School of Medicine, The University of Adelaide, School of Medicine, The University of Adelaide, Adelaide, South Australia, Australia.
South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia.
Am J Physiol Gastrointest Liver Physiol. 2021 Apr 1;320(4):G506-G520. doi: 10.1152/ajpgi.00445.2020. Epub 2021 Jan 20.
The stem/progenitor cells of the developing intestine are biologically distinct from their adult counterparts. Here, we examine the microenvironmental cues that regulate the embryonic stem/progenitor population, focusing on the role of Notch pathway factor delta-like protein-1 (DLK1). mRNA-seq analyses of intestinal mesenchymal cells (IMCs) collected from embryonic day 14.5 (E14.5) or adult IMCs and a novel coculture system with E14.5 intestinal epithelial organoids were used. Following addition of recombinant DLK1 (rDLK) or siRNA (), epithelial characteristics were compared using imaging, replating efficiency assays, qPCR, and immunocytochemistry. The intestinal phenotypes of littermate and mice were compared using immunohistochemistry. Using transcriptomic analyses, we identified morphogens derived from the embryonic mesenchyme that potentially regulate the developing epithelial cells, to focus on Notch family candidate DLK1. Immunohistochemistry indicated that DLK1 was expressed exclusively in the intestinal stroma at E14.5 at the top of emerging villi, decreased after birth, and shifted to the intestinal epithelium in adulthood. In coculture experiments, addition of rDLK1 to adult IMCs inhibited organoid differentiation, whereas knockdown in embryonic IMCs increased epithelial differentiation to secretory lineage cells. mice had restricted Ki67 cells in the villi base and increased secretory lineage cells compared with embryos. Mesenchyme-derived DLK1 plays an important role in the promotion of epithelial stem/precursor expansion and prevention of differentiation to secretory lineages in the developing intestine. Using a novel coculture system, transcriptomics, and transgenic mice, we investigated differential molecular signaling between the intestinal epithelium and mesenchyme during development and in the adult. We show that the Notch pathway factor delta-like protein-1 (DLK1) is stromally produced during development and uncover a new role for DLK1 in the regulation of intestinal epithelial stem/precursor expansion and differentiation to secretory lineages.
发育中肠道的干细胞/祖细胞在生物学上与成年对应物不同。在这里，我们研究了调节胚胎干细胞/祖细胞群体的微环境线索，重点关注 Notch 途径因子 delta-like protein-1 (DLK1) 的作用。从胚胎第 14.5 天（E14.5）或成年 IMC 收集的肠间充质细胞（IMCs）的 mRNA-seq 分析和具有 E14.5 肠上皮类器官的新型共培养系统用于此。添加重组 DLK1 (rDLK) 或 siRNA () 后，使用成像、重铺效率测定、qPCR 和免疫细胞化学比较上皮特征。使用免疫组织化学比较同窝仔鼠和 小鼠的肠道表型。使用转录组分析，我们鉴定了可能调节发育中上皮细胞的来源于胚胎间充质的形态发生素，以聚焦于 Notch 家族候选物 DLK1。免疫组织化学表明，DLK1 仅在 E14.5 时在出现的绒毛顶部的肠基质中表达，出生后减少，并在成年时转移到肠上皮。在共培养实验中，向成年 IMC 添加 rDLK1 抑制类器官分化，而在胚胎 IMC 中敲低则增加上皮分化为分泌谱系细胞。与 胚胎相比， 小鼠的绒毛基部的 Ki67 细胞受限，分泌谱系细胞增加。间充质衍生的 DLK1 在促进发育中肠上皮干细胞/祖细胞的扩增和防止分化为分泌谱系中起重要作用。使用新型共培养系统、转录组学和转基因小鼠，我们研究了发育中和成年期间肠上皮和间充质之间的差异分子信号。我们表明 Notch 途径因子 delta-like protein-1 (DLK1) 在发育过程中由基质产生，并揭示了 DLK1 在调节肠上皮干细胞/祖细胞扩增和分化为分泌谱系中的新作用。
