Hydrogen sulfide (H2S) promotes angiogenesis

Anastasia Pyriochou1, Gabor Olah2, Csaba Szabo3, Andreas Papapetropoulos1
1University of Patras, Department of Pharmacy, Laboratory of Molecular Pharmacology, Patras, Achaia, Greece, 2University of Medicine and Dentistry of New Jersey, Department of Surgery, Newark, New Jersey, United States, 3Ikaria Inc., Seattle, Washington, United States

Angiogenesis is essential during physiological responses such as exercise training and the menstrual cycle, as well as in disease states (cancer, diabetic retinopathy, rheumatoid arthritis). Hydrogen sulfide (H2S) is a recently described signalling molecule with important actions in the cardiovascular system; however, its role on angiogenesis has not been investigated in detail. To this end, we utilized an H2S-donor and determined its effects on angiogenesis in vivo, as well as on angiogenesis-related properties of endothelial cells (EC). Treatment of chicken chorioallantoic membranes (CAM), which is a widely used model for in vivo angiogenesis, with the H2S-donor (0.24 pmol/egg to 240 pmol/egg) increased vascular length in a dose-dependent manner, reaching a maximum of 48.4±11.6 % at 240 pmol/egg. In vitro, incubation of human umbilical vein endothelial cells (HUVEC) with the H2S-donor (6 μM to 600 μM) promoted cell growth, with a maximal proliferation of 202.3±38.3 % observed at 600 μM. Moreover, treatment of HUVEC with the H2S-donor (60 μM) increased EC migration by 4-fold and stimulated their assembly into tube-like networks by 1.5-fold. To identify the molecular mechanisms implicated in H2S-stimulated angiogenesis-related properties of EC, we used inhibitors of kinases known to be involved in neovascularization. Inhibition of MEK by PD98059 (10 μμ) and p38 by SB203580 (3 μM), attenuated H2S-induced cell migration. However, inhibition of the PI3-kinase by LY294002 (5 μM), did not affect the H2S-enhanced motility of EC. Overall, we provide evidence that H2S induces neo-vessel formation in vivo and promotes the angiogenic phenotype of endothelial cells in vitro, via the activation of MAPK family members.