Adaptive expression of microRNA-125a in adipose tissue in response to obesity in mice and men

Identification of mRNA Degradome Variation Dependent on Divergent Muscle Mass in Different Pig Breeds

The search is still on for the molecular processes associated with the development and metabolism of skeletal muscles. Selection conducted in farm animals is focused on high muscle mass because it delivers higher economic profit. The present study aimed to shed light on mRNA degradome signals that could be characteristic for molecular processes associated with an abundance of muscle mass and to identify miRNA regulatory networks controlling these processes in pigs applying next-generation-sequencing (NGS). In the study, over 10,000 degraded transcripts were identified per sample, with the highest abundance for genes encoding mitochondrial proteins (COXs, NDs, CYTB, ATP6 and ATP8). Moreover, only 26% of the miRNA targets were found within this degraded transcript pool, which suggested for miRNAs other molecular mechanism at different level of gene expression than mRNA degradation. On the other hand, a small share of the identified degraded transcripts associated with miRNA regulation suggests a different mechanism of mRNA degradation for identified degraded transcropts. Subsequently, most of the miRNA gene degraded targets, such as ENO3, CKM, CRYAB and ADAM19 encode proteins involved in the muscle mass control. The present study showed an interesting dependence between miRNAs and their targets. Nevertheless, the complete view of the miRNA regulatory network could be a subject of further advanced research, which would employ a miRNA transfection procedure in skeletal muscle cell cultures.

Metabogenomics reveals four candidate regions involved in the pathophysiology of Equine Metabolic Syndrome

An analogous condition to human metabolic syndrome, Equine Metabolic Syndrome (EMS) is defined by several clinical signs including obesity, hyperinsulinemia, and peripheral insulin dysregulation (ID). Affected horses may also exhibit hypertension, hyperlipemia and systemic inflammation. Measures of ID typically comprise the gold-standard for diagnosis in veterinary care. Yet, the dynamic nature of insulin homeostasis and complex procedures of typical assays make accurate quantification of ID and EMS challenging. This work aimed to investigate new strategies for identification of biochemical markers and correlated genes in EMS. To quantify EMS risk within this population, we utilized a composite score derived from nine common diagnostic variables. We applied a global liquid chromatography/mass spectroscopy approach (HPLC/MS) to whole plasma collected from 49 Arabian horses, resulting in 3392 high-confidence features and identification of putative metabolites in public databases. We performed a genome wide association analysis with genotypes from the 670k Affymetrix Equine SNP array utilizing EMS-correlated metabolites as phenotypes. We discovered four metabolite features significantly correlated with EMS score (P < 1.474 × 10^-5). GWAs for these features results (P = 6.787 × 10^-7, Bonferroni) identified four unique candidate regions (r² > 0.4) containing 63 genes. Significant genomic markers capture 43.52% of the variation in the original EMS score phenotype. The identified genomic loci provide insight into the pathways controlling variation in EMS and the origin of genetic predisposition to the condition. Rapid, feasible and accurate diagnostic tools derived from metabogenomics can be translated into measurable benefits in the timeline and quality of preventative management practices to preserve health in horses.

Integrated Transcriptome Analysis of Human Visceral Adipocytes Unravels Dysregulated microRNA-Long Non-coding RNA-mRNA Networks in Obesity and Colorectal Cancer

Obesity, and the obesity-associated inflammation, represents a major risk factor for the development of chronic diseases, including colorectal cancer (CRC). Dysfunctional visceral adipose tissue (AT) is now recognized as key player in obesity-associated morbidities, although the biological processes underpinning the increased CRC risk in obese subjects are still a matter of debate. Recent findings have pointed to specific alterations in the expression pattern of non-coding RNAs (ncRNAs), such as microRNAs (miRNAs), and long non-coding RNAs (lncRNAs), as mechanisms underlying dysfunctional adipocyte phenotype in obesity. Nevertheless, the regulatory networks and interrelated processes relevant for adipocyte functions, that may contribute to a tumor-promoting microenvironment, are poorly known yet. To this end, based on RNA sequencing data, we identified lncRNAs and miRNAs, which are aberrantly expressed in visceral adipocytes from obese and CRC subjects, as compared to healthy lean control, and validated a panel of modulated ncRNAs by real-time qPCR. Furthermore, by combining the differentially expressed lncRNA and miRNA profiles with the transcriptome analysis dataset of adipocytes from lean and obese subjects affected or not by CRC, lncRNA-miRNA-mRNA adipocyte networks were defined for obese and CRC subjects. This analysis highlighted several ncRNAs modulation that are common to both obesity and CRC or unique of each disorder. Functional enrichment analysis of network-related mRNA targets, revealed dysregulated pathways associated with metabolic processes, lipid and energy metabolism, inflammation, and cancer. Moreover, adipocytes from obese subjects affected by CRC exhibited a higher complexity, in terms of number of genes, lncRNAs, miRNAs, and biological processes found to be dysregulated, providing evidence that the transcriptional and post-transcriptional program of adipocytes from CRC patients is deeply affected by obesity. Overall, this study adds further evidence for a central role of visceral adipocyte dysfunctions in the obesity-cancer relationship.

