Increased vascular 20-HETE is associated with hypertension and activation of the renin-angiotensin system (RAS) through induction of vascular angiotensin-converting enzyme (ACE) expression. Cyp4a12tg mice, whose Cyp4a12-20-HETE synthase expression is under the control of a tetracycline (doxycycline, DOX) promoter, were used to assess the contribution of ACE/RAS to microvascular remodeling in 20-HETE-dependent hypertension. Treatment of Cyp4a12tg mice with DOX increased systolic blood pressure (SBP; 136 ± 2 vs. 102 ± 1 mmHg; P < 0.05), and this increase was prevented by administration of 20-HEDGE, lisinopril, or losartan. DOX-induced hypertension was associated with microvascular dysfunction and remodeling of preglomerular microvessels, which was prevented by 20-HEDGE, a 20-HETE antagonist, yet only lessened, but not prevented, by lisinopril or losartan. In ACE 3/3 mice, which lack vascular endothelial ACE, administration of 5α-dihydrotestosterone (DHT), a known inducer of 20-HETE production, increased SBP; however, the increase was about 50% of that in wild-type (WT) mice (151 ± 1 vs. 126 ± 1 mmHg). Losartan and 20-HEDGE prevented the DHT-induced increase in SBP in WT and ACE 3/3 mice. DHT treatment increased 20-HETE production and microvascular remodeling in WT and ACE 3/3 mice; however, remodeling was attenuated in the ACE 3/3 mice as opposed to WT mice (15.83 ± 1.11 vs. 22.17 ± 0.92 μm; P < 0.05). 20-HEDGE prevented microvascular remodeling in WT and ACE 3/3 mice, while losartan had no effect on microvascular remodeling in ACE 3/3. Taken together, these results suggest that RAS contributes to 20-HETE-mediated microvascular remodeling in hypertension and that 20-HETE-driven microvascular remodeling independent of blood pressure elevation does not fully rely on ACE activity in the vascular endothelium.

20-HETE is a potent inducer of endothelial ACE in vitro and administration of lisinopril or losartan attenuates blood pressure in models of 20-HETE-dependent hypertension. The present study was undertaken to further define the relationship between 20-HETE and the renin-angiotensin system in hypertension using an angiotensinogen-deficient mouse (Agt+/-). Treatment of male AGT+/- with 5α-dihydrotestosterone (DHT) increased systolic BP from 102±2 to 125±3mmHg; in comparison, the same treatment raised BP in wild type (WT) from 110±2 to 138±2mmHg. DHT increased vascular 20-HETE levels in AGT+/- and WT from 1.5±0.7 and 2.1±0.6 to 13.0±2.0 and 15.8±4.0ng/mg, respectively. Concurrent treatment with the 20-HETE antagonist, 20-hydroxyeicosa-6(Z),15(Z)-dienoic acid (20-HEDE) prevented the increases in BP in both AGT+/- and WT mice. Administration of 20-HEDE at the peak of the DHT-induced BP increase (12 days) reduced BP to basal levels after 48h. Interestingly, basal levels of renal microvascular EETs were higher in AGT+/- compared to WT (55.2±9.7 vs 20.0±4.1ng/mg) and treatment of AGT+/- with DHT decreased the levels of EETs (28.4±5.1ng/mg). DHT-mediated changes in vascular EET level were not observed in WT mice. Vascular Cyp4a12 and ACE protein levels were increased in both AGT+/- and WT by 30-40% and decreased with concomitant administration of 20-HEDE. Lisinopril was as effective as 20-HEDE in preventing DHT-mediated increases in BP in both AGT+/- and WT mice. This study substantiates our previous findings that the RAS plays an important role in 20-HETE-mediated hypertension. It also proposes a novel interaction between 20-HETE and EETs.

