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

Plasma Extracellular MicroRNAs Associated With Cardiovascular Disease Risk Factors in Middle-Aged and Older Adults

BACKGROUND

Extracellular microRNAs (miRNAs) are a class of noncoding RNAs that remain stable in the extracellular milieu, where they contribute to various physiological and pathological processes by facilitating intercellular signaling. Previous studies have reported associations between miRNAs and cardiovascular diseases (CVDs); however, the plasma miRNA signatures of CVD and its risk factors have not been fully elucidated at the population level.

METHODS AND RESULTS

Plasma miRNA levels were measured in 4440 FHS (Framingham Heart Study) participants. Linear regression analyses were conducted to test the cross-sectional associations of each miRNA with 8 CVD risk factors. Prospective analyses of the associations of miRNAs with new-onset obesity, hypertension, type 2 diabetes, CVD, and all-cause mortality were conducted using proportional hazards regression. Replication was carried out in 1999 RS (Rotterdam Study) participants. Pathway enrichment analyses were conducted and target genes were predicted for miRNAs associated with ≥5 risk factors in the FHS. In the FHS, 6 miRNAs (miR-193b-3p, miR-122-5p, miR-365a-3p, miR-194-5p, miR-192-5p, and miR-193a-5p) were associated with ≥5 risk factors. This miRNA signature was enriched for pathways associated with CVD and several genes annotated to these pathways were predicted targets of the identified miRNAs. Furthermore, miR-193b-3p, miR-194-5p, and miR-193a-5p were each associated with ≥2 risk factors in the RS. Prospective analysis revealed 8 miRNAs associated with all-cause mortality in the FHS.

CONCLUSIONS

These findings highlight associations between miRNAs and CVD risk factors that may provide valuable insights into the underlying pathogenesis of CVD.

Higher Expression of miR-15b-5p with Inclusion of Fresh, Lean Beef as Part of a Healthy Dietary Pattern Is Inversely Associated with Markers of Cardiometabolic Disease Risk

BACKGROUND

Considerable controversy exists surrounding the consumption of red meat and its impacts on cardiometabolic health and if it may further impact risk factors at the molecular level.

OBJECTIVE

The purpose of this study was to examine the acute effects of dietary patterns, varying in red meat quantity, on the expression of circulating microRNAs (miRNAs), which are emerging biomarkers of metabolic dysfunction and chronic disease severity.

METHODS

Secondary analyses were performed on plasma samples collected within a randomized, crossover design study in 16 women with overweight (mean ± standard deviation, age = 33 ± 9.89 y; body mass index = 27.9 ± 1.66 kg/m2). Participants were provided with eucaloric, isonitrogenous diets (15% of daily intake as protein) containing either 2 servings of fresh, lean beef/day (BEEF) or 0 servings of fresh, lean beef/day (PLANT) for 7 d/pattern. Fasting blood samples were collected at the end of each dietary pattern for the assessment of 12 circulating metabolic miRNA expression levels (determined a priori by quantitative reverse transcriptase-polymerase chain reaction), plasma glucose, insulin, interleukin-6, tumor necrosis factor-α, C-reactive protein (CRP), adiponectin, glucagon-like peptide-1, and branched-chain amino acids.

RESULTS

Of the 12 miRNAs, miR-15b-5p expression was higher following BEEF versus PLANT (P = 0.024). Increased miR-15b-5p expression correlated with decreased fasting CRP (r = -0.494; P = 0.086) and insulin concentrations (r = -0.670; P = 0.017). miR-15b-5p was inversely correlated with insulin resistance (r = -0.642; P = 0.024) and β cell function (r = -0.646; P = 0.023) and positively correlated with markers of insulin sensitivity (r = 0.520; P = 0.083). However, the correlations were only observed following BEEF, not PLANT.

CONCLUSIONS

These data indicate that the short-term intake of fresh, lean beef as part of a healthy dietary pattern impacts potential biomarkers of cardiometabolic health that are associated with cardiometabolic risk factors in women with overweight. This study was registered at clinicaltrials.gov as NCT02614729.

