Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 686
Filtrar
1.
Eur Heart J ; 39(27): 2562-2573, 2018 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-29982602

RESUMO

Aims: Low-density lipoprotein (LDL) particles cause atherosclerotic cardiovascular disease (ASCVD) through their retention, modification, and accumulation within the arterial intima. High plasma concentrations of LDL drive this disease, but LDL quality may also contribute. Here, we focused on the intrinsic propensity of LDL to aggregate upon modification. We examined whether inter-individual differences in this quality are linked with LDL lipid composition and coronary artery disease (CAD) death, and basic mechanisms for plaque growth and destabilization. Methods and results: We developed a novel, reproducible method to assess the susceptibility of LDL particles to aggregate during lipolysis induced ex vivo by human recombinant secretory sphingomyelinase. Among patients with an established CAD, we found that the presence of aggregation-prone LDL was predictive of future cardiovascular deaths, independently of conventional risk factors. Aggregation-prone LDL contained more sphingolipids and less phosphatidylcholines than did aggregation-resistant LDL. Three interventions in animal models to rationally alter LDL composition lowered its susceptibility to aggregate and slowed atherosclerosis. Similar compositional changes induced in humans by PCSK9 inhibition or healthy diet also lowered LDL aggregation susceptibility. Aggregated LDL in vitro activated macrophages and T cells, two key cell types involved in plaque progression and rupture. Conclusion: Our results identify the susceptibility of LDL to aggregate as a novel measurable and modifiable factor in the progression of human ASCVD.


Assuntos
Doença da Artéria Coronariana/sangue , Doença da Artéria Coronariana/mortalidade , Lipoproteínas LDL/sangue , Lipoproteínas LDL/fisiologia , Adulto , Animais , Feminino , Humanos , Lipídeos , Masculino , Camundongos , Pessoa de Meia-Idade , Prognóstico , Medição de Risco
3.
Br J Pharmacol ; 175(8): 1318-1328, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-28480509

RESUMO

BACKGROUND AND PURPOSE: The epithelial sodium channel (ENaC) is expressed in endothelial cells and acts as a negative modulator of vasodilatation. Oxidized LDL (ox-LDL) is a key pathological factor in endothelial dysfunction. In the present study we examined the role of ENaC in ox-LDL-induced endothelial dysfunction and its associated signal transduction pathway. EXPERIMENTAL APPROACH: Patch clamp techniques combined with pharmacological approaches were used to examine ENaC activity in the endothelial cells of a split-open mouse thoracic aorta. Western blot analysis was used to determine ENaC expression in the aorta. The aorta relaxation was measured using a wire myograph assay. KEY RESULTS: Ox-LDL, but not LDL, significantly increased ENaC activity in the endothelial cells attached to split-open thoracic aortas, and the increase was inhibited by a lectin-like ox-LDL receptor-1 (LOX-1) antagonist (κ-carrageenan), an NADPH oxidase inhibitor (apocynin), and a scavenger of ROS (TEMPOL). Sodium nitroprusside, an NO donor, diminished the ox-LDL-mediated activation of ENaC, and this effect was abolished by inhibiting soluble guanylate cyclase (sGC) and PKG. Ox-LDL reduced the endothelium-dependent vasodilatation of the aorta pectoralis induced by ACh, and this reduction was partially restored by blocking ENaC. CONCLUSION AND IMPLICATIONS: Ox-LDL stimulates ENaC in endothelial cells through LOX-1 receptor-mediated activation of NADPH oxidase and accumulation of intracellular ROS. Since the stimulation of ENaC can be reversed by elevating NO, we suggest that both inhibition of ENaC and an elevation of NO may protect the endothelium from ox-LDL-induced dysfunction. LINKED ARTICLES: This article is part of a themed section on Spotlight on Small Molecules in Cardiovascular Diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.8/issuetoc.


Assuntos
Células Endoteliais/fisiologia , Canais Epiteliais de Sódio/fisiologia , Lipoproteínas LDL/fisiologia , Animais , Aorta Torácica/citologia , Aorta Torácica/fisiologia , Técnicas In Vitro , Masculino , Camundongos Endogâmicos C57BL , Espécies Reativas de Oxigênio/metabolismo , Receptores Depuradores Classe E/fisiologia
4.
Ter Arkh ; 90(4): 100-104, 2018 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-30701883

RESUMO

The role of modified low density lipoprotein in the activation of the classical pathway of the complement system and increasing expression C3 gene in human macrophages is described, role of these processes on the progression of atherosclerotic vascular lesions is considering.


