MiRNA-181a regulates adipogenesis by targeting tumor necrosis factor-α (TNF-α) in the porcine model

Non-Coding RNAs in Regulating Fat Deposition in Farm Animals

Fat deposition represents a crucial feature in the expenditure of physical energy and affects the meat quality of farm animals. It is regulated by multiple genes and regulators. Of them, non-coding RNAs (ncRNAs) play a critical role in modulating the fat deposition process. As well as being an important protein source, farm animals can be used as medical models, so many researchers worldwide have explored their mechanism of fat deposition. This article summarizes the transcription factors, regulatory genes, and signaling pathways involved in the molecular regulation process of fat deposition; outlines the progress of researching the roles of microRNAs (miRNAs), long ncRNAs (lncRNAs), and circular RNAs (circRNAs) in fat deposition in common farm animals including pigs, cattle, sheep, ducks, and chickens; and identifies scientific problems in the field that must be further investigated. It has been demonstrated that ncRNAs play a critical role in regulating the fat deposition process and have great potential in improving meat quality traits.

The Interplay Between Obesity and Aging in Breast Cancer and Regulatory Function of MicroRNAs in This Pathway

Breast cancer (BC) is a significant contributor to cancer-related deaths in women, and it has complex connections with obesity and aging. This review explores the interaction between obesity and aging in relation to the development and progression of BC, focusing on the controlling role of microRNAs (miRNAs). Obesity, characterized by excess adipose tissue, contributes to a proinflammatory environment and metabolic dysregulation, which are important in tumor development. Aging, associated with cellular senescence and systemic changes, further exacerbates these conditions. miRNAs, small noncoding RNAs that regulate gene expression, play key roles in these processes, impacting pathways involved in cell proliferation, apoptosis, and cancer metastasis, either as tumor suppressors or oncogenes. Importantly, specific miRNAs are implicated in mediating the impact of obesity and aging on BC. Exploring the regulatory networks controlled by miRNAs provides valuable information on new targets for therapy and predictive markers, demonstrating the potential for using miRNA-based interventions to treat BC in obese and elderly individuals. This review emphasizes the importance of integrated research strategies to understand the complex connections between obesity, aging, and miRNA regulation in BC.

Metformin acts on miR-181a-5p/PAI-1 axis in stem cells providing new strategies for improving age-related osteogenic differentiation decline

A general decline in the osteogenic differentiation capacity of human bone marrow mesenchymal stem cells (hBMSCs) in the elderly is a clinical consensus, with diverse opinions on the mechanisms. Many studies have demonstrated that metformin (MF) significantly protects against osteoporosis and reduces fracture risk. However, the exact mechanism of this effect remains unclear. In this study, we found that the decreased miR-181a-5p expression triggered by MF treatment plays a critical role in recovering the osteogenic ability of aging hBMSCs (derived from elderly individuals). Notably, the miR-181a-5p expression in hBMSCs was significantly decreased with prolonged MF (1000 μM) treatment. Further investigation revealed that miR-181a-5p overexpression markedly impairs the osteogenic ability of hBMSCs, while miR-181a-5p inhibition reveals the opposite result. We also found that miR-181a-5p could suppress the protein translation process of plasminogen activator inhibitor-1 (PAI-1), as evidenced by luciferase assays and Western blots. Additionally, low PAI-1 levels were associated with diminished osteogenic ability, whereas high levels promoted it. These findings were further validated in human umbilical cord mesenchymal stem cells (hUCMSCs). Finally, our in vivo experiment with a bone defects rat model confirmed that the agomiR-181a-5p (long-lasting miR-181a-5p mimic) undermined bone defects recovery, while the antagomiR-181a-5p (long-lasting miR-181a-5p inhibitor) significantly promoted the bone defects recovery. In conclusion, we found that MF promotes bone tissue regeneration through the miR-181a-5p/PAI-1 axis by affecting MSC osteogenic ability, providing new strategies for the treatment of age-related bone regeneration disorders.

