Combined use of astragalus polysaccharide and berberine attenuates insulin resistance in IR-HepG2 cells via regulation of the gluconeogenesis signaling pathway
ABSTRACT: Insulin resistance (IR) is likely to induce metabolic syndrome and type 2 diabetes mellitus (T2DM). Gluconeogenesis (GNG) is a complex metabolic process that may result in glucose generation from certain non-carbohydrate substrates. Chinese herbal medicine astragalus polysaccharides and berberine have been documented to ameliorate IR, and combined use of astragalus polysaccharide (AP) and berberine (BBR) are reported to synergistically produce an even better effect. However, what change may occur in the GNG signaling pathway of IR-HepG2 cells in this synergistic effect and whether AP-BBR attenuates IR by regulating the GNG signaling pathway remain unclear. For the first time, we discovered in this study that the optimal time of IR-HepG2 cell model formation was 48 hours after insulin intervention. AP-BBR attenuated IR in HepG2 cells and the optimal concentration was 10mg. AP-BBR reduced the intracellular H2O2 content with no significant effect on apoptosis of IR-HepG2 cells. In addition, a rapid change was observed in intracellular calcium current of the IR-HepG2 cell model, and AP-BBR intervention attenuated this change markedly. The gene sequencing results showed that the GNG signaling pathway was one of the signaling pathways of AP-BBR to attenuate IR in IR-Hepg2 cells. The expression of p-FoxO1Ser256 and PEPCK protein was increased and the expression of GLUT2 protein was decreased significantly in the IR-HepG2 cell model, and both of these effects could be reversed by AP-BBR intervention. AP-BBR attenuated IR in IR-HepG2 cells, probably by regulating the GNG signaling Pathway. Overall design: HepG2 cells (Cell Bank of the Chinese Academy of Sciences, Shanghai, China) were cultured in 1640 medium (Hyclone, Beijing, China) containing 10% fetal bovine serum (FBS, Hyclone, Beijing, China) and 1 × streptomycin in a 37 ℃ 5% CO2 saturated humidity incubator. The normally cultured HepG2 cell lines in log phase were centrifuged at 100grpm for 5 min, and 20000 cells/well were placed in a 96-well plate and incubated at 37°C.The experiment was performed in 24-h control group, 24-h model group, 36-h control group, 36-h model group, 48-h control group, 48-h model group, 72-h control group and 72-h model group. Insulin (Gibco, NY, USA) was diluted to a final concentration of 10-6 mol/L in complete medium. 200µl insulin preparation was added into each well for the model group and an equal amount of complete medium was added into each well for the control group. Culture was performed in a 37 ℃ 5% CO2 and saturated humidity incubator. The supernatant of the corresponding medium was collected according to the time point by centrifugation at 3000 r/min for 5 min and stored at-80 ℃ for use. RNA isolation, purification and quantification: Total RNA was isolated and purified using TRIzol reagent (Invitrogen, Carlsbad, CA, USA) following the manufacturer's procedure. The RNA amount and purity of each sample were quantified using NanoDrop ND-1000 (NanoDrop, Wilmington, DE, USA). The RNA integrity was assessed by Agilent 2100 with RIN number >7.0.cDNA Library Construction: Poly(A) RNA was purified from total RNA (5ug) using poly-T oligo-attached magnetic beads using two rounds of purification. Then, the poly(A) RNA was fragmented into small pieces using divalent cations under high temperature. Then the cleaved RNA fragments were reverse-transcribed to create the cDNA, which was subsequently used to synthesize U-labeled second-stranded DNAs with E. coli DNA polymerase I, RNase H and dUTP. An A-base was then added to the blunt ends of each strand, which were prepared for ligation to the indexed adapters. Each adapter contained a T-base overhang for ligating the adapter to the A-tailed fragmented DNA. Single- or dual-index adapters were ligated to the fragments, and size selection was performed with AMPureXP beads. After the heat-labile UDG enzyme treatment of the U-labeled second-stranded DNAs, the ligated products were amplified by PCR under the following conditions: initial denaturation at 95℃ for 3 min, 8 cycles of denaturation at 98℃ for 15 sec, annealing at 60℃ for 15 sec, extension at 72℃ for 30 sec, and then final extension at 72℃ for 5 min. The mean insert size for the final cDNA library was 300 bp (±50 bp). Finally, 150bp paired-end sequencing was performed on an Illumina Hiseq 4000 (LC Bio, China) following the vendor's recommended protocol.Pathway enrichment analysis: Using the DAVID database and mouse genome as background control, the differentially expressed genes were analyzed by gene ontology under "FunctionalAnnotation Chart" functional module. The differentially expressed genes were divided into three categories according to their functions: the biological process, the cell component and the molecular function. Pathway analysis was carried out by KEGG analysis function.
