Caenorhabditis elegans as a Screening Model for Probiotics with Properties against Metabolic Syndrome.

There is a growing need to develop new approaches to prevent and treat diseases related to metabolic syndromes, including obesity or type 2 diabetes, that focus on the different factors involved in the pathogenesis of these diseases. Due to the role of gut microbiota in the regulation of glucose and insulin homeostasis, probiotics with beneficial properties have emerged as an alternative therapeutic tool to ameliorate metabolic diseases-related disturbances, including fat excess or inflammation. In the last few years, different strains of bacteria, mainly lactic acid bacteria (LAB) and species from the genus Bifidobacterium, have emerged as potential probiotics due to their anti-obesogenic and/or anti-diabetic properties. However, in vivo studies are needed to demonstrate the mechanisms involved in these probiotic features. In this context, Caenorhabditis elegans has emerged as a very powerful simple in vivo model to study the physiological and molecular effects of probiotics with potential applications regarding the different pathologies of metabolic syndrome. This review aims to summarize the main studies describing anti-obesogenic, anti-diabetic, or anti-inflammatory properties of probiotics using C. elegans as an in vivo research model, as well as providing a description of the molecular mechanisms involved in these activities.

Plant miR8126-3p and miR8126-5p Decrease Lipid Accumulation through Modulation of Metabolic Genes in a Human Hepatocyte Model That Mimics Steatosis.

Plant-based food interventions are promising therapeutic approaches for non-alcoholic fatty liver disease (NAFLD) treatment, and microRNAs (miRNAs) have emerged as functional bioactive components of dietary plants involved in cross-kingdom communication. Deeper investigations are needed to determine the potential impact of plant miRNAs in NAFLD. This study aimed to identify plant miRNAs that could eventually modulate the expression of human metabolic genes and protect against the progression of hepatic steatosis. Plant miRNAs from the miRBase were used to predict human target genes, and miR8126-3p and miR8126-5p were selected as candidates for their potential role in inhibiting glucose and lipid metabolism-related genes. Human HepG2 cells were transfected with plant miRNA mimics and then exposed to a mixture of oleic and palmitic acids to mimic steatosis. miR8126-3p and miR8126-5p transfections inhibited the expression of the putative target genes QKI and MAPKAPK2, respectively, and had an impact on the expression profile of key metabolic genes, including PPARA and SREBF1. Quantification of intrahepatic triglycerides revealed that miR8126-3p and miR8126-5p attenuated lipid accumulation. These findings suggest that plant miR8126-3p and miR8126-5p would induce metabolic changes in human hepatocytes eventually protecting against lipid accumulation, and thus, they could be potential therapeutic tools for preventing and alleviating lipid accumulation.

Glucose-lowering effects of a synbiotic combination containing Pediococcus acidilactici in C. elegans and mice.

AIMS/HYPOTHESIS: Modulation of gut microbiota has emerged as a promising strategy to treat or prevent the development of different metabolic diseases, including type 2 diabetes and obesity. Previous data from our group suggest that the strain Pediococcus acidilactici CECT9879 (pA1c) could be an effective probiotic for regulating glucose metabolism. Hence, the objectives of this study were to verify the effectiveness of pA1c on glycaemic regulation in diet-induced obese mice and to evaluate whether the combination of pA1c with other normoglycaemic ingredients, such as chromium picolinate (PC) and oat ß-glucans (BGC), could increase the efficacy of this probiotic on the regulation of glucose and lipid metabolism. METHODS: Caenorhabditis elegans was used as a screening model to describe the potential synbiotic activities, together with the underlying mechanisms of action. In addition, 4-week-old male C57BL/6J mice were fed with a high-fat/high-sucrose diet (HFS) for 6 weeks to induce hyperglycaemia and obesity. Mice were then divided into eight groups (n=12 mice/group) according to dietary supplementation: control-diet group; HFS group; pA1c group (1010 colony-forming units/day); PC; BGC; pA1c+PC+BGC; pA1c+PC; and pA1c+BGC. Supplementations were maintained for 10 weeks. Fasting blood glucose was determined and an IPGTT was performed prior to euthanasia. Fat depots, liver and other organs were weighed, and serum biochemical variables were analysed. Gene expression analyses were conducted by real-time quantitative PCR. Sequencing of the V3-V4 region of the 16S rRNA gene from faecal samples of each group was performed, and differential abundance for family, genera and species was analysed by ALDEx2R package. RESULTS: Supplementation with the synbiotic (pA1c+PC+BGC) counteracted the effect of the high glucose by modulating the insulin-IGF-1 signalling pathway in C. elegans, through the reversal of the glucose nuclear localisation of daf-16. In diet-induced obese mice, all groups supplemented with the probiotic significantly ameliorated glucose tolerance after an IPGTT, demonstrating the glycaemia-regulating effect of pA1c. Further, mice supplemented with pA1c+PC+BGC exhibited lower fasting blood glucose, a reduced proportion of visceral adiposity and a higher proportion of muscle tissue, together with an improvement in the brown adipose tissue in comparison with the HFS group. Besides, the effect of the HFS diet on steatosis and liver damage was normalised by the synbiotic. Gene expression analyses demonstrated that the synbiotic activity was mediated not only by modulation of the insulin-IGF-1 signalling pathway, through the overexpression of GLUT-1 and GLUT-4 mediators, but also by a decreased expression of proinflammatory cytokines such as monocyte chemotactic protein-1. 16S metagenomics demonstrated that the synbiotic combinations allowed an increase in the concentration of P. acidilactici, together with improvements in the intestinal microbiota such as a reduction in Prevotella and an increase in Akkermansia muciniphila. CONCLUSIONS/INTERPRETATION: Our data suggest that the combination of pA1c with PC and BGC could be a potential synbiotic for blood glucose regulation and may help to fight insulin resistance, diabetes and obesity.

