Nonalcoholic fatty liver disease (NAFLD) is the most prevalent cause of chronic liver disease worldwide. NAFLD is considerably more frequent in patients with type 2 diabetes mellitus (T2DM) than in the general populat...Nonalcoholic fatty liver disease (NAFLD) is the most prevalent cause of chronic liver disease worldwide. NAFLD is considerably more frequent in patients with type 2 diabetes mellitus (T2DM) than in the general population and is also more severe histologically in this group. Sodium-glucose co-transporter-2 (SGLT2) inhibitors, the newest class of antidiabetic agents, appear to represent a promising option for the management of NAFLD in patients with T2DM. In a number of studies, treatment with SGLT2 inhibitors resulted in a reduction in hepatic steatosis and in transaminase levels. However, existing studies are small, their follow-up period was short and none evaluated the effects of SGLT2 inhibitors on liver histology. Accordingly, larger studies are needed to verify these preliminary results and define the role of SGLT2 inhibitors in the treatment of NAFLD in patients with T2DM.展开更多
AIM:To investigate the effects of the somatostatin analogue,octreotide,on maltose and sucrase activities and expression of glucose transporter type 2(GLUT2) in obese rat intestinal mucosa.METHODS:We divided 49 Sprague...AIM:To investigate the effects of the somatostatin analogue,octreotide,on maltose and sucrase activities and expression of glucose transporter type 2(GLUT2) in obese rat intestinal mucosa.METHODS:We divided 49 Sprague-Dawley rats into a group of 31 high fat diet-induced obese rats and a group of 18 normal controls.The obese rats were separated into an octreotide treated group of 16 rats and an obese group of 15.The intervention group was injected with octreotide at 40μg/kg body weight every 12 h for 8 d.Rat body weight was measured weekly to calculate Lee's index.After euthanization,maltase and sucrase activities in the small intestine were measuredby activity assays,and the fasting plasma glucose level was measured.The expression of GLUT2 in small intestinal mucosa was analyzed by immunohistochem-istry,reverse transcriptase polymerase chain reaction and Western blotting assays.RESULTS:Body weight,Lee's index,fasting plasma glucose level,maltase activity in small intestinal mucosa,mucosa and apical GLUT2,GLUT2 mRNA and protein expression levels were all significantly higher in the obese group than in the normal control group(605.61±141.00 vs 378.54±111.75,337.61 ±10.82 vs 318.73±20.10,8.60±1.38 vs 7.33± 0.70,156.01±58.81 vs 50.43±30.49,390 744.2 ±62 469.21 vs 170 546.50±50 646.14,26 740.18 ±3809.60 vs 354.98±57.19,0.26±0.11 vs 0.07 ±0.02,and 2.08±0.59 vs 1.27±0.38,respectively,all P<0.01).Sucrase activity did not differ between the two groups.Octreotide intervention significantly decreased the body weight and fasting plasma glucose level of obese rats(508.27±94.39 vs 605.61±141.00,7.58±1.51 vs 8.60±1.38,respectively,all P<0.05).The intestinal mucosa and apical GLUT2,expression of GLUT2 mRNA and protein were also significantly lower in the octreotide intervention group than in the obese group(269 975.2 ±53 730.94 vs 390 744.2±62 469.21,3758.06± 364.51 vs 26 740.18±3809.60,0.08±0.02 vs 0.26± 0.11,and 1.31±0.27 vs 2.08±0.59,respectively,all P<0.01).CONCLUSION:High fat dietinduced obesity is associated with elevated intestinal maltase activity,GLUT2 expression,and permanent apical GLUT2 in the small intestinal mucosa of rats.Octreotide can inhibit these effects.展开更多