Assuntos
Aterosclerose , Complemento C3/metabolismo , Lipoproteínas LDL , Aterosclerose/metabolismo , Proteínas do Sistema Complemento , Humanos , Lipoproteínas LDL/fisiologia , Macrófagos
5.
Biol Reprod ; 97(6): 862-872, 2017 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-29092018

RESUMO

The membrane proteins, low-density lipoprotein receptor (LDLR) and scavenger receptor class B member 1 (SR-BI, gene name Scarb1), are lipoprotein receptors that play central roles in lipoprotein metabolism. Cholesterol bound in high-density lipoprotein (HDL) and LDL is transported into cells mainly by SR-BI and LDLR. The relative contribution of LDL and HDL to the steroidogenic cholesterol pool varies among species and may vary among tissues within one species. To investigate which of these pathways is more important in the supply of cholesterol in mouse ovary, we utilized immunohistochemistry, western blotting, RNAi, and RT-PCR as well as Ldlr-/- mice to explore the uptake of HDL and LDL in the ovary. Our data demonstrate that both SR-BI and LDLR are present in the interstitial cells, thecal cells, and corpora lutea (CLs), and their expression fluctuates with the development of follicles and CLs. The intracellular cholesterol concentration was significantly decreased when Ldlr or Scarb1 was silenced in luteal cells. Furthermore, Ldlr-/- mice had lower progesterone and estrogen levels compared to wild-type mice, and when Ldlr-/- mice were treated with the inhibitor of de novo cholesterol synthesis, lovastatin, serum progesterone, and estrogen concentrations were further reduced. These results demonstrate that both LDLR and SR-BI play important roles in importing cholesterol and that both HDL and LDL are crucial in steroidogenesis in mouse ovaries.


Assuntos
Estrogênios/sangue , Lipoproteínas HDL/fisiologia , Lipoproteínas LDL/fisiologia , Ovário/fisiologia , Progesterona/sangue , Receptores Depuradores Classe B/fisiologia , Animais , Células Cultivadas , Colesterol/metabolismo , Corpo Lúteo/fisiologia , Feminino , Inativação Gênica , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptores de LDL/fisiologia , Células Tecais/fisiologia
6.
J Cell Sci ; 130(20): 3542-3556, 2017 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-28821575

RESUMO

Low-density lipoprotein (LDL) receptor-related protein 6 (LRP6) was originally identified as a co-receptor of the Wnt signalling pathway and has been shown to be involved in LDL transport. In polarized hepatocytes, many apical proteins are sorted to the basolateral membrane and then internalized and transported to the apical bile canalicular membrane - a process known as transcytosis. We show that LRP6 is transcytosed to the apical membrane of polarized hepatic HepG2 cells via a flotillin-dependent manner in the absence of LDL. LRP6 formed a complex with Niemann-Pick type C1-like 1 (NPC1L1), which is localized to the bile canalicular membrane of the liver and is involved in cholesterol absorption from the bile. LRP6 was required for apical membrane localization of NPC1L1 in the absence of LDL. Clathrin-dependent LRP6 internalization occurred in the presence of LDL, which resulted in trafficking of LRP6 to the lysosome, thereby reducing apical sorting of LRP6 and NPC1L1. These results suggest that LRP6 endocytosis proceeds by two routes, depending on the presence of LDL, and that LRP6 controls the intracellular destination of NPC1L1 in hepatocytes.


Assuntos
Clatrina/metabolismo , Lipoproteínas LDL/fisiologia , Proteína-6 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Proteínas de Membrana/metabolismo , Polaridade Celular , Células Hep G2 , Humanos , Microdomínios da Membrana/metabolismo , Transporte Proteico , Transcitose
7.
Atherosclerosis ; 265: 292-298, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28734591

RESUMO

BACKGROUND AND AIMS: Type 2 diabetic patients have an increased proportion of electronegative low-density lipoprotein (LDL(-)), an inflammatory LDL subfraction present in blood, and dysfunctional high-density lipoprotein (HDL). We aimed at examining the inflammatory effect of LDL(-) on monocytes and the counteracting effect of HDL in the context of type 2 diabetes. METHODS: This was a cross-sectional study in which the population comprised 3 groups (n = 12 in each group): type 2 diabetic patients with good glycaemic control (GC-T2DM patients), type 2 diabetic patients with poor glycaemic control (PC-T2DM), and a control group. Total LDL, HDL, and monocytes were isolated from plasma of these subjects. LDL(-) was isolated from total LDL by anion-exchange chromatography. LDL(-) from the three groups of subjects was added to monocytes in the presence or absence of HDL, and cytokines released by monocytes were quantified by ELISA. RESULTS: LDL(-) proportion and plasma inflammatory markers were increased in PC-T2DM patients. LDL(-) from PC-T2DM patients induced the highest IL1ß, IL6, and IL10 release in monocytes compared to LDL(-) from GC-T2DM and healthy subjects, and presented the highest content of non-esterified fatty acids (NEFA). In turn, HDL from PC-T2DM patients showed the lowest ability to inhibit LDL(-)-induced cytokine release in parallel to an impaired ability to decrease NEFA content in LDL(-). CONCLUSIONS: Our findings show an imbalance in the pro- and anti-inflammatory effects of lipoproteins from T2DM patients, particularly in PC-T2DM.


