Vcam1

VCAM-1, or vascular cell adhesion molecule 1, also known as CD106, is a member of the immunoglobulin superfamily of cell adhesion molecules. It is a type I transmembrane glycoprotein expressed primarily on vascular endothelial cells.

Expression of VCAM-1 is inducible; basal levels are low but increase in response to inflammatory cytokines such as tumor necrosis factor alpha (TNF-α) and interleukin-1 (IL-1). Other stimuli including lipopolysaccharide and oxidative stress can also upregulate VCAM-1.

Structure and ligands: The extracellular portion of VCAM-1 contains multiple immunoglobulin-like domains and mediates adhesion through binding to leukocyte integrins, chiefly the α4β1 integrin (VLA-4) and, to a lesser extent, α4β7. The molecule is anchored in the cell membrane with a cytoplasmic tail; proteolytic shedding can release a soluble form, sVCAM-1, into circulation.

Function: VCAM-1 promotes firm adhesion of leukocytes to the endothelium and facilitates transmigration into tissues during inflammation. It participates in immune surveillance, tissue repair, and broader inflammatory responses, and is part of the endothelium’s response to vascular injury.

Clinical relevance: Increased VCAM-1 expression and elevated circulating sVCAM-1 have been observed in conditions such as atherosclerosis, rheumatoid arthritis, inflammatory bowel disease, sepsis, and transplant rejection. VCAM-1 serves as a marker of endothelial activation and remains a focus of research into therapies that aim to limit leukocyte recruitment.