Childhood obesity, metabolic syndrome, and oxidative stress: microRNAs go on stage

The incidence of childhood obesity and metabolic syndrome has grown notably in the last years, becoming major public health burdens in developed countries. Nowadays, oxidative stress is well-recognized to be closely associated with the onset and progression of several obesity-related complications within the framework of a complex crosstalk involving other intertwined pathogenic events, such as inflammation, insulin disturbances, and dyslipidemia. Thus, understanding the molecular basis behind these oxidative dysregulations could provide new approaches for the diagnosis, prevention, and treatment of childhood obesity and associated disorders. In this respect, the transcriptomic characterization of miRNAs bares great potential because of their involvement in post-transcriptional modulation of genetic expression. Herein, we provide a comprehensive literature revision gathering state-of-the-art research into the association between childhood obesity, metabolic syndrome, and miRNAs. We put special emphasis on the potential role of miRNAs in modulating obesity-related pathogenic events, with particular focus on oxidative stress.

Identification of key genes related to intramuscular fat deposition in Beijing-You chicken by mRNA and miRNA transcriptome analysis

Intramuscular fat (IMF) is an important factor affecting chicken quality. However, the age-related mechanism of IMF deposition has not yet been elucidated. In this study, the IMF, phospholipids (PL), triglycerides (TG), and fatty acid (FA) content in the breast muscle of Beijing-You chicken (BJY) at 1, 56, 98, and 120 d of age was measured, and mRNA and miRNA sequencing was integrated to explore the regulatory genes of IMF deposition. The results showed that the IMF content of BJY at 1 d of age was significantly higher than that at later stage of birth (P < 0.05). The transcriptome sequencing results showed that 7, 225 differentially expressed genes (DEGs) and 243 differentially expressed miRNAs (DE-miRNAs) were identified. The cluster analysis showed that the expression of DEGs and DE-miRNAs at 1 d of age was significantly different from that at later stages of birth. Furthermore, a potential mRNA-miRNA regulatory network related to IMF deposition was established by weighted gene co-expression network analysis (WGCNA); gga-miR-29c-3p-PIK3R1, gga-miR-6701-3p-PTEN, gga-miR-363-3p-PTEN, gga-miR-1563-WWP1, gga-miR-449c/d-5p-TRAF6, and gga-miR-6701-3p-BMPR1B were identified as key mRNA-miRNA pairs for the regulation of IMF deposition. These results will help elucidate the mechanism of IMF formation mediated by miRNAs in chickens, and provide a theoretical foundation for the genetic improvement of broiler meat quality.

The Relationship between Depressive Symptoms, Quality of Life and miRNAs 8 Years after Bariatric Surgery

(1) Background: There are conflicting results on whether weight loss after bariatric surgery (BS) might be associated with quality of life (QoL)/depressive symptomatology. We aim to determine whether BS outcomes are associated with QoL/depressive symptomatology in studied patients at the 8-year follow-up after BS, as well as their relationship with different serum proteins and miRNAs. (2) Methods: A total of 53 patients with class III obesity who underwent BS, and then classified into "good responders" and "non-responders" depending on the percentage of excess weight lost (%EWL) 8 years after BS (%EWL ≥ 50% and %EWL < 50%, respectively), were included. Basal serum miRNAs and different proteins were analysed, and patients completed tests to evaluate QoL/depressive symptomatology at 8 years after BS. (3) Results: The good responders group showed higher scores on SF-36 scales of physical functioning, role functioning-physical, role functioning-emotional, body pain and global general health compared with the non-responders. The expression of hsa-miR-101-3p, hsa-miR-15a-5p, hsa-miR-29c-3p, hsa-miR-144-3p and hsa-miR-19b-3p were lower in non-responders. Hsa-miR-19b-3p was the variable associated with the response to BS in a logistic regression model. (4) Conclusions: The mental health of patients after BS is limited by the success of the intervention. In addition, the expression of basal serum miRNAs related to depression/anxiety could predict the success of BS.

Tissue and Circulating MicroRNAs 378 and 142 as Biomarkers of Obesity and Its Treatment Response

