Inflammation in Hypertension

For more than 50 years, evidence has accumulated that inflammation contributes to the pathogenesis of hypertension. Immune cells have been observed in vessels and kidneys of hypertensive humans. Biomarkers of inflammation, including high sensitivity C-reactive protein, various cytokines, and products of the complement pathway are elevated in humans with hypertension. Emerging evidence suggests that hypertension is accompanied and indeed initiated by activation of complement, the inflammasome, and by a change in the phenotype of circulating immune cells, particularly myeloid cells. High-dimensional transcriptomic analyses are providing insight into new subclasses of immune cells that are likely injurious in hypertension. These inflammatory events are interdependent and there is ultimately engagement of the adaptive immune system through mechanisms involving oxidative stress, modification of endogenous proteins, and alterations in antigen processing and presentation. These observations suggest new therapeutic opportunities to reduce end organ damage in hypertension might be used and guided by levels of inflammatory biomarkers.

Sympathetic Enhancement of Memory T-Cell Homing and Hypertension Sensitization

RATIONALE

Effector memory T lymphocytes (T_EM cells) exacerbate hypertension in response to repeated hypertensive stimuli. These cells reside in the bone marrow for prolonged periods and can be reactivated on reexposure to the hypertensive stimulus.

OBJECTIVE

Because hypertension is associated with increased sympathetic outflow to the bone marrow, we hypothesized that sympathetic nerves regulate accumulation and reactivation of bone marrow-residing hypertension-specific T_EM cells.

METHODS AND RESULTS

Using unilateral superior cervical ganglionectomy in wild-type C57BL/6 mice, we showed that sympathetic nerves create a bone marrow environment that supports residence of hypertension-specific CD8⁺ T cells. These cells, defined by their proliferative response on coculture with dendritic cells from Ang (angiotensin) II-infused mice, were reduced in denervated compared with innervated bone of Ang II-infused mice. Adoptively transferred CD8⁺ T cells from Ang II-infused mice preferentially homed to innervated compared with denervated bone. In contrast, ovalbumin responsive T cells from OT-I mice did not exhibit this preferential homing. Increasing superior cervical ganglion activity by activating Gq-coupled designer receptor exclusively activated by designer drug augmented CD8⁺ T_EM bone marrow accumulation. Adoptive transfer studies using mice lacking β2AR (β2 adrenergic receptors) indicate that β2AR in the bone marrow niche, rather than T-cell β2AR is critical for T_EM cell homing. Inhibition of global sympathetic outflow using Gi-coupled DREADD (designer receptor exclusively activated by designer drug) injected into the rostral ventrolateral medulla or treatment with a β2AR antagonist reduced hypertension-specific CD8⁺ T_EM cells in the bone marrow and reduced the hypertensive response to a subsequent response to low dose Ang II.

CONCLUSIONS

Sympathetic nerves contribute to the homing and survival of hypertension-specific T_EM cells in the bone marrow after they are formed in hypertension. Inhibition of sympathetic nerve activity and β2AR blockade reduces these cells and prevents the blood pressure elevation and renal inflammation on reexposure to hypertension stimuli.

Effects of Interleukin-1β Inhibition on Blood Pressure, Incident Hypertension, and Residual Inflammatory Risk: A Secondary Analysis of CANTOS

Supplemental Digital Content is available in the text.

While hypertension and inflammation are physiologically inter-related, the effect of therapies that specifically target inflammation on blood pressure is uncertain. The recent CANTOS (Canakinumab Anti-inflammatory Thrombosis Outcomes Study) afforded the opportunity to test whether IL (interleukin)-1β inhibition would reduce blood pressure, prevent incident hypertension, and modify relationships between hypertension and cardiovascular events. CANTOS randomized 10 061 patients with prior myocardial infarction and hsCRP (high sensitivity C-reactive protein) ≥2 mg/L to canakinumab 50 mg, 150 mg, 300 mg, or placebo. A total of 9549 trial participants had blood pressure recordings during follow-up; of these, 80% had a preexisting diagnosis of hypertension. In patients without baseline hypertension, rates of incident hypertension were 23.4, 26.6, and 28.1 per 100-person years for the lowest to highest baseline tertiles of hsCRP (P>0.2). In all participants random allocation to canakinumab did not reduce blood pressure (P>0.2) or incident hypertension during the follow-up period (hazard ratio, 0.96 [0.85–1.08], P>0.2). IL-1β inhibition with canakinumab reduces major adverse cardiovascular event rates. These analyses suggest that the mechanisms underlying this benefit are not related to changes in blood pressure or incident hypertension.