Expression profiling and analysis of some miRNAs in subcutaneous white adipose tissue during development of obesity

Background

MicroRNAs are emerging as new mediators in the regulation of adipocyte physiology and have been approved to play a role in obesity. Despite several studies have focused on microRNA expression profiles and functions in different metabolic tissues, little is known about their response to nutritional interventions in white adipose tissue during obesity stages, and whether they differ in this response to weight-reduction strategy is poorly understood. Our objectives were to study the dysregulation of some miRNAs in subcutaneous inguinal white adipose tissue during weight change, expansion/reduction; in response to both a high-fat diet and switching to a normal diet feeding, and to evaluate them as potential biomarkers and therapeutic targets for early obesity management

Method

A hundred 6-week-old male Wister rats were randomly divided into a normal diet group (N.D), a high-fat diet group (H.F.D), and a switched to a normal diet group (H.F.D/N.D). At the beginning and at intervals 2 weeks, serum lipid, hormone levels, total body fat mass, and inguinal subcutaneous white adipose tissue mass (WAT) measurements were recorded using dual-energy X-ray absorptiometry (DEXA). The expression levels of microRNAs were evaluated using real-time PCR.

Results

Significant alterations were observed in serum glucose, lipid profile, and adipokine hormones during the early stages of obesity development. Alteration in rno-mir 30a-5p, rno-mir 133a-5p, and rno-mir 107-5p expression levels were observed at more than one time point. While rno-let-7a-5p, rno-mir 193a-5p, and rno-mir125a-5p were downregulated and rno-mir130a-5p was upregulated at all time points within 2 to 4 weeks in response to H.F.D feeding for 10 weeks. The impact of switching to normal diet has a reversed effect on lipid profile, adipokine hormone levels, and some miRNAs. The bioinformatics results have identified a novel and important pathway related to inflammatory signalling.

Conclusion

Our research demonstrated significant alterations in some adipocyte-expressed miRNAs after a short time of high caloric diet consumption. This provides further evidence of the significant role of nutrition as an epigenetic factor in regulation of lipid and glucose metabolism genes by modulating of related key miRNAs. Therefore, we suggest that miRNAs could be used as biomarkers for adiposity during diet-induced obesity. Perhaps limitation in calories intake is a way to manipulate obesity and associated metabolic disorders. Further studies are needed to fully elucidate the role of microRNAs in the development of obesity

Dysregulation of microRNA-125a contributes to obesity-associated insulin resistance and dysregulates lipid metabolism in mice

Obesity is associated with an increased risk of developing insulin resistance (IR) and type 2 diabetes (T2D). A diverse group of factors including miRNA has been implicated in the pathogenesis of these two metabolic conditions, although underlying molecular mechanisms involved are not well defined. Here, we provide evidence that hepatic miR-125a levels are diminished in both genetic as well as dietary mouse models of obesity. Overexpression of miR-125a enhanced insulin signaling and attenuated cellular lipid accumulation in HepG2 cells and Hepa1-6 cells. Likewise, treatment of mice with ago-miR-125a increased insulin sensitivity, similar to overexpression of miR-125a, whereas treatment of mice with antago-miR-125a blunted the insulin sensitivity. Furthermore, overexpression of miR-125a in mice previously fed a high-fat diet (HFD), significantly improved insulin sensitivity, and attenuated obesity-linked hepatic steatosis and hepatocyte lipid accumulation. In addition, we show that ELOVL fatty acid elongase 6 (Elovl6) is a direct target of miR-125a, and participates in miR-125a mediated regulation of insulin sensitivity and lipid metabolism. These data led us to conclude that dysregulated miR-125a expression augments the development of obesity-induced IR and that miR-125a might serve as a therapeutic target for the development of new drug(s) in the clinical management of metabolic diseases.

