Angiopoietin
Angiopoietin is part of a family of vascular growth factors that play a role in embryonic and postnatal angiogenesis.
Angiopoietin signaling most directly corresponds with angiogenesis, the process by which new arteries and veins form from preexisting blood vessels.
Angiogenesis proceeds through sprouting, endothelial cell migration, proliferation, and vessel destabilization and stabilization.
[2] Angiopoietin cytokines are involved with controlling microvascular permeability, vasodilation, and vasoconstriction by signaling smooth muscle cells surrounding vessels.
The two receptor pathways are named as a result of their role in mediating cell signals by inducing the phosphorylation of specific tyrosines.
This in turn initiates the binding and activation of downstream intracellular enzymes, a process known as cell signaling.
[8] Although which specific TIE receptors mediate signals downstream of angiogenesis stimulation is highly contested, it is clear that TIE-2 is capable of activation as a result of binding angiopoietins.
These Tyrosine kinase receptors are typically expressed on vascular endothelial cells and specific macrophages for immune responses.
This growth factor is also a glycoprotein and functions as an agonist for the tyrosine receptor found in endothelial cells.
These connections are a key determinant of vascular permeability and relieve peri-endothelial cell contact, which is also a major factor in vessel stability and maturity.
[17] Deregulation of angiopoietin and the tyrosine kinase pathway is common in blood-related diseases such as diabetes, malaria,[18] sepsis, and pulmonary hypertension.
The combination of fever and high levels of angiopoietin-2 are correlated with a greater prospect of the development of septic shock.
[2] Angiopoietin-2 is produced and stored in Weibel-Palade bodies in endothelial cells and acts as a TEK tyrosine kinase antagonist.
[9] Serum levels of angiopoietin-2 expression are associated with the growth of multiple myeloma,[19] angiogenesis, and overall survival in oral squamous cell carcinoma.
This is relevant for clinical use relative to cancer treatments because the inhibition of angiogenesis can aid in suppressing tumor proliferation.