Mitochondrial Deacetylase Sirt3 Reduces Vascular Dysfunction and Hypertension While Sirt3 Depletion in Essential Hypertension Is Linked to Vascular Inflammation and Oxidative Stress

RATIONALE

Hypertension represents a major risk factor for stroke, myocardial infarction, and heart failure and affects 30% of the adult population. Mitochondrial dysfunction contributes to hypertension, but specific mechanisms are unclear. The mitochondrial deacetylase Sirt3 (Sirtuin 3) is critical in the regulation of metabolic and antioxidant functions which are associated with hypertension, and cardiovascular disease risk factors diminish Sirt3 level.

OBJECTIVE

We hypothesized that reduced Sirt3 expression contributes to vascular dysfunction in hypertension, but increased Sirt3 protects vascular function and decreases hypertension.

METHODS AND RESULTS

To test the therapeutic potential of targeting Sirt3 expression, we developed new transgenic mice with global Sirt3OX (Sirt3 overexpression), which protects from endothelial dysfunction, vascular oxidative stress, and hypertrophy and attenuates Ang II (angiotensin II) and deoxycorticosterone acetate-salt induced hypertension. Global Sirt3 depletion in Sirt3^-/- mice results in oxidative stress due to hyperacetylation of mitochondrial superoxide dismutase (SOD2), increases HIF1α (hypoxia-inducible factor-1), reduces endothelial cadherin, stimulates vascular hypertrophy, increases vascular permeability and vascular inflammation (p65, caspase 1, VCAM [vascular cell adhesion molecule-1], ICAM [intercellular adhesion molecule-1], and MCP1 [monocyte chemoattractant protein 1]), increases inflammatory cell infiltration in the kidney, reduces telomerase expression, and accelerates vascular senescence and age-dependent hypertension; conversely, increased Sirt3 expression in Sirt3OX mice prevents these deleterious effects. The clinical relevance of Sirt3 depletion was confirmed in arterioles from human mediastinal fat in patients with essential hypertension showing a 40% decrease in vascular Sirt3, coupled with Sirt3-dependent 3-fold increases in SOD2 acetylation, NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) activity, VCAM, ICAM, and MCP1 levels in hypertensive subjects compared with normotensive subjects.

CONCLUSIONS

We suggest that Sirt3 depletion in hypertension promotes endothelial dysfunction, vascular hypertrophy, vascular inflammation, and end-organ damage. Our data support a therapeutic potential of targeting Sirt3 expression in vascular dysfunction and hypertension.

Central EP3 (E Prostanoid 3) Receptors Mediate Salt-Sensitive Hypertension and Immune Activation

We recently identified a pathway underlying immune activation in hypertension. Proteins oxidatively modified by reactive isoLG (isolevuglandin) accumulate in dendritic cells (DCs). PGE₂ (Prostaglandin E2) has been implicated in the inflammation associated with hypertension. We hypothesized that PGE₂ via its EP (E prostanoid) 3 receptor contributes to DC activation in hypertension. EP3^-/- mice and wild-type littermates were exposed to sequential hypertensive stimuli involving an initial 2-week exposure to the nitric oxide synthase inhibitor N^ω-nitro-L-arginine methyl ester hydrochloride in drinking water, followed by a 2-week washout period, and a subsequent 4% high-salt diet for 3 weeks. In wild-type mice, this protocol increased systolic pressure from 123±2 to 148±8 mm Hg (P<0.05). This was associated with marked renal inflammation and a striking accumulation of isoLG adducts in splenic DCs. However, the increases in blood pressure, renal T-cell infiltration, and DC isoLG formation were completely prevented in EP3^-/- mice. Similar protective effects were also observed in wild-type mice that received intracerebroventricular injection of a lentiviral vector encoding shRNA targeting the EP3 receptor. Further, in vitro experiments indicated that PGE₂ also acts directly on DCs via its EP1 receptors to stimulate intracellular isoLG formation. Together, these findings provide new insight into how EP receptors in both the central nervous system and peripherally on DCs promote inflammation in salt-induced hypertension.

