Urokinase-Type Plasminogen Activator Plays a Critical Role in Angiotensin II–Induced Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is a significant cause of mortality for adults aged >60 years. Accumulating evidence suggests that activation of the AT1 receptor by angiotensin II (AngII) in AAA formation. While several downstream signals and target proteins have been identified in this pathway, there is a huge void in our knowledge regarding the AngII-sensitive proximal events primarily responsible for AAA formation. We recently reported that caveolae membrane microdomains in vascular smooth muscle cells (VSMC) mediate a metalloprotease ADAM17-dependent EGF receptor (EGFR) transactivation which linked to vascular remodeling induced by AngII. Given that ADAM17 expression is one of the key features in AAA, we have tested our hypothesis that caveolin-1 (Cav1), a major structural protein of caveolae, in the vasculature plays a critical role for development of AAA via its regulation on ADAM17. 8 week old male Cav1-/- mice and the control C57Bl/6 wild-type (WT) mice were co-infused with AngII and BAPN, a lysyl oxidase inhibitor, to induce AAA. We found that Cav1-/- mice did not develop AAA compared to C57Bl/6 mice in spite of hypertension assessed by telemetry in both groups. This finding suggests that the AngII signaling essential for vascular contraction remains in place in Cav1-/- mice. We found an increased expression of ADAM17 and auto-phosphorylation of EGFR in WT abdominal aortae with aneurysms that were markedly attenuated in Cav1-/- mice infused with AngII+BAPN. Furthermore, Cav1-/- mice with the infusion showed less oxidative stress and ER stress than their WT counterparts as assessed by nitrotyrosine staining and KDEL/p-eIF2a staining, respectively. In conclusion, Cav1 and presumably vascular caveolae micro-domain appear to play a critical role in the formation of AAA in mice via regulation of the ADAM17/EGFR signaling axis and subsequent induction of ER/oxidative stress.

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IKK Epsilon Deficiency Attenuates Angiotensin II-Induced Abdominal Aortic Aneurysm Formation in Mice by Inhibiting Inflammation, Oxidative Stress, and Apoptosis

Oxidative Medicine and Cellular Longevity ◽

10.1155/2020/3602824 ◽

2020 ◽

Vol 2020 ◽

pp. 1-16

Author(s):

Hao Chai ◽

ZhongHao Tao ◽

YongChao Qi ◽

HaoYu Qi ◽

Wen Chen ◽

...

Keyword(s):

Abdominal Aortic Aneurysm ◽

Angiotensin Ii ◽

Aortic Aneurysm ◽

Molecular Mechanisms ◽

Critical Role ◽

Ang Ii ◽

Elastin Degradation ◽

Maximal Diameter ◽

Abdominal Aortic ◽

Primary Mouse

Abdominal aortic aneurysm (AAA) is a vascular disorder that is considered a chronic inflammatory disease. However, the precise molecular mechanisms involved in AAA have not been fully elucidated. Recently, significant progress has been made in understanding the function and mechanism of action of inhibitor of kappa B kinase epsilon (IKKε) in inflammatory and metabolic diseases. The angiotensin II- (Ang II-) induced or pharmacological inhibitors were established to test the effects of IKKε on AAA in vivo. After mice were continuously stimulated with Ang II for 28 days, morphologically, we found that knockout of IKKε reduced AAA formation and drastically reduced maximal diameter and severity. We also observed a decrease in elastin degradation and medial destruction, which were independent of systolic blood pressure or plasma cholesterol concentrations. Western blot analyses and immunohistochemical staining were carried out to measure IKKε expression in AAA tissues and cell lines. AAA phenotype of mice was measured by ultrasound and biochemical indexes. In zymography, immunohistology staining, immunofluorescence staining, and reactive oxygen species (ROS) analysis, TUNEL assay was used to examine the effects of IKKε on AAA progression in AAA mice. IKKε deficiency significantly inhibited inflammatory macrophage infiltration, matrix metalloproteinase (MMP) activity, ROS production, and vascular smooth muscle cell (VSMC) apoptosis. We used primary mouse aortic VSMC isolated from apolipoprotein E (Apoe) −/− and Apoe−/−IKKε−/− mice. Mechanistically, IKKε deficiency blunted the activation of the ERK1/2 pathway. The IKKε inhibitor, amlexanox, has the same impact in AAA. Our results demonstrate a critical role of IKKε in AAA formation induced by Ang II in Apoe−/− mice. Targeting IKKε may constitute a novel therapeutic strategy to prevent AAA progression.

