Cumulative evidences suggest that nerve growth factor (NGF) promotes angiogenic effects such as proliferation and migration of endothelial cells (ECs) from different vascular beds, induces capillary sprouting in chorioallantoic membrane and improves in vivo vascularization in a hind-limb ischemic model. In the present study, we sought to investigate the signaling properties of NGF in a microcapillary ECs model compared to those of a neuronal model. NGF-induced phosphorylation of signaling molecules Erk1/2, Akt and PLCγ were measured using Western blotting and compared between mouse NGF (mNGF) and snake venom NGF analogues. NGFs-induced signaling was TrkA mediated as evident by inhibition with the TrkA antagonist K252a. NGF and its analogues-induced signaling in ECs were characterized by a transient effect in contrast to a prolonged stimulation in neuronal cells. The potency of mouse, cobra and viper NGFs to induce Erk1/2 phosphorylation in ECs was higher than in neurons. In ECs, mNGF exhibited the highest efficacy of stimulation of Erk1/2 phosphorylation, followed by viper and cobra NGFs. The efficacy of stimulation of Erk1/2 phosphorylation measured with neurons was opposite from that in ECs. NGF-induced temporal signaling differences between ECs and neurons may explain the dual vascular and neurotrophic effects of this growth factor.
Bibliographical noteFunding Information:
This work was supported in part by a grant-in-aid form the Stein Family Foundation (PL and PIL); PL is affiliated and partially supported by the David R. Bloom Center for Pharmacy ; and the Dr. Adolf and Klara Brettler Center for Research in Molecular Pharmacology and Therapeutics at The Hebrew University of Jerusalem, Israel ; SL is supported by “Eshkol” fellowship from the Israeli Ministry of Science and Technology , and acknowledge the travel support from Boehringer Ingelhein Fonds. The authors would like to acknowledge Ms. Dana Stoler for technical assistance, Ms. Zehava Cohen for graphics design and the constructive remarks of the reviewers.