Summary The vascular system constantly remodels in response to tissue growth or changes in metabolism to efficiently deliver nutrients and oxygen to tissues. Remodeling encompasses sprouting angiogenesis, arteriogenesis and expanding vessel diameters. Failure of these mechanisms contributes greatly to coronary artery disease, peripheral artery disease and cerebral vascular dysfunction. While many genes and signaling proteins in these processes have been identified, our incomplete understanding of regulatory networks impedes identification of therapeutic targets and development of new treatments for these conditions. Vascular remodeling is regulated principally by VEGF secreted by ischemic cells of the target tissues, and fluid shear stress (FSS) from blood flow that act on vascular endothelial cells (ECs). Our recent work has revealed novel aspects of FSS- dependent remodeling and interactions between FSS and VEGF that determine these processes. But we know little about how these pathways interact to determine tissue-level outcomes. The Kholodenko lab has developed a powerful new method called cell State Transition Assessment and Regulation (cSTAR) for exploiting `omics' data to develop pathway models that can accurately encompass cell regulation, predict outcomes, and identify therapeutic targets. Our three labs will work closely together to acquire quantitative data on interactions within vascular remodeling regulatory networks and develop a quantitative model of vascular remodeling that will be tested in vitro and in vivo. Aim 1 will address the roles of VEGF and FSS in EC fate decisions during angiogenesis and arteriogenesis. Here, we will perturb candidate mediators of FSS and VEGF signaling and measure effects on signaling and gene expression pathways. cSTAR will then identify and precisely quantify causal connections in the regulatory network that guides EC phenotypic transitions to allow purposeful manipulation of EC states and fate decisions, which will then be tested experimentally in vitro. Aim 2 will utilize a similar strategy to address the effects of low, physiological, high and oscillatory FSS that determine artery diameter and disease susceptibility. We will first characterize the effects of FSS profiles on pathway activation, then carry out a perturbation study to determine effects of inhibiting pathways on EC signaling and gene expression. cSTAR will again develop a causal computational model and generate predictions that for testing in vitro. Aim 3 will then test predictions in vivo in mice, deleting candidate genes and observing the impact on vascular remodeling. Together, these studies will develop a novel experimental- computational approach to elucidate in unprecedented depth the regulatory networks that govern vascular remodeling and develop insights into these biological processes that identify novel therapeutic targets for improving vascular insufficiency in coronary, peripheral and cerebral artery disease.