Background:Liqi Huoxue dripping pill(LQHXDP),a traditional Chinese drug for coronary heart disease,has a protective effect on the heart of rats with myocardial ischemia-reperfusion injury(MIRI)in previous studies;howe...Background:Liqi Huoxue dripping pill(LQHXDP),a traditional Chinese drug for coronary heart disease,has a protective effect on the heart of rats with myocardial ischemia-reperfusion injury(MIRI)in previous studies;however,its mechanism of action remains unclear.The purpose of this study was to investigate the protective mechanism of LQHXDP on MIRI in rats and its relationship with the PI3K/Akt signaling pathway.Methods:In this study,Sprague-Dawley rats were pre-infused with LQHXDP(175 mg/kg/d)for 10 days.PI3K inhibitor LY294002(0.3 mg/kg)was intravenously injected 15 minutes before ischemia.The rat model of MIRI was established by ligating the left anterior descending coronary artery.Subsequently,cardiac hemodynamics,serum myocardial injury markers,inflammatory factors,myocardial infarct size,antioxidant indexes,myocardial histopathology,and phosphorylation levels of key proteins of PI3K/Akt signaling pathway were assessed in rats.Results:LQHXDP was found to improve cardiac hemodynamic indexes,reduce serum creatine kinase MB isoenzyme activity and cardiac troponin and heart-type fatty acid binding protein levels,lower serum interleukin-1 beta,interleukin-6 and tumour necrosis factorαlevels,reduce the myocardial infarct size and enhance the antioxidant capacity of myocardial tissue in MIRI rats.Pathological analysis revealed that LQHXDP attenuated the extent of myocardial injury and protected mitochondria from damage in MIRI rats.Immunoblot analysis revealed that LQHXDP increased the expression levels of p-Akt and p-GSK-3βin MIRI rat cardiomyocytes.PI3K inhibitor LY294002 could impair these effects of LQHXDP.Conclusion:LQHXDP attenuated myocardial injury,attenuated oxidative stress injury and reduced inflammatory response in MIRI rats,and its protective effects were mediated by activating of PI3K/Akt/GSK-3βsignaling pathway.展开更多
Aim Previous studies showed that the inhibition of proteasome activity could significantly improve cardi- ac hypertrophy, but its mechanism is not clear. Increased glycogen synthase kinase-3 （GSK-3） activity can als...Aim Previous studies showed that the inhibition of proteasome activity could significantly improve cardi- ac hypertrophy, but its mechanism is not clear. Increased glycogen synthase kinase-3 （GSK-3） activity can also improve cardiac hypertrophy. However, the relationship between proteasome and GSK-3 has not been reported in cardiomyocyte In this study, we will investigate the effect of proteasome inhibition on cardiomyocyte hypertrophy, GSK-3 activity and the underlying mechanism. Methods Primary neonatal rat cardiomyocytes were divided into 4 groups： Control, Ang H （100 nmol · L^-1 48 h） Ang Ⅱ （ 100 nmol · L^-1） ＋ MG132 （0.05 μmol · L^-1） MG132 （0.05 μmol · L^-1） ,Ang 11 （100 nmol · L^-1 ） ＋ MG132 ＋ LiC1 （ 10 mmol · L^-1 ）, LiC1. Proteasome activitiy was detected by fluorescent peptide substrate. Cardiomyocyte surface area, ANF mRNA expression, and the rate of protein synthesis were observed as myocardial hypertrophy index. GSK-3, Akt, AMPKoL, and Histone3 （H3） were detected by Western Blot. The expression of GATA4 in the cytoplasm and nucleus was observed by im- munofluorescence. Results （1） Compared with the control group, myocardial ANF mRNA expression, the rate of protein synthesis and cell surface area were all increased in Ang H group. The chymotrypsin-like, trypsin-like and caspase-like activities of proteasome were all increased significantly. The phosphorylated level of both GSK-3α（ p- GSK-3α） （ Ser21 ） and GSK-3β （p-GSK-3β ） （Ser9） increased, i. e they were inactivated. （2） Compared with the Ang II group, myocardial ANF mRNA expression, the rate of protein synthesis and cell surface area were all decreased after proteasome inhibition. And p-GSK-3 （Ser21） and p-GSK-3β （Ser9） was respondingly decreased, （3） Proteasome inhibition also resulted in the decrease of p-Akt （Ser473） and p-AMPKa （Thr172）7 which in- creased in cardiomyocyte hypertrophy. Immunofluorescence showed that GATA4 was mainly distributed in the nu- cleus after Ang II treatment, while it was obviously increased in the cytoplasm after proteasome inhibition. After the GSK-3 inhibitor-LiC1 was given, the above indicators were reversed. （4） p-Histone3 was also increased in cardio- myocyte hypertrophy and MG132 reduced its level, but LiC1 treatment had no significant effect on its level. Con- clusion Proteasome inhibition reduces cardiomyocyte hypertrophy through increase of GSK-3a/b activity, which may be related with the decrease of Akt and AMPKa activities, and the decrease of nucleus location of GATA4, but p-histone3 is not involved.展开更多
