Carbohydrate-carbohydrate interaction in cell biology

描述（由申请人提供）：碳水化合物-碳水化合物相互作用（CCI）作为细胞粘附基础的概念最初是在(i)我们对小鼠畸胎癌F9细胞自聚集机制的研究中提出的，该机制模拟着床前胚胎的压实；（ii） Max Burger和他的团队对海洋海绵细胞的物种特异性自聚集的研究。在过去的十年中，越来越多的结构被发现参与了同型或异型CCI，通过两个界面细胞表面的鞘糖脂（GSLs）簇发生。CCI已通过表面等离子体共振（SPR）光谱和原子力显微镜的先进技术得到了很好的阐述，其结合亲和力与碳水化合物-蛋白质相互作用（CPI）和蛋白质-蛋白质相互作用（PPI）的结合亲和力相同。CCI具有CPI或PPI所没有的独特特性。

DESCRIPTION (provided by applicant): The concept of carbohydrate-to-carbohydrate interaction (CCI) as a basis of cell adhesion was originally developed during (i) our studies on mechanism of autoaggregation of mouse teratocarcinoma F9 cells, which mimics compaction of pre-implantation embryo; and (ii) studies by Max Burger and his group on species-specific autoaggregation of marine sponge cells. During the past decade, an increasing variety of structures have been found to be involved in either homotypic or heterotypic CCI, occurring through clusters of glycosphingolipids (GSLs) at the surfaces of two interfacing cells. CCI has been well elaborated by advanced technology in surface plasmon resonance (SPR) spectroscopy and atomic force microscopy, and its binding affinity is in the same range as that of carbohydrate-to-protein interaction (CPI) and protein-to-protein interaction (PPI). CCI has unique features not found in CPI or PPI. The specific aims of the proposed studies are: 1. Explore new cell adhesion systems based on new types of CCI detected using previously untested GSLs, and PE-conjugated N-linked or O-linked oligosaccharide probes from glycoproteins: (a) CCI based on previously-untested GSL structures; (b) CCI based on N-linked or O-linked oligosaccharides, conjugated to PE, assembled as "glycosyl SAM" or "glycochip"; (c) cell adhesion system based on the newly-found CCI. 2. Elucidate and provide evidence for involvement of CCI as initial step in physiologically or pathobiologically relevant cell adhesion systems in which CCI is suggested to occur, (a) Further studies on Lex-based CCI and cadherin-based PPI in mouse teratocarcinoma F9 cell autoaggregation. (b) Other cell adhesion systems: (i) Lex-based cell-to-cell adhesion of contact-inhibited corneal epithelial cells; (ii) Gb4-dependent CCI in autoaggregation of human teratocarcinoma cells; (iii) Ley-to-H interaction mediating adhesion of human cancer cells to endothelial cells; (iv) Mechanism of melanoma cell adhesion to mouse endothelial cells, based on GM3-to-LacCer interaction. Cell adhesion through CCI observed in Project 1 or 2 will be confirmed by (i) ruling out possible involvement of carbohydrate-binding protein; (ii) application of RNAi approach; (iii) a new SPR/ "digital window" procedure.