Project Summary This K08 mentored clinical scientist research career development award is a five-year program designed to facilitate Dr. Marios Arvanitis’ (PI) development into an independent physician-investigator in vascular genetics. Atherosclerotic cardiovascular disease (ASCVD) is a major public health burden that accounts for over 600,000 deaths in the United States each year. ASCVD is highly heritable and genome-wide association studies have discovered many candidate genomic loci that increase the risk of the disease in the population, thereby providing a window to novel therapies. However, most genomic risk loci for ASCVD remain unexplored in terms of how they lead to disease risk. Previously published work by the PI has focused on the mechanistic interpretation of genomic risk loci for cardiovascular disease, including the development of a novel Bayesian method, called CAFEH, to prioritize the target tissue and genes in genomic loci. Our preliminary analyses of the genetic underpinnings of ASCVD reveal that endothelial cells are enriched for ASCVD heritability, and we have used those methods to prioritize a chromosome 4 locus that is predicted to affect ASCVD risk via altering the expression of the RE-1 silencing transcription factor (REST) gene in endothelial cells. This K08 project will explore the regulatory mechanisms via which the REST locus and gene influence the development of atherosclerosis. Aim 1 will employ CRISPR-Cas9 editing in human stem cells which will then be differentiated into endothelial cells to identify the causal variants and the upstream transcription factors that mediate the association in the 4q12 coronary disease GWAS locus. Aim 2 will define distal genes and pathways affected by REST in the endothelium and investigate their cellular consequences, starting with evaluating the role of REST in endothelial to mesenchymal transition. Aim 3 will use a tamoxifen inducible endothelial specific Rest knock-out mouse model to evaluate the in vivo effects of Rest in the endothelium and atherosclerosis. The success of this project is guaranteed by the support of a multidisciplinary mentoring team including a vascular biologist (Dr. Charles Lowenstein), a computational biologist (Dr. Alexis Battle), and a functional genetics expert (Dr. Andrew McCallion), along with an advisory committee of experts in vascular biology, stem cell differentiation and atherosclerosis (Dr. Harry Dietz, Dr. Chulan Kwon and Dr. Thomas Quertermous). This award period will help the PI boost their genomics skills, acquire new wet lab skills and generate preliminary data to successfully compete for R01 funding in order to translate the genetic insights into novel mechanisms for ASCVD.

Project Narrative Atherosclerotic cardiovascular disease (ASCVD) is a challenging and highly prevalent human disease that has a major genetic component, but many of the identified genetic risk loci for the disease remain unexplored with unknown target genes or tissues in which they act. In my prior work I have used human genetic data from multiple individuals and discovered that one of those uncharacterized genetic loci affects a new gene in endothelial cells called REST. This proposal will use novel laboratory genetics methods that manipulate endothelial cells in the lab and a genetic mouse model of REST inactivation to understand how our DNA affects REST in endothelial cells and how REST can affect the walls of our arteries to cause ASCVD.