Maria Luisa Mansego

Expression of inflammation-related miRNAs in white blood cells from subjects with metabolic syndrome after 8 wk of following a Mediterranean diet-based weight loss program

OBJECTIVES The aim of this study was to evaluate the influence of a dietary strategy for weight loss (the RESMENA [reduction of metabolic syndrome in Navarra, Spain] diet) on the expression of inflammation-related microRNAS (miRNAs) and genes in white blood cells (WBC) from individuals with metabolic syndrome (MetS). METHODS The clinical, anthropometric, and biochemical characteristics of 40 individuals with MetS (20 men and 20 women; age: 48.84 ± 10.02 y; body mass index: 35.41 ± 4.42 kg/m(2)) were evaluated before and after an 8-wk hypocaloric diet based on the Mediterranean dietary pattern. Nutrient intake was assessed with a food frequency questionnaire and 48-h weighed food records. Total RNA was isolated from WBC and the expression of some inflammation-related miRNAs and mRNAs (IL-6, TNF-α, ICAM-1, IL-18, SERPINE1, VCAM-1, GAPDH) was assessed by quantitative polymerase chain reaction. RESULTS The RESMENA nutritional intervention improved most anthropometric and biochemical features. The expression of miR-155-3p was decreased in WBC, whereas Let-7b was strongly upregulated as a consequence of the dietary treatment. However, they were not correlated with the expression of the proinflammatory genes in the same cells. The changes in the expression of let-7b, miR-125b, miR-130a, miR-132-3p, and miR-422b were significantly associated with changes in diet quality when assessed by the Healthy Eating Index. Moreover, low consumption of lipids and saturated fat (g/d) were associated with higher expression of let-7b after the nutritional intervention. CONCLUSIONS The Mediterranean-based nutritional intervention was able to induce changes in the expression of let-7b and miR-155-3p in WBC from patients with MetS after 8 wk. Moreover, the quality of the diet has an important effect on the miRNAs expression changes. These results should be highlighted because these miRNAs have been associated with inflammatory gene regulation and important human diseases.

SERPINE1 , PAI-1 protein coding gene, methylation levels and epigenetic relationships with adiposity changes in obese subjects with metabolic syndrome features under dietary restriction

Plasminogen activator inhibitor 1 (PAI-1) has been associated with metabolic disorders, through different mechanisms, which could involve changes in DNA methylation. This work aimed to assess the potential relationships of the cytosine methylation levels within SERPINE1 gene transcriptional regulatory region, which codes for PAI-1, in peripheral white blood cells with anthropometrical, metabolic and inflammatory features. Forty-six obese subjects with metabolic syndrome features followed Control or Metabolic Syndrome Reduction in Navarra (RESMENA) energy-restricted (−30%E) diets for 8 weeks. SERPINE1 transcriptional regulatory region methylation at baseline was analyzed by a microarray technical. Both dietary strategies reduced anthropometric and biochemical parameters. The Control group significantly reduced plasma PAI-1 concentrations but not the RESMENA group. Participants from both nutritional interventions with higher SERPINE1 methylation levels at baseline showed significantly major reductions in body weight, total fat mass, android fat mass, total cholesterol and triglycerides, as compared with those with lower initial SERPINE1 methylation levels. In conclusion, the DNA methylation levels of SERPINE1 transcriptional regulatory region were associated with some metabolic and anthropometric changes in obese subjects with metabolic syndrome under energy restriction, suggesting a complex epigenetic network in the regulation of this recognized pro-inflammatory marker. (www.clinicaltrials.gov; NCT01087086)