MicroRNA-125a-5p Affects Adipocytes Proliferation, Differentiation and Fatty Acid Composition of Porcine Intramuscular Fat

Intramuscular fat (IMF) content and composition are considered crucial indicators of porcine meat quality. However, the molecular mechanism of porcine IMF development is still mostly unclear. Recently, new evidence suggested that microRNA (miRNAs) play important roles in porcine intramuscular adipogenesis. Previously, microRNA-125a-5p (miR-125a-5p) was identified as an important regulator of adipogenesis. In the present study, we found that the expression of miR-125a-5p is dynamically regulated during porcine intramuscular preadipocytes differentiation and that its expression levels in different porcine muscle tissues were negatively involved with IMF content. To investigate the potential function role of miR-125a-5p in IMF development, porcine intramuscular preadipocytes were collected and transfected with miR-125a-5p mimics, inhibitors, or a negative control (NC), respectively. The results showed that overexpression of miR-125a-5p promoted proliferation and inhibited differentiation of porcine intramuscular preadipocytes while inhibition of miR-125a-5p had the opposite effects. Furthermore, a luciferase reporter assay demonstrated that porcine kruppel like factor 3 (KLF13) is a target gene of miR-125a-5p during porcine intramuscular preadipocytes differentiation. Interestingly, porcine ELOVL fatty acid elongase 6 (ELOVL6), a regulator of fatty acid composition, was also identified as a target gene of miR-125a-5p during porcine intramuscular adipogenesis. Further studies show that miR-125a-5p overexpression reduced total saturated fatty acids (SFA) content and monounsaturated fatty acids (MUFA)/SFA ratios while having no significant impact on polyunsaturated fatty acids (PUFA)/SFA and n-6/n-3 ratios. Taken together, our results identified that miR-125a-5p may be a novel regulator of porcine intramuscular adipogenesis and the fatty acid composition of porcine IMF.

The clinical potential of adipogenesis and obesity-related microRNAs

Obesity is a growing health problem commonly associated with numerous metabolic disorders including type 2 diabetes, hypertension, cardiovascular disease, and some forms of cancer. The burden of obesity and associated cardiometabolic diseases are believed to arise through complex interplay between genetics and epigenetics predisposition, nutrition, environment, and lifestyle. However, the molecular basis and the repertoire of obesity-affecting factors are still unknown. Emerging evidence is connecting microRNAs (miRNAs) dysregulation with adipogenesis and obesity. Alteration in miRNAs expression could result in changes in the pattern of genes controlling a range of biological processes including inflammation, lipid metabolism, insulin resistance and adipogenesis. Hence, understanding exact roles of miRNAs as well as the degree of their contribution to the regulation of adipogenesis and fat cell development in obesity would provide new therapeutic targets for the development of novel and effective anti-obesity drugs. The objective of the current review is to: (i) discuss some of the latest development on relevant miRNAs dysregulation mainly in human adipogenesis and obesity, (ii) emphasize the role of circulating miRNAs as new promising therapeutics and attractive potential biomarkers for treating obesity and associated risk factor diseases, (iii) describe how dietary factors may influence obesity through modulation of miRNAs expression, (iv) highlight some of the actual limitations to the promise of miRNAs as novel therapeutics as well as to their translation for the benefit of patients, and finally (v) provide recommendations for future research on miRNA-based therapeutics that could lead to a breakthrough in the treatment of obesity and its associated pathologies.

The role of complement system in adipose tissue-related inflammation

As the common factor linking adipose tissue to the metabolic context of obesity, insulin resistance and atherosclerosis are associated with a low-grade chronic inflammatory status, to which the complement system is an important contributor. Adipose tissue synthesizes complement proteins and is a target of complement activation. C3a-desArg/acylation-stimulating protein stimulates lipogenesis and affects lipid metabolism. The C3a receptor and C5aR are involved in the development of adipocytes' insulin resistance through macrophage infiltration and the activation of adipose tissue. The terminal complement pathway has been found to be instrumental in promoting hyperglycemia-associated tissue damage, which is characteristic of the major vascular complications of diabetes mellitus and diabetic ketoacidosis. As a mediator of the effects of the terminal complement complex C5b-9, RGC-32 has an impact on energy expenditure as well as lipid and glucose metabolic homeostasis. All of this evidence, taken together, indicates an important role for complement activation in metabolic diseases.