Assuntos
Diabetes Mellitus Tipo 2/sangue , Inflamação/etiologia , Lipoproteínas HDL/fisiologia , Lipoproteínas LDL/fisiologia , Monócitos/fisiologia , Estudos Transversais , Humanos
8.
Toxicol Mech Methods ; 27(8): 615-621, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28627266

RESUMO

Oxidized low density lipoprotein (ox LDL) induced inflammatory response was reported to play an important role in the pathogenesis of atherosclerosis. The purpose of this study was to explore the anti-inflammatory effect of a novel formulation of coconut inflorescence sap (CSP); COCOZEN™ against ox-LDL induced inflammatory responses in human peripheral blood mononuclear cells (hPBMCs). The hPBMCs were isolated from healthy human volunteers and cultured in collagen coated plates at 37 °C. The cells were grouped as Group I (Control), Group II (ox-LDL treated) and Group III (ox-LDL + CSP treated). Further analysis of inflammatory markers, reactive oxygen species, mRNA and protein expression levels indicated increased expressions of TLR-4, TNF-α, IL-6 and VCAM-1 in ox-LDL treated group along with the nuclear translocation of NF-κB. Other inflammatory markers such as LOX, PGE2, NO, total COX and lipid peroxidation level were also found to be significantly (p < .05) increased upon Ox-LDL treatment. The treatment with CSP on the other hand was found to down regulate and reverse the ox-LDL-induced alterations indicating its potential anti-inflammatory effect on hPBMCs via TLR-NF-κB signaling pathway.


Assuntos
Anti-Inflamatórios/farmacologia , Cocos/química , Inflamação/fisiopatologia , Lipoproteínas LDL/fisiologia , Monócitos/metabolismo , NF-kappa B/metabolismo , Transdução de Sinais , Receptores Toll-Like/metabolismo , Células Cultivadas , Humanos
9.
Cell Biol Int ; 41(9): 1012-1019, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28653788

RESUMO

microRNAs (miRNAs) play important roles in the pathogenesis of atherosclerosis. A previous study has reported that miR-497 is elevated in advanced atherosclerotic lesions in an apoE-deficient (apoE-/-) mouse model. The purpose of this study is to test whether miR-497 can modulate macrophage foam cell formation, an initiating event in atherosclerosis. We found that miR-497 was upregulated in THP-1 macrophages after treatment with oxidized low-density lipoprotein (oxLDL). Enforced expression of miR-497 promoted lipid accumulation and decreased cholesterol efflux in oxLDL-exposed THP-1 macrophages. In contrast, downregulation of miR-497 suppressed oxLDL-induced lipid accumulation in THP-1 macrophages. Apelin was identified to be a downstream target of miR-497. Overexpression of miR-497 significantly reduced the expression of apelin in THP-1 macrophages. Interestingly, delivery of a miR-497-resistant variant of apelin significantly inhibited lipid accumulation and enhanced cholesterol efflux in miR-497-overexpressing THP-1 macrophages in response to oxLDL. In addition, miR-497 expression was increased and negatively correlated with apelin protein expression in human atherosclerotic lesions. In conclusion, miR-497 contributes to oxLDL-induced lipid deposition in macrophages largely via targeting of apelin and thus represents a potential therapeutic target for atherosclerosis.


Assuntos
Apelina/antagonistas & inibidores , Lipoproteínas LDL/fisiologia , Macrófagos/metabolismo , MicroRNAs/metabolismo , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Apelina/biossíntese , Apelina/genética , Apelina/metabolismo , Apolipoproteínas E/genética , Aterosclerose/genética , Aterosclerose/metabolismo , Colesterol/metabolismo , Células Espumosas/citologia , Células Espumosas/metabolismo , Humanos , Metabolismo dos Lipídeos/genética , Lipoproteínas LDL/genética , Lipoproteínas LDL/metabolismo , Lipoproteínas LDL/farmacologia , Macrófagos/citologia , MicroRNAs/genética , Células THP-1
10.
Eur Heart J ; 38(32): 2459-2472, 2017 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-28444290

