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1.
Int J Mol Sci ; 22(16)2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34445519

RESUMO

Cardiovascular disease is the leading cause of morbidity and mortality in diabetes. Recent clinical studies indicate that sodium-glucose co-transporter 2 (SGLT2) inhibitors improve cardiovascular outcomes in patients with diabetes. The mechanism underlying the beneficial effect of SGLT2 inhibitors is not completely clear but may involve direct actions on vascular cells. SGLT2 inhibitors increase the bioavailability of endothelium-derived nitric oxide and thereby restore endothelium-dependent vasodilation in diabetes. In addition, SGLT2 inhibitors favorably regulate the proliferation, migration, differentiation, survival, and senescence of endothelial cells (ECs). Moreover, they exert potent antioxidant and anti-inflammatory effects in ECs. SGLT2 inhibitors also inhibit the contraction of vascular smooth muscle cells and block the proliferation and migration of these cells. Furthermore, studies demonstrate that SGLT2 inhibitors prevent postangioplasty restenosis, maladaptive remodeling of the vasculature in pulmonary arterial hypertension, the formation of abdominal aortic aneurysms, and the acceleration of arterial stiffness in diabetes. However, the role of SGLT2 in mediating the vascular actions of these drugs remains to be established as important off-target effects of SGLT2 inhibitors have been identified. Future studies distinguishing drug- versus class-specific effects may optimize the selection of specific SGLT2 inhibitors in patients with distinct cardiovascular pathologies.


Assuntos
Complicações do Diabetes/prevenção & controle , Inibidores do Transportador 2 de Sódio-Glicose/farmacologia , Remodelação Vascular/efeitos dos fármacos , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Antioxidantes/farmacologia , Antioxidantes/uso terapêutico , Complicações do Diabetes/metabolismo , Células Endoteliais/citologia , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Humanos , Óxido Nítrico/metabolismo , Inibidores do Transportador 2 de Sódio-Glicose/uso terapêutico
2.
Antioxidants (Basel) ; 9(9)2020 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-32899732

RESUMO

Heme oxygenase-1 (HO-1) catalyzes the degradation of heme into carbon monoxide (CO), iron, and biliverdin, which is rapidly metabolized to bilirubin. The activation of vascular smooth muscle cells (SMCs) plays a critical role in mediating the aberrant arterial response to injury and a number of vascular diseases. Pharmacological induction or gene transfer of HO-1 improves arterial remodeling in animal models of post-angioplasty restenosis, vascular access failure, atherosclerosis, transplant arteriosclerosis, vein grafting, and pulmonary arterial hypertension, whereas genetic loss of HO-1 exacerbates the remodeling response. The vasoprotection evoked by HO-1 is largely ascribed to the generation of CO and/or the bile pigments, biliverdin and bilirubin, which exert potent antioxidant and anti-inflammatory effects. In addition, these molecules inhibit vascular SMC proliferation, migration, apoptosis, and phenotypic switching. Several therapeutic strategies are currently being pursued that may allow for the targeting of HO-1 in arterial remodeling in various pathologies, including the use of gene delivery approaches, the development of novel inducers of the enzyme, and the administration of unique formulations of CO and bilirubin.

3.
Adv Exp Med Biol ; 1265: 39-56, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32761569

RESUMO

Cardiovascular disease is the major cause of global mortality and disability. Abundant evidence indicates that amino acids play a fundamental role in cardiovascular physiology and pathology. Decades of research established the importance of L-arginine in promoting vascular health through the generation of the gas nitric oxide. More recently, L-glutamine, L-tryptophan, and L-cysteine have also been shown to modulate vascular function via the formation of a myriad of metabolites, including a number of gases (ammonia, carbon monoxide, hydrogen sulfide, and sulfur dioxide). These amino acids and their metabolites preserve vascular homeostasis by regulating critical cellular processes including proliferation, migration, differentiation, apoptosis, contractility, and senescence. Furthermore, they exert potent anti-inflammatory and antioxidant effects in the circulation, and block the accumulation of lipids within the arterial wall. They also mitigate known risk factors for cardiovascular disease, including hypertension, hyperlipidemia, obesity, and diabetes. However, in some instances, the metabolism of these amino acids through discrete pathways yields compounds that fosters vascular disease. While supplementation with amino acid monotherapy targeting the deficiency has ameliorated arterial disease in many animal models, this approach has been less successful in the clinic. A more robust approach combining amino acid supplementation with antioxidants, anti-inflammatory agents, and/or specific amino acid enzymatic pathway inhibitors may prove more successful. Alternatively, supplementation with amino acid-derived metabolites rather than the parent molecule may elicit beneficial effects while bypassing potentially harmful pathways of metabolism. Finally, there is an emerging recognition that circulating levels of multiple amino acids are perturbed in vascular disease and that a more holistic approach that targets all these amino acid derangements is required to restore circulatory function in diseased blood vessels.


