Abstract MP01: Deacetylation Of Mitochondrial Cyclophilin D K166 Inhibits Cytokine-induced Oxidative Stress And Attenuates Hypertension

Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Sergey I Dikalov ◽  
Vladimir Mayorov ◽  
Daniel Fehrenbach ◽  
Mingfang Ao ◽  
Alexander Panov ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Angiotensin Ii ◽  
Vascular Function ◽  
Organ Damage ◽  
Cyclophilin D ◽  
Wild Type ◽  
End Organ Damage ◽  
Mitochondrial Superoxide ◽  
Vascular Oxidative Stress

We have previously reported that depletion Cyclophilin D (CypD), a regulatory subunit of mitochondrial permeability transition pore, improves vascular function and attenuates hypertension, however, specific regulation of CypD in hypertension is not clear. Analysis of human arterioles from hypertensive patients did not reveal alterations in CypD levels but showed 3-fold increase in CypD acetylation. We hypothesized that CypD-K166 acetylation promotes vascular oxidative stress and hypertension, and measures to reduce CypD acetylation can improve vascular function and reduce hypertension. Essential hypertension and animal models of hypertension are linked to inactivation of mitochondrial deacetylase Sirt3 by highly reactive lipid oxidation products, isolevuglandins (isoLGs), and supplementation of mice with mitochondria targeted scavenger of isoLGs, mito2HOBA, improves CypD deacetylation. To test the specific role of CypD-K166 acetylation, we developed CypD-K166R deacetylation mimic mutant mice. Mitochondrial respiration, vascular function and systolic blood pressure in CypD-K166R mice was similar to wild-type C57Bl/6J mice. Meanwhile, angiotensin II-induced hypertension was substantially attenuated in CypD-K166R mice (144 mmHg) compared with wild-type mice (161 mmHg). Angiotensin II infusion in wild-type mice significantly increased mitochondrial superoxide, impaired endothelial dependent relaxation, and reduced the level of endothelial nitric oxide which was prevented in angiotensin II-infused CypD-K166R mice. Hypertension is linked to increased levels of inflammatory cytokines TNFα and IL-17A promoting vascular oxidative stress and end-organ damage. We have tested if CypD-K166R mice are protected from cytokine-induced oxidative stress. Indeed, ex vivo incubation of aorta with the mixture of angiotensin II, TNFα and IL-17A (24 hours) increased mitochondrial superoxide by 2-fold in wild-type aortas which was abrogated in CypD-K166R mice. These data support the pathophysiological role of CypD acetylation in inflammation, oxidative stress and hypertensive end-organ damage. We propose that targeting CypD acetylation may have therapeutic potential in treatment of vascular dysfunction and hypertension.

Abstract P080: Mutation Of Lysine 68 To Arginine Mimics Deacetylation Of Mitochondrial Superoxide Dismutase, Protects From Vascular Oxidative Stress And Attenuates Angiotensin II-Induced Hypertension

Hypertension ◽  
2020 ◽  
Vol 76 (Suppl_1) ◽  
Author(s):  
Anna Dikalova ◽  
Liliya Tkachuk ◽  
Marcos G Lopez ◽  
Frederic T Billings ◽  
Sergey I Dikalov
Keyword(s):  
Oxidative Stress ◽  
Blood Pressure ◽  
Superoxide Dismutase ◽  
Angiotensin Ii ◽  
Wild Type ◽  
Mitochondrial Superoxide ◽  
Induced Hypertension ◽  
Lysine Residues ◽  
Vascular Oxidative Stress

