MiR-122 marks the differences between subcutaneous and visceral adipose tissues and associates with the outcome of bariatric surgery

Expression and Relations of Unique miRNAs Investigated in Metabolic Bariatric Surgery: A Systematic Review

Several studies have indicated that miRNAs play crucial roles in adipogenesis, insulin resistance, and inflammatory pathways associated with obesity and change after metabolic bariatric surgery (MBS). This systematic review explores and maps the existing literature on how miRNAs are expressed and investigates the unique miRNAs with the effects after MBS. The Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, and EMBASE were searched from 2019 until February 2024. This SR found 825 miRNAs from 25 studies, identifying 507 unique ones not used twice in the same study. A total of 21 studies (84%) measured RNA before and after surgery. The miRNA used per study ranged from 1 to 146 miRNA types, with a median study sample size of just 27 patients per study, raising concerns about some conclusions' robustness. From the 507 unique miRNAs, only 16 were consistently analyzed in 4 to 7 studies, which gave 77 different outcomes in relation to miRNA after MBS. MiRNA 122 and 122-5p were analyzed the most. Others were 106b-5p, 140-5p, 183-5p, 199b-5p, 20b-5p, 424-5p, 486-5p, 7-5p, 92a, 93-5p, 194-5p, 21-5p, 221, 320a, and 223-3p. A gap was observed in many studies, whereby the results were not the same, or there was no explanation for the effects after MBS was given within the same miRNA. Fifteen miRNAs were reported to have the same upward and downward trend, although not within the same study, and only 26.1% employed some form of statistical modeling to account for bias or confounding factors. Directions and effects in miRNA are visible, but still, inconsistent outcomes linked to the same miRNA after MBS, underscoring the need for clarity in miRNA-outcome relationships. Collaborative efforts, consensus-driven miRNA dictionaries, and larger, more rigorous studies are necessary to improve methodology designs and improve outcomes.

Towards an adiposity-related disease framework for the diagnosis and management of obesities

Obesity is a complex disease that relapses frequently and associates with multiple complications that comprise a worldwide health priority because of its rising prevalence and association with numerous complications, including metabolic disorders, mechanic pathologies, and cancer, among others. Noteworthy, excess adiposity is accompanied by chronic inflammation, oxidative stress, insulin resistance, and subsequent organ dysfunction. This dysfunctional adipose tissue is initially stored in the visceral depot, overflowing subsequently to produce lipotoxicity in ectopic depots like liver, heart, muscle, and pancreas, among others. People living with obesity need a diagnostic approach that considers an exhaustive pathophysiology and complications assessment. Thus, it is essential to warrant a holistic diagnosis and management that guarantees an adequate health status, and quality of life. The present review summarizes the different complications associated with obesity, at the same time, we aim to fostering a novel framework that enhances a patient-centered approach to obesity management in the precision medicine era.

Change Profiles and Functional Targets of MicroRNAs in Type 2 Diabetes Mellitus Patients with Obesity

BACKGRUOUND

MicroRNAs (miRNAs) exert an essential contribution to obesity and type 2 diabetes mellitus (T2DM). This study aimed to investigate the differences of miRNAs in the presence and absence of T2DM in patients with obesity, as well as before and after bariatric surgery in T2DM patients with obesity. Characterization of the common changes in both was further analyzed.

METHODS

We enrolled 15 patients with obesity but without T2DM and 15 patients with both obesity and T2DM. Their preoperative clinical data and serum samples were collected, as well as 1 month after bariatric surgery. The serum samples were analyzed by miRNA sequencing, and the miRNAs profiles and target genes characteristics were compared.

RESULTS

Patients with T2DM had 16 up-regulated and 32 down-regulated miRNAs compared to patients without T2DM. Improvement in metabolic metrics after bariatric surgery of T2DM patients with obesity was correlated with changes in miRNAs, as evidenced by the upregulation of 20 miRNAs and the downregulation of 30 miRNAs. Analysis of the two miRNAs profiles identified seven intersecting miRNAs that showed opposite changes. The target genes of these seven miRNAs were substantially enriched in terms or pathways associated with T2DM.

