Cell：巨噬细胞通过限制真菌产物的吸收来维持上皮的完整性

研究描述了一种机制，通过该机制，先天免疫系统可以对吸收的液体进行快速质量检查，从而避免结肠细胞中毒。这种机制依赖于远端结肠巨噬细胞群，这些巨噬细胞在上皮细胞中装有“气球样”突起（BLP），可对吸收的液体进行采样。在没有巨噬细胞或BLP的情况下，上皮细胞会不断吸收含有真菌产物的液体，从而导致其死亡并随后丧失上皮屏障完整性。

这些结果揭示了巨噬细胞在维持体内稳态中，结肠-微生物群相互作用的出乎意料的重要作用。

据悉，结肠主要负责吸收液体。它含有大量的微生物，包括真菌，在其远端部分富集。因此，结肠粘膜必须严格调节体液流入以控制真菌代谢产物的吸收，真菌代谢产物可能对上皮细胞有毒并导致屏障功能障碍。如何实现这一点仍然未知。

附：英文原文

Title: Macrophages Maintain Epithelium Integrity by Limiting Fungal Product Absorption

Author: Aleksandra S. Chikina, Francesca Nadalin, Mathieu Maurin, Mabel San-Roman, Thibault Thomas-Bonafos, Xin V. Li, Sonia Lameiras, Sylvain Baulande, Sandrine Henri, Bernard Malissen, Livia Lacerda Mariano, Jorge Barbazan, J. Magarian Blander, Iliyan D. Iliev, Danijela Matic Vignjevic, Ana-Maria Lennon-Duménil

Issue&Volume: 2020-09-23

Abstract: The colon is primarily responsible for absorbing fluids. It contains a large numberof microorganisms including fungi, which are enriched in its distal segment. The colonicmucosa must therefore tightly regulate fluid influx to control absorption of fungalmetabolites, which can be toxic to epithelial cells and lead to barrier dysfunction.How this is achieved remains unknown. Here, we describe a mechanism by which the innateimmune system allows rapid quality check of absorbed fluids to avoid intoxicationof colonocytes. This mechanism relies on a population of distal colon macrophagesthat are equipped with “balloon-like” protrusions (BLPs) inserted in the epithelium,which sample absorbed fluids. In the absence of macrophages or BLPs, epithelial cellskeep absorbing fluids containing fungal products, leading to their death and subsequentloss of epithelial barrier integrity. These results reveal an unexpected and essentialrole of macrophages in the maintenance of colon-microbiota interactions in homeostasis.

DOI: 10.1016/j.cell.2020.08.048

Source: https://www.cell.com/cell/fulltext/S0092-8674(20)31090-4