Abstract 019: Vascular Smooth Muscle ADAM17 Contributes To Angiotensin II-induced Abdominal Aortic Aneurysm Formation But Not Hypertension In Mice

Hypertension ◽  
2014 ◽  
Vol 64 (suppl_1) ◽  
Author(s):  
Toshiyuki Tsuji ◽  
Takehiko Takayanagi ◽  
Katherine Elliott ◽  
Takashi Obama ◽  
Kevin Crawford ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Smooth Muscle ◽  
Abdominal Aortic Aneurysm ◽  
Angiotensin Ii ◽  
Aortic Aneurysm ◽  
Vascular Smooth Muscle ◽  
Saline Infusion ◽  
Internal Diameter ◽  
Egfr Activation ◽  
Abdominal Aortic

Enhancement of the renin angiotensin II (AngII) system has been implicated in the development of abdominal aortic aneurysm (AAA). However, detailed molecular mechanism(s) by which AngII promotes AAA remain uncertain. We have demonstrated the critical role of a metalloprotease, ADAM17, in AngII-induced EGFR transactivation and subsequent hypertrophy in vascular smooth muscle cells (VSMC). In caveolin 1-/- mice, AAA formation induced by AngII plus beta-aminopropionitrile (BAPN), a lysyl oxidase inhibitor, was attenuated. The attenuation of AAA formation was associated with suppression of ADAM17 induction and EGFR activation. Others have reported that systemic ADAM17 silencing attenuated CaCl2-induced AAA formation in mice. However, the cell type specific mechanism that is mediating the deleterious effect of ADAM17 in AAA is not well understood. Here, we tested our hypothesis that VSMC ADAM17 activation is required for AngII-promoted AAA formation using ADAM17flox/flox mice bred with sm22a Cre mice. 8 week old mice were co-infused with AngII 1000 ng/kg/min (4w) and BAPN 150 mg/kg/day (2w) or control saline (4w), and AAA formation was evaluated by echo (internal diameter) and measurement (external diameter) of the aortae. In control Cre-/- mice with the co-infusion, 52.4% (11/21) were dead due to aortic rupture/dissection. All surviving Cre-/- mice with co-infusion had AAA with max external/internal diameter (mm) of 2.18±0.55/1.75±0.33 vs 1.01±0.22/1.06±0.02 with saline infusion (p<0.01). In contrast, VSMC ADAM17 deficient Cre+/- with co-infusion did not die or develop AAA. The max external/internal diameter (mm) of AA in Cre+/- with co-infusion was 1.03±0.11/1.05±0.05 vs 1.01±0.12/1.27±0.21 with saline infusion. In contrast, both Cre-/- and +/- mice with the co-infusion developed hypertension assessed by telemetry (MAP mmHg: 161±15 vs 154±12). The ADAM17 deletion was also associated with less EGFR activation, ER/oxidative stress and extravascular fibrosis/matrix deposition. In conclusion, VSMC ADAM17 appears to be a critical metalloprotease contributing to AAA formation but not hypertension induced by AngII + BAPN. The mechanism by which VSMC ADAM17 promotes AAA seems to involve activation of EGFR and induction of ER/oxidative stress.

Abstract 099: EGF Receptor Inhibitor Erlotinib Prevented Abdominal Aortic Aneurysm But Not Hypertension Induced By Angiotensin II Plus Beta-aminopropionitrile

Hypertension ◽  
2014 ◽  
Vol 64 (suppl_1) ◽  
Author(s):  
Toshiyuki Tsuji ◽  
Takashi Obama ◽  
Yamato Fukuda ◽  
Katherine Elliott ◽  
Satoru Eguchi
Keyword(s):  
Oxidative Stress ◽  
Abdominal Aortic Aneurysm ◽  
Angiotensin Ii ◽  
Aortic Aneurysm ◽  
Egf Receptor ◽  
Internal Diameter ◽  
External Diameter ◽  
Matrix Deposition ◽  
Egfr Activation ◽  
Abdominal Aortic

