RESUMO
Increasing evidence implicates endothelial dysfunction in the pathogenesis of Alzheimer's disease (AD). Nitric oxide (NO) derived from endothelial NO synthase (eNOS) is essential in maintaining cerebrovascular function and can modulate the production and clearance of amyloid beta (Aß). APPswe/PSdE1 (APP/PS1) mice display age-related Aß accumulation and memory deficits. In order to make the model more clinically relevant with an element of endothelial dysfunction, we generated APP/PS1/eNOS+/- mice by crossing complete eNOS deficient (eNOS-/-) mice and APP/PS1 mice. APP/PS1/eNOS+/- mice at 8 months of age displayed a more severe spatial working memory deficit relative to age-matched APP/PS1 mice. Moreover, immunohistochemistry and immunoblotting revealed significantly increased Aß plaque load in the brains of APP/PS1/eNOS+/- mice, concomitant with upregulated BACE-1 (hence increased Aß production), downregulated insulin-degrading enzyme (hence reduced Aß clearance) and increased immunoreactivity and expression of microglia. The present study, for the first time, demonstrated that partial eNOS deficiency exacerbated behavioral dysfunction, Aß brain deposition, and microglial pathology in APP/PS1 mice, further implicating endothelial dysfunction in the pathogenesis of AD. The present findings also provide the scientific basis for developing preventive and/or therapeutic strategies by targeting endothelial dysfunction.
Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Óxido Nítrico Sintase Tipo III , Doença de Alzheimer/enzimologia , Doença de Alzheimer/metabolismo , Doença de Alzheimer/psicologia , Peptídeos beta-Amiloides/genética , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Disfunção Cognitiva/enzimologia , Disfunção Cognitiva/genética , Disfunção Cognitiva/metabolismo , Modelos Animais de Doenças , Transtornos da Memória/genética , Transtornos da Memória/metabolismo , Camundongos , Camundongos Transgênicos , Óxido Nítrico Sintase Tipo III/deficiência , Óxido Nítrico Sintase Tipo III/genética , Óxido Nítrico Sintase Tipo III/metabolismo , Placa Amiloide/metabolismo , Presenilina-1/metabolismoRESUMO
AIMS/HYPOTHESIS: It was shown that maternal endothelial nitric oxide synthase (eNOS) deficiency causes fatty liver disease and numerically lower fasting glucose in female wild-type offspring, suggesting that parental genetic variants may influence the offspring's phenotype via epigenetic modifications in the offspring despite the absence of a primary genetic defect. The aim of the current study was to analyse whether paternal eNOS deficiency may cause the same phenotype as seen with maternal eNOS deficiency. METHODS: Heterozygous (+/-) male eNOS (Nos3) knockout mice or wild-type male mice were bred with female wild-type mice. The phenotype of wild-type offspring of heterozygous male eNOS knockout mice was compared with offspring from wild-type parents. RESULTS: Global sperm DNA methylation decreased and sperm microRNA pattern altered substantially. Fasting glucose and liver glycogen storage were increased when analysing wild-type male and female offspring of +/- eNOS fathers. Wild-type male but not female offspring of +/- eNOS fathers had increased fasting insulin and increased insulin after glucose load. Analysing candidate genes for liver fat and carbohydrate metabolism revealed that the expression of genes encoding glucocorticoid receptor (Gr; also known as Nr3c1) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (Pgc1a; also known as Ppargc1a) was increased while DNA methylation of Gr exon 1A and Pgc1a promoter was decreased in the liver of male wild-type offspring of +/- eNOS fathers. The endocrine pancreas in wild-type offspring was not affected. CONCLUSIONS/INTERPRETATION: Our study suggests that paternal genetic defects such as eNOS deficiency may alter the epigenome of the sperm without transmission of the paternal genetic defect itself. In later life wild-type male offspring of +/- eNOS fathers developed increased fasting insulin and increased insulin after glucose load. These effects are associated with increased Gr and Pgc1a gene expression due to altered methylation of these genes.
Assuntos
Glucose , Glicogênio Hepático , Óxido Nítrico Sintase Tipo III , Animais , Feminino , Glucose/metabolismo , Homeostase , Insulina/metabolismo , Glicogênio Hepático/metabolismo , Masculino , Camundongos , Camundongos Knockout , Óxido Nítrico Sintase Tipo III/deficiência , Óxido Nítrico Sintase Tipo III/genética , Óxido Nítrico Sintase Tipo III/metabolismoRESUMO
Endothelial nitric oxide synthase (eNOS) dysfunction is known to exacerbate the progression and prognosis of diabetic kidney disease (DKD). One of the mechanisms through which this is achieved is that low eNOS levels are associated with hypercoagulability, which promotes kidney injury. In the extrinsic coagulation cascade, the tissue factor (factor III) and downstream coagulation factors, such as active factor X (FXa), exacerbate inflammation through activation of the protease-activated receptors (PARs). Recently, it has been shown that the lack of or reduced eNOS expression in diabetic mice, as a model of advanced DKD, increases renal tissue factor levels and PAR1 and 2 expression in their kidneys. Furthermore, pharmaceutical inhibition or genetic deletion of coagulation factors or PARs ameliorated inflammation in DKD in mice lacking eNOS. In this review, we summarize the relationship between eNOS, coagulation, and PARs and propose a novel therapeutic option for the management of patients with DKD.