RESUMO

Aims: To appraise the clinical and genetic evidence that low-density lipoproteins (LDLs) cause atherosclerotic cardiovascular disease (ASCVD). Methods and results: We assessed whether the association between LDL and ASCVD fulfils the criteria for causality by evaluating the totality of evidence from genetic studies, prospective epidemiologic cohort studies, Mendelian randomization studies, and randomized trials of LDL-lowering therapies. In clinical studies, plasma LDL burden is usually estimated by determination of plasma LDL cholesterol level (LDL-C). Rare genetic mutations that cause reduced LDL receptor function lead to markedly higher LDL-C and a dose-dependent increase in the risk of ASCVD, whereas rare variants leading to lower LDL-C are associated with a correspondingly lower risk of ASCVD. Separate meta-analyses of over 200 prospective cohort studies, Mendelian randomization studies, and randomized trials including more than 2 million participants with over 20 million person-years of follow-up and over 150 000 cardiovascular events demonstrate a remarkably consistent dose-dependent log-linear association between the absolute magnitude of exposure of the vasculature to LDL-C and the risk of ASCVD; and this effect appears to increase with increasing duration of exposure to LDL-C. Both the naturally randomized genetic studies and the randomized intervention trials consistently demonstrate that any mechanism of lowering plasma LDL particle concentration should reduce the risk of ASCVD events proportional to the absolute reduction in LDL-C and the cumulative duration of exposure to lower LDL-C, provided that the achieved reduction in LDL-C is concordant with the reduction in LDL particle number and that there are no competing deleterious off-target effects. Conclusion: Consistent evidence from numerous and multiple different types of clinical and genetic studies unequivocally establishes that LDL causes ASCVD.


Assuntos
Aterosclerose/etiologia , Lipoproteínas LDL/fisiologia , Anticolesterolemiantes/uso terapêutico , Aterosclerose/prevenção & controle , HDL-Colesterol/metabolismo , LDL-Colesterol/metabolismo , Consenso , Métodos Epidemiológicos , Ezetimiba/uso terapêutico , Predisposição Genética para Doença/genética , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Hiperlipidemias/prevenção & controle , Pró-Proteína Convertase 9/antagonistas & inibidores
11.
Exp Cell Res ; 353(1): 26-34, 2017 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-28274716

RESUMO

Pathogenesis of atherosclerosis is characterized by the proliferation and migration of vascular smooth muscle cells (VSMCs) and inflammatory lesions. The aim of this study is to elucidate the effect of atractylenolide I (AO-I) on smooth muscle cell inflammation, proliferation and migration induced by oxidized modified low density lipoprotein (Ox-LDL). Here, We found that atractylenolide I inhibited Ox-LDL-induced VSMCs proliferation and migration in a dose-dependent manner, and decreased the production of inflammatory cytokines and the expression of monocyte chemoattractant protein-1 (MCP-1) in VSMCs. The study also identified that AO-I prominently inhibited p38-MAPK and NF-κB activation. More importantly, the specific heme oxygenase-1 (HO-1) inhibitor zinc protoporphyrin (ZnPP) IX partially abolished the beneficial effects of atractylenolide I on Ox-LDL-induced VSMCs. Furthermore, atractylenolide I blocked the foam cell formation in macrophages induced by Ox-LDL. In summary, inhibitory roles of AO-I in VSMCs proliferation and migration, lipid peroxidation and subsequent inflammatory responses might contribute to the anti-atherosclerotic property of AO-I.


Assuntos
Heme Oxigenase-1/genética , Lactonas/farmacologia , Lipoproteínas LDL/fisiologia , Miócitos de Músculo Liso/fisiologia , Sesquiterpenos/farmacologia , Animais , Aterosclerose/tratamento farmacológico , Aterosclerose/imunologia , Aterosclerose/patologia , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Avaliação Pré-Clínica de Medicamentos , Feminino , Células Espumosas/efeitos dos fármacos , Células Espumosas/fisiologia , Heme Oxigenase-1/metabolismo , Masculino , Camundongos , Músculo Liso Vascular/citologia , Miócitos de Músculo Liso/efeitos dos fármacos , Ratos Sprague-Dawley
12.
Nucleosides Nucleotides Nucleic Acids ; 35(10-12): 713-719, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27906627

RESUMO

Extracellular nucleotides regulate thrombosis, inflammation, and immune response. Ectonucleoside triphosphate diphosphohydrolase 1 (CD39) and ecto-5'-nucleotidase (CD73) convert extracellular nucleotides in a sequential order: ATP to ADP, AMP, and then to adenosine. In this study, we aimed to test an effect of oxidized low-density lipoprotein (ox-LDL) on CD39 and CD73 in endothelial cells. Human aortic valve endothelial cells were exposed to ox-LDL for 24-48 h. Next, the activity, protein expression, and mRNA transcripts level of CD39 and CD73 were characterized by an incubation with ATP or AMP followed by high-performance liquid chromatography analysis of media as well as western blots and qPCR. CD73 activity in human valve endothelial cells was increased in presence of ox-LDL (4.04 ± 0.32 nmol/mg prot./min, mean +/- SEM) as compared with control (2.75 ± 0.21 nmol/mg prot/min). There was almost no effect of ox-LDL on CD39 activity. A similar effect was observed for mRNA and protein expression. In conclusion, we found that ox-LDL modulated CD39 and CD73 activity in the endothelium, which may contribute to relevant pathologies and featured treatments.


