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Regulation of cellular trafficking and pathogenesis by mucins

粘蛋白对细胞运输和发病机制的调节

基本信息

批准号：
07407063
负责人：
IRIMURA Tatsuro
金额：
$ 25.41万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1998
项目状态：
已结题

项目摘要

The aims of this proposal was to elucidate the biological roles of mucins in a variety of pathogenic processes focusing on their involvement in cellular recognition and trafficking. Epithelial mucins were investigated for their distribution, their biosynthetic regulation, and the mechanism of recognition by carbohydrate binding molecules (lectins). The importance of such recognition processes in cancer invasion and metastasis, allergic dermatitis, and other diseases was investigated. Important findings are listed herein : (1) A unique carbohydrate epitope in human colonic sulfomucin was identified as sulfo-LeィイD1aィエD1(HSOィイD23ィエD2-Galβ1-3[Fucα1-4]GlcNAc-). Mucins with this epitope, presumably MUC5B was found associated with gallstone in humans. Positional localization of mucins with this epitope was very similar between humans and mice as far as in the intestinal tracts. (2) The initial step of glycosylation of MUC2 mucin was investigated focusing on the maximum number and the order of … More GalNAc incorporation into multiple threonine residues. When a microsomal fraction of LS174T human colon carcinoma cells was used as a source of the enzyme, GalNAc incorporation was 100% to consecutive threonine residues whereas 〜50% to alternating threonine residues. Three recombinant UDP-GalNAc : peptide/N-acetylgalactosaminyltransferases (ppGalNAc-T1, T2, and T3) were tested for their capacity to transfer GalNAc into three consecutive threonine residues, the order and the maximum number was unique to each enzyme. (3) Recombinant human macrophage galactose/N-acetylgalactosamine-specific calcium-type lectin (hMGL) was tested for its interaction with MUC2 mucin peptides with various arrangement of attached GalNAc residues. hMGL, forming a trimeric configuration, was shown to preferentially bind MUC2 peptides with GalNAc on consecutive threonines. (4) A mucin-like high-molecular-weight and heavily glycosylated molecule was identified to be associated with mouse ovarian tumor OV2944 HM-1 cells. This molecule was recognized by a mouse macrophage C-type lectin (mMGL). OV2944 HM-1 variant cells selected for low mMGL binding, deficient in this cell surface mucin, were more metastatic to lymph nodes when injected subcutaneously into syngeneic mice. (5) Migration of mMGL positive dermal macrophages from the skin to lymph nodes were observed during the sensitization phase of contact dermatitis. Although mucins were already identified as one of natural ligands of mMGL, whether such a molecule in lymph nodes is involved in macrophage trafficking remains to be elucidated. Less

该提案的目的是阐明粘蛋白在各种致病过程中的生物学作用，重点是它们参与细胞识别和运输。研究了上皮粘蛋白的分布、生物合成调节以及糖结合分子（凝集素）的识别机制。研究了这种识别过程在癌症侵袭和转移、过敏性皮炎和其他疾病中的重要性。（1）在人结肠硫粘蛋白中发现了一个独特的糖表位，命名为硫代亮氨酸D1 α-GlcNAc D1（HSO亮氨酸D23-GlcNAc D2-Galβ1-3[Fucα1-4]GlcNAc-）。具有该表位的粘蛋白，推测为MUC 5 B，被发现与人类胆结石相关。粘蛋白与此表位的位置定位是非常相似的人类和小鼠之间的肠道。(2)研究了MUC 2粘蛋白糖基化的初始步骤，重点是MUC 2粘蛋白糖基化的最大数目和顺序。 ...更多信息 GalNAc掺入多个苏氨酸残基。当LS 174 T人结肠癌细胞的微粒体部分被用作酶的来源时，GalNAc掺入100%到连续的苏氨酸残基，而100%到交替的苏氨酸残基。三种重组UDP-GalNAc：测试肽/N-乙酰半乳糖胺转移酶（ppGalNAc-T1、T2和T3）将GalNAc转移到三个连续的苏氨酸残基中的能力，顺序和最大数目对于每种酶是独特的。(3)测试了重组人巨噬细胞半乳糖/N-乙酰半乳糖胺特异性钙型凝集素（hMGL）与具有各种连接的GalNAc残基排列的MUC 2粘蛋白肽的相互作用。形成三聚体构型的hMGL显示优先结合MUC 2肽与连续苏氨酸上的GalNAc。(4)一种粘蛋白样高分子量和高度糖基化的分子被鉴定为与小鼠卵巢肿瘤OV 2944 HM-1细胞相关。该分子被小鼠巨噬细胞C型凝集素（mMGL）识别。选择低mMGL结合的OV 2944 HM-1变体细胞（缺乏该细胞表面粘蛋白），当皮下注射到同基因小鼠中时，对淋巴结的转移性更大。(5)在接触性皮炎的致敏阶段，观察到mMGL阳性真皮巨噬细胞从皮肤迁移至淋巴结。虽然粘蛋白已被鉴定为mMGL的天然配体之一，但淋巴结中的这种分子是否参与巨噬细胞的运输仍有待阐明。少