By recent guidelines, almost one-half of adults have hypertension, and blood pressure is poorly controlled in a third of patients despite use of multiple drugs, likely due to mechanisms contributing to blood pressure elevation that are not affected by current treatments. Hypertension is linked to oxidative stress; however, common antioxidants are ineffective. We found that hypertension is associated with inactivation of key mitochondrial antioxidant, superoxide dismutase 2 (SOD2), due to acetylation of lysine residues at the catalytic center. The role of specific SOD2 lysine residues in hypertension, however, has not been defined. We proposed that inactivation of key intrinsic antioxidant, SOD2, in hypertension is linked to acetylation of Lysine 68, and mutation of K68 to Arginine mimics SOD2 deacetylation, inhibits vascular oxidative stress and attenuates angiotensin II-induced hypertension. To test this hypothesis, we have investigated SOD2 acetylation in arterioles from patients with essential hypertension and developed a new deacetylation mimic SOD2 mutant K68R mice (SOD2-K68R). Western blot analysis of arterioles isolated from human mediastinal fat showed 3-fold increase in SOD2 acetylation in hypertensive patients compared with normotensive subjects while SOD2 levels were not affected. To define the functional significance of K68 acetylation we performed studies in vivo in SOD2-K68R mice using angiotensin II model of vascular dysfunction and hypertension. Angiotensin II infusion in wild-type C57Bl/6J mice induced vascular inflammation and oxidative stress, and increased blood pressure to 160 mm Hg. Mutation of Lysine 68 to Arginine in SOD2-K68R mice completely prevented the increase in mitochondrial superoxide and significantly attenuated the angiotensin II induced hypertension (135 mm Hg). Angiotensin II and TNFα co-operatively induce SOD2 acetylation and hypertension. Treatment of wild-type aortas with angiotensin II and TNFα in organoid culture increased mitochondrial superoxide by 2-fold which was completely prevented in aortas isolated from SOD2-K68R mice. These data support an important role of SOD2-K68 acetylation in hypertension, and strategies to reduce mitochondrial acetylation may have therapeutic potential.

Abstract P618: Inactivation of Mitochondrial Deacetylase Sirt3 Promotes Vascular Oxidative Stress, Increases Endothelial Dysfunction and Exacerbates Hypertension

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Anna E Dikalova ◽  
Roman Uzhachenko ◽  
Hana A Itani ◽  
David G Harrison ◽  
Sergey Dikalov
Keyword(s):  
Oxidative Stress ◽  
Smooth Muscle ◽  
Endothelial Dysfunction ◽  
Ex Vivo ◽  
Fold Increase ◽  
Organ Damage ◽  
Ang Ii ◽  
Wild Type ◽  
Vascular Oxidative Stress

Endothelial dysfunction is associated with aging, diabetes, hyperlipidemia, obesity and these risk factors affect the expression and activity of the mitochondrial deacetylase Sirt3. Sirt3 activates major antioxidant SOD2 by deacetylation of specific lysine residues and Sirt3 depletion increases oxidative stress. We hypothesized that loss of vascular Sirt3 increases endothelial dysfunction, promotes hypertension and end organ damage. The role of vascular Sirt3 was studied in wild-type C57Bl/6J mice and tamoxifen-inducible smooth muscle specific Sirt3 knockout mice (Smc Sirt3 KO ) using angiotensin II model of hypertension (Ang II, 0.7 mg/kg/day). Western blot showed 30% reduction of vascular Sirt3 and 2-fold increase in SOD2 acetylation in Ang II-infused WT mice. We have tested if ex vivo treatment of aorta with Sirt3 activator resveratrol improves endothelial function. Indeed, ex vivo incubation with resveratrol (10 μM) significantly reduced SOD2 acetylation, diminished mitochondrial O 2 and increased endothelial NO to normal level while Sirt3-inactive analog dihydroresveratrol had no effect. Specific role of vascular Sirt3 was studied in Smc Sirt3 KO mice by crossing floxed Sirt3 mice with mice carrying gene for inducible cre in the vascular smooth muscle. Sirt3 deletion exacerbates hypertension (165 mm Hg vs 155 mm Hg in wild-type) and significantly increases mortality in Ang II-infused Smc Sirt3 KO mice (60% vs 10% in wild-type) associated with severe edema and aortic aneurysm (100% vs 20% in wild-type). Decrease of NO is a hallmark of endothelial dysfunction in hypertension due to vascular oxidative stress. Indeed, Ang II infusion increased vascular O 2 by 2-fold and reduced endothelial NO by 2-fold. Interestingly, Ang II infusion in Smc Sirt3 KO mice caused severe vascular oxidative stress (3-fold increase in O 2 ) and exacerbated endothelial dysfunction (4-fold decrease in NO). These data indicate that reduced vascular Sirt3 activity occurs in hypertension and this promotes vascular oxidative stress, increases endothelial dysfunction, exacerbates hypertension, increases end-organ-damage and mortality. It is conceivable that Sirt3 agonists and SOD2 mimetics may have therapeutic potential in cardiovascular disease.