Assuntos
Aminoácidos/metabolismo , Sistema Cardiovascular/metabolismo , Saúde , Animais , Doenças Cardiovasculares/metabolismo , Endotélio Vascular/metabolismo , Humanos , Doenças Metabólicas/metabolismo , Óxido Nítrico/metabolismo
4.
Metabolism ; 109: 154223, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32275972

RESUMO

OBJECTIVE: Obesity is associated with myocardial fibrosis and impaired diastolic relaxation, abnormalities that are especially prevalent in women. Normal coronary vascular endothelial function is integral in mediating diastolic relaxation, and recent work suggests increased activation of the endothelial cell (EC) mineralocorticoid receptor (ECMR) is associated with impaired diastolic relaxation. As the endothelial Na+ channel (EnNaC) is a downstream target of the ECMR, we sought to determine whether EC-specific deletion of the critical alpha subunit, αEnNaC, would prevent diet induced-impairment of diastolic relaxation in female mice. METHODS AND MATERIALS: Female αEnNaC KO mice and littermate controls were fed a Western diet (WD) high in fat (46%), fructose corn syrup (17.5%) and sucrose (17.5%) for 12-16 weeks. Measurements were conducted for in vivo cardiac function, in vitro cardiomyocyte stiffness and EnNaC activity in primary cultured ECs. Additional biochemical studies examined indicators of oxidative stress, including aspects of antioxidant Nrf2 signaling, in cardiac tissue. RESULTS: Deletion of αEnNaC in female mice fed a WD significantly attenuated WD mediated impairment in diastolic relaxation. Improved cardiac relaxation was accompanied by decreased EnNaC-mediated Na+ currents in ECs and reduced myocardial oxidative stress. Further, deletion of αEnNaC prevented WD-mediated increases in isolated cardiomyocyte stiffness. CONCLUSION: Collectively, these findings support the notion that WD feeding in female mice promotes activation of EnNaC in the vasculature leading to increased cardiomyocyte stiffness and diastolic dysfunction.


Assuntos
Diástole/efeitos dos fármacos , Dieta Ocidental/efeitos adversos , Células Endoteliais/química , Coração/fisiopatologia , Canais de Sódio/metabolismo , Rigidez Vascular/efeitos dos fármacos , Animais , Células Cultivadas , Células Endoteliais/metabolismo , Feminino , Camundongos , Camundongos Knockout , Miócitos Cardíacos/patologia , Estresse Oxidativo , Canais de Sódio/deficiência
5.
Redox Biol ; 32: 101527, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32278282

RESUMO

Recent cardiovascular outcome trials found that sodium-glucose cotransporter-2 (SGLT2) inhibitors reduce cardiovascular disease and mortality in type 2 diabetic patients; however, the underlying mechanisms are not fully known. Since the proliferation and migration of vascular smooth muscle cells (SMCs) contributes to the development of arterial lesions, we hypothesized that SGLT2 inhibitors may exert their beneficial cardiovascular effects by inhibiting the growth and movement of vascular SMCs. Treatment of rat or human aortic SMCs with clinically relevant concentrations of canagliflozin, but not empagliflozin or dapagliflozin, inhibited cell proliferation and migration. The inhibition of SMC growth by canagliflozin occurred in the absence of cell death, and was associated with the arrest of SMCs in the G0/G1 phase of the cell cycle and diminished DNA synthesis. Canagliflozin also resulted in the induction of heme oxygenase-1 (HO-1) expression, and a rise in HO activity in vascular SMCs, whereas, empagliflozin or dapagliflozin had no effect on HO activity. Canagliflozin also activated the HO-1 promoter and this was abrogated by mutating the antioxidant responsive element or by overexpressing dominant-negative NF-E2-related factor-2 (Nrf2). The induction of HO-1 by canagliflozin relied on reactive oxygen species (ROS) formation and was negated by antioxidants. Finally, silencing HO-1 expression partially rescued the proliferative and migratory response of canagliflozin-treated SMCs, and this was reversed by carbon monoxide and bilirubin. In conclusion, the present study identifies canagliflozin as a novel inhibitor of vascular SMC proliferation and migration. Moreover, it demonstrates that canagliflozin stimulates the expression of HO-1 in vascular SMCs via the ROS-Nrf2 pathway, and that the induction of HO-1 contributes to the cellular actions of canagliflozin. The ability of canagliflozin to exert these pleiotropic effects may contribute to the favorable clinical actions of the drug and suggest an extra potential benefit of canagliflozin relative to other SGLT2 inhibitors.


