Reduced Nhe1 (Na
            +
            -H
            +
            Exchanger-1) Function Protects ApoE-Deficient Mice From Ang II (Angiotensin II)–Induced Abdominal Aortic Aneurysms

IgE-mediated activation of Nhe1 (Na + -H + exchanger-1) induces aortic cell extracellular acidification and promotes cell apoptosis. A pH-sensitive probe pHrodo identified acidic regions at positions of macrophage accumulation, IgE expression, and cell apoptosis in human and mouse abdominal aortic aneurysm (AAA) lesions. Ang II (angiotensin II)–induced AAA in Nhe1-insufficient Apoe −/− Nhe1 +/− mice and Apoe −/− Nhe1 +/+ littermates tested Nhe1 activity in experimental AAA, because Nhe1 −/− mice develop ataxia and epileptic-like seizures and die early. Nhe1 insufficiency reduced AAA incidence and size, lesion macrophage and T-cell accumulation, collagen deposition, elastin fragmentation, cell apoptosis, smooth muscle cell loss, and MMP (matrix metalloproteinase) activity. Nhe1 insufficiency also reduced blood pressure and the plasma apoptosis marker TCTP (translationally controlled tumor protein) but did not affect plasma IgE. While pHrodo localized the acidic regions to macrophage clusters, IgE expression, and cell apoptosis in AAA lesions from Apoe −/− Nhe1 +/+ mice, such acidic areas were much smaller in lesions from Apoe −/− Nhe1 +/− mice. Nhe1-FcεR1 colocalization in macrophages from AAA lesions support a role of IgE-mediated Nhe1 activation. Gelatin zymography, immunoblot, and real-time polymerase chain reaction analyses demonstrated that Nhe1 insufficiency reduced the MMP activity, cysteinyl cathepsin expression, IgE-induced apoptosis, and NF-κB activation in macrophages and blocked IgE-induced adhesion molecule expression in endothelial cells. A near-infrared fluorescent probe (LS662) together with fluorescence reflectance imaging of intact aortas showed reduced acidity in AAA lesions from Nhe-1-insufficient mice. This study revealed extracellular acidity at regions rich in macrophages, IgE expression, and cell apoptosis in human and mouse AAA lesions and established a direct role of Nhe1 in AAA pathogenesis.

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Effects of long-term chloroquine administration on the natural history of aortic aneurysms in mice

Canadian Journal of Physiology and Pharmacology ◽

10.1139/cjpp-2015-0068 ◽

2015 ◽

Vol 93 (8) ◽

pp. 641-648 ◽

Cited By ~ 8

Author(s):

Azza Ramadan ◽

Mark D. Wheatcroft ◽

Adrian Quan ◽

Krishna K. Singh ◽

Fina Lovren ◽

...

Keyword(s):

Natural History ◽

Thrombus Formation ◽

Aortic Aneurysms ◽

Ang Ii ◽

Abdominal Aortic ◽

Suprarenal Aorta ◽

History Of ◽

Categorical Distribution

Autophagy regulates cellular homeostasis and integrates the cellular pro-survival machinery. We investigated the role of autophagy in the natural history of murine abdominal aortic aneurysms (AAA). ApoE−/− mice were implanted with saline- or angiotensin II (Ang-II)-filled miniosmotic pumps then treated with either the autophagy inhibitor chloroquine (CQ; 50 mg·(kg body mass)–1·day–1, by intraperitoneal injection) or saline. Ang-II-elicited aneurysmal expansion of the suprarenal aorta coupled with thrombus formation were apparent 8 weeks later. CQ had no impact on the incidence (50% for Ang-II compared with 46.2% for Ang-II + CQ; P = NS) and categorical distribution of aneurysms. The markedly reduced survival rate observed with Ang-II (57.1% for Ang-II compared with 100% for saline; P < 0.05) was unaffected by CQ (61.5% for Ang-II + CQ; P = NS compared with Ang-II). CQ did not affect the mean maximum suprarenal aortic diameter (1.91 ± 0.19 mm for Ang-II compared with 1.97 ± 0.21 mm for Ang-II + CQ; P = NS). Elastin fragmentation, collagen accumulation, and smooth muscle attrition, which were higher in Ang-II-treated mice, were unaffected by CQ treatment. Long-term CQ administration does not affect the natural history and prognosis of experimental AAA, suggesting that global loss of autophagy is unlikely to be a causal factor in the development of aortic aneurysms. Manipulation of autophagy as a mechanism to reduce AAA may need re-evaluation.