20-HETE-mediated hypertension in rats and mice is associated with increased vascular ACE expression and Ang II levels. We examined the contribution of vascular ACE to blood pressure (BP) and vascular remodeling in 20-HETE-dependent hypertension. The ACE3/3 mice lack vascular endothelial ACE, exhibit attenuated renal ACE expression and display normal plasma ACE and Ang II levels. Administration of 5α-dihydrotestosterone (DHT) (100 mg; 21-day pellet), an inducer of 20-HETE production, increased systolic BP (SBP) by 50% in WT mice (148±4 vs 99±2 mmHg) and 26% in ACE 3/3 mice (125±1 vs 99±1 mmHg). Administration of losartan (10 mg/kg/day) or 20-HEDGE (20-HETE antagonist, 10mg/kg/day) at day 14 of DHT treatment reduced SBP in WT and ACE3/3 mice to levels of untreated mice. DHT increased ACE protein in WT by 2.3-fold in mesenteric and 2.6-fold in aortic arteries while ACE3/3 mice lacked vascular ACE expression which remained absent under DHT treatment. DHT increased preglomerular microvessel (PGMV) remodeling in WT and ACE3/3 mice; however, remodeling was attenuated in ACE3/3 mice (media thickness, 14.54±1.24 vs 9.80±0.56 μm; p<0.05) as opposed to WT mice (22.17±0.92 vs 9.68±0.76 μm; p<0.05). In Cyp4a12tg mice, in which the expression of the Cyp4a12-20-HETE synthase is under the control of the doxycycline (DOX) promoter, DOX (1 mg/ml drinking water) increased SBP (136±2 vs 102±1 mmHg; p<0.05). The increase in SBP was prevented by co-treatment with 20-HEDGE (103±3mmHg), lisinopril (100±3mmHg), or losartan (102±3mmHg). DOX treatment increased PGMV remodeling when compared to untreated Cyp4a12tg mice (media thickness, 16.1±0.9 vs. 8.2±0.5 μm, p<0.05). Co-treatment with 20-HEDGE (10 mg/kg/day) prevented DOX-induced PGMV remodeling (8.8±0.6 μm, p<0.05) while co-treatment with lisinopril or losartan attenuated but did not prevent PGMV remodeling (12.0±0.5 and 11.1±0.5 μm). DOX-treated Cyp4a12tg displayed increased ACE expression in PGMV which was negated by treatment with 20-HEDGE but unaffected by either losartan or lisinopril treatment. These results suggest that vascular endothelial ACE contributes, in part, to 20-HETE-mediated microvascular remodeling in hypertension and that 20-HETE have effects on microvascular remodeling independent of RAS.

20-Hydroxy-5, 8, 11, 14-eicosatetraenoic acid (20-HETE) is a cytochrome P450 (CYP)–derived omega-hydroxylation metabolite of arachidonic acid. 20-HETE has been shown to play a complex role in blood pressure regulation. In the kidney tubules, 20-HETE inhibits sodium reabsorption and promotes natriuresis, thus, contributing to antihypertensive mechanisms. In contrast, in the microvasculature, 20-HETE has been shown to play a pressor role by sensitizing smooth muscle cells to constrictor stimuli and increasing myogenic tone, and by acting on the endothelium to further promote endothelial dysfunction and endothelial activation. In addition, 20-HETE induces endothelial angiotensin-converting enzyme, thus, setting forth a potential feed forward prohypertensive mechanism by stimulating the renin–angiotensin–aldosterone system. With the advancement of gene sequencing technology, numerous polymorphisms in the regulatory coding and noncoding regions of 20-HETE–producing enzymes, CYP4A11 and CYP4F2, have been associated with hypertension. This in-depth review article discusses the biosynthesis and function of 20-HETE in the cardiovascular system, the pharmacological agents that affect 20-HETE action, and polymorphisms of CYP enzymes that produce 20-HETE and are associated with systemic hypertension in humans.

