Substratum-Endothelial Cell Interactions in Basal and Cytokine Conditions

Endothelial cells (ECs) sense and adapt to their environment, allowing them to shift between a range of functional phenotypes. When connected in a monolayer they create the endothelium, a barrier and a platform from which ECs can individually respond to flow, and circulating cells and factors apically, cell density circumferentially, and substratum composition, stiffness, and texture basolaterally. Plasticity allows ECs to promote vascular homeostasis, and to interact with and modulate the immune system. Changes in endothelial state enable immune cells to migrate into the tissue to repair tissue damage and fight infection. However, the ECs also modulate the function of immune cells through the expression of adhesion molecules, chemokines, major histocompatibility complex (MHC), and an array of co-stimulatory and inhibitor molecules. These interactions allow ECs to act as antigen presenting cells (APCs) and influence the outcome of immune recognition. Thus, the study of ECs elucidates how microenvironment, vascular cell biology, and immune response are not only connected but interdependent. The response of ECs to different substratums is compared to the response by fibroblasts and epithelial cells.