RESUMO
BACKGROUND: Mechanical stress on the heart, such as high blood pressure, initiates inflammation and causes hypertrophic heart disease. However, the regulatory mechanism of inflammation and its role in the stressed heart remain unclear. IL-1ß (interleukin-1ß) is a proinflammatory cytokine that causes cardiac hypertrophy and heart failure. Here, we show that neural signals activate the NLRP3 (nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing 3) inflammasome for IL-1ß production to induce adaptive hypertrophy in the stressed heart. METHODS: C57BL/6 mice, knockout mouse strains for NLRP3 and P2RX7 (P2X purinoceptor 7), and adrenergic neuron-specific knockout mice for SLC17A9, a secretory vesicle protein responsible for the storage and release of ATP, were used for analysis. Pressure overload was induced by transverse aortic constriction. Various animal models were used, including pharmacological treatment with apyrase, lipopolysaccharide, 2'(3')-O-(4-benzoylbenzoyl)-ATP, MCC950, anti-IL-1ß antibodies, clonidine, pseudoephedrine, isoproterenol, and bisoprolol, left stellate ganglionectomy, and ablation of cardiac afferent nerves with capsaicin. Cardiac function and morphology, gene expression, myocardial IL-1ß and caspase-1 activity, and extracellular ATP level were assessed. In vitro experiments were performed using primary cardiomyocytes and fibroblasts from rat neonates and human microvascular endothelial cell line. Cell surface area and proliferation were assessed. RESULTS: Genetic disruption of NLRP3 resulted in significant loss of IL-1ß production, cardiac hypertrophy, and contractile function during pressure overload. A bone marrow transplantation experiment revealed an essential role of NLRP3 in cardiac nonimmune cells in myocardial IL-1ß production and cardiac phenotype. Pharmacological depletion of extracellular ATP or genetic disruption of the P2X7 receptor suppressed myocardial NLRP3 inflammasome activity during pressure overload, indicating an important role of ATP/P2X7 axis in cardiac inflammation and hypertrophy. Extracellular ATP induced hypertrophic changes of cardiac cells in an NLRP3- and IL-1ß-dependent manner in vitro. Manipulation of the sympathetic nervous system suggested sympathetic efferent nerves as the main source of extracellular ATP. Depletion of ATP release from sympathetic efferent nerves, ablation of cardiac afferent nerves, or a lipophilic ß-blocker reduced cardiac extracellular ATP level, and inhibited NLRP3 inflammasome activation, IL-1ß production, and adaptive cardiac hypertrophy during pressure overload. CONCLUSIONS: Cardiac inflammation and hypertrophy are regulated by heart-brain interaction. Controlling neural signals might be important for the treatment of hypertensive heart disease.
Assuntos
Inflamassomos , Proteínas de Transporte de Nucleotídeos , Camundongos , Ratos , Humanos , Animais , Inflamassomos/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Camundongos Endogâmicos C57BL , Miócitos Cardíacos/metabolismo , Inflamação , Arritmias Cardíacas , Encéfalo/metabolismo , Cardiomegalia , Trifosfato de Adenosina/metabolismo , Interleucina-1beta/metabolismo , Proteínas de Transporte de Nucleotídeos/metabolismoRESUMO
AIMS: Lifestyle-related diseases promote atherosclerosis, a chronic inflammatory disease; however, the molecular mechanism remains largely unknown. Endogenous DNA fragments released under over-nutrient condition provoke sterile inflammation through the recognition by DNA sensors. Here, we investigated the role of stimulator of interferon genes (STING), a cytosolic DNA sensor, in atherogenesis. METHODS AND RESULTS: Apolipoprotein E-deficient (Apoe-/-) mice fed a western-type diet (WTD), a hypercholesterolaemic mouse model, showed higher STING expression and markers for DNA damage such as γH2AX, p53, and single-stranded DNA (ssDNA) accumulation in macrophages in the aorta compared with wild-type (WT) mice. The level of cGAMP, a STING agonist, in the aorta was higher in Apoe-/- mice. Genetic deletion of Sting in Apoe-/- mice reduced atherosclerotic lesions in the aortic arch, lipid, and macrophage accumulation in plaques, and inflammatory molecule expression in the aorta compared with the control. Pharmacological blockade of STING using a specific inhibitor, C-176, ameliorated atherogenesis in Apoe-/- mice. In contrast, bone marrow-specific STING expression in Apoe-/- mice stimulated atherogenesis. Expression or deletion of STING did not affect metabolic parameters and blood pressure. In vitro studies revealed that STING activation by cGAMP or mitochondrial DNA accelerated inflammatory molecule expression (e.g. TNF-α or IFN-ß) in mouse and human macrophages. Activation of nuclear factor-κB and TANK binding kinase 1 was involved in STING-associated vascular inflammation and macrophage activation. Furthermore, human atherosclerotic lesions in the carotid arteries expressed STING and cGAMP. CONCLUSION: Stimulator of interferon genes stimulates pro-inflammatory activation of macrophages, leading to the development of atherosclerosis. Stimulator of interferon genes signalling may serve as a potential therapeutic target for atherosclerosis.