Assuntos
Nefropatias Diabéticas/etiologia , Óxido Nítrico Sintase Tipo III/deficiência , Receptores Ativados por Proteinase/metabolismo , Animais , Anticorpos Neutralizantes/administração & dosagem , Coagulação Sanguínea , Nefropatias Diabéticas/sangue , Nefropatias Diabéticas/fisiopatologia , Modelos Animais de Doenças , Inibidores do Fator Xa/farmacologia , Humanos , Rim/efeitos dos fármacos , Rim/metabolismo , Camundongos , Camundongos Knockout , Óxido Nítrico Sintase Tipo III/genética , Receptores Ativados por Proteinase/deficiência , Receptores Ativados por Proteinase/genética , Transdução de Sinais , Tromboplastina/antagonistas & inibidores , Tromboplastina/metabolismoRESUMO
Decreases in arterial blood oxygen stimulate increases in minute ventilation via activation of peripheral and central respiratory structures. This study evaluates the role of endothelial nitric oxide synthase (eNOS) in the expression of the ventilatory responses during and following a hypoxic gas challenge (HXC, 10% O2, 90% N2) in freely moving male and female wild-type (WT) C57BL6 and eNOS knock-out (eNOS-/-) mice. Exposure to HXC caused an array of responses (of similar magnitude and duration) in both male and female WT mice such as, rapid increases in frequency of breathing, tidal volume, minute ventilation and peak inspiratory and expiratory flows, that were subject to pronounced roll-off. The responses to HXC in male eNOS-/- mice were similar to male WT mice. In contrast, several of the ventilatory responses in female eNOS-/- mice (e.g., frequency of breathing, and expiratory drive) were greater compared to female WT mice. Upon return to room-air, male and female WT mice showed similar excitatory ventilatory responses (i.e., short-term potentiation phase). These responses were markedly reduced in male eNOS-/- mice, whereas female eNOS-/- mice displayed robust post-HXC responses that were similar to those in female WT mice. Our data demonstrates that eNOS plays important roles in (1) ventilatory responses to HXC in female compared to male C57BL6 mice; and (2) expression of post-HXC responses in male, but not female C57BL6 mice. These data support existing evidence that sex, and the functional roles of specific proteins (e.g., eNOS) have profound influences on ventilatory processes, including the responses to HXC.
Assuntos
Hipóxia/metabolismo , Óxido Nítrico Sintase Tipo III/genética , Respiração , Animais , Feminino , Hipóxia/fisiopatologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Óxido Nítrico Sintase Tipo III/deficiência , Óxido Nítrico Sintase Tipo III/metabolismo , Ventilação Pulmonar , Fatores Sexuais , Volume de Ventilação PulmonarRESUMO
The relationship between cellular senescence and fibrosis in the kidney is being elucidated and we have identified it as therapeutic target in recent studies. Chronic kidney disease has also become a lifestyle disease, often developing on the background of hypertension and dyslipidemia. In this study, we clarify the effect of interaction between these two conditions on kidney fibrosis and senescence. Wild type mice (WT), apolipoprotein E-/- mice (ApoEKO), and endothelial nitric oxide synthase (eNOS)-/- ApoE-/- mice (DKO) were obtained by breeding. Unilateral ureteral obstruction (UUO) was performed on 8-10 week old male mice and the degree of renal tubular injury, fibrosis and kidney senescence were evaluated. DKO manifested elevated blood pressure, higher total cholesterol and lower HDL than WT. DKO showed sustained kidney injury molecule-1 protein expression. Kidney fibrosis was significantly higher in ApoEKO and DKO. mRNA expression of genes related to kidney fibrosis was the highest in DKO. The mRNA expression of Zinc-α2-Glycoprotein and heme oxygenase-1 were significantly decreased in DKO. Furthermore, mRNA expression of p53, p21 and p16 were increased both in ApoEKO and DKO, with DKO being the highest. Senescence associated ß-gal positive tubule area was significantly increased in DKO. Increased DNA damage and target of rapamycin-autophagy spatial coupling compartments (TASCCs) formation was found in DKO. Mice with endothelial dysfunction and dyslipidemia developed kidney fibrosis and accelerated senescence even in young mice after injury. These data highlight the fact managing lifestyle-related diseases from a young age is important for CKD prevention.
Assuntos
Apolipoproteínas E/deficiência , Senescência Celular/genética , Fibrose/genética , Deleção de Genes , Rim/patologia , Óxido Nítrico Sintase Tipo III/deficiência , Insuficiência Renal Crônica/genética , Animais , Apolipoproteínas E/genética , Autofagia , Pressão Sanguínea , Inibidor de Quinase Dependente de Ciclina p21 , Dano ao DNA/genética , Genes p16 , Genes p53 , Humanos , Rim/lesões , Lipídeos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Óxido Nítrico Sintase Tipo III/genética , Serina-Treonina Quinases TOR/metabolismoRESUMO
Age-related cerebral small-vessel disease (CSVD) is a major cause of stroke and dementia. Despite a widespread acceptance of small-vessel arteriopathy, lacunar infarction, diffuse white matter injury, and cognitive impairment as four cardinal features of CSVD, a unifying pathologic mechanism of CSVD remains elusive. Herein, we introduce partial endothelial nitric oxide synthase (eNOS)-deficient mice as a model of age-dependent, spontaneous CSVD. These mice developed cerebral hypoperfusion and blood-brain barrier leakage at a young age, which progressively worsened with advanced age. Their brains exhibited elevated oxidative stress, astrogliosis, cerebral amyloid angiopathy, microbleeds, microinfarction, and white matter pathology. Partial eNOS-deficient mice developed gait disturbances at middle age, and hippocampus-dependent memory deficits at older ages. These mice also showed enhanced expression of bone morphogenetic protein 4 (BMP4) in brain pericytes before myelin loss and white matter pathology. Because BMP4 signaling not only promotes astrogliogenesis but also blocks oligodendrocyte differentiation, we posit that paracrine actions of BMP4, localized within the neurovascular unit, promote white matter disorganization and neurodegeneration. These observations point to BMP4 signaling pathway in the aging brain vasculature as a potential therapeutic target. Finally, because studies in partial eNOS-deficient mice corroborated recent clinical evidence that blood-brain barrier disruption is a primary cause of white matter pathology, the mechanism of impaired nitric oxide signaling-mediated CSVD warrants further investigation.
