In this project a novel approach of effect-directed drug design in used to fill this gap. This approach is based on a non-exclusive model of agonist and antagonist interaction with receptor; its combination with quantitative structure-activity analysis allows prediction of the type of ligand action (agonist, antagonist or partial agonist). In this project we will express a series of the recombinant P2Y receptors in cell lines, in which the activation of these receptors is coupled to intracellular Ca2+- mobilization. The dose-response relationships of receptor activation can thus be determinated by means of fluorescence measurements to detect Ca2+mobilization. This assay system enables rapid screening of ligands and will be used for systematic studies of ligand-binding specificity of these receptor subtypes, analyzed proceeding from the modified receptor concept. Following the results of these studies new types of purinoceptor ligands will be developed, including nucleoside-coupled peptides. Screening of the activity of these ligands will be made by using synthetic combinatorial libraries, based on randomization of either the peptide or nucleotide parts of these compounds.
A regulatory function of nucleotide (ATP, UMP,ADP, etc), interacting as extracellular transmitter through specific nucleotide receptors ("P2 purinoceptors") has been discovered recently and was finally established by the DNA-cloning of some of these receptors. It is becoming evident that purinergic receptors may present a novel amplification mechanism, strengthening the cellular responses in situations of crisis. This is exemplified by the platelet aggregation reaction where release of nucleotide (ADP) from one platelet activates and recruits hundred of other platelets, thus rapidly initiating blood clotting. It is obvious that such amplification is augmented in pathological conditions and the appropriate regulatory system is a potential target for drug, action, directed towards mechanisms which are primarily pathologic. Numerous in vitro and some in vivo studies have indicated that ATP is a co-transmitter in adrenergic neurones, where blocking of purinergic receptors attenuates sympathetic adrenergic responses. Thus, cardiovascular therapy directed against adrenergic receptors should be either potentiated or inhibited by P2 purinoceptor antagonists. For all of these reasons, therefore, that class of drug could be a new perspective for therapeutics for such diseases as hypertension, myocardial ischemia, and thrombosis. Developments in this area, are however, hampered by the lack of effective and subtype-specific antagonists of P2 receptors.
Funding SchemeCSC - Cost-sharing contracts
NW3 2PF London