Assuntos
Heme Oxigenase-1 , Músculo Liso Vascular , Animais , Canagliflozina/farmacologia , Proliferação de Células , Células Cultivadas , Heme Oxigenase (Desciclizante) , Heme Oxigenase-1/genética , Humanos , Miócitos de Músculo Liso , Ratos
6.
Nutrients ; 11(9)2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31487814

RESUMO

Emerging evidence indicates that l-glutamine (Gln) plays a fundamental role in cardiovascular physiology and pathology. By serving as a substrate for the synthesis of DNA, ATP, proteins, and lipids, Gln drives critical processes in vascular cells, including proliferation, migration, apoptosis, senescence, and extracellular matrix deposition. Furthermore, Gln exerts potent antioxidant and anti-inflammatory effects in the circulation by inducing the expression of heme oxygenase-1, heat shock proteins, and glutathione. Gln also promotes cardiovascular health by serving as an l-arginine precursor to optimize nitric oxide synthesis. Importantly, Gln mitigates numerous risk factors for cardiovascular disease, such as hypertension, hyperlipidemia, glucose intolerance, obesity, and diabetes. Many studies demonstrate that Gln supplementation protects against cardiometabolic disease, ischemia-reperfusion injury, sickle cell disease, cardiac injury by inimical stimuli, and may be beneficial in patients with heart failure. However, excessive shunting of Gln to the Krebs cycle can precipitate aberrant angiogenic responses and the development of pulmonary arterial hypertension. In these instances, therapeutic targeting of the enzymes involved in glutaminolysis such as glutaminase-1, Gln synthetase, glutamate dehydrogenase, and amino acid transaminase has shown promise in preclinical models. Future translation studies employing Gln delivery approaches and/or glutaminolysis inhibitors will determine the success of targeting Gln in cardiovascular disease.


Assuntos
Doenças Cardiovasculares/metabolismo , Glutamina/metabolismo , Células Endoteliais/metabolismo , Humanos , Doenças Metabólicas/metabolismo
7.
Front Pharmacol ; 10: 362, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31057401

RESUMO

Recent clinical trials revealed that sodium-glucose co-transporter 2 (SGLT2) inhibitors significantly reduce cardiovascular events in type 2 diabetic patients, however, canagliflozin increased limb amputations, an effect not seen with other SGLT2 inhibitors. Since endothelial cell (EC) dysfunction promotes diabetes-associated vascular disease and limb ischemia, we hypothesized that canagliflozin, but not other SGLT2 inhibitors, impairs EC proliferation, migration, and angiogenesis. Treatment of human umbilical vein ECs (HUVECs) with clinically relevant concentrations of canagliflozin, but not empagliflozin or dapagliflozin, inhibited cell proliferation. In particular, 10 µM canagliflozin reduced EC proliferation by approximately 45%. The inhibition of EC growth by canagliflozin occurred in the absence of cell death and was associated with diminished DNA synthesis, cell cycle arrest, and a striking decrease in cyclin A expression. Restoration of cyclin A expression via adenoviral-mediated gene transfer partially rescued the proliferative response of HUVECs treated with canagliflozin. A high concentration of canagliflozin (50 µM) modestly inhibited HUVEC migration by 20%, but markedly attenuated their tube formation by 65% and EC sprouting from mouse aortas by 80%. A moderate 20% reduction in HUVEC migration was also observed with a high concentration of empagliflozin (50 µM), while neither empagliflozin nor dapagliflozin affected tube formation by HUVECs. The present study identified canagliflozin as a robust inhibitor of human EC proliferation and tube formation. The anti-proliferative action of canagliflozin occurs in the absence of cell death and is due, in part, to the blockade of cyclin A expression. Notably, these actions are not seen with empagliflozin or dapagliflozin. The ability of canagliflozin to exert these pleiotropic effects on ECs may contribute to the clinical actions of this drug.