Objective To reveal the effects and related mechanisms of chlorogenic acid(CGA)on intestinal glucose homeostasis.Methods Forty male Sprague-Dawley rats were randomly and equally divided into four groups:normal chow(NC...Objective To reveal the effects and related mechanisms of chlorogenic acid(CGA)on intestinal glucose homeostasis.Methods Forty male Sprague-Dawley rats were randomly and equally divided into four groups:normal chow(NC),high-fat diet(HFD),HFD with low-dose CGA(20 mg/kg,HFD-LC),and HFD with high-dose CGA(90 mg/kg,HFD-HC).The oral glucose tolerance test was performed,and fast serum insulin(FSI)was detected using an enzyme-linked immunosorbent assay.The m RNA expression levels of glucose transporters(Sglt-1 and Glut-2)and proglucagon(Plg)in different intestinal segments(the duodenum,jejunum,ileum,and colon)were analyzed using quantitative real-time polymerase chain reaction.SGLT-1 protein and the morphology of epithelial cells in the duodenum and jejunum was localized by using immunofluorescence.Results At both doses,CGA ameliorated the HFD-induced body weight gain,maintained FSI,and increased postprandial 30-min glucagon-like peptide 1 secretion.High-dose CGA inhibited the HFD-induced elevation in Sglt-1 expression.Both CGA doses normalized the HFD-induced downregulation of Glut-2 and elevated the expression of Plg in all four intestinal segments.Conclusion An HFD can cause a glucose metabolism disorder in the rat intestine and affect body glucose homeostasis.CGA can modify intestinal glucose metabolism by regulating the expression of intestinal glucose transporters and Plg,thereby controlling the levels of blood glucose and insulin to maintain glucose homeostasis.展开更多
Dietary flavonoids are abundant in natural plants and possess multiple pharmacological and nutritional activities.In this study,apigenin,luteolin,and baicalein were chosen to evaluate their anti-diabetic effect in hig...Dietary flavonoids are abundant in natural plants and possess multiple pharmacological and nutritional activities.In this study,apigenin,luteolin,and baicalein were chosen to evaluate their anti-diabetic effect in high-glucose and dexamethasone induced insulin-resistant(IR)HepG2 cells.All flavonoids improves the glucose consumption and glycogen synthesis abilities in IR-HepG2 cells via activating glucose transporter protein 4(GLUT4)and phosphor-glycogen synthase kinase(GSK-3β).These fl avonoids signifi cantly inhibited the production of reactive oxygen species(ROS)and advanced glycation end-products(AGEs),which were closely related to the suppression of the phosphorylation form of NF-κB and P65.The expression levels of insulin receptor substrate-1(IRS-1),insulin receptor substrate-2(IRS-2)and phosphatidylinositol 3-kinase(PI3K)/protein kinase B(Akt)pathway in IR-HepG2 cells were all partially activated by the fl avonoids,with variable effects.Furthermore,the intracellular metabolic conditions of the fl avonoids were also evaluated.展开更多
BACKGROUND:The glucose transporter-1(Glut-1),a key ratelimiting factor in the transport and metabolism of glucose in cancer cells,is over-expressed in many human cancer cells and this overexpression is correlated with...BACKGROUND:The glucose transporter-1(Glut-1),a key ratelimiting factor in the transport and metabolism of glucose in cancer cells,is over-expressed in many human cancer cells and this overexpression is correlated with poor biological behavior. The increased levels of Glut-1 expression in hepatocellular carcinoma(HCC)cells functionally affect tumorigenicity.This study was undertaken to investigate effects of suppressing Glut-1 by an antisense oligodeoxynucleotide(AS-ODN)on the growth of human hepatocellular carcinoma(HepG-2)cells. METHODS:We used AS-ODN targeting against the Glut-1 gene in a HepG-2 cell line.There were four experimental groups: empty pcDNA3.1 vector(mock transfection),pcDNA3.1-anti-Glut(+),pcDNA3.1-Glut(+),and non-transfected HepG-2 cells. The Glut-1 mRNA expression was detected by RT-PCR and the Glut-1 protein expression by Western blotting after cell culture, and the glucose uptake was detected after glucose stimulation in each group. RESULTS:Compared with non-transfected HepG-2 or Glut-1 pcDNA3.1,a down-regulation of Glut-1 mRNA in HepG-2 cells transfected with anti-Glut-1 pcDNA3.1 was noted(P<0.05).Glut-1 protein in HepG-2 cells transfected with Glut-1 AS-ODN was decreased compared with non-transfected HepG-2,Glut-1 pcDNA3.1,or empty vectors. Glucose uptake by the HepG-2 cells transfected with AS-ODN was decreased at 1 hour after glucose stimulation.CONCLUSIONS:The application of Glut-1 AS-ODN can down-regulate the expression of Glut-1 at mRNA and protein,and inhibit glucose uptake partially in HepG-2 cells.The Glut-1 gene maybe a potential therapeutic target for HCC.展开更多