A New Perspective on Pig Genetics and Breeding: microRNA

microRNA (miRNA) is a class of small non-coding RNA molecules that are widely expressed in organisms and play an important role in the regulation of gene expression at the post-transcriptional level. In recent years, researchers have begun to explore its effects on the development of domestic animals and have begun to think about its potential role in modern molecular breeding. Increasing evidence shows that miRNA play a central role in the regulation of pig fertility, pork product quality and disease resistance. Understanding the physiological mechanism of miRNA will be able to better guide future breeding work. In this paper, we will review the research progress of the function and mechanism of miRNA in combination with the above economic characteristics of pigs. The reported miRNA and their target genes were sorted out to evaluate their potential role in improving economic traits such as pig fertility, meat quality and disease resistance, to provide a reference for modern pig molecular breeding.

Deciphering adipose development: Function, differentiation and regulation

The overdevelopment of adipose tissues, accompanied by excess lipid accumulation and energy storage, leads to adipose deposition and obesity. With the increasing incidence of obesity in recent years, obesity is becoming a major risk factor for human health, causing various relevant diseases (including hypertension, diabetes, osteoarthritis and cancers). Therefore, it is of significance to antagonize obesity to reduce the risk of obesity-related diseases. Excess lipid accumulation in adipose tissues is mediated by adipocyte hypertrophy (expansion of pre-existing adipocytes) or hyperplasia (increase of newly-formed adipocytes). It is necessary to prevent excessive accumulation of adipose tissues by controlling adipose development. Adipogenesis is exquisitely regulated by many factors in vivo and in vitro, including hormones, cytokines, gender and dietary components. The present review has concluded a comprehensive understanding of adipose development including its origin, classification, distribution, function, differentiation and molecular mechanisms underlying adipogenesis, which may provide potential therapeutic strategies for harnessing obesity without impairing adipose tissue function.

Bioinformatics Analysis of miR-181a and Its Role in Adipogenesis, Obesity, and Lipid Metabolism Through Review of Literature

The miRNAs regulate various biological processes in the mammalian body system. The role of miR-181a in the development, progression, and expansion of cancers is well-documented. However, the role of miR-181a in adipogenesis; lipid metabolism; obesity; and obesity-related issues such as diabetes mellitus needs to be explored. Therefore, in the present study, the literature was searched and bioinformatics tools were applied to explore the role of miR-181a in adipogenesis. The list of adipogenic and lipogenic target genes validated through different publications were extracted and compiled. The network and functional analysis of these target genes was performed through in-silico analysis. The mature sequence of miR-181a of different species were extracted from and were found highly conserved among the curated species. Additionally, we also used various bioinformatics tools such as target gene extraction from Targetscan, miRWalk, and miRDB, and the list of the target genes from these different databases was compared, and common target genes were predicted. These common target genes were further subjected to the enrichment score and KEGG pathways analysis. The enrichment score of the vital KEGG pathways of the target genes is the key regulator of adipogenesis, lipogenesis, obesity, and obesity-related syndromes in adipose tissues. Therefore, the information presented in the current review will explore the regulatory roles of miR-181a in fat tissues and its associated functions and manifestations.

Early Life Programming of Adipose Tissue Remodeling and Browning Capacity by Micronutrients and Bioactive Compounds as a Potential Anti-Obesity Strategy

The early stages of life, especially the period from conception to two years, are crucial for shaping metabolic health and the risk of obesity in adulthood. Adipose tissue (AT) plays a crucial role in regulating energy homeostasis and metabolism, and brown AT (BAT) and the browning of white AT (WAT) are promising targets for combating weight gain. Nutritional factors during prenatal and early postnatal stages can influence the development of AT, affecting the likelihood of obesity later on. This narrative review focuses on the nutritional programming of AT features. Research conducted across various animal models with diverse interventions has provided insights into the effects of specific compounds on AT development and function, influencing the development of crucial structures and neuroendocrine circuits responsible for energy balance. The hormone leptin has been identified as an essential nutrient during lactation for healthy metabolic programming against obesity development in adults. Studies have also highlighted that maternal supplementation with polyunsaturated fatty acids (PUFAs), vitamin A, nicotinamide riboside, and polyphenols during pregnancy and lactation, as well as offspring supplementation with myo-inositol, vitamin A, nicotinamide riboside, and resveratrol during the suckling period, can impact AT features and long-term health outcomes and help understand predisposition to obesity later in life.