Assuntos
5'-Nucleotidase/metabolismo , Antígenos CD/metabolismo , Valva Aórtica/metabolismo , Apirase/metabolismo , Doenças das Valvas Cardíacas/metabolismo , Lipoproteínas LDL/fisiologia , 5'-Nucleotidase/genética , Adulto , Antígenos CD/genética , Valva Aórtica/patologia , Apirase/genética , Células Cultivadas , Endotélio Vascular/metabolismo , Endotélio Vascular/patologia , Feminino , Proteínas Ligadas por GPI/genética , Proteínas Ligadas por GPI/metabolismo , Expressão Gênica , Humanos , Masculino , Pessoa de Meia-Idade , Cultura Primária de Células , Adulto Jovem
13.
Zhong Nan Da Xue Xue Bao Yi Xue Ban ; 41(11): 1168-1174, 2016 Nov 28.
Artigo em Chinês | MEDLINE | ID: mdl-27932762

RESUMO

OBJECTIVE: To investigate the correlations between lipid ratio/oxidative stress status in chronic obstructive pulmonary disease (COPD) patients and pulmonary hypertension as well as the prognosis.
 Methods: A total of 120 patients with COPD were randomly selected and served as the COPD group and 30 healthy persons were selected as the control group. The ratios of low density lipoprotein (LDL)/high-density lipoprotein (HDL), triglyceride (TG)/HDL and total cholesterol (TC)/HDL were measured. The superoxide dismutase (SOD) activity, malondialdehyde (MDA) content and total antioxidant capacity (T-AOC) level in the control group and COPD patients were detected. Pulmonary hypertension incidence and 3-year survival rate for COPD patients were statistically analyzed. Spearman rank correlation method was used to analyze relationship between lipid ratio /oxidative stress status and pulmonary hypertension.
 Results: Compared with control group, the ratios of LDL/HDL, TG/HDL and TC/HDL, and the serum MDA level in the COPD group were increased, while the serum SOD and T-AOC level in the COPD group were decreased; compared with stable period, lipid ratios and MDA levels in the acute period were elevated, while serum SOD and T-AOC levels were reduced (P<0.05). Pulmonary hypertension incidence and 3-year survival rates in the COPD group were 56.67% and 81.67% respectively; the lipid ratios and serum MDA levels in COPD patients with pulmonary hypertension were elevated compared with that in COPD patients without pulmonary hypertension; the serum SOD and T-AOC levels in COPD patients with pulmonary hypertension were reduced compared with that in patients without pulmonary hypertension (P<0.05). Spearman rank correlation analysis showed that ratios of LDL/HDL, TG/HDL and TC/HDL, and the serum MDA levels in COPD patients were positively correlated with 3-years pulmonary hypertension incidence (r=0.752, 0.748, 0.752, 0.748; P<0.05), and negatively correlated with 3-years survival rate (r=-0.722, -0.751, -0.736, -0.748; P<0.05); serum SOD and T-AOC levels in COPD patients were negatively correlated with 3-years pulmonary hypertension (r=-0.711, -0.734; P<0.05), and positively correlated with 3-year survival rate (r=0.726, 0.733; P<0.05). 
 Conclusion: Blood lipid ratio and oxidative stress levels in COPD patients are elevated while antioxidant abilities were attenuated. The lipid ratio and oxidative stress status in COPD patients is closely related to the prognosis of pulmonary hypertension. Therefore, blood lipid ratio and oxidative stress status may be used in evaluation of pulmonary hypertension and prognosis for COPD patients.


Assuntos
Colesterol/fisiologia , Hipertensão Pulmonar/fisiopatologia , Lipoproteínas HDL/fisiologia , Lipoproteínas LDL/fisiologia , Estresse Oxidativo/fisiologia , Doença Pulmonar Obstrutiva Crônica/mortalidade , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Triglicerídeos/fisiologia , Biomarcadores/sangue , Colesterol/sangue , Feminino , Humanos , Lipídeos , Lipoproteínas HDL/sangue , Masculino , Malondialdeído , Prognóstico , Doença Pulmonar Obstrutiva Crônica/sangue , Superóxido Dismutase , Triglicerídeos/sangue
14.
J Am Coll Cardiol ; 68(15): 1664-1676, 2016 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-27712780