Assuntos
Proteína Morfogenética Óssea 4/metabolismo , Doenças de Pequenos Vasos Cerebrais/metabolismo , Doenças de Pequenos Vasos Cerebrais/fisiopatologia , Modelos Animais de Doenças , Óxido Nítrico Sintase Tipo III/deficiência , Animais , Doenças de Pequenos Vasos Cerebrais/patologia , CamundongosRESUMO
Since the treatment window of thrombolytic therapy for stroke is limited, new therapy remains to be developed. We have recently developed low-intensity pulsed ultrasound (LIPUS) therapy to improve cognitive dysfunction in mouse models of vascular dementia and Alzheimer's disease. Here, we further aimed to examine whether our LIPUS therapy improves neurological recovery from ischemic stroke, and if so, to elucidate the mechanisms involved. In a mouse model of middle cerebral artery occlusion (MCAO), we applied LIPUS (32 cycles, 193 mW/cm2) to the whole brain 3 times in the first week (days 1, 3, and 5) after MCAO. We evaluated neurological functions using behavioral tests and performed histological analyses. Furthermore, to elucidate how LIPUS works within the injured brain, we also tested the effects of LIPUS in endothelial nitric oxide synthase (eNOS)-deficient (eNOS-/-) mice. In wild-type mice, the LIPUS therapy markedly improved neurological functions in the tightrope and rotarod tests at 28 days after MCAO. Histological analyses showed that the LIPUS therapy significantly increased the numbers of CD31-positive blood vessels in the perifocal lesion and doublecortin (DCX)-positive neurons in the ischemic striatum, indicating the angio-neurogenesis effects of the therapy. Importantly, these beneficial effects of the LIPUS therapy were totally absent in eNOS-/- mice. No adverse effects of the LIPUS therapy were noted. These results indicate that the LIPUS therapy improves neurological functions after stroke through enhanced neuro-angiogenesis in mice in vivo in an eNOS-dependent manner, suggesting that it could a novel and non-invasive therapeutic option for stroke.
Assuntos
Neovascularização Fisiológica , Neurogênese , Óxido Nítrico Sintase Tipo III , Acidente Vascular Cerebral , Terapia por Ultrassom , Ondas Ultrassônicas , Animais , Masculino , Camundongos , Camundongos Knockout , Óxido Nítrico Sintase Tipo III/deficiência , Óxido Nítrico Sintase Tipo III/metabolismo , Acidente Vascular Cerebral/enzimologia , Acidente Vascular Cerebral/genética , Acidente Vascular Cerebral/fisiopatologia , Acidente Vascular Cerebral/terapiaRESUMO
Peroxynitrite (PN), generated from the reaction of nitric oxide (NO) and superoxide, is implicated in the pathogenesis of ischemic and neurodegenerative brain injuries. Mitochondria produce NO from mitochondrial NO synthases and superoxide by the electron transport chain. Our objective was to detect the generation of PN of mitochondrial origin and characterize its effects on mitochondrial respiratory function. Freshly isolated brain nonsynaptosomal mitochondria from C57Bl/6 (wild type, WT) and endothelial NO synthase knockout (eNOS-KO) mice were treated with exogenous PN (0.1, 1, 5 µmol/L) or a PN donor (SIN-1; 50 µmol/L) or a PN scavenger (FeTMPyP; 2.5 µmol/L). Oxygen consumption rate (OCR) was measured using Agilent Seahorse XFe24 analyzer and mitochondrial respiratory parameters were calculated. Mitochondrial membrane potential, superoxide, and PN were determined from rhodamine 123, dihydroethidium, and DAX-J2 PON green fluorescence measurements, respectively. Mitochondrial protein nitrotyrosination was determined by Western blots. Both exogenous PN and SIN-1 decreased respiratory function in WT isolated brain mitochondria. FeTMPyP enhanced state III and state IVo mitochondrial respiration in both WT and eNOS-KO mitochondria. FeTMPyP also elevated state IIIu respiration in eNOS-KO mitochondria. Unlike PN, neither SIN-1 nor FeTMPyP depolarized the mitochondria. Although mitochondrial protein nitrotyrosination was unaffected by SIN-1 or FeTMPyP, FeTMPyP reduced mitochondrial PN levels. Mitochondrial superoxide levels were increased by FeTMPyP but were unaffected by PN or SIN-1. Thus, we present the evidence of functionally significant PN generation in isolated brain mitochondria. Mitochondrial PN activity was physiologically relevant in WT mice and pathologically significant under conditions with eNOS deficiency.NEW & NOTEWORTHY Mitochondria generate superoxide and nitric oxide that could potentially react with each other to produce PN. We observed eNOS and nNOS immunoreactivity in isolated brain and heart mitochondria with pharmacological inhibition of nNOS found to modulate the mitochondrial respiratory function. This study provides evidence of generation of functionally significant PN in isolated brain mitochondria that affects respiratory function under physiological conditions. Importantly, the mitochondrial PN levels and activity were exaggerated in the eNOS-deficient mice, suggesting its pathological significance.
