MicroRNA-24 promotes 3T3-L1 adipocyte differentiation by directly targeting the MAPK7 signaling

Overexpression of LOX-1 in hepatocytes protects vascular smooth muscle cells from phenotype transformation and wire injury induced carotid neoatherosclerosis through ALOX15

Neoatherosclerosis (NA), the main pathological basis of late stent failure, is the main limitation of interventional therapy. However, the specific pathogenesis and treatment remain unclear. In vivo, NA model was established by carotid wire injury and high-fat feeding in ApoE-/- mice. Oxidized low-density lipoprotein receptor-1/lectin-like oxidized low-density lipoprotein receptor-1 (OLR1/LOX-1), a specific receptor for oxidized low-density lipoprotein (ox-LDL), was specifically ectopically overexpressed in hepatocytes by portal vein injection of adeno-associated serotype 8 (AAV8)-thyroid binding globulin (TBG)-Olr1 and the protective effect against NA was examined. In vitro, LOX-1 was overexpressed on HHL5 using lentivirus (LV)-OLR1 and the vascular smooth muscle cells (VSMCs)-HHL5 indirect co-culture system was established to examine its protective effect on VSMCs and the molecular mechanism. Functionally, we found that specific ectopic overexpression of LOX-1 by hepatocytes competitively engulfed and metabolized ox-LDL, alleviating its resulting phenotypic transformation of VSMCs including migration, downregulation of contractile shape markers (smooth muscle α-actin (SMαA) and smooth muscle-22α (SM22α)), and upregulation of proliferative/migratory shape markers (osteopontin (OPN) and Vimentin) as well as foaminess and apoptosis, thereby alleviating NA, which independent of low-density lipoprotein (LDL) lowering treatment (evolocumab, a monoclonal antibody to proprotein convertase subtilisin/kexin type 9 (PCSK9)). Mechanistically, we found that overexpression of LOX-1 in hepatocytes competitively engulfed and metabolized ox-LDL through upregulation of arachidonate-15-lipoxygenase (ALOX15), which further upregulated scavenger receptor class B type I (SRBI) and ATP-binding cassette transporter A1 (ABCA1). In conclusion, the overexpression of LOX-1 in liver protects VSMCs from phenotypic transformation and wire injury induced carotid neoatherosclerosis through ALOX15.

Integrative genomic analyses in adipocytes implicate DNA methylation in human obesity and diabetes

DNA methylation variations are prevalent in human obesity but evidence of a causative role in disease pathogenesis is limited. Here, we combine epigenome-wide association and integrative genomics to investigate the impact of adipocyte DNA methylation variations in human obesity. We discover extensive DNA methylation changes that are robustly associated with obesity (N = 190 samples, 691 loci in subcutaneous and 173 loci in visceral adipocytes, P < 1 × 10-7). We connect obesity-associated methylation variations to transcriptomic changes at >500 target genes, and identify putative methylation-transcription factor interactions. Through Mendelian Randomisation, we infer causal effects of methylation on obesity and obesity-induced metabolic disturbances at 59 independent loci. Targeted methylation sequencing, CRISPR-activation and gene silencing in adipocytes, further identifies regional methylation variations, underlying regulatory elements and novel cellular metabolic effects. Our results indicate DNA methylation is an important determinant of human obesity and its metabolic complications, and reveal mechanisms through which altered methylation may impact adipocyte functions.

