Globotriaosyl Ceramide (Gb3/CD77) in Burkitt's Lymphoma

Globottriosyl Ceramide (Gb3/CD77) 在伯基特淋巴瘤中的应用

• 批准号: 7204123
• 负责人: MARK D MALONEY
• 金额: $ 17.57万
• 依托单位: SPELMAN COLLEGE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7204123
• 关键词: B lymphocyte; Burkitt' s lymphoma; apoptosis; binding sites; biological signal transduction; cell growth regulation; cell line; cell population study; cell surface receptors; cellular pathology; ceramides; chemical structure function; computer simulation; cysteine endopeptidases; cytochrome c; flow cytometry; gene expression; genetic regulation; glycosphingolipids; intermolecular interaction; molecular oncology; neoplastic cell; receptor binding; shiga toxin

Verotoxins (VT's, also called Shiga toxins) produced by E. coli serotype 0157:H7 and other serotypes have been implicated as causative agents of hemolytic uremic syndrome, hemorrhagic colitis, and thrombocytopenic purpura. The receptors for VT's are globotriaosyl ceramide (Gb3 or CD77) and possibly other glycosphingolipids which contain Gal alpha1-4 Gal residues. Gb3 is expressed at the germinal center stage of B lymphocyte development. Because of their phenotypic resemblance, Daudi cells and other Burkitt's lymphoma-derived cell lines serve as in vitro models of GC B lymphocytes. The Gb3-binding VT B subunits mimic the IFNAR-1 subunit of the interferon-alpha receptor, the B cell protein CD19, and MHC class II proteins in their amino acid sequences. Experimental evidence to date indicates that Gb3 and Gb3-binding proteins are essential components of a number of signal transduction pathways in Burkitt's lymphoma and GC B lymphocytes. These include a role for Gb3/IFNAR-1 in IFN-alpha induced growth inhibition and adhesion, Gb3/CD19 interaction in adhesion and Gb3/VT B-subunit interaction in the induction of apoptosis. However, there is relatively little data available concerning which signal transduction pathways require Gb3, or the precise role of Gb3 in the pathways leading to the observed responses. Our preliminary investigations indicate that Gb3 may play a major role in a number of apoptotic pathways in Gb3-positive B cells. We propose to further investigate the role of Gb3 in signal transduction relating to apoptosis using the Daudi cell line, which expresses high levels of Gb3, and the Daudi-derived Gb3-deficient VT500 cell line. The long term objectives of the proposed research are to determine the cellular functions of Gb3 and other Gal alpha 1-4 Galcontaining glycolipids and their endogenous protein ligands, and to determine how the targeting of Gb3-positive cells by VT affects immune responses and the pathogenesis of VT producing E. coli infection. Specific aims are to: 1) Identify and define apoptosis pathways which require Gb3 by comparing such pathways in Gb3+ and Gb3- Burkitt's lymphoma cell lines. 2) Determine differential gene expression in Gb3+ and Gb3- Burkitt's lymphoma cells prior to and following treatment with inducers of apoptosis by performing microarray analysis, RT-PCR and northern analysis. 3) Identify and model potential VT-like Gb3-binding sites on proteins involved in apoptosis pathways which require Gb3.

由大肠杆菌产生的Verotoxins（VT，也称为滋贺毒素）。大肠杆菌血清型0157：H7和其它血清型被认为是溶血性尿毒综合征、出血性结肠炎和血小板减少性紫癜的病原体。VT的受体是神经酰胺三己糖（Gb 3或CD 77）和可能的其它含有Gal α 1 -4 Gal残基的鞘糖脂。Gb 3在B淋巴细胞发育的生发中心阶段表达。由于它们的表型相似性，Daudi细胞和其他Burkitt淋巴瘤衍生的细胞系用作GC B淋巴细胞的体外模型。Gb 3结合VT B亚基在其氨基酸序列中模拟干扰素-α受体的IFNAR-1亚基、B细胞蛋白CD 19和MHC II类蛋白。迄今为止的实验证据表明，Gb 3和Gb 3结合蛋白是伯基特淋巴瘤中许多信号转导途径的必要组分， GC B淋巴细胞。这些包括Gb 3/IFNAR-1在IFN-α诱导的生长抑制和粘附中的作用，Gb 3/CD 19在粘附中的相互作用和Gb 3/VT B亚基在诱导细胞凋亡中的相互作用。然而，关于哪些信号转导途径需要Gb 3，或者Gb 3在导致观察到的反应的途径中的确切作用，可获得的数据相对较少。我们的初步研究表明，Gb 3可能在Gb 3阳性B细胞的凋亡途径中发挥重要作用。我们建议使用Daudi细胞系（其表达高水平的Gb 3）和Daudi衍生的Gb 3缺陷VT 500细胞系进一步研究Gb 3在与细胞凋亡相关的信号转导中的作用。本研究的长期目标是确定Gb 3和其他含Gal α 1-4 Gal糖脂及其内源性蛋白配体的细胞功能，并确定VT靶向Gb 3阳性细胞如何影响免疫应答和VT产生E.大肠杆菌感染。具体目标是：1）通过比较Gb 3+和Gb 3- Burkitt淋巴瘤细胞系中需要Gb 3的细胞凋亡途径来鉴定和定义这些途径。2)通过进行微阵列分析、RT-PCR和北方分析，确定在用凋亡诱导剂处理之前和之后在Gb 3+和Gb 3- Burkitt淋巴瘤细胞中的差异基因表达。3)识别和模拟潜在的VT样Gb 3结合位点的蛋白质参与细胞凋亡途径，需要Gb 3。