Abstract 15061: Essential Hypertension is Linked to Acetylation of Mitochondrial Superoxide Dismutase and Deacetylation Mimetic Mutation of Lysine 68 to Arginine Protects From Oxidative Stress and Hypertension

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Anna Dikalova ◽  
Liliya Tkachuk ◽  
Marcos G Lopez ◽  
Frederic T Billings ◽  
Sergey Dikalov
Keyword(s):  
Oxidative Stress ◽  
Blood Pressure ◽  
Superoxide Dismutase ◽  
Essential Hypertension ◽  
Angiotensin Ii ◽  
Wild Type ◽  
Mitochondrial Superoxide ◽  
Induced Hypertension ◽  
Lysine Residues

Almost one-half of adults have hypertension, and blood pressure is poorly controlled in a third of patients despite use of multiple drugs, likely due to mechanisms contributing to blood pressure elevation that are not affected by current treatments. Hypertension is linked to oxidative stress; however, common antioxidants are ineffective. We found that hypertension is associated with inactivation of key mitochondrial antioxidant, superoxide dismutase 2 (SOD2), due to acetylation of lysine residues at the catalytic center. The role of specific SOD2 lysine residues in hypertension, however, has not been defined. Hypothesis: We proposed that inactivation of key intrinsic antioxidant, SOD2, in hypertension is linked to acetylation of Lysine 68, and mutation of K68 to Arginine mimics SOD2 deacetylation, inhibits vascular oxidative stress and attenuates angiotensin II-induced hypertension. To test this hypothesis, we have investigated SOD2 acetylation in arterioles from patients with essential hypertension and developed a new deacetylation mimic SOD2 mutant K68R mice (SOD2-K68R). Western blot of arterioles isolated from human mediastinal fat showed 3-fold increase in SOD2 acetylation in hypertensive patients compared with normotensive subjects while SOD2 levels were not affected. To define the functional significance of K68 acetylation we performed studies in vivo in SOD2-K68R mice using angiotensin II model of vascular dysfunction and hypertension. Angiotensin II infusion in wild-type C57Bl/6J mice induced vascular inflammation and oxidative stress, and increased blood pressure to 160 mm Hg. Mutation of Lysine 68 to Arginine in SOD2-K68R mice completely prevented the increase in mitochondrial superoxide and significantly attenuated the angiotensin II induced hypertension (135 mm Hg). Angiotensin II and TNFα co-operatively induce SOD2 acetylation and hypertension. Treatment of wild-type aortas with angiotensin II and TNFα in organoid culture increased mitochondrial superoxide by 2-fold which was completely prevented in aortas isolated from SOD2-K68R mice. Conclusions: These data support an important role of SOD2-K68 acetylation in hypertension and targeting Sirt3-mediated deacetylation of SOD2 may have therapeutic potential.

Abstract 070: AntagomiR-762 Prevents Angiotensin II Induced Aortic Fibrosis and Stiffening

Hypertension ◽  
2015 ◽  
Vol 66 (suppl_1) ◽  
Author(s):  
Kim Ramil C Montaniel ◽  
Jing Wu ◽  
Matthew R Bersi ◽  
Liang Xiao ◽  
Hana A Itani ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Organ Damage ◽  
Matrix Proteins ◽  
Locked Nucleic Acid ◽  
Ang Ii ◽  
End Organ Damage ◽  
Acid Inhibitor ◽  
Vascular Stiffening ◽  
Aortic Stiffening

We and others have shown that hypertension (HTN) is associated with a striking deposition of collagen in the vascular adventitia. This causes vascular stiffening, which increases pulse wave velocity and contributes to end-organ damage. Through a screen of vascular microRNAs (miRNAs), we found that miR-762 is the most upregulated miRNA in mice with angiotensin II (Ang II)-induced HTN. qRT-PCR confirmed that miR-762 is upregulated 6.35±1.22 (p=0.03) fold in aortas of Ang II-infused mice compared with controls. This was a direct effect of Ang II, as miR-762 upregulation was not eliminated by lowering blood pressure with hydralazine and hydrochlorothiazide and was increased only 2-fold in DOCA salt HTN. To study the role of miR-762 in HTN, we administered a locked nucleic acid inhibitor of miR-762 (antagomiR-762). AntagomiR-762 administration did not alter the hypertensive response to Ang II, yet it normalized stress-strain relationships and aortic energy storage that occurs in systole (Table). Further studies showed that antagomiR-762 dramatically affected vascular matrix proteins, reducing mRNA for several collagens and fibronectin and dramatically upregulating collagenases MMP1a, 8 and 13 (Table). Thus, miR-762 has a major role in modulating vascular stiffening and its inhibition dramatically inhibits pathological fibrosis, enhances matrix degradation and normalizes aortic stiffness. AntagomiR-762 might represent a new approach to prevent aortic stiffening and its consequent end-organ damage.