Assuntos
Encéfalo/metabolismo , Mitocôndrias/metabolismo , Óxido Nítrico/metabolismo , Ácido Peroxinitroso/metabolismo , Superóxidos/metabolismo , Animais , Encéfalo/efeitos dos fármacos , Catálise , Respiração Celular , Potencial da Membrana Mitocondrial , Metaloporfirinas/farmacologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mitocôndrias/efeitos dos fármacos , Molsidomina/análogos & derivados , Molsidomina/farmacologia , Óxido Nítrico Sintase Tipo I/metabolismo , Óxido Nítrico Sintase Tipo III/deficiência , Óxido Nítrico Sintase Tipo III/genética , Ácido Peroxinitroso/farmacologia , Espécies Reativas de Oxigênio/metabolismoRESUMO
High salt (HS) intake is usually considered as an aggravating factor to induce inflammatory renal injury. However, the changes in the renal levels of inflammatory cytokines during HS intake is not yet clearly defined. We hypothesize that HS increases renal levels of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) but decreases interleukin-10 (IL-10; anti-inflammatory cytokine) and these responses exacerbate in NO deficient conditions. Both wild-type (WT) and endothelial NO synthase knockout (eNOSKO) mice (~8 weeks old, n = 6 in each group) were given normal-salt (NS; 0.3% NaCl) and HS (4% NaCl) containing diets for 2 weeks. Systolic blood pressure (SBP) was determined by tail-cuff plethysmography and urine collections were made using metabolic cages. Basal SBP was higher in eNOSKO than WT mice (131 ± 7 vs 117 ± 3 mmHg; p < .05). HS intake for 2 weeks increased SBP in eNOSKO (161 ± 5 mmHg) but not in WT mice. In NS groups, the cytokine levels in renal tissues (measured using ELISA kits and expressed in pg/mg protein) were significantly higher in eNOSKO than WT mice (TNF-α, 624 ± 67 vs. 325 ± 73; IL-6, 619 ± 106 vs. 166 ± 61; IL-10, 6,087 ± 567 vs. 3,929 ± 378). Interestingly, these cytokine levels in HS groups were significantly less both in WT (TNF-α, 114 ± 17; IL-6, 81 ± 14; IL-10, 865 ± 130) and eNOSKO (TNF-α, 115 ± 18; IL-6, 56 ± 7; IL-10, 882 ± 141) mice. These findings indicate that HS induces downregulation of cytokines in the kidney. Such HS-induced reduction in cytokines, particularly TNF-α (a natriuretic agent), would facilitate more salt-retention, and thus, leading to salt-sensitive hypertension in NO deficient conditions.
Assuntos
Interleucina-10/metabolismo , Interleucina-6/metabolismo , Rim/metabolismo , Cloreto de Sódio na Dieta/farmacologia , Fator de Necrose Tumoral alfa/metabolismo , Animais , Pressão Sanguínea , Rim/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase Tipo III/deficiência , Óxido Nítrico Sintase Tipo III/genéticaRESUMO
Patients with a congenital bicuspid aortic valve (BAV), a valve with two instead of three aortic leaflets, have an increased risk of developing thoracic aneurysms and aortic dissection. The mechanisms underlying BAV-associated aortopathy are poorly understood. This study examined BAV-associated aortopathy in Nos3-/- mice, a model with congenital BAV formation. A combination of histological examination and in vivo ultrasound imaging was used to investigate aortic dilation and dissections in Nos3-/- mice. Moreover, cell lineage analysis and single-cell RNA sequencing were used to observe the molecular anomalies within vascular smooth muscle cells (VSMCs) of Nos3-/- mice. Spontaneous aortic dissections were found in ascending aortas located at the sinotubular junction in â¼13% of Nos3-/- mice. Moreover, Nos3-/- mice were prone to developing aortic dilations in the proximal and distal ascending aorta during early adulthood. Lower volumes of elastic fibres were found within vessel walls of the ascending aortas of Nos3-/- mice, as well as incomplete coverage of the aortic inner media by neural crest cell (NCC)-derived VSMCs. VSMCs of Nos3-/- mice showed downregulation of 15 genes, of which seven were associated with aortic aneurysms and dissections in the human population. Elastin mRNA was most markedly downregulated, followed by fibulin-5 expression, both primary components of elastic fibres. This study demonstrates that, in addition to congenital BAV formation, disrupted endothelial-mediated nitric oxide (NO) signalling in Nos3-/- mice also causes aortic dilation and dissection, as a consequence of inhibited elastic fibre formation in VSMCs within the ascending aorta.