CONCLUSION

We determined the expression profiles of miRNAs in the obese population, with and without diabetes, before and after bariatric surgery. The miRNAs that intersected in the two comparisons were discovered. Both the miRNAs discovered and their target genes were closely associated with T2DM, demonstrating that they might be potential targets for the regulation of T2DM.

The Lnc-HOTAIR/miR122/PPARγ signaling mediated the occurrence and continuous development of alcohol-induced Osteonecrosis of the femoral head

This study aimed to explore the mechanism of alcohol-induced Osteonecrosis of the femoral head (ONFH) through in vivo and in vitro experiments. In vitro, the Oil Red O staining showed that ethanol promoted extracellular adipogenesis in a dose-dependent manner. ALP staining and alizarin red staining showed that ethanol inhibited the formation of extracellular mineralization in a dose-dependent manner. The Oil Red O staining showed that miR122 mimics and Lnc-HOTAIR SiRNA rescued extracellular adipogenesis induced by ethanol in BMSCs. Besides, we found that the high expression of PPARγ in BMSCs recruited histone deacetylase 3 (HDAC3) and histone methyltransferase (SUV39H1), which reduced the histone acetylation level and increased the histone methylation level in the miR122 promoter region, respectively. In vivo, the levels of H3K9ac, H3K14ac, and H3K27ac of miR122 promoter region in the ethanol group were significantly decreased compared to the control group, respectively. The levels of H3K9me2 and H3K9me3 of miR122 promoter region in the ethanol group were significantly increased compared to the control group. Lnc-HOTAIR/miR-122/PPARγ signaling mediated the alcohol-induced ONFH in the rat model. Furthermore, the persistent decrease of miR122 expression mediated the continuous progress of alcohol-induced ONFH after stopping alcohol consumption.

Molecular, Metabolic, and Nutritional Changes after Metabolic Surgery in Obese Diabetic Patients (MoMen): A Protocol for a Multicenter Prospective Cohort Study

Metabolic surgery is an essential option in the treatment of obese patients with type 2 diabetes (T2D). Despite its known advantages, this surgery still needs to be introduced in Malaysia. In this prospective study, the pathophysiological mechanisms at the molecular level will be studied and the metabolomics pathways of diabetes remission will be explored. The present study aims to evaluate the changes in the anthropometric measurements, body composition, phase angle, diet intake, biochemistry parameters, adipokines, microRNA, and metabolomics, both pre- and post-surgery, among obese diabetic patients in Malaysia. This is a multicenter prospective cohort study that will involve obese patients (n = 102) with a body mass index (BMI) of ≥25 kg/m2 (Asian BMI categories: WHO/IASO/IOTF, 2000) who will undergo metabolic surgery. They will be categorized into three groups: non-diabetes, prediabetes, and diabetes. Their body composition will be measured using a bioimpedance analyzer (BIA). The phase angle (PhA) data will be analyzed. Venous blood will be collected from each patient for glycated hemoglobin (HbA1c), lipids, liver, renal profile, hormones, adipokines, and molecular and metabolomics analyses. The serum microRNA will be measured. A gene expression study of the adipose tissue of different groups will be conducted to compare the groups. The relationship between the 1HNMR-metabolic fingerprint and the patients’ lifestyles and dietary practices will be determined. The factors responsible for the excellent remission of T2D will be explored in this study.