Association of lncRNA MEG3 rs941576 polymorphism, expression profile, and its related targets with the risk of obesity-related colorectal cancer: potential clinical insights

The identification of novel screening tools is imperative to empower the early detection of colorectal cancer (CRC). The influence of the long non-coding RNA maternally expressed gene 3 (MEG3) rs941576 single nucleotide polymorphism on CRC susceptibility remains uninvestigated. This research appraised MEG3 rs941576 association with the risk and clinical features of CRC and obesity-related CRC and its impact on serum MEG3 expression and its targets miR-27a/insulin-like growth factor 1 (IGF1)/IGF binding protein 3 (IGFBP3) and miR-181a/sirtuin 1 (SIRT1), along with the potential of these markers in obesity-related CRC diagnosis. 130 CRC patients (60 non-obese and 70 obese) and 120 cancer-free controls (64 non-obese and 56 obese) were enrolled. MEG3 targets were selected using bioinformatics analysis. MEG3 rs941576 was associated with magnified CRC risk in overall (OR (95% CI) 4.69(1.51-14.57), P = 0.0018) and stratified age and gender groups, but not with obesity-related CRC risk or MEG3/downstream targets' expression. Escalated miR-27a and IGFBP3 and reduced IGF1 serum levels were concomitant with MEG3 downregulation in overall CRC patients versus controls and obese versus non-obese CRC patients. Serum miR-181a and SIRT1 were upregulated in CRC patients versus controls but weren't altered in the obese versus non-obese comparison. Serum miR-181a and miR-27a were superior in overall and obesity-related CRC diagnosis, respectively; meanwhile, IGF1 was superior in distinguishing obese from non-obese CRC patients. Only serum miR-27a was associated with obesity-related CRC risk in multivariate logistic analysis. Among overall CRC patients, MEG3 rs941576 was associated with lymph node (LN) metastasis and tumor stage, serum MEG3 was negatively correlated with tumor stage, while SIRT1 was correlated with the anatomical site. Significant correlations were recorded between MEG3 and anatomical site, SIRT1 and tumor stage, and miR-27a/IGFBP3 and LN metastasis among obese CRC patients, while IGF1 was correlated with tumor stage and LN metastasis among non-obese CRC patients. Conclusively, this study advocates MEG3 rs941576 as a novel genetic marker of CRC susceptibility and prognosis. Our findings accentuate circulating MEG3/miR-27a/IGF1/IGFBP3, especially miR-27a as valuable markers for the early detection of obesity-related CRC. This axis along with SIRT1 could benefit obesity-related CRC prognosis.

Elucidating the Role of circTIAM1 in Guangling Large-Tailed Sheep Adipocyte Proliferation and Differentiation via the miR-485-3p/PLCB1 Pathway

Fat tissue-a vital energy storage organ-is intricately regulated by various factors, including circular RNA, which plays a significant role in modulating fat development and lipid metabolism. Therefore, this study aims to clarify the regulatory mechanism of sheep adipocyte proliferation and differentiation by investigating the involvement of circTIAM1, miR-485-3p, and its target gene PLCB1. Through previous sequencing data, circTIAM1 was identified in sheep adipocytes, with its circularization mechanism elucidated, confirming its cytoplasmic localization. Experimental evidence from RNase R treatment and transcription inhibitors highlighted that circTIAM1 is more stable than linear RNA. Additionally, circTIAM1 promoted sheep adipocyte proliferation and differentiation. Furthermore, bioinformatic analysis demonstrated a robust interaction between miR-485-3p and circTIAM1. Further experiments revealed that miR-485-3p inhibits fat cell proliferation and differentiation by inhibiting PLCB1, with circTIAM1 alleviating the inhibitory effect via competitive binding. In summary, our findings elucidate the mechanism through which circTIAM1 regulates Guangling Large-Tailed sheep adipocyte proliferation and differentiation via the miR-485-3p-PLCB1 pathway, offering a novel perspective for further exploring fat metabolism regulation.

