Brain-derived neurotrophic factor promotes angiogenesis via oxidative stress in human vascular endothelial cells: Implication for atherogenesis?

Abstract

Aim: Brain-derived neurotrophic factor (BDNF), a major type of neurotrophins, promotes synaptic plasticity and neuronal cell survival, which contribute to the maintenance of structure and function of neuronal cells. Recent studies also indicate a possible involvement of BDNF in the atherogenesis. However, the detailed mechanisms for this remain to be fully clarified. We hypothesized that BDNF may at least partly play a role in the atherosclerotic plaque development through the promotion of angiogenesis. To gain mechanistic insights, we examined whether BDNF causes angiogenesis and underlying mechanisms with focusing on reactive oxygen species (ROS) and related intracellular signals in human cultured vascular endothelial cells (ECs).

Methods and results: In vascular ECs, BDNF increased ROS generation as measured fluorometrically using 2’ 7’-dichlorofluorescein diacetate as well as NADPH oxidase (NOX) activity as determined by a chemiluminescent measurement. BDNF-increased ROS generation and NOX activity were inhibited by K252a, an inhibitor of tropomyosin-related kinase B (TrkB) receptor. BDNF caused phosphorylation of p47 phox, a regulatory component of NOX, which was inhibited by K252a as determined by Western blotting. In matrigel, BDNF caused angiogenic tube formation of ECs, which was inhibited by K252a or gp91ds-tat, a specific inhibitor of NOX. BDNF induced phosphorylation of Akt but not ERK in ECs, which was inhibited by K252a or gp91ds-tat. It was further confirmed that small interfering RNA (siRNA) against TrkB inhibited BDNF-induced ROS generation and tube formation.

Conclusion: The present results for the first time showed that BDNF promotes angiogenesis through NOX-derived ROS generation via the activation of p47 phox in a TrkB receptor-dependent manner.