leukocyte adhesion to vascular endothelial cell

Definition

Target type: biologicalprocess

The attachment of a leukocyte to vascular endothelial cell via adhesion molecules. [GOC:add, GOC:bc, GOC:BHF, GOC:BHF_miRNA, PMID:23897866]

Leukocyte adhesion to vascular endothelial cells is a critical step in the immune response, enabling circulating white blood cells to migrate from the bloodstream into tissues where they are needed to combat infection, injury, or inflammation. This complex process involves a series of molecular interactions between leukocytes and the endothelial lining of blood vessels, orchestrated by a tightly regulated cascade of events.

1. **Rolling:** The initial interaction between leukocytes and the endothelium is a rolling phase, mediated by selectin molecules. Selectins are adhesion molecules expressed on both leukocytes and endothelial cells. L-selectin on leukocytes binds to GlyCAM-1 and CD34 on endothelial cells, while E-selectin and P-selectin on activated endothelial cells bind to sialyl Lewis X (sLex) and other ligands on leukocytes. This interaction results in the leukocytes rolling along the endothelium, slowing down their movement and allowing them to sample the local environment.

2. **Activation:** As the leukocytes roll along the endothelium, they encounter chemokines, small signaling molecules released by activated endothelial cells and other cells in the surrounding tissue. These chemokines activate integrins on the leukocytes, transforming them from a low-affinity to a high-affinity state.

3. **Firm Adhesion:** The activated integrins on leukocytes bind tightly to their ligands, including ICAM-1, ICAM-2, and VCAM-1, which are expressed on endothelial cells. This firm adhesion arrests the leukocytes and allows them to crawl along the endothelial surface.

4. **Transmigration:** Once firmly adhered to the endothelial cells, leukocytes begin to transmigrate through the vascular wall into the underlying tissue. This process is facilitated by PECAM-1 (CD31), an adhesion molecule expressed on both leukocytes and endothelial cells, and by matrix metalloproteinases (MMPs) that degrade the extracellular matrix surrounding the blood vessels.

Leukocyte adhesion to endothelial cells is a highly regulated process, ensuring that leukocytes are recruited to sites of inflammation or infection in a timely and efficient manner. This process is tightly controlled by a variety of factors, including chemokines, cytokines, and other signaling molecules. Dysregulation of leukocyte adhesion can contribute to various pathological conditions, including inflammatory diseases, autoimmune disorders, and cancer metastasis.

The molecular interactions involved in leukocyte adhesion are highly complex and diverse. Understanding the details of this process is essential for developing effective therapies for a wide range of diseases.'
"

Proteins (1)

Compounds (19)