Techniques of DNA Methylation Analysis with Nutritional Applications

Epigenetic mechanisms are likely to play an important role in the regulation of metabolism and body weight through gene-nutrient interactions. This review focuses on methods for analyzing one of the most important epigenetic mechanisms, DNA methylation, from single nucleotide to global measurement depending on the study goal and scope. In addition, this study highlights the major principles and methods for DNA methylation analysis with emphasis on nutritional applications. Recent developments concerning epigenetic technologies are showing promising results of DNA methylation levels at a single-base resolution and provide the ability to differentiate between 5-methylcytosine and other nucleotide modifications such as 5-hydroxymethylcytosine. A large number of methods can be used for the analysis of DNA methylation such as pyrosequencing™, primer extension or real-time PCR methods, and genome-wide DNA methylation profile from microarray or sequencing-based methods. Researchers should conduct a preliminary analysis focused on the type of validation and information provided by each technique in order to select the best method fitting for their nutritional research interests.

Oxidative stress in susceptibility to breast cancer: study in Spanish population

BackgroundAlterations in the redox balance are involved in the origin, promotion and progression of cancer. Inter-individual differences in the oxidative stress regulation can explain a part of the variability in cancer susceptibility.The aim of this study was to evaluate if polymorphisms in genes codifying for the different systems involved in oxidative stress levels can have a role in susceptibility to breast cancer.MethodsWe have analyzed 76 single base polymorphisms located in 27 genes involved in oxidative stress regulation by SNPlex technology. First, we have tested all the selected SNPs in 493 breast cancer patients and 683 controls and we have replicated the significant results in a second independent set of samples (430 patients and 803 controls). Gene-gene interactions were performed by the multifactor dimensionality reduction approach.ResultsSix polymorphisms rs1052133 (OGG1), rs406113 and rs974334 (GPX6), rs2284659 (SOD3), rs4135225 (TXN) and rs207454 (XDH) were significant in the global analysis. The gene-gene interactions demonstrated a significant four-variant interaction among rs406113 (GPX6), rs974334 (GPX6), rs105213 (OGG1) and rs2284659 (SOD3) (p-value = 0.0008) with high-risk genotype combination showing increased risk for breast cancer (OR = 1.75 [95% CI; 1.26-2.44]).ConclusionsThe results of this study indicate that different genotypes in genes of the oxidant/antioxidant pathway could affect the susceptibility to breast cancer. Furthermore, our study highlighted the importance of the analysis of the epistatic interactions to define with more accuracy the influence of genetic variants in susceptibility to breast cancer.

Differential DNA Methylation in Relation to Age and Health Risks of Obesity

The aim of this study was to evaluate whether genome-wide levels of DNA methylation are associated with age and the health risks of obesity (HRO); defined according to BMI categories as “Low HRO” (overweight and class 1 obesity) versus “High HRO” (class 2 and class 3 obesity). Anthropometric measurements were assessed in a subsample of 48 volunteers from the Metabolic Syndrome Reduction in Navarra (RESMENA) study and 24 women from another independent study, Effects of Lipoic Acid and Eicosapentaenoic Acid in Human Obesity (OBEPALIP study). In the pooled population; the methylation levels of 55 CpG sites were significantly associated with age after Benjamini-Hochberg correction. In addition, DNA methylation of three CpG sites located in ELOVL2; HOXC4 and PI4KB were further negatively associated with their mRNA levels. Although no differentially methylated CpG sites were identified in relation to HRO after multiple testing correction; several nominally significant CpG sites were identified in genes related to insulin signaling; energy and lipid metabolism. Moreover, statistically significant associations between BMI or mRNA levels and two HRO-related CpG sites located in GPR133 and ITGB5 are reported. As a conclusion, these findings from two Spanish cohorts add knowledge about the important role of DNA methylation in the age-related regulation of gene expression. In addition; a relevant influence of age on DNA methylation in white blood cells was found, as well as, on a trend level, novel associations between DNA methylation and obesity.

