MicroRNAs in obesity-associated disorders

Regulatory Roles of MicroRNAs in the Pathogenesis of Metabolic Syndrome

Metabolic syndrome refers to a group of several disease conditions together with high glucose triglyceride levels, high blood pressure, lower high-density lipoprotein level, and large waist circumference. About 400 million people worldwide, one-third of the Euro-American population and 27% Chinese population over age 50 have it. microRNAs, an abundant novel class of endogenous small, non-coding RNAs in eukaryotic cells, act as negative controllers of gene expression by promoting either degradation/translational repression of target messenger RNA. More than 2000 microRNAs in the human genome have been identified and they are implicated in various biological & pathophysiological processes, including glucose homeostasis, inflammatory response, and angiogenesis. Destruction of microRNAs has a crucial role in the pathogenesis of obesity, cardiovascular disease, and diabetes. Recently the discovery of circulating microRNAs in human serum may help to promote metabolic crosstalk between organs and serves as a novel approach for the identification of various diseases, like Type 2 diabetes & atherosclerosis. In this review, we will discuss the most recent and up-to-date research on the pathophysiology and histopathology of metabolic syndrome besides their historical background and epidemiological highlight. As well as search the methodologies employed in this field of research and the potential role of microRNAs as novel biomarkers and therapeutic targets for metabolic syndrome in the human body. Furthermore, the significance of microRNAs in promising strategies, like stem cell therapy, which holds enormous promise for regenerative medicine in the treatment of metabolic disorders will also be discussed.

Molecular and Cellular Mechanisms of Intramuscular Fat Development and Growth in Cattle

Intramuscular fat, also referred to as marbling fat, is the white fat deposited within skeletal muscle tissue. The content of intramuscular fat in the skeletal muscle, particularly the longissimus dorsi muscle, of cattle is a critical determinant of beef quality and value. In this review, we summarize the process of intramuscular fat development and growth, the factors that affect this process, and the molecular and epigenetic mechanisms that mediate this process in cattle. Compared to other species, cattle have a remarkable ability to accumulate intramuscular fat, partly attributed to the abundance of sources of fatty acids for synthesizing triglycerides. Compared to other adipose depots such as subcutaneous fat, intramuscular fat develops later and grows more slowly. The commitment and differentiation of adipose precursor cells into adipocytes as well as the maturation of adipocytes are crucial steps in intramuscular fat development and growth in cattle. Each of these steps is controlled by various factors, underscoring the complexity of the regulatory network governing adipogenesis in the skeletal muscle. These factors include genetics, epigenetics, nutrition (including maternal nutrition), rumen microbiome, vitamins, hormones, weaning age, slaughter age, slaughter weight, and stress. Many of these factors seem to affect intramuscular fat deposition through the transcriptional or epigenetic regulation of genes directly involved in the development and growth of intramuscular fat. A better understanding of the molecular and cellular mechanisms by which intramuscular fat develops and grows in cattle will help us develop more effective strategies to optimize intramuscular fat deposition in cattle, thereby maximizing the quality and value of beef meat.

miR-665-Mediated Regulation of AHCYL2 and BVES Genes in Recurrent Implantation Failure

The primary goal of this investigation was to identify mRNA targets affected by dysregulated miRNAs in RIF. This was accomplished by comprehensively analyzing mRNA and miRNA expression profiles in two groups: female subjects with normal reproductive function (control, n = 5) and female subjects experiencing recurrent implantation failure (RIF, n = 5). We conducted transcriptome sequencing and small RNA sequencing on endometrial tissue samples from these cohorts. Subsequently, we validated a selection of intriguing findings using real-time PCR with samples from the same cohort. In total, our analysis revealed that 929 mRNAs exhibited differential expression patterns between the control and RIF patient groups. Notably, our investigation confirmed the significant involvement of dysregulated genes in the context of RIF. Furthermore, we uncovered promising correlation patterns within these mRNA/miRNA pairs. Functional categorization of these miRNA/mRNA pairs highlighted that the differentially expressed genes were predominantly associated with processes such as angiogenesis and cell adhesion. We identified new target genes that are regulated by miR-665, including Blood Vessel Epicardial Substance (BVES) and Adenosylhomocysteinase like 2 (AHCYL2). Our findings suggest that abnormal regulation of genes involved in angiogenesis and cell adhesion, including BVES and AHCYL2, contributes to the endometrial dysfunction observed in women with recurrent implantation failure (RIF) compared to healthy women.

The Regulatory Role of MicroRNAs in Obesity and Obesity-Derived Ailments

Obesity is a condition that is characterized by the presence of excessive adipose tissue in the body. Obesity has become one of the main health concerns worldwide since it can lead to other chronic ailments, such as type 2 diabetes or fatty liver disease, and it could be an aggravating factor in infections. MicroRNAs (miRNAs) are small, non-coding RNA molecules that regulate gene expression and can play an important role in controlling crucial biological processes involved in the onset of obesity, such as lipogenesis, adipogenesis, lipid metabolism, or the regulation of cytokines and chemokines. Moreover, chemical compounds present in food or food packaging can alter miRNA expression and regulate the aforementioned biological mechanisms related to diabetes onset and progression. Furthermore, therapies, such as bariatric surgery and aerobic exercise training, can also influence the expression profile of miRNAs in obesity. Therefore, the present review provides insight into the current research on the role of miRNAs in obesity and obesity-derived ailments, intending to develop novel therapies to effectively manage these disorders.

Deciphering Obesity-Related Gene Clusters Unearths SOCS3 Immune Infiltrates and 5mC/m6A Modifiers in Ossification of Ligamentum Flavum Pathogenesis

BACKGROUND

Ossification of ligamentum flavum (OLF) is an insidious and debilitating heterotopic ossifying disease with etiological heterogeneity and undefined pathogenesis. Obese individuals predispose to OLF, whereas the underlying connections between obesity phenotype and OLF pathomechanism are not fully understood. Therefore, this study aims to explore distinct obesity-related genes and their functional signatures in OLF.

METHODS

The transcriptome sequencing data related to OLF were downloaded from the GSE106253 in the Gene Expression Omnibus (GEO) database. The obesity-related differentially expressed genes (ORDEGs) in OLF were screened, and functional and pathway enrichment analysis were applied for these genes. Furthermore, protein-protein interactions (PPI), module analysis, transcription factor enrichment analysis (TFEA), and experiment validation were used to identify hub ORDEGs. The immune infiltration landscape in OLF was depicted, and correlation analysis between core gene SOCS3 and OLF-related infiltrating immune cells (OIICs) as well as 5mC/m6A modifiers in OLF was constructed.

RESULTS

Ninety-nine ORDEGs were preliminarily identified, and functional annotations showed these genes were mainly involved in metabolism, inflammation, and immune-related biological functions and pathways. Integrative bioinformatic algorithms determined a crucial gene cluster associated with inflammatory/immune responses, such as TNF signaling pathway, JAK-STAT signaling pathway, and regulation of interferon-gamma-mediated signaling. Eight hub ORDEGs were validated, including 6 down-regulated genes (SOCS3, PPARG, ICAM-1, CCL2, MYC, and NT5E) and 2 up-regulated genes (PTGS2 and VEGFA). Furthermore, 14 differential OIICs were identified by ssGSEA and xCell, and SOCS3 was overlapped to be the core gene, which was associated with multiple immune infiltrates (dendritic cells, macrophage, and T cells) and six m6A modifiers as well as four 5mC regulators in OLF. Reduced SOCS3 and FTO expression and up-regulated DNMT1 level in OLF were validated by Western blotting.

CONCLUSION

This study deciphered immune/inflammatory signatures of obesity-related gene clusters for the first time, and defined SOCS3 as one core gene. The crosstalk between 5mC/m6A methylation may be a key mediator of SOCS3 expression and immune infiltration. These findings will provide more insights into molecular mechanisms and therapeutic targets of obesity-related OLF.

MicroRNAs in Obesity-Associated Disorders: The Role of Exercise Training

Obesity is a worldwide epidemic affecting over 13% of the adult population and is defined by an excess of body fat that predisposes comorbidities. It is considered a multifactorial disease in which environmental and genetic factors interact, and it is a risk marker for cardiovascular disease. Lifestyle modifications remain the mainstay of treatment for obesity based on adequate diet and physical exercise. In addition, obesity is related to cardiovascular and skeletal muscle disorders, such as cardiac hypertrophy, microvascular rarefaction, and skeletal muscle atrophy. The discovery of obesity-involved molecular pathways is an important step to improve both the prevention and management of this disease. MicroRNAs (miRNAs) are a class of gene regulators which bind most commonly, but not exclusively, to the 3'-untranslated regions of messenger RNAs of protein-coding genes and negatively regulate their expression. Considerable effort has been made to identify miRNAs and target genes that predispose to obesity. Besides their intracellular function, recent studies have demonstrated that miRNAs can be exported or released by cells and circulate within the blood in a remarkably stable form. The discovery of circulating miRNAs opens up intriguing possibilities for the use of circulating miRNA patterns as biomarkers for obesity and cardiovascular diseases. The aim of this review is to provide an overview of the recent discoveries of the role played by miRNAs in the obese phenotype and associated comorbidities. Furthermore, we will discuss the role of exercise training on regulating miRNAs, indicating the mechanisms related to these alterations.

Electroacupuncture altered expression of microRNAs in Stat5 knockout obese mice

BACKGROUND

Increasing evidence shows that miRNAs contribute to the establishment and development of obesity by affecting many biological and pathological processes, such as adipocyte differentiation, hepatic lipid metabolism, insulin resistance, and neurological regulation of obesity. As a clinical intervention approach, acupuncture has been shown to be effective in the treatment of obesity and other metabolic diseases. Our previous whole genome study in central nervous system (CNS)-specific Stat5 knockout (NKO) obese mice found that electroacupuncture (EA) could reduce body weight and promote white browning.

OBJECTIVE

To clarify the effect of EA on miRNAs and understand how it regulates gene expression.

METHODS

Twelve-week-old male Stat5NKO mice with body weight 20% greater than that of Stat5fl/fl (control) mice were divided into a Stat5NKO (model) group and EA-treated Stat5NKO + EA group. A cohort of Stat5fl/fl mice of the same age were included as the control group. EA was administered under isoflurane anesthesia at unilateral ST36 and ST44 daily (left and right sides were treated every other day), 6 times per week for a total of 4 weeks. The miRNA profile was generated and miRNA regulatory networks were analyzed in the Stat5 nestin-cre mice before and after EA treatment. Autophagy-related proteins in adipocytes were detected after over-expression of miR27a.

RESULTS

EA altered abnormal miRNA expression, including miRNA27a expression, and reduced the autophagy-related proteins ATG5 and ATG12.

CONCLUSION

We found that EA could regulate miRNA27a-mediated autophagy-related proteins and promote white fat browning, which may contribute to weight loss. To our knowledge, this is the first report of miRNAs potentially driving the effect of EA on white fat browning through the autophagy process.

Association of microRNAs With Embryo Development and Fertilization in Women Undergoing Subfertility Treatments: A Pilot Study

Objective: Small non-coding RNAs, known as microRNAs (miRNAs), have emerging regulatory functions within the ovary that have been related to fertility. This study was undertaken to determine if circulating miRNAs reflect the changes associated with the parameters of embryo development and fertilization.

Methods: In this cross-sectional pilot study. Plasma miRNAs were collected from 48 sequentially presenting women in the follicular phase prior to commencing in vitro fertilization (IVF). Circulating miRNAs were measured using locked nucleic acid (LNA)-based quantitative PCR (qPCR), while an updated miRNA data set was used to determine their level of expression.

Results: Body mass index and weight were associated with the miRNAs let7b-3p and miR-375, respectively (p < 0.05), with the same relationship being found between endometrium thickness at oocyte retrieval and miR-885-5p and miR-34a-5p (p < 0.05). In contrast, miR-1260a was found to be inversely associated with anti-Mullerian hormone (AMH; p = 0.007), while miR-365a-3p, miR122-5p, and miR-34a-5p correlated with embryo fertilization rates (p < 0.05). However, when omitting cases of male infertility (n = 15), miR122-5p remained significant (p < 0.05), while miR-365a-3p and miR-34a-5p no longer differed; interestingly, however, miR1260a and mir93.3p became significant (p = 0.0087/0.02, respectively). Furthermore, age was negatively associated with miR-335-3p, miR-28-5p, miR-155-5p, miR-501-3p, and miR-497-5p (p < 0.05). Live birth rate was negatively associated with miR-335-3p, miR-100-5p, miR-497-5p, let-7d, and miR-574-3p (p < 0.05), but these were not significant when age was accounted for.However, with the exclusion of male factor infertility, all those miRNAs were no longer significant, though miR.150.5p emerged as significant (p = 0.042). A beta-regression model identified miR-1260a, miR-486-5p, and miR-132-3p (p < 0.03, p = 0.0003, p < 0.00001, respectively) as the most predictive for fertilization rate. Notably, changes in detectable miRNAs were not linked to cleavage rate, top quality embryos (G3D3), and blastocyst or antral follicle count. An ingenuity pathway analysis showed that miRNAs associated with age were also associated with the variables found in reproductive system diseases.

Conclusion: Plasma miRNAs prior to the IVF cycle were associated with differing demographic and IVF parameters, including age, and may be predictive biomarkers of fertilization rate.

Integrated Analysis of mRNA-seq and miRNA-seq to Identify c-MYC, YAP1 and miR-3960 as Major Players in the Anticancer Effects of Caffeic Acid Phenethyl Ester in Human Small Cell Lung Cancer Cell Line

BACKGROUND

Caffeic Acid Phenethyl Ester (CAPE), an active extract of propolis, has recently been reported to have broad applications in various cancers. However, the effects of CAPE on Small Cell Lung Cancer (SCLC) are largely unknown. Therefore, the aim of this study was to determine the anti-proliferative effect of CAPE and explore the underlying molecular mechanisms in SCLC cells using high-throughput sequencing and bioinformatics analysis.

METHODS

Small-cell lung cancer H446 cells were treated with CAPE, and cell proliferation and apoptosis were then assessed. Additionally, the regulation mediated by miR-3960 after CAPE treatment was explored and the altered signaling pathways were predicted in a bioinformatics analysis.

RESULTS

CAPE significantly inhibited cell proliferation and induced apoptosis. CAPE decreased the expression of Yes-Associated Protein 1 (YAP1) and cellular myelocytomatosis oncogene (c-MYC) protein. Moreover, the upregulation of miR-3960 by CAPE contributed to CAPE-induced apoptosis. The knockdown of miR-3960 decreased the CAPE-induced apoptosis.

CONCLUSION

We demonstrated the anti-cancer effect of CAPE in human SCLC cells and studied the mechanism by acquiring a comprehensive transcriptome profile of CAPE-treated cells.

MicroRNA-10a-3p Improves Cartilage Degeneration by Regulating CH25H-CYP7B1-RORα Mediated Cholesterol Metabolism in Knee Osteoarthritis Rats

Osteoarthritis (OA) is a worldwide degenerative joint disease that seriously impaired the quality of life of patients. OA has been established as a disease with metabolic disorder. Cholesterol 25-hydroxylase (CH25H) was proved to play a key role in cartilage cholesterol metabolism. However, the biological function and mechanism of CH25H in OA remains further investigation. Growing researches have proved the vital roles of miRNAs in OA progression. In this study, we screened out miR-10a-3p through high-throughput miRNA sequencing which may bind to CH25H. Molecular mechanism investigation indicated that miR-10a-3p is an upstream target of CH25H. Functional exploration revealed miR-10a-3p suppressed the inflammatory responses, cholesterol metabolism and extracellular matrix (ECM) degradation in primary chondrocytes. Moreover, rescue assays implied that miR-10a-3p reversed CH25H plasmids induced inflammatory cytokine production and ECM degradation. Furthermore, the OA rat model was established to explore the function of miR-10a-3p in vivo. The results showed that miR-10a-3p can recover the OA features through targeting CH25H/CYP7B1/RORα axis. In conclusion, these findings implied a crucial role of miR-10a-3p/CH25H/CYP7B1/RORα axis in OA, which may provide a promising therapeutic strategy for OA.

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.

Peripheral Blood miRome Identified miR-155 as Potential Biomarker of MetS and Cardiometabolic Risk in Obese Patients

This study explored circulating miRNAs and target genes associated with metabolic syndrome (MetS) and cardiometabolic risk in obese patients. Small-RNA sequencing was used to assess the peripheral blood miRNome of 12 obese subjects (6 MetS and 6 non-MetS). Differentially expressed miRNAs and target genes were further analyzed by qPCR in a larger sample of obese patients (48 MetS and 32 non-MetS). miRNA:mRNA interactions were studied using in silico tools. miRNome analysis identified 10 downregulated miRNAs in MetS compared to non-Met patients (p < 0.05). In silico studies revealed three miRNAs (miR-155, miR-181a, and let-7a) and their predictive targets (CCAAT/enhancer-binding protein beta-CEBPB, KRAS proto-oncogene, GTPase-KRAS and suppressor of cytokine signaling 1-SOCS1) with a potential role in the insulin receptor signaling pathway. miR-155 expression was reduced and CEBPB mRNA levels were increased in MetS patients (p < 0.05), and these effects were correlated with the number of MetS diagnostic criteria (p < 0.05). Increased HOMA-IR (>7.6) was associated with low miR-155 levels, high CEBPB expression, and serum hsCRP (p < 0.05). miR-155 was negatively correlated with CEBPB, HOMA-IR, and plasma fibrinogen, and positively correlated with serum adiponectin (p < 0.05). Downregulation of circulating miR-155 is associated with insulin resistance, poor glycemic control, and increased MetS-related cardiometabolic risk, and these effects are potentially mediated by interaction with CEBPB.

Dietary Lactate Supplementation Protects against Obesity by Promoting Adipose Browning in Mice

Yogurt has been widely used in weight-loss foods to prevent obesity, but its molecular nature remains unclear. Lactate is a major ingredient of yogurt, while its cognate cell surface receptor GPR81 is highly expressed in adipose tissues in mammals. Here we hypothesized that dietary lactate supplementation might activate GPR81 to promote adipose browning. Studying mouse models, we observed that GPR81 was substantially lowered in adipose tissue of obese mice compared with that for lean ones, whereas its expression was markedly up-regulated by a β3-adrenergic receptor (β3-AR) agonist. The deficiency of GPR81 greatly attenuated experimental adipose browning and thermogenesis. Importantly, oral administration of lactate effectively induced adipose browning, enhanced thermogenesis, improved dyslipidemia, and protected mice against high-fat-diet-induced obesity. Mechanistically, p38 mitogen-activated protein kinase might serve as a key downstream effect or of GPR81. Collectively, our findings revealed a critical role of GPR81 in adipose browning and provided a new insight into obesity management by modulating lactate-GPR81 signaling axis.

Metabolic and energetic benefits of microRNA-22 inhibition

INTRODUCTION

We previously demonstrated in primary cultures of human subcutaneous adipocytes and in a mouse model of diet-induced obesity that specific microRNA-22-3p antagomirs produce a significant reduction of fat mass and an improvement of several metabolic parameters. These effects are related to the activation of target genes such as KDM3A, KDM6B, PPARA, PPARGC1B and SIRT1 involved in lipid catabolism, thermogenesis, insulin sensitivity and glucose homeostasis.

RESEARCH DESIGN AND METHODS

We now report a dedicated study exploring over the course of 3 months the metabolic and energetic effects of subcutaneous administration of our first miR-22-3p antagomir drug candidate (APT-110) in adult C57BL/6 male mice. Body composition, various blood parameters and energy expenditure were measured at several timepoints between week 12 and week 27 of age.

RESULTS

Weekly subcutaneous injections of APT-110 for 12 weeks produced a sustained increase of energy expenditure as early as day 11 of treatment, a significant fat mass reduction, but no change of appetite nor physical activity. Insulin sensitivity as well as circulating glucose, cholesterol and leptin were improved. There was a dramatic reduction of liver steatosis after 3 months of active treatment. RNA sequencing revealed an activation of lipid metabolism pathways in a tissue-specific manner.

CONCLUSIONS

These original findings suggest that microRNA-22-3p inhibition could lead to a potent treatment of fat accumulation, insulin resistance, and related complex metabolic disorders such as obesity, type 2 diabetes mellitus and non-alcoholic fatty liver disease.

Adipose Tissue Fibrosis: Mechanisms, Models, and Importance

Increases in adipocyte volume and tissue mass due to obesity can result in inflammation, further dysregulation in adipose tissue function, and eventually adipose tissue fibrosis. Like other fibrotic diseases, adipose tissue fibrosis is the accumulation and increased production of extracellular matrix (ECM) proteins. Adipose tissue fibrosis has been linked to decreased insulin sensitivity, poor bariatric surgery outcomes, and difficulty in weight loss. With the rising rates of obesity, it is important to create accurate models for adipose tissue fibrosis to gain mechanistic insights and develop targeted treatments. This article discusses recent research in modeling adipose tissue fibrosis using in vivo and in vitro (2D and 3D) methods with considerations for biomaterial selections. Additionally, this article outlines the importance of adipose tissue in treating other fibrotic diseases and methods used to detect and characterize adipose tissue fibrosis.

Levels of Circulating miR-122 are Associated with Weight Loss and Metabolic Syndrome

OBJECTIVE

This study investigated whether the levels of specific serum microRNAs (miRNAs) were altered following diet-induced weight loss and whether the serum miRNAs differed in the presence of the metabolic syndrome.

METHODS

The study was a weight loss intervention trial with a prescribed energy deficit of approximately 500 kcal/d. Levels of 22 miRNAs were determined in serum samples from 85 participants with overweight or obesity. miRNAs were analyzed using TaqMan Array miRNA Cards and normalized to the geometric mean of spiked-in ath-miR-159a and U6 small nuclear RNA using the ΔC_T method.

RESULTS

The average weight loss was 5.7 kg (P < 0.001). miR-122-5p (-0.18 ± 0.06 log fold relative to initial, P < 0.01) and miR-193a-5p (-0.12 ± 0.04, P < 0.01) levels decreased in response to weight loss. miR-126a-3p (0.11 ± 0.04, P = 0.01) and miR-222-3p (1.51 ± 0.12, P < 0.001) levels increased. Furthermore, a higher level of miR-122-5p was observed at baseline in participants with the metabolic syndrome compared with participants without (0.28 ± 0.08, P < 0.01).

CONCLUSIONS

Changes in circulating miR-122-5p, miR-126a-3p, miR-193a-5p, and miR-222-3p in response to diet-induced weight loss are demonstrated. Furthermore, assessment of miR-122-5p could be an indicator of an adverse metabolic health status independent of obesity.

Metabolic Benefits of MicroRNA-22 Inhibition

Diabesity is a growing pandemic with substantial health and financial consequences. We are developing microRNA (miRNA)-based drug candidates that transform fat storing adipocytes into fat burning adipocytes (browning effect) to treat metabolic diseases characterized by lipotoxicity. Through phenotypic screening in primary cultures of human subcutaneous adipocytes, we discovered that inhibition of miRNA-22-3p by several complementary antagomirs resulted in increased lipid oxidation, mitochondrial activity, and energy expenditure (EE). These effects may be mediated through activation of target genes like KDM3A, KDM6B, PPARA, PPARGC1B, and SIRT1 involved in lipid catabolism, thermogenesis, and glucose homeostasis. In the model of Diet-Induced Obesity in mice of various ages, weekly subcutaneous injections of various miRNA-22-3p antagomirs produced a significant fat mass reduction, but no change of appetite or body temperature. Insulin sensitivity, as well as circulating glucose and cholesterol levels, was also improved. These original findings suggest that miRNA-22-3p inhibition could become a potent treatment of human obesity and type 2 diabetes mellitus, the so-called diabesity characterized by lipotoxicity and insulin resistance.

Circulating microRNAs in human obesity: a systematic review

Context: Differential expression profiles of microRNAs have been reported in human obesity suggesting a miRNAs role in the development of obesity and associated disorders. Objective: To review circulating microRNAs (c-miRNAs) dysregulated in human obesity and to predict their possible target genes. Methods: We performed a systematic review on PubMed database (PROSPERO, CRD42017077742) for original works on c-miRNAs and human obesity and recorded c-miRNAs with differential expression profiles. Potential target genes and metabolic pathways for dysregulated miRNAs with at least two independent reports were searched using bioinformatic tools. Results: Twenty-two c-miRNAs are overexpressed, nine underexpressed and two c-miRNAs dysregulated in both directions in people with obesity compared to lean controls. Bioinformatic analyses suggest these c-miRNAs target on genes associated with fatty acid metabolism and PI3k/Akt pathway. Conclusion: Literature records 33 c-miRNAs confirmedly dysregulated in human obesity. Their predicted target genes are involved in pathways that could explain the development of obesity and its comorbidities. Further research will clarify the role of these miRNAs on metabolic diseases and their usefulness for the prognosis, prevention and treatment of obesity.

Obesity and dyslipidemia

Obesity, a pandemic of the modern world, is intimately associated with dyslipidemia, which is mainly driven by the effects of insulin resistance and pro-inflammatory adipokines. However, recent evidence suggests that obesity-induced dyslipidemia is not a unique pathophysiological entity, but rather has distinct characteristics depending on many individual factors. In line with that, in a subgroup of metabolically healthy obese (MHO) individuals, dyslipidemia is less prominent or even absent. In this review, we will address the main characteristics of dyslipidemia and mechanisms that induce its development in obesity. The fields, which should be further investigated to expand our knowledge on obesity-related dyslipidemia and potentially yield new strategies for prevention and management of cardiometabolic risk, will be highlighted. Also, we will discuss recent findings on novel lipid biomarkers in obesity, in particular proprotein convertase subtilisin/kexin type 9 (PCSK9), as the key molecule that regulates metabolism of low-density lipoproteins (LDL), and sphingosine-1-phosphate (S1P), as one of the most important mediators of high-density lipoprotein (HDL) particles function. Special attention will be given to microRNAs and their potential use as biomarkers of obesity-associated dyslipidemia.

miRNA Signature in NAFLD: A Turning Point for a Non-Invasive Diagnosis

Nonalcoholic fatty liver disease (NAFLD) defines a wide pathological spectrum ranging from simple steatosis to nonalcoholic steatohepatitis (NASH) which may predispose to liver cirrhosis and hepatocellular carcinoma. It represents the leading cause of hepatic damage worldwide. Diagnosis of NASH still requires liver biopsy but due to the high prevalence of NAFLD, this procedure, which is invasive, is not practicable for mass screening. Thus, it is crucial to non-invasively identify NAFLD patients at higher risk of progression to NASH and fibrosis. It has been demonstrated that hepatic fat content and progressive liver damage have a strong heritable component. Therefore, genetic variants associated with NAFLD have been proposed as non-invasive markers to be used in clinical practice. However, genetic variability is not completely explained by these common variants and it is possible that many of the phenotypic differences result from gene-environment interactions. Indeed, NAFLD development and progression is also modulated by epigenetic factors, in particular microRNAs (miRNAs), which control at post-transcriptional level many complementary target mRNAs and whose dysregulation has been shown to have high prognostic and predictive value in NAFLD. The premise of the current review is to discuss the role of miRNAs as pathogenic factors, risk predictors and therapeutic targets in NAFLD.

Anti-obesity activity of OBEX is regulated by activation of thermogenesis and decreasing adiposity gain

The incidence of obesity has been increasing dramatically worldwide over the past decades, thus requiring novel and effective therapeutic approaches. OBEX is an oral nutritional supplement composed of antioxidants with antiobesity activity. The effects of OBEX have been tested in vivo and in vitro. In vivo, OBEX reduces weight gain by decreasing adiposity gain and increasing energy expenditure in high fat diet-fed mice through the activation of thermogenesis in brown adipose tissue (BAT) independent of eating behaviors. In vitro analysis with 3T3-F442A cells revealed anti-proliferative and anti-differentiation effects of OBEX. In addition, OBEX induced a clear reduction of the lipid load in mature adipocytes obtained from 3T3-F442A cells. Overall, our findings suggest that OBEX has a protective effect against an obesogenic environment.

MicroRNA-based therapeutics in central nervous system injuries

Central nervous system (CNS) injuries, such as stroke, traumatic brain injury (TBI) and spinal cord injury (SCI), are important causes of death and long-term disability worldwide. MicroRNA (miRNA), small non-coding RNA molecules that negatively regulate gene expression, can serve as diagnostic biomarkers and are emerging as novel therapeutic targets for CNS injuries. MiRNA-based therapeutics include miRNA mimics and inhibitors (antagomiRs) to respectively decrease and increase the expression of target genes. In this review, we summarize current miRNA-based therapeutic applications in stroke, TBI and SCI. Administration methods, time windows and dosage for effective delivery of miRNA-based drugs into CNS are discussed. The underlying mechanisms of miRNA-based therapeutics are reviewed including oxidative stress, inflammation, apoptosis, blood-brain barrier protection, angiogenesis and neurogenesis. Pharmacological agents that protect against CNS injuries by targeting specific miRNAs are presented along with the challenges and therapeutic potential of miRNA-based therapies.

MiR17 improves insulin sensitivity through inhibiting expression of ASK1 and anti-inflammation of macrophages

OBJECTIVES

MicroRNAs (miRNAs) are involved in the pathological progression of various disease including type 2 diabetes (T2D). Chronic inflammation in adipose tissue is a cause of insulin resistance and T2D. MiR-17 palys an anti-inflammatory role in many biological processes. We hypothesized that miR-17 suppressed inflammatory macrophage that is related to insulin resistance in patients with T2D.

METHODS

Macrophage migration and secretion of inflammatory cytokines including TNF-α, IL-6 and IL-1β were detected through transwell migration assay and enzyme-linked immunosorbent assay, respectively. Insulin-stimulated glucose uptake was tested by the radioactivity of tritium-labeled glucose in 3T3-L1 adipocytes. Dual luciferase reporter gene assay was employed to evaluate the interaction between miR-17 and 3'UTR of ASK1.

RESULTS

Our results showed that miR-17 inhibited macrophage infiltration and secretion of TNF-α, IL-6 and IL-1β. Moreover, insulin-stimulated glucose uptake of 3T3-L1 was suppressed by treatment with LPS-induced macrophage conditioned media (CM), whereas the opposite effect was showed after treatment with the CM of macrophages transfected with miR-17. Furthermore, we found that miR-17 directly prevented expression of ASK1 by binding to its 3'UTR.

CONCLUSION

miR-17 improved inflammation-induced insulin resistance by suppressing ASK1 expression in macrophages. These results indicated that miR-17 had an anti-diabetic acitivity by its anti-inflammation effect on macrophage.

Targeting miRNA for Therapy of Juvenile and Adult Diabetic Cardiomyopathy

Prevalence of diabetes mellitus (DM), a multifactorial disease often diagnosed with high blood glucose levels, is rapidly increasing in the world. Association of DM with multi-organ dysfunction including cardiomyopathy makes it a leading cause of morbidity and mortality. There are two major types of DM: type 1 DM (T1D) and type 2 DM (T2D). T1D is diagnosed by reduced levels of insulin and high levels of glucose in the blood. It is caused due to pancreatic beta cell destruction/loss, and mostly found in juveniles (juvenile DM). T2D is diagnosed by increased levels of insulin and glucose in the blood. It is caused due to insulin receptor dysfunction, and mostly found in the adults (adult DM). Both T1D and T2D impair cardiac muscle function, which is referred to as diabetic cardiomyopathy. We and others have reported that miRNAs, a novel class of tiny non-coding regulatory RNAs, are differentially expressed in the diabetic heart and they contribute to diabetic cardiomyopathy. Here, we elaborated the biogenesis of miRNA, how miRNA regulates a gene, cardioprotective roles of different miRNAs including miRNAs present in exosomes, underlying molecular mechanisms by which miRNA ameliorates diabetic cardiomyopathy, and the role of miRNA as a potential therapeutic target for juvenile and adult diabetic cardiomyopathy.

TRIENNIAL GROWTH AND DEVELOPMENT SYMPOSIUM: Molecular mechanisms related to bovine intramuscular fat deposition in the longissimus muscle

The intramuscular fat (IMF) content of the LM, also known as marbling, is particularly important in determining the price of beef in Korea, Japan, and the United States. Deposition of IMF is influenced by both genetic (e.g., breed, gender, and genotype) and nongenetic factors (e.g., castration, nutrition, stressors, animal weight, and age). Castration of bulls markedly increases deposition of IMF, resulting in improved beef quality. Here, we present a comparative gene expression approach between bulls and steers. Transcriptomic and proteomic studies have demonstrated that the combined effects of increases in lipogenesis, fatty acid uptake, and fatty acid esterification and decreased lipolysis are associated with increased IMF deposition in the LM. Several peripheral tissues (LM, adipose tissues, and the liver) are involved in lipid metabolism. Therefore, understanding the significance of the tissue network in lipid metabolism is important. Here, we demonstrate that lipid metabolism in LM tissues is crucial for IMF deposition, whereas lipid metabolism in the liver plays only a minor role. Metabolism of body fat and IMF deposition in bovine species has similarities with these processes in metabolic diseases, such as obesity in humans and rodents. Extensive studies on metabolic diseases using epigenome modification (DNA methylation, histone modification, and microRNA), microbial metagenomics, and metabolomics have been performed in humans and rodents, and new findings have been reported using these technologies. The importance of applying "omics" fields (epigenomics, metagenomics, and metabolomics) to the study of IMF deposition in cattle is described. New information on the molecular mechanisms of IMF deposition may be used to design nutritional or genetic methods to manipulate IMF deposition and to modify fatty acid composition in beef cattle. Applying nutrigenomics could maximize the expression of genetic potential of economically important traits (e.g., marbling) in animals.

Small non coding RNAs in adipocyte biology and obesity

Obesity has reached epidemic proportions world-wide and constitutes a substantial risk factor for hypertension, type 2 diabetes, cardiovascular diseases and certain cancers. So far, regulation of energy intake by dietary and pharmacological treatments has met limited success. The main interest of current research is focused on understanding the role of different pathways involved in adipose tissue function and modulation of its mass. Whole-genome sequencing studies revealed that the majority of the human genome is transcribed, with thousands of non-protein-coding RNAs (ncRNA), which comprise small and long ncRNAs. ncRNAs regulate gene expression at the transcriptional and post-transcriptional level. Numerous studies described the involvement of ncRNAs in the pathogenesis of many diseases including obesity and associated metabolic disorders. ncRNAs represent potential diagnostic biomarkers and promising therapeutic targets. In this review, we focused on small ncRNAs involved in the formation and function of adipocytes and obesity.

Circulating microRNAs: Possible role as non-invasive diagnostic biomarkers in liver disease

Liver is the central organ for metabolism and the hepatocytes metabolize several drugs, hepatotoxins, alcohol, etc. Continuous exposure of the hepatocytes to these toxins result in various chronic diseases, such as alcoholic liver disease, non-alcoholic fatty liver disease, viral hepatitis and hepatocellular carcinoma. Although several diagnostic methods, such as serum markers, liver biopsy or imaging studies are currently available, most of these are either invasive or detect the disease at advanced stages. Hence, there is a need for new molecular markers that can be used for early detection of the disease. MicroRNAs (miRNAs) are naturally occurring, 20-22 nucleotide long, non-coding RNA molecules that regulate the gene expression at post-transcriptional levels, thereby modulating various biological functions. Their expression is deregulated under pathological conditions, and recent studies showed that they are secreted and can be detected in various body fluids. Since the cellular changes occur at earlier stages of the disease, detecting miRNAs in the body fluids could make them as potential novel biomarkers. Albeit, the difficulties in standardization procedures, cost and availability should be addressed before using them in the clinical arena. This review highlights the possible role of secreted miRNAs to use as early non-invasive diagnostic markers for liver disease.

miR155 deficiency aggravates high-fat diet-induced adipose tissue fibrosis in male mice

Noncoding RNAs are emerging as regulators of inflammatory and metabolic processes. There is evidence to suggest that miRNA155 (miR155) may be linked to inflammation and processes associated with adipogenesis. We examined the impact of global miRNA-155 deletion (miR155-/-) on the development of high-fat diet (HFD)-induced obesity. We hypothesized that loss of miR155 would decrease adipose tissue inflammation and improve the metabolic profile following HFD feedings. Beginning at 4-5 weeks of age, male miR155-/- and wild-type (WT) mice (n = 13-14) on a C57BL/6 background were fed either a HFD or low-fat diet for 20 weeks. Body weight was monitored throughout the study. Baseline and terminal body composition was assessed by DEXA analysis. Adipose tissue mRNA expression (RT-qPCR) of macrophage markers (F4/80, CD11c, and CD206) and inflammatory mediators (MCP-1 and TNF-α) as well as adiponectin were measured along with activation of NFκB-p65 and JNK and PPAR-γ Adipose tissue fibrosis was assessed by picrosirius red staining and western blot analysis of Collagen I, III, and VI. Glucose metabolism and insulin resistance were assessed by Homeostatic Model Assessment - Insulin Resistance (HOMA-IR), and a glucose tolerance test. Compared to WT HFD mice, miR155-/- HFD mice displayed similar body weights, yet reduced visceral adipose tissue accumulation. However, miR155-/- HFD displayed exacerbated adipose tissue fibrosis and decreased PPAR-γ protein content. The loss of miR155 did not affect adipose tissue inflammation or glucose metabolism. In conclusion, miR155 deletion did not attenuate the development of the obese phenotype, but adipose tissue fibrosis was exacerbated, possibly through changes to adipogenic processes.

Tumor necrosis factor‑α and interleukin‑6 suppress microRNA‑1275 transcription in human adipocytes through nuclear factor‑κB

Obesity is a confirmed risk factor for hyperlipidemia, type-II diabetes, hypertension, and cardiovascular disease. MicroRNAs (miRs) have emerged as an important field of study within energy metabolism and obesity. A previous study demonstrated miR-1275 to be markedly down-regulated during maturation of human preadipocytes. It has been reported that miR-1275 dysregulates expression in several types of cancer and infections. Little is currently known about the regulation of miR-1275 transcription. The aim of the current study was to explore the mechanism underlying the expression of miR-1275 in mature human adipocytes. After differentiation, human adipocytes were incubated with tumor necrosis factor (TNF)-α and interleukin-6. The results of reverse transcription-quantitative polymerase chain reaction demonstrated that miR-1275 can be down-regulated by TNF-α and IL-6, in human mature adipocytes. Bioinformatic analysis was used to predict nuclear factor (NF)-κB binding sites of miR-1275′s promoter region. Luciferase assay and rescue experiments were performed in HEK293T cells. NF-κB was involved in regulating miR-1275 transcription by binding to its promoter. In response to TNF-α, NF-κB was bound to the promoter of miR-1275 and inhibited its transcription. These results indicated that inflammatory factors could regulate miR-1275 transcription through NF-κB and influencing miR-1275 effects on obesity.

Prevention of diabetes in overweight/obese children through a family based intervention program including supervised exercise (PREDIKID project): study protocol for a randomized controlled trial

BACKGROUND

The global pandemic of obesity has led to an increased risk for prediabetes and type-2 diabetes (T2D). The aims of the current project are: (1) to evaluate the effect of a 22-week family based intervention program, including supervised exercise, on insulin resistance syndrome (IRS) risk in children with a high risk of developing T2D and (2) to identify the profile of microRNA in circulating exosomes and in peripheral blood mononuclear cells in children with a high risk of developing T2D and its response to a multidisciplinary intervention program including exercise.

METHODS

A total of 84 children, aged 8-12 years, with a high risk of T2D will be included and randomly assigned to control (N = 42) or intervention (N = 42) groups. The control group will receive a family based lifestyle education and psycho-educational program (2 days/month), while the intervention group will attend the same lifestyle education and psycho-educational program plus the exercise program (3 days/week, 90 min per session including warm-up, moderate to vigorous aerobic activities, and strength exercises). The following measurements will be evaluated at baseline prior to randomization and after the intervention: fasting insulin, glucose and hemoglobin A1c; body composition (dual-energy X-ray absorptiometry); ectopic fat (magnetic resonance imaging); microRNA expression in circulating exosomes and in peripheral blood mononuclear cells (MiSeq; Illumina); cardiorespiratory fitness (cardiopulmonary exercise testing); dietary habits and physical activity (accelerometry).

DISCUSSION

Prevention and identification of children with a high risk of developing T2D could help to improve their cardiovascular health and to reduce the comorbidities associated with obesity.

TRIAL REGISTRATION

ClinicalTrials.gov, ID: NCT03027726 . Registered on 16 January 2017.

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.

Fish Oil Feeding Modulates the Expression of Hepatic MicroRNAs in a Western-Style Diet-Induced Nonalcoholic Fatty Liver Disease Rat Model

Nonalcoholic fatty liver disease (NAFLD) is one of the most prevalent chronic liver diseases worldwide. Recent studies have indicated that fish oil supplementation has benefits against NAFLD. Our previous transcriptomic study has validated the effect of fish oil supplementation on altering hepatic gene expression in a NAFLD rat model. In the current study, we examined the effects of fish oil on the expression of hepatic microRNAs. Male Sprague–Dawley rats were fed with a lab chow (CON), high-fat high-cholesterol diet (WD), or WD supplemented with fish oil (FOH), respectively. Small RNAs were extracted from livers for RNA-sequencing. A total of 79 miRNAs were identified as differentially expressed miRNAs (DEMs) between FOH and WD groups, exemplified by rno-miR-29c-3p, rno-miR-30d-5p, rno-miR-33-5p, rno-miR-34a, and rno-miR-328a-3p. Functional annotation of DEMs predicted target genes suggested that the altered hepatic miRNAs contributed to fish oil modification of hepatic lipid metabolism and signaling transduction. Integrative analysis of DEMs and differentially expressed genes suggested that the expression difference of Pcsk9, Insig2, Per3, and Socs1/3 between FOH and WD groups may be due to miRNA modification. Our study reveals that fish oil supplementation alters hepatic expression of miRNAs, which may contribute to fish oil amelioration of NAFLD in rats.

Pentamethylquercetin induces adipose browning and exerts beneficial effects in 3T3-L1 adipocytes and high-fat diet-fed mice

Browning white adipocytes may be a new target in anti-obesity therapy. Pentamethylquercetin (PMQ) has been shown to have anti-obesity effects in monosodium glutamate-induced obese mice. Here, we aimed to study the anti-obesity effects of PMQ in vitro and in vivo and to determine if adipose browning is involved in the mechanism underlying the anti-obesity effects of PMQ. We evaluated the effects of PMQ on cell proliferation, cell differentiation, glucose consumption, cellular lipid metabolism, and related brown gene expression in 3T3-L1 adipocytes. We also investigated the effects of PMQ in a mouse model of high-fat diet (HFD)-induced obesity. Our results demonstrated that PMQ increased the consumption of glucose, inhibited the accumulation of cellular triglycerides (TGs), and induced the expression of brown adipocyte-specific genes, such as uncoupling protein 1 (UCP-1), during the early stage of differentiation in 3T3-L1 adipocytes. In HFD mice, PMQ treatment reduced waist circumference, LEE index, white adipose tissue (WAT) weight and white adipocyte size and increased brown adipose tissue (BAT) weight. Moreover, PMQ treatment induced mitochondrial biogenesis and upregulated UCP-1 expression in WAT. These findings suggest that PMQ may induce browning of adipose tissue, a phenomenon that is at least partly related to its anti-obesity effects.

Visualization and Analysis of MiRNA-Targets Interactions Networks

MicroRNAs are a class of small, noncoding RNA molecules of 21-25 nucleotides in length that regulate the gene expression by base-pairing with the target mRNAs, mainly leading to down-regulation or repression of the target genes. MicroRNAs are involved in diverse regulatory pathways in normal and pathological conditions. In this context, it is highly important to identify the targets of specific microRNA in order to understand the mechanism of its regulation and consequently its involvement in disease. However, the microRNA target identification is experimentally laborious and time-consuming. The in silico prediction of microRNA targets is an extremely useful approach because you can identify potential mRNA targets, reduce the number of possibilities and then, validate a few microRNA-mRNA interactions in an in vitro experimental model. In this chapter, we describe, in a simple way, bioinformatics guidelines to use miRWalk database and Cytoscape software for analyzing microRNA-mRNA interactions through their visualization as a network.

The Emerging Role of Epigenetics in Inflammation and Immunometabolism

Recent research developments have shed light on the risk factors contributing to metabolic complications, implicating both genetic and environmental factors, potentially integrated by epigenetic mechanisms. Distinct epigenetic changes in immune cells are frequently observed in obesity and type 2 diabetes mellitus, and these are associated with alterations in the phenotype, function, and trafficking patterns of these cells. The first step in the development of effective therapeutic strategies is the identification of distinct epigenetic signatures associated with metabolic disorders. In this review we provide an overview of the epigenetic mechanisms influencing immune cell phenotype and function, summarize current knowledge about epigenetic changes affecting immune functions in the context of metabolic diseases, and discuss the therapeutic options currently available to counteract epigenetically driven metabolic complications.

Maternal pre-pregnancy body mass index and circulating microRNAs in pregnancy

BACKGROUND

Maternal pre-pregnancy overweight and obese status has been associated with a number of pregnancy complications and adverse offspring outcomes. Mechanisms for observed associations, however, are largely unknown. We investigated associations of pre-pregnancy body mass index with early-mid pregnancy epigenetic biomarkers, circulating microRNAs.

METHODS

Peripheral blood was collected from participants (16-27 weeks gestation) of two multi-racial pregnancy cohorts, the Omega Study and the Pregnancy Outcomes and Community Health Study. Plasma miRNA expression was characterised using epigenome-wide (319 miRNAs) profiling among 20 pregnant women in each cohort. Cohort-specific linear regression models that included the predictor (pre-pregnancy body mass index), the outcome (microRNA expression), and adjustment factors (maternal age, gestational age at blood collection, and race) were fit.

RESULTS

Expression of 27 miRNAs was positively associated with pre-pregnancy body mass index in both cohorts (p-values <0.05). A number of these differentially expressed miRNAs have previously been associated with adipogenesis (e.g. let-7d*, miR-103-2*, -130b, -146b-5-p, -29c, and -26b). Identified miRNAs as well as their experimentally validated targets participate in pathways that involve organismal injury, reproductive system disease, connective tissue disorders, cancer, cellular development, growth and proliferation.

CONCLUSION

Pre-pregnancy body mass index is associated with circulating miRNAs in early-mid pregnancy.

Renal Carcinogenesis, Tumor Heterogeneity, and Reactive Oxygen Species: Tactics Evolved

SIGNIFICANCE

The number of kidney cancers is growing 3-5% each year due to unknown etiologies. Intra- and inter-tumor mediators increase oxidative stress and drive tumor heterogeneity. Recent Advances: Technology advancement in state-of-the-art instrumentation and methodologies allows researchers to detect and characterize global landscaping modifications in genes, proteins, and pathophysiology patterns at the single-cell level.

CRITICAL ISSUES

We postulate that the sources of reactive oxygen species (ROS) and their activation within subcellular compartments will change over a timeline of tumor evolvement and contribute to tumor heterogeneity. Therefore, the complexity of intracellular changes within a tumor and ROS-induced tumor heterogeneity coupled to the advancement of detecting these events globally are limited at the level of data collection, organization, and interpretation using software algorithms and bioinformatics.

FUTURE DIRECTIONS

Integrative and collaborative research, combining the power of numbers with careful experimental design, protocol development, and data interpretation, will translate cancer biology and therapeutics to a heightened level or leave the abundant raw data as stagnant and underutilized. Antioxid. Redox Signal. 25, 685-701.

The Role of MicroRNAs and Their Targets in Osteoarthritis

Micro ribonucleic acid (microRNA) regulation and expression has become an emerging field in determining the mechanisms regulating a variety of inflammation-mediated diseases. Several studies have focused on specific microRNAs that are differentially expressed in cases of osteoarthritis. Furthermore, several targets of these miRNAs important in disease progression have also been identified. In this review, we focus on microRNA biogenesis, regulation, detection, and quantification with an emphasis on cellular localization and how these concepts may be linked to disease processes such as osteoarthritis. Next, we review the relationships of specific microRNAs to certain features and risk factors associated with osteoarthritis such as inflammation, obesity, autophagy, and cartilage homeostasis. We also identify certain microRNAs that are differentially expressed in osteoarthritis but have unidentified targets and functions in the disease state. Lastly, we identify the potential use of microRNAs for therapeutic purposes and also mention certain remedies that regulate microRNA expression.

From Genome-Wide Association Study to Phenome-Wide Association Study: New Paradigms in Obesity Research

Obesity is a condition in which excess body fat has accumulated over an extent that increases the risk of many chronic diseases. The current clinical classification of obesity is based on measurement of body mass index (BMI), waist-hip ratio, and body fat percentage. However, these measurements do not account for the wide individual variations in fat distribution, degree of fatness or health risks, and genetic variants identified in the genome-wide association studies (GWAS). In this review, we will address this important issue with the introduction of phenome, phenomics, and phenome-wide association study (PheWAS). We will discuss the new paradigm shift from GWAS to PheWAS in obesity research. In the era of precision medicine, phenomics and PheWAS provide the required approaches to better definition and classification of obesity according to the association of obese phenome with their unique molecular makeup, lifestyle, and environmental impact.

The Fto Gene Regulates the Proliferation and Differentiation of Pre-Adipocytes in Vitro

The highly regulated differentiation and proliferation of pre-adipocytes play a key role in the initiation of obesity. Fat mass and obesity associated (FTO) is a novel gene strongly associated with the risk of obesity. A deficiency of FTO may cause growth retardation in addition to fat mass and adipocyte size reduction in vivo. To investigate the potential role of Fto gene on the proliferation and differentiation of pre-adipocytes, we generated Fto-knockdown and overexpressed 3T3-L1 cells. Using numerous proliferation assays our results suggest that Fto knockdown leads to suppression of proliferation, lower mitochondrial membrane potential, less cellular ATP, and decreased and smaller intracellular lipid droplets compared with controls (p < 0.05). Western blot analysis demonstrated that Fto knockdown can significantly suppress peroxisome proliferator-activated receptor gamma (PPARγ) and glucose transporter type 4 (GLUT4) expression and inhibit Akt phosphorylation. By contrast, overexpression of Fto had the opposing effect on proliferation, mitochondrial membrane potential, ATP generation, in vitro differentiation, Akt phosphorylation, and PPARγ and GLUT4 expression. Moreover, we demonstrated that Wortmannin, a phosphoinositide 3-kinase (PI3K) inhibitor, could inhibit phospho-Akt in Fto overexpressed 3T3-L1 cells. Taken together, the results suggest that Fto regulates the proliferation and differentiation of 3T3-L1 cells via multiple mechanisms, including PPARγ and PI3K/Akt signaling.

Circulating microRNAs in nonalcoholic fatty liver disease

Liver biopsy is currently recognized as the most accurate method for diagnosing and staging nonalcoholic fatty liver disease (NAFLD). However, this procedure is typically performed when disease has progressed to clinically significant stages, thereby limiting early diagnosis of patients who are at high risk for development of liver- and cardiovascular-related morbidity and mortality. Recently, microRNAs (miRNAs), short, noncoding RNAs that regulate gene expression, have been associated with histological features of NAFLD and are readily detected in the circulation. As such, miRNAs are emerging as potentially useful noninvasive markers with which to follow the progression of NAFLD. In this article, we present the evidence linking circulating miRNAs with NAFLD and discuss the potential value of circulating miRNA profiles in the development of improved methods for NAFLD diagnosis and clinical monitoring of disease progression.