Nutritional Interventions with Bacillus coagulans Improved Glucose Metabolism and Hyperinsulinemia in Mice with Acute Intermittent Porphyria.

Acute intermittent porphyria (AIP) is a metabolic disorder caused by mutations in the porphobilinogen deaminase (PBGD) gene, encoding the third enzyme of the heme synthesis pathway. Although AIP is characterized by low clinical penetrance (~1% of PBGD mutation carriers), patients with clinically stable disease report chronic symptoms and frequently show insulin resistance. This study aimed to evaluate the beneficial impact of nutritional interventions on correct carbohydrate dysfunctions in a mouse model of AIP that reproduces insulin resistance and altered glucose metabolism. The addition of spores of Bacillus coagulans in drinking water for 12 weeks modified the gut microbiome composition in AIP mice, ameliorated glucose tolerance and hyperinsulinemia, and stimulated fat disposal in adipose tissue. Lipid breakdown may be mediated by muscles burning energy and heat dissipation by brown adipose tissue, resulting in a loss of fatty tissue and improved lean/fat tissue ratio. Probiotic supplementation also improved muscle glucose uptake, as measured using Positron Emission Tomography (PET) analysis. In conclusion, these data provide a proof of concept that probiotics, as a dietary intervention in AIP, induce relevant changes in intestinal bacteria composition and improve glucose uptake and muscular energy utilization. Probiotics may offer a safe, efficient, and cost-effective option to manage people with insulin resistance associated with AIP.

Genetic and epigenetic nutritional interactions influencing obesity risk and adiposity outcomes.

PURPOSE OF REVIEW: This article aims to critically overview the current interplay of genetic/epigenetic factors and several nutritional aspects influencing obesity susceptibility and adiposity outcomes for obesity management and weight status monitoring. RECENT FINDINGS: Single nucleotide polymorphisms located in or near genes participating in energy homeostasis, fatty acid metabolism, appetite control, brain regulation, and thermogenesis have been associated with body composition measures (body weight, body mass index, waist circumference, body fat percentage, and visceral adipose tissue) depending on nutrient intakes, dietary patterns, and eating behaviors. Moreover, studies analyzing interactions between the epigenome and dietary intakes in relation to adiposity outcomes are reported. The main epigenetic mechanisms include methylation levels of promoter sequences, telomere length, and micro-ribonucleic acid expression profiles, whereas covalent histone modifications remain less studied. SUMMARY: Exploring potential interactions between the genetic/epigenetic background and nutritional features is improving the current understanding of the obesity physiopathogenesis and the usefulness of translating this precision information in the clinical setting for weight gain prediction, the design of personalized nutrition therapies as well as individual responsiveness estimation to dietary advice. The analysis of further relationships between the genotype, the epigenotype and other precision markers including the gut microbiota and the metabolome is warranted.