Enhancement of the renin angiotensin II (AngII) system has been implicated in the development of abdominal aortic aneurysm (AAA). However, detailed molecular mechanism(s) by which AngII promotes AAA remain uncertain. We have demonstrated the critical role of a metalloprotease, ADAM17, in AngII-induced EGF receptor (EGFR) transactivation and subsequent hypertrophy in vascular smooth muscle cells (VSMC). In caveolin 1-/- mice, AAA formation induced by AngII plus beta-aminopropionitrile (BAPN), a lysyl oxidase inhibitor, was attenuated. The attenuation of AAA formation was associated with suppression of ADAM17 induction and EGFR activation. Others have reported that systemic ADAM17 silencing attenuated CaCl2-induced AAA formation in mice. We hypothesized that pharmacological inhibition of EGFR may prevent AAA but not hypertension in mice co-infused with Ang II and BAPN via suppression of ER/oxidative stress. To test this hypothesis, 8 week old mice were co-treated with AngII 1000 ng/kg/min (4 weeks) and BAPN 150 mg/kg/day (2weeks) with or without erlotinib (8 mg/kg/day), and AAA formation was evaluated by echo (internal diameter) and measurement (external diameter) of the aortae. In mice with the co-infusion, 64.3% (9/14) were dead due to aortic rupture/dissection. All surviving mice with co-infusion had AAA with max external/internal diameter (mm) of 2.12±0.31/2.06±0.47 vs 1.01±0.22/1.06±0.02 with saline infusion (p<0.01). In contrast, erlotinib-treated mice with co-infusion did not die or develop AAA. The max external/internal diameter (mm) of AA in this treatment was 1.19±0.18/1.06±0.10. In contrast, both erlotinib-treated and non-treated mice with the co-infusion developed hypertension assessed by telemetry (MAP mmHg: 147±7 vs 151±12). The EGFR inhibition was also associated with lack of EGFR activation, ADAM17 induction, ER/oxidative stress and extravascular fibrosis/matrix deposition. In conclusion, vascular EGFR activation appears to contribute to AAA formation but not hypertension induced by AngII plus BAPN. The mechanism by which EGFR promotes AAA seems to involve induction of ER stress and oxidative stress.

Abstract 534: Deficiency of Protease-activated Receptor 2 Attenuates Angiotensin II-induced Abdominal Aortic Aneurysm Independent of Vascular Smooth Muscle Cell Tissue Factor

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
David E Hall ◽  
Adrien Mann ◽  
Shannon M Jones ◽  
Nigel Mackman ◽  
A. Phillip Owens
Keyword(s):  
Smooth Muscle ◽  
Abdominal Aortic Aneurysm ◽  
Angiotensin Ii ◽  
Aortic Aneurysm ◽  
Vascular Smooth Muscle ◽  
Tissue Factor ◽  
Factor Xa ◽  
Male Mice ◽  
Abdominal Aortic ◽  
Protease Activated Receptor 2

Objective: Tissue factor (TF) is constitutively expressed in subendothelial cells, including vascular smooth muscle cells (VSMCs), and maintains hemostasis. The TF/factor VIIa complex as well as factor Xa have been shown to activate protease-activated receptor 2 (PAR-2). We and others have shown that TF/FVIIa-PAR-2 signaling induces migration of VSMCs in vitro and this is reduced in TF and PAR-2 deficient cells. We previously demonstrated C57BL/6 mice with 1% of normal TF levels (Low TF mice) had increased suprarenal abdominal aortic diameter and incidence of abdominal aortic aneurysm (AAA) compared to littermate controls. However, the source of cellular TF and whether signaling occurred through PAR-2 has not been examined. Our objective was to determine the importance of VSMC-specific deletion of TF and PAR-2 deficiency on the etiology of AAA. Methods and Results: VSMC-specific TF deficiency was evaluated on a low-density lipoprotein receptor deficient (Ldlr -/- ) background. Male mice were fed a fat-enriched diet (21% milk fat) and infused with angiotensin II (AngII; 1,000 ng/kg/min) for 28 days. Ldlr -/- /TF flox/flox SM22αCre + mice had increased abdominal aortic luminal diameters (Cre + : 1.92 ± 0.16 (n = 12); Cre - : 1.22 ± 0.03 mm (n = 10); P = 0.001) and incidence of AAA (100% vs. 50%; P = 0.01) compared to Cre - littermates. Next, we determined the effects of PAR-2 deficiency in AAA. Ldlr -/- /PAR-2 +/+ (n = 12) and Ldlr -/- /PAR-2 -/- (n = 15) male mice were fed a fat-enriched diet and infused with AngII for 28 days. PAR-2 deficiency attenuated abdominal aortic luminal diameters (PAR-2 +/+ : 1.78 ± 0.06 mm; PAR2 -/- : 1.17 ± 0.03 mm; P = 0.001) and incidence of AAA (84% versus 40%; P = 0.048) when compared to littermate controls. Total plasma cholesterol concentrations, lipoprotein cholesterol distributions, or increased systolic blood pressure was not different between groups. Conclusion: These results suggest that TF limits AAA growth and incidence via VSMCs in a PAR-2-independent manner. To verify this hypothesis, studies are currently underway to determine the effect of Factor Xa (FXa) inhibitors in PAR-2 deficient mice.