Green tea actions on miRNAs expression – An update

Compounds derived from plants have been widely studied in the context of metabolic diseases and associated clinical conditions. In this regard, although the effects of Camellia sinensis plant, from which various types of teas, such as green tea, originate, have been vastly reported in the literature, the mechanisms underlying these effects remain elusive. A deep search of the literature showed that green tea's action in different cells, tissues, and diseases is an open field in the research of microRNAs (miRNAs). miRNAs are important communicator molecules between cells in different tissues implicated in diverse cellular pathways. They have emerged as an important linkage between physiology and pathophysiology, raising the issue of polyphenols can act also by changing miRNA expression. miRNAs are short, non-coding endogenous RNA, which silence the gene functions by targeting messenger RNA (mRNA) through degradation or translation repression. Therefore, the aim of this review is to present the studies that show the main compounds of green tea modulating the expression of miRNAs in inflammation, adipose tissue, skeletal muscle, and liver. We provide an overview of a few studies that have tried to demonstrate the role of miRNAs associated with the beneficial effects of compounds from green tea. We have emphasized that there is still a considerable gap in the literature investigating the role and likely involvement of miRNAs in the extensive beneficial health effects of green tea compounds already described, indicating miRNAs as potential polyphenols' mediators with a promising field to be investigated.

Identification of DDX5 as an indispensable activator of the glucocorticoid receptor in adipocyte differentiation

The expression of CCAAT/enhancer-binding protein (C/EBP) family members and peroxisome proliferator-activated receptor γ (PPAR γ) is essential for the differentiation of pre-adipocyte 3T3-L1 cells into mature adipocytes induced by a combined stimulation with dexamethasone, 3-isobutyl-1-methylxanthine and insulin (DMI). We herein demonstrated that the RNA helicase DDX5, the expression of which was induced by DMI, played an important role in the adipocyte differentiation of 3T3-L1 cells. The DMI-induced accumulation of lipid droplets and expression of adipocyte markers in 3T3-L1 cells were significantly inhibited by the knockdown of DDX5. The knockdown of DDX5 interfered with the expressional induction of C/EBPδ, which was the first to be induced in the transcription factor cascade, and inhibited the subsequent expression of the other transcription factors, C/EBPβ, PPARγ and C/EBPα. DDX5 interacted with the glucocorticoid receptor (GR), which induced the expression of C/EBPδ. The knockdown of DDX5 failed to induce the nuclear translocation of GR, suggesting the essential role of DDX5 in the early stage of adipocyte differentiation. Furthermore, the reconstitution of DDX5, but not the DDX5 mutant (K144N) lacking RNA helicase activity, restored DMI-induced GR activation and adipocyte differentiation in 3T3-L1 cells in which DDX5 was knocked down, confirming that the RNA helicase activity of DDX5 is essential for adipogenesis. Collectively, these results revealed for the first time that DDX5 is necessary for GR activation and plays an essential role in early adipocyte differentiation.

Bta-miR-6517 promotes proliferation and inhibits differentiation of pre-adipocytes by targeting PFKL

The proliferation and differentiation of pre-adipocytes are regulated by microRNAs (miRNAs) and other factors. In this study, the potential functions of bta-miR-6517 in the regulation of pre-adipocyte proliferation and differentiation were explored. The qRT-PCR, oil red O staining and CCK-8 assay were used to evaluate the role of bta-miR-6517. Further, the target gene of bta-miR-6517 was identified using bioinformatics analysis, dual-luciferase reporter system and qRT-PCR system. The results found that the overexpression of bta-miR-6517 promoted the expression of proliferation marker genes and substantially increased the adipocyte proliferation vitality in the CCK-8 assay, whereas suppressing of bta-miR-6517 had the opposite effect. Overexpression bta-miR-6517 suppressed the expression of adipogenic genes, which inhibited lipid accumulation, whereas suppressing of bta-miR-6517 had the opposite effect. Furthermore, the dual-fluorescent reporter experiment results demonstrated that bta-miR-6517 directly targeted phosphofructokinase, liver type (PFKL). When bta-miR-6517 was either overexpressed or suppressed, it negatively regulated PFKL. In conclusion, we observed that bta-miR-6517 promoted adipocyte proliferation and inhibited differentiation by targeting PFKL.

