ABSTRACT
Obesity is increasingly prevalent globally, searching for therapeutic agents acting on adipose tissue is of great importance. Equisetin (EQST), a meroterpenoid isolated from a marine sponge-derived fungus, has been reported to display antibacterial and antiviral activities. Here, we revealed that EQST displayed anti-obesity effects acting on adipose tissue through inhibiting adipogenesis in vitro and attenuating HFD-induced obesity in mice, doing so without affecting food intake, blood pressure or heart rate. We demonstrated that EQST inhibited the enzyme activity of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), a therapeutic target of obesity in adipose tissue. Anti-obesity properties of EQST were all offset by applying excessive 11β-HSD1's substrates and 11β-HSD1 inhibition through knockdown in vitro or 11β-HSD1 knockout in vivo. In the 11β-HSD1 bypass model constructed by adding excess 11β-HSD1 products, EQST's anti-obesity effects disappeared. Furthermore, EQST directly bond to 11β-HSD1 protein and presented remarkable better intensity on 11β-HSD1 inhibition and better efficacy on anti-obesity than known 11β-HSD1 inhibitor. Therefore, EQST can be developed into anti-obesity candidate compound, and this study may provide more clues for developing higher effective 11β-HSD1 inhibitors.
ABSTRACT
Metagenomic sequencing provides a powerful tool for microbial research. However, traditional experimental DNA extraction process will inevitably mix with environmental microorganisms which float in the air. It is still unclear whether the mixed environmental microbial DNA will heavily affect the metagenomic results of samples with extremely low microbial content. In this study, we first collected environmental bacteria in the laboratory and quantified the mixed environmental microbial DNA content during DNA extraction based on a qPCR-based quantification assay. We then extracted DNA from pure water in order to determine the mixed microbial taxons during extraction under open environment. At last, we extracted total DNA from a skin sample in a Biosafety cabinet or under open laboratory environment, to assess the impact of the mixed environmental microorganisms on the metagenomic results. Our results showed that DNA extraction under open laboratory environment in Beijing region resulted in 28.9 pg contaminant, which may accout for 30% of total DNA amount from skin samples. Metagenomic analysis revealed that the main incorporated environmental taxons were Cutibacterium acnes and Escherichia coli. Tens of environmental bacteria were foisted in the skin DNA samples, which largely decreased the relative abundance of dominant species and thus deteriorated the result accuracy. Therefore, analyzing microbial composition of samples with extremely low DNA content should better performed under aseptic environment.
Subject(s)
DNA , DNA, Bacterial/genetics , Laboratories , Metagenomics , RNA, Ribosomal, 16S , Sequence Analysis, DNAABSTRACT
Obesity is a worldwide epidemic. Promoting browning of white adipose tissue (WAT) contributes to increased energy expenditure and hence counteracts obesity. Here we show that cordycepin (Cpn), a natural derivative of adenosine, increases energy expenditure, inhibits weight gain, improves metabolic profile and glucose tolerance, decreases WAT mass and adipocyte size, and enhances cold tolerance in normal and high-fat diet-fed mice. Cpn markedly increases the surface temperature around the inguinal WAT and turns the inguinal fat browner. Further investigations show that Cpn induces the development of brown-like adipocytes in inguinal and, to a less degree, epididymal WAT depots. Cpn also increases the expression of uncoupling protein 1 (UCP1) and other thermogenic genes in WAT and 3T3-L1 differentiated adipocytes, in which AMP-activated protein kinase (AMPK) plays an important role. Our results provide novel insights into the function of Cpn in regulating energy balance, and suggest a potential utility of Cpn in the treatment of obesity.
ABSTRACT
Syringaresinol-4---d-glucoside (SSG), a furofuran-type lignan, was found to modulate lipid and glucose metabolism through an activity screen of lipid accumulation and glucose consumption, and was therefore considered as a promising candidate for the prevention and treatment of metabolic disorder, especially in lipid and glucose metabolic homeostasis. In this study, the effects of SSG on lipogenesis and glucose consumption in HepG2 cells and C2C12 myotubes were further investigated. Treatment with SSG significantly inhibited lipid accumulation by oil red O staining and reduced the intracellular contents of total lipid, cholesterol and triglyceride in HepG2 cells. No effect was observed on cell viability in the MTT assay at concentrations of 0.1-10 μmol/L. SSG also increased glucose consumption by HepG2 cells and glucose uptake by C2C12 myotubes. Furthermore, real-time quantitative PCR revealed that the beneficial effects were associated with the down-regulation of sterol regulatory element-binding proteins-1c, -2 (), fatty acid synthase (), acetyl CoA carboxylase () and hydroxyl methylglutaryl CoA reductase (), and up-regulation of peroxisome proliferator-activated receptors alpha and gamma (and). SSG also significantly elevated transcription activity oftested by luciferase assay. These results suggest that SSG is an effective regulator of lipogenesis and glucose consumption and might be a candidate for further research in the prevention and treatment of lipid and glucose metabolic diseases.
ABSTRACT
The fruit of Pandanus tectorius (PTF) has a long history of use as a folk medicine to treat hyperlipidemia in Hainan province, South China. Our previous studies have shown that the n-butanol extract of PTF is rich in caffeoylquinic acids and has an adequate therapeutic effect on dyslipidemic animals induced by high-fat diet. In this work, seven caffeoylquinic acids isolated from PTF were screened for the lipid-lowering activity in HepG2 hepatoma cells. Oil-Red O staining, microscopy and intracellular triglyceride (TG) and total cholesterol (TC) quantification showed that 3-O-caffeoylquinic acid (3-CQA), 3, 5-di-O-caffeoylquinic acid (3,5-CQA), and 3,4,5-tri-O-caffeoylquinic acid (3,4,5-CQA) significantly inhibited lipid accumulation induced by oleic acid and decreased intracellular levels of TC and TG in a dose-dependent manner. These three caffeoylquinic acids showed no significant cytotoxicity at concentrations of 1 -50 μmol x L(-1) as determined by MTT assay. Realtime quantitative PCR revealed that 3-CQA and 3, 5-CQA significantly increased the expression of lipid oxidation-related genes PPARα, CPT-1 and ACOX1 while 3-CQA, 3, 5-CQA and 3,4,5-CQA decreased the expression of lipogenic genes SREBP-1c, SREBP-2, HMGR, ACC, FAS. Overall, 3-CQA, 3, 5-CQA and 3, 4, 5-CQA may be the principal hypolipidemic components in PTF which can decrease intracellular lipid accumulation through up-regulating the expression of lipid oxidative genes and down-regulating the expression of lipogenic genes.
ABSTRACT
Studying on marine natural products is a vibrant research area in the world. Due to their prevention and treatment effects on malignant tumor,cardiovascular disease and other major human diseases,marine natural products have become an important guidance to find the primary drugs. Recently,beneficial effects of marine natural products on treatment of metabolic syndrome related diseases have been intensively explored. Therefore,numbers of novel active products were found out and new mechanisms were revealed. This article reviews the research literature published after 2010 and summarizes the effects of marine natural products in metabolic syndrome related diseases,such as central obesity,insulin resistance,hyperlipidemia,hypertension and inflammation.