ZEB1 Mediated Coronary Artery Disease Risk in Vascular Smooth Muscle - PROJECT SUMMARY Coronary artery disease (CAD) is the leading cause of death worldwide, but therapeutic options beyond lipid lowering strategies remain lacking for due to the critical knowledge gap linking genetic risk factors to disease mechanisms. Smooth muscle cells (SMCs) play a critical role in atherosclerosis development. These cells undergo a phenotypic transition process, where they dedifferentiate and migrate out of the blood vessel media and contribute to the fibrous cap. Furthermore, SMCs have been identified as the primary source of genetic susceptibility to CAD. Dr. Daniel Li’s (PI) preliminary data prioritizing transcription factors involved in phenotypic transition using probabilistic cell fate mapping has identified the ZEB transcription factor family (ZEB1 and ZEB2) as key genes driving this process. ZEBs regulate cell proliferation and plasticity, while human genetics has associated both genes with CAD risk. The genetic risk signal near ZEB2 can be explained by its role as an epigenetic regulator of SMC fate. However, the cellular mechanism(s) by which ZEB1 influences disease risk are unknown. ZEB factors share conserved DNA binding domains but have low homology in protein interaction domains, allowing the recruitment of diverse epigenetic regulators. Furthermore, they have reciprocal cellular transcriptional profiles in atherosclerosis-relevant cell types. The primary objective of this proposal is to characterize and establish the causal role of ZEB1 in atherosclerosis development. The central hypothesis is that ZEB1 acts as a counter-regulatory factor to ZEB2 via epigenetic mechanisms to maintain a differentiated smooth muscle state in the setting of vascular wall stress. Aim 1 will use a translational Zeb1 knockout mouse model to determine the transcriptional, epigenetic, and plaque phenotype of SMC lineage cells. Aim 2 will use functional genomics and proteomics to determine how ZEB factors differentially regulate SMC transcriptional processes via epigenetic mechanisms. The results of this study will elucidate the underlying mechanisms by which two novel but potentially counter-regulatory CAD genes drive the phenotypic transition of SMCs. In parallel, Dr. Li will complete a comprehensive training plan to 1) advance his background in bioinformatic tools for genetics and genomics, 2) develop expertise in the use and applications of proteomics, 3) build upon scientific and communication skills, and 4) further develop his scientific writing and grantsmanship skills and transition to academic research independence. This research proposal will be guided by Dr. Quertermous, a world leader in cardiovascular genetics, and an advisory committee consisting of world-renowned experts in computational genomic methods, proteomics, cardiovascular epidemiology, and vascular biology. Through this project, Dr. Li will develop the skillset to become an independent investigator dedicated to deciphering the genetic risks in atherosclerosis and translating these findings towards clinical practice.
