Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
The Johns Hopkins Malaria Research Institute, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.
Insect Mol Biol. 2021 Apr;30(2):210-230. doi: 10.1111/imb.12689. Epub 2020 Dec 27.
Mosquitoes are the greatest animal threat to human health, causing hundreds of millions of infections and around 1 million deaths each year. All mosquito-borne pathogens must traverse the salivary glands (SGs) to be transmitted to the next host, making this organ an ideal target for interventions. The adult SG develops from precursor cells located in the larval SG duct bud. Characterization of the larval SG has been limited. We sought to better understand larval SG architecture, secretion and gene expression. We developed an optimized method for larval SG staining and surveyed hundreds of larval stage 4 (L4) SGs using fluorescence confocal microscopy. Remarkable variation in SG cell and chromatin organization differed among individuals and across the L4 stage. Lumen formation occurred during L4 stage through secretion likely involving a coincident cellular apical lipid enrichment and extracellular vesicle-like structures. Meta-analysis of microarray data showed that larval SG gene expression is divergent from adult SGs, more similar to larval gastric cecae, but different from other larval gut compartments. This work highlights the variable cell architecture of larval Anopheles gambiae SGs and provides candidate targets for genetic strategies aiming to disrupt SGs and transmission of mosquito-borne pathogens.
蚊子是对人类健康最大的动物威胁，每年导致数亿感染和约 100 万人死亡。所有通过蚊子传播的病原体都必须穿过唾液腺 (SGs) 才能传播到下一个宿主，这使得该器官成为干预的理想目标。成蚊的 SG 由位于幼虫 SG 导管芽中的前体细胞发育而来。对幼虫 SG 的特性研究一直受到限制。我们试图更好地了解幼虫 SG 的结构、分泌和基因表达。我们开发了一种优化的幼虫 SG 染色方法，并使用荧光共聚焦显微镜对数百个幼虫 4 期 (L4) SG 进行了调查。个体之间和 L4 期之间的 SG 细胞和染色质组织的显著变化存在差异。L4 期通过分泌形成腔，可能涉及细胞顶部分泌脂质的富集和细胞外囊泡样结构。微阵列数据分析的荟萃分析表明，幼虫 SG 的基因表达与成蚊 SG 不同，与幼虫胃盲囊更相似，但与其他幼虫肠道部位不同。这项工作突出了幼虫冈比亚按蚊 SG 的可变细胞结构，并为旨在破坏 SG 和传播蚊子传播的病原体的遗传策略提供了候选目标。