Project description:Insulin resistance (IR) is likely to induce metabolic syndrome and type 2 diabetes mellitus (T2DM). Gluconeogenesis (GNG) is a complex metabolic process that may result in glucose generation from certain non-carbohydrate substrates. Chinese herbal medicine astragalus polysaccharides and berberine have been documented to ameliorate IR, and combined use of astragalus polysaccharide (AP) and berberine (BBR) are reported to synergistically produce an even better effect. However, what change may occur in the GNG signaling pathway of IR-HepG2 cells in this synergistic effect and whether AP-BBR attenuates IR by regulating the GNG signaling pathway remain unclear. For the first time, we discovered in this study that the optimal time of IR-HepG2 cell model formation was 48 h after insulin intervention. AP-BBR attenuated IR in HepG2 cells and the optimal concentration was 10 mg. AP-BBR reduced the intracellular H2O2 content with no significant effect on apoptosis of IR-HepG2 cells. In addition, a rapid change was observed in intracellular calcium current of the IR-HepG2 cell model, and AP-BBR intervention attenuated this change markedly. The gene sequencing results showed that the GNG signaling pathway was one of the signaling pathways of AP-BBR to attenuate IR in IR-Hepg2 cells. The expression of p-FoxO1Ser256 and PEPCK protein was increased, and the expression of GLUT2 protein was decreased significantly in the IR-HepG2 cell model, and both of these effects could be reversed by AP-BBR intervention. AP-BBR attenuated IR in IR-HepG2 cells, probably by regulating the GNG signaling Pathway.
Project description:Background:Radix Astragali (Astragalus membranaceus var. mongholicus (Bunge)) and Coptis chinensis (Coptis chinensis var. angustiloba) are two commonly prescribed traditional Chinese herbs for diabetes. Astragalus Polysaccharide (AP) and Berberine (BBR) are active ingredients of these two herbs respectively and they are scientifically proved to have immunomodulatory and anti-inflammatory effects. They are also known for their antidiabetic potential by ameliorating insulin resistance (IR). AP and BBR have shown different advantages in treating diabetes according to previous reports. However, very few studies focus on the combined activities of the two potential antidiabetic ingredients. In this study, we discovered that reactive oxygen species (ROS) accumulated in IR-hepG2 cells and APBBR can decrease ROS level in model group significantly. We conjectured that APBBR can ameliorate IR in hepG2 cells by decreasing ROS level. In order to verify this hypothesis, we obtained phenotype and transcriptome information of IR-HepG2 cells and explore the underlying mechanism of the combination of AP and BBR(APBBR) activity on the relationship between ROS change in IR at whole-transcriptome level, so as to shed new light to efficacy and application of APBBR in treating diabetes. Methods:The IR cell model was established with high-level insulin intervention. Glucose content, HepG2 cell viability as well as ROS level was detected to study the effect of IR-hepG2 cell phenotype. Unbiased genome-wide RNA sequencing was used to investigate alterations in experimental groups. Then, GO and KEGG functional enrichment was performed to explore the function and pathway of target genes. Venn analysis found out the differentially expressed lncRNAs that had close relationship with IR and ROS. Finally, we screened out candidate lncRNAs and these target genes to construct interaction network of differentiated lncRNA-miRNA-mRNA by according to the principle of competitive endogenous RNA (ceRNA). Results:The biochemical experiments showed that APBBR administration could improve the proliferation activity of IR-HepG2 cells and decrease ROS level in model cells. The GO and KEGG functional enrichment analyses demonstrated several mRNAs remarkably enriched in biological processes and signaling pathways related to ROS production and IR progression. Interaction network suggest that APBBR ameliorates IR in HepG2 cells by regulating the expression of multiple genes and activating relevant signaling pathway to decrease ROS level. Thus, we demonstrated that APBBR ameliorated IR in hepG2 cells via the ROS-dependent pathway.