Caloric restriction impacts plasma microRNAs in rhesus monkeys

Caloric restriction (CR) is one of the most robust interventions shown to delay aging in diverse species, including rhesus monkeys (Macaca mulatta). Identification of factors involved in CR brings a promise of translatability to human health and aging. Here, we show that CR induced a profound change in abundance of circulating microRNAs (miRNAs) linked to growth and insulin signaling pathway, suggesting that miRNAs are involved in CR's mechanisms of action in primates. Deep sequencing of plasma RNA extracts enriched for short species revealed a total of 243 unique species of miRNAs including 47 novel species. Approximately 70% of the plasma miRNAs detected were conserved between rhesus monkeys and humans. CR induced or repressed 24 known and 10 novel miRNA species. Regression analysis revealed correlations between bodyweight, adiposity, and insulin sensitivity for 10 of the CR-regulated known miRNAs. Sequence alignment and target identification for these 10 miRNAs identify a role in signaling downstream of the insulin receptor. The highly abundant miR-125a-5p correlated positively with adiposity and negatively with insulin sensitivity and was negatively regulated by CR. Putative target pathways of CR-associated miRNAs were highly enriched for growth and insulin signaling that have previously been implicated in delayed aging. Clustering analysis further pointed to CR-induced miRNA regulation of ribosomal, mitochondrial, and spliceosomal pathways. These data are consistent with a model where CR recruits miRNA-based homeostatic mechanisms to coordinate a program of delayed aging.

Micro RNAs and DNA methylation are regulatory players in human cells with altered X chromosome to autosome balance

The gene balance hypothesis predicts that an imbalance in the dosage sensitive genes affects the cascade of gene networks that may influence the fitness of individuals. The phenotypes associated with chromosomal aneuploidies demonstrate the importance of gene dosage balance. We have employed untransformed human fibroblast cells with different number of X chromosomes to assess the expression of miRNAs and autosomal genes in addition to the DNA methylation status. High throughput NGS analysis using illumina Next seq500 has detected several autosomal as well as X linked miRNAs as differentially expressed in X monosomy and trisomy cells. Two of these miRNAs (hsa-miR-125a-5p and 335-5p) are likely to be involved in regulation of the autosomal gene expression. Additionally, our data demonstrates altered expression and DNA methylation signatures of autosomal genes in X monosomy and trisomy cells. In addition to miRNAs, expression of DNMT1 which is an important epigenetic player involved in many processes including cancer, is seen to be altered. Overall, present study provides a proof for regulatory roles of micro RNAs and DNA methylation in human X aneuploidy cells opening up possible new ways for designing therapeutic strategies.

Joint Profiling of miRNAs and mRNAs Reveals miRNA Mediated Gene Regulation in the Göttingen Minipig Obesity Model

Obesity and its comorbidities are an increasing challenge for both affected individuals and health care systems, worldwide. In obese individuals, perturbation of expression of both protein-coding genes and microRNAs (miRNA) are seen in obesity-relevant tissues (i.e. adipose tissue, liver and skeletal muscle). miRNAs are small non-coding RNA molecules which have important regulatory roles in a wide range of biological processes, including obesity. Rodents are widely used animal models for human diseases including obesity. However, not all research is applicable for human health or diseases. In contrast, pigs are emerging as an excellent animal model for obesity studies, due to their similarities in their metabolism, their digestive tract and their genetics, when compared to humans. The Göttingen minipig is a small sized easy-to-handle pig breed which has been extensively used for modeling human obesity, due to its capacity to develop severe obesity when fed ad libitum. The aim of this study was to identify differentially expressed of protein-coding genes and miRNAs in a Göttingen minipig obesity model. Liver, skeletal muscle and abdominal adipose tissue were sampled from 7 lean and 7 obese minipigs. Differential gene expression was investigated using high-throughput quantitative real-time PCR (qPCR) on 90 mRNAs and 72 miRNAs. The results revealed de-regulation of several obesity and inflammation-relevant protein-coding genes and miRNAs in all tissues examined. Many genes that are known to be de-regulated in obese humans were confirmed in the obese minipigs and several of these genes have target sites for miRNAs expressed in the opposing direction of the gene, confirming miRNA-mediated regulation in obesity. These results confirm the translational value of the pig for human obesity studies.