Isolevuglandins as mediators of disease and the development of dicarbonyl scavengers as pharmaceutical interventions

Products of lipid peroxidation include a number of reactive lipid aldehydes such as malondialdehyde, 4-hydroxy-nonenal, 4-oxo-nonenal, and isolevuglandins (IsoLGs). Although these all contribute to disease processes, the most reactive are the IsoLGs, which rapidly adduct to lysine and other cellular primary amines, leading to changes in protein function, cross-linking and immunogenicity. Their rapid reactivity means that only IsoLG adducts, and not the unreacted aldehyde, can be readily measured. This high reactivity also makes it challenging for standard cellular defense mechanisms such as aldehyde reductases and oxidases to dispose of them before they react with proteins and other cellular amines. This led us to seek small molecule primary amines that might trap and inactivate IsoLGs before they could modify cellular proteins or other endogenous cellular amines such as phosphatidylethanolamines to cause disease. Our studies identified 2-aminomethylphenols including 2-hydroxybenzylamine as IsoLG scavengers. Subsequent studies showed that they also trap other lipid dicarbonyls that react with primary amines such as 4-oxo-nonenal and malondialdehyde, but not hydroxyalkenals like 4-hydroxy-nonenal that preferentially react with soft nucleophiles. This review describes the use of these 2-aminomethylphenols as dicarbonyl scavengers to assess the contribution of IsoLGs and other amine-reactive lipid dicarbonyls to disease and as therapeutic agents.

Abstract P3018: Sirt3 Depletion in Human Essential Hypertension is Linked to Vascular Inflammation and Oxidative Stress While Endothelial Specific Sirt3 Depletion in Mice Promotes Vascular Dysfunction and Increases Hypertension

Hypertension represents a major risk factor for stroke, myocardial infarction, and heart failure and affects 30% of adult population. Vascular dysfunction is crucial in hypertension pathophysiology and exhibits bidirectional relationship. Metabolic disorders and oxidative stress contribute to vascular dysfunction, and mitochondrial deacetylase Sirt3 is critical in the regulation of metabolic and antioxidant functions. We hypothesized that reduced Sirt3 expression contributes to vascular dysfunction and essential hypertension. We studied Sirt3 in arterioles from human mediastinal fat in patients with essential hypertension compared with normotensive subjects. Pathophysiological role of vascular Sirt3 depletion was studied in mice with tamoxifen-inducible endothelial specific Sirt3 depletion (Ec Sirt3KO ). For the first time, we showed a 40% decrease in vascular Sirt3 level and 400% increase in SOD2 acetylation in hypertensive subjects which was linked to increased oxidative stress measured by superoxide overproduction and vascular inflammation due to elevated NfKB activity, VCAM, ICAM and MCP-1 levels. Interestingly, global Sirt3 depletion in mice increases blood pressure, inactivates key mitochondrial antioxidant SOD2 due to acetylation, increases vascular p65, VCAM, ICAM and MCP1, and increased T cell infiltration in kidney, induces cell-senescence and promotes vascular aging while global Sirt3 overexpression prevents these deleterious effects. We tested if Ec Sirt3KO mice have vascular dysfunction and hypertension. Both basal and angiotensin II-induced blood pressure was increased in Ec Sirt3KO mice accompanied by endothelial dysfunction and vascular O 2 • overproduction. Treatment of Ec Sirt3KO mice with SOD2-mimetic mitoTEMPO reduced vascular inflammation, markers of cell-senescence and vascular aging to the wild-type control levels while treatment of Ang II-infused Ec Sirt3KO mice partially rescues from vascular inflammation and attenuates accelerated vascular aging. We suggest that Sirt3 depletion in hypertension promotes both endothelial oxidative stress and metabolic dysfunction. Our data support a therapeutic potential of targeting Sirt3 expression in vascular dysfunction and hypertension.