Assuntos
Aorta/patologia , Doença da Válvula Aórtica Bicúspide/metabolismo , Doença da Válvula Aórtica Bicúspide/patologia , Óxido Nítrico/metabolismo , Transdução de Sinais , Envelhecimento/patologia , Dissecção Aórtica/genética , Dissecção Aórtica/patologia , Animais , Aorta/embriologia , Doença da Válvula Aórtica Bicúspide/genética , Dilatação Patológica , Regulação para Baixo/genética , Embrião de Mamíferos/patologia , Regulação da Expressão Gênica no Desenvolvimento , Variação Genética , Camundongos , Músculo Liso Vascular/patologia , Miócitos de Músculo Liso/metabolismo , Miócitos de Músculo Liso/patologia , Crista Neural/patologia , Óxido Nítrico Sintase Tipo III/deficiência , Óxido Nítrico Sintase Tipo III/metabolismo , FenótipoRESUMO
Protease-activated receptors (PARs) are coagulation protease targets, and they increase expression of inflammatory cytokines and chemokines in various diseases. Of all PARs, previous reports have shown that PAR1 or PAR2 inhibition is protective against diabetic glomerular injury. However, how PAR1 and PAR2 cooperatively contribute to diabetic kidney disease (DKD) pathogenesis and whether dual blockade of PARs is more effective in DKD remain elusive. To address this issue, male type I diabetic Akita mice heterozygous for endothelial nitric oxide synthase were used as a model of DKD. Mice (4 mo old) were divided into four treatment groups and administered vehicle, PAR1 antagonist (E5555, 60 mg·kg-1·day-1), PAR2 antagonist (FSLLRY, 3 mg·kg-1·day-1), or E5555 + FSLLRY for 4 wk. The results showed that the urinary albumin creatinine ratio was significantly reduced when both PAR1 and PAR2 were blocked with E5555 + FSLLRY compared with the vehicle-treated group. Dual blockade of PAR1 and PAR2 by E5555 + FSLLRY additively ameliorated histological injury, including mesangial expansion, glomerular macrophage infiltration, and collagen type IV deposition. Marked reduction of inflammation- and fibrosis-related gene expression in the kidney was also observed. In vitro, PAR1 and PAR2 agonists additively increased mRNA expression of macrophage chemoattractant protein 1 or plasminogen activator inhibitor-1 in human endothelial cells. Changes induced by the PAR1 agonist were blocked by a NF-κB inhibitor, whereas those of the PAR2 agonist were blocked by MAPK and/or NF-κB inhibitors. These findings suggest that PAR1 and PAR2 additively contribute to DKD pathogenesis and that dual blockade of both could be a novel therapeutic option for treatment of patients with DKD.
Assuntos
Diabetes Mellitus Tipo 1/tratamento farmacológico , Nefropatias Diabéticas/prevenção & controle , Iminas/farmacologia , Rim/efeitos dos fármacos , Oligopeptídeos/farmacologia , Piridinas/farmacologia , Receptor PAR-1/antagonistas & inibidores , Receptor PAR-2/antagonistas & inibidores , Albuminúria/genética , Albuminúria/metabolismo , Albuminúria/prevenção & controle , Animais , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Colágeno Tipo IV/metabolismo , Citocinas/metabolismo , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/metabolismo , Nefropatias Diabéticas/genética , Nefropatias Diabéticas/metabolismo , Nefropatias Diabéticas/patologia , Modelos Animais de Doenças , Quimioterapia Combinada , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Fibrose , Humanos , Mediadores da Inflamação/metabolismo , Rim/metabolismo , Rim/patologia , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Camundongos Knockout , Óxido Nítrico Sintase Tipo III/deficiência , Óxido Nítrico Sintase Tipo III/genética , Receptor PAR-1/metabolismo , Receptor PAR-2/metabolismo , Transdução de SinaisRESUMO
Proper brain function depends on neurovascular coupling: neural activity rapidly increases local blood flow to meet moment-to-moment changes in regional brain energy demand1. Neurovascular coupling is the basis for functional brain imaging2, and impaired neurovascular coupling is implicated in neurodegeneration1. The underlying molecular and cellular mechanisms of neurovascular coupling remain poorly understood. The conventional view is that neurons or astrocytes release vasodilatory factors that act directly on smooth muscle cells (SMCs) to induce arterial dilation and increase local blood flow1. Here, using two-photon microscopy to image neural activity and vascular dynamics simultaneously in the barrel cortex of awake mice under whisker stimulation, we found that arteriolar endothelial cells (aECs) have an active role in mediating neurovascular coupling. We found that aECs, unlike other vascular segments of endothelial cells in the central nervous system, have abundant caveolae. Acute genetic perturbations that eliminated caveolae in aECs, but not in neighbouring SMCs, impaired neurovascular coupling. Notably, caveolae function in aECs is independent of the endothelial NO synthase (eNOS)-mediated NO pathway. Ablation of both caveolae and eNOS completely abolished neurovascular coupling, whereas the single mutants exhibited partial impairment, revealing that the caveolae-mediated pathway in aECs is a major contributor to neurovascular coupling. Our findings indicate that vasodilation is largely mediated by endothelial cells that actively relay signals from the central nervous system to SMCs via a caveolae-dependent pathway.
Assuntos
Arteríolas/citologia , Arteríolas/metabolismo , Cavéolas/metabolismo , Sistema Nervoso Central/citologia , Acoplamento Neurovascular , Animais , Córtex Cerebral/citologia , Células Endoteliais/metabolismo , Feminino , Masculino , Camundongos , Microscopia de Fluorescência por Excitação Multifotônica , Óxido Nítrico Sintase Tipo III/deficiência , Óxido Nítrico Sintase Tipo III/metabolismo , Vasodilatação , Vibrissas/fisiologiaRESUMO
OBJECTIVE: Mice genetically deficient in endothelial nitric oxide synthase (Nos3-/-) have fasting hyperinsulinemia and hepatic insulin resistance, indicating the importance of Nos3 (nitric oxide synthase) in maintaining metabolic homeostasis. Although the current paradigm holds that these metabolic effects are derived specifically from the expression of Nos3 in the endothelium, it has been established that bone marrow-derived cells also express Nos3. The aim of this study was to investigate whether bone marrow-derived cell Nos3 is important in maintaining metabolic homeostasis. Approach and Results: To test the hypothesis that bone marrow-derived cell Nos3 contributes to metabolic homeostasis, we generated chimeric male mice deficient or competent for Nos3 expression in circulating blood cells. These mice were placed on a low-fat diet for 5 weeks, a time period which is known to induce hepatic insulin resistance in global Nos3-deficient mice but not in wild-type C57Bl/6 mice. Surprisingly, we found that the absence of Nos3 in the bone marrow-derived component is associated with hepatic insulin resistance and that restoration of Nos3 in the bone marrow-derived component in global Nos3-deficient mice is sufficient to restore hepatic insulin sensitivity. Furthermore, we found that overexpression of Nos3 in bone marrow-derived component in wild-type mice attenuates the development of hepatic insulin resistance during high-fat feeding. Finally, compared with wild-type macrophages, the loss of macrophage Nos3 is associated with increased inflammatory responses to lipopolysaccharides and reduced anti-inflammatory responses to IL-4, a macrophage phenotype associated with the development of hepatic and systemic insulin resistance. CONCLUSIONS: These results would suggest that the metabolic and hepatic consequences of high-fat feeding are mediated by loss of Nos3/nitric oxide actions in bone marrow-derived cells, not in endothelial cells.
