Neuron-derived Neurotrophic Factor Functions as a Novel Modulator That Enhances Endothelial Cell Function and Revascularization Processes

Background: Tissue ischemia stimulates production of secreted factors that regulate angiogenesis. Results: Neuron-derived neurotrophic factor (NDNF) is up-regulated in endothelial cells in ischemic limbs of mice. NDNF stimulates endothelial cell function and promotes ischemia-induced revascularization through NOS-dependent mechanisms. Conclusion: NDNF functions as a novel modulator that stimulates revascularization processes. Significance: NDNF represents a novel therapeutic target for ischemic vascular diseases. Strategies to stimulate revascularization are valuable for cardiovascular diseases. Here we identify neuron-derived neurotrophic factor (NDNF)/epidermacan as a secreted molecule that is up-regulated in endothelial cells in ischemic limbs of mice. NDNF was secreted from cultured human endothelial cells, and its secretion was stimulated by hypoxia. NDNF promoted endothelial cell network formation and survival in vitro through activation of Akt/endothelial NOS (eNOS) signaling involving integrin v3. Conversely, siRNA-mediated knockdown of NDNF in endothelial cells led to reduction of cellular responses and basal Akt signaling. Intramuscular overexpression of NDNF led to enhanced blood flow recovery and capillary density in ischemic limbs of mice, which was accompanied by enhanced phosphorylation of Akt and eNOS. The stimulatory actions of NDNF on perfusion recovery in ischemic muscles of mice were abolished by eNOS deficiency or NOS inhibition. Furthermore, siRNA-mediated reduction of NDNF in muscles of mice resulted in reduction of perfusion recovery and phosphorylation of Akt and eNOS in response to ischemia. Our data indicate that NDNF acts as an endogenous modulator that promotes endothelial cell function and ischemia-induced revascularization through eNOS-dependent mechanisms. Thus, NDNF can represent a therapeutic target for the manipulation of ischemic vascular disorders.