20-Hydroxy-5, 8, 11, 14-eicosatetraenoic acid (20-HETE) is a cytochrome P450 (CYP)-derived omega-hydroxylation metabolite of arachidonic acid. 20-HETE has been shown to play a complex role in blood pressure regulation. In the kidney tubules, 20-HETE inhibits sodium reabsorption and promotes natriuresis, thus, contributing to antihypertensive mechanisms. In contrast, in the microvasculature, 20-HETE has been shown to play a pressor role by sensitizing smooth muscle cells to constrictor stimuli and increasing myogenic tone, and by acting on the endothelium to further promote endothelial dysfunction and endothelial activation. In addition, 20-HETE induces endothelial angiotensin-converting enzyme, thus, setting forth a potential feed forward prohypertensive mechanism by stimulating the renin-angiotensin-aldosterone system. With the advancement of gene sequencing technology, numerous polymorphisms in the regulatory coding and noncoding regions of 20-HETE-producing enzymes, CYP4A11 and CYP4F2, have been associated with hypertension. This in-depth review article discusses the biosynthesis and function of 20-HETE in the cardiovascular system, the pharmacological agents that affect 20-HETE action, and polymorphisms of CYP enzymes that produce 20-HETE and are associated with systemic hypertension in humans.

Although the mechanism underlying the effect of androgen on BP and cardiovascular disease is not well understood, recent studies suggest that 20-hydroxy-5,8,11,14-eicosatetraenoic acid (20-HETE), a primary cytochrome P450 4 (Cyp4)-derived eicosanoid, may mediate androgen-induced hypertension. Here, treatment of normotensive mice with 5α-dihydrotestosterone increased BP and induced both Cyp4a12 expression and 20-HETE levels in preglomerular microvessels. Administration of a 20-HETE antagonist prevented and reversed the effects of dihydrotestosterone on BP. Cyp4a14(-/-) mice, which exhibit androgen-sensitive hypertension in the male mice, produced increased levels of vascular 20-HETE; furthermore, administration of a 20-HETE antagonist normalized BP. To examine whether androgen-independent increases in 20-HETE are sufficient to cause hypertension, we studied Cyp4a12-transgenic mice, which express the CYP4A12-20-HETE synthase under the control of a doxycycline-sensitive promoter. Administration of doxycycline increased BP by 40%, and administration of a 20-HETE antagonist prevented this increase. Levels of CYP4A12 and 20-HETE in preglomerular microvessels of doxycycline-treated transgenic mice approximately doubled, correlating with increased 20-HETE-dependent sensitivity to phenylephrine-mediated vasoconstriction and with decreased acetylcholine-mediated vasodilation in the renal microvasculature. We observed a similar contribution of 20-HETE to myogenic tone in the mesenteric microvasculature. Taken together, these results suggest that 20-HETE both mediates androgen-induced hypertension and can cause hypertension independent of androgen.

20-Hydroxyeicosatetraenoic acid (20-HETE) is a cytochrome P-450 (Cyp)-derived arachidonic acid metabolite that has been shown to increase smooth muscle contractions and proliferation, stimulate endothelial dysfunction and activation, and promote hypertension. We examined if 20-HETE contributes to microvascular remodeling in hypertension. In Sprague-Dawley rats, administration of the 20-HETE biosynthesis inhibitor HET0016 or the 20-HETE antagonist N-20-hydroxyeicosa-6(Z),15(Z)-dienoic acid (20-HEDE) prevented 5α-dihydrotestosterone (DHT)-induced increases in blood pressure as well as abrogated DHT-induced increases in the media-to-lumen ratio (M/L), media thickness, and collagen IV deposition in renal interlobar arteries. Reserpine prevented blood pressure elevation in DHT-treated rats but did not affect microvascular remodeling (M/L, media thickness, and collagen deposition); under these conditions, treatment with the 20-HETE antagonist attenuated microvascular remodeling, suggesting that 20-HETE contributes to DHT-induced vascular remodeling independent of blood pressure elevation. In Cyp4a14(-/-) mice, which display androgen-driven and 20-HETE-dependent hypertension, treatment with the 20-HETE antagonist abolished remodeling of renal resistance arteries measured as media thickness (24 ± 1 vs. 15 ± 1 μm) and M/L (0.29 ± 0.03 vs. 0.17 ± 0.01). Moreover, in Cyp4a12 transgenic mice in which the expression of Cyp4a12-20-HETE synthase is driven by a tetracycline-sensitive promoter, treatment with doxycycline resulted in blood pressure elevation (140 ± 4 vs. 92 ± 5 mmHg) and a significant increase in remodeling of renal resistance arteries (media thickness: 23 ± 1 vs. 16 ± 1 μm; M/L: 0.39 ± 0.04 vs. 0.23 ± 0.02); these increases were abrogated by cotreatment with 20-HEDE. This study demonstrated that 20-HETE is a key regulator of microvascular remodeling in hypertension; its effect is independent of blood pressure elevation and androgen levels.

