Phosphodiesterase 2 mediates redox-sensitive endothelial cell proliferation and angiogenesis by thrombin via Rac1 and NADPH oxidase 2.
Cyclic nucleotide phosphodiesterases (PDEs) control the levels of the second messengers cAMP and cGMP in many cell types including endothelial cells. Although PDE2 has the unique property to be activated by cGMP but to hydrolyze cAMP, its role in endothelial function is only poorly understood. Reactive oxygen species (ROS) have been recognized as signaling molecules controlling many endothelial functions. We thus investigated whether PDE2 would link to ROS generation and proliferative responses in human umbilical vein endothelial cells in response to thrombin. Thrombin stimulated the GTPase Rac1, known to activate NADPH oxidases, and enhanced ROS formation, whereas PDE2 inhibition or depletion by short hairpin (sh)RNA prevented these responses. Similar observations were made with 8-Br-cGMP or atrial natriuretic peptide. In agreement, thrombin elevated cGMP but decreased cAMP levels, whereas db-cAMP or forskolin diminished Rac1 activity and ROS production. Subsequently, PDE2 overexpression activated Rac1, increased ROS generation, and enhanced proliferation and in vitro capillary formation. These responses were not observed in the presence of inactive Rac1 or shRNA against the NADPH oxidase subunit NOX2. Inhibition or depletion of PDE2 also prevented thrombin-induced proliferation and capillary formation. Importantly, downregulation of PDE2 by lentiviral shRNA or PDE2 inhibition prevented vessel sprouting from mouse aortic explants and in vivo angiogenesis in a mouse model, respectively. In summary, PDE2 promotes activation of NADPH oxidase-dependent ROS production and subsequent endothelial proliferation and angiogenesis. Targeting PDE2 may provide a new therapeutic approach in diseases associated with endothelial dysfunction, oxidative stress, vascular proliferation, and angiogenesis.
Diebold
Isabel
I
Experimental Pediatric Cardiology, Department of Pediatric Cardiology and Congenital Heart Disease, German Heart Center Munich at the TU Munich, Lazarettstr. 36, D-80636 Munich, Germany.
Djordjevic
Talija
T
Petry
Andreas
A
Hatzelmann
Armin
A
Tenor
Hermann
H
Hess
John
J
Görlach
Agnes
A
D000818:Animals; D001011:Aorta / Q000166:cytology / Q000378:metabolism; D049109:Cell Proliferation; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000378:metabolism; D054678:Cyclic Nucleotide Phosphodiesterases, Type 2 / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000378:metabolism*; D018919:Neovascularization, Physiologic / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013917:Thrombin / Q000378:metabolism*; D014471:Umbilical Veins / Q000166:cytology / Q000378:metabolism; D054462:p21-Activated Kinases / Q000378:metabolism; D020830:rac1 GTP-Binding Protein / Q000378:metabolism*
D008562:Membrane Glycoproteins; D017382:Reactive Oxygen Species; C056558:CYBB protein, human; C488842:Cybb protein, mouse; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; C515903:PAK1 protein, human; C515905:Pak1 protein, mouse; D054462:p21-Activated Kinases; D054678:Cyclic Nucleotide Phosphodiesterases, Type 2; D013917:Thrombin; D020830:rac1 GTP-Binding Protein; D006152:Cyclic GMP