8.
Biochem Pharmacol ; 156: 204-214, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30144404

RESUMO

Glutaminase-1 (GLS1) is a mitochondrial enzyme found in endothelial cells (ECs) that metabolizes glutamine to glutamate and ammonia. Although glutaminolysis modulates the function of human umbilical vein ECs, it is not known whether these findings extend to human ECs beyond the fetal circulation. Furthermore, the molecular mechanism by which GLS1 regulates EC function is not defined. In this study, we show that the absence of glutamine in the culture media or the inhibition of GLS1 activity or expression blocked the proliferation and migration of ECs derived from the human umbilical vein, the human aorta, and the human microvasculature. GLS1 inhibition arrested ECs in the G0/G1 phase of the cell cycle and this was associated with a significant decline in cyclin A expression. Restoration of cyclin A expression via adenoviral-mediated gene transfer improved the proliferative, but not the migratory, response of GLS1-inhibited ECs. Glutamine deprivation or GLS1 inhibition also stimulated the production of reactive oxygen species and this was associated with a marked decline in heme oxygenase-1 (HO-1) expression. GLS1 inhibition also sensitized ECs to the cytotoxic effect of hydrogen peroxide and this was prevented by the overexpression of HO-1. In conclusion, the metabolism of glutamine by GLS1 promotes human EC proliferation, migration, and survival irrespective of the vascular source. While cyclin A contributes to the proliferative action of GLS1, HO-1 mediates its pro-survival effect. These results identify GLS1 as a promising therapeutic target in treating diseases associated with aberrant EC proliferation, migration, and viability.


Assuntos
Movimento Celular/fisiologia , Proliferação de Células/fisiologia , Células Endoteliais/enzimologia , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Glutaminase/metabolismo , Glutamina/farmacologia , Aorta/citologia , Benzenoacetamidas/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Ciclina A/genética , Ciclina A/metabolismo , Diazo-Oxo-Norleucina/farmacologia , Células Endoteliais/efeitos dos fármacos , Glutaminase/antagonistas & inibidores , Glutaminase/genética , Heme Oxigenase-1/genética , Heme Oxigenase-1/metabolismo , Humanos , Interferência de RNA , Tiadiazóis/farmacologia , Veias/citologia
9.
Amino Acids ; 50(6): 747-754, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29700652

RESUMO

This study investigated the temporal activation of arginase in obese Zucker rats (ZR) and determined if arginase inhibition prevents the development of hypertension and improves insulin resistance in these animals. Arginase activity, plasma arginine and nitric oxide (NO) concentration, blood pressure, and insulin resistance were measured in lean and obese animals. There was a chronological increase in vascular and plasma arginase activity in obese ZR beginning at 8 weeks of age. The increase in arginase activity in obese animals was associated with a decrease in insulin sensitivity and circulating levels of arginine and NO. The rise in arginase activity also preceded the increase in blood pressure in obese ZR detected at 12 weeks of age. Chronic treatment of 8-week-old obese animals with an arginase inhibitor or L-arginine for 4 weeks prevented the development of hypertension and improved plasma concentrations of arginine and NO. Arginase inhibition also improved insulin sensitivity in obese ZR while L-arginine supplementation had no effect. In conclusion, arginase inhibition prevents the development of hypertension and improves insulin sensitivity while L-arginine administration only mitigates hypertension in obese animals. Arginase represents a promising therapeutic target in ameliorating obesity-associated vascular and metabolic dysfunction.


