Interactions Among Secretory Immunoglobulin A, CD71, and Transglutaminase-2 Affect Permeability of Intestinal Epithelial Cells to Gliadin Peptides
Interactions Among Secretory Immunoglobulin A, CD71, and Transglutaminase-2 Affect Permeability of Intestinal Epithelial Cells to Gliadin Peptides
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DOI：
10.1053/j.gastro.2012.05.051
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发表时间：
2012-09-01
期刊：
影响因子：
29.4
通讯作者：
Heyman, Martine
中科院分区：
文献类型：
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作者：
Lebreton, Corinne;Menard, Sandrine;Heyman, Martine
背景与目的：转铁蛋白受体（CD 71）在活动性乳糜泻患者的十二指肠活检样本中上调，并促进分泌性免疫球蛋白A（SIgA）-麦胶蛋白复合物的逆向转运。我们研究了过表达CD 71的肠上皮细胞系，以确定SIgA和CD 71之间的相互作用如何促进麦胶蛋白肽的跨上皮转运。方法：我们分析了8名成人和1名儿童活动性乳糜泻的十二指肠活检标本。Caco-2和HT 29 - 19 A上皮细胞系用针对CD 71的荧光标记的小干扰RNA转染。通过流式细胞术、免疫沉淀和共聚焦显微镜分析伊加、CD 71和转氨酶2（Tgase 2）之间的相互作用。在极化的Caco-2细胞单层中分析了SIgA-CD 71复合物的转胞吞作用和肠对麦胶蛋白3 H-p31 -49肽的渗透性。研究结果：使用荧光共振能量转移和原位邻近连接分析，我们观察到SIgA和CD 71或CD 71和Tgase 2之间的物理相互作用在活检样品和单层Caco-2细胞的肠上皮细胞的顶面。CD 71和Tgase 2与SIgA共沉淀，结合于Caco-2细胞表面。SIgA-CD 71复合物被内化并定位于早期内体和再循环隔室，但不在溶酶体中。在存在针对p31-49的腹腔伊加或SIgA的情况下，完整的3 H-p31 -49跨Caco-2单层的转运显著增加;这种转运被可溶性CD 71或Tgase 2抑制剂抑制。结论：在与顶端CD 71结合后，SIgA（有或没有麦胶蛋白肽）进入再循环途径并避免溶酶体降解;该过程允许结合肽的顶端-基底转胞吞作用。Tgase 2促进了这一机制，并可能参与了乳糜泻的发病机制。
BACKGROUND & AIMS: The transferrin receptor (CD71) is up-regulated in duodenal biopsy samples from patients with active celiac disease and promotes retrotransport of secretory immunolglobulin A (SIgA)-gliadin complexes. We studied intestinal epithelial cell lines that overexpress CD71 to determine how interactions between SIgA and CD71 promote transepithelial transport of gliadin peptides. METHODS: We analyzed duodenal biopsy specimens from 8 adults and 1 child with active celiac disease. Caco-2 and HT29-19A epithelial cell lines were transfected with fluorescence-labeled small interfering RNAs against CD71. Interactions among IgA, CD71, and transglutaminase 2 (Tgase2) were analyzed by flow cytometry, immunoprecipitation, and confocal microscopy. Transcytosis of SIgA-CD71 complexes and intestinal permeability to the gliadin 3H-p31-49 peptide were analyzed in polarized monolayers of Caco-2 cells. RESULTS: Using fluorescence resonance energy transfer and in situ proximity ligation assays, we observed physical interactions between SIgA and CD71 or CD71 and Tgase2 at the apical surface of enterocytes in biopsy samples and monolayers of Caco-2 cells. CD71 and Tgase2 were co-precipitated with SIgA, bound to the surface of Caco-2 cells. SIgA-CD71 complexes were internalized and localized in early endosomes and recycling compartments but not in lysosomes. In the presence of celiac IgA or SIgA against p31-49, transport of intact 3H-p31-49 increased significantly across Caco-2 monolayers; this transport was inhibited by soluble CD71 or Tgase2 inhibitors. CONCLUSIONS: Upon binding to apical CD71, SIgA (with or without gliadin peptides) enters a recycling pathway and avoids lysosomal degradation; this process allows apical-basal transcytosis of bound peptides. This mechanism is facilitated by Tgase2 and might be involved in the pathogenesis of celiac disease.