The platelet receptor CLEC-2 is the only known endogenous ligand for the transmembrane receptor podoplanin, which is expressed on lymphatic endothelial cells (LEC) as well as a number of other cell types. Both CLEC-2 and podoplanin are required for normal lymphangiogenesis as mouse embryos lacking either protein develop a phenotype in which blood is detected in the lymphatic vessels. This thesis examines the role of the podoplanin-CLEC-2 interaction in the migratory and tube-forming capabilities of LEC. Addition of platelets or antibody-mediated podoplanin crosslinking both inhibited migration of LEC in transfilter migration assays in the presence, but not absence, of vascular endothelial growth factor (VEGF)-C. Similarly, platelets and podoplanin crosslinking reduced stability of LEC networks formed in co-cultures with fibroblasts. We also found that siRNA-mediated knockdown of podoplanin negated the pro-migratory effects of VEGF-C and VEGF-A. Furthermore, we obtained evidence that podoplanin signalling may involve RhoA and Rho-kinase, and that the effect of podoplanin might be linked to its phosphorylation by protein kinase A downstream of VEGF receptor signalling. These data suggest that the interaction of podoplanin and CLEC-2 prevents connection between blood and lymphatic vessels through reductions in LEC migration and stability of cell-cell interactions.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:655822 |
| Date | January 2015 |
| Creators | Langan, Stacey Anne |
| Publisher | University of Birmingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://etheses.bham.ac.uk//id/eprint/6037/ |
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