AIM To evaluate the levels of mi R-192-5 p in non-alcoholic fatty liver disease(NAFLD) models and demonstrate the role of mi R-192-5 p in lipid accumulation. METHODS Thirty Sprague Dawley rats were randomly divided in...AIM To evaluate the levels of mi R-192-5 p in non-alcoholic fatty liver disease(NAFLD) models and demonstrate the role of mi R-192-5 p in lipid accumulation. METHODS Thirty Sprague Dawley rats were randomly divided into three groups, which were given a standard diet, a high-fat diet(HFD), and an HFD with injection of liraglutide. At the end of 16 weeks, hepatic mi R-192-5 p and stearoyl-Co A desaturase 1(SCD-1) levels were measured. Mi R-192-5 p mimic and inhibitor and SCD-1 si RNA were transfected into Huh7 cells exposed to palmitic acid(PA). Lipid accumulation was evaluated by oil red O staining and triglyceride assays. Direct interaction was validated by dual-luciferase reporter gene assays.RESULTS The HFD rats showed a 0.46-fold decrease and a 3.5-fold increase in hepatic mi R-192-5 p and SCD-1 protein levels compared with controls, respectively, which could be reversed after disease remission by liraglutide injection(P < 0.01). The Huh7 cells exposed to PA also showed down-regulation and up-regulation of mi R-192-5 p and SCD-1 protein levels, respectively(P < 0.01). Transfection with mi R-192-5 p mimic and inhibitor in Huh7 cells induced dramatic repression and promotion of SCD-1 protein levels, respectively(P < 0.01). Luciferase activity was suppressed and enhanced by mi R-192-5 p mimic and inhibitor, respectively, in wild-type SCD-1(P < 0.01) but not in mutant SCD-1. Mi R-192-5 p overexpression reduced lipid accumulation significantly in PA-treated Huh7 cells, and SCD-1 si RNA transfection abrogated the lipid deposition aggravated by mi R-192-5 p inhibitor(P < 0.01).CONCLUSION This study demonstrates that mi R-192-5 p has a negative regulatory role in lipid synthesis, which is mediated through its direct regulation of SCD-1.展开更多
BACKGROUND:Non-alcoholic fatty liver disease(NAFLD)is one of the most frequent causes of liver diseases,with markedly increased prevalence.However,its mechanisms are not clear.The present study was undertaken to illus...BACKGROUND:Non-alcoholic fatty liver disease(NAFLD)is one of the most frequent causes of liver diseases,with markedly increased prevalence.However,its mechanisms are not clear.The present study was undertaken to illustrate the role of caveolin-1(cav1)and the scavenger receptor class B type 1(SR-B1)in NAFLD.METHODS:Adult male C57BL/6 mice were fed with a normal diet or high fat and cholesterol(HFC)diet for 14 weeks.The mice were sacrificed to collect plasma and harvest the liver;their plasma lipid concentration was measured.Hepatic cav1and SR-B1 mRNA and protein expression were determined by real-time quantitative polymerase chain reaction(qPCR)and Western blotting,respectively.In order to study cav1 and SR-B1distribution and change in hepatocytes,immunohistochemical analysis was performed.RESULTS:HFC diet increased plasma lipids,induced NAFLD and increased the liver/body weight ratio.Compared to the control mice(n=6),the mRNA and protein levels of cav1 and SR-B1 in liver tissue of the NAFLD mice(n=12)increased significantly(cav1 mRNA:1.536±0.226 vs 0.980±0.272,P【0.05;protein:0.643±0.240 vs 0.100±0.130,P【0.01;SR-B1 mRNA:1.377±0.125 vs 0.956±0.151,P【0.01;protein:2.156±0.507vs 0.211±0.211,P【0.01).Furthermore,both cav1 and SR-B1immunoreactivity increased and their distribution was also changed,mainly in the plasma membrane of hepatocytes,cytoplasm and membrane of lipid droplets and around.CONCLUSION:NAFLD is associated with increased concentration of plasma lipids and upregulation of hepatic cav1 and SR-B1 gene and protein expressions,which indicate that cav1 and SR-B1 might play crucial roles in the pathogenesis of NAFLD.展开更多
Non-alcoholic fatty liver disease（NAFLD） is a common liver disease and it represents the hepatic manifestation of metabolic syndrome, which includes type 2 diabetes mellitus（T2DM）, dyslipidemia, central obesity an...Non-alcoholic fatty liver disease（NAFLD） is a common liver disease and it represents the hepatic manifestation of metabolic syndrome, which includes type 2 diabetes mellitus（T2DM）, dyslipidemia, central obesity and hypertension. Glucagon-like peptide-1（GLP-1） analogues and dipeptidyl peptidase-4（DPP-4） inhibitors were widely used to treat T2 DM. These agents improve glycemic control, promote weight loss and improve lipid metabolism. Recent studies have demonstrated that the GLP-1 receptor（GLP-1R） is present and functional in human and rat hepatocytes. In this review, we present data from animal researches and human clinical studies that showed GLP-1 analogues and DPP-4 inhibitors can decrease hepatic triglyceride（TG） content and improve hepatic steatosis, although some effects could be a result of improvements in metabolic parameters. Multiple hepatocyte signal transduction pathways and m RNA from key enzymes in fatty acid metabolism appear to be activated by GLP-1 and its analogues. Thus, the data support the need for more rigorous prospective clinical trials to further investigate the potential of incretin therapies to treat patients with NAFLD.展开更多