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Abstract 598: Deletion of Microsomal PGE Synthase-1 Decreases Oxidative Stress and Protects Against Abdominal Aortic Aneurysm Formation in Angiotensin II-Infused Mice

Circulation ◽

10.1161/circ.116.suppl_16.ii_108-d ◽

2007 ◽

Vol 116 (suppl_16) ◽

Author(s):

Miao Wang ◽

Jane Stubbe ◽

Eric Lee ◽

Wenliang Song ◽

Emanuela Ricciotti ◽

...

Keyword(s):

Oxidative Stress ◽

Angiotensin Ii ◽

Low Density Lipoprotein ◽

Density Lipoprotein ◽

Aortic Aneurysms ◽

Ang Ii ◽

Abdominal Aortic ◽

Density Lipoprotein Receptor ◽

The Impact

Microsomal (m) prostaglandin (PG) E 2 synthase(S)-1, an enzyme that catalyzes the isomerization of the cyclooxygenase (COX) product, PGH 2 , into PGE 2 , is a major source of PGE 2 in vivo . mPGES-1 deletion in mice was found to modulate experimentally evoked pain and inflammation and atherogenesis is retarded in mPGES-1 knockout (KO) mice. The impact of mPGES-1 deletion on formation of angiotensin II (Ang II)-induced abdominal aortic aneurysms (AAA) was studied in mice lacking the low density lipoprotein receptor (LDLR −/− ). AngII infusion increased aortic macrophage recruitment and nitrotyrosine staining while upregulating both mPGES-1 and COX-2 and urinary excretion of the major metabolite of PGE 2 (PGE-M). Deletion of mPGES-1 decreased both the incidence and severity of AAA and depressed excretion of both PGE-M and 8, 12-iso-iPF 2a -VI, which reflects lipid peroxidation in vivo . While Ang II infusion augmented prostaglandin biosynthesis, deletion of mPGES-1 resulted in rediversion to PGD 2 , reflected by its major urinary metabolite. However, deletion of the PGD 2 receptor, DP1, did not affect AAA in Ang II infused LDLR −/− mice. These observations indicate that deletion of mPGES-1 protects against AAA formation by AngII in hyperlipidemic mice, perhaps by decreasing oxidative stress. Inhibition of mPGES-1 may represent an effective treatment to limit aneurysm occurrence and expansion.

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Erratum to “The Role of a Selective P2Y6 Receptor Antagonist, MRS2578, on the Formation of Angiotensin II-Induced Abdominal Aortic Aneurysms”

BioMed Research International ◽

10.1155/2020/8569421 ◽

2020 ◽

Vol 2020 ◽

pp. 1-1

Author(s):

Xiao Du ◽

Shilan Zhang ◽

Qunyan Xiang ◽

Jingyuan Chen ◽

Feng Tian ◽

...

Keyword(s):

Angiotensin Ii ◽

Receptor Antagonist ◽

Abdominal Aortic Aneurysms ◽

Aortic Aneurysms ◽

Abdominal Aortic ◽

P2y6 Receptor

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Macrophage 12(S)-HETE Enhances Angiotensin II–Induced Contraction by a BLT2 (Leukotriene B 4 Type-2 Receptor) and TP (Thromboxane Receptor)-Mediated Mechanism in Murine Arteries

Hypertension ◽

10.1161/hypertensionaha.121.17824 ◽

2021 ◽

Author(s):

Tamas Kriska ◽

Anja Herrnreiter ◽

Sandra L. Pfister ◽

Adeniyi Adebesin ◽

John R. Falck ◽

...

