Crosstalk between adenosine receptors and CYP450-derived oxylipins in the modulation of cardiovascular, including coronary reactive hyperemic response.

Adenosine is a ubiquitous endogenous nucleoside or autacoid that affects the cardiovascular system through the activation of four G-protein coupled receptors: adenosine A1 receptor (A1AR), adenosine A2A receptor (A2AAR), adenosine A2B receptor (A2BAR), and adenosine A3 receptor (A3AR). With the rapid generation of this nucleoside from cellular metabolism and the widespread distribution of its four G-protein coupled receptors in almost all organs and tissues of the body, this autacoid induces multiple physiological as well as pathological effects, not only regulating the cardiovascular system but also the central nervous system, peripheral vascular system, and immune system. Mounting evidence shows the role of CYP450-enzymes in cardiovascular physiology and pathology, and the genetic polymorphisms in CYP450s can increase susceptibility to cardiovascular diseases (CVDs). One of the most important physiological roles of CYP450-epoxygenases (CYP450-2C & CYP2J2) is the metabolism of arachidonic acid (AA) and linoleic acid (LA) into epoxyeicosatrienoic acids (EETs) and epoxyoctadecaenoic acid (EpOMEs) which generally involve in vasodilation. Like an increase in coronary reactive hyperemia (CRH), an increase in anti-inflammation, and cardioprotective effects. Moreover, the genetic polymorphisms in CYP450-epoxygenases will change the beneficial cardiovascular effects of metabolites or oxylipins into detrimental effects. The soluble epoxide hydrolase (sEH) is another crucial enzyme ubiquitously expressed in all living organisms and almost all organs and tissues. However, in contrast to CYP450-epoxygenases, sEH converts EETs into dihydroxyeicosatrienoic acid (DHETs), EpOMEs into dihydroxyoctadecaenoic acid (DiHOMEs), and others and reverses the beneficial effects of epoxy-fatty acids leading to vasoconstriction, reducing CRH, increase in pro-inflammation, increase in pro-thrombotic and become less cardioprotective. Therefore, polymorphisms in the sEH gene (Ephx2) cause the enzyme to become overactive, making it more vulnerable to CVDs, including hypertension. Besides the sEH, ω-hydroxylases (CYP450-4A11 & CYP450-4F2) derived metabolites from AA, ω terminal-hydroxyeicosatetraenoic acids (19-, 20-HETE), lipoxygenase-derived mid-chain hydroxyeicosatetraenoic acids (5-, 11-, 12-, 15-HETEs), and the cyclooxygenase-derived prostanoids (prostaglandins: PGD2, PGF2α; thromboxane: Txs, oxylipins) are involved in vasoconstriction, hypertension, reduction in CRH, pro-inflammation and cardiac toxicity. Interestingly, the interactions of adenosine receptors (A2AAR, A1AR) with CYP450-epoxygenases, ω-hydroxylases, sEH, and their derived metabolites or oxygenated polyunsaturated fatty acids (PUFAs or oxylipins) is shown in the regulation of the cardiovascular functions. In addition, much evidence demonstrates polymorphisms in CYP450-epoxygenases, ω-hydroxylases, and sEH genes (Ephx2) and adenosine receptor genes (ADORA1 & ADORA2) in the human population with the susceptibility to CVDs, including hypertension. CVDs are the number one cause of death globally, coronary artery disease (CAD) was the leading cause of death in the US in 2019, and hypertension is one of the most potent causes of CVDs. This review summarizes the articles related to the crosstalk between adenosine receptors and CYP450-derived oxylipins in vascular, including the CRH response in regular salt-diet fed and high salt-diet fed mice with the correlation of heart perfusate/plasma oxylipins. By using A2AAR-/-, A1AR-/-, eNOS-/-, sEH-/- or Ephx2-/-, vascular sEH-overexpressed (Tie2-sEH Tr), vascular CYP2J2-overexpressed (Tie2-CYP2J2 Tr), and wild-type (WT) mice. This review article also summarizes the role of pro-and anti-inflammatory oxylipins in cardiovascular function/dysfunction in mice and humans. Therefore, more studies are needed better to understand the crosstalk between the adenosine receptors and eicosanoids to develop diagnostic and therapeutic tools by using plasma oxylipins profiles in CVDs, including hypertensive cases in the future.