RESUMO

BACKGROUND: Carbamylation alters low-density lipoprotein (LDL) structure and is thought to promote vascular inflammation and dysfunction in patients with chronic kidney disease (CKD). OBJECTIVES: This study sought to determine whether carbamylated LDL (cLDL) exerts prothrombotic effects in vascular cells and platelets and whether cLDL enhances arterial thrombus formation in vivo. METHODS: LDL was isolated from healthy subjects or patients with CKD by sequential ultracentrifugation. Ex vivo carbamylation of LDL from healthy subjects was induced with potassium cyanate. Arterial thrombus formation was analyzed in a murine carotid artery photochemical injury model. Protein expression and mRNA levels were analyzed by Western blotting, flow cytometry, and real-time PCR. Platelet aggregation was measured by impedance aggregometry. RESULTS: Intravenous administration of cLDL in mice accelerated arterial thrombus formation compared to treatment with native LDL (nLDL) or vehicle. Tissue lysates of mouse carotid arteries revealed that cLDL induced the expression of TF, PAI-1, and LOX-1 mRNA in vascular cells. In human aortic smooth muscle and endothelial cells, cLDL induced TF and PAI-1 expression. In contrast, nLDL had no effect on either cell type. While nLDL and cLDL had no aggregatory effect on resting platelets, cLDL enhanced platelet aggregation in response to different agonists. This effect was mediated by mitogen-activated protein kinase p38 phosphorylation and LOX-1 translocation to the surface. LDL isolated from patients with CKD mimicked the prothrombotic effects of cLDL on vascular cells, platelets, and thrombus formation in vivo. CONCLUSIONS: We found that cLDL induces prothrombotic effects in vascular cells and platelets by activation of the LOX-1 receptor and enhances thrombus formation in vivo. This observation reveals a new mechanism underlying the increased incidence of acute thrombotic events observed in patients with CKD and may lead to the development of new lipid-targeting therapies in this population.


Assuntos
Lipoproteínas LDL/fisiologia , Insuficiência Renal Crônica/complicações , Receptores Depuradores Classe E/fisiologia , Trombose/etiologia , Animais , Artérias , Masculino , Camundongos , Camundongos Endogâmicos C57BL
15.
PLoS One ; 11(9): e0163046, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27636901

RESUMO

Elevated plasma concentration of the pro-atherogenic oxidized low density lipoprotein cholesterol (LDL) triggers adverse effects in pancreatic beta-cells and is associated with type 2 diabetes. Here, we investigated whether the endoplasmic reticulum (ER) stress is a key player coupling oxidative stress to beta-cell dysfunction and death elicited by human oxidized LDL. We found that human oxidized LDL activates ER stress as evidenced by the activation of the inositol requiring 1α, and the elevated expression of both DDIT3 (also called CHOP) and DNAJC3 (also called P58IPK) ER stress markers in isolated human islets and the mouse insulin secreting MIN6 cells. Silencing of Chop and inhibition of ER stress markers by the chemical chaperone phenyl butyric acid (PBA) prevented cell death caused by oxidized LDL. Finally, we found that oxidative stress accounts for activation of ER stress markers induced by oxidized LDL. Induction of Chop/CHOP and p58IPK/P58IPK by oxidized LDL was mimicked by hydrogen peroxide and was blocked by co-treatment with the N-acetylcystein antioxidant. As a conclusion, the harmful effects of oxidized LDL in beta-cells requires ER stress activation in a manner that involves oxidative stress. This mechanism may account for impaired beta-cell function in diabetes and can be reversed by antioxidant treatment.


Assuntos
Estresse do Retículo Endoplasmático , Ilhotas Pancreáticas/fisiopatologia , Lipoproteínas LDL/fisiologia , Estresse Oxidativo , Acetilcisteína/administração & dosagem , Fator 6 Ativador da Transcrição/metabolismo , Animais , Antioxidantes/administração & dosagem , Apoptose , Biomarcadores/metabolismo , Linhagem Celular , Endorribonucleases/metabolismo , Humanos , Peróxido de Hidrogênio/administração & dosagem , Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/patologia , Camundongos , Proteínas Serina-Treonina Quinases/metabolismo
16.
J Lipid Res ; 57(8): 1398-411, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27281478

