Structural Glycobiology of Leukocyte Adhesion/Migration in the Lymphatics studied by NMR spectroscopy

透明质酸(HA)是一种在间质基质中高度丰富的糖胺聚糖，通过与白细胞HA受体CD44相互作用，在白细胞的黏附/迁移中发挥重要作用。在免疫监视和初级T细胞反应的过程中，淋巴系统被白细胞利用，从组织转移到引流的淋巴结。然而，淋巴系统的血管不表达CD44，但另一种HA受体LYVE-1表达。重组Lyve-1在体外与HA和可溶性CD44形成稳定的复合物，通过HA介导表达CD44的细胞与淋巴管内皮细胞的基底外侧和管腔表面的黏附，在体内支持白细胞向淋巴结的转运。在肿瘤细胞表面也发现了高浓度的HA，伴随着CD44表达的增加，先前的研究发现肿瘤细胞表面的HA含量与其形成淋巴结转移的能力密切相关。虽然CD44-HA复合体的三维结构已经通过X射线和核磁共振确定，但LYVE-1还没有高分辨率的三维分子结构。我们的目标是用核磁共振波谱和计算方法揭示LYVE-1识别配体的结构细节。基于配体的核磁共振实验(饱和转移差核磁共振、转移NOE、水LOGSY)将提供结构和亲和力的细节，对接计算将产生能量有利的三维分子模型，核磁共振观测数据的计算预测将验证三维结构。LYVE-1的结合特征将与CD44的结合特征进行比较，以扩大我们在结构方面对HA分子识别的不同性质的理解，这被认为是白细胞滚动的关键。选定的候选者将在设备齐全的实验室工作，拥有最先进的HPC集群和强大的核磁共振设备(主要是800和500 MHz光谱仪)，在高度刺激的科学环境中工作，包括与UEA和诺里奇研究园区(NRP)的国际知名科学家合作。

Hyaluronan (HA), a glycosaminoglycan highly abundant at the interstitial matrix, plays a fundamental role in leukocyte adhesion/migration, by interacting with the leukocyte HA receptor CD44. During processes of immune surveillance and primary T-cell responses, the lymphatic system is exploited by leukocytes for trafficking from the tissues to the draining lymph nodes. However, the vessels of lymphatic system do not express CD44, but another HA receptor termed LYVE-1. Recombinant LYVE-1 form stable complexes with HA and soluble CD44 in vitro, supporting a role in trafficking of leukocytes to the lymph nodes in vivo, by HA-mediated adhesion of CD44-expressing cells to the basolateral and luminal surfaces of the lymphatic endothelium. HA is also found in high concentrations on the surfaces of tumour cells, along with an increased expression of CD44, and previous studies have found the HA surface content of tumour cells closely related to their ability to form node metastases. Although the 3D structure of the CD44-HA complex has been determined by X-ray and NMR, for LYVE-1 there is no high-resolution 3D molecular structure available.We aim to reveal structural details on the recognition of ligands by LYVE-1 using NMR spectroscopy and computational methods. Ligand-based NMR experiments (saturation transfer difference NMR, transferred NOE, WaterLOGSY) will afford structural and affinity details, docking calculations will generate energetically favourable 3D molecular models of the complexes, and computational prediction of NMR observables will validate the 3D structures. The binding features of LYVE-1 will be compared to those of CD44, to extend our understanding in structural terms of the distinct properties of both receptors for the molecular recognition of HA, proposed to be key for leukocyte rolling.The selected candidate will work in well-equipped laboratories, with access to state of the art HPC Cluster and powerful NMR equipment (mainly 800 and 500 MHz spectrometers), in a highly stimulating scientific environment that includes collaboration with internationally distinguished scientists at UEA and the Norwich Research Park (NRP).