Pediococcus acidilactici CECT9879 (pA1c) Counteracts the Effect of a High-Glucose Exposure in C. elegans by Affecting the Insulin Signaling Pathway (IIS).

The increasing prevalence of metabolic syndrome-related diseases, including type-2 diabetes and obesity, makes it urgent to develop new alternative therapies, such as probiotics. In this study, we have used Caenorhabditis elegans under a high-glucose condition as a model to examine the potential probiotic activities of Pediococcusacidilactici CECT9879 (pA1c). The supplementation with pA1c reduced C. elegans fat accumulation in a nematode growth medium (NGM) and in a high-glucose (10 mM) NGM medium. Moreover, treatment with pA1c counteracted the effect of the high glucose by reducing reactive oxygen species by 20%, retarding the aging process and extending the nematode median survival (>2 days in comparison with untreated control worms). Gene expression analyses demonstrated that the probiotic metabolic syndrome-alleviating activities were mediated by modulation of the insulin/IGF-1 signaling pathway (IIS) through the reversion of the glucose-nuclear-localization of daf-16 and the overexpression of ins-6 and daf-16 mediators, increased expression of fatty acid (FA) peroxisomal ß-oxidation genes, and downregulation of FA biosynthesis key genes. Taken together, our data suggest that pA1c could be considered a potential probiotic strain for the prevention of the metabolic syndrome-related disturbances and highlight the use of C. elegans as an appropriate in vivo model for the study of the mechanisms underlying these diseases.

A predictive regression model of the obesity-related inflammatory status based on gut microbiota composition.

BACKGROUND AND AIM: Fecal microbiome disturbances are linked to different human diseases. In the case of obesity, gut microbiota seems to play a role in the development of low-grade inflammation. The purpose of the present study was to identify specific bacterial families and genera associated with an increased obesity-related inflammatory status, which would allow to build a regression model for the prediction of the inflammatory status of obese and overweight subjects based on fecal microorganisms. METHODS: A total of 361 volunteers from the Obekit trial (65 normal-weight, 110 overweight, and 186 obese) were classified according to four variables: waist/hip ratio (≥0.86 for women and ≥1.00 for men), leptin/adiponectin ratio (LAR, ≥3.0 for women and ≥1.4 for men), and plasma C-reactive protein (≥2 mg/L) and TNF levels (≥0.85 pg/mL). An inflammation score was designed to classify individuals in low (those subjects who did exceed the threshold value in 0 or 1 variable) or high inflammatory index (those subjects who did exceed the threshold value in 2 or more variables). Fecal 16 S rRNA sequencing was performed for all participants, and differential abundance analyses for family and genera were performed using the MicrobiomeAnalyst web-based platform. RESULTS: Methanobacteriaceae, Christensenellaceae, Coriobacteriaceae, Bifidobacteriaceae, Catabacteriaceae, and Dehalobacteriaceae families, and Methanobrevibacter, Eggerthella, Gemmiger, Anaerostipes, and Collinsella genera were significantly overrepresented in subjects with low inflammatory index. Conversely, Carnobacteriaceae, Veillonellaceae, Pasteurellaceae, Prevotellaceae and Enterobacteriaceae families, and Granulicatella, Veillonella, Haemophilus, Dialister Parabacteroides, Prevotella, Shigella, and Allisonella genera were more abundant in subjects with a high inflammatory index. A regression model adjusted by BMI, sex, and age and including the families Coriobacteriaceae and Prevotellaceae and the genus Veillonella was developed. CONCLUSION: A microbiota-based regression model was able to predict the obesity-related inflammatory status (area under the ROC curve = 0.8570 ± 0.0092 Harrell's optimism-correction) and could be useful in the precision management of inflammobesity.

Epigenetic signatures underlying inflammation: an interplay of nutrition, physical activity, metabolic diseases, and environmental factors for personalized nutrition.

