Arachidonic Acid Epoxygenase Metabolites Stimulate Endothelial Cell Growth and Angiogenesis via Mitogen-Activated Protein Kinase and Phosphatidylinositol 3-Kinase/Akt Signaling Pathways

Abstract

Cytochrome P450 arachidonic acid (AA) epoxygenase metabolites, the epoxyeicosatrienoic acids (EETs), dilate arteries via hyperpolarization of smooth muscle cells and also have nonvasodilatory effects within the vasculature. The present study investigated the angiogenic effects of endogenous and exogenous EETs and the relevant signaling mechanisms involved. Bovine aortic endothelial cells (BAECs) were incubated with synthetic EETs or infected with recombinant adeno-associated viruses (rAAVs) containing CYP2C11-NADPH-cytochrome P450 oxidoreductase (CYPOR), CYP2J2, or CYP102 F87V mutant to increase endogenous levels of EETs. The following endpoints were measured: BAEC proliferation, migration, capillary formation, and in vivo angiogenesis. The potential involvement of various signaling pathways was explored using selective inhibitors. The results showed that transfection with either rAAV-CYP2C11-CYPOR, rAAV-CYP2J2, or rAAV-CYP102 F87V, or incubation with EETs promoted BAEC proliferation, increased migration of BAECs as assessed by Transwell analysis and wound healing assays, and enhanced capillary tubule formation as determined by chicken embryo chorioallantoic membrane assays and tube formation tests on matrigel. The effects of EETs on proliferation, migration, and capillary tubule formation were attenuated by inhibitors of mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3 (PI3)-kinase/ Akt pathways and partially attenuated by an endothelial nitricoxide synthase (eNOS) inhibitor but not by a protein kinase C inhibitor. In a rat ischemic hind limb model, rAAV-mediated AA epoxygenase transfection induced angiogenesis. We conclude that AA epoxygenase metabolites can promote angiogenesis, which may provide protection to ischemic tissues. The results also suggest that the angiogenic effects of EETs involve the MAPK and PI3-kinase/Akt signaling pathways, and to some extent, the eNOS pathway.Arachidonic acid (AA) is esterified to cell membrane glycerophospholipids and liberated by phospholipase A 2 in response to various stimuli. AA can be activated by three different enzyme pathways: the cyclooxygenase, the lipoxygenase, and the cytochrome P450 (P450) monooxygenase

Müller glia cells regulate Notch signaling and retinal angiogenesis via the generation of 19,20-dihydroxydocosapentaenoic acid

“…1 A), and although the EETs reported to induce angiogenesis in the chick chorioallantoic membrane (Michaelis et al, 2003) and the vascularization of Matrigel plugs implanted into wild-type mice Webler et al, 2008). Moreover, the overexpression of the human CYP2C11 and 2J2 enzymes in the ischemic rat hindlimb model was found to increase muscle capillary density (Wang et al, 2005). However, such studies could not address the importance of endogenously generated CYP metabolites and were difficult to back up in knockout models, as there are major differences in CYP epoxygenase isoform expression between species.…”

Activation of the ERK signaling pathway is involved in CD151-induced angiogenic effects on the formation of CD151-integrin complexes

“…Previous studies have shown that activation of ERK is generally associated with cell proliferation, angiogenesis and tumor metastasis [17,25] . p38 is usually activated by inflammatory cytokines and leads to cell apoptosis [16,18] .…”

Role of epoxyeicosatrienoic acids in protecting the myocardium following ischemia/reperfusion injury

“…This effect is diminished upon hydrolysis of EETs to DHETs by sEH [22]. Other studies have shown that EETs display antiinflammatory, thrombolytic and angiogenic properties within the vasculature [23][24][25]. In endothelial cells, EETs activate mitogen activated protein kinase (MAPK) and phosphatidylinositol-3 kinase (PI3K)-Akt signaling pathways [25], increase intracellular cAMP levels [24], upregulate expression of nitric oxide synthase [26] and protect against hypoxia-reoxygenation injury [27].…”