Assuntos
Arginase/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Hipertensão/tratamento farmacológico , Resistência à Insulina , Obesidade/tratamento farmacológico , Animais , Arginase/metabolismo , Arginina/sangue , Hipertensão/sangue , Masculino , Óxido Nítrico/sangue , Obesidade/sangue , Ratos , Ratos Zucker
10.
Am J Physiol Heart Circ Physiol ; 313(5): H988-H999, 2017 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-28822969

RESUMO

Activation of large-conductance Ca2+-activated K+ (BKCa) channels evokes cell survival programs that mitigate intestinal ischemia and reperfusion (I/R) inflammation and injury 24 h later. The goal of the present study was to determine the roles of reactive oxygen species (ROS) and heme oxygenase (HO)-1 in delayed acquisition of tolerance to I/R induced by pretreatment with the BKCa channel opener NS-1619. Superior mesentery arteries were occluded for 45 min followed by reperfusion for 70 min in wild-type (WT) or HO-1-null (HO-1-/-) mice that were pretreated with NS-1619 or saline vehicle 24 h earlier. Intravital microscopy was used to quantify the numbers of rolling and adherent leukocytes. Mucosal permeability, tumor necrosis factor-α (TNF-α) levels, and HO-1 activity and expression in jejunum were also determined. I/R induced leukocyte rolling and adhesion, increased intestinal TNF-α levels, and enhanced mucosal permeability in WT mice, effects that were largely abolished by pretreatment with NS-1619. The anti-inflammatory and mucosal permeability-sparing effects of NS-1619 were prevented by coincident treatment with the HO-1 inhibitor tin protoporphyrin-IX or a cell-permeant SOD mimetic, Mn(III)tetrakis (4-benzoic acid) porphyrin (MnTBAP), in WT mice. NS-1619 also increased jejunal HO-1 activity in WT animals, an effect that was attenuated by treatment with the BKCa channel antagonist paxilline or MnTBAP. I/R also increased postischemic leukocyte rolling and adhesion and intestinal TNF-α levels in HO-1-/- mice to levels comparable to those noted in WT animals. However, NS-1619 was ineffective in preventing these effects in HO-1-deficient mice. In summary, our data indicate that NS-1619 induces the development of an anti-inflammatory phenotype and mitigates postischemic mucosal barrier disruption in the small intestine by a mechanism that may involve ROS-dependent HO-1 activity.NEW & NOTEWORTHY Antecedent treatment with the large-conductance Ca2+-activated K+ channel opener NS-1619 24 h before ischemia-reperfusion limits postischemic tissue injury by an oxidant-dependent mechanism. The present study shows that NS-1619-induced oxidant production prevents ischemia-reperfusion-induced inflammation and mucosal barrier disruption in the small intestine by provoking increases in heme oxygenase-1 activity.


Assuntos
Benzimidazóis/farmacologia , Heme Oxigenase-1/efeitos dos fármacos , Inflamação/prevenção & controle , Canais de Potássio Ativados por Cálcio de Condutância Alta/agonistas , Proteínas de Membrana/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Traumatismo por Reperfusão/prevenção & controle , Animais , Heme Oxigenase-1/genética , Inflamação/etiologia , Precondicionamento Isquêmico , Leucócitos/efeitos dos fármacos , Leucócitos/enzimologia , Leucócitos/metabolismo , Ativação de Macrófagos , Masculino , Proteínas de Membrana/genética , Artéria Mesentérica Superior/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Membrana Mucosa/patologia , Traumatismo por Reperfusão/complicações , Traumatismo por Reperfusão/fisiopatologia , Superóxido Dismutase/antagonistas & inibidores , Superóxido Dismutase/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
11.
Metabolism ; 66: 14-22, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27923445

