Toll-like receptor 2-mediated peptidoglycan uptake by immature intestinal epithelial cells from apical side and exosome-associated transcellular transcytosis.
Toll-like receptor 2-mediated peptidoglycan uptake by immature intestinal epithelial cells from apical side and exosome-associated transcellular transcytosis.
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DOI：
10.1002/jcp.21985
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发表时间：
2010-03
影响因子：
5.6
通讯作者：
Tan, Xiao-Di
中科院分区：
文献类型：
--
作者：
Bu, Heng-Fu;Wang, Xiao;Tang, Yi;Koti, Viola;Tan, Xiao-Di
肽聚糖是一种从细菌细胞壁中提取的有效免疫佐剂。以前的研究表明，肠上皮可以从管腔吸收肽聚糖。尽管如此，肽聚糖是如何被吸收并穿过肠道上皮的，在很大程度上仍不清楚。在这里，我们首先使用IEC-18和HT29-CL19A细胞研究了肽聚糖的体外转运，这两种细胞代表了肠隐窝中不太成熟的上皮细胞。在荧光显微镜下，我们观察到肠细胞对双标记肽聚糖的内化。研究发现，被包埋的肽聚糖与肽聚糖识别蛋白-3形成了一种复合体，这可能有助于在体内传递肽聚糖。利用电子显微镜，我们揭示了顶端肽聚糖通过肠上皮单层的摄取参与了吞噬、多囊泡体的形成和外切体的分泌。我们还利用Transwell系统研究了肽聚糖的转运。我们的数据表明HT29-CL19A细胞将顶端负载的肽聚糖与外切体一起排出到基底外侧室。含有肽聚糖的碱侧外切体萃取物可诱导巨噬细胞活化。通过给小鼠灌胃标记的肽聚糖，我们发现腔内的肽聚糖被小肠隐窝中的柱状上皮细胞摄取。此外，我们还发现融合前未成熟但融合后成熟的C2BBe1细胞通过Toll样受体2依赖的方式吞噬肽聚糖。综上所述，我们的发现表明：(1)以隐窝为基础的未成熟肠上皮细胞在腔多糖通过肠上皮的运输中起重要作用；(2)腔多糖通过Toll样受体2特异性的吞噬-多囊体体-外体途径跨肠上皮转运。被吸收的肽聚糖及其衍生物可能有助于维持肠道免疫平衡。
Peptidoglycan is a potent immune adjuvant derived from bacterial cell walls. Previous investigations suggest that intestinal epithelium may absorb peptidoglycan from the lumen. Nonetheless, how peptidoglycan is taken up and crosses intestinal epithelium remains largely unclear. Here, we first characterized peptidoglycan transport in vitro using IEC-18 and HT29-CL19A cells, which represent less mature epithelial cells in intestinal crypts. With fluorescent microscopy, we visualized internalization of dual-labeled peptidoglycan by enterocytes. Engulfed peptidoglycan was found to form a complex with peptidoglycan recognition protein-3, which may facilitate delivering peptidoglycan in vivo. Utilizing electronic microscopy, we revealed that uptake of apical peptidoglycan across intestinal epithelial monolayers was involved in phagocytosis, multivesicular body formation, and exosome secretion. We also studied transport of peptidoglycan using the transwell system. Our data indicated that apically loaded peptidoglycan was exocytosed to the basolateral compartment with exosomes by HT29-CL19A cells. The peptidoglycan-contained basolateral exosome extracts induced macrophage activation. Through gavaging mice with labeled peptidoglycan, we found that luminal peptidoglycan was taken up by columnar epithelial cells in crypts of the small intestine. Furthermore, we showed that pre-confluent immature but not post-confluent mature C2BBe1 cells engulfed peptidoglycan via a toll-like receptor 2-dependent manner. Together, our findings suggest that (1) crypt-based immature intestinal epithelial cells play an important role in transport of luminal peptidoglycan over the intestinal epithelium; and (2) luminal peptidoglycan is transcytosed across intestinal epithelia via a toll-like receptor 2-meciated phagocytosis-multivesicular body-exosome pathway. The absorbed peptidoglycan and its derivatives may facilitate maintenance of intestinal immune homeostasis.
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影响因子：
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作者：
CHENG, H;LEBLOND, CP
通讯作者：
LEBLOND, CP
影响因子：
3.1
作者：
LICHTMAN, SN;KEKU, J;SARTOR, RB
通讯作者：
SARTOR, RB
影响因子：
4.4
作者：
Neal, Matthew D.;Leaphart, Cynthia;Hackam, David J.
通讯作者：
Hackam, David J.
影响因子：
29.4
作者：
Mallegol, Julia;Van Niel, Guillaume;Heyman, Martine
通讯作者：
Heyman, Martine
影响因子：
3.1
作者：
Dziarski, R;Gupta, D
通讯作者：
Gupta, D