Assuntos
Glicemia/metabolismo , Metabolismo Energético , Resistência à Insulina , Fígado/enzimologia , Macrófagos/enzimologia , Óxido Nítrico Sintase Tipo III/metabolismo , Óxido Nítrico/metabolismo , Animais , Transplante de Medula Óssea , Dieta com Restrição de Gorduras , Dieta Hiperlipídica , Modelos Animais de Doenças , Células Endoteliais/enzimologia , Mediadores da Inflamação/metabolismo , Macrófagos/transplante , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Óxido Nítrico Sintase Tipo III/deficiência , Óxido Nítrico Sintase Tipo III/genéticaRESUMO
Cerebral amyloid angiopathy (CAA) is present in over half of the elderly population and in 80-90% of Alzheimer's disease (AD) patients. CAA is defined by the deposition of beta amyloid (Aß) in small cerebral arteries and capillaries. Cardiovascular risk factors are associated with an increased incidence of CAA. We utilized 18-month-old endothelial nitric oxide synthase (eNOS) heterozygous knockout (+/-) mice, a clinically relevant model of endothelial dysfunction, to examine the role of endothelial nitric oxide (NO) in vascular Aß accumulation. eNOS+/- mice had significantly higher vascular levels of Aß40 (P < 0.05). Aß42 was not detected. There was no difference in Aß in brain tissue. Amyloid precursor protein and ß-site APP cleavage enzyme 1 protein levels were unaltered, while levels of the α-secretase enzyme, a disintegrin and metalloproteinase 10, were significantly lower in eNOS + /- microvascular tissue (P < 0.05). Insulin degrading enzyme and low-density lipoprotein receptor-related protein 1 were significantly increased in eNOS+/- microvascular tissue, most likely an adaptive response to locally higher Aß concentrations. Lastly, catalase and CuZn superoxide dismutase were significantly elevated in eNOS+/- microvascular tissue (P < 0.05). These data demonstrate decreased availability of endothelial NO leads to increased cerebrovascular concentration of Aß along with compensatory mechanisms to protect the vasculature.
Assuntos
Doença de Alzheimer , Peptídeos beta-Amiloides/metabolismo , Encéfalo , Angiopatia Amiloide Cerebral , Endotélio Vascular , Óxido Nítrico Sintase Tipo III/deficiência , Fragmentos de Peptídeos/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/genética , Animais , Encéfalo/irrigação sanguínea , Encéfalo/metabolismo , Encéfalo/patologia , Angiopatia Amiloide Cerebral/genética , Angiopatia Amiloide Cerebral/metabolismo , Angiopatia Amiloide Cerebral/patologia , Endotélio Vascular/metabolismo , Endotélio Vascular/patologia , Camundongos , Camundongos Knockout , Óxido Nítrico/genética , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Fragmentos de Peptídeos/genéticaRESUMO
Three isoforms of nitric oxide synthase (NOS) occur in mammals. High levels of NO produced by NOS2/iNOS can protect against bacterial and parasitic infections, but the role of NOS in fungal innate immunity is less clear. Compared to wild type mice, Nos3-/- mice showed significantly higher survival of candidemia caused by Candida albicans SC5314. NOS3/eNOS is expressed by endothelial cells in the kidney, and colonization of this organ was decreased during the sub-acute stage of disseminated candidiasis. Nos3-/- mice more rapidly eliminated Candida from the renal cortex and exhibited more balanced local inflammatory reactions, with similar macrophage but less neutrophil infiltration than in infected wild type. Levels of the serum cytokines IL-9, IL-12, IL-17 and chemokines GM-CSF, MIP1α, and MIP1ß were significantly elevated, and IL-15 was significantly lower in infected Nos3-/- mice. Spleens of infected Nos3-/- mice had significantly more Th2 and Th9 but not other CD4+ T cells compared with wild type. Inflammatory genes associated with leukocyte chemotaxis, IL-1 signaling, TLR signaling and Th1 and Th2 cell differentiation pathways were significantly overexpressed in infected Nos3-/- kidneys, with Nos2 being the most strongly induced. Conversely, the general NOS inhibitor NG-nitro-L-arginine methyl ester increased virulence in the mouse candidemia model, suggesting that iNOS contributes to the protective mechanism in infected Nos3-/- mice. By moderating neutrophil infiltration, the absence of eNOS may reduce the collateral damage to kidney cortex, and Th-9 CD4+ cells may enhance clearance of the infection. These data suggest that selective eNOS inhibition could mitigate candidemia by a combination of systemic and local responses that promote a more effective host immune response.