AIM AND OBJECTIVE: Emerging translational evidence suggests that epigenetic alterations (DNA methylation, miRNA expression, and histone modifications) occur after external stimuli and may contribute to exacerbated inflammation and the risk of suffering several diseases including diabetes, cardiovascular diseases, cancer, and neurological disorders. This review summarizes the current knowledge about the harmful effects of high-fat/high-sugar diets, micronutrient deficiencies (folate, manganese, and carotenoids), obesity and associated complications, bacterial/viral infections, smoking, excessive alcohol consumption, sleep deprivation, chronic stress, air pollution, and chemical exposure on inflammation through epigenetic mechanisms. Additionally, the epigenetic phenomena underlying the anti-inflammatory potential of caloric restriction, n-3 PUFA, Mediterranean diet, vitamin D, zinc, polyphenols (i.e., resveratrol, gallic acid, epicatechin, luteolin, curcumin), and the role of systematic exercise are discussed. METHODS: Original and review articles encompassing epigenetics and inflammation were screened from major databases (including PubMed, Medline, Science Direct, Scopus, etc.) and analyzed for the writing of the review paper. CONCLUSION: Although caution should be exercised, research on epigenetic mechanisms is contributing to understand pathological processes involving inflammatory responses, the prediction of disease risk based on the epigenotype, as well as the putative design of therapeutic interventions targeting the epigenome.

Diet- and sex-related changes of gut microbiota composition and functional profiles after 4 months of weight loss intervention.

PURPOSE: Obesity has been related to intestinal dysbiosis and the modification of gut microbiota composition by dietary strategies becomes a promising strategy to help manage obesity. The aim of the current study was to evaluate the effect of two weight-loss diets on the composition and functional profile of gut microbiota. METHODS: 55 men and 124 women with BMI > 25 kg/m2 were randomly assigned to moderately high-protein (MHP) or low-fat (LF) diet. Differences in fecal bacteria abundance (based on 16 s rRNA sequencing) between before and after 4 months of calorie restriction was analyzed using EdgeR tool in MicrobiomeAnalyst platform. Bacterial functional profile was predicted using Tax4Fun and metagenomeSeq analysis. Significant KEGG Orthology (KO) terms were selected for the metabolomic study using chromatography. RESULTS: After the intervention, MHP-men showed a significant decrease in Negativicutes, Selenomonadales, Dielma and Dielma fastidiosa. LF-men showed a significant increase in Bacilli, Lactobacillales, Christensenellaceae, Peptococcaceae, and Streptococcaceae, Peptococcus, Streptococcus and Christensenella, Duncaniella dubosii_CP039396_93.49%, Roseburia sp_AB744234_98.96% and Alistipes inops_KJ572413_99.57%. MHP-women increased Pasteurellales, Phascolarctobacterium succinatutens, Ruthenibacterium lactatiformans_LR215981_99.55% and decreased in Phascolarctobacterium succinatutens_NR112902_99.56%. Finally, LF-women presented a significant decrease in Bacteroides clarus and Erysipelothrix inopinata_CP060715_84.4%. Surprisingly, no matching bacterial changes were found between these four groups. A total of 42 KO, 10 metabolic pathways and 107 related metabolites related were found implicated in these bacterial changes. Seven metabolites were confirmed in plasma. CONCLUSION: Weight-loss-related-changes in gut microbiome composition and the functional profile occur in a sex- and diet-related manner, showing that women and men could differentially benefit from the consumption of MHP and LF diets. TRIAL REGISTRATION: NCT02737267, 10th March 2016 retrospectively registered.

Differential response to a 6-month energy-restricted treatment depending on SH2B1 rs7359397 variant in NAFLD subjects: Fatty Liver in Obesity (FLiO) Study.