20-Hydroxyeicosatetraenoic acid (20-HETE) is a microcirculatory cytochrome P450-derived eicosanoid shown to increase smooth muscle contractions and proliferation, stimulate endothelial dysfunction and activation, and promotes hypertension. We developed a mouse model (Cyp4a12tg) in which the expression of Cyp4a12, the sole 20-HETE synthase in mouse, is under the control of the doxycycline (DOX) promoter. Administration of DOX to Cyp4a12tg mice increased blood pressure (131±3 vs 100±2 mmHg, p<0.05), which was prevented by co-treatment with the 20-HETE antagonist, 20-HEDGE (96±3 mmHg, p<0.05). Media-to-lumen ratio and medial cross sectional area of renal microvessels from DOX-treated Cyp4a12tg mice significantly increased compared to untreated (M/L, 0.15±0.01 vs 0.07±0.01; mCSAx103 10.8±0.92 vs. 6.4±0.48 mm2); these increases were abolished by co-treatment with 20-HEDGE. Cardiac output and heart rate were unchanged, whereas %EF and %FS were reduced and LV volume and diameter at systole increased in DOX-treated Cyp4a12tg. Total peripheral resistance (TPR) was significantly increased in DOX-treated Cyp4a12tg mice (8.00±0.39 vs 6.77±0.36 mmHg/ml/min, p<0.05); co-treatment with 20-HEDGE decreased (p<0.0%) DOX-induced TPR in Cyp4a12tg mice (7.45±0.22 mmHg/ml/min). These results indicate that activation of Cyp4a12-20-HETE synthase causes hypertension, microvascular remodeling, and cardiac dysfunction. The results also suggest that 20-HETE promotes hypertension by increasing TPR. However, the mechanisms underlying Cyp4a12-20-HETE-driven microvascular remodeling and cardiac dysfunction are yet to be explored.

20‐Hydroxyeicosatetraenoic acid (20‐HETE) is a cytochrome P450‐derived arachidonate metabolite that has been shown to increase smooth muscle contractions and proliferation, stimulate endothelial dysfunction and promote hypertension. We examined if 20‐HETE contributes to vascular remodeling in androgen‐induced hypertension. In Sprague‐Dawley (SD) rats treated with 5α‐dihydrotestosterone (DHT), the increase in blood pressure (BP) is prevented by 20‐HETE inhibitor, HET0016, or 20‐HETE antagonist, 20–6,15‐HEDE. Likewise, inhibition of 20‐HETE's biosynthesis or activity abrogated DHT‐induced remodeling in renal interlobar arteries. In cyp4a14−/− mice, which display androgen‐driven and 20‐HETE‐dependent hypertension, treatment with 20–6,15‐HEDE abolished remodeling of renal interlobar arteries decreasing media thickness from 23.67±0.88 to 14.56±0.59μm and M/L from 0.29±0.03 to 0.17±0.01. To assess whether 20‐HETE induces vascular remodeling independent of BP increase, SD rats were administered reserpine (100μg/kg/day) and DHT for 21 days. Reserpine prevented BP elevation but did not affect vascular remodeling; under these conditions, treatment with 20–6,15‐HEDE attenuated vascular remodeling. This study demonstrates that 20‐HETE is a key regulator of vascular remodeling in androgen‐induced hypertension; its effect is independent of BP elevation.