Project description:<b>Objective:</b> Recent studies demonstrate circulating serum spexin levels are reduced in obesity or type 2 diabetes mellitus (T2DM) patients and may play a role in glucose metabolism. The mechanism underlying is not known. In this study, we explore whether spexin has a role in insulin resistance and hepatic glucose metabolism. <b>Methods:</b> The correlation between serum spexin levels and the homeostasis model assessment of insulin resistance (HOMA-IR) was studied in newly diagnosed T2DM patients. After intraperitoneal injection of exogenous spexin for 8 weeks, the effect of spexin on exogenous glucose infusion rates (GIR), and hepatic glucose production (HGP) were assessed by extended hyperinsulinemic-euglycemic clamp in high-fat-diet (HFD)-induced rats. Glucose concentration with CRISPR/Cas9-mediated disruption of spexin expression in HepG2 cells culture was observed. Expression of transcription factors (Forkhead box O1, FoxO1 and peroxisome proliferator-activated receptor gamma coactivator 1-alpha, PGC-1α) and key enzymes (G-6-Pase and PEPCK) of gluconeogenesis pathway were observed in vitro and in vivo. <b>Results:</b> The serum spexin level was significantly low in newly diagnosed T2DM patients as compared with healthy patients and significantly negatively correlated with the HOMA-IR values. Exogenous spexin treatment resulted in weight loss and decrease of HOMA-IR value in high-fat-diet (HFD)-induced rats. The exogenous glucose infusion rates (GIR) were higher in the HFD + spexin group than that in the HFD group (358 ± 32 vs. 285 ± 24 μmol/kg/min, <i>P</i> < 0.05). Steady-state hepatic glucose production (HGP) was also suppressed by ~50% in the HFD + spexin group as compared with that in the HFD group. Furthermore, spexin inhibited gluconeogenesis in dose-dependent and time-dependent manner in the insulin-resistant cell model. CRISPR/Cas9-mediated knockdown of spexin in HepG2 cells activated gluconeogenesis. Moreover, spexin was shown regulating gluconeogenesis by inhibiting FoxO1/PGC-1α pathway, and key gluconeogenic enzymes, (PEPCK and G-6-Pase) in both HFD-induced rats and insulin-resistant cells. <b>Conclusions:</b> Spexin plays an important role in insulin resistance in HFD-induced rats and insulin-resistant cells. Regulation of the effects of spexin on insulin resistance may hold therapeutic value for metabolic diseases.
Project description:Objectives:Untreated acromegaly is a nature model for unveiling the diabetogenic effects of GH. CGMS can uncover more glucose profile of acromegaly. This study aimed to evaluate the insulin resistance (IR), β-cell function, and glycemic spectrum of patients with newly diagnosed acromegaly with normal glucose tolerance (NGT). Methods:This study was conducted in Huashan Hospital from January 2015 to February 2019. Eight newly diagnosed acromegalic patients without history of diabetes and eight age- and gender-matched healthy subjects were enrolled. All participants underwent oral glucose tolerance test (OGTT) and 72 h continuous glucose monitoring (CGM). Parameters on β-cell function and IR were calculated. Mean blood glucose (MBG) in 24 hours was adopted for the evaluation of the glycemic level, and standard deviation of blood glucose (SDBG) and mean amplitude of glycemic excursion (MAGE) were used for glucose fluctuation. Results:HbA1c in the acromegaly group was significantly higher than in the control. During OGTT, glucose peaked at 60 min in acromegaly and at 30 min in controls. After glucose load, the acromegaly group had significantly higher insulin levels than controls, especially in 120 min and 180 min. Both insulin sensitivity index and disposal index after glucose load of acromegaly were significantly lower than those of controls. Moreover, acromegalic subjects had significantly higher MBG than controls. Conclusions:The newly diagnosed acromegalic patients with NGT were characterized by IR and impaired β-cell function after glucose load. CGM showed that MBG of NGT acromegaly patients was higher than that of normal people.