Assuntos
Aterosclerose , Placa Aterosclerótica , Animais , Aterosclerose/genética , DNA , Modelos Animais de Doenças , Imunidade Inata , Inflamação , Estilo de Vida , Camundongos , Camundongos Endogâmicos C57BL , Camundongos KnockoutRESUMO
Adipose tissue serves not only as an energy store or a mechanical cushion, but also as an endocrine organ. Recent evidence revealed that perivascular adipose tissue is involved in vascular homeostasis and pathophysiology of adjacent arteries by producing various adipokines. Epicardial adipose tissue (EAT) is located between the surface of the heart and the visceral layer of the pericardium and surrounds the coronary arteries. Many clinical studies suggest that an increase in EAT volume is associated with coronary artery disease. It has been reported that exercise and some antidiabetic drugs can reduce EAT volume. In this review, we outline recent findings on the roles of EAT in the pathogenesis of coronary atherosclerosis.
Assuntos
Tecido Adiposo/fisiopatologia , Doença da Artéria Coronariana , Adipocinas , Doença da Artéria Coronariana/etiologia , Doença da Artéria Coronariana/fisiopatologia , Humanos , PericárdioRESUMO
Rheumatoid arthritis (RA) is a chronic polyarthritis of unknown etiology. To unravel the molecular mechanisms in RA, we performed targeted DNA sequencing analysis of patients with RA. This analysis identified a variant of the death receptor 3 (DR3) gene, a member of the family of apoptosis-inducing Fas genes, which contains four single-nucleotide polymorphisms (SNPs) and a 14-nucleotide deletion within exon 5 and intron 5. We found that the deletion causes the binding of splicing regulatory proteins to DR3 pre-mRNA intron 5, resulting in a portion of intron 5 becoming part of the coding sequence, thereby generating a premature stop codon. We also found that this truncated DR3 protein product lacks the death domain and forms a heterotrimer complex with wildtype DR3 that dominant-negatively inhibits ligand-induced apoptosis in lymphocytes. Myelocytes from transgenic mice expressing the human DR3 variant produced soluble truncated DR3, forming a complex with TNF-like ligand 1A (TL1A), which inhibited apoptosis induction. In summary, our results reveal that a DR3 splice variant that interferes with ligand-induced T cell responses and apoptosis may contribute to RA pathogenesis.
Assuntos
Apoptose , Artrite Reumatoide/fisiopatologia , Membro 25 de Receptores de Fatores de Necrose Tumoral/genética , Membro 25 de Receptores de Fatores de Necrose Tumoral/metabolismo , Linfócitos T/citologia , Animais , Éxons , Humanos , Íntrons , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Polimorfismo de Nucleotídeo Único , Domínios Proteicos , Membro 25 de Receptores de Fatores de Necrose Tumoral/química , Transdução de Sinais , Linfócitos T/metabolismo , Membro 15 da Superfamília de Ligantes de Fatores de Necrose Tumoral/genética , Membro 15 da Superfamília de Ligantes de Fatores de Necrose Tumoral/metabolismoRESUMO
Although pleural thickening is a common finding on routine chest X-rays, its radiological and clinical features remain poorly characterized. Our investigation of 28,727 chest X-rays obtained from annual health examinations confirmed that pleural thickening was the most common abnormal radiological finding. In most cases (92.2%), pleural thickening involved the apex of the lung, particularly on the right side; thus, it was defined as a pulmonary apical cap. Pleural thickening was more common in males than in females and in current smokers or ex-smokers than in never smokers. The prevalence increased with age, ranging from 1.8% in teenagers to 9.8% in adults aged 60 years and older. Moreover, pleural thickening was clearly associated with greater height and lower body weight and body mass index, suggesting that a tall, thin body shape may predispose to pleural thickening. These observations allowed us to speculate about the causative mechanisms of pleural thickening that are attributable to disproportionate perfusion, ventilation, or mechanical forces in the lungs.