20-hydroxyeicosatetraenoic acid (20-HETE), a cytochrome P450-arachidonic acid metabolite in the microcirculation, increases smooth muscle contraction and proliferation, stimulates endothelial dysfunction and activation and promotes hypertension that is dependent, in part, on the renin angiotensin system (RAS). We showed that in cultured human microvascular endothelial cells, 20-HETE increases angiotensin converting enzyme (ACE) mRNA by 3.1-fold (± 0.16; p<0.05), ACE protein by 4.2-fold (±0.99; p<0.05) and cellular and extracellular ACE activity by 2.2-fold (±0.09; p<0.05) and 1.96-fold (±0.16; p<0.05), respectively. The contribution of ACE to vascular 20-HETE-mediated microvascular remodeling in hypertension was assessed using the Cyp4a12 transgenic mouse in which the expression of the Cyp4a12-20-HETE synthase is driven by a tetracyclin (doxycycline, DOX)-sensitive promoter. Treatment of Cyp4a12tg mice with DOX increased blood pressure (133±6 vs. 107±3 mmHg; p<0.05) and remodeling of renal resistance arteries (M/L, 0.15±0.01 vs. 0.07±0.01; p<0.05); these increases were abrogated by co-treatment with the 20-HETE antagonist, 20-HEDGE. Renal ACE protein expression was significantly higher in DOX-treated (1.6 ± 0.17 fold; p<0.05) as compared to untreated Cyp4a12tg mice; co-treatment with 20-HEDGE prevented the increase in ACE expression. Lisinopril treatment of Cyp4a12tg mice concurrently receiving DOX prevented the blood pressure increase (133±6 vs. 104±2 mmHg; p<0.05) but did not interfere with renal microvascular 20-HETE production (1.05±0.18 vs 1.09±0.30 ng/mg). Co-treatment with lisinopril and DOX attenuated but did not prevent remodeling of renal microvessels (M/L, 0.07±0.0 vs. 0.15±0.01 vs. 0.11±0.01; p<0.05 in water, DOX and DOX+Lisinopril, respectively). In contrast, co-treatment with 20-HEDGE prevented DOX-induced remodeling of resistance arteries of Cyp4a12tg mice. This study demonstrates that 20-HETE is a key determinant of microvascular remodeling in DOX-induced Cyp4a12tg hypertensive mice. 20-HETE’s mechanism only partially relies on activation of the RAS. Thus, the 20-HETE-driven microvascular remodeling does not fully depend on the upregulation of ACE and elevation of blood pressure.

Objective— 20-hydroxyeicosatetraenoic acid (20-HETE) promotes endothelial dysfunction by uncoupling endothelial NO synthase, stimulating O 2 − production, and reducing NO bioavailability. Moreover, 20-HETE–dependent vascular dysfunction and hypertension are associated with upregulation of the renin–angiotensin system This study was undertaken to examine the contribution of renin–angiotensin system to 20-HETE actions in the vascular endothelium. Methods and Results— In endothelial cells, 20-HETE induced angiotensin-converting enzyme (ACE) mRNA levels and increased ACE protein and activity by 2- to 3-fold; these effects were negated with addition of the 20-HETE antagonist, 20-hydroxyeicosa-6(Z),15(Z)-dienoic acid (20 HEDE). 20-HETE induced ACE expression was protein kinase C independent and epidermal growth factor receptor tyrosine kinase and IκB kinase β dependent. ACE short interfering RNA abolished 20-HETE–mediated inhibition of NO production and stimulation of O 2 − generation, whereas angiotensin II type 1 receptor short interfering RNA attenuated these effects by 40%. 20-HETE–stimulated O 2 − production was negated by 20-HEDE and was attenuated by lisinopril and losartan. Importantly, 20-HETE–mediated impairment of acetylcholine-induced relaxation in rat renal interlobar arteries was also attenuated by lisinopril and losartan. Conclusion— These results indicate that ACE and angiotensin II type 1 receptor activation contribute to 20-HETE–mediated endothelial cell and vascular dysfunction and further enforce the notion that excessive production of 20-HETE within the vasculature leads to hypertension via mechanisms that include the induction of endothelial ACE, thus, perpetuating an increase in vascular angiotensin which, together with 20-HETE, promotes vascular dysfunction.

