Investigating Complex Glycans on Biological Surfaces

描述（由申请人提供）：复合物聚糖普遍分布在细胞间表面的界面，作为各种微生物病原体的受体，在决定病原体的宿主细胞和组织向性方面起关键作用。尽管它们在宿主-病原体相互作用中很重要，但将聚糖-蛋白相互作用的生化和生物物理特异性与这些相互作用调节的生物学功能联系起来一直是一个挑战。这些挑战来自于难以在不同组织的上皮表面等生理环境中表征多糖受体的精细结构粒度。因此，有必要在组织，细胞和分子水平上架起聚糖结构表征的桥梁。在这些水平上解码生理聚糖受体的多样性不仅有助于从理解发病机制的角度确定聚糖受体靶点，而且有助于制定对抗病原体感染的治疗策略。我们已经开始通过开发一个多方面的框架来解码聚糖-蛋白质相互作用的结构-功能关系来解决上述问题。利用组织凝集素染色和基于质谱的代表性细胞类型聚糖结构分析的结合，我们已经迈出了一步，在组织和细胞水平上连接聚糖的表征。植物凝集素传统上被用来研究聚糖结构基序（由凝集素识别）在细胞和组织表面的生理背景下的分布。然而，基于凝集素染色的聚糖受体的多样性已经以抽象的方式或充其量以末端聚糖键如a2-3或a2-6连接的唾液酸来表征。植物凝集素与聚糖结合特性的丰富结构和生化信息为开发利用这些凝集素探索超越末端键的生理聚糖的更精细结构细节的新策略提供了巨大的潜力。基于这些信息，凝集素可以被设计成靶向病原体和宿主聚糖受体之间的相互作用。在我们之前的努力的基础上，我们寻求开发利用植物凝集素的策略，以新的方式获得生理聚糖受体的更详细的结构特征，并开发这些凝集素来靶向病原体-宿主聚糖受体的相互作用。

DESCRIPTION (provided by applicant): Complex glycans, which are ubiquitously distributed at the interface of intercellular surfaces, act as receptors for various microbial pathogens and play a key role in determining the pathogen's hostcellular and tissue tropism. Despite their importance in host-pathogen interaction, it has been challenging to bridge the biochemical and biophysical specificity of glycan-protein interactions with the biological functions modulated by these interactions. These challenges arise from the difficulties in characterizing the fine structural granularity of glycan receptors in their physiological context such as epithelial surface of different tissues. Therefore there is a need to bridge the structural characterization of glycans at the tissue, cellular and molecular levels. Decoding the diversity of the physiological glycan receptors at these levels would not only facilitate the identification of glycan receptor targets from the standpoint of understanding pathogenesis but would also facilitate development of therapeutic strategies to counter pathogen infection. We have begun to address the above issues by developing a multifaceted framework to decode the structure-function relationship of glycan-protein interactions. Using a combination of lectin staining of tissues and mass spectrometry based structural profiling of glycans isolated from representative cell types we have taken a step towards bridging the characterization of glycans at the tissue and cellular level. Plant lectins have traditionally been used to investigate distribution of glycan structural motifs (recognized by the lectins) in the physiological context of cell and tissue surfaces. However, the diversity of glycan receptors based on lectin staining have been characterized in a abstract fashion or at best in terms of terminal glycan linkages such as a2-3 or a2-6 linked sialic acids. The abundant structural and biochemical information on glycan-binding properties of plant lectins offers tremendous potential to develop new strategies for using these lectins to probe into finer structural details of physiological glycans going beyond terminal linkages. Based on this information, lectins can be engineered to target interactions between pathogens and their host glycan receptors. Building on our previous efforts in this proposal we seek to develop strategies that utilize plant lectins in new ways to obtain more detailed structural characterization of physiological glycan receptors as well as develop these lectins to target pathogen-host glycan receptor interactions. PUBLIC HEALTH RELEVANCE: Complex glycans decorate biological surfaces specifically the interface of intercellular surfaces where they play a critical role in mediating cell - cell interactions such as host cell - pathogen interactions. There are challenges in bridging the physiological glycan receptor binding of pathogens with the biology of their pathogenesis and host adaptation. These challenges arise from the limitations in characterizing the fine structural diversity of glycan receptors in the appropriate physiological context such as specific cell and tissue surfaces. In this proposal we seek to address this issue by exploiting the untapped potential of plant lectins both to obtain a detailed mapping of the nuances in the structural features of the glycan receptors in physiological surfaces such as human upper respiratory epithelia and to develop these lectins as tools to competitively target these receptors.