BACKGROUND Zinc-α2-glycoprotein 1 (AZGP1) plays important roles in metabolism-related diseases. The underlying molecular mechanisms and therapeutic effects of AZGP1 remain unknown in non-alcoholic fatty liver disease...BACKGROUND Zinc-α2-glycoprotein 1 (AZGP1) plays important roles in metabolism-related diseases. The underlying molecular mechanisms and therapeutic effects of AZGP1 remain unknown in non-alcoholic fatty liver disease (NAFLD). AIM To explore the effects and potential mechanism of AZGP1 on NAFLD in vivo and in vitro. METHODS The expression of AZGP1 and its effects on hepatocytes were examined in NAFLD patients, CCl4-treated mice fed a high fat diet (HFD), and human LO2 cells. RESULTS AZGP1 levels were significantly decreased in liver tissues of NAFLD patients and mice. AZGP1 knockdown was found to activate inflammation;enhance steatogenesis, including promoting lipogenesis [sterol regulatory elementbinding protein (SREBP)-1c, liver X receptor (LXR), fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC), and stearoyl CoA desaturase 1 (SCD)-1], increasing lipid transport and accumulation [fatty acid transport protein (FATP), carnitine palmitoyl transferase (CPT)-1A, and adiponectin], and reducing fatty acid β-oxidation [farnesoid X receptor (FXR) and peroxisome proliferator-activated receptor (PPAR)-α];accelerate proliferation;and reverse apoptosis in LO2 cells. AZGP1 overexpression (OV-AZGP1) had the opposite effects. Furthermore, AZGP1 alleviated NAFLD by blocking TNF-α-mediated inflammation and intracellular lipid deposition, promoting proliferation, and inhibiting apoptosis in LO2 cells. Finally, treatment with OV-AZGP1 plasmid dramatically improved liver injury and eliminated liver fat in NAFLD mice. CONCLUSION AZGP1 attenuates NAFLD with regard to ameliorating inflammation, accelerating lipolysis, promoting proliferation, and reducing apoptosis by negatively regulating TNF-α. AZGP1 is suggested to be a novel promising therapeutic target for NAFLD.展开更多
基金Supported by National Key R&D Program of China No.2017YFC0908900National Key Basic Research Project,No.2012CB517501National Natural Science Foundation of China,No.81470840 and No.81600464
文摘AIM To evaluate the levels of mi R-192-5 p in non-alcoholic fatty liver disease(NAFLD) models and demonstrate the role of mi R-192-5 p in lipid accumulation. METHODS Thirty Sprague Dawley rats were randomly divided into three groups, which were given a standard diet, a high-fat diet(HFD), and an HFD with injection of liraglutide. At the end of 16 weeks, hepatic mi R-192-5 p and stearoyl-Co A desaturase 1(SCD-1) levels were measured. Mi R-192-5 p mimic and inhibitor and SCD-1 si RNA were transfected into Huh7 cells exposed to palmitic acid(PA). Lipid accumulation was evaluated by oil red O staining and triglyceride assays. Direct interaction was validated by dual-luciferase reporter gene assays.RESULTS The HFD rats showed a 0.46-fold decrease and a 3.5-fold increase in hepatic mi R-192-5 p and SCD-1 protein levels compared with controls, respectively, which could be reversed after disease remission by liraglutide injection(P < 0.01). The Huh7 cells exposed to PA also showed down-regulation and up-regulation of mi R-192-5 p and SCD-1 protein levels, respectively(P < 0.01). Transfection with mi R-192-5 p mimic and inhibitor in Huh7 cells induced dramatic repression and promotion of SCD-1 protein levels, respectively(P < 0.01). Luciferase activity was suppressed and enhanced by mi R-192-5 p mimic and inhibitor, respectively, in wild-type SCD-1(P < 0.01) but not in mutant SCD-1. Mi R-192-5 p overexpression reduced lipid accumulation significantly in PA-treated Huh7 cells, and SCD-1 si RNA transfection abrogated the lipid deposition aggravated by mi R-192-5 p inhibitor(P < 0.01).CONCLUSION This study demonstrates that mi R-192-5 p has a negative regulatory role in lipid synthesis, which is mediated through its direct regulation of SCD-1.