Dihydromyricetin(DHM),as a bioactive flavanonol compound,is mainly found in“Tengcha”(Ampelopsis grossedentata)cultivated in south of China.This study aimed to investigate the anti-hyperglycemic and antidyslipidemic ...Dihydromyricetin(DHM),as a bioactive flavanonol compound,is mainly found in“Tengcha”(Ampelopsis grossedentata)cultivated in south of China.This study aimed to investigate the anti-hyperglycemic and antidyslipidemic activities of DHM using type 2 diabetes mellitus(T2D)rats,which was induced by feeding with high fat and fructose diet for 42 days and intraperitoneal administration of streptozocin.Forty-eight freshlyweaned rats were randomly assigned into the negative control(Blank),low dose(100 mg/kg),medium dose(200 mg/kg),high dose(400 mg/kg),and positive(40 mg/kg,met)groups.Fasting blood glucose and body weight were measured at weekly interval.Oral glucose tolerance tests were performed on days 42.The results revealed that DHM possessed significant antihyperglycaemic and antihyperinsulinemic effects.Moreover,after the DHM treatment,p-Akt and p-AMPK expression was upregulated,and glycogen synthase kinase-3β(GSK-3β)expression was downregulated,indicating that the potential anti-diabetic mechanism of DHM might be due to the regulation of the AMPK/Akt/GSK-3βsignaling pathway.展开更多
Throughout the globe,diabetes mellitus（DM） is increasing in incidence with limited therapies presently available to prevent or resolve the significant complications of this disorder.DM impacts multiple organs and af...Throughout the globe,diabetes mellitus（DM） is increasing in incidence with limited therapies presently available to prevent or resolve the significant complications of this disorder.DM impacts multiple organs and affects all components of the central and peripheral nervous systems that can range from dementia to diabetic neuropathy.The mechanistic target of rapamycin（m TOR） is a promising agent for the development of novel regenerative strategies for the treatment of DM.m TOR and its related signaling pathways impact multiple metabolic parameters that include cellular metabolic homeostasis,insulin resistance,insulin secretion,stem cell proliferation and differentiation,pancreatic β-cell function,and programmed cell death with apoptosis and autophagy.m TOR is central element for the protein complexes m TOR Complex 1（m TORC1） and m TOR Complex 2（m TORC2） and is a critical component for a number of signaling pathways that involve phosphoinositide 3-kinase（PI 3-K）,protein kinase B（Akt）,AMP activated protein kinase（AMPK）,silent mating type information regulation 2 homolog 1（Saccharomyces cerevisiae）（SIRT1）,Wnt1 inducible signaling pathway protein 1（WISP1）,and growth factors.As a result,m TOR represents an exciting target to offer new clinical avenues for the treatment of DM and the complications of this disease.Future studies directed to elucidate the delicate balance m TOR holds over cellular metabolism and the impact of its broad signaling pathways should foster the translation of these targets into effective clinical regimens for DM.展开更多
This study investigated the specific mechanism of knockdown of neuropeptide Y(NPY) in reducing obesity-induced insulin resistance in the white adipose tissue. Adeno-associated virus(AAV)-mediated RNAi was utilized to ...This study investigated the specific mechanism of knockdown of neuropeptide Y(NPY) in reducing obesity-induced insulin resistance in the white adipose tissue. Adeno-associated virus(AAV)-mediated RNAi was utilized to downregulate NPY expression in rats fed either regular chow or high fat diet. By investigating the differences in rat body weight and food intake, we assessed the effect of knockdown of NPY expression on insulin sensitivity and β-cell proliferation. Glucose consumption and 2-[3 H]DG uptake in 3 T3-L1 adipocytes were assessed to determine the molecular mechanisms. The results showed that knockdown of NPY expression in the dorsomedial hypothalamus(DMH) reduced obesity-induced insulin resistance, increased glucose consumption, and decreased 2-[3 H]DG uptake in 3 T3-L1 adipocytes via the PI3 K/Akt/GSK-3β signaling pathways and the NPY Y5 receptor.展开更多
基金supported by National Natural Science Foundation of China(Grant No.81860873 and 81960864)the Scientific and Technological Projects of Guizhou Province(Qian Kehe Jichu(2016)1401)High-level Talents Project of Guizhou Province(GUTCM(ZQ2018005)).