Integrated analysis of expression profiles with meat quality traits in cattle

MicroRNAs (miRNAs) play a vital role in improving meat quality by binding to messenger RNAs (mRNAs). We performed an integrated analysis of miRNA and mRNA expression profiling between bulls and steers based on the differences in meat quality traits. Fat and fatty acids are the major phenotypic indices of meat quality traits to estimate between-group variance. In the present study, 90 differentially expressed mRNAs (DEGs) and 18 differentially expressed miRNAs (DEMs) were identified. Eighty-three potential DEG targets and 18 DEMs were used to structure a negative interaction network, and 75 matching target genes were shown in this network. Twenty-six target genes were designated as intersection genes, screened from 18 DEMs, and overlapped with the DEGs. Seventeen of these genes enriched to 19 terms involved in lipid metabolism. Subsequently, 13 DEGs and nine DEMs were validated using quantitative real-time PCR, and seven critical genes were selected to explore the influence of fat and fatty acids through hub genes and predict functional association. A dual-luciferase reporter and Western blot assays confirmed a predicted miRNA target (bta-miR-409a and PLIN5). These findings provide substantial evidence for molecular genetic controls and interaction among genes in cattle.

Extracellular miRNAs as mediators of obesity-associated disease

Extracellular miRNAs are found in a variety of body fluids and mediate intercellular and interorgan communication, thus regulating gene expression and cellular metabolism. These miRNAs are secreted either in small vesicles/exosomes (sEV) or bound to proteins such as Argonaute and high-density lipoprotein. Both exosomal and protein-bound circulating miRNAs are altered in obesity. Although all tissues can contribute to changes in circulating miRNAs, adipose tissue itself is an important source of these miRNAs, especially those in sEVs. These are derived from both adipocytes and macrophages and participate in crosstalk between these cells, as well as peripheral tissues, including liver, skeletal muscle and pancreas, whose function may be impaired in obesity. Changes in levels of circulating miRNAs have also been linked to the beneficial effects induced by weight loss interventions, including diet, exercise and bariatric surgery, further indicating a role for these miRNAs as mediators of disease pathogenesis. Here, we review the role of circulating miRNAs in the pathophysiology of obesity and explore their potential use as biomarkers and in therapy of obesity-associated metabolic syndrome.

Exosomal miR-122 promotes adipogenesis and aggravates obesity through the VDR/SREBF1 axis

OBJECTIVE

This study examined the effects of miR-122-enriched exosomes on the expression of vitamin D3 receptor (VDR) and sterol regulatory element-binding transcription factor 1 (SREBF1) and their roles during adipogenesis.

METHODS

The roles of miR-122, SREBF1, and VDR were investigated during adipogenesis. The relationships between VDR and miR-122 or SREBF1 were assessed by dual-luciferase reporter and chromatin immunoprecipitation assays. The potential role of miR-122/VDR/SREBF1 was evaluated in high-fat diet-induced obese male mice.

RESULTS

High levels of miR-122 were found only in adipose tissue-derived exosomes (Exo-AT) and Exo-AT-treated cells. Overexpression of miR-122 promoted adipogenesis, and inhibition of miR-122 prevented adipogenesis by regulating VDR, SREBF1, peroxisome proliferator-activated receptor gamma, lipoprotein lipase, and adiponectin. Knockdown of Srebf1 or overexpression of VDR could inhibit adipogenesis. However, exosomal miR-122 could reverse their inhibitory effects. The dual-luciferase reporter assay and chromatin immunoprecipitation assays confirmed that VDR was a direct target of miR-122. It could bind to the BS1 region of the SREBF1 promoter and inhibit SREBF1 expression. Moreover, miR-122 inhibition could alleviate obesity in high-fat diet-induced obese male mice, possibly through upregulating the VDR/SREBF1 axis.

CONCLUSION

MiR-122-enriched Exo-AT promoted adipogenesis by regulating the VDR/SREBF1 axis.

Serum microRNA panels predict bariatric surgery outcomes

OBJECTIVE

The weight losses after bariatric surgery are modulated by multiple factors in people with obesity. MicroRNAs (miRNAs) have been reported to show significant regulatory roles in adipose tissue. However, a serum miRNA signature to serve as a biomarker of sustained weight losses following bariatric surgery has not yet been established.