BACKGROUND Colorectal cancer(CRC)is a worldwide problem,which has been associated with changes in diet and lifestyle pattern.As a result of colonic fermentation of dietary fibres,short chain free fatty acids are gener...BACKGROUND Colorectal cancer(CRC)is a worldwide problem,which has been associated with changes in diet and lifestyle pattern.As a result of colonic fermentation of dietary fibres,short chain free fatty acids are generated which activate free fatty acid receptors(FFAR)2 and 3.FFAR2 and FFAR3 genes are abundantly expressed in colonic epithelium and play an important role in the metabolic homeostasis of colonic epithelial cells.Earlier studies point to the involvement of FFAR2 in colorectal carcinogenesis.AIM To understand the role of short chain FFARs in CRC.METHODS Transcriptome analysis console software was used to analyse microarray data from CRC patients and cell lines.We employed short-hairpin RNA mediated down regulation of FFAR2 and FFAR3 genes,which was validated using quantitative real time polymerase chain reaction.Assays for glucose uptake and cyclic adenosine monophosphate(cAMP)generation was done along with immunofluorescence studies to study the effects of FFAR2/FFAR3 knockdown.For measuring cell proliferation,we employed real time electrical impedancebased assay available from xCELLigence.RESULTS Microarray data analysis of CRC patient samples showed a significant down regulation of FFAR2 gene expression.This prompted us to study the FFAR2 in CRC.Since,FFAR3 shares significant structural and functional homology with FFAR2,we knocked down both these receptors in CRC cell line HCT 116.These modified cell lines exhibited higher proliferation rate and were found to have increased glucose uptake as well as increased level of glucose transporter 1.Since,FFAR2 and FFAR3 signal through G protein subunit(Gαi),knockdown of these receptors was associated with increased cAMP.Inhibition of protein kinase A(PKA)did not alter the growth and proliferation of these cells indicating a mechanism independent of cAMP/PKA pathway.CONCLUSION Our results suggest role of FFAR2/FFAR3 genes in increased proliferation of colon cancer cells via enhanced glucose uptake and exclude the role of PKA mediated cAMP signalling.Alternate pathways could be involved that would ultimately result in increased cell proliferation as a result of down regulated FFAR2/FFAR3 genes.This study paves the way to understand the mechanism of action of short chain FFARs in CRC.展开更多
文摘Nonalcoholic fatty liver disease (NAFLD) is the most prevalent cause of chronic liver disease worldwide. NAFLD is considerably more frequent in patients with type 2 diabetes mellitus (T2DM) than in the general population and is also more severe histologically in this group. Sodium-glucose co-transporter-2 (SGLT2) inhibitors, the newest class of antidiabetic agents, appear to represent a promising option for the management of NAFLD in patients with T2DM. In a number of studies, treatment with SGLT2 inhibitors resulted in a reduction in hepatic steatosis and in transaminase levels. However, existing studies are small, their follow-up period was short and none evaluated the effects of SGLT2 inhibitors on liver histology. Accordingly, larger studies are needed to verify these preliminary results and define the role of SGLT2 inhibitors in the treatment of NAFLD in patients with T2DM.
