Investigating the principles of physiological and pathological vascular remodeling via 4D imaging of live mouse skin - PROJECT SUMMARY The cutaneous vasculature is a crucial yet understudied component of the skin, responsible for essential functions such as tissue oxygenation, exchange of nutrients and soluble factors, and temperature control. While we have a significant understanding of vascular abnormalities present in various skin pathologies, we lack an understanding of both physiological remodeling and homeostatic mechanisms sustaining lifelong function. Specifically, we lack the resolution of the coordinated cellular behaviors that drive developmental vascular remodeling, as well as those that underlie vascular regeneration in the face of injury, particularly in the context of hemodynamic status. I hypothesize that network-wide coordination of EC behaviors in relation to hemodynamic changes regulates developmental and regenerative remodeling programs of the skin vasculature. To test this hypothesis, I have established an intravital imaging technique that allows for the longitudinal tracking and manipulation of the endothelial cells (ECs) that constitute the lining of all blood vessels in the skin of a live mouse. In Aim 1, I will investigate the neonatal vessel remodeling program and underlying EC behaviors that orchestrate the establishment of skin vascular network architecture and blood flow efficiency. Following establishment of adult vascular homeostasis, I will probe the cellular mechanisms that regulate the maintenance of adult vessel integrity via a targeted laser ablation approach, modeling the discrete membrane damage inflicted upon the endothelium due to shear and contractile forces. My preliminary data shows that EC migration within existing vessel structures is a critical EC behavior that underlies network-wide vessel regression during neonatal remodeling, as well as the reparative response of adult ECs to local damage. In Aim 2, I will transition my studies towards the understanding of the skin vasculature in the context of pathological states. Firstly, I will investigate the wound vascularization mechanisms of neonatal versus adult skin, and delineate the differential remodeling properties that enable the enhanced wound revascularization in neonatal skin that we have observed in preliminary experiments. Second, I will determine how coordination of flow-dependent EC rearrangement impacts the ability of adult wounds to revascularize via a genetic mutant model that uncouples the ability of ECs to polarize with respect to blood flow direction. To achieve these aims, I will use an integrated approach of cutting-edge imaging technology, transcriptomics, and genetic mouse models. This research is significant because we expect to uncover global cellular and molecular mechanisms that coordinate vascular development, homeostasis, and injury repair. My findings will likely drive innovation in related fields, given the ubiquity and crucial roles of the vasculature in all organs.