An update on the secretory functions of brown, white, and beige adipose tissue: Towards therapeutic applications

Adipose tissue, including white adipose tissue (WAT), brown adipose tissue (BAT), and beige adipose tissue, is vital in modulating whole-body energy metabolism. While WAT primarily stores energy, BAT dissipates energy as heat for thermoregulation. Beige adipose tissue is a hybrid form of adipose tissue that shares characteristics with WAT and BAT. Dysregulation of adipose tissue metabolism is linked to various disorders, including obesity, type 2 diabetes, cardiovascular diseases, cancer, and infertility. Both brown and beige adipocytes secrete multiple molecules, such as batokines, packaged in extracellular vesicles or as soluble signaling molecules that play autocrine, paracrine, and endocrine roles. A greater understanding of the adipocyte secretome is essential for identifying novel molecular targets in treating metabolic disorders. Additionally, microRNAs show crucial roles in regulating adipose tissue differentiation and function, highlighting their potential as biomarkers for metabolic disorders. The browning of WAT has emerged as a promising therapeutic approach in treating obesity and associated metabolic disorders. Many browning agents have been identified, and nanotechnology-based drug delivery systems have been developed to enhance their efficacy. This review scrutinizes the characteristics of and differences between white, brown, and beige adipose tissues, the molecular mechanisms involved in the development of the adipocytes, the significant roles of batokines, and regulatory microRNAs active in different adipose tissues. Finally, the potential of WAT browning in treating obesity and atherosclerosis, the relationship of BAT with cancer and fertility disorders, and the crosstalk between adipose tissue with circadian system and circadian disorders are also investigated.

Multiple novel functions of circular RNAs in diabetes mellitus

Circular RNAs (circRNAs), as an emerging group of non-coding RNAs (ncRNAs), have received the attention given evidence indicating that these novel ncRNAs are implicated in various biological processes. Due to the absence of 5' and 3' ends in circ-RNAs, their two ends are covalently bonded together, and they are synthesised from pre-mRNAs in a process called back-splicing, which makes them more stable than linear RNAs. There is accumulating evidence showing that circRNAs play a critical role in the pathogenesis of diabetes mellitus (DM). Moreover, it has been indicated that dysregulation of circRNAs has made them promising diagnostic biomarkers for the detection of DM. Recently, increasing attention has been paid to investigate the mechanisms underlying the DM process. It has been demonstrated that there is a strong correlation between the expression of circRNAs and DM. Hence, our aim is to discuss the crosstalk between circRNAs and DM and its complications.

The miR-181 family: Wide-ranging pathophysiological effects on cell fate and function

MicroRNAs (miRNAs) are epigenetic regulators that can target and inhibit translation of multiple mRNAs within a given cell type. As such, a number of different pathways and networks may be modulated as a result. In fact, miRNAs are known to regulate many cellular processes including differentiation, proliferation, inflammation, and metabolism. This review focuses on the miR-181 family and provides information from the published literature on the role of miR-181 homologs in regulating a range of activities in different cell types and tissues. Of note, we have not included details on miR-181 expression and function in the context of cancer since this is a broad topic area requiring independent review. Instead, we have focused on describing the function and mechanism of miR-181 family members on differentiation toward a number of cell lineages in various non-neoplastic conditions (e.g., immune/hematopoietic cells, osteoblasts, osteoclasts, chondrocytes, adipocytes). We have also provided information on how modulation of miR-181 homologs can have positive effects on disease states such as cardiac abnormalities, pulmonary arterial hypertension, thrombosis, osteoarthritis, and vascular inflammation. In this context, we have used some examples of FDA-approved drugs that modulate miR-181 expression. We conclude by discussing some common mechanisms by which miR-181 homologs appear to regulate a number of different cellular processes and how targeting specific miR-181 family members may lead to attractive therapeutic approaches to treat a number of human disease or repair conditions, including those associated with the aging process.

The Role of Epicardial Adipose Tissue-Derived MicroRNAs in the Regulation of Cardiovascular Disease: A Narrative Review

Cardiovascular diseases have been leading cause of death worldwide for many decades, and obesity has been acknowledged as a risk factor for cardiovascular diseases. In the present review, human epicardial adipose tissue-derived miRNAs reported to be differentially expressed under pathologic conditions are discussed and summarized. The results of the literature review indicate that some of the epicardial adipose tissue-derived miRNAs are believed to be cardioprotective, while some others show quite the opposite effects depending on the underlying pathologic conditions. Furthermore, they suggest that that the epicardial adipose tissue-derived miRNAs have great potential as both a diagnostic and therapeutic modality. Nevertheless, mainly due to highly limited availability of human samples, it is very difficult to make any generalized claims on a given miRNA in terms of its overall impact on the cardiovascular system. Therefore, further functional investigation of a given miRNA including, but not limited to, the study of its dose effect, off-target effects, and potential toxicity is required. We hope that this review can provide novel insights to transform our current knowledge on epicardial adipose tissue-derived miRNAs into clinically viable therapeutic strategies for preventing and treating cardiovascular diseases.