Genome-Wide Association Study for Haemonchus contortus Resistance in Morada Nova Sheep

Among the gastrointestinal nematodes affecting sheep, Haemonchus contortus is the most prevalent and virulent, resulting in health problems and production losses. Therefore, selecting sheep resistant to H. contortus is a suitable and sustainable strategy for controlling endoparasites in flocks. Here, 287 lambs of the native Brazilian Morada Nova hair sheep breed were subjected to two consecutive artificial infections with H. contortus and assessed for fecal egg count (FEC), packed cell volume (PCV), and live weight (LW). Forty-four animals ranked as having extreme resistance phenotypes were genotyped using the Illumina OvineSNP50v3 chip. A case−control genome-wide association study (GWAS) detected 37 significant (p < 0.001) markers in 12 ovine chromosomes in regions harboring quantitative trait loci (QTL) for FEC, Trichostrongylus spp. adults and larvae, weight, and fat; and candidate genes for immune responses, mucins, hematological parameters, homeostasis, and growth. Four single-nucleotide polymorphisms (SNP; OAR1_rs427671974, OAR2_rs419988472, OAR5_rs424070217, and OAR17_rs401006318) genotyped by qPCR followed by high-resolution melting (HRM) were associated with FEC and LW. Therefore, molecular markers detected by GWAS for H. contortus resistance in Morada Nova sheep may support animal selection programs aimed at controlling gastrointestinal nematode infections in flocks. Furthermore, genotyping of candidate genes using HRM qPCR may provide a rapid and efficient tool for animal identification.

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

Background

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

Methods

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

Results

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

Conclusion

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

Adipocyte differentiation between obese and lean conditions depends on changes in miRNA expression

Adipogenesis is the process by which precursor cells, preadipocytes (preACs), differentiate into adipocytes (ACs). Here, we investigated differentially expressed miRNAs (DEMs) between the two conditions to understand the regulatory role of miRNAs in altering adipogenesis-related mRNAs. A total of 812 and 748 DEMs were obtained in lean and obese conditions, respectively. The up- and downregulated DEMs were highly concordant with each other in both lean and obese conditions; however, DEMs related to adipogenesis in obese conditions were more strongly downregulated than DEMs related to adipogenesis in lean conditions. There were more obese-specific downregulated DEMs than lean-specific downregulated DEMs; in contrast, there were more lean-specific upregulated DEMs than obese-specific upregulated DEMs. Approximately 45% of DEMs were mapped to the list of miRNA-target mRNA pairs when DEMs were matched to the experimentally validated list of miRNA-target mRNA information of miRTarBase. Many of the target mRNAs were differentially expressed genes (DEGs) with functions in processes such as inflammatory responses and fat metabolism. In particular, a total of 25 miRNAs that target three upregulated adipogenesis-associated inflammatory genes (IL-6, TNF-α, and IL-1β) were commonly altered during adipogenesis. Taken together, our study reveals the types of adipogenesis-related miRNAs that are altered and the degree to which they influence healthy or pathogenic adipogenesis.

The miR-23-27-24 cluster: an emerging target in NAFLD pathogenesis

The incidence of non-alcoholic fatty liver disease (NAFLD) is increasing globally, being the most widespread form of chronic liver disease in the west. NAFLD includes a variety of disease states, the mildest being non-alcoholic fatty liver that gradually progresses to non-alcoholic steatohepatitis, fibrosis, cirrhosis, and eventually hepatocellular carcinoma. Small non-coding single-stranded microRNAs (miRNAs) regulate gene expression at the miRNA or translational level. Numerous miRNAs have been shown to promote NAFLD pathogenesis and progression through increasing lipid accumulation, oxidative stress, mitochondrial damage, and inflammation. The miR-23-27-24 clusters, composed of miR-23a-27a-24-2 and miR-23b-27b-24-1, have been implicated in various biological processes as well as many diseases. Herein, we review the current knowledge on miR-27, miR-24, and miR-23 in NAFLD pathogenesis and discuss their potential significance in NAFLD diagnosis and therapy.