Project description:BACKGROUND:To examine the effect of Tai Chi Chuan (TCC) practice on glucose and lipid metabolism and related hormones in TCC practitioners. METHODS:Twenty-one TCC practitioners and nineteen healthy controls were included in this study. Classical Yang's TCC was practiced by the TCC practitioners. The percentage changes in serum total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), serum glucose (SG), serum insulin, serum insulin level, homeostatic model assessment of insulin resistance (HOMA-IR), log(HOMA-IR), quantitative insulin sensitivity check index (QUICKI), and serum endothelin-1 (ET-1) before and 30 min after resting or TCC practice were compared between healthy controls and TCC practitioners. RESULTS:Before TCC or resting, the serum insulin level, HOMA-IR, and log(HOMA-IR) of the TCC practitioners were significantly lower than those of healthy subjects, whereas the QUICKI of the TCC practitioners was significantly higher than that of healthy subjects. Thirty min after TCC practice, the %TC, %HDL-C, %QUICKI, and %ET-1 were all significantly decreased, whereas the %SG, %serum insulin, and %HOMA-IR were significantly increased in the TCC group as compared to the control group 30 min after resting. CONCLUSIONS:The serum glucose, insulin level and insulin resistance were enhanced, whereas the cholesterol, HDL-C and ET-1 levels were reduced 30 min after TCC practice. The mechanism underlying these effects of TCC 30 min after TCC is not clear yet.
Project description:Insulin resistance contributes to several disorders including type 2 diabetes and cardiovascular diseases. Carpachromene is a natural active compound that inhibits α-glucosidase enzyme. The aim of the present study is to investigate the potential activity of carpachromene on glucose consumption, metabolism and insulin signalling in a HepG2 cells insulin resistant model. A HepG2 insulin resistant cell model (HepG2/IRM) was established. Cell viability assay of HepG2/IRM cells was performed after carpachromene/metformin treatment. Glucose concentration and glycogen content were determined. Western blot analysis of insulin receptor, IRS1, IRS2, PI3k, Akt, GSK3, FoxO1 proteins after carpachromene treatment was performed. Phosphoenolpyruvate carboxykinase (PEPCK) and hexokinase (HK) enzymes activity was also estimated. Viability of HepG2/IRM cells was over 90% after carpachromene treatment at concentrations 6.3, 10, and 20 µg/mL. Treatment of HepG2/IRM cells with carpachromene decreased glucose concentration in a concentration- and time-dependant manner. In addition, carpachromene increased glycogen content of HepG2/IRM cells. Moreover, carpachromene treatment of HepG2/IRM cells significantly increased the expression of phosphorylated/total ratios of IR, IRS1, PI3K, Akt, GSK3, and FoxO1 proteins. Furthermore, PEPCK enzyme activity was significantly decreased, and HK enzyme activity was significantly increased after carpachromene treatment. The present study examined, for the first time, the potential antidiabetic activity of carpachromene on a biochemical and molecular basis. It increased the expression ratio of insulin receptor and IRS1 which further phosphorylated/activated PI3K/Akt pathway and phosphorylated/inhibited GSK3 and FoxO1 proteins. Our findings revealed that carpachromene showed central molecular regulation of glucose metabolism and insulin signalling via IR/IRS1/ PI3K/Akt/GSK3/FoxO1 pathway.