Promising approaches to the treatment of obesity include increasing energy expenditure and slowing down fibrogenesis of adipose tissue. The neurotransmitter reuptake inhibitor sibutramine affects appetite and activates lipolysis in a catecholaminergic way. MicroRNAs (miRs) are considered as biomarkers of molecular genetic mechanisms underlying various processes. The profile of a number of miRs is altered in obesity, both in the circulation and in adipose tissue. The aim of this study was to assess the expression levels of miRs (hsa-miR-378a-3p, hsa-miR-142-3p) by real-time polymerase chain reaction in subcutaneous adipose tissue (SAT) and in plasma in patients with different degrees and duration of obesity and during sibutramine therapy. This study included 51 obese patients and 10 healthy subjects with normal weight who formed a control group. The study found that, before treatment, obese patients had no significant difference in the expression level of miR-378 in SAT and plasma compared to the control group, while the expression of miR-142 was significantly decreased in SAT and increased in plasma. A significant elevation in miR-378 expression level was noted in patients with first-degree obesity and duration of less than 10 years, and the decline in miR-142 increased with the duration of obesity. These data indicate a maximal increase in the expression of the adipogenesis inducer miR-378 in the early stages of obesity, a progressive decrease in the expression of the fibrogenesis inhibitor miR-142 in SAT with growth of duration of obesity and the likely presence of antifibrogenic effects of sibutramine realized through miR-142 activation.

Environmental and Lifestyle Cancer Risk Factors: Shaping Extracellular Vesicle OncomiRs and Paving the Path to Cancer Development

Intercellular communication has been transformed by the discovery of extracellular vesicles (EVs) and their cargo, including microRNAs (miRNAs), which play crucial roles in intercellular signaling. These EVs were previously disregarded as cellular debris but are now recognized as vital mediators of biological information transfer between cells. Furthermore, they respond not only to internal stimuli but also to environmental and lifestyle factors. Identifying EV-borne oncomiRs, a subset of miRNAs implicated in cancer development, could revolutionize our understanding of how environmental and lifestyle exposures contribute to oncogenesis. To investigate this, we studied the plasma levels of EV-borne oncomiRs in a population of 673 women and 238 men with a body mass index > 25 kg/m2 (SPHERE population). The top fifty oncomiRs associated with the three most common cancers in women (breast, colorectal, and lung carcinomas) and men (lung, prostate, and colorectal carcinomas) were selected from the OncomiR database. Only oncomiRs expressed in more than 20% of the population were considered for statistical analysis. Using a Multivariate Adaptive Regression Splines (MARS) model, we explored the interactions between environmental/lifestyle exposures and EV oncomiRs to develop optimized predictor combinations for each EV oncomiR. This innovative approach allowed us to better understand miRNA regulation in response to multiple environmental and lifestyle influences. By uncovering non-linear relationships among variables, we gained valuable insights into the complexity of miRNA regulatory networks. Ultimately, this research paves the way for comprehensive exposome studies in the future.

MicroRNAs: a crossroad that connects obesity to immunity and aging

Obesity is characterized by an elevated amount of fat and energy storage in the adipose tissue (AT) and is believed to be the root cause of many metabolic diseases (MDs). Obesity is associated with low-grade chronic inflammation in AT. Like obesity, chronic inflammation and MDs are prevalent in the elderly. The resident immune microenvironment is not only responsible for maintaining AT homeostasis but also plays a crucial role in stemming obesity and related MDs. Mounting evidence suggests that obesity promotes activation in resident T cells and macrophages. Additionally, inflammatory subsets of T cells and macrophages accumulated into the AT in combination with other immune cells maintain low-grade chronic inflammation. microRNAs (miRs) are small non-coding RNAs and a crucial contributing factor in maintaining immune response and obesity in AT. AT resident T cells, macrophages and adipocytes secrete various miRs and communicate with other cells to create a potential effect in metabolic organ crosstalk. AT resident macrophages and T cells-associated miRs have a prominent role in regulating obesity by targeting several signaling pathways. Further, miRs also emerged as important regulators of cellular senescence and aging. To this end, a clear link between miRs and longevity has been demonstrated that implicates their role in regulating lifespan and the aging process. Hence, AT and circulating miRs can be used as diagnostic and therapeutic tools for obesity and related disorders. In this review, we discuss how miRs function as biomarkers and impact obesity, chronic inflammation, and aging.

Physiology of the Weight-Reduced State and Its Impact on Weight Regain

Obesity is a chronic disease characterized by long duration, slow progression, and periods of remission and relapses. Despite the development of effective medical and surgical interventions and millions of people conducting tremendous personal efforts to manage their weight every year, recidivism remains a significant barrier to attaining long-term weight maintenance. This review aimed to explain the underlying physiology of the weight-reduced state including changes in energy balance, adipose tissue, genetic, environmental, and behavioral factors that may predispose individuals to weight regain following weight loss.

A perspective on diet, epigenetics and complex diseases: where is the field headed next?