Emerging Roles of Non-Coding RNAs in the Feed Efficiency of Livestock Species

A global population of already more than seven billion people has led to an increased demand for food and water, and especially the demand for meat. Moreover, the cost of feed used in animal production has also increased dramatically, which requires animal breeders to find alternatives to reduce feed consumption. Understanding the biology underlying feed efficiency (FE) allows for a better selection of feed-efficient animals. Non-coding RNAs (ncRNAs), especially micro RNAs (miRNAs) and long non-coding RNAs (lncRNAs), play important roles in the regulation of bio-logical processes and disease development. The functions of ncRNAs in the biology of FE have emerged as they participate in the regulation of many genes and pathways related to the major FE indicators, such as residual feed intake and feed conversion ratio. This review provides the state of the art studies related to the ncRNAs associated with FE in livestock species. The contribution of ncRNAs to FE in the liver, muscle, and adipose tissues were summarized. The research gap of the function of ncRNAs in key processes for improved FE, such as the nutrition, heat stress, and gut–brain axis, was examined. Finally, the potential uses of ncRNAs for the improvement of FE were discussed.

Mechanisms linking endoplasmic reticulum (ER) stress and microRNAs to adipose tissue dysfunction in obesity

Over accumulation of lipids in adipose tissue disrupts metabolic homeostasis by affecting cellular processes. Endoplasmic reticulum (ER) stress is one such process affected by obesity. Biochemical and physiological alterations in adipose tissue due to obesity interfere with adipose ER functions causing ER stress. This is in line with increased irregularities in other cellular processes such as inflammation and autophagy, affecting overall metabolic integrity within adipocytes. Additionally, microRNAs (miRNAs), which can post-transcriptionally regulate genes, are differentially modulated in obesity. A better understanding and identification of such miRNAs could be used as novel therapeutic targets to fight against diseases. In this review, we discuss ways in which ER stress participates as a common molecular process in the pathogenesis of obesity-associated metabolic disorders. Moreover, our review discusses detailed underlying mechanisms through which ER stress and miRNAs contribute to metabolic alteration in adipose tissue in obesity. Hence, identifying mechanistic involvement of miRNAs-ER stress cross-talk in regulating adipose function during obesity could be used as a potential therapeutic approach to combat chronic diseases, including obesity.

Recent Update on the Molecular Mechanisms of Gonadal Steroids Action in Adipose Tissue

The gonadal steroids, including androgens, estrogens and progestogens, are involved in the control of body fat distribution in humans. Nevertheless, not only the size and localization of the fat depots depend on the sex steroids levels, but they can also highly affect the functioning of adipose tissue. Namely, the gonadocorticoids can directly influence insulin signaling, lipid metabolism, fatty acid uptake and adipokine production. They may also alter energy balance and glucose homeostasis in adipocytes in an indirect way, e.g., by changing the expression level of aquaglyceroporins. This work presents the recent advances in understanding the molecular mechanism of how the gonadal steroids influence the functioning of adipose tissue leading to a set of detrimental metabolic consequences. Special attention is given here to highlighting the sexual dimorphism of adipocyte functioning in terms of health and disease. Particularly, we discuss the molecular background of metabolic disturbances occurring in consequence of hormonal imbalance which is characteristic of some common endocrinopathies such as the polycystic ovary syndrome. From this perspective, we highlight the potential drug targets and the active substances which can be used in personalized sex-specific management of metabolic diseases, in accord with the patient's hormonal status.