High Salt Activates CD11c+ Antigen-Presenting Cells via SGK (Serum Glucocorticoid Kinase) 1 to Promote Renal Inflammation and Salt-Sensitive Hypertension

Salt-sensing mechanisms in hypertension involving the kidney, vasculature, and central nervous system have been well studied; however, recent studies suggest that immune cells can sense sodium (Na+). Antigen-presenting cells (APCs) including dendritic cells critically modulate inflammation by activating T cells and producing cytokines. We recently found that Na+ enters dendritic cells through amiloride-sensitive channels including the α and γ subunits of the epithelial sodium channel (ENaC) and mediates nicotinamide adenine dinucleotide phosphate oxidase-dependent formation of immunogenic IsoLG (isolevuglandin)-protein adducts leading to inflammation and hypertension. Here, we describe a novel pathway in which the salt-sensing kinase SGK1 (serum/glucocorticoid kinase 1) in APCs mediates salt-induced expression and assembly of ENaC-α and ENaC-γ and promotes salt-sensitive hypertension by activation of the nicotinamide adenine dinucleotide phosphate oxidase and formation of IsoLG-protein adducts. Mice lacking SGK1 in CD11c+ cells were protected from renal inflammation, endothelial dysfunction, and developed blunted hypertension during the high salt feeding phase of the N-Nitro-L-arginine methyl ester hydrochloride/high salt model of salt-sensitive hypertension. CD11c+ APCs treated with high salt exhibited increased expression of ENaC-γ which coimmunoprecipitated with ENaC-α. This was associated with increased activation and expression of various nicotinamide adenine dinucleotide phosphate oxidase subunits. Genetic deletion or pharmacological inhibition of SGK1 in CD11c+ cells prevented the high salt-induced expression of ENaC and nicotinamide adenine dinucleotide phosphate oxidase. These studies indicate that expression of SGK1 in CD11c+ APCs contributes to the pathogenesis of salt-sensitive hypertension.

Abstract 112: Endogenous-Antigen-Specific T Cell Receptor Activation of CD4+ T Cells in the Heart is Required for Maladaptive Cardiac Remodeling Due to Pressure Overload

Cardiac pressure overload is associated with an adaptive immune response that drives maladaptive cardiac remodeling. CD4+ T cells are activated and expanded specifically in the heart-draining mediastinal lymph nodes (mLNs) and infiltrate the left ventricle (LV) in response to transverse aortic constriction (TAC). However, the specific mechanisms triggering T cell activation during the progression of TAC-induced HF remain unknown. We hypothesized that T cell receptor (TCR)-dependent activation of CD4+ T cells by endogenous antigens initiates and sustains maladaptive cardiac remodeling during the progression of TAC induced HF. We evaluated TCR mediated CD4+ T cell activation in the LV of Nur77 GFP mice, which transiently express GFP exclusively upon TCR stimulation. Strikingly, we found LV-infiltrated GFP + CD4+ T cells that increased in number as maladaptive remodeling and cardiac dysfunction progressed in response to TAC. Next generation sequencing of LV-sorted GFP + CD4+ T cells after 8 weeks of TAC revealed a limited repertoire of TCR clones relative to the periphery, demonstrating a restricted CD4+ T cell response to endogenous antigens. We further assessed the requirement for endogenous antigens by immunizing OT-II transgenic mice, which exclusively express a TCR specific for exogenous chicken ovalbumin (OVA), with OVA in the onset of TAC. While OVA induced CD4+ T cell activation and infiltration into the LV, this was not sufficient to induce cardiac dysfunction, demonstrating the importance of an endogenous antigen-specific response. Reactive isolevuglandins (IsoLGs) are formed during oxidative stress, and rapidly adduct to self-proteins forming endogenous neoantigens that elicit CD4+ T cell activation. We treated mice with the IsoLG scavenger 2-hydroxybenzylamine (2-HOBA) in the onset of TAC, which significantly reduced accumulation of IsoLG-protein adducts in dendritic cells, prevented CD4+ T cell activation in the mLNs, and prevented cardiac dysfunction. Thus, our results demonstrate that CD4+ T cell recognition of endogenous antigens in the LV, including IsoLG-protein adducts, via the TCR is required for maladaptive cardiac remodeling and cardiac dysfunction in pressure overload-induced HF.

NOX5 as a therapeutic target in cerebral ischemic injury

In this issue of the JCI, Casas et al. define a previously unknown role of the NADPH oxidase catalytic subunit NOX5 in cerebral infarction. Using a mouse expressing human NOX5 in the endothelium, the investigators show that NOX5 is activated and plays a deleterious role in promoting edema, infarction, and ultimately, worsened neurological function following cerebral ischemia. They provide evidence that this is due to the breakdown of the blood-brain barrier (BBB) and that a unique pharmacological inhibitor of NOX5, ML090, if given early, around the time of reoxygenation, can maintain BBB integrity. Future studies of NOX5 inhibition in humans, particularly in the setting of thrombolysis, are warranted.

