Mangiferin Decreases Plasma Free Fatty Acids through Promoting Its Catabolism in Liver by Activation of AMPK

Mangiferin has been shown to have the effect of improving dyslipidemia. Plasma free fatty acids (FFA) are closely associated with blood lipid metabolism as well as many diseases including metabolic syndrome. This study is to investigate whether mangiferin has effects on FFA metabolism in hyperlipidemic rats. Wistar rats were fed a high-fat diet and administered mangiferin simultaneously for 6 weeks. Mangiferin (50, 100, 150 mg/kg BW) decreased dose-dependently FFA and triglycerides (TG) levels in plasma, and their accumulations in liver, but increased the β-hydroxybutyrate levels in both plasma and liver of hyperlipidemic rats. HepG2 cells were treated with oleic acid (OA, 0.2 mmol/L) to simulate the condition of high level of plasma FFA in vitro, and were treated with different concentrations of mangiferin simultaneously for 24 h. We found that mangiferin significantly increased FFA uptake, significantly decreased intracellular FFA and TG accumulations in HepG2 cells. Mangiferin significantly increased AMP-activated protein kinase (AMPK) phosphorylation and its downstream proteins involved in fatty acid translocase (CD36) and carnitine palmitoyltransferase 1 (CPT1), but significantly decreased acyl-CoA: diacylgycerol acyltransferase 2 (DGAT2) expression and acetyl-CoA carboxylase (ACC) activity by increasing its phosphorylation level in both in vivo and in vitro studies. Furthermore, these effects were reversed by Compound C, an AMPK inhibitor in HepG2 cells. For upstream of AMPK, mangiferin increased AMP/ATP ratio, but had no effect on LKB1 phosphorylation. In conclusion, mangiferin decreased plasma FFA levels through promoting FFA uptake and oxidation, inhibiting FFA and TG accumulations by regulating the key enzymes expression in liver through AMPK pathway. Therefore, mangiferin is a possible beneficial natural compound for metabolic syndrome by improving FFA metabolism

Mangiferin Improved Palmitate-Induced-Insulin Resistance by Promoting Free Fatty Acid Metabolism in HepG2 and C2C12 Cells via PPARα: Mangiferin Improved Insulin Resistance

Elevated free fatty acid (FFA) is a key risk factor for insulin resistance (IR). Our previous studies found that mangiferin could decrease serum FFA levels in obese rats induced by a high-fat diet. Our research was to determine the effects and mechanism of mangiferin on improving IR by regulating FFA metabolism in HepG2 and C2C12 cells. The model was used to quantify PA-induced lipid accumulation in the two cell lines treated with various concentrations of mangiferin simultaneously for 24 h. We found that mangiferin significantly increased insulin-stimulated glucose uptake, via phosphorylation of protein kinase B (P-AKT), glucose transporter 2 (GLUT2), and glucose transporter 4 (GLUT4) protein expressions, and markedly decreased glucose content, respectively, in HepG2 and C2C12 cells induced by PA. Mangiferin significantly increased FFA uptake and decreased intracellular FFA and triglyceride (TG) accumulations. The activity of the peroxisome proliferator-activated receptor α (PPARα) protein and its downstream proteins involved in fatty acid translocase (CD36) and carnitine palmitoyltransferase 1 (CPT1) and the fatty acid β-oxidation rate corresponding to FFA metabolism were also markedly increased by mangiferin in HepG2 and C2C12 cells. Furthermore, the effects were reversed by siRNA-mediated knockdown of PPARα. Mangiferin ameliorated IR by increasing the consumption of glucose and promoting the FFA oxidation via the PPARα pathway in HepG2 and C2C12 cells

Effects of mangiferin on the proteins expression of FFA metabolism including AMPK, CD36, CPT1, ACC and DGAT2 in liver of hyperlipidemic rats.

<p>Wistar rats were divided randomly into five groups (n = 10 per group): control group (fed an AIN-93G diet); hyperlipidemia group (fed a high-fat diet); mangiferin-supplemented groups, fed the high-fat diet and different doses of mangiferin (50, 100, 150 mg/kg BW/d). The experiment lasted for 6 weeks, and the liver was taken for western blot analysis. (A) AMPK phosphorylation level. (B) CD36 expression on cell membrane. (C) CPT1 expression in mitochondrion. (D) ACC level and activity. (E) DGAT2 expression. * P<0.05 compared with hyperlipidemic group.</p

Effect of mangiferin on fasting metabolic variables at 6 weeks in hyperlipemic rats.

<p>Data are means ± SD (n = 10),</p>#<p><i>P</i><0.05</p>##<p><i>P</i><0.01 indicate statistically significant differences when compared with control group.</p><p>*<i>P</i><0.05 and</p><p>**<i>P</i><0.01 indicate statistically significant differences when compared with hyperlipidemia group.</p

HepG2 cells were incubated with 0.2 mmol/L OA only or with different concentrations of mangiferin (12.5, 25, 50, 100 µmol/L) simultaneously for 24 h.