METHODS

MiRNA microarray was used to identify differentially expressed miRNAs in the serum of patients with an effective response after bariatric surgery compared with those without. Excess weight loss > 55% at 6 months after surgery was defined as an effective response.

RESULTS

Three miRNAs were shown to have a significantly differential expression between patients with or without an effective response following bariatric surgery. The miR-31-5p was downregulated, whereas miR-328-3p and miR-181a-5p were upregulated in the patients with effective responses compared with those without effective responses. Panels of the serum ratios of miR-328-3p/miR-31-5p or miR-181a-5p/miR-31-5p and individual BMI value exhibited good performance in preoperative prediction of treatment effectiveness. Bioinformatic analysis depicted that predicted targets of these miRNAs were involved in the regulation of the AMP-activated protein kinase signaling pathway.

CONCLUSIONS

A circulating miRNA signature with clinical variables (BMI) can be a clinical biomarker to predict effectiveness following bariatric surgery.

Epigenomics analysis of miRNA cis-regulatory elements in pig muscle and fat tissues

Although large-scale and accurate identification of cis-regulatory elements on pig protein-coding and long non-coding genes has been reported, similar study on pig miRNAs is still lacking. Here, we systematically characterized the cis-regulatory elements of pig miRNAs in muscle and fat by adopting miRNAomes, ChIP-seq, ATAC-seq, RNA-seq and Hi-C data. In total, the cis-regulatory elements of 257 (85.95%) expressed miRNAs including 226 known and 31 novel miRNAs were identified. Especially, the miRNAs associated with super-enhancers, active promoters, and "A" compartment were significantly higher than those associated by typical enhancers, prompters without H3K27ac, and "B" compartment, respectively. The tissue specific transcription factors were the primary determination of core miRNA expression pattern in muscle and fat. Moreover, the miRNA promoters are more evolutionarily conserved than miRNA enhancers, like other type genes. Our study adds additional important information to existing pig epigenetic data and provides essential resource for future in-depth investigation of pig epigenetics.

Hepatic microRNA modulation might be an early event to non-alcoholic fatty liver disease development driven by high-fat diet in male mice

INTRODUCTION

Metabolic alterations caused by an imbalance of macronutrient consumption are often related to the modulation of microRNAs (miRNAs), which could alter mRNAs expression profile and accelerate the development of non-alcoholic fatty liver disease (NAFLD).

AIMS

This study aimed to investigate the contribution of miRNAs in modulating early stages of NAFLD in mice submitted to a high-fat diet (HFD).

METHODS AND RESULTS

Male Swiss mice, fed either a control diet or an HFD for 1, 3, 7, 15, 30, 56 days, were assessed for metabolic alterations, gene expression and NAFLD markers. A hepatocyte cell line was used to investigate the effects of miR-370 modulation on enzymes involved in β-oxidation. Body weight and adiposity were higher after 7 days of HFD. Fasting glucose and insulin increased after 3 and 7 days of HFD, respectively. While hepatic lipid content increased from the first day on, hepatic glycogen had a decrease after 3 days of HFD consumption. miR-370 and Let-7 expression increased with acute and chronic exposure to HFD, accompanied by carnitine palmitoyltransferase 1A (Cpt1a), acyl-CoA dehydrogenase very long chain (Acadvl) and protein kinase AMP-activated Catalytic Subunit 2 (Prkaa2) downregulation, while decreased miR-122 expression was accompanied by 1-acylglycerol-3-phosphate-O-acyltransferase (Agpat) upregulation after 56 days of HFD consumption, some of them confirmed by in vitro experiments. Despite fluctuations in TNFa and IL6 mRNA levels, molecular modulation was consistent with hepatic TG and NAFLD development.

CONCLUSION

Hepatic miR-370-122-Let7 miRNA modulation could be the first insult to NAFLD development, preceding changes in glycemic homeostasis and adiposity.

Assessing Obesity-Related Adipose Tissue Disease (OrAD) to Improve Precision Medicine for Patients Living With Obesity

Obesity is a heterogenous condition that affects the life and health of patients to different degrees and in different ways. Yet, most approaches to treat obesity are not currently prescribed, at least in a systematic manner, based on individual obesity sub-phenotypes or specifically-predicted health risks. Adipose tissue is one of the most evidently affected tissues in obesity. The degree of adipose tissue changes - "adiposopathy", or as we propose to relate to herein as Obesity-related Adipose tissue Disease (OrAD), correspond, at least cross-sectionally, to the extent of obesity-related complications inflicted on an individual patient. This potentially provides an opportunity to better personalize anti-obesity management by utilizing the information that can be retrieved by assessing OrAD. This review article will summarize current knowledge on histopathological OrAD features which, beyond cross-sectional analyses, had been shown to predict future obesity-related endpoints and/or the response to specific anti-obesity interventions. In particular, the review explores adipocyte cell size, adipose tissue inflammation, and fibrosis. Rather than highly-specialized methods, we emphasize standard pathology laboratory approaches to assess OrAD, which are readily-available in most clinical settings. We then discuss how OrAD assessment can be streamlined in the obesity/weight-management clinic. We propose that current studies provide sufficient evidence to inspire concerted efforts to better explore the possibility of predicting obesity related clinical endpoints and response to interventions by histological OrAD assessment, in the quest to improve precision medicine in obesity.

Obesity and Roux-en-Y gastric bypass drive changes in miR-31 and miR-215 expression in the human rectal mucosa

Background/Objectives

Obesity increases colorectal cancer (CRC) risk. However, the effects of weight loss on CRC risk are unclear. Epigenetic mechanisms involving microRNAs that lead to dysregulated gene expression may mediate the effects of obesity and weight loss on CRC risk. We examined the effects of obesity and weight loss following Roux-en-Y gastric bypass (RYGB) on microRNA expression in the human rectal mucosa.

Subjects/Methods

We collected rectal mucosal biopsies from obese patients (n = 22) listed for RYGB and age- and sex-matched healthy non-obese Controls (n = 20), at baseline and six months post-surgery. We quantified microRNA expression in rectal mucosal biopsies using Next Generation Sequencing and bioinformatics analysis to investigate the likely functional consequences of these epigenetic changes.

Results

Compared with non-obese individuals, obese individuals showed differential expression of 112 microRNAs (p < 0.05). At six-months post-RYGB, when mean body mass had fallen by 27 kg, 60 microRNAs were differentially expressed, compared with baseline (p < 0.05). The expression of 36 microRNAs differed significantly between both i) obese and non-obese individuals and ii) obese individuals pre- and post-RYGB. Quantitative polymerase chain reaction (qPCR) demonstrated that expression of miR-31 and miR-215 was significantly (p < 0.05) higher, 143-fold and 15-fold respectively, in obese than in non-obese individuals. Weight loss, following RYGB, reduced expression of miR-31 and miR-215 to levels comparable with Controls. These differentially expressed microRNAs are implicated in pathways linked with inflammation, obesity and cancer.

Conclusion

Our findings show, for the first time, that obesity is associated with dysregulated microRNA expression in the human rectal mucosa. Further, surgically-induced weight loss may normalise microRNA expression in this tissue.

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

BACKGROUND

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

AIM

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

RESULTS

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

CONCLUSIONS

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

Visceral-to-subcutaneous fat ratio independently predicts the prognosis of locally advanced gastric cancer----- highlighting the role of adiponectin receptors and PPARα, β/ δ, ɤ

BACKGROUND

Results of computed tomography body composition (CTBC) predicting long-term outcomes of gastric cancer have been mixed and the plausible mechanism remains elusive.

METHODS

We retrospectively enrolled a cohort of stage III gastric cancer who had undergone curative-intent gastrectomy. Clinicopathological variables, preoperative CTBC including abdominal muscle, subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT), and nutritional and inflammatory index were taken together to construct prognostic analysis. In vitro tests using co-culture system of gastric cancer cell lines and visceral adipocytes were conducted.

RESULTS

A total of 191 eligible patients were enrolled. By multivariate analysis, SAT and VAT/ SAT ratio were prognostic factors of disease-free survival, while sarcopenia was not. SAT remained as a prognostic factor of overall survival. SAT index was positively correlated with prognostic nutritional index, while VAT HU was positively correlated with platelet-to-lymphocyte ratio. Expression of adiponectin receptor 1 and 2 (AdipoR1, R2), and peroxisome proliferator-activated receptor (PPAR) α, β/δ, ɤ of patients with higher VAT/SAT ratio were decreased as compared to those with lower VAT/SAT ratio. Proliferation of gastric cancer cells co-cultured with adipocytes was increased by 50-100% and accompanied by down-regulation of mRNAs of AdipoR1, 2, PPARα, β/δ, ɤ, and pro-apoptotic genes, as compared to their controls.

CONCLUSION

SAT and VAT played exactly opposite prognostic roles of locally advanced gastric cancers, which might work through modulation of AdipoR1, 2 and PPARα, β/δ, ɤ. Preoperative CTBC, supplementary to classic TNM system, helps clinicians tailor individualized adjuvant therapy and/or nutritional support.

Use of Molecular Methods to Authenticate Animal Species and Tissue in Bovine Liver Dietary Supplements

Dietary supplements containing bovine (subfamily Bovinae) liver are susceptible to fraud due to their high value and the lack of modern detection methods available for processed animal tissues. The objective of this research was to use molecular methods to authenticate dietary supplements claiming to contain bovine liver or beef liver through the verification of animal species and tissue type. A total of 53 bovine/beef liver dietary supplements were purchased from online sources. The presence of liver was verified with reverse transcription and real-time PCR testing for microRNA-122 (miR-122), which is highly expressed in liver tissue. Multiplex real-time PCR targeting domestic cattle (Bos taurus), horse (Equus caballus), sheep (Ovis aries), and pork (Sus scrofa) was used to verify species. Samples that failed species identification with multiplex real-time PCR underwent DNA mini-barcoding. Overall, bovine species were detected in 48/53 liver supplements: 35 samples were confirmed as domestic cattle with multiplex real-time PCR and an additional 13 samples were confirmed as domestic cattle or Bos spp. with DNA mini-barcoding. One of these samples was also positive for sheep/lamb, which was declared on the label. One product contained undeclared pork in addition to beef. MiR-122 was detected in 51 out of 53 supplements, suggesting the presence of liver. While this study demonstrates the potential use of tissue-specific microRNAs in verifying tissues in dietary supplements, more research is needed to evaluate the specificity of these markers.