Identification of Molecular Mechanisms Related to Pig Fatness at the Transcriptome and miRNAome Levels

Fat deposition and growth rate are closely related to pork quality and fattening efficiency. The next-generation sequencing (NGS) approach for transcriptome and miRNAome massive parallel sequencing of adipocyte tissue was applied to search for a molecular network related to fat deposition in pigs. Pigs were represented by three breeds (Large White, Pietrain, and Hampshire) that varied in fat content within each breed. The obtained results allowed for the detection of significant enrichment of Gene Ontology (GO) terms and pathways associated directly and indirectly with fat deposition via regulation of fatty acid metabolism, fat cell differentiation, inflammatory response, and extracellular matrix (ECM) organization and disassembly. Moreover, the results showed that adipocyte tissue content strongly affected the expression of leptin and other genes related to a response to excessive feed intake. The findings indicated that modification of genes and miRNAs involved in ECM rearrangements can be essential during fat tissue growth and development in pigs. The identified molecular network within genes and miRNAs that were deregulated depending on the subcutaneous fat level are proposed as candidate factors determining adipogenesis, fatness, and selected fattening characteristics in pigs.

miR-196b-5p controls adipocyte differentiation and lipogenesis through regulating mTORC1 and TGF-β signaling

MicroRNAs have been reported to play a role in adipogenesis and obesity. This study was performed to investigate the role of miR-196b-5p in adipogenesis and the mechanism involved. The data revealed that miR-196b-5p expression increased in primary or established marrow stromal progenitor cells after adipogenic treatment. Supplementing miR-196b-5p in the progenitor cells stimulated adipogenic differentiation and lipogenesis, along with the induction of adipogenic and lipogenic factors. Conversely, inhibition of endogenous miR-196b-5p blocked adipogenesis and lipogenesis. Tuberous sclerosis 1 (Tsc1) and transforming growth factor-β receptor 1 (TGFBR1) were demonstrated to be the direct target genes of miR-196b-5p. Supplementing miR-196b-5p activity in progenitor cells reduced the protein level of TSC1 and activated mammalian target of rapamycin complex 1 (mTORC1) signaling. We further demonstrated that the perturbation of TSC1 in progenitor cells altered the trend of adipogenic differentiation and lipogenesis. Overexpression of Tsc1 or inactivation of mTORC1 signaling attenuated the stimulation of adipogenic differentiation and lipogenesis by miR-196b-5p. Overexpression of Tgfbr1 also partially blocked the adipogenic effect of miR-196b-5p. Further investigations demonstrated that zinc finger E-box-binding homeobox 1 (ZEB1) transcriptionally upregulated miR-196b-5p expression. The current study suggests that miR-196b-5p promotes adipogenic differentiation and lipogenesis in progenitor cells through targeting TSC1 and TGFBR1 and therefore regulating mTORC1 and TGF-β signaling.

The opposite functions of miR-24 in the osteogenesis and adipogenesis of adipose-derived mesenchymal stem cells are mediated by the HOXB7/β-catenin complex

Adipose-derived mesenchymal stem cells (ADMSCs) used in combination with nanoparticles or scaffolds represent promising candidates for bone engineering. Compared to bone marrow-derived MSCs (BMMSCs), ADMSCs show a relatively low capacity for osteogenesis. In the current study, miR-24 was identified as an osteogenesis- and adipogenesis-related miRNA that performs opposing roles (inhibition in osteogenesis and promotion in adipogenesis) during these two differentiation processes. Through bioinformatics analysis and luciferase reporter assays, homeobox protein Hox-B7 (HOXB7) was identified as a potential novel downstream target of miR-24 that contains a miR-24 binding site in the 3'-UTR of its mRNA. Overexpression of HOXB7 could partly halt the inhibitory effect of miR-24 on osteogenesis, and downregulation of HOXB7 could also partly suppress the positive effect of miR-24 on adipogenesis. Furthermore, immunoprecipitation experiments found that HOXB7 and β-catenin formed a functional complex that acted as an essential modulator during osteogenesis and adipogenesis of ADMSCs. After transfecting ADMSCs with an MSNs-PEI-miR-24 agomir or antagomir and loading the cells onto gelatin-chitosan scaffolds, the compounds were assessed for their abilities to repair the critical-sized calvarial defects in rats. Comprehensive evaluation, including micro-CT, sequential fluorescent labeling, and immunohistochemistry analysis, revealed that silencing miR-24 distinctly promoted in vivo bone remolding, whereas overexpression of miR-24 significantly repressed bone formation. Taken together, our findings demonstrated opposite roles for the miR-24/HOXB7/β-catenin signaling pathway in the osteogenesis and adipogenesis of ADMSCs, which may provide a novel mechanism for determining the balance between these two biological processes.