<p>Proteins were isolated from the cell lysates and analyzed by western blot analysis for AMPK (A), CD36 (B), CPT1 (C), ACC (D) and DGAT (E) expressions. The experiments were repeated 3 times. Data are presented as means ± SD (n = 3). ^*<i>P</i><0.05 compared with only OA stimulation group.</p

Effects of compound C on mangiferin induced FFA uptake, intracellular FFA, TG and FFA metabolism proteins expression in HepG2 cells.

<p>HepG2 cells were pretreated 1 h with compound C, an AMPK inhibitor, and then treated with 100 µmol/L mangiferin and 0.2 mmol/L OA for 24 h. OA in medium (To assess the uptake of OA) (A), intracellular OA (A), intracellular TG (A) and proteins expression of FFA metabolism including AMPK (B), ACC (B), CD36 (B), CPT1 (B) and DGAT2 (B) were determined by western blot method. The experiments were repeated 3 times. Data are presented as means ± SD (n = 3). ^*<i>P</i><0.05 and ^**<i>P</i><0.01 compared with only OA stimulation group.</p

Effects of mangiferin on the ratio of AMP to ATP and LKB1 protein expression in HepG2 cells.

<p>HepG2 cells were incubated to 0.2 mmol/L oleic acid only or with different concentrations of mangiferin (12.5, 25, 50, 100 µmol/L) simultaneously for 24 h. The ratio of AMP to ATP was detected by HPLC (A). The LKB1 protein expression was carried out by western blot analysis (B). The experiments were repeated 3 times. Data are presented as means ± SD (n = 3). ^*<i>P</i><0.05 compared with only OA stimulation group.</p

Additional file 1: of Free fatty acids profile among lean, overweight and obese non-alcoholic fatty liver disease patients: a case – control study

Supplementary Information. (DOCX 61 kb

Genome-wide analysis of methylation in giant pandas with cataract by methylation-dependent restriction-site associated DNA sequencing (MethylRAD).

The giant panda (Ailuropoda melanoleuca) is a native species to China. They are rare and endangered and are regarded as the 'national treasure' and 'living fossil' in China. For the time being, there are only about 2500 giant pandas in the world. Therefore, we still have to do much more efforts to protect the giant pandas. In captive wildlife, the cataract incidence of mammalian always increases with age. Currently, in China, the proportion of elderly giant pandas who suffering from cataract has reached 20%. The eye disorder thus has a strong influence on the physical health and life quality of the elderly giant pandas. To discover the genes associated with the pathogenesis of cataract in the elderly giant panda and achieve the goal of early assessment and diagnosis of cataract in giant pandas during aging, we performed whole genome methylation sequencing in 3 giant pandas with cataract and 3 healthy giant pandas using methylation-dependent restriction-site associated DNA sequencing (MethylRAD). In the present study, we obtained 3.62M reads, on average, for each sample, and identified 116 and 242 differentially methylated genes (DMGs) between the two groups under the context of CCGG and CCWGG on genome, respectively. Further KEGG and GO enrichment analyses determined a total of 110 DMGs that are involved in the biological functions associated with pathogenesis of cataract. Among them, 6 DMGs including EEA1, GARS, SLITRK4, GSTM3, CASP3, and EGLN3 have been linked with cataract in old age

Calcium supplementation increases circulating cholesterol by reducing its catabolism via GPER and TRPC1-dependent pathway in estrogen deficient women

Background: Limited studies have addressed the effects of calcium supplementation (CaS) on serum total cholesterol (TC) in postmenopausal women and the results are inconclusive. Moreover, the potential mechanisms through which CaS regulates cholesterol metabolism in the absence of estrogen are still sealed for the limitation of human being study. Methods: Cross-sectional survey, animal and in vitro experiments were conducted to investigate the effect of CaS on endogenous cholesterol metabolism in estrogen de\ufb01ciency and identify its potential mechanisms. Ovariectomized rats were used to mimic estrogen de\ufb01ciency. In vitro, HepG2 cell line was exposed to estradiol and/or calcium treatment. Results: We demonstrated that CaS signi\ufb01cantly increased serum TC and the risk of hypercholesterolemia and myocardial infarction in postmenopausal women. Increased serum TC in estrogen de\ufb01ciency was caused mainly by decreased cholesterol catabolism rather than increased synthesis. This was mediated by reduced 7\u3b1-hydroxylase resulting from increased liver intracellular Ca\ub2\u207a concentrations, reduced intracellular basal cAMP and subsequent up-regulation of SREBP-1c and SHP expression. Estrogen had a protective role in preventing CaS-induced TC increase by activating the G-protein coupled estrogen receptor, which mediated the estrogen effect through the transient receptor potential canonical 1 cation channel. Conclusions: CaS increases endogenous serum TC via decreasing hepatic cholesterol catabolism in estrogen de\ufb01ciency. G-protein coupled estrogen receptor is shown to be a key target in mediating CaS-induced TC increase. CaS should be monitored for the prevention of serum TC increase during menopause.Peer reviewed: YesNRC publication: Ye