Roles of MicroRNA-122 in Cardiovascular Fibrosis and Related Diseases

Fibrotic diseases cause annually more than 800,000 deaths worldwide, where of the majority accounts for cardiovascular fibrosis, which is characterized by endothelial dysfunction, myocardial stiffening and reduced dispensability. MicroRNAs (miRs), small noncoding RNAs, play critical roles in cardiovascular dysfunction and related disorders. Intriguingly, there is a critical link among miR-122, cardiovascular fibrosis, sirtuin 6 (SIRT6) and angiotensin-converting enzyme 2 (ACE2), which was recently identified as a coreceptor for SARS-CoV2 and a negative regulator of the rennin-angiotensin system. MiR-122 overexpression appears to exacerbate the angiotensin II-mediated loss of autophagy and increased inflammation, apoptosis, extracellular matrix deposition, cardiovascular fibrosis and dysfunction by modulating the SIRT6-Elabela-ACE2, LGR4-β-catenin, TGFβ-CTGF and PTEN-PI3K-Akt signaling pathways. More importantly, the inhibition of miR-122 has proautophagic, antioxidant, anti-inflammatory, anti-apoptotic and antifibrotic effects. Clinical and experimental studies clearly demonstrate that miR-122 functions as a crucial hallmark of fibrogenesis, cardiovascular injury and dysfunction. Additionally, the miR-122 level is related to the severity of hypertension, atherosclerosis, atrial fibrillation, acute myocardial infarction and heart failure, and miR-122 expression is a risk factor for these diseases. The miR-122 level has emerged as an early-warning biomarker cardiovascular fibrosis, and targeting miR-122 is a novel therapeutic approach against progression of cardiovascular dysfunction. Therefore, an increased understanding of the cardiovascular roles of miR-122 will help the development of effective interventions. This review summarizes the biogenesis of miR-122; regulatory effects and underlying mechanisms of miR-122 on cardiovascular fibrosis and related diseases; and its function as a potential specific biomarker for cardiovascular dysfunction.

MicroRNAs and their regulatory networks in Chinese Gushi chicken abdominal adipose tissue during postnatal late development

Background

Abdominal fat is the major adipose tissue in chickens. The growth status of abdominal fat during postnatal late development ultimately affects meat yield and quality in chickens. MicroRNAs (miRNAs) are endogenous small noncoding RNAs that regulate gene expression at the post-transcriptional level. Studies have shown that miRNAs play an important role in the biological processes involved in adipose tissue development. However, few studies have investigated miRNA expression profiles and their interaction networks associated with the postnatal late development of abdominal adipose tissue in chickens.

Results

We constructed four small RNA libraries from abdominal adipose tissue obtained from Chinese domestic Gushi chickens at 6, 14, 22, and 30 weeks. A total of 507 known miRNAs and 53 novel miRNAs were identified based on the four small RNA libraries. Fifty-one significant differentially expressed (SDE) miRNAs were identified from six combinations by comparative analysis, and the expression patterns of these SDE miRNAs were divided into six subclusters by cluster analysis. Gene ontology enrichment analysis showed that the SDE miRNAs were primarily involved in the regulation of fat cell differentiation, regulation of lipid metabolism, regulation of fatty acid metabolism, and unsaturated fatty acid metabolism in the lipid metabolism- or deposition-related biological process categories. In addition, we constructed differentially expressed miRNA–mRNA interaction networks related to abdominal adipose development. The results showed that miRNA families, such as mir-30, mir-34, mir-199, mir-8, and mir-146, may have key roles in lipid metabolism, adipocyte proliferation and differentiation, and cell junctions during abdominal adipose tissue development in chickens.

Conclusions

This study determined the dynamic miRNA transcriptome and characterized the miRNA–mRNA interaction networks in Gushi chicken abdominal adipose tissue for the first time. The results expanded the number of known miRNAs in abdominal adipose tissue and provide novel insights and a valuable resource to elucidate post-transcriptional regulation mechanisms during postnatal late development of abdominal adipose tissue in chicken.

Exosomal microRNA-122 mediates obesity-related cardiomyopathy through suppressing mitochondrial ADP-ribosylation factor-like 2