基金Supported by Grants from the National Natural Sciences Foundation of China,No.30870919Sichuan Provincial Department of Science and Technology,No.2010SZ0176
文摘AIM:To investigate the effects of the somatostatin analogue,octreotide,on maltose and sucrase activities and expression of glucose transporter type 2(GLUT2) in obese rat intestinal mucosa.METHODS:We divided 49 Sprague-Dawley rats into a group of 31 high fat diet-induced obese rats and a group of 18 normal controls.The obese rats were separated into an octreotide treated group of 16 rats and an obese group of 15.The intervention group was injected with octreotide at 40μg/kg body weight every 12 h for 8 d.Rat body weight was measured weekly to calculate Lee's index.After euthanization,maltase and sucrase activities in the small intestine were measuredby activity assays,and the fasting plasma glucose level was measured.The expression of GLUT2 in small intestinal mucosa was analyzed by immunohistochem-istry,reverse transcriptase polymerase chain reaction and Western blotting assays.RESULTS:Body weight,Lee's index,fasting plasma glucose level,maltase activity in small intestinal mucosa,mucosa and apical GLUT2,GLUT2 mRNA and protein expression levels were all significantly higher in the obese group than in the normal control group(605.61±141.00 vs 378.54±111.75,337.61 ±10.82 vs 318.73±20.10,8.60±1.38 vs 7.33± 0.70,156.01±58.81 vs 50.43±30.49,390 744.2 ±62 469.21 vs 170 546.50±50 646.14,26 740.18 ±3809.60 vs 354.98±57.19,0.26±0.11 vs 0.07 ±0.02,and 2.08±0.59 vs 1.27±0.38,respectively,all P<0.01).Sucrase activity did not differ between the two groups.Octreotide intervention significantly decreased the body weight and fasting plasma glucose level of obese rats(508.27±94.39 vs 605.61±141.00,7.58±1.51 vs 8.60±1.38,respectively,all P<0.05).The intestinal mucosa and apical GLUT2,expression of GLUT2 mRNA and protein were also significantly lower in the octreotide intervention group than in the obese group(269 975.2 ±53 730.94 vs 390 744.2±62 469.21,3758.06± 364.51 vs 26 740.18±3809.60,0.08±0.02 vs 0.26± 0.11,and 1.31±0.27 vs 2.08±0.59,respectively,all P<0.01).CONCLUSION:High fat dietinduced obesity is associated with elevated intestinal maltase activity,GLUT2 expression,and permanent apical GLUT2 in the small intestinal mucosa of rats.Octreotide can inhibit these effects.
基金supported by the National Natural Science foundation of China(No.31071531)the Scientific Research Fund of the Hunan Provincial Education Department(No.14A071)the China National Tobacco Corp Hunan Branch(15-17Aa04)
文摘Objective To reveal the effects and related mechanisms of chlorogenic acid(CGA)on intestinal glucose homeostasis.Methods Forty male Sprague-Dawley rats were randomly and equally divided into four groups:normal chow(NC),high-fat diet(HFD),HFD with low-dose CGA(20 mg/kg,HFD-LC),and HFD with high-dose CGA(90 mg/kg,HFD-HC).The oral glucose tolerance test was performed,and fast serum insulin(FSI)was detected using an enzyme-linked immunosorbent assay.The m RNA expression levels of glucose transporters(Sglt-1 and Glut-2)and proglucagon(Plg)in different intestinal segments(the duodenum,jejunum,ileum,and colon)were analyzed using quantitative real-time polymerase chain reaction.SGLT-1 protein and the morphology of epithelial cells in the duodenum and jejunum was localized by using immunofluorescence.Results At both doses,CGA ameliorated the HFD-induced body weight gain,maintained FSI,and increased postprandial 30-min glucagon-like peptide 1 secretion.High-dose CGA inhibited the HFD-induced elevation in Sglt-1 expression.Both CGA doses normalized the HFD-induced downregulation of Glut-2 and elevated the expression of Plg in all four intestinal segments.Conclusion An HFD can cause a glucose metabolism disorder in the rat intestine and affect body glucose homeostasis.CGA can modify intestinal glucose metabolism by regulating the expression of intestinal glucose transporters and Plg,thereby controlling the levels of blood glucose and insulin to maintain glucose homeostasis.
基金supported by National Natural Science Foundation of China(32072212)Multi-Year Research Grant of University of Macao(MYRG2018-00169-ICMS)+5 种基金Science and Technology Development Fund of Macao(FDCT)(0098/2020/A)MICINN supporting the Ramón y Cajal grant for M.A.Prieto(RYC-201722891)Jianbo Xiao(RYC2020-030365-I)Xunta de Galicia supporting the Axudas Conecta Peme,the IN852A 2018/58 Neuro Food Project,the program EXCELENCIA-ED431F 2020/12the pre-doctoral grants of P.García-Oliveira(ED481A-2019/295)to Ibero-American Program on Science and Technology(CYTED-AQUA-CIBUS,P317RT0003).
文摘Dietary flavonoids are abundant in natural plants and possess multiple pharmacological and nutritional activities.In this study,apigenin,luteolin,and baicalein were chosen to evaluate their anti-diabetic effect in high-glucose and dexamethasone induced insulin-resistant(IR)HepG2 cells.All flavonoids improves the glucose consumption and glycogen synthesis abilities in IR-HepG2 cells via activating glucose transporter protein 4(GLUT4)and phosphor-glycogen synthase kinase(GSK-3β).These fl avonoids signifi cantly inhibited the production of reactive oxygen species(ROS)and advanced glycation end-products(AGEs),which were closely related to the suppression of the phosphorylation form of NF-κB and P65.The expression levels of insulin receptor substrate-1(IRS-1),insulin receptor substrate-2(IRS-2)and phosphatidylinositol 3-kinase(PI3K)/protein kinase B(Akt)pathway in IR-HepG2 cells were all partially activated by the fl avonoids,with variable effects.Furthermore,the intracellular metabolic conditions of the fl avonoids were also evaluated.