Dietary factors can regulate epigenetic processes during life, modulating the intracellular pools of metabolites necessary for epigenetic reactions and regulating the activity of epigenetic enzymes. Their effects are strong during the prenatal life, when epigenetic patterns are written, allowing organogenesis. However, interactions between diet and the epigenome continue throughout life and likely contribute to the onset and progression of various complex diseases. Here, we review the contribution of dietary factors to the epigenetic changes observed in complex diseases and suggest future steps to better address this issue, focusing on neurobehavioral, neuropsychiatric and neurodegenerative disorders, cardiovascular diseases, obesity and Type 2 diabetes, cancer and inflammatory skin diseases.

Circulating miRNAs in girls with abdominal obesity: miR-221-3p as a biomarker of response to weight loss interventions

BACKGROUND

Recent studies have associated several microRNAs (miRNAs) with childhood obesity and energy homeostasis, suggesting that an individual miRNA profile could be used as an early predictor to estimate the response to weight loss interventions in the design of precision nutrition.

OBJECTIVE

To investigate associations between the expression of circulating adiposity-related miRNAs and the response to a weight loss intervention.

METHODS

A total of 51 Spanish girls (age 7-16 years) with abdominal obesity underwent 8 weeks of a multidisciplinary intervention for weight loss. Participants were stratified into two groups in accordance with changes in body mass index (BMI) standard deviation score: low-responders (LR) and high-responders (HR). The expression of 39 circulating miRNAs (c-miRNAs) was evaluated in plasma of all subjects before the intervention.

RESULTS

Six miRNAs were differentially expressed between LR and HR. However, after adjustment for Tanner stage, the association was maintained only for miR-126-3p and miR-221-3p with a higher expression in HR group compared to LR group. After the intervention, miR-221-3p expression decreased in all subjects with a significant difference in the change within groups. However, changes in miR-126-3p levels were not significant. The expression of miR-221-3p was positively correlated with body weight, BMI and waist circumference, and negatively correlated with quantitative insulin sensitivity check index.

CONCLUSIONS

Bioinformatic analysis evidenced that miR-221-3p participates in several obesity-related pathways, and more interestingly, this miRNA targets several candidate genes to childhood obesity according to DisGeNet database. Thus, miR-221-3p could be used for predicting the response to a multidisciplinary intervention for weight loss in young girls.

Evidence for correlations between BMI-associated SNPs and circRNAs

Circular RNAs (circRNAs) are regulators of processes like adipogenesis. Their expression can be modulated by SNPs. We analysed links between BMI-associated SNPs and circRNAs. First, we detected an enrichment of BMI-associated SNPs on circRNA genomic loci in comparison to non-significant variants. Analysis of sex-stratified GWAS data revealed that circRNA genomic loci encompassed more genome-wide significant BMI-SNPs in females than in males. To explore whether the enrichment is restricted to BMI, we investigated nine additional GWAS studies. We showed an enrichment of trait-associated SNPs in circRNAs for four analysed phenotypes (body height, chronic kidney disease, anorexia nervosa and autism spectrum disorder). To analyse the influence of BMI-affecting SNPs on circRNA levels in vitro, we examined rs4752856 located on hsa_circ_0022025. The analysis of heterozygous individuals revealed an increased level of circRNA derived from the BMI-increasing SNP allele. We conclude that genetic variation may affect the BMI partly through circRNAs.

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.

Epigenetics in Precision Nutrition

Precision nutrition is an emerging area of nutrition research, with primary focus on the individual variability in response to dietary and lifestyle factors, which are mainly determined by an individual’s intrinsic variations, such as those in genome, epigenome, and gut microbiome. The current research on precision nutrition is heavily focused on genome and gut microbiome, while epigenome (DNA methylation, non-coding RNAs, and histone modification) is largely neglected. The epigenome acts as the interface between the human genome and environmental stressors, including diets and lifestyle. Increasing evidence has suggested that epigenetic modifications, particularly DNA methylation, may determine the individual variability in metabolic health and response to dietary and lifestyle factors and, therefore, hold great promise in discovering novel markers for precision nutrition and potential targets for precision interventions. This review summarized recent studies on DNA methylation with obesity, diabetes, and cardiovascular disease, with more emphasis put in the relations of DNA methylation with nutrition and diet/lifestyle interventions. We also briefly reviewed other epigenetic events, such as non-coding RNAs, in relation to human health and nutrition, and discussed the potential role of epigenetics in the precision nutrition research.

Effects of a short-term cold exposure on circulating microRNAs and metabolic parameters in healthy adult subjects

This discovery study investigated in healthy subjects whether a short‐term cold exposure may alter circulating microRNAs and metabolic parameters and if co‐expression networks between these factors could be identified. This open randomized crossover (cold vs no cold exposure) study with blind end‐ point evaluation was conducted at 1 center with 10 healthy adult male volunteers. Wearing a cooling vest perfused at 14°C for 2 h reduced the local skin temperature without triggering shivering, increased norepinephrine and blood pressure while decreasing copeptin, C‐peptide and heart rate. Circulating microRNAs measured before and after wearing the cooling vest twice (4 time points) identified 196 mature microRNAs with excellent reproducibility over 72 h. Significant correlations of microRNA expression with copeptin, norepinephrine and C‐peptide were found. A co‐expression‐based microRNA‐microRNA network, as well as microRNA pairs displaying differential correlation as a function of temperature were also detected. This study demonstrates that circulating miRNAs are differentially expressed and coregulated upon cold exposure in humans, supporting their use as predictive and dynamic biomarkers of cardio‐metabolic disorders.

Estradiol-driven metabolism in transwomen associates with reduced circulating extracellular vesicle microRNA-224/452

OBJECTIVE

Sex steroid hormones like estrogens have a key role in the regulation of energy homeostasis and metabolism. In transwomen, gender-affirming hormone therapy like estradiol (in combination with antiandrogenic compounds) could affect metabolism as well. Given that the underlying pathophysiological mechanisms are not fully understood, this study assessed circulating estradiol-driven microRNAs (miRs) in transwomen and their regulation of genes involved in metabolism in mice.

METHODS

Following plasma miR-sequencing (seq) in a transwomen discovery (n = 20) and validation cohort (n = 30), we identified miR-224 and miR-452. Subsequent systemic silencing of these miRs in male C57Bl/6 J mice (n = 10) was followed by RNA-seq-based gene expression analysis of brown and white adipose tissue in conjunction with mechanistic studies in cultured adipocytes.

RESULTS

Estradiol in transwomen lowered plasma miR-224 and -452 carried in extracellular vesicles (EVs) while their systemic silencing in mice and cultured adipocytes increased lipogenesis (white adipose) but reduced glucose uptake and mitochondrial respiration (brown adipose). In white and brown adipose tissue, differentially expressed (miR target) genes are associated with lipogenesis (white adipose) and mitochondrial respiration and glucose uptake (brown adipose).

CONCLUSION

This study identified an estradiol-drive post-transcriptional network that could potentially offer a mechanistic understanding of metabolism following gender-affirming estradiol therapy.

Liquid Biopsy for Cancer Cachexia: Focus on Muscle-Derived microRNAs

Cancer cachexia displays a complex nature in which systemic inflammation, impaired energy metabolism, loss of muscle and adipose tissues result in unintentional body weight loss. Cachectic patients have a poor prognosis and the presence of cachexia reduces the tolerability of chemo/radio-therapy treatments and it is frequently the primary cause of death in advanced cancer patients. Early detection of this condition could make treatments more effective. However, early diagnostic biomarkers of cachexia are currently lacking. In recent years, although solid biopsy still remains the "gold standard" for diagnosis of cancer, liquid biopsy is gaining increasing interest as a source of easily accessible potential biomarkers. Moreover, the growing interest in circulating microRNAs (miRNAs), has made these molecules attractive for the diagnosis of several diseases, including cancer. Some muscle-derived circulating miRNA might play a pivotal role in the onset/progression of cancer cachexia. This topic is of great interest since circulating miRNAs might be easily detectable by means of liquid biopsies and might allow an early diagnosis of this syndrome. We here summarize the current knowledge on circulating muscular miRNAs involved in muscle atrophy, since they might represent easily accessible and promising biomarkers of cachexia.

Precision nutrition based on phenotypical traits and the (epi)genotype: nutrigenetic and nutrigenomic approaches for obesity care

PURPOSE OF REVIEW

The purpose of this article is to rationally review and critically appraise the current knowledge in the most relevant nongenetic and genetic factors influencing obesity predisposition. This information may be translated into the implementation of personalized nutrition approaches involving precision nutrigenetic and nutrigenomic strategies for obesity monitoring and weight management.

RECENT FINDINGS

The importance and influence of several nongenetic contributors to obesity onset and individual responses to weight-loss interventions have been highlighted including the role of age, sex or perinatal feeding and others related to an individual's lifestyle and modifiable. Nutrigenetic studies have analysed potential interactions between polymorphisms influencing energy homeostasis/body composition and dietary factors in relation to adiposity phenotypes and therapy responsiveness. A second approach comprises the Nutrigenomic analysis of gene expression modifications in response to the consumption of specific nutrients or dietary bioactive compounds, which may involve epigenetic mechanisms including deoxyribonucleic acid methylation and micro-ribonucleic acid expression profiles.

SUMMARY

Taken together, these findings encompass the importance of taking into account up-to-date advances in Nutrigenetic and Nutrigenomic hallmarks, globally analysing the risk of weight gain and related outcomes after following nutrition counselling, this contributing to improve obesity care considering phenotypical traits and the genetic make-up for precision obesity care.

Tissue and circulating microRNAs as biomarkers of response to obesity treatment strategies

BACKGROUND

Obesity, characterized by an increased amount of adipose tissue, is a metabolic chronic alteration which has reached pandemic proportion. Lifestyle changes are the first line therapy for obesity and a large variety of dietary approaches have demonstrated efficacy in promoting weight loss and improving obesity-related metabolic alterations. Besides diet and physical activity, bariatric surgery might be an effective therapeutic strategy for morbid obese patients. Response to weight-loss interventions is characterised by high inter-individual variability, which might involve epigenetic factors. microRNAs have critical roles in metabolic processes and their dysregulated expression has been reported in obesity.

AIM

The aim of this review is to provide a comprehensive overview of current studies evaluating changes in microRNA expression in obese patients undergoing lifestyle interventions or bariatric surgery.

RESULTS

A considerable number of studies have reported a differential expression of circulating microRNAs before and after various dietary and bariatric surgery approaches, identifying several candidate biomarkers of response to weight loss. Significant changes in microRNA expression have been observed at a tissue level as well, with entirely different patterns between visceral and subcutaneous adipose tissue. Interestingly, relevant differences in microRNA expression have emerged between responders and non-responders to dietary or surgical interventions. A wide variety of dysregulated microRNA target pathways have also been identified, helping to understand the pathophysiological mechanisms underlying obesity and obesity-related metabolic diseases.

CONCLUSIONS

Although further research is needed to draw firm conclusions, there is increasing evidence about microRNAs as potential biomarkers for weight loss and response to intervention strategies in obesity.

Mediterranean diet enriched in extra-virgin olive oil or nuts modulates circulating exosomal non-coding RNAs

PURPOSE

Exosomes are extracellular vesicles secreted by cells, which can transport different molecules, including nucleic acids. Dietary habits may induce gene regulation through the modulation of exosomal RNAs. We aimed at characterizing exosomal lncRNAs, mRNA and miRNAs modulation after a 1-year adherence to a low-fat diet (LFD) or to Mediterranean-based diets enriched in extra-virgin olive oil (MedDiet + EVOO) or in a mixture of nuts (MedDiet + Nuts).

METHODS

Plasma samples were collected, at baseline and after 1 year of dietary interventions, from 150 participants included in the PREDIMED study (Reus Center). LncRNAs, mRNAs and miRNAs were isolated from plasma exosomes and screened. RT-qPCR validation was performed for miRNAs.

RESULTS

Compared with LFD, 413 lncRNAs and 188 mRNAs, and 476 lncRNAs and 235 mRNAs were differentially modulated in response to the MedDiet + EVOO and MedDiet + Nuts interventions, respectively. In addition, after 1 year of dietary interventions, 26 circulating miRNAs were identified as differentially expressed between groups. After 1 year of intervention, 11 miRNAs significantly changed in LFD group, while 8 and 21 were modulated in response to the MedDiet enriched with EVOO or nuts, respectively. Bioinformatic analyses of differentially expressed miRNAs and their validated target genes suggest certain metabolic pathways are modulated by LFD (PI3K-Akt and AMPK), MedDiet + EVOO (PI3K-Akt, NF-kappa B, HIF-1, and insulin resistance), and MedDiet-Nuts (FoxO, PI3K-Akt, AMPK, p53 and HIF-1) interventions.

CONCLUSION

Results show that 1-year MedDiet + Nuts and MedDiet + EVOO dietary interventions modulate exosomal RNA content, with the former affecting a higher number of miRNAs. The modulation of exosomal RNAs could help explain how the adherence to a Mediterranean diet may lead to beneficial effects and deserves further investigation.