Assuntos
Radiografia Pulmonar de Massa/métodos , Pleura/diagnóstico por imagem , Doenças Pleurais/diagnóstico por imagem , Doenças Pleurais/epidemiologia , Tomografia Computadorizada por Raios X/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Feminino , Humanos , Masculino , Radiografia Pulmonar de Massa/normas , Pessoa de Meia-Idade , Tomografia Computadorizada por Raios X/normas , Adulto JovemRESUMO
Dipeptidyl peptidase-4 (DPP-4) inhibitors are novel antidiabetic agents with possible vascular protection effects. Endothelial dysfunction is an initiation step in atherogenesis. The purpose of this study was to investigate whether vildagliptin (Vilda) attenuates the development of endothelial dysfunction and atherosclerotic lesions in nondiabetic apolipoprotein E-deficient (ApoE-/-) mice. Eight-week-old nondiabetic ApoE-/- mice fed a Western-type diet received Vilda (50 mg/kg/day) for 20 weeks or 8 weeks. After 20 weeks of treatment, Vilda administration reduced atherogenesis in the aortic arch as determined by en face Sudan IV staining compared with the vehicle group (P < 0.05). Vilda also reduced lipid accumulation (P < 0.05) and vascular cell adhesion molecule-1 (VCAM-1) expression (P < 0.05) and tended to decrease macrophage infiltration (P = 0.05) into atherosclerotic plaques compared with vehicle. After 8 weeks of treatment, endothelium-dependent vascular reactivity was examined. Vilda administration significantly attenuated the impairment of endothelial function in nondiabetic ApoE-/- mice compared with the vehicle group (P < 0.05). Vilda treatment did not alter metabolic parameters, including blood glucose level, in both study protocols. To investigate the mechanism, aortic segments obtained from wild-type mice were incubated with exendin-4 (Ex-4), a glucagon-like peptide-1 (GLP-1) analog, in the presence or absence of lipopolysaccharide (LPS). Ex-4 attenuated the impairment of endothelium-dependent vasodilation induced by LPS (P < 0.01). Furthermore, Ex-4 promoted phosphorylation of eNOS at Ser1177 which was decreased by LPS in human umbilical endothelial cells (P < 0.05). Vilda inhibited the development of endothelial dysfunction and prevented atherogenesis in nondiabetic ApoE-/- mice. Our results suggested that GLP-1-dependent amelioration of endothelial dysfunction is associated with the atheroprotective effects of Vilda.
Assuntos
Aterosclerose/prevenção & controle , Inibidores da Dipeptidil Peptidase IV/uso terapêutico , Células Endoteliais/efeitos dos fármacos , Endotélio Vascular/efeitos dos fármacos , Vildagliptina/uso terapêutico , Animais , Apolipoproteínas E , Aterosclerose/etiologia , Aterosclerose/patologia , Técnicas de Cultura de Células , Modelos Animais de Doenças , Células Endoteliais/fisiologia , Endotélio Vascular/patologia , Camundongos , Camundongos Endogâmicos C57BL , Molécula 1 de Adesão de Célula Vascular/sangueRESUMO
Seizures are increasingly being recognized as the hallmark of Alzheimer's disease (AD). Neuronal hyperactivity can be a consequence of neuronal damage caused by abnormal amyloid ß (Aß) depositions. However, it can also be a cell-autonomous phenomenon causing AD by Aß-independent mechanisms. Various studies using animal models have shown that Ca2+ is released from the endoplasmic reticulum (ER) via type 1 inositol triphosphate receptors (InsP3R1s) and ryanodine receptors (RyRs). To investigate which is the main pathophysiological mechanism in human neurons, we measured Ca2+ signaling in neural cells derived from three early-onset AD patients harboring Presenilin-1 variants (PSEN1 p.A246E, p.L286V, and p.M146L). Of these, it has been reported that PSEN1 p.A246E and p.L286V did not produce a significant amount of abnormal Aß. We found all PSEN1-mutant neurons, but not wild-type, caused abnormal Ca2+-bursts in a manner dependent on the calcium channel, Ryanodine Receptor 2 (RyR2). Indeed, carvedilol, an RyR2 inhibitor, and VK-II-86, an analog of carvedilol without the ß-blocking effects, sufficiently eliminated the abnormal Ca2+ bursts. In contrast, Dantrolene, an inhibitor of RyR1 and RyR3, and Xestospongin c, an IP3R inhibitor, did not attenuate the Ca2+-bursts. The Western blotting showed that RyR2 expression was not affected by PSEN1 p.A246E, suggesting that the variant may activate the RyR2. The RNA-Seq data revealed that ER-stress responsive genes were increased, and mitochondrial Ca2+-transporter genes were decreased in PSEN1A246E cells compared to the WT neurons. Thus, we propose that aberrant Ca2+ signaling is a key link between human pathogenic PSEN1 variants and cell-intrinsic hyperactivity prior to deposition of abnormal Aß, offering prospects for the development of targeted prevention strategies for at-risk individuals.
