endothelial cell chemotaxis

Definition

Target type: biologicalprocess

The directed movement of an endothelial cell guided by a specific chemical concentration gradient. Movement may be towards a higher concentration (positive chemotaxis) or towards a lower concentration (negative chemotaxis). [CL:0000115, GOC:BHF]

Endothelial cell chemotaxis is a crucial process in angiogenesis, the formation of new blood vessels. It involves the directed migration of endothelial cells towards a chemoattractant gradient, a concentration gradient of a chemical signal. Here's a detailed breakdown of the biological process:

1. **Chemoattractant Production:** Various factors can stimulate the production of chemoattractants, including:
* **Hypoxia:** Low oxygen levels in tissues trigger the release of factors like vascular endothelial growth factor (VEGF) and angiopoietin-1.
* **Inflammation:** Inflammatory mediators like TNF-α and IL-1β can also induce the production of chemoattractants.
* **Wound Healing:** Growth factors like PDGF and TGF-β are released during wound healing, attracting endothelial cells to the injured site.

2. **Chemoattractant Reception:** Endothelial cells possess specific receptors on their surface that bind to chemoattractants. These receptors are typically G protein-coupled receptors (GPCRs), such as VEGFR2, which binds to VEGF.

3. **Signal Transduction:** Upon binding to the receptor, the chemoattractant activates a signaling cascade within the endothelial cell. This cascade involves various intracellular messengers, such as:
* **Phosphoinositide 3-kinase (PI3K):** Activates downstream signaling pathways involved in cell survival and migration.
* **Ras:** Activates the MAPK pathway, which regulates gene expression and cell proliferation.
* **Calcium:** Increases intracellular calcium levels, triggering cytoskeletal rearrangements.

4. **Cytoskeletal Rearrangements:** The activated signaling pathways lead to the reorganization of the cytoskeleton, primarily actin filaments. This rearrangement involves the formation of filopodia, finger-like projections that extend towards the chemoattractant source.

5. **Cell Polarization:** The chemoattractant gradient induces polarization of the endothelial cell. The leading edge, facing the chemoattractant source, becomes enriched with receptors, signaling molecules, and adhesion molecules. The trailing edge, facing away from the chemoattractant, develops a retraction fiber.

6. **Adhesion and Migration:** The leading edge of the endothelial cell attaches to the extracellular matrix via integrins. Integrins are transmembrane receptors that connect the cytoskeleton to the extracellular matrix, providing traction for cell movement. As the cell migrates, the trailing edge detaches from the matrix and retracts.

7. **Proliferation and Tube Formation:** Once endothelial cells reach the target area, they proliferate and assemble into tube-like structures, forming new blood vessels. This process is regulated by growth factors and other signaling molecules involved in angiogenesis.

8. **Maturation and Remodeling:** Newly formed blood vessels undergo further maturation and remodeling to ensure proper function and integration into the existing vasculature. This involves recruitment of pericytes and smooth muscle cells, which provide structural support and regulate blood flow.'
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Proteins (4)

Compounds (13)