LINE-1 methylation is positively associated with healthier lifestyle but inversely related to body fat mass in healthy young individuals

Abstract With the goal of investigating if epigenetic biomarkers from white blood cells (WBC) are associated with dietary, anthropometric, metabolic, inflammatory and oxidative stress parameters in young and apparently healthy individuals. We evaluated 156 individuals (91 women, 65 men; age: 23.1±3.5 years; body mass index: 22.0±2.9 kg/m2) for anthropometric, biochemical and clinical markers, including some components of the antioxidant defense system and inflammatory response. DNA methylation of LINE-1, TNF-α and IL-6 and the expression of some genes related to the inflammatory process were analyzed in WBC. Adiposity was lower among individuals with higher LINE-1 methylation. On the contrary, body fat-free mass was higher among those with higher LINE-1 methylation. Individuals with higher LINE-1 methylation had higher daily intakes of calories, iron and riboflavin. However, those individuals who presented lower percentages of LINE-1 methylation reported higher intakes of copper, niacin and thiamin. Interestingly, the group with higher LINE-1 methylation had a lower percentage of current smokers and more individuals practicing sports. On the other hand, TNF-α methylation percentage was negatively associated with waist girth, waist-to-hip ratio and waist-to-stature ratio. Plasma TNF-α levels were lower in those individuals with higher TNF-α methylation. This study suggests that higher levels of LINE-1 and TNF-α methylation are associated with better indicators of adiposity status in healthy young individuals. In addition, energy and micronutrient intake, as well as a healthy lifestyle, may have a role in the regulation of DNA methylation in WBC and the subsequent metabolic changes may affect epigenetic biomarkers.

DNA Hypermethylation of the Serotonin Receptor Type-2A Gene Is Associated with a Worse Response to a Weight Loss Intervention in Subjects with Metabolic Syndrome

Understanding the regulation of gene activities depending on DNA methylation has been the subject of much recent study. However, although polymorphisms of the HTR2A gene have been associated with both obesity and psychiatric disorders, the role of HTR2A gene methylation in these illnesses remains uncertain. The aim of this study was to evaluate the association of HTR2A gene promoter methylation levels in white blood cells (WBC) with obesity traits and depressive symptoms in individuals with metabolic syndrome (MetS) enrolled in a behavioural weight loss programme. Analyses were based on 41 volunteers (mean age 49 ± 1 year) recruited within the RESMENA study. Depressive symptoms (as determined using the Beck Depression Inventory), anthropometric and biochemical measurements were analysed at the beginning and after six months of weight loss treatment. At baseline, DNA from WBC was isolated and cytosine methylation in the HTR2A gene promoter was quantified by a microarray approach. In the whole-study sample, a positive association of HTR2A gene methylation with waist circumference and insulin levels was detected at baseline. Obesity measures significantly improved after six months of dietary treatment, where a lower mean HTR2A gene methylation at baseline was associated with major reductions in body weight, BMI and fat mass after the treatment. Moreover, mean HTR2A gene methylation at baseline significantly predicted the decrease in depressive symptoms after the weight loss treatment. In conclusion, this study provides newer evidence that hypermethylation of the HTR2A gene in WBC at baseline is significantly associated with a worse response to a weight-loss intervention and with a lower decrease in depressive symptoms after the dietary treatment in subjects with MetS.

SH2B1 CpG-SNP is associated with body weight reduction in obese subjects following a dietary restriction program.

The objective of this study was to examine whether 7 SNPs previously associated with obesity-related traits that add or remove potential sites of DNA methylation are accompanied by differential DNA methylation and subsequently affect adiposity variables or body weight reduction in WBC from obese subjects under an energy-restricted program. Material and Methods: Anthropometric measurements were assessed in 47 volunteers recruited within the RESMENA study (Spain). At baseline, DNA from white blood cells was isolated and 7 obesity-related trait CpG-SNPs were genotyped by TaqMan-PCR. Then, methylation levels of CpG-SNP sites were quantified by MassArray® EpiTyper™ or MS-HRM approaches. Results: Differential DNA methylation levels were observed by genotypes in all of the CpG-SNPs analyzed. The FTO and BDNF methylation levels were further correlated with baseline body weight and, BDNF mRNA levels and body weight change, respectively. Moreover, the rs7359397 (SH2B1) was associated with the body weight, body mass index, and truncal fat mass reduction. Conclusions: Our results reveal the interaction of epigenetic and genetic variations in CpG-SNPs, especially in BDNF and SH2B1 genes, and how allele-specific methylation may contribute to elucidate the possible molecular mechanisms as these SNPs are affecting the decrease of mRNA levels and contributing to a lower body weight reduction.