文摘BACKGROUND:The glucose transporter-1(Glut-1),a key ratelimiting factor in the transport and metabolism of glucose in cancer cells,is over-expressed in many human cancer cells and this overexpression is correlated with poor biological behavior. The increased levels of Glut-1 expression in hepatocellular carcinoma(HCC)cells functionally affect tumorigenicity.This study was undertaken to investigate effects of suppressing Glut-1 by an antisense oligodeoxynucleotide(AS-ODN)on the growth of human hepatocellular carcinoma(HepG-2)cells. METHODS:We used AS-ODN targeting against the Glut-1 gene in a HepG-2 cell line.There were four experimental groups: empty pcDNA3.1 vector(mock transfection),pcDNA3.1-anti-Glut(+),pcDNA3.1-Glut(+),and non-transfected HepG-2 cells. The Glut-1 mRNA expression was detected by RT-PCR and the Glut-1 protein expression by Western blotting after cell culture, and the glucose uptake was detected after glucose stimulation in each group. RESULTS:Compared with non-transfected HepG-2 or Glut-1 pcDNA3.1,a down-regulation of Glut-1 mRNA in HepG-2 cells transfected with anti-Glut-1 pcDNA3.1 was noted(P<0.05).Glut-1 protein in HepG-2 cells transfected with Glut-1 AS-ODN was decreased compared with non-transfected HepG-2,Glut-1 pcDNA3.1,or empty vectors. Glucose uptake by the HepG-2 cells transfected with AS-ODN was decreased at 1 hour after glucose stimulation.CONCLUSIONS:The application of Glut-1 AS-ODN can down-regulate the expression of Glut-1 at mRNA and protein,and inhibit glucose uptake partially in HepG-2 cells.The Glut-1 gene maybe a potential therapeutic target for HCC.
文摘BACKGROUND Colorectal cancer(CRC)is a worldwide problem,which has been associated with changes in diet and lifestyle pattern.As a result of colonic fermentation of dietary fibres,short chain free fatty acids are generated which activate free fatty acid receptors(FFAR)2 and 3.FFAR2 and FFAR3 genes are abundantly expressed in colonic epithelium and play an important role in the metabolic homeostasis of colonic epithelial cells.Earlier studies point to the involvement of FFAR2 in colorectal carcinogenesis.AIM To understand the role of short chain FFARs in CRC.METHODS Transcriptome analysis console software was used to analyse microarray data from CRC patients and cell lines.We employed short-hairpin RNA mediated down regulation of FFAR2 and FFAR3 genes,which was validated using quantitative real time polymerase chain reaction.Assays for glucose uptake and cyclic adenosine monophosphate(cAMP)generation was done along with immunofluorescence studies to study the effects of FFAR2/FFAR3 knockdown.For measuring cell proliferation,we employed real time electrical impedancebased assay available from xCELLigence.RESULTS Microarray data analysis of CRC patient samples showed a significant down regulation of FFAR2 gene expression.This prompted us to study the FFAR2 in CRC.Since,FFAR3 shares significant structural and functional homology with FFAR2,we knocked down both these receptors in CRC cell line HCT 116.These modified cell lines exhibited higher proliferation rate and were found to have increased glucose uptake as well as increased level of glucose transporter 1.Since,FFAR2 and FFAR3 signal through G protein subunit(Gαi),knockdown of these receptors was associated with increased cAMP.Inhibition of protein kinase A(PKA)did not alter the growth and proliferation of these cells indicating a mechanism independent of cAMP/PKA pathway.CONCLUSION Our results suggest role of FFAR2/FFAR3 genes in increased proliferation of colon cancer cells via enhanced glucose uptake and exclude the role of PKA mediated cAMP signalling.Alternate pathways could be involved that would ultimately result in increased cell proliferation as a result of down regulated FFAR2/FFAR3 genes.This study paves the way to understand the mechanism of action of short chain FFARs in CRC.