Emerging studies have demonstrated that microRNAs (miRs) participate in the development of multiple metabolic complications including cardiovascular diseases. Among them, circulating level of liver-secreted miR-122 was closely correlated with several consequence of heart diseases in clinical studies, and overexpression of miR-122 impaired cardiomyocyte function. However, it was unknown whether miR-122 could regulate cardiac biology in obesity. Therefore, present study was to disclose the role of miR-122 in cardiac metabolic disorders and potential molecular mechanisms. Through utilizing clinical samples and high fat diet-fed mice, we investigated the physiological roles of miR-122 in obesity-related cardiomyopathy. Besides, present study explored the mitochondrial function under exosomal miR-122 stimulation in mouse primary cardiomyocytes. In clinical samples and obese mice, the circulating level of exosomal miR-122 was positively correlated with cardiac dysfunctional parameters, including reduction in ejection fraction (EF) and increased levels of NT-proBNP. Human plasma exosomes transported miR-122 into mouse primary cardiomyocytes, and impaired mitochondrial ATP production and oxygen consumption, whereas miR-122 sponge improved these inhibitory effects. In dietary-induced mice, increased hepatic and circulating exosomal miR-122 deteriorated cardiac structure and functional index, and inhibited mitochondrial function. Liver-specific blockage of miR-122 attenuated abnormal cardiac remodeling. Mechanistically, miR-122 directly bound and suppressed mitochondrial protein ADP-ribosylation factor-like 2 (Arl-2) in vitro and in vivo Knockdown of Arl-2 abolished the mitochondrial benefits of miR-122 sponge in exosome-treated mouse primary cardiomyocytes.In conclusions, our present study firstly showed that liver-secreted exosomal miR-122 played a critical role in the development of metabolic cardiomyopathy, and miR-122/mitochondrial Arl-2 signaling affected cardiac energy homeostasis.

High Fructose Intake and Adipogenesis

In modern societies, high fructose intake from sugar-sweetened beverages has contributed to obesity development. In the diet, sucrose and high fructose corn syrup are the main sources of fructose and can be metabolized in the intestine and transported into the systemic circulation. The liver can metabolize around 70% of fructose intake, while the remaining is metabolized by other tissues. Several tissues including adipose tissue express the main fructose transporter GLUT5. In vivo, chronic fructose intake promotes white adipose tissue accumulation through activating adipogenesis. In vitro experiments have also demonstrated that fructose alone induces adipogenesis by several mechanisms, including (1) triglycerides and very-low-density lipoprotein (VLDL) production by fructose metabolism, (2) the stimulation of glucocorticoid activation by increasing 11β-HSD1 activity, and (3) the promotion of reactive oxygen species (ROS) production through uric acid, NOX and XOR expression, mTORC1 signaling and Ang II induction. Moreover, it has been observed that fructose induces adipogenesis through increased ACE2 expression, which promotes high Ang-(1-7) levels, and through the inhibition of the thermogenic program by regulating Sirt1 and UCP1. Finally, microRNAs may also be involved in regulating adipogenesis in high fructose intake conditions. In this paper, we propose further directions for research in fructose participation in adipogenesis.

Differential expression of mRNA-miRNAs related to intramuscular fat content in the longissimus dorsi in Xinjiang brown cattle

In this study, we examined the role of mRNAs and miRNAs in variations in intramuscular fat content in the longissimus dorsi muscle in Xinjiang brown cattle. Two groups of Xinjiang brown cattle with extremely different intramuscular fat content in the longissimus dorsi were selected for combined of miRNA and mRNA analysis using an RNA-Seq. In total, 296 mRNAs and 362 miRNAs were significantly differentially expressed, including 155 newly predicted miRNAs, 275 significantly upregulated genes, 252 significantly upregulated miRNAs, 21 significantly downregulated genes and 110 significantly downregulated miRNAs. The combined miRNA and mRNA analysis identified 96 differentially expressed miRNAs and 27 differentially expressed mRNAs. In all, 47 upregulated miRNAs had a regulatory effect on 14 differentially downregulated target genes, and 49 downregulated miRNAs had a regulatory effect on 13 upregulated target genes. To verify the sequencing results, 10 differentially expressed genes (DEGs) and 10 differentially expressed miRNAs were selected for qRT-PCR. The qRT-PCR results confirmed the sequencing results. The results of this study shed light on the molecular regulation of bovine adipose tissue, which might help with the development of new strategies for improving meat quality and animal productivity in beef cattle to provide healthier meat products for consumers.