RESUMO

OBJECTIVE: Obesity is a global epidemic with profound cardiovascular disease (CVD) complications. Obese women are particularly vulnerable to CVD, suffering higher rates of CVD compared to non-obese females. Diastolic dysfunction is the earliest manifestation of CVD in obese women but remains poorly understood with no evidence-based therapies. We have shown early diastolic dysfunction in obesity is associated with oxidative stress and myocardial fibrosis. Recent evidence suggests exercise may increase levels of the antioxidant heme oxygenase-1 (HO-1). Accordingly, we hypothesized that diastolic dysfunction in female mice consuming a western diet (WD) could be prevented by daily volitional exercise with reductions in oxidative stress, myocardial fibrosis and maintenance of myocardial HO-1 levels. MATERIALS/METHODS: Four-week-old female C57BL/6J mice were fed a high-fat/high-fructose WD for 16weeks (N=8) alongside control diet fed mice (N=8). A separate cohort of WD fed females was allowed a running wheel for the entire study (N=7). Cardiac function was assessed at 20weeks by high-resolution cardiac magnetic resonance imaging (MRI). Functional assessment was followed by immunohistochemistry, transmission electron microscopy (TEM) and Western blotting to identify pathologic mechanisms and assess HO-1 protein levels. RESULTS: There was no significant body weight decrease in exercising mice, normalized body weight 14.3g/mm, compared to sedentary mice, normalized body weight 13.6g/mm (p=0.38). Total body fat was also unchanged in exercising, fat mass of 6.6g, compared to sedentary mice, fat mass 7.4g (p=0.55). Exercise prevented diastolic dysfunction with a significant reduction in left ventricular relaxation time to 23.8ms for exercising group compared to 33.0ms in sedentary group (p<0.01). Exercise markedly reduced oxidative stress and myocardial fibrosis with improved mitochondrial architecture. HO-1 protein levels were increased in the hearts of exercising mice compared to sedentary WD fed females. CONCLUSIONS: This study provides seminal evidence that exercise can prevent diastolic dysfunction in WD-induced obesity in females even without changes in body weight. Furthermore, the reduction in myocardial oxidative stress and fibrosis and improved HO-1 levels in exercising mice suggests a novel mechanism for the antioxidant effect of exercise.


Assuntos
Cardiomiopatias/prevenção & controle , Diástole , Heme Oxigenase-1/metabolismo , Miocárdio/metabolismo , Obesidade/terapia , Condicionamento Físico Animal/fisiologia , Animais , Cardiomiopatias/patologia , Cardiomiopatias/fisiopatologia , Ritmo Circadiano , Dieta Ocidental , Modelos Animais de Doenças , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Obesidade/metabolismo , Obesidade/patologia , Obesidade/fisiopatologia , Estresse Oxidativo
12.
Free Radic Biol Med ; 102: 37-46, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27867098

RESUMO

Although endothelial cells produce substantial quantities of ammonia during cell metabolism, the physiologic role of this gas in these cells is not known. In this study, we investigated if ammonia regulates the expression of heme oxygenase-1 (HO-1), and if this enzyme influences the biological actions of ammonia on endothelial cells. Exogenously administered ammonia, given as ammonium chloride or ammonium hydroxide, or endogenously generated ammonia stimulated HO-1 protein expression in cultured human and murine endothelial cells. Dietary supplementation of ammonia also induced HO-1 protein expression in murine arteries. The increase in HO-1 protein by ammonia in endothelial cells was first detected 4h after ammonia exposure and was associated with the induction of HO-1 mRNA, enhanced production of reactive oxygen species (ROS), and increased expression and activity of NF-E2-related factor-2 (Nrf2). Ammonia also activated the HO-1 promoter and this was blocked by mutating the antioxidant responsive element or by overexpressing dominant-negative Nrf2. The induction of HO-1 expression by ammonia was dependent on ROS formation and prevented by N-acetylcysteine or rotenone. Finally, prior treatment of endothelial cells with ammonia inhibited tumor necrosis factor-α-stimulated cell death. However, silencing HO-1 expression abrogated the protective action of ammonia and this was reversed by the administration of carbon monoxide but not bilirubin or iron. In conclusion, this study demonstrates that ammonia stimulates the expression of HO-1 in endothelial cells via the ROS-Nrf2 pathway, and that the induction of HO-1 contributes to the cytoprotective action of ammonia by generating carbon monoxide. Moreover, it identifies ammonia as a potentially important signaling gas in the vasculature that promotes endothelial cell survival.


Assuntos
Amônia/metabolismo , Células Endoteliais/metabolismo , Heme Oxigenase-1/genética , Fator 2 Relacionado a NF-E2/genética , Acetilcisteína/administração & dosagem , Amônia/administração & dosagem , Cloreto de Amônio/administração & dosagem , Animais , Artérias/efeitos dos fármacos , Artérias/metabolismo , Monóxido de Carbono/administração & dosagem , Sobrevivência Celular/efeitos dos fármacos , Células Endoteliais/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Heme Oxigenase-1/biossíntese , Humanos , Camundongos , Fator 2 Relacionado a NF-E2/metabolismo , Regiões Promotoras Genéticas/genética , Espécies Reativas de Oxigênio/metabolismo , Rotenona/administração & dosagem , Transdução de Sinais/efeitos dos fármacos , Fator de Necrose Tumoral alfa/genética
16.
Free Radic Biol Med ; 94: 218-29, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-26968795