Oxidative stress and endothelial dysfunction

2007 ◽  
Vol 27 (01) ◽  
pp. 5-12 ◽  
Author(s):  
G. Muller ◽  
C. Goettsch ◽  
H. Morawietz
Keyword(s):  
Oxidative Stress ◽  
Endothelial Dysfunction ◽  
Vascular Function ◽  
Vessel Wall ◽  
Clinical Implications ◽  
Oxygen Species ◽  
Vascular Oxidative Stress ◽  
Arteries And Veins ◽  
Different Sources

SummaryThis review focuses on the role of vascular oxidative stress in the development and progression of endothelial dysfunction. We discuss different sources of oxidative stress in the vessel wall, oxidative stress and coagulation, the role of oxidative stress and vascular function in arteries and veins, the flow-dependent regulation of reactive oxygen species, the putative impact of oxidative stress on atherosclerosis, the interaction of angiotensin II, oxidative stress and endothelial dysfunction, and clinical implications.

Association of mitochondrial SOD deficiency with salt-sensitive hypertension and accelerated renal senescence

2007 ◽  
Vol 102 (1) ◽  
pp. 255-260 ◽  
Author(s):  
Bernardo Rodriguez-Iturbe ◽  
Lili Sepassi ◽  
Yasmir Quiroz ◽  
Zhenmin Ni ◽  
Nosratola D. Vaziri
Keyword(s):  
Oxidative Stress ◽  
Glomerular Sclerosis ◽  
Tubular Damage ◽  
Wild Type ◽  
Mitochondrial Superoxide ◽  
Show Evidence ◽  
Blood Pressures ◽  
Renal Senescence ◽  
Salt Sensitive Hypertension

Mitochondria are the major source of superoxide (O2−) in the aerobic organisms. O2− produced by the mitochondria is converted to hydrogen peroxide by mitochondrial superoxide dismutase (SOD2). Mice with complete SOD2 deficiency (SOD2−/−) exhibit dilated cardiomyopathy and fatty liver leading to neonatal mortality, whereas mice with partial SOD2 deficiency (SOD2+/−) show evidence of O2−-induced mitochondrial damage resembling cell senescence. Since earlier studies have provided compelling evidence for the role of oxidative stress and tubulointerstitial inflammation in the pathogenesis of hypertension, we tested the hypothesis that partial SOD2 deficiency may result in hypertension. Wild-type (SOD2+/+) and partial SOD2-deficient (SOD2+/−) mice had similar blood pressures at 6–7 mo of age, but at 2 yr SOD2+/− mice had higher blood pressure. Oxidative stress, renal interstitial T-cell and macrophage infiltration, tubular damage, and glomerular sclerosis were all significantly increased in 2-yr-old SOD2+/− mice. High-salt diet induced hypertension in 6-mo-old SOD2-deficient mice but not in wild-type mice. In conclusion, partial SOD2 deficiency results in oxidative stress and renal interstitial inflammation, changes compatible with accelerated renal senescence and salt-sensitive hypertension. These findings are consistent with the pattern described in numerous other models of salt-sensitive hypertension and resemble that commonly seen in elderly humans.

scholarly journals Interaction of TNF‐α with Angiotensin II contributes to mitochondrial oxidative stress and end organ damage in rats

2008 ◽  
Vol 22 (S1) ◽  
Author(s):  
Nithya Mariappan ◽  
Carrie Elks ◽  
Kayla Prejean ◽  
Srinivas Sriramula ◽  
Joseph Francis
Keyword(s):  
Oxidative Stress ◽  
Angiotensin Ii ◽  
Organ Damage ◽  
Mitochondrial Oxidative Stress ◽  
End Organ Damage ◽  
Tnf Α

Abstract 1756: Angiotensin II Induced End Organ Damage is Attenuated in Mice Lacking the Gene for TNF: A Mitochondrial Perspective

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Nithya Mariappan ◽  
Srinivas Sriramula ◽  
Joseph Francis
Keyword(s):  
Oxidative Stress ◽  
Blood Pressure ◽  
Angiotensin Ii ◽  
Organ Damage ◽  
Left Ventricular ◽  
Lv Function ◽  
Resonance Spectroscopy ◽  
Cardiac Damage ◽  
Atp Production ◽  
End Organ Damage