基金supported by a grant from the National Natural Science Foundation of China(491010-N11026)
文摘BACKGROUND:Non-alcoholic fatty liver disease(NAFLD)is one of the most frequent causes of liver diseases,with markedly increased prevalence.However,its mechanisms are not clear.The present study was undertaken to illustrate the role of caveolin-1(cav1)and the scavenger receptor class B type 1(SR-B1)in NAFLD.METHODS:Adult male C57BL/6 mice were fed with a normal diet or high fat and cholesterol(HFC)diet for 14 weeks.The mice were sacrificed to collect plasma and harvest the liver;their plasma lipid concentration was measured.Hepatic cav1and SR-B1 mRNA and protein expression were determined by real-time quantitative polymerase chain reaction(qPCR)and Western blotting,respectively.In order to study cav1 and SR-B1distribution and change in hepatocytes,immunohistochemical analysis was performed.RESULTS:HFC diet increased plasma lipids,induced NAFLD and increased the liver/body weight ratio.Compared to the control mice(n=6),the mRNA and protein levels of cav1 and SR-B1 in liver tissue of the NAFLD mice(n=12)increased significantly(cav1 mRNA:1.536±0.226 vs 0.980±0.272,P【0.05;protein:0.643±0.240 vs 0.100±0.130,P【0.01;SR-B1 mRNA:1.377±0.125 vs 0.956±0.151,P【0.01;protein:2.156±0.507vs 0.211±0.211,P【0.01).Furthermore,both cav1 and SR-B1immunoreactivity increased and their distribution was also changed,mainly in the plasma membrane of hepatocytes,cytoplasm and membrane of lipid droplets and around.CONCLUSION:NAFLD is associated with increased concentration of plasma lipids and upregulation of hepatic cav1 and SR-B1 gene and protein expressions,which indicate that cav1 and SR-B1 might play crucial roles in the pathogenesis of NAFLD.
基金supported in part by grants from the National Basic Research Program of China(No.2012CB524900)Department of Science&Technology of Shandong Province,China(Nos.2012GSF11824 and 2011780)
文摘Non-alcoholic fatty liver disease（NAFLD） is a common liver disease and it represents the hepatic manifestation of metabolic syndrome, which includes type 2 diabetes mellitus（T2DM）, dyslipidemia, central obesity and hypertension. Glucagon-like peptide-1（GLP-1） analogues and dipeptidyl peptidase-4（DPP-4） inhibitors were widely used to treat T2 DM. These agents improve glycemic control, promote weight loss and improve lipid metabolism. Recent studies have demonstrated that the GLP-1 receptor（GLP-1R） is present and functional in human and rat hepatocytes. In this review, we present data from animal researches and human clinical studies that showed GLP-1 analogues and DPP-4 inhibitors can decrease hepatic triglyceride（TG） content and improve hepatic steatosis, although some effects could be a result of improvements in metabolic parameters. Multiple hepatocyte signal transduction pathways and m RNA from key enzymes in fatty acid metabolism appear to be activated by GLP-1 and its analogues. Thus, the data support the need for more rigorous prospective clinical trials to further investigate the potential of incretin therapies to treat patients with NAFLD.
基金Supported by the National Natural Science Foundation of China,No.81570547 and No.81770597the Development Program of China during the 13~(th) Five-year Plan Period,No.2017ZX10203202003005
文摘BACKGROUND Zinc-α2-glycoprotein 1 (AZGP1) plays important roles in metabolism-related diseases. The underlying molecular mechanisms and therapeutic effects of AZGP1 remain unknown in non-alcoholic fatty liver disease (NAFLD). AIM To explore the effects and potential mechanism of AZGP1 on NAFLD in vivo and in vitro. METHODS The expression of AZGP1 and its effects on hepatocytes were examined in NAFLD patients, CCl4-treated mice fed a high fat diet (HFD), and human LO2 cells. RESULTS AZGP1 levels were significantly decreased in liver tissues of NAFLD patients and mice. AZGP1 knockdown was found to activate inflammation;enhance steatogenesis, including promoting lipogenesis [sterol regulatory elementbinding protein (SREBP)-1c, liver X receptor (LXR), fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC), and stearoyl CoA desaturase 1 (SCD)-1], increasing lipid transport and accumulation [fatty acid transport protein (FATP), carnitine palmitoyl transferase (CPT)-1A, and adiponectin], and reducing fatty acid β-oxidation [farnesoid X receptor (FXR) and peroxisome proliferator-activated receptor (PPAR)-α];accelerate proliferation;and reverse apoptosis in LO2 cells. AZGP1 overexpression (OV-AZGP1) had the opposite effects. Furthermore, AZGP1 alleviated NAFLD by blocking TNF-α-mediated inflammation and intracellular lipid deposition, promoting proliferation, and inhibiting apoptosis in LO2 cells. Finally, treatment with OV-AZGP1 plasmid dramatically improved liver injury and eliminated liver fat in NAFLD mice. CONCLUSION AZGP1 attenuates NAFLD with regard to ameliorating inflammation, accelerating lipolysis, promoting proliferation, and reducing apoptosis by negatively regulating TNF-α. AZGP1 is suggested to be a novel promising therapeutic target for NAFLD.