RESUMO

The use of HIV protease inhibitors (PIs) has extended the duration and quality of life for HIV-positive individuals. However there is increasing concern that this antiviral therapy may promote premature cardiovascular disease by impairing endothelial cell (EC) function. In the present study, we investigated the effect of HIV PIs on EC function and determined if the enzyme heme oxygenase (HO-1) influences the biological action of these drugs. We found that three distinct PIs, including ritonavir, atazanavir, and lopinavir, stimulated the expression of HO-1 protein and mRNA. The induction of HO-1 was associated with an increase in NF-E2-related factor-2 (Nrf2) activity and reactive oxygen species (ROS). PIs also stimulated HO-1 promoter activity and this was prevented by mutating the antioxidant responsive element or by overexpressing dominant-negative Nrf2. In addition, the PI-mediated induction of HO-1 was abolished by N-acetyl-l-cysteine and rotenone. Furthermore, PIs blocked EC proliferation and migration and stimulated the expression of intercellular adhesion molecule-1 and the adhesion of monocytes on ECs. Inhibition of HO-1 activity or expression potentiated the anti-proliferative and inflammatory actions of PIs which was reversed by bilirubin but not carbon monoxide. Alternatively, adenovirus-mediated overexpression of HO-1 attenuated the growth-inhibitory and inflammatory effect of PIs. In contrast, blocking HO-1 activity failed to modify the anti-migratory effect of the PIs. Thus, induction of HO-1 via the ROS-Nrf2 pathway in human ECs counteracts the anti-proliferative and inflammatory actions of PIs by generating bilirubin. Therapeutic approaches targeting HO-1 may provide a novel approach in preventing EC dysfunction and vascular disease in HIV-infected patients undergoing antiretroviral therapy.


Assuntos
Bilirrubina/metabolismo , Doenças Cardiovasculares/tratamento farmacológico , Infecções por HIV/tratamento farmacológico , Heme Oxigenase-1/genética , Fator 2 Relacionado a NF-E2/genética , Acetilcisteína/administração & dosagem , Sulfato de Atazanavir/administração & dosagem , Sulfato de Atazanavir/efeitos adversos , Doenças Cardiovasculares/induzido quimicamente , Doenças Cardiovasculares/virologia , Proliferação de Células/efeitos dos fármacos , Células Endoteliais/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Infecções por HIV/virologia , Inibidores da Protease de HIV/administração & dosagem , Inibidores da Protease de HIV/efeitos adversos , Heme Oxigenase-1/antagonistas & inibidores , Heme Oxigenase-1/metabolismo , Humanos , Lopinavir/administração & dosagem , Lopinavir/efeitos adversos , Regiões Promotoras Genéticas/genética , Espécies Reativas de Oxigênio/metabolismo , Ritonavir/administração & dosagem , Ritonavir/efeitos adversos , Rotenona/administração & dosagem
17.
Front Biosci (Elite Ed) ; 8: 205-12, 2016 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-26709656

RESUMO

The vascular endothelium is continuously exposed to cyclic mechanical strain due to the periodic change in vessel diameter as a result of pulsatile blood flow. Since emerging evidence indicates the cyclic strain plays an integral role in regulating endothelial cell function, the present study determined whether application of a physiologic regimen of cyclic strain (6% at 1 hertz) influences the proliferation of human arterial endothelial cells. Prolonged exposure of human dermal microvascular or human aortic endothelial cells to cyclic strain for up to 7 days resulted in a marked decrease in cell growth. The strain-mediated anti-proliferative effect was associated with the arrest of endothelial cells in the G2/M phase of the cell cycle, did not involve cell detachment or cytotoxicity, and was due to the induction of p21. Interestingly, the inhibition in endothelial cell growth was independent of the strain regimen since prolonged application of constant or intermittent 6% strain was also able to block endothelial cell proliferation. The ability of chronic physiologic cyclic strain to inhibit endothelial cell growth represents a previously unrecognized mechanism by which hemodynamic forces maintain these cells in a quiescent, non-proliferative state.