Recent findings from our lab and others suggest that the renin-angiotensin system and cytokine interaction contribute to the pathophysiology of cardiovascular disease. In this study, we determined the role played by tumor necrosis factor (TNF) in angiotensin II (ANGII) induced end organ damage at the mitochondrial level. Method : Wild type (WT) and TNF knockout (TNF (−/−)) mice were implanted with osmotic minipumps containing ANG II (1 μg/kg/min) or saline for 14 days. Blood pressure was recorded using telemetry. At the end of the study, left ventricular (LV) function was measured using echocardiography. Mice were sacrificed and the LV was removed and mitochondria isolated for oxidative stress measurement using Electron paramagnetic resonance spectroscopy. Structural integrity of mitochondria was assessed by electron microscopy (EM) and function by measuring mitochondrial redox status. Results: (see table ) ANGII infusion in WT mice resulted in a significant increase in blood pressure and was accompanied by a decrease in fractional shortening. These animals also had increased levels of superoxide and ROS in the LV tissues. The mitochondrial integrity of the cardiomyocytes was damaged both in the isolated mitochondria and tissue as evidenced by EM studies. Mitochondrial superoxide and total ROS were increased and this was accompanied by a decrease in complex activity and reduced ATP production. In contrast, ANGII infusion in TNF (−/−) attenuated cardiac damage, mitochondrial oxidative stress and restored ATP production. Conclusion: ANGII induced cardiac damage is mediated by TNF. These data also demonstrate that ANGII induced increase in TNF inhibits mitochondrial function by affecting electron transport chain activity and indirectly through an increase in oxygen free radicals thereby decreasing ATP synthesis and contributing to end organ damage in hypertension.

scholarly journals Role of p47 phox in Vascular Oxidative Stress and Hypertension Caused by Angiotensin II

Hypertension ◽  
2002 ◽  
Vol 40 (4) ◽  
pp. 511-515 ◽  
Author(s):  
Ulf Landmesser ◽  
Hua Cai ◽  
Sergey Dikalov ◽  
Louise McCann ◽  
Jinah Hwang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Angiotensin Ii ◽  
Vascular Oxidative Stress

Abstract 071: Cytokine-angiotensin II Interplay in Cyclophilin D-mediated Vascular Oxidative Stress and Hypertension

Hypertension ◽  
2014 ◽  
Vol 64 (suppl_1) ◽  
Author(s):  
Rafal Nazarewicz ◽  
Anna Dikalova ◽  
Hana Itani ◽  
William McMaster ◽  
Alfiya Bikineyeva ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Blood Pressure ◽  
Angiotensin Ii ◽  
Complex I ◽  
Isometric Tension ◽  
Regulatory Subunit ◽  
Cyclophilin D ◽  
Sanglifehrin A

Vascular inflammation and oxidative stress interact in a feed-forward fashion to promote vascular disease and hypertension. We hypothesized that angiotensin II and inflammatory cytokines encountered in hypertension co-operatively induce superoxide (O 2 • - ) production by mitochondrial complex I and that efforts to reduce complex I O 2 • - will reduce hypertension. Treatment of human aortic endothelial cells in culture with angiotensin II (10 nM), IL17A (10 nM) and TNFα (1 nM), factors known to contribute to the hypertensive milieu, co-operatively induced mitochondrial O 2 • - from 340 to 958 pmol/mg protein as measured by HPLC and MitoSOX. This response was abolished by the complex I inhibitor rotenone. We further tested a potential role of Cyclophilin D (CypD), the redox sensitive regulatory subunit of the mitochondrial transition pore in complex I O 2 • - production. Both the specific CypD inhibitor Sanglifehrin A and knockdown of CypD by siRNA prevented endothelial cell O 2 • - production in response to Ang/IL17/TNF. We also found that this cytokine-angiotensin II milieu induced S-glutathionylation of CypD and that scavenging mitochondrial H 2 O 2 with mitoEbselen prevents this and eliminates CypD dependent complex I O 2 • - production. We further studied the functional role of oxidative stress induced by Ang/IL17/TNF in isometric tension studies of mouse aortic rings. Twenty-four hour treatment of organoid cultured vessels with AngII/IL17/TNF reduced endothelium-dependent vasodilatation to acetylcholine and this was prevented by knockdown of CypD and was not observed in vessels of mice with overexpression of mitochondrial SOD or mitochondrial catalase. The in vivo role of CypD in regulation of vascular O 2 • - and blood pressure was further studied in mice infused with angiotensin II (490 ng/kg/min). Treatment with Sanglifehrin A after the onset of hypertension reduced blood pressure from 162 to 133 mmHg (P<0.01), reduced vascular O 2 • - and improved endothelium-dependent vasodilation. These studies have defined a novel role of Cyclophilin D as a cause of vascular dysfunction and hypertension and have provided a new target for treatment of this disease.

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