Adenosine A2A receptor and vascular response: role of soluble epoxide hydrolase, adenosine A1 receptor and angiotensin-II.

Previously, we have reported that the coronary reactive hyperemic response was reduced in adenosine A2A receptor-null (A2AAR-/-) mice, and it was reversed by the soluble epoxide hydrolase (sEH) inhibitor. However, it is unknown in aortic vascular response, therefore, we hypothesized that A2AAR-gene deletion in mice (A2AAR-/-) affects adenosine-induced vascular response by increase in sEH and adenosine A1 receptor (A1AR) activities. A2AAR-/- mice showed an increase in sEH, AI AR and CYP450-4A protein expression but decrease in CYP450-2C compared to C57Bl/6 mice. NECA (adenosine-analog) and CCPA (adenosine A1 receptor-agonist)-induced dose-dependent vascular response was tested with t-AUCB (sEH-inhibitor) and angiotensin-II (Ang-II) in A2AAR-/- vs. C57Bl/6 mice. In A2AAR-/-, NECA and CCPA-induced increase in dose-dependent vasoconstriction compared to C57Bl/6 mice. However, NECA and CCPA-induced dose-dependent vascular contraction in A2AAR-/- was reduced by t-AUCB with NECA. Similarly, dose-dependent vascular contraction in A2AAR-/- was reduced by t-AUCB with CCPA. In addition, Ang-II enhanced NECA and CCPA-induced dose-dependent vascular contraction in A2AAR-/- with NECA. Similarly, the dose-dependent vascular contraction in A2AAR-/- was also enhanced by Ang-II with CCPA. Further, t-AUCB reduced Ang-II-enhanced NECA and CCPA-induced dose-dependent vascular contraction in A2AAR-/- mice. Our data suggest that the dose-dependent vascular contraction in A2AAR-/- mice depends on increase in sEH, A1AR and CYP4A protein expression.

Cyp2j5-Gene Deletion Affects on Acetylcholine and Adenosine-Induced Relaxation in Mice: Role of Angiotensin-II and CYP-Epoxygenase Inhibitor.

Previously, we showed vascular endothelial overexpression of human-CYP2J2 enhances coronary reactive hyperemia in Tie2-CYP2J2 Tr mice, and eNOS-/- mice had overexpression of CYP2J-epoxygenase with adenosine A2A receptor-induced enhance relaxation, but we did not see the response in CYP2J-epoxygenase knockout mice. Therefore, we hypothesized that Cyp2j5-gene deletion affects acetylcholine- and 5'-N-ethylcarboxamidoadenosine (NECA) (adenosine)-induced relaxation and their response is partially inhibited by angiotensin-II (Ang-II) in mice. Acetylcholine (Ach)-induced response was tested with N-(methylsulfonyl)-2-(2-propynyloxy)-benzenehexanamide (MS-PPOH, CYP-epoxygenase inhibitor; 10-5M) and Ang-II (10-6M). In Cyp2j5-/- mice, ACh-induced relaxation was different from C57Bl/6 mice, at 10-5 M (76.1 ± 3.3 vs. 58.3 ± 5.2, P < 0.05). However, ACh-induced relaxation was not blocked by MS-PPOH in Cyp2j5-/- : 58.5 ± 5.0%, P > 0.05, but blocked in C57Bl/6: 52.3 ± 7.5%, P < 0.05, and Ang-II reduces ACh-induced relaxation in both Cyp2j5-/- and C57Bl/6 mice (38.8 ± 3.9% and 45.9 ± 7.8, P <0.05). In addition, NECA-induced response was tested with Ang-II. In Cyp2j5-/- mice, NECA-induced response was not different from C57Bl/6 mice at 10-5M (23.1 ± 2.1 vs. 21.1 ± 3.8, P > 0.05). However, NECA-induced response was reduced by Ang-II in both Cyp2j5-/- and C57Bl/6 mice (-10.8 ± 2.3% and 3.2 ± 2.7, P < 0.05). Data suggest that ACh-induced relaxation in Cyp2j5-/- mice depends on nitric oxide (NO) but not CYP-epoxygenases, and the NECA-induced different response in male vs. female Cyp2j5-/- mice when Ang-II treated.