Citrus aurantium L. dry extracts promote C/ebpβ expression and improve adipocyte differentiation in 3T3-L1 cells

A Combination of Polymethoxyflavones from Citrus sinensis and Prenylflavonoids from Humulus lupulus Counteracts IL-1β-Induced Differentiated Caco-2 Cells Dysfunction via a Modulation of NF-κB/Nrf2 Activation

We here investigated the anti-inflammatory activity of a polymethoxylated flavone-containing fraction (PMFF) from Citrus sinensis and of a prenylflavonoid-containing one (PFF) from Humulus lupulus, either alone or in combination (MIX). To this end, an in vitro model of inflammatory bowel disease (IBD), consisting of differentiated, interleukin (IL)-1β-stimulated Caco-2 cells, was employed. We demonstrated that non-cytotoxic concentrations of either PMFF or PFF or MIX reduced nitric oxide (NO) production while PFF and MIX, but not PMFF, also inhibited prostaglandin E2 release. Coherently, MIX suppressed both inducible NO synthase and cyclooxygenase-2 over-expression besides NF-κB activation. Moreover, MIX increased nuclear factor erythroid 2-related factor 2 (Nrf2) activation, heme oxygenase-1 expression, restoring GSH and reactive oxygen and nitrogen species (RONs) levels. Remarkably, these effects with MIX were stronger than those produced by PMFF or PFF alone. Noteworthy, nobiletin (NOB) and xanthohumol (XTM), two of the most represented phytochemicals in PMFF and PFF, respectively, synergistically inhibited RONs production. Overall, our results demonstrate that MIX enhances the anti-inflammatory and anti-oxidative effects of the individual fractions in a model of IBD, via a mechanism involving modulation of NF-κB and Nrf2 signalling. Synergistic interactions between NOB and XTM emerge as a relevant aspect underlying this evidence.

ZMAT3 hypomethylation contributes to early senescence of preadipocytes from healthy first-degree relatives of type 2 diabetics

Senescence of adipose precursor cells (APC) impairs adipogenesis, contributes to the age-related subcutaneous adipose tissue (SAT) dysfunction, and increases risk of type 2 diabetes (T2D). First-degree relatives of T2D individuals (FDR) feature restricted adipogenesis, reflecting the detrimental effects of APC senescence earlier in life and rendering FDR more vulnerable to T2D. Epigenetics may contribute to these abnormalities but the underlying mechanisms remain unclear. In previous methylome comparison in APC from FDR and individuals with no diabetes familiarity (CTRL), ZMAT3 emerged as one of the top-ranked senescence-related genes featuring hypomethylation in FDR and associated with T2D risk. Here, we investigated whether and how DNA methylation changes at ZMAT3 promote early APC senescence. APC from FDR individuals revealed increases in multiple senescence markers compared to CTRL. Senescence in these cells was accompanied by ZMAT3 hypomethylation, which caused ZMAT3 upregulation. Demethylation at this gene in CTRL APC led to increased ZMAT3 expression and premature senescence, which were reverted by ZMAT3 siRNA. Furthermore, ZMAT3 overexpression in APC determined senescence and activation of the p53/p21 pathway, as observed in FDR APC. Adipogenesis was also inhibited in ZMAT3-overexpressing APC. In FDR APC, rescue of ZMAT3 methylation through senolytic exposure simultaneously downregulated ZMAT3 expression and improved adipogenesis. Interestingly, in human SAT, aging and T2D were associated with significantly increased expression of both ZMAT3 and the P53 senescence marker. Thus, DNA hypomethylation causes ZMAT3 upregulation in FDR APC accompanied by acquisition of the senescence phenotype and impaired adipogenesis, which may contribute to FDR predisposition for T2D.

Transcriptomics analysis of Daheng broilers reveals that PLIN2 regulates chicken preadipocyte proliferation, differentiation and apoptosis

BACKGROUND

Intramuscular fat content, an important meat quality trait, strongly affects flavor, juiciness, and tenderness. Sex hormones regulate lipid metabolism, and female hormones stimulate fat deposition, thereby making the female chickens always fatter than males. In this study, the effect of sex on IMF deposition was screened following transcriptomics in chickens.

METHODS AND RESULTS

Results confirmed significantly higher IMF content of 150-day female chickens as compared to the male chickens. The female chickens manifested higher serum TG, LDL-C, and VLDL, and significantly lower HDL-C contents than male chickens. Moreover, differential expression of genes involved in lipid metabolism were obtained in the muscle and liver between female and male chicken, which could partly interpret the possible reasons for the sex-mediated differences of IMF content. Cellular results revealed that inhibition of PLIN2 significantly inhibited chicken preadipocyte proliferation and induces apoptosis of preadipocytes, as well as promoted adipocyte differentiation.

