E-Selectin, officially known as Endothelial Leukocyte Adhesion Molecule-1 (ELAM-1) or CD62E, is a member of the Selectin family of cell surface glycoproteins with a molecular weight ranging from 107 to 115 kDa. This cell adhesion molecule plays a pivotal role in inflammation and neovascularization, particularly in wound healing and ischemic areas.
Upon tissue injury, the release of cytokines and chemokines, such as stromal cell-derived factor 1α (SDF-1α), triggers the local expression of membrane-bound E-Selectin on endothelial cells. Concurrently, it induces the expression of systemic reciprocal E-Selectin ligands on endothelial progenitor cells (EPCs) within the bone marrow, mediated by the C-X-C motif chemokine receptor 4 (CXCR4).
E-Selectin is transiently expressed on vascular endothelial cells in response to cytokines like IL-1 beta and TNF-alpha, peaking at 4 hours post-activation and decaying by 24 hours. This cell surface glycoprotein is integral to immune cell adhesion, specifically by interacting with SELPLG/PSGL1 on blood neutrophils, which facilitates their adhesion to cytokine-activated endothelium. E-Selectin may also contribute to capillary morphogenesis.
During inflammation, E-Selectin mediates the attachment of flowing leukocytes to the blood vessel wall by binding to E-Selectin ligands present on leukocytes. These initial interactions are dynamic, allowing leukocytes to roll along the vascular endothelium in the direction of blood flow. Subsequently, stronger interactions involving ICAM-1 and VCAM-1 lead to the extravasation of white blood cells through the blood vessel wall and into the extracellular matrix of surrounding tissues.