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Abstract 47: Caveolin-1 is Critical for Abdominal Aortic Aneurysm Induced by Angiotensin II

Hypertension ◽

10.1161/hyp.62.suppl_1.a47 ◽

2013 ◽

Vol 62 (suppl_1) ◽

Author(s):

Takashi Obama ◽

Takehiko Takayanagi ◽

Kevin J Crawford ◽

Tomonori Kobayashi ◽

Victor Rizzo ◽

...

Keyword(s):

Oxidative Stress ◽

Smooth Muscle ◽

Abdominal Aortic Aneurysm ◽

Angiotensin Ii ◽

Aortic Aneurysm ◽

Vascular Smooth Muscle Cells ◽

Critical Role ◽

Ang Ii ◽

Caveolin 1 ◽

Abdominal Aortic

Abdominal aortic aneurysm (AAA) is a significant cause of mortality for adults aged >60 years. Accumulating evidence suggests a role of angiotensin II (Ang II) in abdominal aortic aneurysm (AAA) formation. However, the Ang II-sensitive proximal signaling events primarily responsible for AAA formation remain unclear. We recently reported that caveolin-1 (Cav1) enriched membrane microdomains in vascular smooth muscle cells (VSMC) mediate a metalloprotease ADAM17-dependent EGF receptor (EGFR) transactivation, which is linked to vascular remodeling induced by Ang II. Given that ADAM17 expression is one of the key features in AAA, we have tested our hypothesis that Cav1, a major structural protein of caveolae, plays a critical role for development of AAA by Ang II via regulation of ADAM17. 8 week old male Cav1-/- and the control C57Bl/6 wild-type mice (WT) were co-infused with Ang II (1 μg/kg/min) and β-aminopropionitrile (BAPN: 150mg/kg/day) for 4 weeks to induce AAA. In WT with the co-infusion, 58% (14/24) were dead due to aortic rupture/dissection. All surviving WT with co-infusion had AAA with max diameter (mm) of 2.6±0.18 vs 0.93±0.09 with saline infusion (p<0.01). In contrast, we found that Cav1-/- with co-infusion did not die or develop AAA. The max diameter (mm) of AAA in Cav1-/- with co-infusion was 1.0±0.04 vs 1.1±0.06 with saline infusion (n=7). In contrast, both WT and Cav1-/- with the co-infusion developed hypertension assessed by telemetry (MAP mmHg: 151±5 vs 161±7). We found an increased expression of ADAM17 by IHC and qPCR, and enhanced phosphorylation of EGFR by IHC in WT abdominal aortae with aneurysms. These events were markedly attenuated in Cav1-/- aorta with co-infusion (ADAM17/18S mRNAx10,000 = 3.08±0.71 vs 0.97±0.42 p<0.05, n=4). Furthermore, Cav1-/- aortae showed less ER and oxidative stress compared to WT aortae assessed by IHC. In addition, Cav1 silencing induced by adenovirus encoding Cav1 targeting siRNA embedded miRNA in cultured vascular smooth muscle cells prevented Ang II-induced ADAM17 induction and activation. In conclusion, Cav1 and presumably vascular caveolae microdomains appear to play a critical role in the formation of AAA by Ang II via regulation of the ADAM17/EGFR signaling and subsequent ER/oxidative stress.