Project description:Bile acids (BA) are potent metabolic regulators influenced by diet. We studied effects of isoenergetic increases in the dietary protein and cereal-fiber contents on circulating BA and insulin resistance (IR) in overweight and obese adults. Randomized controlled nutritional intervention (18 weeks) in 72 non-diabetic participants (overweight/obese: 29/43) with at least one further metabolic risk factor. Participants were group-matched and allocated to four isoenergetic supplemented diets: control; high cereal fiber (HCF); high-protein (HP); or moderately increased cereal fiber and protein (MIX). Whole-body IR and insulin-mediated suppression of hepatic endogenous glucose production were measured using euglycaemic-hyperinsulinemic clamps with [6-62H2] glucose infusion. Circulating BA, metabolic biomarkers, and IR were measured at 0, 6, and 18 weeks. Under isoenergetic conditions, HP-intake worsened IR in obese participants after 6 weeks (M-value: 3.77?±?0.58 vs. 3.07?±?0.44?mg/kg/min, p?=?0.038), with partial improvement back to baseline levels after 18 weeks (3.25?±?0.45?mg/kg/min, p?=?0.089). No deleterious effects of HP-intake on IR were observed in overweight participants. HCF-diet improved IR in overweight participants after 6 weeks (M-value 4.25?±?0.35 vs. 4.81?±?0.31?mg/kg/min, p?=?0.016), but did not influence IR in obese participants. Control and MIX diets did not influence IR. HP-induced, but not HCF-induced changes in IR strongly correlated with changes of BA profiles. MIX-diet significantly increased most BA at 18 weeks in obese, but not in overweight participants. BA remained unchanged in controls. Pooled BA concentrations correlated with fasting fibroblast growth factor-19 (FGF-19) plasma levels (r?=?0.37; p?=?0.003). Higher milk protein intake was the only significant dietary predictor for raised total and primary BA in regression analyses (total BA, p?=?0.017; primary BA, p?=?0.011). Combined increased intake of dietary protein and cereal fibers markedly increased serum BA concentrations in obese, but not in overweight participants. Possible mechanisms explaining this effect may include compensatory increases of the BA pool in the insulin resistant, obese state; or defective BA transport.
Project description:AIM:To test the efficacy of a proprietary nutraceutical combination in reducing insulin resistance associated with the metabolic syndrome (MetS). METHODS:Sixty-four patients with MetS followed at a tertiary outpatient clinic were randomly assigned to receive either placebo or a proprietary nutraceutical combination (AP) consisting of berberine, policosanol and red yeast rice, in a prospective, double-blind, placebo-controlled study. Evaluations were performed at baseline and after 18 wk of treatment. The homeostasis model assessment of insulin resistance (HOMA-IR) index was the primary outcome measure. Secondary endpoints included lipid panel, blood glucose and insulin fasting, after a standard mixed meal and after an oral glucose tolerance test (OGTT), flow-mediated dilation (FMD), and waist circumference. RESULTS:Fifty nine patients completed the study, 2 withdrew because of adverse effects. After 18 wk there was a significant reduction in the HOMA-IR index in the AP group compared with placebo (?HOMA respectively -0.6 ± 1.2 vs 0.4 ± 1.9; P < 0.05). Total and low density lipoprotein cholesterol also significantly decreased in the treatment arm compared with placebo (?low density lipoprotein cholesterol -0.82 ± 0.68 vs -0.13 ± 0.55 mmol/L; P < 0.001), while triglycerides, high density lipoprotein cholesterol, and the OGTT were not affected. In addition, there were significant reductions in blood glucose and insulin after the standard mixed meal, as well as an increase in FMD (?FMD 1.9 ± 4.2 vs 0 ± 1.9 %; P < 0.05) and a significant reduction in arterial systolic blood pressure in the AP arm. CONCLUSION:This short-term study shows that AP has relevant beneficial effects on insulin resistance and many other components of MetS.