RESUMO

Accumulated evidence shows that vanin-1 (VNN1) plays a key part in glucose metabolism. We explored the effect of VNN1 on cholesterol metabolism, inflammation, apoptosis in vitro, and progression of atherosclerotic plaques in apoE(-/-) mice. Oxidized LDL (Ox-LDL) significantly induced VNN1 expression through an ERK1/2/cyclooxygenase-2/PPARα signaling pathway. VNN1 significantly increased cellular cholesterol content and decreased apoAI and HDL-cholesterol (HDL-C)-mediated efflux by 25.16% and 23.13%, respectively, in THP-1 macrophage-derived foam cells (P < 0.05). In addition, VNN1 attenuated Ox-LDL-induced apoptosis through upregulation of expression of p53 by 59.15% and downregulation of expression of B-cell lymphoma-2 127.13% in THP-1 macrophage (P < 0.05). In vivo, apoE(-/-) mice were divided randomly into two groups and transduced with lentivirus (LV)-Mock or LV-VNN1 for 12 weeks. VNN1-treated mice showed increased liver lipid content and plasma levels of TG (124.48%), LDL-cholesterol (119.64%), TNF-α (148.74%), interleukin (IL)-1ß (131.81%), and IL-6 (156.51%), whereas plasma levels of HDL-C (25.75%) were decreased significantly (P < 0.05). Consistent with these data, development of atherosclerotic lesions was increased significantly upon infection of apoE(-/-) mice with LV-VNN1. These observations suggest that VNN1 may be a promising therapeutic candidate against atherosclerosis.


Assuntos
Amidoidrolases/fisiologia , Aterosclerose/enzimologia , Dieta Hiperlipídica/efeitos adversos , Animais , Apolipoproteínas E/genética , Apoptose , Aterosclerose/etiologia , Células CACO-2 , Ésteres do Colesterol/metabolismo , Proteínas Ligadas por GPI/fisiologia , Células Hep G2 , Células Endoteliais da Veia Umbilical Humana , Humanos , Metabolismo dos Lipídeos , Lipoproteínas LDL/fisiologia , Fígado/metabolismo , Receptores X do Fígado/metabolismo , Macrófagos/enzimologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , PPAR gama/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Ativação Transcricional , Proteína Supressora de Tumor p53/metabolismo
17.
J Lipid Res ; 57(8): 1435-46, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27256691

RESUMO

Dyslipidemia has been proven to capably develop and aggravate chronic kidney disease. We also report that electronegative LDL (L5) is the most atherogenic LDL. On the other hand, retinoic acid (RA) and RA receptor (RAR) agonist are reported to be beneficial in some kidney diseases. "Stimulated by retinoic acid 6" (STRA6), one retinol-binding protein 4 receptor, was recently identified to regulate retinoid homeostasis. Here, we observed that L5 suppressed STRA6 cascades [STRA6, cellular retinol-binding protein 1 (CRBP1), RARs, retinoid X receptor α, and retinol, RA], but L5 simultaneously induced apoptosis and fibrosis (TGFß1, Smad2, collagen 1, hydroxyproline, and trichrome) in kidneys of L5-injected mice and L5-treated renal tubular cells. These L5-induced changes of STRA6 cascades, renal apoptosis, and fibrosis were reversed in kidneys of LOX1(-/-) mice. LOX1 RNA silencing and inhibitor of c-Jun N-terminal kinase and p38MAPK rescued the suppression of STRA6 cascades and apoptosis and fibrosis in L5-treated renal tubular cells. Furthermore, crbp1 gene transfection reversed downregulation of STRA6 cascades, apoptosis, and fibrosis in L5-treated renal tubular cells. For mimicking STRA6 deficiency, efficient silencing of STRA6 RNA was performed and was found to repress STRA6 cascades and caused apoptosis and fibrosis in L1-treated renal tubular cells. In summary, this study reveals that electronegative L5 can cause kidney apoptosis and fibrosis via the suppression of STRA6 cascades, and implicates that STRA6 signaling may be involved in dyslipidemia-mediated kidney disease.


Assuntos
Apoptose , Rim/patologia , Lipoproteínas LDL/fisiologia , Proteínas de Membrana/metabolismo , Animais , Linhagem Celular , Dislipidemias/complicações , Dislipidemias/metabolismo , Fibrose , Humanos , Rim/metabolismo , Nefropatias/etiologia , Nefropatias/metabolismo , Sistema de Sinalização das MAP Quinases , Masculino , Camundongos Endogâmicos C57BL , Receptores Depuradores Classe E/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
18.
J Lipid Res ; 57(5): 791-808, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-26989083

RESUMO

Endothelial biomechanics is emerging as a key factor in endothelial function. Here, we address the mechanisms of endothelial stiffening induced by oxidized LDL (oxLDL) and investigate the role of oxLDL in lumen formation. We show that oxLDL-induced endothelial stiffening is mediated by CD36-dependent activation of RhoA and its downstream target, Rho kinase (ROCK), via inhibition of myosin light-chain phosphatase (MLCP) and myosin light-chain (MLC)2 phosphorylation. The LC-MS/MS analysis identifies 7-ketocholesterol (7KC) as the major oxysterol in oxLDL. Similarly to oxLDL, 7KC induces RhoA activation, MLCP inhibition, and MLC2 phosphorylation resulting in endothelial stiffening. OxLDL also facilitates formation of endothelial branching networks in 3D collagen gels in vitro and induces increased formation of functional blood vessels in a Matrigel plug assay in vivo. Both effects are RhoA and ROCK dependent. An increase in lumen formation was also observed in response to pre-exposing the cells to 7KC, an oxysterol that induces endothelial stiffening, but not to 5α,6α epoxide that does not affect endothelial stiffness. Importantly, loading cells with cholesterol prevented oxLDL-induced RhoA activation and the downstream signaling cascade, and reversed oxLDL-induced lumen formation. In summary, we show that oxLDL-induced endothelial stiffening is mediated by the CD36/RhoA/ROCK/MLCP/MLC2 pathway and is associated with increased endothelial angiogenic activity.