Assuntos
Doença de Alzheimer , Sinalização do Cálcio , Cálcio , Carvedilol , Neurônios , Presenilina-1 , Canal de Liberação de Cálcio do Receptor de Rianodina , Feminino , Humanos , Masculino , Doença de Alzheimer/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Cálcio/metabolismo , Sinalização do Cálcio/efeitos dos fármacos , Retículo Endoplasmático/metabolismo , Retículo Endoplasmático/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/efeitos dos fármacos , Presenilina-1/genética , Presenilina-1/metabolismo , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Canal de Liberação de Cálcio do Receptor de Rianodina/genética , Carvedilol/farmacologiaRESUMO
OBJECTIVE: ATP-binding cassette transporter subfamily G member 2 (ABCG2), expressed in microvascular endothelial cells in the heart, has been suggested to regulate several tissue defense mechanisms. This study was performed to elucidate its role in pressure overload-induced cardiac hypertrophy. METHODS AND RESULTS: Pressure overload was induced in 8- to 12-week-old wild-type and Abcg2-/- mice by transverse aortic constriction (TAC). Abcg2-/- mice showed exaggerated cardiac hypertrophy and ventricular remodeling after TAC compared with wild-type mice. In the early phase after TAC, functional impairment in angiogenesis and antioxidant response in myocardium was found in Abcg2-/- mice. In vitro experiments demonstrated that ABCG2 regulates transport of glutathione, an important endogenous antioxidant, from microvascular endothelial cells. Besides, glutathione transported from microvascular endothelial cells in ABCG2-dependent manner ameliorated oxidative stress-induced cardiomyocyte hypertrophy. In vivo, glutathione levels in plasma and the heart were increased in wild-type mice but not in Abcg2-/- mice after TAC. Treatment with the superoxide dismutase mimetic ameliorated cardiac hypertrophy in Abcg2-/- mice after TAC to the same extent as that in wild-type mice, although cardiac dysfunction with impaired angiogenesis was observed in Abcg2-/- mice. CONCLUSION: ABCG2 protects against pressure overload-induced cardiac hypertrophy and heart failure by promoting angiogenesis and antioxidant response.
Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Antioxidantes/metabolismo , Células Endoteliais/metabolismo , Glutationa/metabolismo , Insuficiência Cardíaca/prevenção & controle , Hipertrofia Ventricular Esquerda/prevenção & controle , Miócitos Cardíacos/metabolismo , Proteínas de Neoplasias/metabolismo , Neovascularização Fisiológica , Estresse Oxidativo , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Transportadores de Cassetes de Ligação de ATP/genética , Animais , Animais Recém-Nascidos , Antioxidantes/farmacologia , Células Cultivadas , Modelos Animais de Doenças , Células Endoteliais/efeitos dos fármacos , Genótipo , Glutationa/sangue , Insuficiência Cardíaca/genética , Insuficiência Cardíaca/metabolismo , Insuficiência Cardíaca/fisiopatologia , Membro Posterior , Humanos , Hipertrofia Ventricular Esquerda/genética , Hipertrofia Ventricular Esquerda/metabolismo , Hipertrofia Ventricular Esquerda/fisiopatologia , Isquemia/genética , Isquemia/metabolismo , Isquemia/fisiopatologia , Masculino , Camundongos , Camundongos Knockout , Músculo Esquelético/irrigação sanguínea , Miócitos Cardíacos/efeitos dos fármacos , Proteínas de Neoplasias/genética , Estresse Oxidativo/efeitos dos fármacos , Fenótipo , Interferência de RNA , Ratos , Ratos Wistar , Fatores de Tempo , Transfecção , Função Ventricular , Remodelação VentricularRESUMO
