cells could be infected by Bombyx mori nucleopolyhedrovirus (BmNPV) at 72 h postinfection, and that the majority of infected cells carried at least a medium viral load, whereas most cells infected by BmNPV at 24 h postinfection had only low levels of infection. Finally, we characterize the responses occurring in the fat body cell clusters on BmNPV infection, which, on one hand, mainly reduce their metabolic functions, involving energy, carbohydrates, lipids, and amino acids, but, on the other hand, initiate a strong antiviral response. Our single-nucleus RNA sequencing analysis reveals the diversity of insect fat body cells and provides a resource of gene expression profiles for a systems-level understanding of their response to virus infection.
脂肪体在昆虫的生命周期调节中起着核心作用，是解毒、营养储存、能量代谢和先天免疫的主要场所。然而，脂肪体中细胞类型的多样性，以及这些细胞亚群如何对病毒感染做出反应，在很大程度上仍不清楚。我们使用单细胞 RNA 测序技术，在蚕幼虫的脂肪体中鉴定出 23 个不同的簇，代表脂肪细胞、血细胞、上皮细胞、肌肉细胞和神经胶质细胞类型。此外，通过对每个细胞亚群中的病毒转录组进行分析，我们揭示了所有脂肪体细胞在感染后 72 小时都可能被家蚕核型多角体病毒（BmNPV）感染，并且大多数感染细胞携带至少中等病毒载量，而在感染后 24 小时感染 BmNPV 的大多数细胞仅具有低水平的感染。最后，我们对脂肪体细胞簇在 BmNPV 感染时发生的反应进行了表征，一方面，这些反应主要降低了它们的代谢功能，涉及能量、碳水化合物、脂质和氨基酸，但另一方面，它们引发了强烈的抗病毒反应。我们的单细胞 RNA 测序分析揭示了昆虫脂肪体细胞的多样性，并为系统水平理解它们对病毒感染的反应提供了基因表达谱的资源。