The preventive effect of phenolic-rich extracts from Chinese sumac fruits against nonalcoholic fatty liver disease in rats induced by a high-fat diet

The objective of this study is to investigate the preventive effect of phenolic-rich extracts from Chinese sumac (Rhus chinensis Mill.) fruits against NAFLD in rats induced by a high-fat diet and to clarify the underlying mechanisms.

microRNA-16-5p promotes 3T3-L1 adipocyte differentiation through regulating EPT1

Adipogenesis is an organized process of cellular differentiation by which pre-adipocytes differentiate towards mature adipocytes. miR-16-5p has been reported to be involved in cell proliferation, apoptosis, differentiation and angiogenesis. However little is known about miR-16-5p functional role in 3T3-L1 adipocyte differentiation. In this study, we found that miRNA-16-5p was significantly upregulated during 3T3-L1 preadipocytes differentiation towards mature adipocytes. Over-expression of miRNA-16-5p promoted mature adipocytes specific genes expression and fat droplet accumulation in vitro and in vivo. Meanwhile we have identified EPT1 as the target gene of miRNA-16-5p. Taken together, our data provided evidence to support that miRNA-16-5p promotes adipocyte differentiation by suppressing EPT1.

MicroRNAs and long noncoding RNAs: new regulators in cell fate determination of mesenchymal stem cells

Mesenchymal stem cells (MSCs) are multipotent cells that are able to differentiate into numerous cell types, including well-known inherent osteoblasts, adipocytes, and chondrocytes, and other cell types, such as hepatocytes, cardiomyocytes and nerve cells. They have become a favorite source of cell-based therapy. Therefore, knowing the mechanism that determines the cell fate of MSCs is important not only for deep understanding of the MSC function but also for the manipulation of MSCs for clinical application. Recently, studies have demonstrated that microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), the two best studied noncoding RNAs, show key roles in cell fate determination of MSCs by functioning as vital regulators of their target gene expression or signaling transduction. Here, we summarize the characteristics of miRNAs and lncRNAs, and review the recent advances proving their profound involvement in determining the cell fate of MSCs to inherent osteoblast, adipocyte, and chondrocyte cells, and to several key cell types including hepatocytes, cardiomyocytes and nerve cells. This will provide researchers with a deep understanding of the role of miRNAs and lncRNAs in MSCs and provide guidance for future research.

The recent advances of miRNAs and lncRNAs in determining the cell fate of MSCs.

miR-144-3p Promotes Adipogenesis Through Releasing C/EBPα From Klf3 and CtBP2

MicroRNAs (miRNAs), a class of small non-coding RNAs, have been proved as novel and potent regulators of adipogenesis. A previous study has found out that miR-144-3p was a biomarker of type 2 diabetes, but the role of miR-144-3p in regulating adipogenesis was still unclear. In the present study, the expression of miR-144-3p increased in obese mice and during the 3T3-L1 differentiation process. Overexpression of miR-144-3p suppressed the expression of cell cycle regulatory factors and inhibited pre-adipocytes proliferation. Besides, overexpression of miR-144-3p accelerated lipid accumulation in adipocytes and positively regulated adipogenesis, which was also accompanied by increasing the expression of genes related to fatty acid synthesis and decreasing the expression of genes involved in fatty acid oxidation. Furthermore, luciferase activity assays indicated that miR-144-3p directly targeted Klf3 and CtBP2. The process was also confirmed by the mRNA and protein expression of Klf3 and CtBP2, which were suppressed by miR-144-3p. Furthermore, miR-144-3p targeting Klf3/CtBP2 would induce C/EBPα activity by releasing corepressors (Klf3 and CtBP2) from its promoter region. Moreover, we also observed that miR-144-3p could promote adipogenesis in mice injected with miR-144-3p agomir through tail-vein injection. Taken together, these results support that miR-144-3p can facilitate adipogenesis both in vitro and in vivo, which implies that miR-144-3p could be a target for therapeutic intervention in obesity and metabolic syndrome in the future.