Keyword(s):

Angiotensin Ii ◽

Ang Ii ◽

Enhancing Effect ◽

Thromboxane Receptor ◽

Abdominal Aortic ◽

Induced Hypertension ◽

Arterial Constriction ◽

Thromboxane Receptor Antagonist ◽

Arterial Endothelial Cells

12/15-LO (12/15-lipoxygenase), encoded by Alox15 gene, metabolizes arachidonic acid to 12(S)-HETE (12-HETE). Macrophages are the major source of 12/15-LO among immune cells, and 12/15-LO plays a crucial role in development of hypertension. Global Alox15- or macrophage-deficient mice are resistant to Ang II (angiotensin II)–induced hypertension. This study tests the hypothesis that macrophage 12(S)-HETE contributes to Ang II–mediated arterial constriction and thus to development of Ang II–induced hypertension. Ang II constricted isolated abdominal aortic and mesenteric arterial rings. 12(S)-HETE (100 nmol/L) alone was without effect; however, it significantly enhanced Ang II–induced constriction. The presence of wild-type macrophages also enhanced the Ang II–induced constriction, while Alox15 −/− macrophages did not. Using this model, pretreatment of aortic rings with inhibitors, receptor agonists/antagonists, or removal of the endothelium, systematically uncovered an endothelium-mediated, Ang II receptor-2–mediated and superoxide-mediated enhancing effect of 12(S)-HETE on Ang II constrictions. The role of superoxide was confirmed using aortas from p47 phox−/− mice where 12(S)-HETE failed to enhance constriction to Ang II. In cultured arterial endothelial cells, 12(S)-HETE increased the production of superoxide, and 12(S)-HETE or Ang II increased the production of an isothromboxane-like metabolite. A TP (thromboxane receptor) antagonist inhibited 12(S)-HETE enhancement of Ang II constriction. Both Ang II–induced hypertension and the enhancing effect of 12(S)-HETE on Ang II contractions were eliminated by a BLT2 (leukotriene B 4 receptor-2) antagonist. These results outline a mechanism where the macrophage 12/15-LO pathway enhances the action of Ang II. 12(S)-HETE, acting on the BLT2, contributes to the hypertensive action of Ang II in part by promoting endothelial synthesis of a superoxide-derived TP agonist.

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The Role of a Selective P2Y6 Receptor Antagonist, MRS2578, on the Formation of Angiotensin II-Induced Abdominal Aortic Aneurysms

BioMed Research International ◽

10.1155/2020/1983940 ◽

2020 ◽

Vol 2020 ◽

pp. 1-15 ◽

Cited By ~ 1

Author(s):

Xiao Du ◽

Shilan Zhang ◽

Qunyan Xiang ◽

Jingyuan Chen ◽

Feng Tian ◽

...

Keyword(s):