文摘Background:Liqi Huoxue dripping pill(LQHXDP),a traditional Chinese drug for coronary heart disease,has a protective effect on the heart of rats with myocardial ischemia-reperfusion injury(MIRI)in previous studies;however,its mechanism of action remains unclear.The purpose of this study was to investigate the protective mechanism of LQHXDP on MIRI in rats and its relationship with the PI3K/Akt signaling pathway.Methods:In this study,Sprague-Dawley rats were pre-infused with LQHXDP(175 mg/kg/d)for 10 days.PI3K inhibitor LY294002(0.3 mg/kg)was intravenously injected 15 minutes before ischemia.The rat model of MIRI was established by ligating the left anterior descending coronary artery.Subsequently,cardiac hemodynamics,serum myocardial injury markers,inflammatory factors,myocardial infarct size,antioxidant indexes,myocardial histopathology,and phosphorylation levels of key proteins of PI3K/Akt signaling pathway were assessed in rats.Results:LQHXDP was found to improve cardiac hemodynamic indexes,reduce serum creatine kinase MB isoenzyme activity and cardiac troponin and heart-type fatty acid binding protein levels,lower serum interleukin-1 beta,interleukin-6 and tumour necrosis factorαlevels,reduce the myocardial infarct size and enhance the antioxidant capacity of myocardial tissue in MIRI rats.Pathological analysis revealed that LQHXDP attenuated the extent of myocardial injury and protected mitochondria from damage in MIRI rats.Immunoblot analysis revealed that LQHXDP increased the expression levels of p-Akt and p-GSK-3βin MIRI rat cardiomyocytes.PI3K inhibitor LY294002 could impair these effects of LQHXDP.Conclusion:LQHXDP attenuated myocardial injury,attenuated oxidative stress injury and reduced inflammatory response in MIRI rats,and its protective effects were mediated by activating of PI3K/Akt/GSK-3βsignaling pathway.
文摘Aim Previous studies showed that the inhibition of proteasome activity could significantly improve cardi- ac hypertrophy, but its mechanism is not clear. Increased glycogen synthase kinase-3 （GSK-3） activity can also improve cardiac hypertrophy. However, the relationship between proteasome and GSK-3 has not been reported in cardiomyocyte In this study, we will investigate the effect of proteasome inhibition on cardiomyocyte hypertrophy, GSK-3 activity and the underlying mechanism. Methods Primary neonatal rat cardiomyocytes were divided into 4 groups： Control, Ang H （100 nmol · L^-1 48 h） Ang Ⅱ （ 100 nmol · L^-1） ＋ MG132 （0.05 μmol · L^-1） MG132 （0.05 μmol · L^-1） ,Ang 11 （100 nmol · L^-1 ） ＋ MG132 ＋ LiC1 （ 10 mmol · L^-1 ）, LiC1. Proteasome activitiy was detected by fluorescent peptide substrate. Cardiomyocyte surface area, ANF mRNA expression, and the rate of protein synthesis were observed as myocardial hypertrophy index. GSK-3, Akt, AMPKoL, and Histone3 （H3） were detected by Western Blot. The expression of GATA4 in the cytoplasm and nucleus was observed by im- munofluorescence. Results （1） Compared with the control group, myocardial ANF mRNA expression, the rate of protein synthesis and cell surface area were all increased in Ang H group. The chymotrypsin-like, trypsin-like and caspase-like activities of proteasome were all increased significantly. The phosphorylated level of both GSK-3α（ p- GSK-3α） （ Ser21 ） and GSK-3β （p-GSK-3β ） （Ser9） increased, i. e they were inactivated. （2） Compared with the Ang II group, myocardial ANF mRNA expression, the rate of protein synthesis and cell surface area were all decreased after proteasome inhibition. And p-GSK-3 （Ser21） and p-GSK-3β （Ser9） was respondingly decreased, （3） Proteasome inhibition also resulted in the decrease of p-Akt （Ser473） and p-AMPKa （Thr172）7 which in- creased in cardiomyocyte hypertrophy. Immunofluorescence showed that GATA4 was mainly distributed in the nu- cleus after Ang II treatment, while it was obviously increased in the cytoplasm after proteasome inhibition. After the GSK-3 inhibitor-LiC1 was given, the above indicators were reversed. （4） p-Histone3 was also increased in cardio- myocyte hypertrophy and MG132 reduced its level, but LiC1 treatment had no significant effect on its level. Con- clusion Proteasome inhibition reduces cardiomyocyte hypertrophy through increase of GSK-3a/b activity, which may be related with the decrease of Akt and AMPKa activities, and the decrease of nucleus location of GATA4, but p-histone3 is not involved.