Project description:The aim of this study was to deeper investigate the mechanisms through which ENPP1, a negative modulator of insulin receptor (IR) activation, plays a role on insulin signaling, insulin secretion and eventually glucose metabolism. ENPP1 cDNA (carrying either K121 or Q121 variant) was transfected in HepG2 liver-, L6 skeletal muscle- and INS1E beta-cells. Insulin-induced IR-autophosphorylation (HepG2, L6, INS1E), Akt-Ser(473), ERK1/2-Thr(202)/Tyr(204) and GSK3-beta Ser(9) phosphorylation (HepG2, L6), PEPCK mRNA levels (HepG2) and 2-deoxy-D-glucose uptake (L6) was studied. GLUT 4 mRNA (L6), insulin secretion and caspase-3 activation (INS1E) were also investigated. Insulin-induced IR-autophosphorylation was decreased in HepG2-K, L6-K, INS1E-K (20%, 52% and 11% reduction vs. untransfected cells) and twice as much in HepG2-Q, L6-Q, INS1E-Q (44%, 92% and 30%). Similar data were obtained with Akt-Ser(473), ERK1/2-Thr(202)/Tyr(204) and GSK3-beta Ser(9) in HepG2 and L6. Insulin-induced reduction of PEPCK mRNA was progressively lower in untransfected, HepG2-K and HepG2-Q cells (65%, 54%, 23%). Insulin-induced glucose uptake in untransfected L6 (60% increase over basal), was totally abolished in L6-K and L6-Q cells. GLUT 4 mRNA was slightly reduced in L6-K and twice as much in L6-Q (13% and 25% reduction vs. untransfected cells). Glucose-induced insulin secretion was 60% reduced in INS1E-K and almost abolished in INS1E-Q. Serum deficiency activated caspase-3 by two, three and four folds in untransfected INS1E, INS1E-K and INS1E-Q. Glyburide-induced insulin secretion was reduced by 50% in isolated human islets from homozygous QQ donors as compared to those from KK and KQ individuals. Our data clearly indicate that ENPP1, especially when the Q121 variant is operating, affects insulin signaling and glucose metabolism in skeletal muscle- and liver-cells and both function and survival of insulin secreting beta-cells, thus representing a strong pathogenic factor predisposing to insulin resistance, defective insulin secretion and glucose metabolism abnormalities.
Project description:<i>Background and objectives:</i> Obstructive sleep apnea (OSA) is closely associated with insulin resistance (IR) and is an independent risk factor for incident type 2 diabetes mellitus (T2DM). Most studies evaluate the correlation between OSA and IR in only obese or T2DM patients. Therefore, we tried to investigate the effect of OSA on metabolic syndrome and IR in the general healthy male population. <i>Materials and Methods:</i> 184 subjects who visited a preventive health examination program were recruited for this study. All subjects received overnight polysomnography by a portable device (Watch-PAT 200). We examined several metabolic parameters and a homeostasis model of assessment for insulin resistance index (HOMA-IR). The subjects were divided into three groups by AHI (Apnea-hyponea index): normal group (AHI < 5), mild OSA group (5 ≤ AHI < 15), and moderate-severe OSA group (AHI ≥ 15). They were also divided into two groups according to minimum oxygen saturation: low group, Min-SpO2 < 88%; and high group, Min-SpO2 ≥ 88%. <i>Results:</i> Parameters of metabolic syndrome, including waist circumference, systolic and diastolic blood pressure, triglyceride, and high-density lipoprotein cholesterol showed significant differences among the AHI groups. Furthermore, HOMA-IR showed significant differences among the AHI groups. Those parameters, including metabolic syndrome and HOMA-IR, also showed differences between Min-SpO2 groups. <i>Conclusions:</i> In summary, this study helps confirm that AHI is associated with HOMA-IR in the general male population. Furthermore, the severity of AHI correlated with the parameters of metabolic syndrome. Therefore, AHI might be an indicator for evaluating both T2DM and metabolic syndrome, even in the general male population.