Our previous study has demonstrated that testosterone rapidly activates endothelial nitric oxide synthase (eNOS), enhancing nitric oxide (NO) release from endothelial cells (ECs) via the phosphatidylinositol 3-kinase/Akt (PI3-kinase/Akt) pathway. The upstream regulators of this pathway are unknown. In this study, we further investigated the non-genomic action of testosterone in human aortic ECs. Acute (30 min) activation of eNOS caused by testosterone was unaffected by pretreatment with a transcriptional inhibitor, actinomycin D. Non-permeable testosterone-BSA rapidly induced Akt and eNOS phosphorylation. In contrast, luciferase reporter assay showed that the transcriptional activity of the androgen-responsive element (ARE) was increased by testosterone, but not by testosterone-BSA at 2h after stimulation. Immunostaining displayed co-localization of androgen receptor (AR) with caveolin-1. Fractional analysis showed that AR was expressed in caveolae-enriched membrane fractions. Immunoprecipitation assays revealed the association of AR with caveolin-1 and c-Src, suggesting complex formation among them. Testosterone rapidly increased the phosphorylation of c-Src on Tyr416, which was inhibited by an AR antagonist and by siRNA for AR. PP2, a specific-inhibitor of Src kinase, abolished the testosterone-induced phosphorylation of Akt and eNOS. Our data indicate that testosterone induces rapid assembly of a membrane signaling complex among AR, caveolin-1 and c-Src, which then facilitates activation of the c-Src/ PI3-kinase/Akt cascade, resulting in activation of eNOS.
Assuntos
Endotélio Vascular/enzimologia , Óxido Nítrico Sintase Tipo III/biossíntese , Receptores Androgênicos/metabolismo , Testosterona/fisiologia , Quinases da Família src/metabolismo , Cavéolas/metabolismo , Caveolina 1/metabolismo , Células Cultivadas , Endotélio Vascular/efeitos dos fármacos , Ativação Enzimática , Humanos , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , Testosterona/farmacologia , Transcrição Gênica/efeitos dos fármacosRESUMO
OBJECTIVE: To clarify the impact of breast cancer resistance protein 1 (BCRP1)/ATP-binding cassette transporter subfamily G member 2 (ABCG2) expression on cardiac repair after myocardial infarction (MI). METHODS AND RESULTS: The ATP-binding cassette transporter BCRP1/ABCG2 is expressed in various organs, including the heart, and may regulate several tissue defense mechanisms. BCRP1/ABCG2 was mainly expressed in endothelial cells of microvessels in the heart. MI was induced in 8- to 12-week-old wild-type (WT) and Bcrp1/Abcg2 knockout (KO) mice by ligating the left anterior descending artery. At 28 days after MI, the survival rate was significantly lower in KO mice than in WT mice because of cardiac rupture. Echocardiographic, hemodynamic, and histological assessments showed that ventricular remodeling was more deteriorated in KO than in WT mice. Capillary, myofibroblast, and macrophage densities in the peri-infarction area at 5 days after MI were significantly reduced in KO compared with WT mice. In vitro experiments demonstrated that inhibition of BCRP1/ABCG2 resulted in accumulation of intracellular protoporphyrin IX and impaired survival of microvascular endothelial cells under oxidative stress. Moreover, BCRP1/ABCG2 inhibition impaired migration and tube formation of endothelial cells. CONCLUSIONS: BCRP1/ABCG2 plays a pivotal role in cardiac repair after MI via modulation of microvascular endothelial cell survival and function.
Assuntos
Transportadores de Cassetes de Ligação de ATP/fisiologia , Células Endoteliais/fisiologia , Microvasos/fisiopatologia , Infarto do Miocárdio/fisiopatologia , Proteínas de Neoplasias/fisiologia , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Animais , Sobrevivência Celular , Feminino , Camundongos , Camundongos Knockout , Recuperação de Função Fisiológica , CicatrizaçãoRESUMO
Silk fibroin fiber has a long history of use in sutures because of its high strength and toughness. In the work reported in this paper, small-diameter vascular grafts 1.5 mm in diameter and 10 mm in length were prepared by coating a double-raschel knitted silk fiber graft with silk fibroin aqueous solution containing poly(ethylene glycol diglycidyl ether) as a cross-linking agent. The most important character of silk fibroin graft is remodeling, which is never observed for polyester fiber or expanded polytetrafluoroethylene grafts. The double-raschel knitted silk fiber graft with coating has sufficient physical strength and protects the ladder from the end in the implantation process. The coating also gives protection against leakage of blood from the graft, and elasticity to the graft. Eight weeks after implantation of the grafts in rat abdominal aorta, early formation of thrombosis was avoided.
