Food Nutrition & Health Team, Food & Bio-based Products Group, AgResearch Grasslands, Palmerston North, New Zealand.
Riddet Institute, Massey University, Palmerston North, New Zealand.
Cell Microbiol. 2018 Feb;20(2). doi: 10.1111/cmi.12805. Epub 2017 Dec 6.
Inappropriate activation of intestinal innate immune receptors, such as toll-like receptors (TLRs), by pathogenic bacteria is linked to chronic inflammation. In contrast, a "tonic" level of TLR activation by commensal bacteria is required for intestinal homeostasis. A technical challenge when studying this activation in vitro is the co-culturing of oxygen-requiring mammalian cells with obligate anaerobic commensal bacteria. To overcome this, we used a novel apical anaerobic co-culture system to successfully adapt a TLR activation assay to be conducted in conditions optimised for both cell types. Live Faecalibacterium prausnitzii, an abundant obligate anaerobe of the colonic microbiota, induced higher TLR2 and TLR2/6 activation than the dead bacterium. This enhanced TLR induction by live F. prausnitzii, which until now has not previously been described, may contribute to maintenance of gastrointestinal homeostasis. This highlights the importance of using physiologically relevant co-culture systems to decipher the mechanisms of action of live obligate anaerobes.
肠道先天免疫受体（如 Toll 样受体 [TLRs]）被致病菌异常激活与慢性炎症有关。相比之下，共生菌对 TLR 的“基础”水平激活对于肠道稳态是必需的。在体外研究这种激活时，一个技术挑战是需要将需氧哺乳动物细胞与专性厌氧菌共生菌共培养。为了克服这一问题，我们使用了一种新型的顶端厌氧共培养系统，成功地使 TLR 激活测定法适应了两种细胞类型的最佳条件。活的普拉梭菌（Faecalibacterium prausnitzii）是结肠微生物群中丰富的专性厌氧菌，其诱导的 TLR2 和 TLR2/6 激活高于死菌。这种由活普拉梭菌引起的增强的 TLR 诱导作用以前没有被描述过，可能有助于维持胃肠道稳态。这突出了使用生理相关的共培养系统来解析活体专性厌氧菌作用机制的重要性。