PURPOSE: Non-alcoholic fatty liver disease (NAFLD) is worldwide recognized as the most common cause of chronic liver disease. Current NAFLD clinical management relies on lifestyle change, nevertheless, the importance of the genetic make-up on liver damage and the possible interactions with diet are still poorly understood. The aim of the study was to evaluate the influence of the SH2B1 rs7359397 genetic variant on changes in body composition, metabolic status and liver health after 6-month energy-restricted treatment in overweight/obese subjects with NAFLD. In addition, gene-treatment interactions over the course of the intervention were examined. METHODS: The SH2B1 genetic variant was genotyped in 86 overweight/obese subjects with NAFLD from the FLiO study (Fatty Liver in Obesity study). Subjects were metabolically evaluated at baseline and at 6-months. Liver assessment included ultrasonography, Magnetic Resonance Imaging, elastography, a lipidomic test (OWL®-test) and specific blood liver biomarkers. Additionally, body composition, general biochemical markers and dietary intake were determined. RESULTS: Both genotypes significantly improved their body composition, general metabolic status and liver health after following an energy-restricted strategy. Liver imaging techniques showed a greater decrease in liver fat content (- 44.3%, p < 0.001) and in serum ferritin levels (p < 0.001) in the carriers of the T allele after the intervention. Moreover, lipidomic analysis, revealed a higher improvement in liver status when comparing risk vs. no-risk genotype (p = 0.006 vs. p = 0.926, respectively). Gene-treatment interactions showed an increase in fiber intake and omega-3 fatty acid in risk genotype (p interaction = 0.056 and p interaction = 0.053, respectively), while a significant increase in MedDiet score was observed in both genotype groups (p = 0.020). Moreover, no-risk genotype presented a relevant decrease in hepatic iron as well as in MUFA intake (p = 0.047 and p = 0.034, respectively). CONCLUSION: Subjects carrying the T allele of the rs7359397 polymorphism may benefit more in terms of hepatic health and liver status when prescribed an energy-restricted treatment, where a Mediterranean dietary pattern rich in fiber and other components such as omega-3 fatty acids might boost the benefits. TRIAL REGISTRATION: The Fatty Liver in Obesity was approved by the Research Ethics Committee of the University of Navarra and retrospectively registered (NCT03183193; www.clinicaltrials.gov ); June 2017.

Endothelial Nox5 Expression Modulates Glucose Uptake and Lipid Accumulation in Mice Fed a High-Fat Diet and 3T3-L1 Adipocytes Treated with Glucose and Palmitic Acid.

Obesity is a global health issue associated with insulin resistance and altered lipid homeostasis. It has been described that reactive oxygen species (ROS) derived from nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) activity are involved in the development of these pathologies. The present study describes the role of endothelial NOX5 expression over adipose tissue by using two experimental systems: NOX5 conditional knock-in mice fed with a high-fat diet and 3T3-L1 adipocytes cultured with conditioned media of NOX5-expressing endothelial cells previously treated with glucose and palmitic acid. Animals expressing NOX5 presented lower body weight gain and less mesenteric and epididymal adipose mass compared to control mice fed with the same diet. NOX5-expressing mice also showed significantly lower glycaemia and improved insulin-induced glucose uptake. In addition, Glut4 and Caveolin 1 (Cav1) expression were significantly increased in the adipose tissue of these animals. Likewise, 3T3-L1 adipocytes treated with conditioned media from NOX5-expressing endothelial cells, incubated with high glucose and palmitic acid, presented a reduction in lipid accumulation and an increase in glucose uptake. Moreover, a significant increase in the expression of Glut4 and Cav1 was also detected in these cells. Taken together, all these data support that, in response to a highly caloric diet, NOX5 endothelial activity may regulate glucose sensitivity and lipid homeostasis in the adipose tissue.

Microencapsulated Bifidobacterium bifidum and Lactobacillus gasseri in Combination with Quercetin Inhibit Colorectal Cancer Development in ApcMin/+ Mice.

Recent studies have suggested that flavonoids such as quercetin and probiotics such as Bifidobacterium bifidum (Bf) and Lactobacillus gasseri (Lg) could play a relevant role in inhibiting colon cancer cell growth. Our study investigated the role of dietary supplementation with microencapsulated probiotics (Bf and Lg) along with quercetin in the development of mouse colorectal cancer (CRC). Methods: Adenomatous polyposis coli/multiple intestinal neoplasia (ApcMin/+) mice were fed a standard diet or the same diet supplemented with microencapsulated probiotics (Bf and Lg strains, 107 CFU/100 g food) or both probiotics strains plus microencapsulated quercetin (15 mg/100 g food) for 73 days. Changes in body and organ weights, energy metabolism, intestinal microbiota, and colon tissue were determined. The expression of genes related to the Wnt pathway was also analyzed in colon samples. Results: Dietary supplementation with microencapsulated probiotics or microencapsulated probiotics plus quercetin reduced body weight loss and intestinal bleeding in ApcMin/+ mice. An improvement in energy expenditure was observed after 8 weeks but not after 10 weeks of treatment. A supplemented diet with microencapsulated Bf and Lg reduced the number of aberrant crypt foci (ACF) and adenomas by 45% and 60%, respectively, whereas the supplementation with Bf, Lg and quercetin decreased the number of ACF and adenomas by 57% and 80%, respectively. Microencapsulated Bf and Lg in combination with quercetin could exert inhibition of the canonical Wnt/ß-catenin signaling pathway in the colon of ApcMin/+ mice Conclusions: The administration of microencapsulated Bf and Lg, individually or in combination with quercetin, inhibits the CRC development in ApcMin/+ mice.

