This thesis provides novel insights in the molecular mechanism of action of antagonists for the chemokine receptor CCR2. CCR2 belongs to the protein family of G protein-coupled receptors (GPCRs).... Show moreThis thesis provides novel insights in the molecular mechanism of action of antagonists for the chemokine receptor CCR2. CCR2 belongs to the protein family of G protein-coupled receptors (GPCRs). It is involved in several inflammatory diseases and therefore many small molecule antagonists targeting this receptor have been developed over the years. Unfortunately all clinical candidates tested so far appeared to lack efficacy in man, which stresses the need for a better understanding of their mechanism of action. This thesis revealed three separate binding pockets throughout the transmembrane receptor domain via which CCR2 can be pharmacologically modulated. Different routes towards insurmountable antagonism of CCR2 were described, either via noncompetitive or via long residence time antagonists. These results may allow a more rational design of future antagonists, and are equally important to understand the outcomes of studies with existing CCR2 antagonists. In concert with the currently expanding insight in the structure and signalling capacities of GPCRs, the data presented in this thesis allow to better fine-tune the pharmacological modulation of the chemokine receptor CCR2, and GPCRs in general Show less
Cells express a large array of membrane receptors on their surface that function as a communication channel between the extra- and intracellular environment of the cell. Ligands for these receptors... Show moreCells express a large array of membrane receptors on their surface that function as a communication channel between the extra- and intracellular environment of the cell. Ligands for these receptors span a wide range of biomolecules, from proteins to carbohydrates to small molecules. Some receptors are continuously recycling between the membrane and the inside of a cell, whereas others are in a steady-state at the membrane and need ligand binding for their activation and subsequent internalization. Synthetic molecules that bind to these membrane receptors can be used to either modulate their function, or to target a reporter group (i.e. a fluorescent dye) and/or a bio-active compound (drug, protein) to cells that express this receptor, ensuring delivery to a specific cell-type. The research described in this Thesis combines synthetic and biochemical methodologies to create ligands that interact selectively with membrane receptors of the GPCR and lectin-binding families. Attachment of synthetic probes, proteins or cytostatic molecules to these ligands by a variety of chemical and enzymatic methods ensured their uptake exclusively into cells that expressed the receptor of interest. Visualization of this process was enabled by the incorporation of a fluorescent dye into the final constructs. Show less