Cherry juice alleviates high-fat diet-induced obesity in C57BL/6J mice by resolving gut microbiota dysbiosis and regulating microRNA

Cherry is a nutrient-rich food that is good for health. This study demonstrated the inhibitory action of dietary cherry juice on high-fat diet (HFD)-induced obesity in mice. Cherry juice intervention significantly decreased body weight, fat contents, and blood lipid levels in obese mice. The overproduction of proinflammatory cytokines was suppressed by dietary cherry juice, which was accompanied by the elevation of tight junction proteins to maintain intestinal barrier. Moreover, dietary cherry juice restored the decreased production of short-chain fatty acids (SCFAs) by regulating the composition and abundance of gut microbiota. In addition, dietary cherry juice also suppressed the expression of some microRNAs associated with obesity such as miR-200c-3p, miR-125a-5p, miR-132-3p, and miR-223-3p and target proteins related with microRNAs in the inguinal or epididymal white tissue in the obese mice. These results offer a fresh perspective on cherry juice's role in the prevention of obesity caused by the HFD.

Integrative Analysis of miRNAs Involved in Fat Deposition in Different Pig Breeds

BACKGROUND

miRNAs are a set of small, noncoding RNAs that bind to partially complementary sequences on target mRNAs. This leads to the post-transcriptional regulation of gene expression. Many studies have shown that microRNAs play critical roles in adipose cell differentiation and fat metabolism. The aim of this study was to explore the regulatory functions of miRNAs in fat deposition for the prevention and therapy of lipid metabolism-related diseases.

METHODS

The significant differences in the fat deposition of Laiwu (LW) pigs and Large White (LY) pigs were studied. To investigate the genetic relationships of miRNAs that regulate fat deposition, we performed a genome-wide analysis of miRNAs derived from subcutaneous adipose tissue of LW and LY pigs using RNA-seq.

RESULTS

There were 39 known miRNAs and 56 novel miRNAs significantly differential expressed between the two breeds of pigs. In the analysis of the Gene Ontology and KEGG pathways, predicted targets of these differentially expressed miRNAs were involved in several fat-associated pathways, such as the peroxisome proliferator-activated receptor (PPAR), mitogen-activated protein kinases (MAPK) and Wnt signaling pathways. In addition, ssc-miR-133a-3p, ssc-miR-486 and ssc-miR-1 each had a great impact on the development of porcine subcutaneous fat through the PPAR signaling pathway.

CONCLUSIONS

We explored the role of differentially expressed miRNAs and studied the mechanisms of adipogenesis and fat deposition between two different pig breeds. In addition, these results also contribute to research relevant to human obesity.

Circular RNA Profiling Identifies Novel circPPARA that Promotes Intramuscular Fat Deposition in Pigs

Intramuscular fat (IMF) content plays an important role in pork quality. Circular RNAs (circRNAs) implicate various biological processes; however, the regulatory mechanisms and functions of circRNAs in porcine IMF remains elusive. Hence, the study assessed the circRNA expression profiling in the longissimus dorsi muscle of pigs with high (H) and low (L) IMF content to unravel their regulatory functions in improving meat quality. The RNA sequencing analysis identified 29,732 circRNAs from six sampled pigs, most of which were exon-derived. In the muscle, 336 were differentially expressed (DE) between the H and L IMF groups; 196 circRNAs were upregulated, and 140 were downregulated. Subsequent qRT-PCR validation of 10 DE circRNAs revealed expression patterns consistent with the RNA-seq data. Gene ontology and KEGG enrichment analysis revealed that most significantly enriched DE circRNAs' host genes were linked to lipid metabolism and adipogenesis processes. The circRNA-miRNA regulatory network analysis found several circRNAs targeting miRNAs associated with adipogenesis. Finally, a novel circRNA, circPPARA, was identified with the expression positively correlated with the IMF content. Detailed analysis revealed that circPPARA was formed via head-to-tail splicing and was more stable than the linear PPARA, predominantly located in the cytoplasm. Functional studies using overexpression and siRNA constructs demonstrated that circPPARA promotes differentiation and hinders the proliferation of porcine intramuscular preadipocytes. Moreover, the dual-luciferase assay revealed that circPPARA adsorbed miR-429 and miR-200b, thereby promoting intramuscular adipogenesis in pigs. Our results identified a candidate circRNA, circPPARA, that affects porcine IMF content. The study provides knowledge of the regulatory functions of circRNAs in intramuscular adipogenesis and abundant resource for future research on circRNAs in pigs.

