Primary intestinal myofibroplast transcriptomic profiles upon the LPS stimulation vs PBS controls across embryonic development (E14.5) and adulthood.

The intestinal stroma provides a microenvironment for immune cells activation. Upregulated Toll-like receptor 4 (TLR4) in the intestinal epithelium is has key roles in necrotizing enterocolitis among premature infants. However, the involvement of stroma in excessive inflammation is yet to be investigated. To characterize the immature stroma, intestinal stromal cells were collected from the small intestines of embryonic day 14.5 (E14.5) and adult mice and treated with lipopolysaccharide and a global mRNA sequence analysis of differentially expressed transcripts was performed. TLR4 was expressed at lower levels in embryonic stromal cells than adult. CD14 expressed in flow CD11b+CD45+ stromal cells was identified as a key inducer for TLR mediated inflammatory signals. Embryonic stroma induced differentiation of monocytes into a higher proportion of CD11bhighCD11chigh mononuclear phagocytes (MPs), which have lower CD103 expression than adult stoma. Co-culture of inflamed embryonic stroma with LPS induced increased phagocytotic activity of MPs, which was markedly reduced following CD14 knock down. In summary, the immature intestinal stroma hyper activates inflammatory signals through CD14, producing a high proportion of CD11bhighCD11chigh MPs, which could lead to subsequent aberrant immune activation. Overall design: We compared primary intestinal myofibroplast transcriptomic profiles upon the LPS stimulation vs PBS controls across embryonic development (E14.5) and adulthood.

肠道间质为免疫细胞活化提供微环境。肠道上皮中上调的Toll样受体4（Toll-like receptor 4, TLR4）在早产儿坏死性小肠结肠炎中发挥关键作用。然而，间质是否参与过度炎症反应仍有待阐明。为表征未成熟肠道间质，本研究从胚胎第14.5天（embryonic day 14.5, E14.5）及成年小鼠的小肠中分离肠道间质细胞，经脂多糖（lipopolysaccharide, LPS）处理后，对差异表达转录本开展全转录组mRNA测序分析。结果显示，胚胎间质细胞中TLR4的表达水平低于成年小鼠间质细胞。经流式分选得到的CD11b+CD45+间质细胞中表达的CD14被鉴定为TLR介导炎症信号的关键诱导因子。胚胎间质可诱导单核细胞分化为更高比例的CD11b^highCD11c^high单核吞噬细胞（mononuclear phagocytes, MPs），这类细胞的CD103表达水平低于成年间质来源的MPs。将炎症活化的胚胎间质与LPS共培养可增强MPs的吞噬活性，而CD14敲低后该吞噬活性显著降低。综上，未成熟肠道间质可通过CD14过度激活炎症信号通路，产生高比例的CD11b^highCD11c^high MPs，进而引发后续的异常免疫活化。实验设计：本研究对比了胚胎发育阶段（E14.5）与成年阶段的原代肠道肌成纤维细胞在LPS刺激与PBS对照条件下的转录组谱差异。