基金the National Natural Science Foundation of China(NSFC,Grant No.31801459,31701520)Science and Technology General Projects of Fujian Province(2019J01393)Educational research project for young and middleaged teachers in Fujian Province(JT180116).
文摘Dihydromyricetin(DHM),as a bioactive flavanonol compound,is mainly found in“Tengcha”(Ampelopsis grossedentata)cultivated in south of China.This study aimed to investigate the anti-hyperglycemic and antidyslipidemic activities of DHM using type 2 diabetes mellitus(T2D)rats,which was induced by feeding with high fat and fructose diet for 42 days and intraperitoneal administration of streptozocin.Forty-eight freshlyweaned rats were randomly assigned into the negative control(Blank),low dose(100 mg/kg),medium dose(200 mg/kg),high dose(400 mg/kg),and positive(40 mg/kg,met)groups.Fasting blood glucose and body weight were measured at weekly interval.Oral glucose tolerance tests were performed on days 42.The results revealed that DHM possessed significant antihyperglycaemic and antihyperinsulinemic effects.Moreover,after the DHM treatment,p-Akt and p-AMPK expression was upregulated,and glycogen synthase kinase-3β(GSK-3β)expression was downregulated,indicating that the potential anti-diabetic mechanism of DHM might be due to the regulation of the AMPK/Akt/GSK-3βsignaling pathway.
基金supported by American Diabetes Association,American Heart Association,NIH NIEHS,NIH NIA,NIH NINDS,and NIH ARRA
文摘Throughout the globe,diabetes mellitus（DM） is increasing in incidence with limited therapies presently available to prevent or resolve the significant complications of this disorder.DM impacts multiple organs and affects all components of the central and peripheral nervous systems that can range from dementia to diabetic neuropathy.The mechanistic target of rapamycin（m TOR） is a promising agent for the development of novel regenerative strategies for the treatment of DM.m TOR and its related signaling pathways impact multiple metabolic parameters that include cellular metabolic homeostasis,insulin resistance,insulin secretion,stem cell proliferation and differentiation,pancreatic β-cell function,and programmed cell death with apoptosis and autophagy.m TOR is central element for the protein complexes m TOR Complex 1（m TORC1） and m TOR Complex 2（m TORC2） and is a critical component for a number of signaling pathways that involve phosphoinositide 3-kinase（PI 3-K）,protein kinase B（Akt）,AMP activated protein kinase（AMPK）,silent mating type information regulation 2 homolog 1（Saccharomyces cerevisiae）（SIRT1）,Wnt1 inducible signaling pathway protein 1（WISP1）,and growth factors.As a result,m TOR represents an exciting target to offer new clinical avenues for the treatment of DM and the complications of this disease.Future studies directed to elucidate the delicate balance m TOR holds over cellular metabolism and the impact of its broad signaling pathways should foster the translation of these targets into effective clinical regimens for DM.
基金Supported by the Zhengzhou Science and Technology Innovation Team Project(131PCXTD631)
文摘This study investigated the specific mechanism of knockdown of neuropeptide Y(NPY) in reducing obesity-induced insulin resistance in the white adipose tissue. Adeno-associated virus(AAV)-mediated RNAi was utilized to downregulate NPY expression in rats fed either regular chow or high fat diet. By investigating the differences in rat body weight and food intake, we assessed the effect of knockdown of NPY expression on insulin sensitivity and β-cell proliferation. Glucose consumption and 2-[3 H]DG uptake in 3 T3-L1 adipocytes were assessed to determine the molecular mechanisms. The results showed that knockdown of NPY expression in the dorsomedial hypothalamus(DMH) reduced obesity-induced insulin resistance, increased glucose consumption, and decreased 2-[3 H]DG uptake in 3 T3-L1 adipocytes via the PI3 K/Akt/GSK-3β signaling pathways and the NPY Y5 receptor.
