Measuring the functional heterogeneity of endothelial cells in engineered vasculature

University Of Delaware, Newark DE

Investigators

Abstract

Project Summary Measuring the functional heterogeneity of endothelial cells in engineered vasculature Clinical translation of tissue engineered products requires the development of vascularized constructs, as most cells are metabolically dependent on oxygen and nutrient delivery from blood vessels. Current approaches for establishing engineered blood vessels rely on the ability of endothelial cells to self-assemble into vessel networks in biomaterial scaffolds. In vivo, endothelial cells are highly heterogeneous, exhibiting varying ability to form hierarchal vessel structures (i.e., from highly branched, small diameter capillary vessels to larger diameter arteries/veins). State-of-the-art methods for engineering vasculature overlook this cellular heterogeneity when combining tissue-derived endothelial cells with scaffolds, resulting in the formation of defective and disorganized vessel structures that do not efficiently deliver oxygen and nutrients to cells. Thus, there is a critical need to measure endothelial cell heterogeneity for successful engineering of functional vasculature. Motivated by our previous work demonstrating that single-cell heterogeneities in mesenchymal stromal cells can be quantified by specific integrin expression, we propose to measure endothelial cell heterogeneity based on the expression of integrins and cadherins with various biosensing approaches. Our central hypothesis is that measuring the expression of endothelial cell surface integrin and cadherin receptors will identify quantifiable heterogeneities in endothelial cells, which will yield novel approaches to sort heterogeneous endothelial cell subpopulations and genetically modify the cells’ integrin and cadherin expression to better control blood vessel formation. We will evaluate cell heterogeneities as the ability of the cells to form blood vessels of varying diameter, length, and branching index. Our preliminary study correlates the magnitude of β1-integrin and VE-cadherin expression by primary endothelial cells with vascularization capacity in collagen gels. We will further quantify the expression of other integrins and cadherins and characterize the ability of endothelial cells to form various blood vessel geometries in collagen gels (Aim 1). We will then engineer blood vessels with different geometries using endothelial cells sorted based on integrin and cadherin expression (Aim 2). Finally, we will genetically modify the expression of integrins and cadherins on endothelial cells both in vitro and in vivo to regulate their vascularization capacity (Aim 3). Successful completion of this project will yield innovative approaches to measure, understand, exploit, and manipulate heterogeneities in endothelial cell capacity to self- assemble into vasculature. Ultimately, these findings will provide a powerful, new approach to precisely control blood vessel formation and will enhance the clinical success of engineered blood vessel therapies. Furthermore, this proposal and the opportunities afforded by the COBRE will develop synergistic collaborations to measure and sense cellular heterogeneities in vascular tissue engineered constructs.