Assuntos
Aorta Abdominal/cirurgia , Prótese Vascular , Enxerto Vascular/instrumentação , Animais , Masculino , Ratos , Ratos Sprague-Dawley , SedaAssuntos
Túnica Adventícia/irrigação sanguínea , Estenose Coronária/cirurgia , Vasos Coronários/fisiopatologia , Everolimo/uso terapêutico , Neovascularização Fisiológica , Implantação de Prótese , Sirolimo/análogos & derivados , Stents , Tomografia de Coerência Óptica/métodos , Vasa Vasorum/fisiopatologia , Animais , Feminino , Humanos , Masculino , Sirolimo/farmacologiaRESUMO
AIM: Synthetic vascular grafts are widely used in surgical revascularization, mainly for medium- to large-sized vessels. However, synthetic grafts smaller than 6 mm in diameter are associated with a high incidence of thrombosis. In this study, we evaluated silk fibroin, a major protein of silk, with high biocompatibility and biodegradability, as a useful material for extremely-small-diameter vascular grafts. METHODS: A small-sized (0.9 mm inner diameter) graft was braided from a silk fibroin thread. The right carotid arteries of 8- to 14-week-old male C57BL/6 mice were cut at the midpoint, and fibroin grafts (5- to 7-mm in length) were transplanted using a cuff technique with polyimide cuffs. The grafts were harvested at different time points and analyzed histologically. RESULTS: CD31ï¼ endothelial cells had already started to proliferate at 2 weeks after implantation. At 4 weeks, neointima had formed with α-smooth muscle actin+ cells, and the luminal surface was covered with CD31ï¼endothelial cells. Mac3ï¼ macrophages were accumulated in the grafts. Graft patency was confirmed at up to 6 months after implantation. CONCLUSION: This mouse model of arterial graft implantation enables us to analyze the remodeling process and biocompatibility of extremely-small-diameter vascular grafts. Biodegradable silk fibroin might be applicable for further researches using genetically modified mice.
Assuntos
Implantes Absorvíveis , Materiais Biocompatíveis/química , Prótese Vascular , Fibroínas/química , Animais , Implante de Prótese Vascular , Proliferação de Células , Células Endoteliais/citologia , Masculino , Camundongos Endogâmicos C57BL , Grau de Desobstrução VascularRESUMO
Recent evidence suggests that bone marrow-derived cells may contribute to repair and lesion formation following vascular injury. In most studies, bone marrow-derived cells were tracked by transplanting exogenous cells into bone marrow that had been compromised by irradiation. It remains to be determined whether endogenous circulating progenitors actually contribute to arterial remodeling under physiological conditions. Here, we established a parabiotic model in which two mice were conjoined subcutaneously without any vascular anastomosis. When wild-type mice were joined with transgenic mice that expressed green fluorescent protein (GFP) in all tissues, GFP-positive cells were detected not only in the peripheral blood but also in the bone marrow of the wild-type mice. The femoral arteries of the wild-type mice were mechanically injured by insertion of a large wire. At 4 wk, there was neointima hyperplasia that mainly consisted of alpha-smooth muscle actin-positive cells. GFP-positive cells were readily detected in the neointima (14.8+/-4.5%) and media (31.1+/-8.8%) of the injured artery. Some GFP-positive cells expressed alpha-smooth muscle actin or an endothelial cell marker. These results indicate that circulating progenitors contribute to re-endothelialization and neointimal formation after mechanical vascular injury even in nonirradiated mice.