Genomic loci mispositioning in Tmem120a knockout mice yields latent lipodystrophy

Little is known about how the observed fat-specific pattern of 3D-spatial genome organisation is established. Here we report that adipocyte-specific knockout of the gene encoding nuclear envelope transmembrane protein Tmem120a disrupts fat genome organisation, thus causing a lipodystrophy syndrome. Tmem120a deficiency broadly suppresses lipid metabolism pathway gene expression and induces myogenic gene expression by repositioning genes, enhancers and miRNA-encoding loci between the nuclear periphery and interior. Tmem120a-/- mice, particularly females, exhibit a lipodystrophy syndrome similar to human familial partial lipodystrophy FPLD2, with profound insulin resistance and metabolic defects that manifest upon exposure to an obesogenic diet. Interestingly, similar genome organisation defects occurred in cells from FPLD2 patients that harbour nuclear envelope protein encoding LMNA mutations. Our data indicate TMEM120A genome organisation functions affect many adipose functions and its loss may yield adiposity spectrum disorders, including a miRNA-based mechanism that could explain muscle hypertrophy in human lipodystrophy.

MicroRNA Expression Influences Methylmercury-Induced Lipid Accumulation and Mitochondrial Toxicity in Caenorhabditis elegans

Metabolic effects of methylmercury (MeHg) are gaining wider attention. We have previously shown that MeHg causes lipid dysregulation in Caenorhabditis elegans (C. elegans), leading to altered gene expression, increased triglyceride levels and lipid storage, and altered feeding behaviors. Transcriptional regulators, such as transcription factors and microRNAs (miRNAs), have been shown to regulate lipid storage, serum triglycerides, and adipogenic gene expression in human and rodent models of metabolic diseases. As we recently investigated adipogenic transcription factors induced by MeHg, we were, therefore, interested in whether MeHg may also regulate miRNA sequences to cause metabolic dysfunction. Lipid dysregulation, as measured by triglyceride levels, lipid storage sites, and feeding behaviors, was assessed in wild-type (N2) worms and in transgenic worms that either were sensitive to miRNA expression or were unable to process miRNAs. Worms that were sensitive to the miRNA expression were protected from MeHg-induced lipid dysregulation. In contrast, the mutant worms that were unable to process miRNAs had exacerbated MeHg-induced lipid dysregulation. Concurrent with differential lipid homeostasis, miRNA-expression mutants had altered MeHg-induced mitochondrial toxicity as compared to N2, with the miRNA-sensitive mutants showing mitochondrial protection and the miRNA-processing mutants showing increased mitotoxicity. Taken together, our data demonstrate that the expression of miRNAs is an important determinant in MeHg toxicity and MeHg-induced metabolic dysfunction in C. elegans.

microRNAs in Human Adipose Tissue Physiology and Dysfunction

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

Exosomal MicroRNA-181a Derived From Mesenchymal Stem Cells Improves Gut Microbiota Composition, Barrier Function, and Inflammatory Status in an Experimental Colitis Model

Background: Mesenchymal stem cell (MSC)-derived exosomes (Exos) are recently proved to be a promising candidate for ulcerative colitis (UC), but the mechanism remains unclear. We investigated the effects of MSC-derived exosomal microRNA-181a (miR-181a) on gut microbiota, immune responses, and intestinal barrier function in UC.