Assuntos
Células Endoteliais/patologia , Lipoproteínas LDL/fisiologia , Neovascularização Patológica/metabolismo , Proteína rhoA de Ligação ao GTP/metabolismo , Animais , Miosinas Cardíacas/metabolismo , Células Cultivadas , Células Endoteliais/metabolismo , Endotélio Vascular/metabolismo , Endotélio Vascular/patologia , Humanos , Camundongos Nus , Camundongos SCID , Cadeias Leves de Miosina/metabolismo , Transdução de Sinais , Rigidez Vascular , Quinases Associadas a rho/metabolismo
19.
Sci Rep ; 6: 22607, 2016 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-26932825

RESUMO

Oxidized low-density lipoprotein (ox-LDL) is, at least in part, responsible for angiogenesis in atherosclerotic regions. This effect of ox-LDL has been shown to be mediated through a specific receptor LOX-1. Here we describe the effect of miR-590-5p on ox-LDL-mediated angiogenesis in in vitro and in vivo settings. Human umbilical vein endothelial cells (HUVECs) were transfected with miR-590-5p mimic or inhibitor followed by treatment with ox-LDL. In other experiments, Marigel plugs were inserted in the mice subcutaneous space. Both in vitro and in vivo studies showed that miR-590-5p mimic (100 nM) inhibited the ox-LDL-mediated angiogenesis (capillary tube formation, cell proliferation and migration as well as pro-angiogenic signals- ROS, MAPKs, pro-inflammatory cytokines and adhesion-related proteins). Of note, miR-590-5p inhibitor (200 nM) had the opposite effects. The inhibitory effect of miR-590-5p on angiogenesis was mediated by inhibition of LOX-1 at translational level. The inhibition of LOX-1 by miR-590-5p was confirmed by luciferase assay. In conclusion, we show that MiR-590-5p inhibits angiogenesis by targeting LOX-1 and suppressing redox-sensitive signals.


Assuntos
Lipoproteínas LDL/antagonistas & inibidores , MicroRNAs/fisiologia , Neovascularização Patológica/fisiopatologia , Receptores Depuradores Classe E/fisiologia , Movimento Celular , Proliferação de Células , Células Endoteliais da Veia Umbilical Humana , Humanos , Lipoproteínas LDL/fisiologia
20.
Cereb Cortex ; 26(4): 1464-72, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25316333

RESUMO

When native and recombinant kainate receptors (KARs) are compared, there is a mismatch in several of their functional properties. While both generate currents, synaptic responses mediated by KARs have rarely observed in cultured hippocampal neurons. The recent discovery of auxiliary proteins for KARs, such as Netos, offers an explanation for these discrepancies. We found that the GluK5 KAR subunit and the ancillary proteins, Neto1 and Neto2, are not expressed by hippocampal neurons in culture. Therefore, we used this model to directly test whether these proteins are required for the synaptic localization of KARs. Transfection of GluK4, GluK5, Neto1, or Neto2 into hippocampal neurons was associated with the appearance of synaptic KAR-mediated EPSCs. However, GluK4 or GluK5 alone produced synaptic activity in a significant proportion of cells and with reliable event frequency. While neurons expressing GluK4 or GluK5 subunits displayed synaptic responses with rapid kinetics, the expression of Neto proteins conferred these synaptic responses with their characteristic slow onset and decay rates. These data reveal some requirements for KAR targeting to the synapse, indicating a fundamental role of high affinity KAR subunits in this process.


Assuntos
Hipocampo/metabolismo , Lipoproteínas LDL/metabolismo , Proteínas de Membrana/metabolismo , Neurônios/metabolismo , Receptores de Ácido Caínico/metabolismo , Sinapses/metabolismo , Animais , Células Cultivadas , Potenciais Pós-Sinápticos Excitadores , Células HEK293 , Hipocampo/fisiologia , Humanos , Proteínas Relacionadas a Receptor de LDL , Lipoproteínas LDL/fisiologia , Proteínas de Membrana/fisiologia , Camundongos , Neurônios/fisiologia , Subunidades Proteicas/metabolismo , Subunidades Proteicas/fisiologia , Transporte Proteico , Receptores de Ácido Caínico/fisiologia , Sinapses/fisiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA