MicroRNA -143 and -223 in obesity

Adipose-derived miRNAs as potential biomarkers for predicting adulthood obesity and its complications: A systematic review and bioinformatic analysis

Adipose tissue is the first and primary target organ of obesity and the main source of circulating miRNAs in patients with obesity. This systematic review aimed to analyze and summarize the generation and mechanisms of adipose-derived miRNAs and their role as early predictors of various obesity-related complications. Literature searches in the PubMed and Web of Science databases using terms related to miRNAs, obesity, and adipose tissue. Pre-miRNAs from the Human MicroRNA Disease Database, known to regulate obesity-related metabolic disorders, were combined for intersection processing. Validated miRNA targets were sorted through literature review, and enrichment analysis using the Kyoto Encyclopedia of Genes and Genomes via the KOBAS online tool, disease analysis, and miRNA transcription factor prediction using the TransmiR v. 2.0 database were also performed. Thirty miRNAs were identified using both obesity and adipose secretion as criteria. Seventy-nine functionally validated targets associated with 30 comorbidities of these miRNAs were identified, implicating pathways such as autophagy, p53 pathways, and inflammation. The miRNA precursors were analyzed to predict their transcription factors and explore their biosynthesis mechanisms. Our findings offer potential insights into the epigenetic changes related to adipose-driven obesity-related comorbidities.

Expression and Clinical Significance of Plasma miR-223 in Patients with Diabetic Nephropathy

Background

MicroRNA-223 (miR-223) is associated with diabetes and kidney diseases and serves as a novel marker for diagnosing diabetic kidney disease (DKD). This study was conducted to investigate the plasma expression of miR-223 and its clinical significance in type 2 diabetes (T2DM) and diabetic nephropathy (DN) patients.

Methods

In this research, 20 patients with T2DM and DN, 19 patients with T2DM, and 17 healthy volunteers were finally enrolled. miR-223 expression was detected by quantitative real-time PCR (qPCR), and the diagnostic value of miR-223 in DN was further analyzed.

Results

miR-223 was downregulated in the DN group compared to that in the T2DM group (P=0.031) and the control group (P < 0.001). Pearson's correlation analysis showed a negative correlation of miR-223 levels with an albumin-creatinine ratio (ACR) (r = -0.481; P=0.044), urine β2-microglobulin (β2-MG) (r = -0.494; P=0.037), urine α1-microglobulin (α1-MG) (r = -0.537; P=0.022), creatinine (Cr) (r = -0.664; P < 0.01), cystatin C (Cyc-C) (r = -0.553; P=0.017), and glycosylated hemoglobin (HbA1c) (r = -0.761; P < 0.01). The findings of a binary regression analysis indicated that miR-223, ACR, Cr, and α1-MG were the risk factors for DN (OR: 2.019, 1.166, 1.031, and 1.031; all P < 0.05). Furthermore, miR-223 had a favorable diagnostic value for DN (AUC: 0.752; sensitivity: 0.722; specificity: 0.842) (2.5 was utilized as the diagnostic cutoff point).

Conclusion

miR-223 was lowly expressed in DN patients, and the evaluation of miR-223 may be a good approach for diagnosing DN.

Genetic Variants Identified by Whole Exome Sequencing in a Large Italian Family with High Plasma Levels of Factor VIII and Von Willebrand Factor

High plasma levels of factor VIII (FVIII) and von Willebrand factor (VWF) have been indicated as independent risk factors for venous thromboembolism. However, the genetic factors responsible for their increase remain poorly known. In a large Italian family with high FVIII/VWF levels and thrombotic episodes, whole exome sequencing (WES) was performed on 12 family members to identify variants/genes involved in FVIII/VWF increase. Twenty variants spread over a 8300 Kb region on chromosome 5 were identified in 12 genes, including the low frequency rs13158382, located upstream of the MIR143/145 genes, which might affect miR-143/145 transcription or processing. The expression of miR-143/145 and VWF mRNA were evaluated in the peripheral blood mononuclear cells of six family members. Members with the variant (n = 3) showed lower levels of both miRNAs and higher levels of VWF mRNA compared to members without the variant (n = 3). An analysis of genetic and expression data from a larger cohort of individuals from the 1000 Genomes and GEUVADIS project confirmed a statistically significant reduction (p-value = 0.023) in miR-143 in heterozygous (n = 35) compared to homozygous wild-type individuals (n = 386). This family-based study identified a new genetic variant potentially involved in VWF increase by affecting miR-143/145 expression.

The novel importance of miR-143 in obesity regulation

Obesity and substantially increased risk of metabolic diseases have become a global epidemic. microRNAs have attracted a great deal of attention as a potential therapeutic target for obesity. MiR-143 has been known to specifically promote adipocyte differentiation by downregulating extracellular signal-regulated kinase 5. Our latest study found that miR-143 knockout is against diet-induced obesity by promoting brown adipose tissue thermogenesis and inhibiting white adipose tissue adipogenesis. Moreover, LPS- or IL-6-induced inhibition of miR-143 expression in brown adipocytes promotes thermogenesis by targeting adenylate cyclase 9. In this review, we will summarize the expression and functions of miR-143 in different tissues, the influence of obesity on miR-143 in various tissues, the important role of adipose-derived miR-143 in the development of obesity, the role of miR-143 in immune cells and thermoregulation and discuss the potential significance and application prospects of miR-143 in obesity management.

Elevated miR-143 and miR-34a gene expression in human visceral adipose tissue are associated with insulin resistance in non-diabetic adults: a cross-sectional study

OBJECTIVE

We aimed to evaluate the association of miR-143 and miR-34a expression in human visceral (VAT) and subcutaneous (SAT) adipose tissues with insulin resistance (IR).

METHODS

VAT and SAT were obtained from 176 participants without diabetes. miR-143 and miR-34a expressions in VAT and SAT were measured using qRT-PCR. Fasting serum insulin and glucose concentration, homeostatic model assessment of IR index (HOMA-IR) and β-cell function (HOMA-B), and quantitative insulin-sensitivity check index (QUICKI) were calculated.

RESULTS

After adjustment for age, sex and body mass index (BMI), VAT miR-143 expression was positively associated with fasting plasma glucose (FPG), insulin, and HOMA-IR, and negatively associated with HOMA-B and QUICKI. miR-34a expression in VAT was directly associated with FPG, insulin, and HOMA-IR and negatively associated with QUICKI. In SAT, miR-34a expression was positively associated with insulin and negatively associated with QUICKI. The interaction terms of HOMA-IR and BMI categories were significant for both miR gene expressions in VAT. After stratifying participants based on BMI, the association of miR-143 and miR-34a expressions in VAT with IR indices remained significant only in obese patients.

CONCLUSION

miR-143 and miR-34a expressions in VAT were independent predictors of IR in people without diabetes, and that this association was conditional on the degree of obesity.

LEVEL OF EVIDENCE

Level of evidence III, cross-sectional analytic study.

miR-143-null Is against Diet-Induced Obesity by Promoting BAT Thermogenesis and Inhibiting WAT Adipogenesis

Excessive energy intake is the main cause of obesity, and stimulation of brown adipose tissue (BAT) thermogenesis has emerged as an attractive tool for anti-obesity. Although miR-143 has been reported to promote white adipocyte differentiation, its role in BAT remains unclear. In our study, we found that during HFD-induced obesity, the expression of miR-143 in BAT was significantly reduced, and the expression of miR-143 in WAT first increased and then decreased. Knockout (KO) of miR-143 with CRISPR/Cas9 did not affect the energy metabolism of normal diet fed mice and brown adipocyte differentiation but inhibited the differentiation of white adipocytes. Importantly, during high fat diet-induced obesity, miR-143KO significantly reduced body weight, and improved energy expenditure, insulin sensitivity, and glucose tolerance. Further exploration showed that miR-143KO reduced the weight of adipose tissue, promoted mitochondrial number and functions, induced thermogenesis and lipolysis of BAT, increased lipolysis, and inhibited lipogenesis of white adipose tissue (WAT). Our study considerably improves our collective understanding of the function of miR-143 in adipose tissue and its potential significance in anti-obesity and provides a new avenue for the management of obesity through the inhibition of miR-143 in BAT and WAT.

Analysis of the miRNA expression from the adipose tissue surrounding the adrenal neoplasia

Background

Primary aldosteronism (PA) is characterized by several metabolic changes such as insulin resistance, metabolic syndrome, and adipose tissue (AT) inflammation. Mi(cro)RNAs (miRNAs) are a class of non-coding small RNA molecules known to be critical regulators in several cellular processes associated with AT dysfunction. The aim of this study was to evaluate the expression of some miRNAs in visceral and subcutaneous AT in patients undergoing adrenalectomy for aldosterone-secreting adrenal adenoma (APA) compared to the samples of AT obtained in patients undergoing adrenalectomy for non-functioning adrenal mass (NFA).

Methods

The quantitative expression of selected miRNA using real-time PCR was analyzed in surrounding adrenal neoplasia, peri-renal, and subcutaneous AT samples of 16 patients with adrenalectomy (11 patients with APA and 5 patients with NFA).

Results

Real-time PCR cycles for miRNA-132, miRNA-143, and miRNA-221 in fat surrounding adrenal neoplasia and in peri-adrenal AT were significantly higher in APA than in patients with NFA. Unlike patients with NFA, miRNA-132, miRNA-143, miRNA-221, and miRNA-26b were less expressed in surrounding adrenal neoplasia AT compared to subcutaneous AT in patients with APA.

Conclusion

This study, conducted on tissue expression of miRNAs, highlights the possible pathophysiological role of some miRNAs in determining the metabolic alterations in patients with PA.

Stool microRNA profiles reflect different dietary and gut microbiome patterns in healthy individuals

OBJECTIVES

MicroRNA (miRNA) profiles have been evaluated in several biospecimens in relation to common diseases for which diet may have a considerable impact. We aimed at characterising how specific diets are associated with the miRNome in stool of vegans, vegetarians and omnivores and how this is reflected in the gut microbial composition, as this is still poorly explored.

DESIGN

We performed small RNA and shotgun metagenomic sequencing in faecal samples and dietary recording from 120 healthy volunteers, equally distributed for the different diets and matched for sex and age.

RESULTS

We found 49 miRNAs differentially expressed among vegans, vegetarians and omnivores (adj. p <0.05) and confirmed trends of expression levels of such miRNAs in vegans and vegetarians compared with an independent cohort of 45 omnivores. Two miRNAs related to lipid metabolism, miR-636 and miR-4739, were inversely correlated to the non-omnivorous diet duration, independently of subject age. Seventeen miRNAs correlated (|rho|>0.22, adj. p <0.05) with the estimated intake of nutrients, particularly animal proteins, phosphorus and, interestingly, lipids. In omnivores, higher Prevotella and Roseburia and lower Bacteroides abundances than in vegans and vegetarians were observed. Lipid metabolism-related miR-425-3p and miR-638 expression levels were associated with increased abundances of microbial species, such as Roseburia sp. CAG 182 and Akkermansia muciniphila, specific of different diets. An integrated analysis identified 25 miRNAs, 25 taxa and 7 dietary nutrients that clearly discriminated (area under the receiver operating characteristic curve=0.89) the three diets.

CONCLUSION

Stool miRNA profiles are associated with specific diets and support the role of lipids as a driver of epigenetic changes and host-microbial molecular interactions in the gut.

Hydroalcoholic extract of dill and aerobic training prevents high-fat diet-induced metabolic risk factors by improving miR-33 and miR-223 expression in rat liver

Exercise training and medicinal herb supplementation may improve microRNAs (miRNAs) expression associated with obesity. This study aimed to assess the effects of 10 weeks of aerobic training (AT) and dill extract (DE) on miR-33 and miR-223 expression of liver in high-fat diet (HFD)-induced obese rats. Forty male Wistar rats were fed a defined high-fat (n = 32) and standard (n = 8, nonobese control [NC]) diet. After obesity induction, obese rats were randomly allocated to four groups: AT, DE, AT + DE, and obese control (OC). Rats were euthanized and plasma and liver tissue samples were collected after the intervention. The liver expression of miR-33 was lower in the AT, DE, AT + DE, and NC groups compared with the OC group. Also, the liver miR-223 expression was higher in the AT, DE, AT + DE, and NC groups compared with the OC group. Moreover, the liver expression of miR-223 in the AT + DE group was higher compared with the AT and DE groups. The AT, DE, AT + DE, and NC groups had lower liver TC compared with the OC group. Also, the plasma level of apolipoprotein B (Apo B) was significantly lower, and liver HDL-C was significantly higher in the AT + DE and NC groups compared with the OC group. These findings show that long-term AT combined with the intake of DE may improve the plasma levels of Apo B, and TC and HDL-C levels in the liver, which is probably due to AT and DE positive effects on miR-33 and miR-223 in the liver of obese rats. PRACTICAL APPLICATIONS: Aerobic training reduces overweight and obesity health problems, however, the duration and intensity of the exercise training distinguish between individuals. We used an integrated approach combining pharmacological and non-pharmacological as a medical strategy to prevent HFD-induced metabolic injury in obese rats. The present results discovered that a combination of AT + DE intervention improves the miR-33 and miR-223 in the liver of obese rats.

microRNAs in Human Adipose Tissue Physiology and Dysfunction

In recent years, there has been a large amount of evidence on the role of microRNA (miRNA) in regulating adipose tissue physiology. Indeed, miRNAs control critical steps in adipocyte differentiation, proliferation and browning, as well as lipolysis, lipogenesis and adipokine secretion. Overnutrition leads to a significant change in the adipocyte miRNOME, resulting in adipose tissue dysfunction. Moreover, via secreted mediators, dysfunctional adipocytes may impair the function of other organs and tissues. However, given their potential to control cell and whole-body energy expenditure, miRNAs also represent critical therapeutic targets for treating obesity and related metabolic complications. This review attempts to integrate present concepts on the role miRNAs play in adipose tissue physiology and obesity-related dysfunction and data from pre-clinical and clinical studies on the diagnostic or therapeutic potential of miRNA in obesity and its related complications.

MicroRNAs: The Link between the Metabolic Syndrome and Oncogenesis

Metabolic syndrome (MetS) represents a cluster of disorders that increase the risk of a plethora of conditions, in particular type two diabetes, cardiovascular diseases, and certain types of cancers. MetS is a complex entity characterized by a chronic inflammatory state that implies dysregulations of adipokins and proinflammatory cytokins together with hormonal and growth factors imbalances. Of great interest is the implication of microRNA (miRNA, miR), non-coding RNA, in cancer genesis, progression, and metastasis. The adipose tissue serves as an important source of miRs, which represent a novel class of adipokines, that play a crucial role in carcinogenesis. Altered miRs secretion in the adipose tissue, in the context of MetS, might explain their implication in the oncogenesis. The interplay between miRs expressed in adipose tissue, their dysregulation and cancer pathogenesis are still intriguing, taking into consideration the fact that miRNAs show both carcinogenic and tumor suppressor effects. The aim of our review was to discuss the latest publications concerning the implication of miRs dysregulation in MetS and their significance in tumoral signaling pathways. Furthermore, we emphasized the role of miRNAs as potential target therapies and their implication in cancer progression and metastasis.

The miRNA expression profile directly reflects the energy metabolic differences between slow and fast muscle with nutritional regulation of the Chinese perch (Siniperca chuatsi)

Fish skeletal muscles are composed of two distinct types, slow and fast muscles, and they play important roles in maintaining the body's movement and energy metabolism. The two types of muscle are easy to separate, so they are often used as the model system for studies on their physiological and functional characteristics. In this study, we revealed that the carbohydrate and lipid metabolic KEGG pathways are different between slow and fast muscles of Chinese perch with transcriptome analysis. In fast muscle, glucose metabolism was catabolic with higher glycolysis capacity, while in slow muscle, glucose metabolism was anabolic with more glycogen synthesis. In addition, oxidative metabolism in slow muscle was stronger than that in fast muscle. By analyzing the expression levels of 40 miRNAs involved in metabolism in the muscles of Chinese perch, 18 miRNAs were significantly upregulated and 7 were significantly downregulated in slow muscle compared with fast muscle. Based on functional enrichment analysis of their target genes, the differential expression levels of 17 miRNAs in slow and fast muscles were reflected in their carbohydrate and lipid metabolism. Among these, 15 miRNAs were associated with carbohydrate metabolism, and 6 miRNAs were associated with lipid metabolism. After 3 days of starvation, the expression levels of 15 miRNAs involved in glucose metabolism in fast and slow muscles increased. However, after 7 days of starvation, the mRNA levels of miR-22a, miR-23a, miR-133a-3p, miR-139, miR-143, miR-144, miR-181a and miR-206 decreased to basal levels. Our data suggest that the possible reason for the difference in glucose and lipid metabolism is that more miRNAs inhibit the expression of target genes in slow muscle.

High fructose exposure modifies the amount of adipocyte-secreted microRNAs into extracellular vesicles in supernatants and plasma

Background

High fructose exposure induces metabolic and endocrine responses in adipose tissue. Recent evidence suggests that microRNAs in extracellular vesicles are endocrine signals secreted by adipocytes. Fructose exposure on the secretion of microRNA by tissues and cells is poorly studied. Thus, the aim of this study was to evaluate the effect of fructose exposure on the secretion of selected microRNAs in extracellular vesicles from 3T3-L1 cells and plasma from Wistar rats.

Methods

3T3-L1 cells were exposed to 550 µM of fructose or standard media for four days, microRNAs levels were determined in extracellular vesicles of supernatants and cells by RT-qPCR. Wistar rats were exposed to either 20% fructose drink or tap water for eight weeks, microRNAs levels were determined in extracellular vesicles of plasma and adipose tissue by RT-qPCR.

Results

This study showed that fructose exposure increased the total number of extracellular vesicles released by 3T3-L1 cells (p = 0.0001). The levels of miR-143-5p were increased in extracellular vesicles of 3T3-L1 cells exposed to fructose (p = 0.0286), whereas miR-223-3p levels were reduced (p = 0.0286). Moreover, in plasma-derived extracellular vesicles, miR-143-5p was higher in fructose-fed rats (p = 0.001), whereas miR-223-3p (p = 0.022), miR-342-3p (p = 0.0011), miR-140-5p (p = 0.0129) and miR-146b-5p (p = 0.0245) were lower.

Conclusion

Fructose exposure modifies the levels of microRNAs in extracellular vesicles in vitro and in vivo. In particular, fructose exposure increases miR-143-5p, while decreases miR-223-3p and miR-342-3p.

Epigenetics, microRNA and Metabolic Syndrome: A Comprehensive Review

Epigenetics refers to the DNA chemistry changes that result in the modification of gene transcription and translation independently of the underlying DNA coding sequence. Epigenetic modifications are reported to involve various molecular mechanisms, including classical epigenetic changes affecting DNA methylation and histone modifications and small RNA-mediated processes, particularly that of microRNAs. Epigenetic changes are reversible and are closely interconnected. They are recognised to play a critical role as mediators of gene regulation, and any alteration in these mechanisms has been identified to mediate various pathophysiological conditions. Moreover, genetic predisposition and environmental factors, including dietary alterations, lifestyle or metabolic status, are identified to interact with the human epigenome, highlighting the importance of epigenetic factors as underlying processes in the aetiology of various diseases such as MetS. This review will reflect on how both the classical and microRNA-regulated epigenetic changes are associated with the pathophysiology of metabolic syndrome. We will then focus on the various aspects of epigenetic-based strategies used to modify MetS outcomes, including epigenetic diet, epigenetic drugs, epigenome editing tools and miRNA-based therapies.

Modulations of obesity-related microRNAs after exercise intervention: a systematic review and bioinformatics analysis

Obesity is one of the prevalent health-threatening conditions; however, it is preventable by lifestyle interventions such as exercise. The molecular mechanisms underlying physiological adaptation to physical activity are not fully understood. It has been documented that both intracellular and extracellular (circulating) microRNAs (miRNAs) are involved in both obesogenic and exercise adaptation mechanisms. We aimed to conduct a systematic review of publications that examined the effect of exercise on the expression of miRNAs in individuals with obesity. In addition, bioinformatics analysis was performed on most repetitive miRNAs. PubMed, Scopus, and Google Scholar were searched with relevant keywords. We only included studies that utilized exercise as a modality for the health management of human subjects with obesity to evaluate the changes in expression of obesity-related miRNAs. Through checking of 211 retrieved articles, we reached 12 eligible studies. Some studies reported a statistically significant correlation between the change of miRNAs and clinical parameters such as body mass index and fasting glucose. In silico analysis of most repetitive miRNAs i.e. miR-126, miR-21, miR-146a, miR-221, and miR-223 resulted in the molecular signaling pathways that potentially involve in cellular adaption to exercise in people with obesity. miRNAs partake in health-related benefits of physical activity on obesity-associated cellular and molecular phenomena. However, our understanding of the exact mechanism is still in its infancy. Consistently, the clinicians waiting for the result of more integrated experiments to develop a miRNAs panel as a predictive biomarker of exercise in patients with obesity.

MicroRNA Expression Profiles in the Subcutaneous Adipose Tissues of Morbidly Obese Chinese Women

INTRODUCTION

Obesity is a main global health issue and an outstanding cause of morbidity and mortality. Exploring miRNA profiling may help further studies on obesity.

METHODS

Three morbidly obese and 5 normal-weight Chinese women were enrolled in the microarray testing group. Abdominal subcutaneous adipose tissue (SAT) samples were excised. Total RNAs including miRNAs were extracted. Affymetrix GeneChip miRNA 4.0 Array was used to compare the expression profiles of miRNAs between the 2 groups. Two algorithms, miRanda and TargetScan, were used to predict target messenger RNAs (mRNAs). Bioinformatics analysis was then done based on the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. The sample sizes were further expanded to 8 morbidly obese and 9 normal-weight subjects, and quantitative real-time PCR (qRT-PCR) was utilized to verify the expression of differential miRNAs and target genes.

RESULTS

As per the microarray assay, 58 miRNAs were differentially expressed in the SAT from the morbidly obese and normal-weight groups (Fold >4, p < 0.01, FDR <0.05); 54 of these were downregulated and 4 were upregulated in morbidly obese subjects. A total of 1,333 target genes were jointly predicted by miRanda and TargetScan. Further bioinformatics analysis showed that the differential miRNAs were involved in 269 significant biological functions and 89 significant signaling pathways. The validation experiment by qRT-PCR showed that the expression levels of miRNA-143-5p, miRNA-143-3p, miRNA-145-5p, and let-7a-5p were downregulated in morbidly obese subjects, consistent with the microarray detection. High-mobility group A2 (HMGA2), a target gene of the downregulated miRNA let-7a-5p, was first found to be upregulated 3.19-fold in the SAT of morbidly obese Chinese women when compared to normal-weight controls.

CONCLUSIONS

MiRNA downregulation is a hallmark of intact SAT in a morbidly obese state. Transcription (DNA-dependent), small-molecule metabolic processes, the MAPK signaling pathway, and cancer-related pathways may play important roles in the occurrence and development of obesity. For the first time, we proved that HMGA2, a target gene of let-7a-5p, is upregulated in the SAT of morbidly obese Chinese women.

The expression profile and role of non-coding RNAs in obesity

Latest years have experienced a dramatic upsurge in the knowledge about the function of non-coding transcripts in the determination of diverse human phenotypes including obesity. Several miRNAs and lncRNAs participate in the regulation of metabolic pathways leading to obesity. Several lncRNAs such as Mist, lincIRS2, lncRNA-p5549, H19, GAS5 and SNHG9 have been shown to be down-regulated in adipose tissues or other biological samples in the obese human or animal subjects. On the other hand, Meg3, Plnc1, Blnc1, AC092834.1, TINCR and PVT1 are among up-regulated lncRNAs in the obese subjects. Tens of miRNAs have differential expression between obese and non-obese subjects or between mature adipocytes and pre-adipocytes. Understanding the molecular mechanism of involvement of non-coding RNAs in the pathobiology of obesity would simplify design of therapeutic choices for protecting against obesity and its related comorbidities. We explain the available literature on the function of these transcripts in the pathobiology of obesity.

Regulatory microRNAs in Brown, Brite and White Adipose Tissue

MicroRNAs (miRNAs) constitute a class of short noncoding RNAs which regulate gene expression by targeting messenger RNA, inducing translational repression and messenger RNA degradation. This regulation of gene expression by miRNAs in adipose tissue (AT) can impact on the regulation of metabolism and energy homeostasis, particularly considering the different types of adipocytes which exist in mammals, i.e., white adipocytes (white AT; WAT), brown adipocytes (brown AT; BAT), and inducible brown adipocytes in WAT (beige or brite or brown-in-white adipocytes). Indeed, an increasing number of miRNAs has been identified to regulate key signaling pathways of adipogenesis in BAT, brite AT, and WAT by acting on transcription factors that promote or inhibit adipocyte differentiation. For example, MiR-328, MiR-378, MiR-30b/c, MiR-455, MiR-32, and MiR-193b-365 activate brown adipogenesis, whereas MiR-34a, MiR-133, MiR-155, and MiR-27b are brown adipogenesis inhibitors. Given that WAT mainly stores energy as lipids, whilst BAT mainly dissipates energy as heat, clarifying the effects of miRNAs in different types of AT has recently attracted significant research interest, aiming to also develop novel miRNA-based therapies against obesity, diabetes, and other obesity-related diseases. Therefore, this review presents an up-to-date comprehensive overview of the role of key regulatory miRNAs in BAT, brite AT, and WAT.

Altered Regulation of adipomiR Editing with Aging

Adipose dysfunction with aging increases risk to insulin resistance and other chronic metabolic diseases. We previously showed functional changes in microRNAs involved in pre-adipocyte differentiation with aging resulting in adipose dysfunction. However, the mechanisms leading to this dysfunction in microRNAs in adipose tissue (adipomiRs) during aging are not well understood. We determined the longitudinal changes in expression of adipomiRs and studied their regulatory mechanisms, such as miRNA biogenesis and editing, in an aging rodent model, with Fischer344 × Brown-Norway hybrid rats at ages ranging from 3 to 30 months (male/females, n > 8). Expression of adipomiRs and their edited forms were determined by small-RNA sequencing. RT-qPCR was used to measure the mRNA expression of biogenesis and editing enzymes. Sanger sequencing was used to validate editing with aging. Differential expression of adipomiRs involved in adipocyte differentiation and insulin signaling was altered with aging. Sex- and age-specific changes in edited adipomiRs were observed. An increase in miRNA biogenesis and editing enzymes (ADARs and their splice variants) were observed with increasing age, more so in female than male rats. The adipose dysfunction observed with age is attributed to differences in editing of adipomiRs, suggesting a novel regulatory pathway in aging.

Four-microRNA signature for detection of type 2 diabetes

BACKGROUND

Sensitive, novel, and accurate biomarkers for the detection of physiological changes in type 2 diabetes (T2DM) at an early stage are urgently needed.

AIM

To build a multi-parameter diagnostic model for the early detection of T2DM.

METHODS

MiR-148b, miR-223, miR-130a, and miR-19a levels were detected by real-time polymerase chain reaction in serum of healthy controls, individuals with impaired glucose regulation, and T2DM patients. The diagnostic value of miR-148b, miR-223, miR-130a, and miR-19a, alone or in combination, was analyzed.

RESULTS

The area under the curve (AUC) of miR-223, which had the best diagnostic value for discriminating the impaired glucose regulation and T2DM groups, was 0.84, and the sensitivity and specificity were 73.37% and 81.37%, respectively. The AUC of the four-miRNA signature was 0.90, and the sensitivity and specificity were 78.82% and 88.23%, respectively. In the validation set, the AUC was 0.88, and the sensitivity and specificity were 78.36% and 87.63%, respectively.

CONCLUSION

In summary, we have built a multi-parameter diagnostic model consisting of miR-148b, miR-223, miR-130a, and miR-19a for the detection of T2DM. It may be a potential tool for the early detection of T2DM.

Circulating microRNA expression profiling in young obese Korean women

BACKGROUND/OBJECTIVES

This study investigates correlations between circulating microRNAs (miRNAs) and obesity-related parameters among young women (aged 20–30 years old) in Korea.

SUBJECTS/METHODS

We analyzed TaqMan low density arrays (TLDAs) of circulating miRNAs in 9 lean (body mass index [BMI] < 25 kg/m²) and 15 obese (BMI > 25 kg/m²) women. We also performed gene ontology (GO) analyses of the biological functions of predicted miRNA target genes, and clustered the results using the database for annotation, visualization and integrated discovery.

RESULTS

The TLDA cards contain 754 human miRNAs; of these, the levels of 8 circulating miRNAs significantly declined (> 2-fold) in obese subjects compared with those in lean subjects, including miR-1227, miR-144-5p, miR-192, miR-320, miR-320b, miR-484, miR-324-3p, and miR-378. Among them, miR-484 and miR-378 displayed the most significant inverse correlations with BMI (miR-484, r = −0.5484, P = 0.0056; miR-378, r = −0.5538, P = 0.0050) and visceral fat content (miR-484, r = −0.6141, P = 0.0014; miR-378, r = −0.6090, P = 0.0017). GO analysis indicated that genes targeted by miR-484 and miR-378 had major roles in carbohydrate and lipid metabolism.

CONCLUSION

Our result showed the differentially expressed circulating miRNAs in obese subjects compared to lean subjects. Although the mechanistic study to reveal the causal role of miRNAs remains, these miRNAs may be novel biomarkers for obesity.

Mapping Research in the Obesity, Adipose Tissue, and MicroRNA Field: A Bibliometric Analysis

Recent studies have investigated the control of adipose tissue expansion and inflammatory process by microRNAs (miRNAs). These two processes are of great interest because both are associated with obesity and metabolic syndrome. However, despite the great relevance of the role of miRNAs in obesity and adipose tissue, no qualitative and quantitative analysis on the subject has been performed. Thus, we aimed to examine global research activity and current trends with respect to the interaction between obesity, adipose tissue and miRNAs through a bibliometric analysis. This research was performed on the Scopus database for publications containing miRNA, obesity, and adipose tissue keyword combinations. In total, 898 articles were analyzed and the most frequently occurring keywords were selected and clustered into three well-defined groups. As a result, first group of keywords pointed to the research area on miRNAs expressed in obesity-associated diseases. The second group demonstrated the regulation of the adipogenesis process by miRNAs, while the third group highlighted brown adipose tissue and thermogenesis as one of the latest global research trends related to the theme. The studies selected in this paper describe the expression and performance of different miRNAs in obesity and comorbidities. Most studies have focused on identifying miRNAs and signaling pathways associated with obesity, type 2 diabetes mellitus, and cardiovascular disease. Thus, the miRNA profile for these diseases may be used as biomarkers and therapeutic targets in the prevention and treatment of obesity-associated diseases.

Serum Levels of miR-143 Predict Survival in Critically Ill Patients

Background and Aims

Recent data suggested a potential role of miR-143 as a biomarker for systemic inflammation and infection. However, its role in critical illness and sepsis is only poorly understood.

Methods

We determined circulating levels of miR-143 in 218 critically ill patients, of which 135 fulfilled sepsis criteria, and compared them to 76 healthy controls. Results were correlated with clinical records.

Results

In the total cohort of critically ill patients from a medical intensive care unit (ICU), miR-143 serum levels tended to be lower compared to healthy control samples, but this difference did not reach statistical significance. In ICU patients, serum levels of miR-143 were independent of disease etiology, including the presence of sepsis, or severity of disease. Importantly, low miR-143 serum levels were associated with an unfavorable short- and long-term prognosis in ICU patients. Our study identified different optimal cut-off values at which low miR-143 serum levels predicted mortality with a high diagnostic accuracy. In line with this, concentrations of circulating miR-143 correlated with markers of organ failure such as creatinine, bilirubin, or lactate in our cohort of critically ill patients.

Conclusion

Low miR-143 serum levels are indicative for an unfavorable short- and long-term prognosis in critically ill patients admitted to a medical ICU. Our data suggest a previously unrecognized role for miR-143 measurements as a novel prognostic marker in critically ill patients.

Post-transcriptional markers associated with clinical complications in Type 1 and Type 2 diabetes mellitus

The delayed diagnosis and the inadequate treatment of diabetes increase the risk of chronic complications. The study of regulatory molecules such as miRNAs can provide expression profiles of diabetes and diabetes complications. We evaluated the mononuclear cell miRNA profiles of 63 Type 1 and Type 2 diabetes patients presenting or not microvascular complications, and 40 healthy controls, using massive parallel sequencing. Gene targets, enriched pathways, dendograms and miRNA-mRNA networks were performed for the differentially expressed miRNAs. Six more relevant miRNAs were validated by RT-qPCR and data mining analysis. MiRNAs associated with specific complications included: i) neuropathy (miR-873-5p, miR-125a-5p, miR-145-3p and miR-99b-5p); ii) nephropathy (miR-1249-3p, miR-193a-5p, miR-409-5p, miR-1271-5p, miR-501-3p, miR-148b-3p and miR-9-5p); and iii) retinopathy (miR-143-3p, miR-1271-5p, miR-409-5p and miR-199a-5p). These miRNAs mainly targeted gene families and specific genes associated with advanced glycation end products and their receptors. Sets of miRNAs were also defined as potential targets for diabetes/diabetes complication pathogenesis.

MiR-199a-5p suppresses non-small cell lung cancer via targeting MAP3K11

MicroRNAs (miRNAs) comprise a class of short, non-coding RNAs that directly target 3'UTR of mRNA, causing subsequent degradation or suppression of translation. Here, we verified that miR-199a-5p was significantly down-regulated in mouse NSCLC tissues and human patient samples. To further study the function of miR-199a-5p, lentivirus system was adopted to construct stably over-expressing miR-199a-5p A549, SPC-A1 and H1299 cell lines. Then, miR-199a-5p played a tumor suppression role via directly targeting MAP3K11 gene in non-small cell lung cancer (NSCLC). Elevated miR-199a-5p suppressed cell proliferation and arrested cell cycle in G1 phase. We found that MAP3K11 was negatively correlated with miR-199a-5p in NSCLC patient tissues and mouse xenograft tumors. Our results suggest that miR-199a-5p together with its target gene MAP3K11 is a key factor and constitutes a complicated regulation network in NSCLC.

Differential circulating and visceral fat microRNA expression of non-obese and obese subjects

BACKGROUND & AIMS

Altered microRNA (miRNA) expression is associated with the pathophysiology of obesity; however, little is known about the miRNAs commonly dysregulated in the blood and visceral fat tissue of obese patients. This study compared the circulating and visceral fat miRNA expression in subjects with and without obesity.

METHODS

For the circulating miRNA study, 20 healthy control and 30 obese subjects were recruited. For the tissue miRNA expression study, omental fat tissue was collected in ten female subjects each in the control and obese groups. MiRNA expression was measured by TaqMan low-density arrays. Metabolic risk factors were measured. Target genes for selected miRNAs were analyzed using informatics tools and a functional network map was constructed.

RESULTS

11 miRNAs were down-regulated (miR-133a, -139-5p, -15b, -26a, -301, -30b, -30c, -374, -451, -570, and -636), and one was up-regulated (miR-155) in both depots in obese subjects. These miRNAs had significant associations with BMI, waist circumference, and fat mass. Among them, miR-15b, miR-26a, miR-301, miR-30b, and miR-30c had more predicted obesity-related target genes than other miRNAs. In particular, miR-15b had numerous target genes associated with adipogenesis, mammalian target of rapamycin (mTOR) signaling, diabetes and insulin resistance, and mitochondrial function.

CONCLUSIONS

It is suggested that the miRNA alteration in the serum and visceral fat has pathophysiological implications for obesity. Our study identified dysregulated miRNAs that may be novel therapeutic targets to combat obesity.

Non-Nutritive Sweeteners and Their Implications on the Development of Metabolic Syndrome

Individuals widely use non-nutritive sweeteners (NNS) in attempts to lower their overall daily caloric intake, lose weight, and sustain a healthy diet. There are insufficient scientific data that support the safety of consuming NNS. However, recent studies have suggested that NNS consumption can induce gut microbiota dysbiosis and promote glucose intolerance in healthy individuals that may result in the development of type 2 diabetes mellitus (T2DM). This sequence of events may result in changes in the gut microbiota composition through microRNA (miRNA)-mediated changes. The mechanism(s) by which miRNAs alter gene expression of different bacterial species provides a link between the consumption of NNS and the development of metabolic changes. Another potential mechanism that connects NNS to metabolic changes is the molecular crosstalk between the insulin receptor (IR) and G protein-coupled receptors (GPCRs). Here, we aim to highlight the role of NNS in obesity and discuss IR-GPCR crosstalk and miRNA-mediated changes, in the manipulation of the gut microbiota composition and T2DM pathogenesis.

Circulating miR-143-3p inhibition protects against insulin resistance in Metabolic Syndrome via targeting of the insulin-like growth factor 2 receptor

Metabolic syndrome (MetS) is characterized by a cluster of metabolic disorders including obesity, dyslipidemia, hyperglycemia, and hypertension. Here, we report that 27 microRNAs were found to be expressed differently in serum and urine samples of MetS patients compared to control subjects on microarray analysis. Further qualitative real time- polymerase chain reaction analyses confirmed that circulating levels of miR-143-3p were significantly elevated in MetS patients compared with controls, both in serum and urine samples. After accounting for confounding factors, high levels of miR-143-3p remained an independent risk factor for insulin resistance. Inhibition of miR-143-3p expression in mice protected against development of obesity-associated insulin resistance. Furthermore, we demonstrated that insulin-like growth factor 2 receptor (IGF2R) was among the target genes of miR-143-3p by searching 3 widely used bioinformatics databases and preliminary validation. Our experiments suggest that knockdown of circulating miR-143-3p may protect against insulin resistance in the setting of MetS via targeting of IGF2R and activation of the insulin signaling pathway. Our results characterize the miR-143-3p-IGF2R pathway as a potential target for the treatment of obesity-associated insulin resistance.

miR-107 inhibits CDK6 expression, differentiation, and lipid storage in human adipocytes

MicroRNA-107 (miR-107) plays a regulatory role in obesity and insulin resistance, but the mechanisms of its function in adipocytes have not been elucidated in detail. Here we show that overexpression of miR-107 in pre- and mature human Simpson-Golabi-Behmel syndrome (SGBS) adipocytes attenuates differentiation and lipid accumulation. Our results suggest that miR-107 controls adipocyte differentiation via CDK6 and Notch signaling. CDK6 is a validated target of miR-107 and was downregulated upon miR-107 overexpression. Notch3, a signaling receptor involved in adipocyte differentiation, has been shown to decrease upon CDK6 depletion; Here Notch3 and its target Hes1 were downregulated by miR-107 overexpression. In mature adipocytes, miR-107 induces a triglyceride storage defect by impairing glucose uptake and triglyceride synthesis. To conclude, our data suggests that miR-107 has distinct functional roles in preadipocytes and mature adipocytes; Its elevated expression at these different stages of adipocytes may on one hand dampen adipogenesis, and on the other, promote ectopic fatty acid accumulation and reduced glucose tolerance.

Exercise Training-Induced Changes in MicroRNAs: Beneficial Regulatory Effects in Hypertension, Type 2 Diabetes, and Obesity

MicroRNAs are small non-coding RNAs that regulate gene expression post-transcriptionally. They are involved in the regulation of physiological processes, such as adaptation to physical exercise, and also in disease settings, such as systemic arterial hypertension (SAH), type 2 diabetes mellitus (T2D), and obesity. In SAH, microRNAs play a significant role in the regulation of key signaling pathways that lead to the hyperactivation of the renin-angiotensin-aldosterone system, endothelial dysfunction, inflammation, proliferation, and phenotypic change in smooth muscle cells, and the hyperactivation of the sympathetic nervous system. MicroRNAs are also involved in the regulation of insulin signaling and blood glucose levels in T2D, and participate in lipid metabolism, adipogenesis, and adipocyte differentiation in obesity, with specific microRNA signatures involved in the pathogenesis of each disease. Many studies report the benefits promoted by exercise training in cardiovascular diseases by reducing blood pressure, glucose levels, and improving insulin signaling and lipid metabolism. The molecular mechanisms involved, however, remain poorly understood, especially regarding the participation of microRNAs in these processes. This review aimed to highlight microRNAs already known to be associated with SAH, T2D, and obesity, as well as their possible regulation by exercise training.

MiR-31 and miR-143 affect steroid hormone synthesis and inhibit cell apoptosis in bovine granulosa cells through FSHR

The regulatory role of microRNAs (miRNAs) has been explored in ovarian cells, and the effects of miRNAs on gonadal development, apoptosis, ovulation, and steroid production have been reported. In this study, we analyzed the effects of follicle stimulating hormone (FSH) on miR-31 and miR-143 expression levels in bovine granulosa cells (GCs). Our results demonstrated that the FSH receptor (FSHR) is a common target gene of miR-31 and miR-143 in bovine GCs. We further analyzed the roles of miR-31 and miR-143 in bovine GCs by transfecting miR-31 and miR-143 mimics and inhibitors. The Western blot and RT-PCR results showed that miR-31 and miR-143 reduced the mRNA and protein expression levels of FSHR. Moreover, miR-31 overexpression decreased the secretion of progesterone (P4), and miR-143 overexpression decreased both the synthesis of P4 and the secretion of estrogen (E2). In contrast, miR-31 inhibition increased the secretion of progesterone (P4), and miR-143 inhibition increased both the synthesis of P4 and the secretion of E2. Finally, we analyzed the possible effects of miR-31 and miR-143 on bovine GC apoptosis. The results showed that transfection with miR-31 and miR-143 mimics promoted GC apoptosis and that miR-143 and miR-31 inhibition reduced the rate of apoptosis in bovine GCs. Taken together, our results indicate that miR-31 and miR-143 decrease steroid hormone synthesis and inhibit bovine GC apoptosis by targeting FSHR.

Sodium Reduction, miRNA Profiling and CVD Risk in Untreated Hypertensives: a Randomized, Double-Blind, Placebo-Controlled Trial

Sodium reduction decreases blood pressure (BP) and cardiovascular mortality. However, the underlying molecular mechanisms are not well understood. We tested the hypothesis that reduction of sodium intake would change miRNA expression in hypertensive patients, and those changes would be associated with improved cardiovascular phenotypes. A whole genome RNA sequencing was performed in paired serum samples collected at the end of usual sodium intake and reduced sodium intake periods from 10 (age 56.8 ± 8.9) untreated black male hypertensives, selected from a randomized crossover trial of sodium reduction as the discovery cohort. Validation was carried out by the PCR Serum/Plasma Focus panel profiling in paired samples in all 64 (50% males, age 50.2 ± 9.5) untreated black hypertensives from the same trial. Fifteen respondent miRNAs were identified in the discovery stage. miR-143-3p was replicated. Sodium reduction up-regulated miR-143-3p. The increase in miR-143-3p was associated with the reduction of BP and arterial stiffness and the increase in skin capillary density. In conclusion, dietary sodium reduction alters circulating miRNA expressions, and those miRNA changes are associated with reduced BP and improved arterial compliance in untreated black hypertensives, suggesting that miRNA regulation may be one of the underlying mechanisms that dietary sodium regulates cardiovascular health.

A Novel Regulator of Type II Diabetes: MicroRNA-143

MiR-143 is an miRNA with the function of specifically inhibiting the insulin-AKT pathway via the downregulation of oxysterol-binding protein-related protein 8 (ORP8), thus resulting in the inhibition of AKT phosphorylation, insulin tolerance, and final development of type II diabetes mellitus (T2DM). Aerobic exercise can prevent T2DM by downregulating miR-143. However, the underlying mechanisms for exercise-induced change of miR-143 remain unclear. In the present study, we will summarize the involvement of miR-143 in regulating the development of T2DM and the underlying mechanisms for potential diagnosis, prevention, and treatments, including exercise intervention for T2DM by targeting miR-143.

MicroRNAs as Potential Regulators of Glutathione Peroxidases Expression and Their Role in Obesity and Related Pathologies

Glutathione peroxidases (GPxs) belong to the eight-member family of phylogenetically related enzymes with different cellular localization, but distinct antioxidant function. Several GPxs are important selenoproteins. Dysregulated GPx expression is connected with severe pathologies, including obesity and diabetes. We performed a comprehensive bioinformatic analysis using the programs miRDB, miRanda, TargetScan, and Diana in the search for hypothetical microRNAs targeting 3′untranslated regions (3´UTR) of GPxs. We cross-referenced the literature for possible intersections between our results and available reports on identified microRNAs, with a special focus on the microRNAs related to oxidative stress, obesity, and related pathologies. We identified many microRNAs with an association with oxidative stress and obesity as putative regulators of GPxs. In particular, miR-185-5p was predicted by a larger number of programs to target six GPxs and thus could play the role as their master regulator. This microRNA was altered by selenium deficiency and can play a role as a feedback control of selenoproteins’ expression. Through the bioinformatics analysis we revealed the potential connection of microRNAs, GPxs, obesity, and other redox imbalance related diseases.

Noncoding RNAs Carried by Extracellular Vesicles in Endocrine Diseases

RNA molecules are essential and fine regulators of important biological processes. Their role is well documented also in the endocrine system, both in physiological and pathological conditions. Increasing interest is arising about the function and the importance of noncoding RNAs shuttled by extracellular vesicles (EVs). In fact, EV membrane protects nucleic acids from enzyme degradation. Nowadays, the research on EVs and their cargoes, as well as their biological functions, faces the lack of standardization in EV purification. Here, the main techniques for EV isolation are discussed and compared for their advantages and vulnerabilities. Despite the possible discrepancy due to methodological variability, EVs and their RNA content are reported to be key mediators of intercellular communication in pathologies of main endocrine organs, including the pancreas, thyroid, and reproductive system. In particular, the present work describes the role of RNAs contained in EVs in pathogenesis and progression of several metabolic dysfunctions, including obesity and diabetes, and their related manifestations. Their importance in the establishment and progression of thyroid autoimmunity disorders and complicated pregnancy is also discussed. Preliminary studies highlight the attractive possibility to use RNAs contained in EVs as biomarkers suggesting their exploitation for new diagnostic approaches in endocrinology.

MicroRNAs in the pathogenesis of type 2 diabetes: new research progress and future direction

miRNA is a short non-coding RNA that can influence mRNA processing at the post-transcriptional level. A large number of miRNAs have been found in virtually all species so far, and these small molecules play an important role in many different physiological processes and various pathologic conditions, such as cell metabolism, cancer, autoimmune disease, and diabetes mellitus. T2D arises from a dysregulated response to the elevated glucose level in the circulation. The prevalence of T2D has increased dramatically in all age groups, and T2D in older adults is associated with more T2D complications and higher mortality. Despite the existing findings describing the pathological mechanism, T2D pathology is more complex and the pathophysiology of the disease is still not fully elucidated. In this review, we summarize the current understanding of miRNA-mediated modulation of gene expression in T2D pathogenesis, as well as related signaling pathways, and insight into the important role of miRNA in various T2D complications. Furthermore, the potential therapeutic value of miRNA for T2D patients is also discussed in detail.

miRNAs in nutrition, obesity, and cancer: The biology of miRNAs in metabolic disorders and its relationship with cancer development

SCOPE

The scope of this review is to explain how metabolic disorders originated by a deficient nutrition can develop into a neoplastic process by the alteration of epigenetic mechanisms like miRNAs. Obesity is a proinflammatory state with a wide impact on health around the world that is associated with neoplastic diseases. Epigenetic mechanisms have a central role in the obesogenic environment, which participates on the development of comorbidities such as cancer.

METHODS AND RESULTS

We made an exhaustive review of the most recent reports about metabolic disorders with nutrition and their relationship with miRNAs, and their risk of developing into oncogenic processes. MicroRNAs (miRNAs) act as one of the major epigenetic mechanisms that can affect the metabolic reprogramming of cellular metabolism that plays an important role in the oncogenic process. There is evidence that some foods may contribute to diminishing the risk of cancer as well as epidemiological studies that support the notion that diets high in animal protein and fat promote cancer risk. Therefore, diets high in fruit and vegetables reduce the risk of cancer. One of the principal explanations is that these foods contain bioactive compounds that increase the efficacy of epigenetic mechanisms, which in turn decrease the risk of obesity and its comorbidities.

CONCLUSION

In this review, we show how miRNAs are implicated in several signaling pathways as well as illustrating some bioactive compounds that impact inflammation and cancer development.

Adipokines and free fatty acids regulate insulin sensitivity by increasing microRNA-21 expression in human mature adipocytes

Obesity is a global public health concern and may lead to a variety of complications. Previous studies have indicated that adipokines and energy‑source materials contribute to obesity and obesity‑associated insulin resistance. MicroRNAs (miRs) are endogenous 20‑ to 25‑nucleotide non‑coding RNAs associated with fat metabolism. It has been indicated that miR‑21 is associated with adipogenesis and metabolic syndrome. In the present study, the expression of miR‑21 in human mature adipocytes was analyzed using reverse transcription quantitative‑polymerase chain reaction following treatment with adipokines, including tumor necrosis factor (TNF)‑α, interleukin (IL)‑6, leptin, resistin and energy source materials, including free fatty acids (FFAs) and glucose. The current study demonstrated that the expression of miR‑21 in human mature adipocytes was upregulated following treatment with TNF‑α, IL‑6, leptin, resistin and FFAs. However, low‑ and high‑glucose did not have an effect on miR‑21 expression. These results confirmed that TNF‑α, IL‑6, leptin, resistin and FFAs may contribute to obesity and obesity‑associated insulin resistance via upregulating miR‑21 in human mature adipocytes. Therefore, miR‑21 may be a key regulatory factor of obesity and obesity‑associated insulin resistance, and represents a potential therapeutic target for the treatment of these disorders.

Comprehensive functional screening of miRNAs involved in fat cell insulin sensitivity among women

The key pathological link between obesity and type 2 diabetes is insulin resistance, but the molecular mechanisms are not entirely identified. micro-RNAs (miRNA) are dysregulated in obesity and may contribute to insulin resistance. Our objective was to detect and functionally investigate miRNAs linked to insulin sensitivity in human subcutaneous white adipose tissue (scWAT). Subjects were selected based on the insulin-stimulated lipogenesis response of subcutaneous adipocytes. Global miRNA profiling was performed in abdominal scWAT of 18 obese insulin-resistance (OIR), 21 obese insulin-sensitive (OIS), and 9 lean women. miRNAs demonstrating differential expression between OIR and OIS women were overexpressed in human in vitro-differentiated adipocytes followed by assessment of lipogenesis and identification of miRNA targets by measuring mRNA/protein expression and 3'-untranslated region analysis. Eleven miRNAs displayed differential expression between OIR and OIS states. Overexpression of miR-143-3p and miR-652-3p increased insulin-stimulated lipogenesis in human in vitro differentiated adipocytes and directly or indirectly affected several genes/proteins involved in insulin signaling at transcriptional or posttranscriptional levels. Adipose expression of miR-143-3p and miR-652-3p was positively associated with insulin-stimulated lipogenesis in scWAT independent of body mass index. In conclusion, miR-143-3p and miR-652-3p are linked to scWAT insulin resistance independent of obesity and influence insulin-stimulated lipogenesis by interacting at different steps with insulin-signaling pathways.

MicroRNAs and metabolic disorders - where are we heading?

MicroRNAs (miRNAs, miRs) are short, non-coding molecules engaged in normal functioning of eukaryotic cells, as negative regulators of gene expression. Since the first discovery of miRNA in the early 1990s, hundreds of different miRNAs and their targets have been identified. A growing number of studies have aimed to search for microRNAs which have a key role in the regulation of insulin signaling and metabolic homeostasis. Recent evidence indicates that dysregulation of miRNA expression is involved in the development of various diseases, including type 2 diabetes mellitus (T2DM), obesity and cardiovascular diseases. This review summarizes the biogenesis of miRNAs and their role in pancreatic β cell biology, insulin signaling and metabolism. We also discuss recent findings of miRNAs associated with metabolic disorders and vascular diabetic complications, their diagnosis and therapeutic value. The PubMed database and published reference lists were searched for articles published between 1990 and 2016 using the following keywords: miRNA, miRNA and pancreas; miRNA and insulin; miRNA and type 2 diabetes mellitus, miRNA and obesity, and miRNA and microvascular or macrovascular diabetic complication. This review indicates that miRNA functioning is significantly different in metabolic diseases than in the normal condition.

Changes in circulating microRNA levels can be identified as early as day 8 of pregnancy in cattle

Poor reproductive performance remains a major issue in the dairy industry, with low conception rates having a significant impact on milk production through extended calving intervals. A major limiting factor is the lack of reliable methods for early pregnancy diagnosis. Identification of animals within a herd that fail to conceive within 3 weeks after insemination would allow early re-insemination and shorten calving intervals. In a previous study, we found an increase in plasma miR-26a levels in Day 16-pregnant relative to non-pregnant heifers, however changes in miRNA levels that early during pregnancy were very small which likely prevented the identification of robust biomarkers. In this study, we extended our analyses to a wider interval during pregnancy (Days 8 to 60, n = 11 heifers) with the rationale that this may facilitate the identification of additional early pregnancy miRNA biomarkers. Using small RNA sequencing we identified a total of 77 miRNAs that were differentially expressed on Day 60 relative to Day 0 of pregnancy. We selected 14 miRNAs for validation by RT-qPCR and confirmed significant differences in the expression of let-7f, let-7c, miR-30c, miR-101, miR-26a, miR-205 and miR-143 between Days 0 and 60. RT-qPCR profiling throughout Days 0, 8, 16 and 60 of pregnancy showed a distinct increase in circulating levels of miR-26a (3.1-fold, P = 0.046) as early as Day 8 of pregnancy. In summary, in contrast to earlier stages of pregnancy (≤ Day 24), marked differences in the levels of multiple miRNAs can be detected in circulation by Day 60 in cattle. Retrospective analyses showed miR-26a levels to be increased in circulation as early as Day 8, sooner than previously reported in any species, suggesting a biological role for this miRNA in the very early events of pregnancy.

Inflammation Related MicroRNAs Are Modulated in Total Plasma and in Extracellular Vesicles from Rats with Chronic Ingestion of Sucrose

Circulating microRNAs (miRNAs) and the functional implications of miRNAs contained in extracellular vesicles (EVs) have gained attention in the last decade. Little is known about the regulation of the abundance of plasma miRNAs in response to chronic ingestion of carbohydrates. Therefore, we explored the circulating levels of miR-21, miR-146a, miR-155, and miR-223 in rats consuming sucrose in drinking water. Weanling Wistar rats were 25 weeks with 30% sucrose in drinking water, and miRNAs expression was determined in total plasma and in microvesicles, by RT-qPCR with TaqMan probe based assays for miR-21, miR-146a, miR-155, and miR-223, using cel-miR-39 (as spike in control and reference). Endotoxemia was also measured. Sucrose-fed animals showed higher body weight and retroperitoneal adipose tissue as well as higher glucose and triglyceride plasma levels than controls. Plasma endotoxin levels were low and not different among groups. Plasma miR-21 and miR-223 were higher in the sucrose group (p < 0.05), whereas miR-155 tended to be lower (p = 0.0661), and miR-146a did not show significant differences. In the plasma EVs the same trend was found except for miR-146a that showed significantly higher levels (p < 0.05). Overall, our results show that high carbohydrate ingestion modulates circulating miRNAs levels related to an inflammatory response.

Maternal high-calorie diet is associated with altered hepatic microRNA expression and impaired metabolic health in offspring at weaning age

High-calorie diet (HCD) feeding in mice predisposes offspring for impaired glucose homeostasis and obesity. However, the mechanisms underlying these detrimental effects of maternal nutrition, especially during early life of offspring, are incompletely understood. MicroRNAs (miRNAs) are small non-coding RNAs that can regulate target gene expression. Here we hypothesized that impaired metabolic health in offspring from HCD-fed dams at weaning is associated with dysregulated expression of hepatic miRNAs. Dams were fed a chow diet (CD; 11.4 % kcal fat, 62.8 % from carbohydrate, 25.8 % from protein) or HCD (58 % kcal from fat; 25.6 % from carbohydrate, 16.4 % from protein) during gestation and lactation, and metabolic health was assessed in male offspring at weaning. Hepatic levels of miRNAs and target genes were investigated in offspring from CD- or HCD-fed dams using gene and protein expression. Maternal HCD feeding impaired metabolic health in offspring compared to offspring from CD-fed dams. Microarray analysis indicated that expressions of miR-615-5p, miR-3079-5p, miR-124*, and miR-101b* were downregulated, whereas miR-143* was upregulated, in livers from offspring from HCD-fed dams. Our functional enrichment analysis indicated that the target genes of these differentially expressed miRNAs, including tumor necrosis factor-α (TNF-α) and mitogen-activated protein kinase 1 (MAPK1), were mapped to inflammatory pathways. Finally, we verified that both mRNA and protein levels of the pro-inflammatory modulators TNF-α and MAPK1 were significantly increased in livers of offspring from HCD-fed dams at weaning. Maternal HCD feeding predisposes offspring to a higher body weight and impaired glucose metabolism at weaning. To the best of knowledge, our study is the first to show that maternal HCD consumption impairs metabolic health, modulates hepatic miRNA expression, and increases markers of hepatic inflammation in offspring as early as at weaning age.

Circulating MicroRNA Responses between 'High' and 'Low' Responders to a 16-Wk Diet and Exercise Weight Loss Intervention

Background

Interactions between diet, physical activity and genetic predisposition contribute to variable body mass changes observed in response to weight loss interventions. Circulating microRNAs (c-miRNAs) may act as ‘biomarkers’ that are associated with the rate of change in weight loss, and/or play a role in regulating the biological variation, in response to energy restriction.

Objective

To quantify targeted c-miRNAs with putative roles in energy metabolism and exercise adaptations following a 16 wk diet and exercise intervention in individuals with large (high responders; HiRes) versus small (low responders; LoRes) losses in body mass.

Methods

From 89 male and female overweight/obese participants who completed the intervention (energy restriction from diet, 250 kcal/d, and exercise, 250 kcal/d), subgroups of HiRes (>10% body mass loss, n = 22) and LoRes (<5% body mass loss, n = 18) were identified. From resting plasma samples collected after an overnight fast pre and post intervention, RNA was extracted, quantified and reverse transcribed. Thirteen c-miRNA selected a priori were analysed using a customised 96-well miScript miRNA PCR Array.

Results

Loss of body mass (-11.0 ± 2.3 kg vs. -3.0 ± 1.3 kg; P<0.01) and fat mass (-11.1 ± 2.6 kg vs. -3.9 ± 1.6 kg; P<0.01) was greater for HiRes than LoRes (P<0.001). Expression of c-miR-935 was higher in LoRes compared to HiRes pre- (~47%; P = 0.025) and post- (~100%; P<0.01) intervention and was the only c-miRNA differentially expressed at baseline between groups. The abundance of c-miR-221-3p and -223-3p increased pre- to post-intervention in both groups (~57–69% and ~25–90%, P<0.05). There was a post-intervention increase in c-miR-140 only in LoRes compared to HiRes (~23%, P = 0.016).

Conclusion

The differential expression and responses of selected c-miRNAs in overweight/obese individuals to an exercise and diet intervention suggests a putative role for these ‘biomarkers’ in the prediction or detection of individual variability to weight loss interventions.

Neuroendocrinological and Epigenetic Mechanisms Subserving Autonomic Imbalance and HPA Dysfunction in the Metabolic Syndrome

Impact of environmental stress upon pathophysiology of the metabolic syndrome (MetS) has been substantiated by epidemiological, psychophysiological, and endocrinological studies. This review discusses recent advances in the understanding of causative roles of nutritional factors, sympathomedullo-adrenal (SMA) and hypothalamic-pituitary adrenocortical (HPA) axes, and adipose tissue chronic low-grade inflammation processes in MetS. Disturbances in the neuroendocrine systems for leptin, melanocortin, and neuropeptide Y (NPY)/agouti-related protein systems have been found resulting directly in MetS-like conditions. The review identifies candidate risk genes from factors shown critical for the functioning of each of these neuroendocrine signaling cascades. In its meta-analytic part, recent studies in epigenetic modification (histone methylation, acetylation, phosphorylation, ubiquitination) and posttranscriptional gene regulation by microRNAs are evaluated. Several studies suggest modification mechanisms of early life stress (ELS) and diet-induced obesity (DIO) programming in the hypothalamic regions with populations of POMC-expressing neurons. Epigenetic modifications were found in cortisol (here HSD11B1 expression), melanocortin, leptin, NPY, and adiponectin genes. With respect to adiposity genes, epigenetic modifications were documented for fat mass gene cluster APOA1/C3/A4/A5, and the lipolysis gene LIPE. With regard to inflammatory, immune and subcellular metabolism, PPARG, NKBF1, TNFA, TCF7C2, and those genes expressing cytochrome P450 family enzymes involved in steroidogenesis and in hepatic lipoproteins were documented for epigenetic modifications.

MicroRNA-223 Is Upregulated in Active Tuberculosis Patients and Inhibits Apoptosis of Macrophages by Targeting FOXO3

BACKGROUND

Macrophage apoptosis is a host innate defense mechanism against tuberculosis (TB).

AIM

In this study, we aimed to investigate the role of microRNA-223 (miR-223) in macrophage apoptosis of TB.

METHODS

We analyzed apoptosis in peripheral blood macrophages of active TB patients, infected human macrophages (TDMs and MDMs) with the Mycobacterium tuberculosis (Mtb) strain H37Rv, and observed the expression of miR-223 to investigate the relationship between miR-223 and macrophage apoptosis induced by Mtb.

RESULTS

The apoptosis rate of peripheral blood macrophages decreased in active TB patients compared with healthy controls, and miR-223 expression increased significantly in macrophages after H37Rv infection. Transfection of human macrophages (TDMs and MDMs) with miR-223 inhibited macrophage apoptosis. We also demonstrated that miR-223 directly suppressed forkhead box O3 (FOXO3), and FOXO3 played a critical role as a mediator of the biological effects of miR-223 in macrophage apoptosis. The overexpression of FOXO3 remarkably reversed the apoptosis inhibitory effect of miR-223.

CONCLUSION

Our data provide new clues for the essential role of miR-223 in the regulation of anti-Mtb-directed immune responses, which relies on the regulation of FOXO3 expression.

Circulating microRNAs in obese and lean heart failure patients: A case-control study with computational target prediction analysis

AIMS

MicroRNAs (miRs) regulate processes involved in both cardiac remodeling and obesity. We investigated if the expression of selected miRs in patients with heart failure (HF) is influenced by the presence of obesity.

METHODS

In this case-control study, we compared plasma levels of miR-21, -130b, -221, -423-5p, and the -221/-130b ratio in 57 age- and gender-matched subjects: 40 HF patients (20 obese HF and 20 lean HF) and 17 lean healthy controls. Body composition was estimated by bioelectrical impedance analysis. MiRs were measured by quantitative reverse transcription-PCR. Bioinformatics analysis was performed based on miRs findings to predict their putative targets and investigate their biological function.

RESULTS

HF was associated with increased miR-423-5p levels in both lean and obese patients (P<0.05 vs. controls) without differences between HF groups. MiR-130b levels were reduced in obese HF patients compared with HF lean (P=0.036) and controls (P=0.025). MiR-221 levels were non-significantly increased in obese HF patients. MiR-21 levels were not different among the groups. MiR-221/-130b ratio was increased in obese HF patients, and was positively associated with body fat percentage (r=0.43; P=0.002), body mass index (r=0.44; P=0.002), and waist circumference (r=0.40; P=0.020). Computational prediction of target genes followed by functional enrichment analysis indicated a relevant role of miR-130b and miR-221 in modulating the expression of genes associated to cardiovascular and endocrine diseases, and suggested their influence in important signaling mechanisms and in numerous processes related to the circulatory and endocrine systems.

CONCLUSIONS

In HF patients, the presence of obesity is associated with a differential expression of selected miRs and the miR-221/-130b ratio had significant correlations with adiposity parameters. Computational target prediction analysis identified several interrelated pathways targeted by miR-130b and miR-221 with a known relationship with endocrine and cardiovascular diseases, representing potential mechanisms to be further validated.

Differential expression of miR-499 and validation of predicted target genes in the testicular tissue of swine at different developmental stages

microRNAs (miRNAs) represent a newly identified class of nonprotein-coding ∼ 22 nt small RNA that plays important roles in multiple biological processes by degrading targeted mRNA or repressing mRNA translation. This study observed the morphology of swine testicular tissue at different developmental stages (including 1-day old, 1-7 month old) by Hematoxylin-eosin staining. We also examined the expression of miR-499 and its target genes (CYLC1, DMRT1, QKI, XRN2, ZNF313) in samples of tissue slices using quantitative reverse-transcription polymerase chain reaction, which showed that miR-499 had a significant negative correlation with QKI gene. Then, the proteins of QKI gene expression were determined by western blot, which were consistent with results of quantitative polymerase chain reaction (qPCR) detection. Therefore, the luciferase reporter gene system was used to verify correlation between miR-499 and QKI gene. Activity of luciferase was significantly lower in miR-499 co-transfected with pmiR-RB-REPORT-QKI-WT group than the miR-499 co-transfected with pmiR-RB-REPORT-QKI-mut/si groups, indicating that target sequence of miR-499 existed in 3'UTR of QKI gene. Furthermore, the expressions of miR-499 and QKI were detected in testicular cells that were transfected with miR-499, miR-499 negative control and untreated. The results showed that the diameter of convoluted seminiferous tubule growth increased with age. Significantly different expressions of miR-499 and its target genes were found in swine testicular tissue at different developmental stages (p<0.05), overexpressing miR-499 analysis, suggesting that miR-499 was negatively correlated to the expression of QKI (p<0.05). In conclusion, QKI is a target gene of miR-499.