Methods: Human bone marrow MSC-derived Exos were extracted and identified via transmission electron microscopy (TEM), Nanoparticle Tracking Analysis (NTA), and Western blotting. Dextran sodium sulfate (DSS)-induced colitis model and lipopolysaccharide (LPS)-induced human colonic epithelial cell (HCOEPIC) model were established to determine the effect of MSC-Exos on gut microbiota, immune responses, and intestinal barrier function in vivo and in vitro. The relationship between miR-181a and UC was analyzed using the Gene Expression Omnibus (GEO) database. MSC-miR-181-inhibitor was used to reveal the role of exosomal miR-181a in DSS-induced colitis.

Results: TEM and NTA results showed that Exos of a diameter of about 100 nm with the round and oval vesicle-like structure were successfully extracted. The expressions of the CD63, CD81, and TSG101 proteins were positive in these Exos. After MSC-Exo treatment, the colon length in colitis mice increased; colon inflammatory injury decreased; TNF-α, IL-6, IL-1β, IL-17, and IL-18 levels decreased; and Claudin-1, ZO-1, and IκB levels increased. In addition, the structure of the gut microbiota in DSS-induced colitis mice was changed by MSC-Exos. MSC-Exos showed antiapoptotic effects on LPS-induced HCOEPIC. The protective effects decreased significantly by treatment with MSC-Exos interfered with miR-181a inhibitor in vivo and in vitro.

Conclusion: MSC-derived exosomal miR-181a could alleviate experimental colitis by promoting intestinal barrier function. It exerted anti-inflammatory function and affected the gut microbiota. This indicated that MSC exosomal miR-181a may exhibit potential as a disease-modifying drug for UC.

Dysmetabolic adipose tissue in obesity: morphological and functional characteristics of adipose stem cells and mature adipocytes in healthy and unhealthy obese subjects

The way by which subcutaneous adipose tissue (SAT) expands and undergoes remodeling by storing excess lipids through expansion of adipocytes (hypertrophy) or recruitment of new precursor cells (hyperplasia) impacts the risk of developing cardiometabolic and respiratory diseases. In unhealthy obese subjects, insulin resistance, type 2 diabetes, hypertension, and obstructive sleep apnoea are typically associated with pathologic SAT remodeling characterized by adipocyte hypertrophy, as well as chronic inflammation, hypoxia, increased visceral adipose tissue (VAT), and fatty liver. In contrast, metabolically healthy obese individuals are generally associated with SAT development characterized by the presence of smaller and numerous mature adipocytes, and a lower degree of VAT inflammation and ectopic fat accumulation. The remodeling of SAT and VAT is under genetic regulation and influenced by inherent depot-specific differences of adipose tissue-derived stem cells (ASCs). ASCs have multiple functions such as cell renewal, adipogenic capacity, and angiogenic properties, and secrete a variety of bioactive molecules involved in vascular and extracellular matrix remodeling. Understanding the mechanisms regulating the proliferative and adipogenic capacity of ASCs from SAT and VAT in response to excess calorie intake has become a focus of interest over recent decades. Here, we summarize current knowledge about the biological mechanisms able to foster or impair the recruitment and adipogenic differentiation of ASCs during SAT and VAT development, which regulate body fat distribution and favorable or unfavorable metabolic responses.

MiR-502 Suppresses TNF-α-Induced Nucleus Pulposus Cell Apoptosis by Targeting TARF2

Intervertebral disc degeneration (IVDD) is a common cause of low back pain. This study is aimed at investigating the role of microRNAs (miRNAs) in regulating human nucleus pulposus (NP) cell injury induced by tumor necrosis factor- (TNF-) α in IVDD. In this study, we induced NP cells with 20 ng/mL TNF-α in vitro, which promoted the obvious apoptosis of NP cells and the activation of nuclear transcription factor (NF)-κB. In contrast, using the specific NF-κB inhibitor BAY 11-7082 to treat cells greatly impaired the activation of NF-κB and increased the sensitivity of NP cells to TNF-α-induced apoptosis. Moreover, both TNF-α and BAY 11-7082 treatments were associated with marked miRNA dysregulation, with miR-502 being upregulated by TNF-α treatment and downregulated by BAY 11-7082 treatment, respectively. And the overexpression of miR-502 enhanced NF-κB activation and suppressed apoptosis of human NP cells induced by TNF-α, whereas the opposite was observed following miR-502 inhibition. Last, through bioinformatic analyses and luciferase reporter gene experiments, we identified TRAF2, an important activator of NF-κB, as a miR-502 target gene. Similarly, siRNA-mediated knockdown of the TRAF2 expression also suppressed TNF-α-induced apoptosis and enhanced NF-κB activation. Our findings provide evidence indicating that miR-502 is a key regulator of apoptosis of human NP cells induced by TNF-α by targeting TRAF2 and activating NF-κB.