Assuntos
Candida albicans/fisiologia , Candidíase/enzimologia , Candidíase/imunologia , Óxido Nítrico Sintase Tipo III/metabolismo , Animais , Candidíase/metabolismo , Citocinas/metabolismo , Deleção de Genes , Rim/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Infiltração de Neutrófilos , Óxido Nítrico Sintase Tipo II/metabolismo , Óxido Nítrico Sintase Tipo III/deficiência , Óxido Nítrico Sintase Tipo III/genética , Regulação para CimaRESUMO
BACKGROUND: The nitric oxide (NO)-producing activity of endothelial nitric oxide synthase (eNOS) plays a significant role in maintaining endothelial function and protecting against the stroke injury. However, the activity of the eNOS enzyme and the metabolism of major NO metabolite S-nitrosoglutathione (GSNO) are dysregulated after stroke, causing endothelial dysfunction. We investigated whether an administration of exogenous of GSNO or enhancing the level of endogenous GSNO protects against neurovascular injury in wild-type (WT) and eNOS-null (endothelial dysfunction) mouse models of cerebral ischemia-reperfusion (IR). METHODS: Transient cerebral ischemic injury was induced by middle cerebral artery occlusion (MCAO) for 60 minutes in male adult WT and eNOS null mice. GSNO (0.1 mg/kg body weight, intravenously) or N6022 (GSNO reductase inhibitor, 5.0 mg/kg body weight, intravenously) was administered 30 minutes before MCAO in preinjury and at the reperfusion in postinjury studies. Brain infarctions, edema, and neurobehavioral functions were evaluated at 24 hours after the reperfusion. RESULTS: eNOS-null mice had a higher degree (P< .05) of injury than WT. Pre- or postinjury treatment with either GSNO or N6022 significantly reduced infarct volume, improved neurological and sensorimotor function in both WT and eNOS-null mice. CONCLUSION: Reduced brain infarctions and edema, and improved neurobehavioral functions by pre- or postinjury GSNO treatment of eNOS knock out mice indicate that GSNO can attenuate IR injury, likely by mimicking the eNOS-derived NO-dependent anti-ischemic and anti-inflammatory functions. Neurovascular protection by GSNO/N6022 in both pre- and postischemic injury groups support GSNO as a promising drug candidate for the prevention and treatment of stroke injury.
Assuntos
Álcool Desidrogenase/antagonistas & inibidores , Benzamidas/farmacologia , Encéfalo/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Infarto da Artéria Cerebral Média/tratamento farmacológico , Fármacos Neuroprotetores/farmacologia , Óxido Nítrico Sintase Tipo III/metabolismo , Óxido Nítrico/metabolismo , Pirróis/farmacologia , S-Nitrosoglutationa/farmacologia , Álcool Desidrogenase/metabolismo , Animais , Comportamento Animal/efeitos dos fármacos , Encéfalo/embriologia , Encéfalo/patologia , Edema Encefálico/enzimologia , Edema Encefálico/patologia , Edema Encefálico/prevenção & controle , Modelos Animais de Doenças , Infarto da Artéria Cerebral Média/enzimologia , Infarto da Artéria Cerebral Média/genética , Infarto da Artéria Cerebral Média/patologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Óxido Nítrico Sintase Tipo III/deficiência , Óxido Nítrico Sintase Tipo III/genéticaRESUMO
BACKGROUND: Arteries chronically constricted in culture remodel to smaller diameters. Conversely, elevated luminal shear stress (SS) promotes outward remodeling of arteries in vivo and prevents inward remodeling in culture in a nitric oxide synthase (NOS)-dependent manner. OBJECTIVES: To determine whether SS-induced prevention of inward remodeling in cultured arteries is specifically eNOS-dependent and requires dilation, and whether SS alters the expression of eNOS and other genes potentially involved in remodeling. METHODS: Female mouse thoracodorsal arteries were cannulated, pressurized to 80 mm Hg, and cultured for 2 days with low SS (<7 dyn/cm2), high SS (≥15 dyn/cm2), high SS + L-NAME (NOS inhibitor, 10-4 M), or high SS in arteries from eNOS-/- mice. In separate arteries cultured 1 day with low or high SS, eNOS and connexin (Cx) 37, Cx40, and Cx43 mRNA were assessed with real-time PCR. RESULTS: High SS caused little change in passive diameters after culture (-4.7 ± 2.0%), which was less than low SS (-18.9 ± 1.4%; p < 0.0001), high SS eNOS-/- (-18.0 ± 1.5; p < 0.001), or high SS + L-NAME (-12.0 ± 0.6%; nonsignificant) despite similar constriction during culture. Cx37 mRNA expression was increased (p < 0.05) with high SS, but other gene levels were not different. CONCLUSIONS: eNOS is involved in SS-induced prevention of inward remodeling in cultured small arteries. This effect does not require NO-mediated dilation. SS increased Cx37.
