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1.
Proteomics ; 17(1-2)2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27928909

RESUMO

Over activity of cannabinoid receptor type 1 (CB1R) plays a key role in increasing the incidence of obesity-induced non-alcoholic fatty liver disease. Tissue proteome analysis has been applied to investigate the bioinformatics regarding the mode of action and therapeutic mechanism. The aim of this study was to explore the potential pathways altered with CB1R in obesity-induced fatty liver. Male C57BL/6 mice were fed either a standard chow diet (STD) or a high-fat diet (HFD) with or without 1-week treatment of CB1R inverse agonist AM251 at 5 mg/kg. Then, liver tissues were harvested for 2DE analysis and protein profiles were identified by using MALDI-MS. Results showed that eight of significantly altered protein spots at the level of changes > twofold were overlapped among the three groups, naming major urinary protein 1, ATP synthase subunit ß, glucosamine-fructose-6-phosphate aminotransferase 1, zine finger protein 2, s-adenosylmethionine synthase isoform type-1, isocitrate dehydrogenase subunit α, epoxide hydrolase 2 and 60S acidic ribosomal protein P0. These identified proteins were involved in glucose/lipid metabolic process, xenobiotic metabolic system, and ATP synthesized process in mitochondria. Based on the findings, we speculated that CB1R blockade might exert its anti-metabolic disorder effect via improvement of mitochondrial function in hepatic steatosis in HFD condition.


Assuntos
Biomarcadores/sangue , Antagonistas de Receptores de Canabinoides/uso terapêutico , Hepatopatia Gordurosa não Alcoólica/sangue , Piperidinas/uso terapêutico , Proteômica/métodos , Pirazóis/uso terapêutico , Receptores de Canabinoides/metabolismo , Animais , Dieta Hiperlipídica/efeitos adversos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Hepatopatia Gordurosa não Alcoólica/metabolismo
2.
Int J Mol Med ; 37(3): 743-54, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26847930

RESUMO

Hepatic glucose production is promoted by forkhead box O1 (FoxO1) under conditions of insulin resistance. The overactivity of cannabinoid receptor type 1 (CB1R) partly causes increased liver fat deposits and metabolic dysfunction in obese rodents by decreasing mitochondrial function. The aim of the present study was to investigate the role of FoxO1 in CB1R-mediated insulin resistance through the dysregulation of mitochondrial function in the livers of mice with high-fat diet (HFD)-induced obesity. For this purpose, male C57BL/6 mice were randomly assigned to groups and either fed a standard diet (STD), a HFD, or a HFD with 1-week treatment of the CB1R inverse agonist, AM251, at 1 or 5 mg/kg. For in vitro experiments, AML12 hepatocytes were incubated with FoxO1 siRNA prior to challenge with arachidonyl-2'-chloroethylamide (ACEA) or a high concentration of free fatty acids (HFFA). Plasma parameters were analyzed using colorimetric methods. Liver histopathology and hepatic status markers were examined. The HFD-fed mice exhibited an increase in CB1R levels in the liver. Moreover, in response to increased hepatic oxidative stress, the HFD-fed mice also displayed hepatic mitochondrial dysfunction, as indicated by the decreased mRNA levels of carnitine palmitoyltransferase-1 (CPT-1), mitochondrial transcription factor A (TFAM), nuclear respiratory factor-1 (NRF-1) and citrate synthase. On the contrary, these effects in the HFD-fed mice were reversed by treatment with 5 mg/kg AM251. The administration of AM251 suppressed the induction of FoxO1, phosphoenolpyruvate carboxykinase (PEPCK) and glucose 6-phosphatase (G6Pase) expression in the livers of the mice fed a HFD by enhancing the phosphorylation of insulin signaling cascades thus, further lowering the high level of the homeostatic model assessment of insulin resistance (HOMA­IR) index. In our in vitro experiments, transfection with FoxO1 siRNA prevented the HFFA- and ACEA-induced decrease in the gene expression of mitochondrial biogenesis-related factors, and abrogated the HFFA- and ACEA-induced increase in PEPCK and G6Pase expression. Taken together, our findings suggest that the anti-insulin resistance effect of AM251, which leads to an improvement of mitochondrial function in hepatic steatosis, is mediated through FoxO1.