CONCLUSIONS

According to our results, PLIN2 may be considered as a molecular marker for poultry meat quality and applying this gene in early breed selection.

Pharmacopuncture of Taraxacum platycarpum extract reduces localized fat by regulating the lipolytic pathway

Localized fat deposits are associated with health and aesthetic problems that mainly affect a large proportion of individuals. Recently, bioactive constituents of TP have been reported to affect lipid metabolism. In this study, we performed a network pharmacological analysis to assume potential lipolytic effects of TP and investigated the actual lipolytic effects of TP extract injection on local body fat and its underlying mechanism. Using the genes related to active compounds of TP, the network was constructed. Through the Functional Enrichment Analysis, Lipid Metabolism and Fatty Acid Metabolism were expected to be affiliated with the network, which implied possible lipolytic effects of TP. On the comparison between TP network and Obesity-related Gene Sets, about three-fourths of elements were in common with the gene sets, which indicated a high relevance between TP and obesity. Based on the genes in lipolysis-related pathways, Perilipin, CGI-58, ATGL, HSL and MGL were selected to identify the actual lipolytic effects of TP. TP injection reduced the inguinal fat weight. Also, the diameter of the adipocytes was decreased by the TP treatment in HFD-induced obese mice. In addition, TP suppressed lipid accumulation in differentiated 3T3-L1 adipocytes. Moreover, because the expression of Perilipin was increased, CGI-58, ATGL, HSL and MGL were markedly decreased. Furthermore, glycerol release was down-regulated by the TP treatment. TP exerted its lipolytic effects by regulating the lipolysis machinery through stimulation of lipases. Based on the present findings, TP is expected to be a potent component of injection lipolysis for removing localized body fat.

Adipocyte precursor cells from first degree relatives of type 2 diabetic patients feature changes in hsa-mir-23a-5p, -193a-5p, and -193b-5p and insulin-like growth factor 2 expression

First-degree relatives (FDRs) of type 2 diabetics (T2D) feature dysfunction of subcutaneous adipose tissue (SAT) long before T2D onset. miRNAs have a role in adipocyte precursor cells (APC) differentiation and in adipocyte identity. Thus, impaired miRNA expression may contribute to SAT dysfunction in FDRs. In the present work, we have explored changes in miRNA expression associated with T2D family history which may affect gene expression in SAT APCs from FDRs. Small RNA-seq was performed in APCs from healthy FDRs and matched controls and omics data were validated by qPCR. Integrative analyses of APC miRNome and transcriptome from FDRs revealed down-regulated hsa-miR-23a-5p, -193a-5p and -193b-5p accompanied by up-regulated Insulin-like Growth Factor 2 (IGF2) gene which proved to be their direct target. The expression changes in these marks were associated with SAT adipocyte hypertrophy in FDRs. APCs from FDRs further demonstrated reduced capability to differentiate into adipocytes. Treatment with IGF2 protein decreased APC adipogenesis, while over-expression of hsa-miR-23a-5p, -193a-5p and -193b-5p enhanced adipogenesis by IGF2 targeting. Indeed, IGF2 increased the Wnt Family Member 10B gene expression in APCs. Down-regulation of the three miRNAs and IGF2 up-regulation was also observed in Peripheral Blood Leukocytes (PBLs) from FDRs. In conclusion, APCs from FDRs feature a specific miRNA/gene profile, which associates with SAT adipocyte hypertrophy and appears to contribute to impaired adipogenesis. PBL detection of this profile may help in identifying adipocyte hypertrophy in individuals at high risk of T2D.

Citrus aurantium L. Dry Extracts Ameliorate Adipocyte Differentiation of 3T3-L1 Cells Exposed to TNFα by Down-Regulating miR-155 Expression

Citrus aurantium L. dry extracts (CAde) improve adipogenesis in vitro. These effects are dependent from an early modulation of CCAAT/enhancer-binding protein beta (C/Ebpβ) expression and cyclic Adenosine Monophosphate (cAMP) response element-binding protein (CREB) activation. C/Ebpβ and Creb are also targets of miR-155. This study investigated whether CAde regulates miR-155 expression in the early stages of adipogenesis and whether it ameliorates adipocyte differentiation of cells exposed to tumor necrosis factor-alpha (TNFα). Adipogenic stimuli (AS) were performed in 3T3-L1 pre-adipocytes treated with CAde, TNFα, or both. Gene and miRNA expression were determined by quantitative real-time PCR. Adipogenesis was evaluated by Oil-Red O staining. CAde treatment enhanced AS effects during the early adipogenesis phases by further down-regulating miR-155 expression and increasing both C/Ebpβ and Creb mRNA and protein levels. At variance, TNFα inhibited 3T3-L1 adipogenesis and abolished AS effects on miR-155, C/Ebpβ, and Creb expression. However, in cells exposed to TNFα, CAde improved adipocyte differentiation and restored the AS effects on miRNA and gene expression at early time points. In conclusion, this study identified miR-155 down-regulation as part of the mechanism through which CAde enhances adipogenesis of pre-adipocytes in vitro. Furthermore, it provides evidence of CAde efficacy against TNFα negative effects on adipogenesis.