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Urokinase-Type Plasminogen Activator Deficiency in Bone Marrow–Derived Cells Augments Rupture of Angiotensin II–Induced Abdominal Aortic Aneurysms

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvbaha.111.234997 ◽

2011 ◽

Vol 31 (12) ◽

pp. 2845-2852 ◽

Cited By ~ 34

Author(s):

Haruhito A. Uchida ◽

Aruna Poduri ◽

Venkateswaran Subramanian ◽

Lisa A. Cassis ◽

Alan Daugherty

Keyword(s):

Bone Marrow ◽

Angiotensin Ii ◽

Plasminogen Activator ◽

Abdominal Aortic Aneurysms ◽

Aortic Aneurysms ◽

Abdominal Aortic ◽

Type Plasminogen Activator ◽

Urokinase Type Plasminogen Activator ◽

Bone Marrow Derived Cells

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Abstract 25: Inducible Depletion of Calpain-2 Attenuates Angiotensin II-induced Cytoskeletal Structural Protein Destruction During Abdominal Aortic Aneurysm Development in Mice

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.36.suppl_1.25 ◽

2016 ◽

Vol 36 (suppl_1) ◽

Author(s):

Latha Muniappan ◽

Aida Javidan ◽

Weihua Jiang ◽

Jessica J Moorleghen ◽

Anju Balakrishnan ◽

...

Keyword(s):

Abdominal Aortic Aneurysm ◽

Angiotensin Ii ◽

Aortic Aneurysm ◽

Structural Integrity ◽

Critical Role ◽

Cysteine Proteases ◽

Filamin A ◽

Structural Protein ◽

Abdominal Aortic ◽

Calpain 2

Background and Objective: In abdominal aortic aneurysm (AAA) patients, structural integrity of the aortic wall is disrupted due to the dissociation of cytoskeletal structural proteins that bridge SMC contractile filaments with extracellular matrix by proteases. However, identity of functional proteases which target cytoskeletal structural linker proteins remain unknown. Recently, using the angiotensin II (AngII)-induced AAA model, we demonstrated that AngII significantly increased fragmentation of cytoskeletal structural protein, Filamin A, in AAAs. Further, using a pharmacological inhibitor and genetic deficient mice, we identified that calpain-2 (a class of calcium-activated, intracellular cysteine proteases) plays a critical role in AngII-induced AAA formation in mice. The purpose of this study was to determine the functional contribution of calpain-2 in AngII-induced cytoskeletal structural protein destruction during AAA development. Methods and Results: Calpain-2 floxed mice that were hemizygous for Cre-ERT2 in an LDLr -/- background were produced by breeding male Cre-ERT2 to female calpain-2 floxed mice. At 8 weeks of age, male Calp-2 x Cre-ERT2 (Cre+) and non-Cre littermates (Cre-) mice were injected with tamoxifen (25 mg/kg, i.p.) daily for 5 consecutive days. After 2 weeks, Western blot analyses showed a complete depletion of calpain-2 protein in the aorta from Cre+ mice compared to Cre- littermates. Male Cre+ and Cre- (N=12 each) mice were fed a Western diet and infused with saline or AngII (1,000 ng/kg/min) by osmotic minipumps for 2 weeks. AngII infusion significantly (P<0.05 vs saline) increased c-terminal fragmentation of cytoskeletal structural protein, talin and kinases such as integrin linked kinase-1 (ILK-1), and focal adhesion kinase in addition to filamin A. Inducible depletion of calpain-2 significantly (P<0.05; Cre+ vs Cre-) blunted AngII-induced fragmentation of talin, filamin A and ILK-1. Further siRNA mediated silencing of calpain-2 in aortic SMCs and fibroblasts significantly reduced AngII-induced fragmentation of filamin A and talin. Conclusion: These findings suggest that calpain-2 plays a critical role in AngII-induced cytoskeletal structural protein fragmentation during AAA development in mice.

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