Cyclooxygenase-2 and adenylate cyclase/protein kinase A signaling pathway enhances angiogenesis through induction of vascular endothelial growth factor in rat sponge implants.
Angiogenesis is reportedly enhanced by prostaglandins (PGs). In the present experiment, we tested whether or not COX-2 and adenylate cyclase/protein kinase A (AC/PKA)-dependent VEGF induction enhanced angiogenesis in this model. Angiogenesis was enhanced by topical injection of human recombinant basic fibroblast growth factor (bFGF). The enhanced angiogenesis by bFGF was inhibited by indomethacin or selective COX-2 inhibitors, NS398, nimesulide, and JTE-522. Topical daily injections of 8-bromo-cAMP enhanced angiogenesis in a dose-dependent manner. Forskolin, an activator of AC, also facilitated angiogenesis in a dose-dependent manner, as did amrinone, an inhibitor of phosphodiesterase. VEGF induction was confirmed by the increased levels in the fluids in the sponge matrix after topical injection of 8-bromo-cAMP. Immunohistochemical investigation further revealed the VEGF-expressed cells in the sponge granulation tissues to be fibroblasts, and the intensity of positive reactions was enhanced by bFGF, 8-bromo-cAMP, forskolin, and amrinone. Angiogenesis was inhibited by indometacin or selective COX-2 inhibitors, NS-398, nimesulide, and JTE-522. In addition, angiogenesis without topical injections of the above compounds was also suppressed by SQ22,536, an inhibitor for AC. or H-89, an inhibitor for PKA, with concomitant reductions in VEGF levels. Daily topical injections of neutralizing antibody or anti-sense oligonucleotide against VEGF significantly suppressed angiogenesis. These results suggested that COX-2 and AC/PKA-dependent induction of VEGF certainly enhanced angiogenesis, and that pharmacological tools for controlling this signaling pathway may be able to facilitate the management of conditions involving angiogenesis.
Amano
Hideki
H
Department of Thoracic and Cardiovascular Surgery, Kitasato University School of Medicine, Kanagawa, Japan. hideki@med.kitasato-u.ac.jp
Haysahi
Izumi
I
Yoshida
Satoko
S
Yoshimura
Hirokuni
H
Majima
Masataka
M
D000262:Adenylyl Cyclases / Q000502:physiology*; D000818:Animals; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology*; D051546:Cyclooxygenase 2; D016228:Endothelial Growth Factors / Q000378:metabolism / Q000502:physiology*; D006097:Granulation Tissue / Q000098:blood supply* / Q000378:metabolism; D020007:Implants, Experimental; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism / Q000502:physiology*; D007527:Isoenzymes / Q000502:physiology*; D008222:Lymphokines / Q000378:metabolism / Q000502:physiology*; D018919:Neovascularization, Physiologic; D011140:Polyurethanes; D011451:Prostaglandin-Endoperoxide Synthases / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000502:physiology*; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D036341:Intercellular Signaling Peptides and Proteins; D007527:Isoenzymes; D008222:Lymphokines; D011140:Polyurethanes; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; C028279:polyurethane foam; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D017868:Cyclic AMP-Dependent Protein Kinases; D000262:Adenylyl Cyclases