Overall Despite the development of increasingly effective therapies to reduce elevated levels of atherogenic lipoproteins, cardiovascular disease (CVD) complications are projected to rise worldwide due in part to the increasing incidence of obesity and insulin resistance. An emergent question is the extent to which non-alcoholic fatty liver disease (NAFLD), which is a spectrum ranging from fatty liver to non-alcoholic steatohepatitis (NASH) to cirrhosis, contributes to CVD risk. Among patients with NAFLD, the leading cause of death is CVD, estimated to account for 31% of total mortality. The development of NAFLD and cardiovascular disease is influenced by combinations of genetic and environmental factors, some of which are disease-specific and others that affect both disease processes. The overall hypotheses of our PPG are that liver fat and fibrosis predict CVD risk and that interventions targeting Liver X receptors (LXRs) in macrophages, the farnesyl X receptor (FXR) in the gut, and oxidation specific epitopes (OSEs) in the liver and artery wall will reveal common mechanisms that contribute to the clinical association between NASH and CVD. Importantly, each of these interventions make use of representative small molecules or antibodies that have the potential to be advanced for clinical trials. Identifying mechanisms by which known and unknown risk factors promote both NASH and CVD would be of great significance, especially if targeting one or more of these mechanisms would produce beneficial effects on both diseases. To achieve this goal, we propose a PPG consisting of four highly inter-related projects and three cores. Project 1, led by Dr. Christopher Glass, will test the hypothesis that selective activation of LXRs in macrophages and Kupffer cells with desmosterol mimetics will result in reductions of atherosclerosis and NASH without causing steatosis or hypertriglyceridemia. Project 2, led by Dr. Ronald Evans, will investigate the hypothesis that selective activation of FXR in the gut or liver will result in reductions in atherosclerosis and NASH. Project 3, led by Dr. Joseph Witztum, will test the hypothesis that antibody-mediated reductions in OSEs will coordinately reduce both atherosclerosis and NASH. Project 4, led by Dr. Rohit Loomba, will investigate the relationships of liver fat content and fibrosis with cardiovascular risk in human subjects and enable translational extension of mechanistic findings made in Projects 1, 2 and 3. A Phenotyping Core will enable Projects 1, 2 and 3 to quantitatively evaluate extent of atherosclerosis and NASH in mouse models, and enable all projects to obtain targeted lipidomic profiles and cytokine levels from relevant samples. A Genomics and Bioinformatics Core will support the application of massively parallel sequencing-based assays, such as RNA Seq, by Projects 1, 2 and 3 and provide a shared resource for bioinformatics and statistical analysis. An Administrative Core will support the overall administrative and scientific needs of the PPG.
Overall The proposed studies will identify mechanisms that promote both non-alcoholic steatohepatitis and atherosclerosis, providing a rational basis for development of therapeutic approaches that would have a beneficial impact on both diseases.