Receptor Antagonist ◽

Aortic Aneurysms ◽

Control Group ◽

Placebo Control ◽

High Dose ◽

Ang Ii ◽

Abdominal Aortic ◽

Significant Difference ◽

Expression And Activity

Objective. The P2Y6 receptor has been shown to be involved in many cardiovascular diseases, including hypertension and atherosclerosis. The study is aimed at exploring the role of the P2Y6 receptor in Ang II-induced abdominal aortic aneurysm (AAA) formation in apolipoprotein E-deficient (apoE-/-) mice by using its selective antagonist. Methods. Male apoE-/- mice were fed with high-fat diet and infused with angiotensin (Ang) II (1000 ng/kg/min) for 4 weeks to induce AAA or saline as controls. Mice were divided into four groups: normal saline (NS, placebo control) group (n=8), Ang II+vehicle (Ang II) group (n=14), Ang II-low dose MRS2578 (Ang II+MRS-16 mg) group (n=14), and Ang II-high dose MRS2578 (Ang II+MRS-32 mg) group (n=14). Daily intraperitoneal injection with vehicle or MRS2578 was pretreated one week before Ang II infusion. On postoperative day 10, aorta imaging of each group was taken by ultrasonography. After 4 weeks of Ang II infusion, the excised aortas were processed for diameter measurement and quantification of aneurysm severity and tissue characteristics; the blood samples were collected for measurement of the lipid profile and levels of cytokines. Verhoeff’s Van Gieson (EVG) staining and immunochemistry staining were performed to evaluate disruption of the extracellular matrix (ECM) and infiltration of macrophages. Expression and activity of matrix metalloproteinases (MMPs) was measured by gelatin zymography. Results. Treatment with MRS2578 made no significant difference in AAA formation, and maximal aortic diameter yet caused higher AAA rupture-induced mortality from 7% (Ang II) to 21.4% (Ang II+MRS-16 mg) or 42.9% (Ang II+MRS-32 mg), respectively (p<0.05). Consistently, the severity of aneurysm tended to be more deteriorated in MRS2578-treated groups, especially the high-dosage group. The ratios of type III and IV aneurysm were much higher in the MRS2578-coadministered groups (p<0.05). Furthermore, histological analyses showed that administration of MRS2578 significantly increased infiltration of macrophages, expression of monocyte chemotactic protein 1 (MCP-1) and vascular cell adhesion molecule-1 (VCAM-1), and activities of MMP-2 and MMP-9 followed by aggravating degradation elastin in vivo (p<0.05). However, the multiple effects of MRS2578 on the development of AAA are independent of changes in systolic blood pressure and lipid profiles. Conclusions. The present study demonstrated that administration of MRS2578 exacerbated the progression and rupture of experimental AAA through promoting proinflammatory response and MMP expression and activity, which indicated a crucial role of the P2Y6 receptor in AAA development. Clinical Relevance. Purinergic P2Y receptors have attracted much attention since the P2Y12 receptor antagonist had been successfully applied in clinical practice. Elucidating the underlying mechanisms of AAA and exploring potential therapeutic strategies are essential to prevent its progression and reduce the mortality rate.

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Abstract 404: Cilostazol Attenuated Angiotensin II-Induced Abdominal Aortic Aneurysms in Apolipoprotein E--Deficient Mice

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.32.suppl_1.a404 ◽

2012 ◽

Vol 32 (suppl_1) ◽

Author(s):

Ryoko Umebayashi ◽

Haruhito A Uchida ◽

Hirofumi Makino

Keyword(s):

Angiotensin Ii ◽

Apolipoprotein E ◽

Ex Vivo ◽

Experimental Studies ◽

Gelatin Zymography ◽

Abdominal Aortic Aneurysms ◽

Aortic Aneurysms ◽

Maximal Diameter ◽

Abdominal Aortic ◽

Deficient Mice

Objective: Chronic infusion of angiotensin II (AngII) promotes development of abdominal aortic aneurysms (AAAs) in hypercholesterolemic mice. Previous studies have shown that local inflammation and increased oxidative stress plays an important role on formation of AAAs. Cilostazol, a phosphodiesterase-3 inhibitor with antiplatelet aggregation and vasodilatory effects, exerts vasoprotective effect by inhibiting inflammation and superoxide generation in several experimental studies. The purpose of this study was to evaluate whether cilostazol influenced AngII-induced AAAs. Methods and Results: Male apolipoprotein E deficient mice (8-12 weeks old) were fed with either normal diet or cilostazol-containing (0.1% wt/v) diet. After 1 week of cilostazol administration, mice were infused subcutaneously with either AngII (1,000 ng/kg/min, n = 16 -18) or saline (n = 5 - 6) by osmotic minipumps for 4 weeks. AngII equivalently increased systolic blood pressure, irrespective of cilostazol adminstration. Cilostazol had no effect on serum cholesterol concentrations, triglycerides, high-density lipoprotein-cholesterol, body weights, heart rates, and systolic blood pressures. Cilostazol did not affect ex vivo measurement of maximal diameter of abdominal aorta (0.88 ± 0.04 mm vs 0.88 ± 0.03 mm, n.s.) in saline infused-mice. AngII infusion significantly increased ex vivo maximal diameters of abdominal aortas but cilostazol administration attenuated (1.94 ± 0.16 mm vs 1.53 ± 0.17 mm, P < 0.05). In addition, gelatin zymography demonstrated that cilostazol diminished AngII-induced increase in aortic MMP-2 activity (P < 0.05). Conclusion: Cilostazol attenuated AngII-induced AAAs in male apolipoprotein E deficient mice.