Assuntos
Dieta Hiperlipídica/efeitos adversos , Proteína Forkhead Box O1/metabolismo , Resistência à Insulina/fisiologia , Obesidade/metabolismo , Receptores de Canabinoides/metabolismo , Animais , Agonistas de Receptores de Canabinoides/farmacologia , Citrato (si)-Sintase/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas de Grupo de Alta Mobilidade/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fator 1 Relacionado a NF-E2/metabolismo , Piperidinas/farmacologia , Pirazóis/farmacologia
3.
Biochem Biophys Res Commun ; 460(4): 1063-8, 2015 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-25843798

RESUMO

Hepatic insulin resistance (HIR) is a metabolic abnormality characterized by increased gluconeogenesis which usually contributes from an elevation of free fatty acids. Cannabinoid receptor type 1 (CB1R) and major urinary protein 1 (MUP1) are thought to play pivotal roles in mitochondrial dysfunction, liver steatosis and insulin resistance. The aim of this study was to explore the role of MUP1 in CB1R-mediated HIR through the dysregulation of mitochondrial function in AML12 mouse hepatocytes challenged with high concentration of free fatty acids (HFFA). Firstly we observed that treatment of AM251, a selective CB1R antagonist, obviously reversed the HFFA-induced reduction of MUP1 protein expression both in vivo and in vitro. Additionally, our results revealed that AM251 also reverted HFFA-mediated decrease of the mRNA level of mitochondrial biogenesis-related factors, mtDNA amount, ATP production, mitochondrial respiratory complexes-I and -III, and mitochondrial membrane potential, thus consequently might correlate with a parallel reduction of ROS production. Meanwhile, AM251 attenuated HFFA-induced impairment of insulin signaling phosphorylation and elevation of phosphoenolpyrvate carboxykinase (PEPCK) and glucose 6-phosphatase (G6Pase), two key enzymes of gluconeogenesis. Silence of MUP1 gene abolished the inhibitory effect of AM251 on HFFA-mediated elevation of PEPCK and G6Pase expression, whereas the suppression of insulin signaling and mRNA level of mitochondrial biogenesis-related factors were only partially recovered. Altogether, these findings suggest that the anti-HIR effect of AM251 via improvement of mitochondrial functions might occur in a MUP1-dependent manner.


Assuntos
Ácidos Graxos/metabolismo , Hepatócitos/metabolismo , Resistência à Insulina , Fígado/metabolismo , Proteínas/metabolismo , Receptor CB1 de Canabinoide/metabolismo , Animais , Western Blotting , Dieta Hiperlipídica , Inativação Gênica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Modelos Biológicos , Piperidinas/farmacologia , Proteínas/genética , Pirazóis/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Receptor CB1 de Canabinoide/antagonistas & inibidores
4.
Biochem Biophys Res Commun ; 460(3): 497-503, 2015 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-25824048

RESUMO

Endothelin-1 (ET-1) is known as potent vasoconstrictor, by virtue of its mitogenic effects, and may deteriorate the process of hypertension and atherosclerosis by aggravating hyperplasia and migration in VSMCs. Our previous study demonstrated that insulin infusion caused sequential induction of hyperinsulinemia, hyperendothelinemia, insulin resistance, and then hypertension in rats. However, the underlying mechanism of ET-1 interfere insulin signaling in VSMCs remains unclear. To characterize insulin signaling during modest insulin resistant syndrome, we established and monitored rats by feeding high fructose-diet (HFD) until high blood pressure and modest insulin resistance occurred. To explore the role of ET-1/ETAR during insulin resistance, ETAR expression, ET-1 binding, and insulin signaling were investigated in the HFD-fed rats and cultured A-10 VSMCs. Results showed that high blood pressure, tunica medial wall thickening, plasma ET-1 and insulin, and accompanied with modest insulin resistance without overweight and hyperglycemia occurred in early-stage HFD-fed rats. In the endothelium-denuded aorta from HFD-fed rats, ETAR expression, but not ETBR, and ET-1 binding in aorta were increased. Moreover, decreasing of insulin-induced Akt phosphorylation and increasing of insulin-induced ERK phosphorylation were observed in aorta during modest insulin resistance. Interestingly, in ET-1 pretreated VSMCs, the increment of insulin-induced Akt phosphorylation was decreased whereas the increment of insulin-induced ERK phosphorylation was increased. In addition, insulin potentiated ET-1-induced VSMCs migration and proliferation due to increasing ET-1 binding. ETAR antagonist reversed effects of ET-1 on insulin-induced signaling and VSMCs migration and proliferation. In summary, modest insulin resistance syndrome accompanied with hyperinsulinemia leading to the potentiation on ET-1-induced actions in aortic VSMCs. ET-1 via ETAR pathway suppressed insulin-induced AKT activation, whereas remained insulin-induced ERK activation. ET-1 and insulin synergistically potentiated migration and proliferation mainly through ETAR/ERK dependent pathway, which is dominant in VSMCs during modest insulin resistance syndrome. Therefore, ET-1 and ETAR are potential targets responsible for the observed synergism effect in the hypertensive atherosclerotic process through enhancement of ET-1 binding, ET-1 binding, ETAR expression, and ET-1-induced mitogenic actions in aortic VSMCs.


