Bonfini Alessandro, Liu Xi, Buchon Nicolas
Department of Entomology, Cornell University, Ithaca, NY 14853, USA.
Department of Entomology, Cornell University, Ithaca, NY 14853, USA.
Dev Comp Immunol. 2016 Nov;64:22-38. doi: 10.1016/j.dci.2016.02.008. Epub 2016 Feb 6.
The intestine acts as one of the interfaces between an organism and its external environment. As the primary digestive organ, it is constantly exposed to a multitude of stresses as it processes and absorbs nutrients. Among these is the recurring damage induced by ingested pathogenic and commensal microorganisms. Both the bacterial activity and immune response itself can result in the loss of epithelial cells, which subsequently requires replacement. In the Drosophila midgut, this regenerative role is fulfilled by intestinal stem cells (ISCs). Microbes not only trigger cell loss and replacement, but also modify intestinal and whole organism physiology, thus modulating ISC activity. Regulation of ISCs is integrated through a complex network of signaling pathways initiated by other gut cell populations, including enterocytes, enteroblasts, enteroendocrine and visceral muscles cells. The gut also receives signals from circulating immune cells, the hemocytes, to properly respond against infection. This review summarizes the types of gut microbes found in Drosophila, mechanisms for their elimination, and provides an integrated view of the signaling pathways that regulate tissue renewal in the midgut.
肠道是生物体与其外部环境之间的界面之一。作为主要的消化器官，它在处理和吸收营养物质时不断受到多种压力。其中包括摄入的致病微生物和共生微生物引起的反复损伤。细菌活性和免疫反应本身都可能导致上皮细胞的损失，随后需要进行替换。在果蝇中肠，这种再生作用由肠道干细胞（ISC）完成。微生物不仅引发细胞损失和替换，还会改变肠道和整个生物体的生理状态，从而调节ISC的活性。ISC的调节是通过由其他肠道细胞群体（包括肠细胞、成肠细胞、肠内分泌细胞和内脏肌肉细胞）启动的复杂信号通路网络来整合的。肠道还接收来自循环免疫细胞（血细胞）的信号，以对感染做出适当反应。本综述总结了果蝇中发现的肠道微生物类型、清除它们的机制，并提供了调节中肠组织更新的信号通路的综合观点。