Fasting-mediated metabolic and toxicity reprogramming impacts circulating microRNA levels in humans

It is well-established that long-term fasting improves metabolic health, enhances the total antioxidant capacity and increases well-being. MicroRNAs oversee energy homeostasis and metabolic processes and are widely used as circulating biomarkers to identify the metabolic state. This study investigated whether the expression levels of twenty-four metabolism-associated microRNAs are significantly altered following long-term fasting and if these changes correlate with biochemical and redox parameters in the plasma. Thirty-two participants with an average BMI of 28 kg/m² underwent a 10-day fasting period with a daily intake of 250 kcal under medical supervision. RT-qPCR on plasma small-RNA extracts revealed that the levels of seven microRNAs (miR-19b-3p, miR-22-3p, miR-122-5p, miR-126-3p, miR-142-3p, miR-143-3p, and miR-145-5p) were significantly altered following fasting. Importantly, the expression levels of these microRNAs have been consistently shown to change in the exact opposite direction in pathological states including obesity, diabetes, nonalcoholic steatohepatitis, and cardiovascular disease. Linear regression analyses revealed that among the microRNAs analyzed, anti-inflammatory miR-146-5p expression displayed most correlations with the levels of different biochemical and redox parameters. In silico analysis of fasting-associated microRNAs demonstrated that they target pathways that are highly enriched for intracellular signaling such mTOR, FoxO and autophagy, as well as extracellular matrix (ECM) interactions and cell-senescence. Overall, these data are consistent with a model in which long-term fasting engages homeostatic mechanisms associated with specific microRNAs to improve metabolic signaling regardless of health status.

A Traditional Korean Diet Alters the Expression of Circulating MicroRNAs Linked to Diabetes Mellitus in a Pilot Trial

The traditional Korean diet (K-diet) is considered to be healthy and circulating microRNAs (miRs) have been proposed as useful markers or targets in diet therapy. We, therefore, investigated the metabolic influence of the K-diet by evaluating the expression of plasma and salivary miRs. Ten women aged 50 to 60 years were divided into either a K-diet or control diet (a Westernized Korean diet) group. Subjects were housed in a metabolic unit-like condition during the two-week dietary intervention. Blood and saliva samples were collected before and after the intervention, and changes in circulating miRs were screened by an miR array and validated by individual RT-qPCRs. In the K-diet group, eight plasma miRs were down-regulated by array (p < 0.05), out of which two miRs linked to diabetes mellitus, hsa-miR26a-5p and hsa-miR126-3p, were validated (p < 0.05). Among five down-regulated salivary miRs, hsa-miR-92-3p and hsa-miR-122a-5p were validated, which are associated with diabetes mellitus, acute coronary syndrome and non-alcoholic fatty liver disease. In the control diet group, validated were down-regulated plasma hsa-miR-25-3p and salivary hsa-miR-31-5p, which are associated with diabetes mellitus, adipogenesis and obesity. The K-diet may influence the metabolic conditions associated with diabetes mellitus, as evidenced by changes in circulating miRs, putative biomarkers for K-diet.

Crosstalk between circulating microRNAs and chronotypical features in subjects with metabolic syndrome

Circulating microRNAs (miRNAs) are valuable biomarkers that may provide important insight into the pathogenesis of metabolic syndrome (MetS). Moreover, there is an association between chronotypical characteristics and MetS predisposition. Considering that expression of some miRNAs is circadian-rhythm-dependent, the aim of this study was to investigate the circulating miRNA profile in subjects with and without MetS in association with chronotype. The expression of 86 metabolic syndrome-related miRNAs was investigated in the plasma of 21 subjects with MetS and in 82 subjects without MetS using miRCURY LNA miRNA PCR System technology. Chronotype was assessed using the Horne and Östberg Morningness-Eveningness Questionnaire. Bioinformatic analyses were performed to explore the target genes and biological pathways regulated by the selected miRNAs. Subjects with MetS were more often evening chronotype compared to non-MetS controls. Additionally, four miRNAs (miR-140-3p, miR-150-5p, miR-375, and miR-29 c-3p) demonstrated interaction with MetS and chronotype. Interestingly, the target genes of these four miRNAs participate in pathways related to the circadian clock. In conclusion, we identified four circulating miRNAs whose circulating levels could interact with MetS and chronotype.

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.