Assuntos
Aterosclerose/etiologia , Endotelina-1/fisiologia , Hipertensão/etiologia , Resistência à Insulina , Animais , Aterosclerose/fisiopatologia , Células Cultivadas , Dieta Hiperlipídica , Modelos Animais de Doenças , Endotelina-1/metabolismo , Hipertensão/fisiopatologia , Insulina/administração & dosagem , Músculo Liso Vascular/citologia , Músculo Liso Vascular/metabolismo , Fosforilação , Ratos , Ratos Sprague-Dawley
5.
Biochem Biophys Res Commun ; 451(2): 263-9, 2014 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-25088996

RESUMO

Endothelin-1 (ET-1) is the most potent vasoconstrictor by binding to endothelin receptors (ETAR) in vascular smooth muscle cells (VSMCs). The complex of angiotensin II (Ang II) and Ang II type one receptor (AT1R) acts as a transient constrictor of VSMCs. The synergistic effect of ET-1 and Ang II on blood pressure has been observed in rats; however, the underlying mechanism remains unclear. We hypothesize that Ang II leads to enhancing ET-1-mediated vasoconstriction through the activation of endothelin receptor in VSMCs. The ET-1-induced vasoconstriction, ET-1 binding, and endothelin receptor expression were explored in the isolated endothelium-denuded aortae and A-10 VSMCs. Ang II pretreatment enhanced ET-1-induced vasoconstriction and ET-1 binding to the aorta. Ang II enhanced ETAR expression, but not ETBR, in aorta and increased ET-1 binding, mainly to ETAR in A-10 VSMCs. Moreover, Ang II-enhanced ETAR expression was blunted and ET-1 binding was reduced by AT1R antagonism or by inhibitors of PKC or ERK individually. In conclusion, Ang II enhances ET-1-induced vasoconstriction by upregulating ETAR expression and ET-1/ETAR binding, which may be because of the AngII/Ang II receptor pathways and the activation of PKC or ERK. These findings suggest the synergistic effect of Ang II and ET-1 on the pathogenic development of hypertension.


Assuntos
Angiotensina II/metabolismo , Endotelina-1/metabolismo , Receptor de Endotelina A/genética , Receptor de Endotelina A/metabolismo , Vasoconstrição/fisiologia , Angiotensina II/farmacologia , Bloqueadores do Receptor Tipo 1 de Angiotensina II/farmacologia , Bloqueadores do Receptor Tipo 2 de Angiotensina II/farmacologia , Animais , Aorta Torácica/efeitos dos fármacos , Aorta Torácica/metabolismo , Linhagem Celular , Imidazóis/farmacologia , Losartan/farmacologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Miócitos de Músculo Liso/efeitos dos fármacos , Miócitos de Músculo Liso/metabolismo , Proteína Quinase C/metabolismo , Piridinas/farmacologia , Ratos , Ratos Sprague-Dawley , Regulação para Cima , Vasoconstrição/efeitos dos fármacos
6.
J Cell Physiol ; 226(8): 2198-205, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21520072

RESUMO

Endothelin-1 (ET-1), a potent proatherogenic vasoconstrictive peptide, is known to promote macrophage foam cell formation via mechanisms that are not fully understood. Excessive lipid accumulation in macrophages is a major hallmark during the early stages of atherosclerotic lesions. Cholesterol homeostasis is tightly regulated by scavenger receptors (SRs) and ATP-binding cassette (ABC) transporters during the transformation of macrophage foam cells. The aim of this study was to investigate the possible mechanisms by which ET-1 affects lipid accumulation in macrophages. Our results demonstrate that oxidized low-density lipoprotein (oxLDL) treatment increases lipid accumulation in rat bone marrow-derived macrophages. Combined treatment with ET-1 and oxLDL significantly exacerbated lipid accumulation in macrophages as compared to treatment with oxLDL alone. The results of Western blotting show that ET-1 markedly decreased the ABCG1 levels via ET type A and B receptors and activation of the phosphatidylinositol 3-kinase pathway; however, ET-1 had no effect on the protein expression of CD36, SR-BI, SR-A, or ABCA1. In addition, real-time PCR analysis showed that ET-1 treatment did not affect ABCG1 mRNA expression. We also found that ET-1 decreases ABCG1 possibly due to the enhancement of the proteosome/calpain pathway-dependent degradation of ABCG1. Moreover, ET-1 significantly reduced the efficiency of the cholesterol efflux in macrophages. Taken together, these findings suggest that ET-1 may impair cholesterol efflux and further exacerbate lipid accumulation during the transformation of macrophage foam cells.


Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Endotelina-1/metabolismo , Metabolismo dos Lipídeos , Macrófagos/metabolismo , Membro 1 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Animais , Calpaína/metabolismo , Endotelina-1/farmacologia , Regulação da Expressão Gênica , Lipoproteínas LDL/metabolismo , Lipoproteínas LDL/farmacologia , Macrófagos/química , Macrófagos/citologia , Fosfatidilinositol 3-Quinase/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Ratos , Ratos Sprague-Dawley , Receptor de Endotelina A/metabolismo , Receptor de Endotelina B/metabolismo
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