20-hydroxyeicosatetraenoic acid (20-HETE), a cytochrome P450 derived arachidonic acid metabolite, is manufactured in the microcirculation and shown to sensitize the smooth muscle to constrictor stimuli and cause endothelial activation and dysfunction. Increased vascular production of 20-HETE promotes hypertension that is dependent, in part, on the renin angiotensin system. Microarray analysis of endothelial cells treated with 20-HETE revealed a five-fold upregulation of angiotensin converting enzyme (ACE). In cultured human microvascular endothelial cells (HMVEC), 20-HETE (5 nM) induced ACE mRNA by 3.1-fold (± 0.16 p<0.05), increased ACE protein levels by 4.2-fold (±0.99 p<0.05) and ACE activity by 2-fold (±0.23 p<0.05). These effects were abrogated by co-treatment with 20-HEDE, a 20-HETE antagonist. 20-HETE induction of ACE mRNA was abolished by inhibitors of EGFR-tyrosine kinase, MAPK and IKKβ activation but was not affected by PKC inhibition. Moreover, transfection of cells with IKKβ siRNA prevented 20-HETE from inducing ACE mRNA. Collectively, theses results suggest a role for 20-HETE as a regulator of endothelial ACE. This regulatory activity impacts vascular function since downregulation of ACE in endothelial cells treated with siRNA exogenous 20-HETE from inhibiting NO synthesis and stimulating O 2 - production. This study demonstrates that induction of ACE expression and activity is critical to the actions of 20-HETE on endothelial cell function, further implicating the induction of ACE and activation of RAS as a key mechanism by which excessive production of 20-HETE within the vasculature leads to hypertension.

20-Hydroxyeicosatetraenoic acid (20-HETE) promotes smooth muscle contraction and proliferation, endothelial dysfunction and activation and hypertension. We have previously demonstrated that 20-HETE mediates androgen-induced hypertension. This study examines if 20-HETE contributes to vascular remodeling in androgen-induced hypertension. Sprague-Dawley rats were treated with vehicle or 5α-dihydrotestosterone (DHT) with and without the 20-HETE synthesis inhibitor (HET0016, 10mg/kg/day) for 14 days. Media-to-lumen ratio (M:L) in renal interlobar arteries from DHT-treated rats was higher (P<0.05) than vehicle-treated rats (0.21±0.01 vs. 0.15±0.02). This was prevented by HET0016 (0.14±0.01). Arteries from DHT-treated rats had increased (p<0.05) collagen type IV that was attenuated by HET0016. To assess whether 20-HETE induces vascular remodeling independent of blood pressure (BP) increase, reserpine (100 μg/kg/day) was administered to DHT- and vehicle-treated rats for 21 days. DHT increased BP (133.7±2.4 vs. 101.40±0.40 mmHg). Reserpine prevented this BP increase (104.20±1.30 mmHg) but had no effect on DHT-induced increase in M:L ratio (0.19±0.02) or in collagen I/IV deposition. These results suggest that DHT-mediated vascular remodeling is 20-HETE-dependent and that 20-HETE may contribute to DHT-induced vascular remodeling independent of BP elevation. Whether 20-HETE induces vascular remodeling in a DHT-independent manner was also examined. Cyp4a12 transgenic mice were treated with doxycycline (DOX) for 42 days to upregulate the cyp4a12 expression. BP of DOX-treated cyp4a12tg mice significantly increased compared to vehicle (139.59±4.06 vs. 92.25±5.25 mmHg) and 20-6,15-HEDE abolished BP increase (88.63±1.13 mmHg). Media thickness and M:L ratio significantly increased in DOX-treated group compared to vehicle (23.40±1.15 vs. 16.25±0.83μm; 0.39±0.04 vs. 0.23±0.02) and decreased by co-treatment with 20-6,15-HEDE (18.42±1.53μm; 0.28±0.03). These results indicate that 20-HETE can induce vascular remodeling in the absence of androgen.