Circulating adiposity-related microRNAs as predictors of the response to a low-fat diet in subjects with obesity.

Recent studies have revealed the critical role of several microRNAs (miRNAs) in energy homeostasis and metabolic processes and suggest that circulating miRNAs can be used as early predictors of weight loss in the design of precision nutrition. Thus, the aim of this study was to investigate circulating adiposity-related miRNAs as biomarkers of the response to two specific weight loss dietary treatments. The expression of 86 miRNAs was investigated in plasma of 78 subjects with obesity randomized to two different diets [moderately high-protein diet (n = 38) and low-fat diet (n = 40)] and in 25 eutrophic controls (BMI ≤ 25 kg/m2 ). Bioinformatic analyses were performed to explore the target genes and biological pathways regulated by the dysregulated miRNAs. As results, 26 miRNAs were found differently expressed in eutrophic and volunteers with obesity. Moreover, 7 miRNAs (miR-130a-3p, miR-142-5p, miR-144-5p, miR-15a-5p, miR-22-3p, miR-221-3p and miR-29c-3p) were differentially expressed between responders and non-responders to a low-fat diet. Furthermore, after adjustment for basal glucose levels, 1-SD increase in miR-22-3p expression was associated with reduction in the risk of non-response to low-fat diet [OR = 0.181, 95% CI (0.084-0.947), P = .043]. Bioinformatic analyses evidenced that these 7 miRNAs regulate the expression of genes participating in important metabolic pathways. Conclusively, 7 circulating miRNAs related to adiposity could be used for predicting the response to a low-fat diet intervention prescribed to lose weight.

Comprehensive Analysis Reveals Novel Interactions between Circulating MicroRNAs and Gut Microbiota Composition in Human Obesity.

BACKGROUND: The determinants that mediate the interactions between microRNAs and the gut microbiome impacting on obesity are scarcely understood. Thus, the aim of this study was to investigate possible interactions between circulating microRNAs and gut microbiota composition in obesity. METHOD: The sample comprised 78 subjects with obesity (cases, body mass index (BMI): 30-40 kg/m2) and 25 eutrophic individuals (controls, BMI ≤ 25 kg/m2). The expression of 96 microRNAs was investigated in plasma of all individuals using miRCURY LNA miRNA Custom PCR Panels. Bacterial DNA sequencing was performed following the Illumina 16S protocol. The FDR correction was used for multiple comparison analyses. RESULTS: A total of 26 circulating microRNAs and 12 bacterial species were found differentially expressed between cases and controls. Interestingly, an interaction among three miRNAs (miR-130b-3p, miR-185-5p and miR-21-5p) with Bacteroides eggerthi and BMI levels was evidenced (r2 = 0.148, p = 0.004). Moreover, these microRNAs regulate genes that participate in metabolism-related pathways, including fatty acid degradation, insulin signaling and glycerolipid metabolism. CONCLUSIONS: This study characterized an interaction between the abundance of 4 bacterial species and 14 circulating microRNAs in relation to obesity. Moreover, the current study also suggests that miRNAs may serve as a communication mechanism between the gut microbiome and human hosts.

Oral Phenelzine Treatment Mitigates Metabolic Disturbances in Mice Fed a High-Fat Diet.