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Inhibition of Peptidyl Arginine Deiminase 4-Dependent Neutrophil Extracellular Trap Formation Reduces Angiotensin II-Induced Abdominal Aortic Aneurysm Rupture in Mice

Frontiers in Cardiovascular Medicine ◽

10.3389/fcvm.2021.676612 ◽

2021 ◽

Vol 8 ◽

Author(s):

Ming Wei ◽

Xia Wang ◽

Yanting Song ◽

Di Zhu ◽

Dan Qi ◽

...

Keyword(s):

Abdominal Aortic Aneurysm ◽

Angiotensin Ii ◽

Aortic Aneurysm ◽

Tissue Injury ◽

Arginine Deiminase ◽

Tunel Staining ◽

Ang Ii ◽

Elastin Degradation ◽

Abdominal Aortic

Objective: Neutrophil infiltration plays an important role in the initiation and development of abdominal aortic aneurysm (AAA). Recent studies suggested that neutrophils could release neutrophil extracellular traps (NETs), leading to tissue injury in cardiovascular diseases. However, the role of NETs in AAA is elusive. This study aimed to investigate the role and underlying mechanism of NETs in AAA development.Methods and Results: An angiotensin II (Ang II) infusion-induced AAA model was established to investigate the role of NETs during AAA development. Immunofluorescence staining showed that citrullinated histone 3 (citH3), myeloperoxidase (MPO), and neutrophil elastase (NE) (NET marker) expressions were significantly increased in Ang II-infused ApoE−/− mice. The circulating double-stranded DNA (dsDNA) level was also elevated, indicating the increased NET formation during AAA. PAD4 inhibitor YW3-56 inhibited Ang II-induced NET formation. Disruption of NET formation by YW3-56 markedly reduced Ang II-induced AAA rupture, as revealed by decreased aortic diameter, vascular smooth muscle cell (VSMC) apoptosis, and elastin degradation. Apoptosis of VSMC was evaluated by TUNEL staining and Annexin V-FITC/PI staining through flow cytometry. Western blot and inhibition experiments revealed that NETs induced VSMC apoptosis via p38/JNK pathway, indicating that PAD4-dependent NET formation played an important role in AAA.Conclusions: This study suggests that PAD4-dependent NET formation is critical for AAA rupture, which provides a novel potential therapeutic strategy for AAA disease.

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Weight loss in obese C57BL/6 mice limits adventitial expansion of established angiotensin II-induced abdominal aortic aneurysms

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00961.2009 ◽

2010 ◽

Vol 298 (6) ◽

pp. H1932-H1938 ◽

Cited By ~ 15

Author(s):

Sara B. Police ◽

Kelly Putnam ◽

Sean Thatcher ◽

Frederique Batifoulier-Yiannikouris ◽

Alan Daugherty ◽

...

Keyword(s):