Biological roles of microRNAs in the control of insulin secretion and action

microRNAs (miRNAs) are intracellular and circulating molecular components contributing to genome expression control through binding mRNA targets, which generally results in downregulated mRNA expression. One miRNA can target several mRNAs, and one transcript can be targeted by several miRNAs, resulting in complex fine-tuning of regulation of gene networks and signaling pathways. miRNAs regulate metabolism, adipocyte differentiation, pancreatic development, β-cell mass, insulin biosynthesis, secretion, and signaling, and their role in diabetes and obesity is emerging. Their pathophysiological effects are essentially dependent on cellular coexpression with their mRNA targets, which can show tissue-specific transcriptional responses to disease conditions and environmental challenges. Current knowledge of miRNA biology and their impact on the pathogenesis of diabetes and obesity is based on experimental data documenting miRNA expression generally in single tissue types that can be correlated with expression of target mRNAs to integrate miRNA in functional pathways and gene networks. Here we present results from the most significant studies dealing with miRNA function in liver, fat, skeletal muscle, and endocrine pancreas and their implication in diabetes and obesity.

SIRT1 and SIRT7 expression in adipose tissues of obese and normal-weight individuals is regulated by microRNAs but not by methylation status

BACKGROUND/OBJECTIVE

Given their importance in the regulation of metabolism, sirtuins (SIRTs) constitute promising subjects of research on the pathogenesis of obesity and the metabolic syndrome. The aim of this study was to assess whether obesity in humans is associated with changes in the expression of SIRT genes in adipose tissue and whether epigenetic mechanisms, DNA methylation and microRNA (miRNA) interference, mediate in this phenomenon.

SUBJECTS/METHODS

The expression of SIRTs and of SIRT1 and SIRT7 mRNA-interacting miRNAs was evaluated by real-time PCR in visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) of 58 obese (body mass index (BMI) >40 kg m^-2) and 31 normal-weight (BMI 20-24.9 kg m^-2) individuals. The methylation status of SIRTs was studied by the methylation-sensitive digestion/real-time PCR method.

RESULTS

SIRT1 mRNA levels were lower in adipose tissues of obese patients than of normal-weight controls (VAT: P=0.0002, SAT: P=0.008). In contrast, expression of SIRT7 was higher in adipose tissues of obese patients than in the control group (VAT: P=0.001, SAT: P=0.008). The mean methylation of the SIRT1 and SIRT7 CpG islands was similar in tissues with high and low expression of these genes, and there was no correlation between the level of expression and the level of methylation. On the other hand, expression of SIRT1 in VAT of obese subjects correlated negatively with the expression of miR-22-3p (P<0.0001, r_s=-0.514), miR-34a-5p (P=0.01, r_s=-0.326) and miR-181a-3p (P<0.0001, r_s=-0.536). In turn, expression of SIRT7 in VAT of slim individuals correlated negatively with the expression of miR-125a-5p (P=0.003, r_s=-0.562) and miR-125b-5p (P=0.018, r_s=-0.460).

CONCLUSIONS

We observed obesity-associated downregulation of SIRT1 and upregulation of SIRT7 mRNA levels that were not associated with the methylation status of their promoters. We found a negative correlation between mRNA levels of SIRT1 in VAT of obese individuals and SIRT7 in VAT of the normal-weight subjects and expression of the relevant miRNAs.

miR-125b affects mitochondrial biogenesis and impairs brite adipocyte formation and function

Objective

In rodents and humans, besides brown adipose tissue (BAT), islands of thermogenic adipocytes, termed “brite” (brown-in-white) or beige adipocytes, emerge within white adipose tissue (WAT) after cold exposure or β3-adrenoceptor stimulation, which may protect from obesity and associated diseases. microRNAs are novel modulators of adipose tissue development and function. The purpose of this work was to characterize the role of microRNAs in the control of brite adipocyte formation.

Methods/Results

Using human multipotent adipose derived stem cells, we identified miR-125b-5p as downregulated upon brite adipocyte formation. In humans and rodents, miR-125b-5p expression was lower in BAT than in WAT. In vitro, overexpression and knockdown of miR-125b-5p decreased and increased mitochondrial biogenesis, respectively. In vivo, miR-125b-5p levels were downregulated in subcutaneous WAT and interscapular BAT upon β3-adrenergic receptor stimulation. Injections of an miR-125b-5p mimic and LNA inhibitor directly into WAT inhibited and increased β3-adrenoceptor-mediated induction of UCP1, respectively, and mitochondrial brite adipocyte marker expression and mitochondriogenesis.