Novel mechanisms and health benefits have been recently suggested for the antidepressant drug phenelzine (PHE), known as a nonselective monoamine oxidase inhibitor. They include an antilipogenic action that could have an impact on excessive fat accumulation and obesity-related metabolic alterations. We evaluated the metabolic effects of an oral PHE treatment on mice fed a high-fat diet (HFD). Eleven-week-old male C57BL/6 mice were fed a HFD and either a 0.028% PHE solution (HFD + PHE) or water to drink for 11 weeks. PHE attenuated the increase in body weight and adiposity without affecting food consumption. Energy efficiency was lower in HFD + PHE mice. Lipid content was reduced in subcutaneous fat pads, liver, and skeletal muscle. In white adipose tissue (WAT), PHE reduced sterol regulatory element-binding protein-1c and phosphoenolpyruvate carboxykinase mRNA levels, inhibited amine-induced lipogenesis, and did not increase lipolysis. Moreover, HFD + PHE mice presented diminished levels of hydrogen peroxide release in subcutaneous WAT and reduced expression of leukocyte transmigration markers and proinflammatory cytokines in visceral WAT and liver. PHE reduced the circulating levels of glycerol, triacylglycerols, high-density lipoprotein cholesterol, and insulin. Insulin resistance was reduced, without affecting glucose levels and glucose tolerance. In contrast, PHE increased rectal temperature and slightly increased energy expenditure. The mitigation of HFD-induced metabolic disturbances points toward a promising role for PHE in obesity treatment and encourages further research on its mechanisms of action. SIGNIFICANCE STATEMENT: Phenelzine reduces body fat, markers of oxidative stress, inflammation, and insulin resistance in high-fat diet mice. Semicarbazide-sensitive amine oxidase, monoamine oxidase, phosphoenolpyruvate carboxykinase, and sterol regulatory element-binding protein-1c are involved in the metabolic effects of phenelzine. Phenelzine could be potentially used for the treatment of obesity-related complications.

MicroRNAs and other non-coding RNAs in adipose tissue and obesity: emerging roles as biomarkers and therapeutic targets.

Obesity is a metabolic condition usually accompanied by insulin resistance (IR), type 2 diabetes (T2D), and dyslipidaemia, which is characterised by excessive fat accumulation and related to white adipose tissue (WAT) dysfunction. Enlargement of WAT is associated with a transcriptional alteration of coding and non-coding RNAs (ncRNAs). For many years, big efforts have focused on understanding protein-coding RNAs and their involvement in the regulation of adipocyte physiology and subsequent role in obesity. However, diverse findings have suggested that a dysfunctional adipocyte phenotype in obesity might be also dependent on specific alterations in the expression pattern of ncRNAs, such as miRNAs. The aim of this review is to update current knowledge on the physiological roles of miRNAs and other ncRNAs in adipose tissue function and their potential impact on obesity. Therefore, we examined their regulatory role on specific WAT features: adipogenesis, adipokine secretion, inflammation, glucose metabolism, lipolysis, lipogenesis, hypoxia and WAT browning. MiRNAs can be released to body fluids and can be transported (free or inside microvesicles) to other organs, where they might trigger metabolic effects in distant tissues, thus opening new possibilities to a potential use of miRNAs as biomarkers for diagnosis, prognosis, and personalisation of obesity treatment. Understanding the role of miRNAs also opens the possibility of using these molecules on individualised dietary strategies for precision weight management. MiRNAs should be envisaged as a future therapeutic approach given that miRNA levels could be modulated by synthetic molecules (f.i. miRNA mimics and inhibitors) and/or specific nutrients or bioactive compounds.

Association of Methylation Signatures at Hepatocellular Carcinoma Pathway Genes with Adiposity and Insulin Resistance Phenotypes.

Obesity and type 2 diabetes mellitus are independent risk factors for the onset and progression of hepatocellular carcinoma (HCC). This study aimed to analyze the association of DNA methylation signatures at HCC pathway genes with obesity and related metabolic disturbances. A population of 474 adults within the Methyl Epigenome Network Association (MENA) project was included. DNA methylation levels were measured in white blood cells by microarray. The identification and discrimination of HCC pathway genes were performed using KEGG and PathDIP databases. Anthropometry measurements, the blood metabolic profile, and clinical data were analyzed. The methylation patterns of 20 CpG sites at HCC pathway genes strongly correlated with BMI (FDR <0.0001). These genes encompassed GADD45A, MTOR, FRAT2, E2F3, WNT7B, FRAT1, LRP5, DPF3, GSTA2, APC, MYC, WNT10B, ARID1B, AKT1, GSTA1, WNT5A, CDK4, GAB1, TCF7, which statistically contributed to the regulation of the HCC pathway (P = 2.10e-07). The main biological process where these genes were implicated included uncontrolled cell proliferation, DNA damage, increased survival, and altered oncogenic expression. Interestingly, 9 out of 20 BMI-associated CpGs also correlated with waist circumference and HOMA-IR index. In conclusion, pathway analysis revealed potential associations of DNA methylation signatures at HCC pathway genes with adiposity and insulin resistance phenotypes.

An integrated transcriptomic and epigenomic analysis identifies CD44 gene as a potential biomarker for weight loss within an energy-restricted program.