Assuntos
Artérias/metabolismo , Conexinas/metabolismo , Hemodinâmica , Mecanotransdução Celular , Óxido Nítrico Sintase Tipo III/metabolismo , Remodelação Vascular , Animais , Artérias/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Feminino , Mecanotransdução Celular/efeitos dos fármacos , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Camundongos Knockout , Óxido Nítrico Sintase Tipo III/antagonistas & inibidores , Óxido Nítrico Sintase Tipo III/deficiência , Óxido Nítrico Sintase Tipo III/genética , Estresse Mecânico , Fatores de Tempo , Técnicas de Cultura de Tecidos , Remodelação Vascular/efeitos dos fármacos , Proteína alfa-4 de Junções ComunicantesRESUMO
Macrophage-mediated renal injury promotes the development of diabetic nephropathy. Blockade of chemokine (C-C motif) receptor 2 (CCR2) inhibits kidney macrophage accumulation and early glomerular damage in diabetic animals. This study tested early and late interventions with a CCR2 antagonist (CCR2A) in a model of progressive diabetic glomerulosclerosis and determined whether CCR2A provides added benefit over conventional treatment with an angiotensin-converting enzyme inhibitor (ACEi). Diabetes was induced in hypertensive endothelial nitric oxide synthase (Nos3)-deficient mice by administration of five low-dose streptozotocin (STZ) injections daily. Groups of diabetic Nos3-/- mice received a CCR2A (30 mg·kg-1·day-1 PF-04634817 in chow) as an early intervention (weeks 2-15 after STZ). The late intervention (weeks 8-15 after STZ) involved PF-04634817 alone, ACEi (captopril in water 10 mg·kg-1·day-1) alone, or combined ACEi + CCR2A. Control diabetic and nondiabetic Nos3-/- mice received normal chow and water. Early intervention with a CCR2A inhibited kidney inflammation and glomerulosclerosis, albuminuria, podocyte loss, and renal function impairment but not hypertension in diabetic Nos3-/- mice. Late intervention with a CCR2A also inhibited kidney inflammation, glomerulosclerosis, and renal dysfunction but did not affect albuminuria. ACEi alone suppressed hypertension and albuminuria and partially reduced podocyte loss and glomerulosclerosis but did not affect renal dysfunction. Compared with ACEi alone, the combined late intervention with ACEi + CCR2A provided better protection against kidney damage (inflammation, glomerulosclerosis, and renal function impairment) but not albuminuria. In conclusion, this study demonstrates that combining CCR2A and ACEi provides broader and superior renal protection than ACEi alone in a model of established diabetic glomerulosclerosis with hypertension.
Assuntos
Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Nefropatias Diabéticas/prevenção & controle , Óxido Nítrico Sintase Tipo III/genética , Receptores CCR2/antagonistas & inibidores , Albuminúria/prevenção & controle , Animais , Compostos Azabicíclicos/uso terapêutico , Captopril/uso terapêutico , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/tratamento farmacológico , Nefropatias Diabéticas/patologia , Progressão da Doença , Hipertensão Renal/etiologia , Hipertensão Renal/prevenção & controle , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Óxido Nítrico Sintase Tipo III/deficiência , Podócitos/patologia , Pirimidinas/uso terapêuticoRESUMO
Clinical studies indicate that sex differences exist in susceptibility for developing diabetic kidney disease (DKD), supporting the need to examine both sexes in animal studies of DKD. Streptozotocin (STZ) is commonly used in male mice to induce diabetes and DKD. However, females are not normally included because their sex hormones partially protect them from STZ-induced islet injury and consequent diabetes. To address this issue, we identified a strategy to induce comparable diabetes in male and female mice using STZ and determined whether both sexes develop equivalent renal injury. Male and female mice lacking the gene for endothelial nitric oxide synthase (Nos3-/-) were made diabetic with five or six low-dose STZ injections, respectively. Groups of male and female mice with equivalent hyperglycemia at week 3 after STZ were assessed for DKD at week 8. STZ-treated male and female Nos3-/- mice maintained comparable hyperglycemia between weeks 3 and 8 had an equivalent increase in HbA1c levels and comparable hypertension. Urine albumin/creatinine levels were elevated eightfold in mice of both sexes at week 8, accompanied by an equivalent loss of podocytes. In diabetic males and females, plasma cystatin C levels and glomerular collagen deposition were similarly increased. Kidney mRNA levels of proinflammatory and profibrotic markers and kidney injury molecule-1 (KIM-1) were equally elevated in males and females, indicating comparable kidney injury. This study shows that equivalent diabetes induces a comparable onset of DKD in male and female Nos3-/- mice, demonstrating that it is possible to include males and females together in studies of DKD.
Assuntos
Diabetes Mellitus Experimental/fisiopatologia , Nefropatias Diabéticas/fisiopatologia , Óxido Nítrico Sintase Tipo III/deficiência , Caracteres Sexuais , Albuminúria/induzido quimicamente , Albuminúria/fisiopatologia , Animais , Glicemia/metabolismo , Peso Corporal/fisiologia , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/patologia , Nefropatias Diabéticas/sangue , Nefropatias Diabéticas/induzido quimicamente , Nefropatias Diabéticas/patologia , Suscetibilidade a Doenças , Feminino , Regulação da Expressão Gênica/fisiologia , Hemoglobinas Glicadas/metabolismo , Hipertensão/fisiopatologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fatores Sexuais , EstreptozocinaRESUMO
Endothelial dysfunction has been linked to vascular inflammation and foam cell formation but the underlying mechanisms still remain unclear. We sought to define the factors inducing inflammation and smooth muscle foam cell formation under endothelial dysfunction using endothelial nitric oxide synthase (eNOS)-deficient mice. Vascular smooth muscle cells (VSMCs) from eNOS-deficient mice displayed increased expression of macrophage-related genes and elevated lipid uptake. Neuropeptide Y (NPY) was upregulated in the aorta from the eNOS-deficient mice and promoted macrophage chemotaxis toward VSMCs while enhancing the activity of matrix metalloproteinase-3. Notably, NPY induced lipid uptake in VSMCs, facilitating smooth muscle foam cell formation, in association with enhanced expression of genes related to modified low-density lipoprotein uptake and macrophages. NPY was augmented by inflammatory pentraxin 3 (PTX3) in VSMCs. PTX3 enhanced macrophage migratory capacity through the NPY/neuropeptide Y receptor axis and this effect was attenuated by pharmacological inhibition with a receptor-specific antagonist. These observations suggest that endothelial dysfunction leads to the elevation of NPY that amplifies vascular inflammation by increasing inflammatory cell chemotaxis and triggers smooth muscle foam cell formation.