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

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).