PURPOSE: The interindividual variable response to weight-loss treatments requires the search for new predictive biomarkers for improving the success of weight-loss programs. The aim of this study is to identify novel genes that distinguish individual responses to a weight-loss dietary treatment by using the integrative analysis of mRNA expression and DNA methylation arrays. METHODS: Subjects from Metabolic Syndrome Reduction in Navarra (RESMENA) project were classified as low (LR) or high (HR) responders depending on their weight loss. Transcriptomic (n = 24) and epigenomic (n = 47) patterns were determined by array-based genome-wide technologies in human white blood cells at the baseline of the treatment period. CD44 expression was validated by qRT-PCR and methylation degree of CpGs of the gene was validated by MassARRAY® EpiTYPER™ in a subsample of 47 subjects. CD44 protein levels were measured by ELISA in human plasma. RESULTS: Different expression and DNA methylation profiles were identified in LR in comparison to HR. The integrative analysis of both array data identified four genes: CD44, ITPR1, MTSS1 and FBXW5 that were differently methylated and expressed between groups. CD44 showed higher expression and lower DNA methylation levels in LR than in HR. Although differences in CD44 protein levels between LR and HR were not statistically significant, a positive association was observed between CD44 mRNA expression and protein levels. CONCLUSIONS: In summary, the combination of a genome-wide methylation and expression array dataset can be a useful strategy to identify novel genes that might be considered as predictors of the dietary response. CD44 gene transcription and methylation may be a possible candidate biomarker for weight-loss prediction.

miRNAs and Novel Food Compounds Related to the Browning Process.

Obesity prevalence is rapidly increasing worldwide. With the discovery of brown adipose tissue (BAT) in adult humans, BAT activation has emerged as a potential strategy for increasing energy expenditure. Recently, the presence of a third type of fat, referred to as beige or brite (brown in white), has been recognized to be present in certain kinds of white adipose tissue (WAT) depots. It has been suggested that WAT can undergo the process of browning in response to stimuli that induce and enhance the expression of thermogenesis: a metabolic feature typically associated with BAT. MicroRNAs (miRNAs) are small transcriptional regulators that control gene expression in a variety of tissues, including WAT and BAT. Likewise, it was shown that several food compounds could influence miRNAs associated with browning, thus, potentially contributing to the management of excessive adipose tissue accumulation (obesity) through specific nutritional and dietetic approaches. Therefore, this has created significant excitement towards the development of a promising dietary strategy to promote browning/beiging in WAT to potentially contribute to combat the growing epidemic of obesity. For this reason, we summarize the current knowledge about miRNAs and food compounds that could be applied in promoting adipose browning, as well as the cellular mechanisms involved.

Insulin Sensitivity Is Associated with Lipoprotein Lipase (LPL) and Catenin Delta 2 (CTNND2) DNA Methylation in Peripheral White Blood Cells in Non-Diabetic Young Women.

Hyperglycaemia and type 2 diabetes (T2D) are associated with impaired insulin secretion and/or insulin action. Since few studies have addressed the relation between DNA methylation patterns with elaborated surrogates of insulin secretion/sensitivity based on the intravenous glucose tolerance test (IVGTT), the aim of this study was to evaluate the association between DNA methylation and an insulin sensitivity index based on IVGTT (calculated insulin sensitivity index (CSi)) in peripheral white blood cells from 57 non-diabetic female volunteers. The CSi and acute insulin response (AIR) indexes, as well as the disposition index (DI = CSi × AIR), were estimated from abbreviated IVGTT in 49 apparently healthy Chilean women. Methylation levels were assessed using the Illumina Infinium Human Methylation 450k BeadChip. After a statistical probe filtering, the two top CpGs whose methylation was associated with CSi were cg04615668 and cg07263235, located in the catenin delta 2 (CTNND2) and lipoprotein lipase (LPL) genes, respectively. Both CpGs conjointly predicted insulin sensitivity status with an area under the curve of 0.90. Additionally, cg04615668 correlated with homeostasis model assessment insulin-sensitivity (HOMA-S) and AIR, whereas cg07263235 was associated with plasma creatinine and DI. These results add further insights into the epigenetic regulation of insulin sensitivity and associated complications, pointing the CTNND2 and LPL genes as potential underlying epigenetic biomarkers for future risk of insulin-related diseases.