Arylesterase activity is associated with antioxidant intake and paraoxonase-1 (PON1) gene methylation in metabolic syndrome patients following an energy restricted diet

The arylesterase (ARE) activity linked to the paraoxonase-1 (PON1) gene is known to protect lipoproteins from oxidation and provide defense against metabolic syndrome (MetS) and cardiovascular diseases. The epigenetic regulation of enzymatic activities is gaining importance nowadays. This research aimed to assess the potential relationships between the ARE activity with the methylation levels of the PON1 gene transcriptional regulatory region, anthropometrics, biochemical markers and antioxidant dietary components. Forty-seven subjects (47 ± 10 y.o; BMI 36.2 ± 3.8 kg/m2; 46.8 % female) with MetS features, who followed a six-month energy-restricted dietary weight-loss intervention, were included in this study (www.clinicaltrials.gov; NCT01087086). Anthropometric, biochemical, enzymatic and dietary data were assessed using validated procedures. PON1 transcriptional regulatory region methylation was analyzed by a microarray technical approach. Volunteers reduced ARE activity in parallel with body weight (p = 0.005), BMI (p = 0.006), total fat mass (p = 0.020), diastolic blood pressure (p = 0.018), mean blood pressure (p = 0.022) and triglycerides (p = 0.014). Methylation levels of some CpG sites of the PON1 gene correlated negatively with ARE activity (p < 0.05). Interestingly, dietary vitamin C (p = 0.001), tocopherols (p = 0.009) and lycopene (p = 0.038) were positively associated with ARE activity and showed an inverse correlation (p = 0.004, p = 0.029 and p = 0.021, respectively) with the methylation of some selected CpG sites of the PON1 gene. In conclusion, ARE activity decreased in parallel with MetS-related markers associated to the energy restriction, while dietary antioxidants might enhance the ARE activity by lowering the PON1 gene methylation in patients with MetS features.

LINE-1 methylation levels, a biomarker of weight loss in obese subjects, are influenced by dietary antioxidant capacity

Objectives: Epigenetic markers, and in particular DNA methylation, have come to the fore as new tools in the personalization of the treatment of obesity and its comorbidities. The objectives of the current investigation were to identify epigenetic biomarkers that might be predictive of response to a weight-loss intervention, and to better understand the influence of certain nutrients (particularly antioxidants) on the epigenome. Methods: Global DNA (LINE-1) methylation levels were assessed in peripheral blood mononuclear cells (PBMCs) from 96 obese volunteers of the Metabolic Syndrome Reduction in Navarra study, using a methylation-sensitive high resolution melting approach after bisulfite modification. Results: Baseline LINE-1 DNA methylation levels were significantly higher (5.41%) in high responders (>8% of weight loss) as compared to low responders (<8%) to the energy-restricted treatment. Indeed, a LINE-1 methylation higher than 84.15% may be predictive of a high response to the hypocaloric diet. Statistically significant correlations were found between LINE-1 baseline DNA methylation levels and the response to the treatment involving total fat mass and body weight. Furthermore, LINE-1 baseline methylation levels positively correlated with baseline dietary total antioxidant capacity (TAC). Discussion: LINE-1 methylation levels in PBMCs might be used to predict response to a dietary weight-loss intervention, and seem to be related to the dietary TAC. Trial Registration: www.clinicaltrials.gov: NCT01087086.