Conclusion

Collectively, our results demonstrate that miR-125b-5p plays an important role in the repression of brite adipocyte function by modulating oxygen consumption and mitochondrial gene expression.

•

miR-125b-5p levels negatively correlate with UCP1 expression in rodent and human.

•

miR125b levels in white adipose tissue are positively correlated with BMI.

•

miR-125b-5p modulates oxygen consumption.

•

Mitochondriogenesis is controlled by miR-125b-5p.

•

In vivo modulation of miR-125b-5p controls brown and brite adipocyte formation.

MicroRNA regulatory networks in human adipose tissue and obesity

MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression and, therefore, biological processes in different tissues. A major function of miRNAs in adipose tissue is to stimulate or inhibit the differentiation of adipocytes, and to regulate specific metabolic and endocrine functions. Numerous miRNAs are present in human adipose tissue; however, the expression of only a few is altered in individuals with obesity and type 2 diabetes mellitus or are differentially expressed in various adipose depots. In humans, obesity is associated with chronic low-grade inflammation that is regulated by signal transduction networks, in which miRNAs, either directly or indirectly (through regulatory elements such as transcription factors), influence the expression and secretion of inflammatory proteins. In addition to their diverse effects on signalling, miRNAs and transcription factors can interact to amplify the inflammatory effect. Although additional miRNA signal networks in human adipose tissue are not yet known, similar regulatory circuits have been described in brown adipose tissue in mice. miRNAs can also be secreted from fat cells into the circulation and serve as markers of disturbed adipose tissue function. Given their role in regulating transcriptional networks, miRNAs in adipose tissue might offer tangible targets for treating metabolic disorders.

The complement system in human cardiometabolic disease

The complement system has been implicated in obesity, fatty liver, diabetes and cardiovascular disease (CVD). Complement factors are produced in adipose tissue and appear to be involved in adipose tissue metabolism and local inflammation. Thereby complement links adipose tissue inflammation to systemic metabolic derangements, such as low-grade inflammation, insulin resistance and dyslipidaemia. Furthermore, complement has been implicated in pathophysiological mechanisms of diet- and alcohol induced liver damage, hyperglycaemia, endothelial dysfunction, atherosclerosis and fibrinolysis. In this review, we summarize current evidence on the role of the complement system in several processes of human cardiometabolic disease. C3 is the central component in complement activation, and has most widely been studied in humans. C3 concentrations are associated with insulin resistance, liver dysfunction, risk of the metabolic syndrome, type 2 diabetes and CVD. C3 can be activated by the classical, the lectin and the alternative pathway of complement activation; and downstream activation of C3 activates the terminal pathway. Complement may also be activated via extrinsic proteases of the coagulation, fibrinolysis and the kinin systems. Studies on the different complement activation pathways in human cardiometabolic disease are limited, but available evidence suggests that they may have distinct roles in processes underlying cardiometabolic disease. The lectin pathway appeared beneficial in some studies on type 2 diabetes and CVD, while factors of the classical and the alternative pathway were related to unfavourable cardiometabolic traits. The terminal complement pathway was also implicated in insulin resistance and liver disease, and appears to have a prominent role in acute and advanced CVD. The available human data suggest a complex and potentially causal role for the complement system in human cardiometabolic disease. Further, preferably longitudinal studies are needed to disentangle which aspects of the complement system and complement activation affect the different processes in human cardiometabolic disease.

MicroRNAs: emerging roles in adipogenesis and obesity

Obesity is a serious health problem worldwide associated with an increased risk of life-threatening diseases such as type 2 diabetes, atherosclerosis, and certain types of cancer. Understanding the molecular basis of adipogenesis and fat cell development in obesity is essential to identify new biomarkers and therapeutic targets for the development of anti-obesity drugs. Recent computational and experimental studies have shown that microRNAs (miRNAs) appear to play regulatory roles in many biological processes associated with obesity, including adipocyte differentiation and lipid metabolism. In addition, many miRNAs are dysregulated in metabolic tissues from obese animals and humans, which potentially contributes to the pathogenesis of obesity-associated complications. The discovery of circulating miRNAs has highlighted their potential as both endocrine signaling molecules and disease markers. The potential of miRNA based therapeutics targeting obesity is highlighted as well as recommendations for future research which could lead to a breakthrough in the treatment of obesity.