Tobacco smoking induces cardiovascular mitochondrial oxidative stress, promotes endothelial dysfunction, and enhances hypertension

Tobacco smoking is a major risk factor for cardiovascular disease and hypertension. It is associated with the oxidative stress and induces metabolic reprogramming, altering mitochondrial function. We hypothesized that cigarette smoke induces cardiovascular mitochondrial oxidative stress, which contributes to endothelial dysfunction and hypertension. To test this hypothesis, we studied whether the scavenging of mitochondrial H₂O₂ in transgenic mice expressing mitochondria-targeted catalase (mCAT) attenuates the development of cigarette smoke/angiotensin II-induced mitochondrial oxidative stress and hypertension compared with wild-type mice. Two weeks of exposure of wild-type mice with cigarette smoke increased systolic blood pressure by 17 mmHg, which was similar to the effect of a subpresssor dose of angiotensin II (0.2 mg·kg^-1·day^-1), leading to a moderate increase to the prehypertensive level. Cigarette smoke exposure and a low dose of angiotensin II cooperatively induced severe hypertension in wild-type mice, but the scavenging of mitochondrial H₂O₂ in mCAT mice completely prevented the development of hypertension. Cigarette smoke and angiotensin II cooperatively induced oxidation of cardiolipin (a specific biomarker of mitochondrial oxidative stress) in wild-type mice, which was abolished in mCAT mice. Cigarette smoke and angiotensin II impaired endothelium-dependent relaxation and induced superoxide overproduction, which was diminished in mCAT mice. To mimic the tobacco smoke exposure, we used cigarette smoke condensate, which induced mitochondrial superoxide overproduction and reduced endothelial nitric oxide (a hallmark of endothelial dysfunction in hypertension). Western blot experiments indicated that tobacco smoke and angiotensin II reduce the mitochondrial deacetylase sirtuin-3 level and cause hyperacetylation of a key mitochondrial antioxidant, SOD2, which promotes mitochondrial oxidative stress. NEW & NOTEWORTHY This work demonstrates tobacco smoking-induced mitochondrial oxidative stress, which contributes to endothelial dysfunction and development of hypertension. We suggest that the targeting of mitochondrial oxidative stress can be beneficial for treatment of pathological conditions associated with tobacco smoking, such as endothelial dysfunction, hypertension, and cardiovascular diseases.

Th1-type immune responses to Porphyromonas gingivalis antigens exacerbate angiotensin II-dependent hypertension and vascular dysfunction

Background and Purpose

Emerging evidence indicates that hypertension is mediated by immune mechanisms. We hypothesized that exposure to Porphyromonas gingivalis antigens, commonly encountered in periodontal disease, can enhance immune activation in hypertension and exacerbate the elevation in BP, vascular inflammation and vascular dysfunction.

Experimental Approach

Th1 immune responses were elicited through immunizations using P. gingivalis lysate antigens (10 μg) conjugated with aluminium oxide (50 μg) and IL‐12 (1 μg). The hypertension and vascular endothelial dysfunction evoked by subpressor doses of angiotensin II (0.25 mg·kg⁻¹·day⁻¹) were studied, and vascular inflammation was quantified by flow cytometry and real‐time PCR.

Key Results

Systemic T‐cell activation, a characteristic of hypertension, was exacerbated by P. gingivalis antigen stimulation. This translated into increased aortic vascular inflammation with enhanced leukocyte, in particular, T‐cell and macrophage infiltration. The expression of the Th1 cytokines, IFN‐γ and TNF‐α, and the transcription factor, TBX21, was increased in aortas of P. gingivalis/IL‐12/aluminium oxide‐immunized mice, while IL‐4 and TGF‐β were unchanged. These immune changes in mice with induced T‐helper‐type 1 immune responses were associated with an enhanced elevation of BP and endothelial dysfunction compared with control mice in response to 2 week infusion of a subpressor dose of angiotensin II.

Conclusions and Implications

These results support the concept that Th1 immune responses induced by bacterial antigens such as P. gingivalis can increase sensitivity to subpressor pro‐hypertensive insults such as low‐dose angiotensin II, thus providing a mechanistic link between chronic infection, such as periodontitis, and hypertension.