Weight Loss ◽

Angiotensin Ii ◽

Abdominal Aortic Aneurysms ◽

Aortic Aneurysms ◽

Stem Cell Marker ◽

Ang Ii ◽

Low Fat Diet ◽

Abdominal Aortic ◽

Induce Weight Loss ◽

Adipose Derived Stem Cell

Previous studies demonstrated that obesity increases inflammation in periaortic adipose tissue and promotes angiotensin II (ANG II)-induced abdominal aortic aneurysms (AAAs). We sought to determine whether weight loss of obese C57BL/6 mice would influence the progression of established AAAs. Male C57BL/6 mice were fed a high-fat diet (HF) for 4 mo and then infused with either saline or ANG II (1,000 ng·kg−1·min−1) for 3 mo. Mice with dilated suprarenal aortas at 28 days of ANG II infusion were designated to groups fed the HF (HF/HF) or a low-fat diet (LF; 10% kcal as fat; HF/LF) to induce weight loss for the last 2 mo of infusions. Suprarenal aortic lumen diameters of obese mice were increased by ANG II infusion at day 28 ( day 0: 1.03 ± 0.02; day 28: 1.86 ± 0.14 mm; P < 0.05), but did not progress with continued infusion in HF/HF mice. Moreover, aortic lumen diameters were not different between groups (HF/HF: 1.89 ± 0.15; HF/LF: 1.79 ± 0.18 mm). However, maximal diameters of excised AAAs were decreased with weight loss (HF/HF: 2.00 ± 0.11; HF/LF: 1.55 ± 0.13 mm; P < 0.05) and had reduced adventitial areas (HF/HF: 1.18 ± 0.10; HF/LF: 0.54 ± 0.02 mm2; P < 0.05). Neovascularization of aortic adventitias was strikingly decreased in HF/LF mice (HF/HF: 43 ± 5; HF/LF: 12 ± 2 endothelial cells/adventitial area; P < 0.05). ANG II-induced elevations in adipose mRNA abundance of CD105, an adipose-derived stem cell marker, were abolished with weight loss. These results demonstrate that weight loss limits adventitial expansion of ANG II-induced AAAs. Reduced neovascularization from weight loss may limit progression of AAAs.

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Testosterone Metabolite 6β‐Hydroxytestosterone Contributes to Angiotensin II‐Induced Abdominal Aortic Aneurysms in Apoe –/– Male Mice

Journal of the American Heart Association ◽

10.1161/jaha.120.018536 ◽

2021 ◽

Author(s):

Kamalika Mukherjee ◽

Ajeeth K. Pingili ◽

Purnima Singh ◽

Ahmad N. Dhodi ◽

Shubha R. Dutta ◽

...

Keyword(s):

Cytochrome P450 ◽

Risk Factor ◽

Angiotensin Ii ◽

Abdominal Aortic Aneurysms ◽

Aortic Aneurysms ◽

Ang Ii ◽

Male Mice ◽

Cytochrome P450 1B1 ◽

Abdominal Aortic ◽

Induced Hypertension

Background Sex is a prominent risk factor for abdominal aortic aneurysms (AAAs), and angiotensin II (Ang II) induces AAA formation to a greater degree in male than in female mice. We previously reported that cytochrome P450 1B1 contributes to the development of hypertension, as well as AAAs, in male mice. We also found that a cytochrome P450 1B1‐generated metabolite of testosterone, 6β‐hydroxytestosterone (6β‐OHT), contributes to Ang II‐induced hypertension and associated cardiovascular and renal pathogenesis in male mice. The current study was conducted to determine the contribution of 6β‐OHT to Ang II‐induced AAA development in Apoe –/– male mice. Methods and Results Intact or castrated Apoe –/– /Cyp1b1 +/+ and Apoe –/– /Cyp1b1 –/– male mice were infused with Ang II or its vehicle for 28 days, and administered 6β‐OHT every third day for the duration of the experiment. Abdominal aortas were then evaluated for development of AAAs. We observed a significant increase in the incidence and severity of AAAs in intact Ang II‐infused Apoe –/– /Cyp1b1 +/+ mice, compared with vehicle‐treated mice, which were minimized in castrated Apoe –/– /Cyp1b1 +/+ and intact Apoe –/– /Cyp1b1 –/– mice infused with Ang II. Treatment with 6β‐OHT significantly restored the incidence and severity of AAAs in Ang II‐infused castrated Apoe –/– /Cyp1b1 +/+ and intact Apoe –/– /Cyp1b1 –/– mice. However, administration of testosterone failed to increase AAA incidence and severity in Ang II‐infused intact Apoe –/– /Cyp1b1 –/– mice. Conclusions Our results indicate that the testosterone‐cytochrome P450 1B1‐generated metabolite 6β‐OHT contributes to Ang II‐induced AAA development in Apoe –/– male mice.

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