Assuntos
Proliferação de Células , Endotélio Vascular/citologia , Estresse Mecânico , Células Cultivadas , Endotélio Vascular/enzimologia , Indução Enzimática , Humanos , Quinases Ativadas por p21/biossíntese
19.
Obesity (Silver Spring) ; 23(2): 383-90, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25557182

RESUMO

OBJECTIVE: This study investigated whether arginase contributes to endothelial dysfunction and hypertension in obese rats. METHODS: Endothelial function and arginase expression were examined in skeletal muscle arterioles from lean and obese Zucker rats (ZRs). Arginase activity, arginine bioavailability, and blood pressure were measured in lean and obese animals. RESULTS: Arginase activity and expression was increased while global arginine bioavailability decreased in obese ZRs. Acetylcholine or luminal flow caused dilation of isolated skeletal muscle arterioles, but this was reduced or absent in vessels from obese ZRs. Treatment of arterioles with a nitric oxide synthase inhibitor blocked dilation in lean arterioles and eliminated differences among lean and obese vessels. In contrast, arginase inhibitors or l-arginine enhanced vasodilation in obese ZRs and abolished differences between lean and obese animals, while d-arginine had no effect. Finally, mean arterial blood pressure was significantly increased in obese ZRs. However, administration of l-arginine or arginase inhibitors lowered blood pressure in obese but not lean animals, and this was associated with an improvement in systemic arginine bioavailability. CONCLUSIONS: Arginase promotes endothelial dysfunction and hypertension in obesity by reducing arginine bioavailability. Therapeutic approaches targeting arginase represent a promising approach in treating obesity-related vascular disease.


Assuntos
Arginase/genética , Endotélio Vascular/fisiopatologia , Regulação da Expressão Gênica , Hipertensão/genética , Obesidade/complicações , RNA/genética , Vasodilatação/fisiologia , Animais , Arginase/biossíntese , Arteríolas/enzimologia , Arteríolas/fisiopatologia , Pressão Sanguínea/fisiologia , Modelos Animais de Doenças , Endotélio Vascular/enzimologia , Hipertensão/enzimologia , Hipertensão/fisiopatologia , Masculino , Obesidade/enzimologia , Obesidade/genética , Ratos , Ratos Zucker , Reação em Cadeia da Polimerase em Tempo Real
20.
Biochem Pharmacol ; 87(2): 303-11, 2014 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-24239896

RESUMO

Endothelial cell (EC) dysfunction is involved in the pathogenesis of contrast-induced acute kidney injury, which is a major adverse event following coronary angiography. In this study, we evaluated the effect of contrast media (CM) on human EC proliferation, migration, and inflammation, and determined if heme oxygenase-1 (HO-1) influences the biological actions of CM. We found that three distinct CM, including high-osmolar (diatrizoate), low-osmolar (iopamidol), and iso-osmolar (iodixanol), stimulated the expression of HO-1 protein and mRNA. The induction of HO-1 was associated with an increase in NF-E2-related factor-2 (Nrf2) activity and reactive oxygen species (ROS). CM also stimulated HO-1 promoter activity and this was prevented by mutating the antioxidant responsive element or by overexpressing dominant-negative Nrf2. In addition, the CM-mediated induction of HO-1 and activation of Nrf2 was abolished by acetylcysteine. Finally, CM inhibited the proliferation and migration of ECs and stimulated the expression of intercellular adhesion molecule-1 and the adhesion of monocytes on ECs. Inhibition or silencing of HO-1 exacerbated the anti-proliferative and inflammatory actions of CM but had no effect on the anti-migratory effect. Thus, induction of HO-1 via the ROS-Nrf2 pathway counteracts the anti-proliferative and inflammatory actions of CM. Therapeutic approaches targeting HO-1 may provide a novel approach in preventing CM-induced endothelial and organ dysfunction.


Assuntos
Meios de Contraste/toxicidade , Células Endoteliais/enzimologia , Células Endoteliais/patologia , Heme Oxigenase-1/fisiologia , Proliferação de Células/efeitos dos fármacos , Angiografia Coronária/efeitos adversos , Angiografia Coronária/métodos , Células Endoteliais/efeitos dos fármacos , Heme Oxigenase-1/farmacologia , Células Endoteliais da Veia Umbilical Humana , Humanos , Inflamação/induzido quimicamente , Inflamação/metabolismo , Inflamação/patologia , Células U937
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