Interleukin-5 suppresses Vascular Endothelial Growth Factor-induced angiogenesis through STAT5 signaling.

Interleukin-5 (IL-5) is best known as key regulator in eosinophil-associated diseases such as asthma. While a connection to vascular changes in eosinophil-associated lung diseases is still elusive, recent evidence suggests that IL-5 may have an atheroprotective role. Here, we report an unexpected anti-angiogenic potential of IL-5 on vascular endothelial cells in vitro. IL-5 significantly inhibited fundamental functions of human lung microvascular endothelial cells (HMVEC-L) in vessel formation including VEGF-induced endothelial cell proliferation, migration and tube formation. Knockdown (KD) of STAT5 abolished the direct anti-angiogenic effect of IL-5 on VEGF-induced endothelial cell proliferation, migration and tube formation.