- To understand the regulation of the apolipoprotein (apo) AI-CIII-AIV gene cluster and its impact on high density lipoprotein (HDL) metabolism, cholesterol transport from peripheral tissues and atherogenesis.
- To develop mice and rabbits transgenic for unmodified and modified forms of the human cluster.
- To develop knock-out mice in which the coding frames of individual members of the cluster have been interrupted with minimal nucleotide variations.
Coronary heart disease is the major cause of mortality in the European Union. It is caused by atherosclerosis, in which there is focal deposition of cholesterol in the artery wall. Atherogenesis is influenced by plasma lipoproteins. Elevated plasma concentrations of low density lipoproteins (LDLs) accelerate the process. In contrast, atherogenesis is inversely related to the high density lipoprotein (HDL) concentration. This may reflect the role which the HDLs play in the transport of cholesterol from tissues (reverse cholesterol transport, RCT). Two of the major apolipoproteins (apos) of HDLS though to be important for RCT are apos AI and AIV, the genes which are located with the apo CIII gene in a cluster in the human chromosome 11. Most work on this cluster has focused on its individual members. However, there is good evidence that regulatory elements of each member are dispersed throughout the cluster. This project will for the first time analyse the function and regulation of the entire cluster. This will be achieved by expressing the human cluster in normal mice, hyperlipidaemic apo E knock-out mice, New Zealand White rabbits and hyperlipidaemic Watanabe rabbits. Clusters will be used that have been modified in vitro by the introduction of stop codons in the coding regions of two of the three genes, under which conditions all of the regulatory elements of the cluster will be retained, though only one gene (apo AI, apo CIII or apo AIV) will be expressed. In addition knock-out mice will be produced to better understand the functional organisation of the cluster. As members of the mouse cluster have been studied by others using only knock-outs with gross variations in the sequence, in this study the coding frames of members of the cluster will be interrupted by introducing small nucleotide variations. The different animal models will be compared with respect to lipoproteins, RCT and atherogenesis. The results will provide new insights into the pathogenesis of the disease. The feasibility of generating mice and rabbits transgenic for the unmodified human cluster has already been established.
Funding SchemeCSC - Cost-sharing contracts