Pluripotent stem-cell-derived human intestinal organoids (HIOs) are three-dimensional, multicellular structures that model a naive intestinal epithelium in an in vitro system. Several published reports have investigated the use of HIOs to study host-microbe interactions. We recently demonstrated that microinjection of the nonpathogenic Escherichia coli strain ECOR2 into HIOs induced morphological and functional maturation of the HIO epithelium, including increased secretion of mucins and cationic antimicrobial peptides. In the current work, we use ECOR2 as a biological probe to further characterize the environment present in the HIO lumen. We generated an isogenic mutant in the general stress response sigma factor RpoS and employed this mutant to compare challenges faced by a bacterium during colonization of the HIO lumen relative to the germ-free mouse intestine. We demonstrate that the loss of RpoS significantly decreases the ability of ECOR2 to colonize HIOs, although it does not prevent colonization of germ-free mice. These results indicate that the HIO lumen is a more restrictive environment to E. coli than the germ-free mouse intestine, thus increasing our understanding of the HIO model system as it pertains to studying the establishment of intestinal host-microbe symbioses.

中文翻译：

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与无菌小鼠肠道相比，人类肠道类器官的内腔对细菌造成更大的压力：缺乏 RpoS 的大肠杆菌作为定植探针


多能干细胞衍生的人肠道类器官 (HIO) 是三维多细胞结构，可在体外系统中模拟幼稚肠上皮。几份已发表的报告研究了使用 HIO 来研究宿主-微生物相互作用。我们最近证明，将非致病性大肠杆菌菌株 ECOR2 显微注射到 HIO 中可诱导 HIO 上皮的形态和功能成熟，包括增加粘蛋白和阳离子抗菌肽的分泌。在当前的工作中，我们使用 ECOR2 作为生物探针来进一步表征 HIO 腔中存在的环境。我们在一般应激反应 σ 因子 RpoS 中产生了同基因突变体，并利用该突变体来比较细菌在 HIO 腔内定植期间相对于无菌小鼠肠道所面临的挑战。我们证明，RpoS 的丢失显着降低了 ECOR2 定植 HIO 的能力，尽管它并不能阻止无菌小鼠的定植。这些结果表明，与无菌小鼠肠道相比，HIO 腔对大肠杆菌来说是一个更具限制性的环境，从而增加了我们对 HIO 模型系统的理解，因为它涉及研究肠道宿主微生物共生体的建立。