MicroRNA-143a-3p modulates preadipocyte proliferation and differentiation by targeting MAPK7

Adipogenesis plays a key role in increasing fat mass, which is a main characteristic for obesity, and involves preadipocyte proliferation and differentiation. Recently, more and more evidences suggested that microRNAs (miRNAs) is an important member of the regulatory network of adipogenesis. In this study, miR-143a-3p was highly expressed in adipose tissues of obese mice, and was up-regulated at the middle and last stage of 3T3-L1 adipocyte differentiation. Using mouse 3T3-L1 cells line, which is an ideal model in vitro for the study of adipogenesis, we observed that overexpression of miR-143a-3p inhibited the preadipocyte proliferation, and enhanced the preadipocyte differentiation. In contrast, the inhibition of miR-143a-3p expression promoted the preadipocyte proliferation, and inhibited the preadipocyte differentiation. Further analysis suggested that miR-143a-3p mediating preadipocyte differentiation might be involved in fatty acid metabolism. In addition, we found that miR-143-3p and PPARγ, an activator of miR-143a-3p transcription, could regulate each other. Compared with miR-143a-3p, MAPK7 played an opposite role in the proliferation and differentiation of adipocyte. Further analysis indicated that MAPK7 is a target gene of miR-143a-3p in 3T3-L1 cells, and inhibition of MAPK7 recede the effect of miR-143a-3p on preadipocyte proliferation and differentiation. Taken together, these results indicated that as a regulator of PPARγ, miR-143a-3p play an important role in adipogenesis via regulating MAPK7 and fatty acid.

Regulation of the MAPK signaling pathway by miR-421-5p in rats under light pollution

The present study aimed to explore the difference in the expression profiles of ovarian microRNA sequences in rats in a light pollution environment and rats in a normal light environment. Rats in the control group were exposed to 12‑h light/dark cycles, while rats in the model group were continuously exposed to 24‑h light. The ovaries were extracted from the two groups of rats, and Illumina HiSeq 2500 high‑throughput sequencing technology was used to detect the differences in microRNA (miRNA) expression among the two groups. Fluorescence quantitative reverse transcription‑polymerase chain reaction was used to verify the differential expression of miRNA. The present study was designed to experimentally validate the interaction between miR‑421‑5p and mitogen‑activated protein kinase (MAPK) 7 by using the dual‑luciferase reporter system, and to explore the expression of proteins in the MAPK signaling pathway with a lentiviral vector‑mediated small hairpin RNA interference against microRNA‑421‑5p. The expression of 45 miRNAs was significantly different. In total, 13 miRNAs were upregulated, of which 5 miRNA sequences were known and 8 were predicted. Furthermore, 32 miRNAs were downregulated, of which 11 miRNA sequences were known and 21 were predicted. The results of the luciferase reporter assay confirmed the targeting association between miR‑421‑5p and MAPK7. The expression levels of MAPK and genes in its downstream signaling pathways, including c‑Fos, CREB and c‑Myc, were downregulated when miR‑421‑5p was overexpressed and upregulated when miR‑421‑5p was silenced. The differential expression of miRNAs may serve an important role in the development of the ovary in a light pollution environment. miR‑421‑5p may regulate ovarian growth and development by targeting the MAPK signaling pathway in light polluted rat ovaries.