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

Hypertension ◽  
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.

scholarly journals Kallistatin limits abdominal aortic aneurysm by attenuating generation of reactive oxygen species and apoptosis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Smriti Murali Krishna ◽  
Jiaze Li ◽  
Yutang Wang ◽  
Corey S. Moran ◽  
Alexandra Trollope ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Smooth Muscle ◽  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Vascular Smooth Muscle ◽  
Sirtuin 1 ◽  
Abdominal Aortic ◽  
Markers Of Oxidative Stress ◽  
Muscle Cell Apoptosis ◽  
And Oxidative Stress

AbstractInflammation, vascular smooth muscle cell apoptosis and oxidative stress are believed to play important roles in abdominal aortic aneurysm (AAA) pathogenesis. Human kallistatin (KAL; gene SERPINA4) is a serine proteinase inhibitor previously shown to inhibit inflammation, apoptosis and oxidative stress. The aim of this study was to investigate the role of KAL in AAA through studies in experimental mouse models and patients. Serum KAL concentration was negatively associated with the diagnosis and growth of human AAA. Transgenic overexpression of the human KAL gene (KS-Tg) or administration of recombinant human KAL (rhKAL) inhibited AAA in the calcium phosphate (CaPO4) and subcutaneous angiotensin II (AngII) infusion mouse models. Upregulation of KAL in both models resulted in reduction in the severity of aortic elastin degradation, reduced markers of oxidative stress and less vascular smooth muscle apoptosis within the aorta. Administration of rhKAL to vascular smooth muscle cells incubated in the presence of AngII or in human AAA thrombus-conditioned media reduced apoptosis and downregulated markers of oxidative stress. These effects of KAL were associated with upregulation of Sirtuin 1 activity within the aortas of both KS-Tg mice and rodents receiving rhKAL. These results suggest KAL-Sirtuin 1 signalling limits aortic wall remodelling and aneurysm development through reductions in oxidative stress and vascular smooth muscle cell apoptosis. Upregulating KAL may be a novel therapeutic strategy for AAA.

scholarly journals SM22α Loss Contributes to Apoptosis of Vascular Smooth Muscle Cells via Macrophage-Derived circRasGEF1B

2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Pin Lv ◽  
Ya-Juan Yin ◽  
Peng Kong ◽  
Li Cao ◽  
Hao Xi ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Vascular Smooth Muscle ◽  
Inflammatory Cell ◽  
Activated Macrophages ◽  
Abdominal Aortic ◽  
Specific Manner ◽  
Higher Sensitivity

Vascular smooth muscle cell (VSMC) apoptosis is a major defining feature of abdominal aortic aneurysm (AAA) and mainly caused by inflammatory cell infiltration. Smooth muscle (SM) 22α prevents AAA formation through suppressing NF-κB activation. However, the role of SM22α in VSMC apoptosis is controversial. Here, we identified that SM22α loss contributed to apoptosis of VSMCs via activation of macrophages. Firstly, deficiency of SM22α enhanced the interaction of VSMCs with macrophages. Macrophages were retained and activated by Sm22α-/- VSMCs via upregulating VCAM-1 expression. The ratio of apoptosis was increased by 1.62-fold in VSMCs treated with the conditional media (CM) from activated RAW264.7 cells, compared to that of the control CM ( P < 0.01 ), and apoptosis of Sm22α-/- VSMCs was higher than that of WT VSMCs ( P < 0.001 ). Next, circRasGEF1B from activated macrophages was delivered into VSMCs promoting ZFP36 expression via stabilization of ZFP36 mRNA. Importantly, circRasGEF1B, as a scaffold, guided ZFP36 to preferentially bind to and decay Bcl-2 mRNA in a sequence-specific manner and triggered apoptosis of VSMCs, especially in Sm22α-/- VSMCs. These findings reveal a novel mechanism by which the circRasGEF1B-ZFP36 axis mediates macrophage-induced VSMC apoptosis via decay of Bcl-2 mRNA, whereas Sm22α-/- VSMCs have a higher sensitivity to apoptosis.

Abstract 279: Role of Caveolin-1 in Abdominal Aortic Aneurysm induced by Angiotensin II

2013 ◽  
Vol 33 (suppl_1) ◽  
Author(s):  
Takehiko Takayanagi ◽  
Kevin Crawford ◽  
Tomonori Kobayashi ◽  
Victor Rizzo ◽  
Satoru Eguchi
Keyword(s):  
Oxidative Stress ◽  
Abdominal Aortic Aneurysm ◽  
Angiotensin Ii ◽  
Aortic Aneurysm ◽  
Egf Receptor ◽  
Critical Role ◽  
Membrane Microdomains ◽  
Structural Protein ◽  
Caveolin 1 ◽  
Abdominal Aortic

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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