Linked Articles

This article is part of a themed section on Immune Targets in Hypertension. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.12/issuetoc

Glucose metabolism controls disease-specific signatures of macrophage effector functions

BACKGROUND

In inflammatory blood vessel diseases, macrophages represent a key component of the vascular infiltrates and are responsible for tissue injury and wall remodeling.

METHODS

To examine whether inflammatory macrophages in the vessel wall display a single distinctive effector program, we compared functional profiles in patients with either coronary artery disease (CAD) or giant cell arteritis (GCA).

RESULTS

Unexpectedly, monocyte-derived macrophages from the 2 patient cohorts displayed disease-specific signatures and differed fundamentally in metabolic fitness. Macrophages from CAD patients were high producers for T cell chemoattractants (CXCL9, CXCL10), the cytokines IL-1β and IL-6, and the immunoinhibitory ligand PD-L1. In contrast, macrophages from GCA patients upregulated production of T cell chemoattractants (CXCL9, CXCL10) but not IL-1β and IL-6, and were distinctly low for PD-L1 expression. Notably, disease-specific effector profiles were already identifiable in circulating monocytes. The chemokinehicytokinehiPD-L1hi signature in CAD macrophages was sustained by excess uptake and breakdown of glucose, placing metabolic control upstream of inflammatory function.

CONCLUSIONS

We conclude that monocytes and macrophages contribute to vascular inflammation in a disease-specific and discernible pattern, have choices to commit to different functional trajectories, are dependent on glucose availability in their immediate microenvironment, and possess memory in their lineage commitment.

FUNDING

Supported by the NIH (R01 AR042527, R01 HL117913, R01 AI108906, P01 HL129941, R01 AI108891, R01 AG045779 U19 AI057266, R01 AI129191), I01 BX001669, and the Cahill Discovery Fund.

Abstract 060: Mitochondrial Deacetylase Sirt3 in Endothelial and Smooth Muscle Cells Protects From Vascular Dysfunction and Attenuates Hypertension

Vascular dysfunction plays a key role in the development of hypertension and heart disease which causes one-third of deaths worldwide. Cardiovascular disease risk factors reduce mitochondrial deacetylase Sirt3 and Sirt3 declines with age paralleling the increased incidence of cardiovascular disease and hypertension; however, the role of Sirt3 was largely ignored. We hypothesized that Sirt3 plays critical role in vascular dysfunction and hypertension. To test this hypothesis we have developed novel tamoxifen-inducible endothelium specific Sirt3 knockout (Ec Sirt3KO ), endothelial Sirt3 overexpressing (Ec Sirt3OX ), smooth muscle Sirt3 knockout (Smc Sirt3KO ), smooth muscle Sirt3 overexpressing (Smc Sirt3OX ) and global Sirt3 overexpressing (Sirt3OX) mice on C57Bl/6J background, and examined the effect of Sirt3 expression on vascular dysfunction and angiotensin II-induced hypertension. It was found that cell-specific Sirt3 depletion in endothelial and smooth muscle in Ec Sirt3KO and Smc Sirt3KO mice increases vascular permeability by 2-fold, raises T cell and monocyte vascular accumulation, diminishes endothelial NO and increases blood pressure by 10 mm Hg compared with wild-type Sham mice. Angiotensin II infusion in Ec Sirt3KO and Smc Sirt3KO mice caused vascular hyperpermeability, increased vascular hypertrophy, exacerbated endothelial dysfunction and hypertension. Meanwhile, Sirt3 overexpression reduced vascular permeability and diminished vascular inflammation compared to Sham wild-type mice. Sirt3 overexpression in endothelial and smooth muscle prevents angiotensin II-induced vascular hyperpermeability, inhibits vascular oxidative stress, preserves endothelial-dependent relaxation, diminishes vascular hypertrophy and attenuates hypertension by 20 mm Hg in angiotensin II-infused Ec Sirt3OX and Smc Sirt3OX mice compared with the wild-type littermates. Interestingly, Sirt3 depletion in human aortic endothelial cells and human vascular smooth muscle cells reduces expression of differentiation markers. We suggest that Sirt3 is central in redox and metabolic regulations of smooth muscle and endothelial cells. Our data support a therapeutic potential of targeting Sirt3 in vascular dysfunction and hypertension.