MiR-214 is an important regulator of the musculoskeletal metabolism and disease

MiR-214 belongs to a family of microRNA (small, highly conserved noncoding RNA molecules) precursors that play a pivotal role in biological functions, such as cellular function, tissue development, tissue homeostasis, and pathogenesis of diseases. Recently, miR-214 emerged as a critical regulator of musculoskeletal metabolism. Specifically, miR-214 can mediate skeletal muscle myogenesis and vascular smooth muscle cell proliferation, migration, and differentiation. MiR-214 also modulates osteoblast function by targeting specific molecular pathways and the expression of various osteoblast-related genes; promotes osteoclast activity by targeting phosphatase and tensin homolog (Pten); and mediates osteoclast-osteoblast intercellular crosstalk via an exosomal miRNA paracrine mechanism. Importantly, dysregulation in miR-214 expression is associated with pathological bone conditions such as osteoporosis, osteosarcoma, multiple myeloma, and osteolytic bone metastasis of breast cancer. This review discusses the cellular targets of miR-214 in bone, the molecular mechanisms governing the activities of miR-214 in the musculoskeletal system, and the putative role of miR-214 in skeletal diseases. Understanding the biology of miR-214 could potentially lead to the development of miR-214 as a possible biomarker and a therapeutic target for musculoskeletal diseases.

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

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

Comparison analysis of microRNAs in response to dengue virus type 2 infection between the Vero cell-adapted strain and its source, the clinical C6/36 isolated strain

To elucidate the differences in microRNAs during dengue virus infection between Vero cell-adapted strain (DENV-2-Vero) and its source, the clinical C6/36 isolated strain (DENV-2-C6/36), a comparison analysis was performed in Vero cells by high throughput sequencing. The results showed that the expression of 16 known and 3 novel miRNAs exhibited marked differences. 5 known miRNAs were up-regulated in DENV-2-C6/36 group, while 11 known microRNAs were down-regulated in DENV-2-Vero group. The GO enrichment and KEGG pathway analysis showed that there was a distinct difference in regulating viral replication between two strains. In DENV-2-Vero infection group, significantly enriched GO terms included virion attachment to host cells, viral structural protein/genome processing and packaging. Meanwhile, the regulation of cell death and apoptosis between two groups were different in the early stage of infection. KEGG enrichment analysis showed that DENV-2-C6/36 infection induced more intense regulation of immune-related pathways, including Fc gamma R-mediated phagocytosis, etc. DENV-2-Vero infection could partially alleviate the immune defense of Vero cells compared with DENV-2-C6/36. The results indicated that the distinct microRNA changes induced by two DENV-2 strains may be partly related to their infective abilities. Our data provide useful insights that help elucidate the host-pathogen interactions following DENV infection.

Shortcuts to a functional adipose tissue: The role of small non-coding RNAs

Metabolic diseases such as type 2 diabetes are a major public health issue worldwide. These diseases are often linked to a dysfunctional adipose tissue. Fat is a large, heterogenic, pleiotropic and rather complex tissue. It is found in virtually all cavities of the human body, shows unique plasticity among tissues, and harbors many cell types in addition to its main functional unit - the adipocyte. Adipose tissue function varies depending on the localization of the fat depot, the cell composition of the tissue and the energy status of the organism. While the white adipose tissue (WAT) serves as the main site for triglyceride storage and acts as an important endocrine organ, the brown adipose tissue (BAT) is responsible for thermogenesis. Beige adipocytes can also appear in WAT depots to sustain heat production upon certain conditions, and it is becoming clear that adipose tissue depots can switch phenotypes depending on cell autonomous and non-autonomous stimuli. To maintain such degree of plasticity and respond adequately to changes in the energy balance, three basic processes need to be properly functioning in the adipose tissue: i) adipogenesis and adipocyte turnover, ii) metabolism, and iii) signaling. Here we review the fundamental role of small non-coding RNAs (sncRNAs) in these processes, with focus on microRNAs, and demonstrate their importance in adipose tissue function and whole body metabolic control in mammals.