The Effect of Methanolic Valeriana officinalis Root Extract on Adipocyte Differentiation and Adiponectin Production in 3T3-L1 Adipocytes

Adipose tissue is an endocrine organ and its endocrine function is closely associated with type 2 diabetes mellitus. Valeriana officinalis (Valerian) exerts some physiological effects; however, its influence on adipocytes remains unclear. We investigated the effect of methanolic Valerian root extract (Vale) on 3T3-L1 adipocytes. Vale (1, 10, and 100 μg/mL) dose-dependently promoted adipocyte differentiation with increasing lipid accumulation. In addition, Vale significantly increased the mRNA levels in genes associated with adipocyte differentiation, including peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer-binding protein α , and adipocyte protein 2, in dose-dependent manner. Vale also significantly enhanced mRNA and protein levels in adiponectin. A PPARγ antagonist assay and a PPARγ binding assay revealed that Vale-induced increased adipocyte differentiation and adiponectin production were partly associated with direct binding to PPARγ. Valerenic acid, a characteristic component in Valerian, also demonstrated the ability to induce adipocyte differentiation and adiponectin secretion, suggesting that it is one of the functional components in Vale.

Bitter Orange (Citrus aurantium Linné) Improves Obesity by Regulating Adipogenesis and Thermogenesis through AMPK Activation

Obesity is a global health threat. Herein, we evaluated the underlying mechanism of anti-obese features of bitter orange (Citrus aurantium Linné, CA). Eight-week-administration of CA in high fat diet-induced obese C57BL/6 mice resulted in a significant decrease of body weight, adipose tissue weight and serum cholesterol. In further in vitro studies, we observed decreased lipid droplets in CA-treated 3T3-L1 adipocytes. Suppressed peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer binding protein alpha indicated CA-inhibited adipogenesis. Moreover, CA-treated primary cultured brown adipocytes displayed increased differentiation associated with elevation of thermogenic factors including uncoupling protein 1 and PPARγ coactivator 1 alpha as well. The effects of CA in both adipocytes were abolished in AMP-activated protein kinase alpha (AMPKα)-suppressed environments, suggesting the anti-adipogenic and pro-thermogenic actions of CA were dependent on AMPKα pathway. In conclusion, our results suggest CA as a potential anti-obese agent which regulates adipogenesis and thermogenesis via AMPKα.

Polyphenolic Extract from Tarocco (Citrus sinensis L. Osbeck) Clone "Lempso" Exerts Anti-Inflammatory and Antioxidant Effects via NF-kB and Nrf-2 Activation in Murine Macrophages

Citrus fruits are often employed as ingredients for functional drinks. Among Citrus, the variety, “Lempso”, a typical hybrid of the Calabria region (Southern Italy), has been reported to possess superior antioxidant activity when compared to other common Citrus varieties. For these reasons, the aim of this study is to investigate in vitro the nutraceutical value of the Tarocco clone, “Lempso”, highlighting its anti-inflammatory and antioxidant potential. A post-column 2,2′-diphenyl-1-picrylhydrazyl (DPPH•) radical scavenging assay for the screening of antioxidant compounds in these complex matrices was developed. Subsequently, polyphenolic extract was tested on a murine macrophage cell line under inflammatory conditions. The extract resulted was able to significantly inhibit nitric oxide (NO) and cytokine release and inducible nitric oxide synthase (iNOS) and cycloxygenase-2 (COX-2) expression. The inhibition of these pro-inflammatory factors was associated to Nuclear factor-kB (NF-kB) inhibition. Our results also indicate an anti-oxidant potential of the extract as evidenced by the inhibition of reactive oxygen species (ROS) release and by the activation of the nuclear factor E2-related factor-2 (Nrf-2) pathway in macrophages. The obtained results highlight the anti-inflammatory and antioxidant potential of Lempso extract and its potential use, as a new ingredient for the formulation of functional beverages with high nutraceutical value, providing health benefits to consumers.