Assuntos
Movimento Celular , Células-Tronco/citologia , Actinas/metabolismo , Animais , Transplante de Medula Óssea , Genes Reporter/genética , Hiperplasia/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Microscopia Imunoeletrônica , Parabiose , Células-Tronco/metabolismo , Células-Tronco/efeitos da radiaçãoAssuntos
Carbono-Nitrogênio Ligases/antagonistas & inibidores , Lesões das Artérias Carótidas/prevenção & controle , Citidina/análogos & derivados , Inibidores Enzimáticos/farmacologia , Terapia Genética , Terapia de Alvo Molecular , Músculo Liso Vascular/efeitos dos fármacos , Miócitos de Músculo Liso/efeitos dos fármacos , Lesões do Sistema Vascular/prevenção & controle , Animais , Citidina/farmacologia , MasculinoRESUMO
Background Toll-like receptor ( TLR ) 9 recognizes bacterial DNA , activating innate immunity, whereas it also provokes inflammation in response to fragmented DNA released from mammalian cells. We investigated whether TLR 9 contributes to the development of vascular inflammation and atherogenesis using apolipoprotein E-deficient ( Apoe -/-) mice. Methods and Results Tlr9-deficient Apoe -/- ( Tlr9 -/- Apoe -/-) mice and Apoe -/- mice on a Western-type diet received subcutaneous angiotensin II infusion (1000 ng/kg per minute) for 28 days. Angiotensin II increased the plasma level of double-stranded DNA, an endogenous ligand of TLR 9, in these mice. Genetic deletion or pharmacologic blockade of TLR 9 in angiotensin II-infused Apoe -/- mice attenuated atherogenesis in the aortic arch ( P<0.05), reduced the accumulation of lipid and macrophages in atherosclerotic plaques, and decreased RNA expression of inflammatory molecules in the aorta with no alteration of metabolic parameters. On the other hand, restoration of TLR 9 in bone marrow in Tlr9 -/- Apoe -/- mice promoted atherogenesis in the aortic arch ( P<0.05). A TLR 9 agonist markedly promoted proinflammatory activation of Apoe -/- macrophages, partially through p38 mitogen-activated protein kinase signaling. In addition, genomic DNA extracted from macrophages promoted inflammatory molecule expression more effectively in Apoe -/- macrophages than in Tlr9 -/- Apoe -/- macrophages. Furthermore, in humans, circulating double-stranded DNA in the coronary artery positively correlated with inflammatory features of coronary plaques determined by optical coherence tomography in patients with acute myocardial infarction ( P<0.05). Conclusions TLR 9 plays a pivotal role in the development of vascular inflammation and atherogenesis through proinflammatory activation of macrophages. TLR 9 may serve as a potential therapeutic target for atherosclerosis.
Assuntos
Aterosclerose/genética , Ácidos Nucleicos Livres/imunologia , Inflamação/imunologia , Macrófagos/imunologia , Placa Aterosclerótica/genética , Receptor Toll-Like 9/genética , Idoso , Angiotensina II/toxicidade , Animais , Aorta Torácica/patologia , Aterosclerose/induzido quimicamente , Aterosclerose/imunologia , Aterosclerose/patologia , Transplante de Medula Óssea , Ácidos Nucleicos Livres/sangue , Quimiocina CCL2/genética , Quimiocina CCL2/imunologia , Feminino , Humanos , Técnicas In Vitro , Inflamação/genética , Lipídeos , Macrófagos/patologia , Macrófagos Peritoneais/imunologia , Masculino , Camundongos , Camundongos Knockout , Camundongos Knockout para ApoE , Microscopia Eletrônica , Infarto do Miocárdio/sangue , Infarto do Miocárdio/terapia , Intervenção Coronária Percutânea , Placa Aterosclerótica/imunologia , Placa Aterosclerótica/patologia , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Receptor Toll-Like 9/antagonistas & inibidores , Receptor Toll-Like 9/imunologia , Tomografia de Coerência Óptica , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/imunologia , Vasoconstritores/toxicidadeAssuntos
Aterosclerose/etiologia , Vasos Sanguíneos/patologia , Animais , Aterosclerose/genética , Aterosclerose/fisiopatologia , Aterosclerose/terapia , Células da Medula Óssea/metabolismo , Células da Medula Óssea/patologia , Humanos , Metabolismo dos Lipídeos , Neovascularização Patológica/genética , Sistema Renina-Angiotensina/genéticaRESUMO
Traditionally, it is believed that white adipose tissues serve as energy storage, heat insulation, and mechanical cushion, whereas non-shivering thermogenesis occurs in brown adipose tissue. Recent evidence revealed that adipose tissue secretes many types of cytokines, called as adipocytokines, which modulate glucose metabolism, lipid profile, appetite, fibrinolysis, blood pressure, and inflammation. Most of the arteries are surrounded by perivascular adipose tissue (PVAT). PVAT has been thought to be simply a structurally supportive tissue for vasculature. However, recent studies showed that PVAT influences vasodilation and vasocontraction, suggesting that PVAT regulates vascular tone and diameter. Adipocytokines secreted from PVAT appear to have direct access to the adjacent arterial wall by diffusion or via vasa vasorum. In fact, PVAT around atherosclerotic lesions and mechanically-injured arteries displayed inflammatory cytokine profiles, suggesting that PVAT functions to promote vascular lesion formation. Many clinical studies revealed that increased accumulation of epicardial adipose tissue (EAT), which surrounds coronary arteries, is associated with coronary artery disease. In this review article, we will summarize recent findings about potential roles of PVAT in the pathogenesis of atherosclerosis, particularly focusing on a series of basic and clinical studies from our laboratory.
