The role of the Angiopoietins in vascular morphogenesis

摘要: The Angiopoietin/Tie system acts as a vascular specific ligand/receptor to control endothelial cell survival and maturation. Angiopoietin family includes four ligands (Angiopoietin-1, Angiopoietin-2 Angiopoietin-3/4) two corresponding tyrosine kinase receptors (Tie1 Tie2). Ang-1 Ang-2 are of Tie2 binding the receptor with similar affinity. activation promotes vessel assembly maturation by mediating signals for cells regulating recruitment mural cells. in paracrine agonistic manner inducing phosphorylation subsequent stabilization. In contrast, is produced an autocrine antagonist Ang-1-mediated activation. thereby primes endothelium exogenous cytokines induces destabilization at higher concentrations. strongly expressed vasculature many tumors it has been suggested that may act synergistically other such growth factor promote tumor-associated angiogenesis tumor progression. better mechanistic understanding Ang/Tie gradually paving way toward rationale exploitation this signaling therapeutic target neoplastic non-neoplastic diseases.