RESUMO
Accumulating evidence suggests that activated factor X (FXa), a key coagulation factor, plays an important role in the development of vascular inflammation through activation of many cell types. Here, we investigated whether pharmacological blockade of FXa attenuates neointima formation after wire-mediated vascular injury. Transluminal femoral artery injury was induced in C57BL/6 mice by inserting a straight wire. Rivaroxaban (5mg/kg/day), a direct FXa inhibitor, was administered from one week before surgery until killed. At four weeks after surgery, rivaroxaban significantly attenuated neointima formation in the injured arteries compared with control (P<0.01). Plasma lipid levels and blood pressure were similar between the rivaroxaban-treated group and non-treated group. Quantitative RT-PCR analyses demonstrated that rivaroxaban reduced the expression of inflammatory molecules (e.g., IL-1ß and TNF-α) in injured arteries at seven days after surgery (P<0.05, respectively). In vitro experiments using mouse peritoneal macrophages demonstrated that FXa increased the expression of inflammatory molecules (e.g., IL-1ß and TNF-α), which was blocked in the presence of rivaroxaban (P<0.05). Also, in vitro experiments using rat vascular smooth muscle cells (VSMC) demonstrated that FXa promoted both proliferation and migration of this cell type (P<0.05), which were blocked in the presence of rivaroxaban. Inhibition of FXa by rivaroxaban attenuates neointima formation after wire-mediated vascular injury through inhibition of inflammatory activation of macrophages and VSMC.
Assuntos
Inibidores do Fator Xa/farmacologia , Fator Xa/metabolismo , Neointima/tratamento farmacológico , Rivaroxabana/farmacologia , Lesões do Sistema Vascular/patologia , Animais , Inibidores do Fator Xa/uso terapêutico , Regulação da Expressão Gênica/efeitos dos fármacos , Hiperplasia/tratamento farmacológico , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neointima/imunologia , Neointima/metabolismo , Rivaroxabana/uso terapêutico , Transdução de Sinais/efeitos dos fármacosRESUMO
BACKGROUND AND AIMS: Ticagrelor reduces cardiovascular events in patients with acute coronary syndrome (ACS). Recent studies demonstrated the expression of P2Y12 on vascular cells including endothelial cells, as well as platelets, and suggested its contribution to atherogenesis. We investigated whether ticagrelor attenuates vascular dysfunction and inhibits atherogenesis in apolipoprotein E-deficient (apoe-/-) mice. METHODS: Eight-week-old male apoe-/- mice were fed a western-type diet (WTD) supplemented with 0.1% ticagrelor (approximately 120â¯mg/kg/day). Non-treated animals on WTD served as control. Atherosclerotic lesions were examined by en-face Sudan IV staining, histological analyses, quantitative RT-PCR analysis, and western blotting. Endothelial function was analyzed by acetylcholine-dependent vasodilation using aortic rings. Human umbilical vein endothelial cells (HUVEC) were used for in vitro experiments. RESULTS: Ticagrelor treatment for 20 weeks attenuated atherosclerotic lesion progression in the aortic arch compared with control (pâ¯<â¯0.05). Ticagrelor administration for 8 weeks attenuated endothelial dysfunction (pâ¯<â¯0.01). Ticagrelor reduced the expression of inflammatory molecules such as vascular cell adhesion molecule-1, macrophage accumulation, and lipid deposition. Ticagrelor decreased the phosphorylation of JNK in the aorta compared with control (pâ¯<â¯0.05). Ticagrelor and a JNK inhibitor ameliorated impairment of endothelium-dependent vasodilation by adenosine diphosphate (ADP) in wild-type mouse aortic segments. Furthermore, ticagrelor inhibited the expression of inflammatory molecules which were promoted by ADP in HUVEC (pâ¯<â¯0.001). Ticagrelor also inhibited ADP-induced JNK activation in HUVEC (pâ¯<â¯0.05). CONCLUSIONS: Ticagrelor attenuated vascular dysfunction and atherogenesis through the inhibition of inflammatory activation of endothelial cells. These effects might be a potential mechanism by which ticagrelor decreases cardiovascular events in patients with ACS.