Implications of microRNA 21 and its involvement in the treatment of different type of arthritis

Arthritis is a kind of autoimmune disease, which includes many circumstances that affect joints, the tissues surrounding the joints, and other connective tissues. Osteoarthritis (OA) and rheumatoid arthritis (RA) are the common arthritis seen in many populations. Researchers have made extensive studies on all types of arthritis, novel drugs are being developed by many laboratories, but yet no treatment option is available for these diseases and need new insight into the molecular pathways and pathophysiology of all types of arthritis. MicroRNAs (miRNAs), a class of non-coding RNAs, have shown to be played a plenty of roles in both a suppressive and a promoting role in disease pathogenesis and progression. Among the classes of microRNAs, miR-21 is a widespread miRNA commonly upregulated in many diseases and suggesting that it plays an important role in cell proliferation, apoptosis, and invasion. It is highly expressed in osteoclast precursors and the pro-osteoclastogenic nature of miR-21 makes it a promising candidate as a therapeutic target to treat bone-related disorders. Up to now, there are few papers that demonstrate the role of miR-21 in arthritis and related bone disorders and the number of studies related to different types of arthritis is sparse. Therefore, the main thrust of this paper is to provide an overview of the current clinical evidence and significance of miR-21 in arthritis and bone-related inflammation disorders. We summarize the important research findings surrounding the role of miR-21 and its involvement in the treatment of different types of arthritis.

MiR-26b-5p regulates the preadipocyte differentiation by targeting FGF21 in goats

MicroRNAs are a class of highly conserved and widely distributed non-coding RNAs. It is known that miR-26b has a high abundance in adipose tissue and is considered to be an effective regulator of adipogenesis. However, it is unclear whether miR-26b-5p, the product of miR-26b precursor, has the same effect as miR-26b. In the present study, we explored the potential role of miR-26b-5p in preadipocyte differentiation of goats. We found that the expression of miR-26b-5p had dramatic change during goat intramuscular preadipocyte differentiation. Transfection and RT-qPCR revealed that overexpression of miR-26b-5p increased the level of adipogenic marker genes and lipid accumulation in goat preadipocyte, suggesting that miR-26b-5p positively regulates goat preadipocyte differentiation. Furthermore, bioinformatics analysis and dual fluorescein reporter assays were performed to predict and validate the targets of miR-26b-5p. The results showed that miR-26b-5p has a binding site in the 3'UTR of FGF21 and overexpression of miR-26b-5p significantly down-regulated the expression of FGF21 mRNA. Luciferase activity assays confirmed that miR-26b-5p is a positive regulator of goat intramuscular preadipocyte via targeting FGF21. These findings provide reference for further revealing of the regulatory networks of goat fat metabolism and contribute to a better understanding of intramuscular fat deposition in goats.

Role of microRNAs in myogenesis and their effects on meat quality in pig - A review

The demand for food is increasing day by day because of the increasing global population. Therefore, meat, the easiest and largely available source of protein, needs to be produced in large amounts with good quality. The pork industry is a significant shareholder in fulfilling the global meat demands. Notably, myogenesis- development of muscles during embryogenesis- is a complex mechanism which culminates in meat production. But the molecular mechanisms which govern the myogenesis are less known. The involvement of miRNAs in myogenesis and meat quality, which depends on factors such as myofiber composition and intramuscular fat contents which determine the meat color, flavor, juiciness, and water holding capacity, are being extrapolated to increase both the quantity and quality of pork. Various kinds of microRNAs (miRNAs), miR-1, miR-21, miR22, miR-27, miR-34, miR-127, miR-133, miR-143, miR-155, miR-199, miR-206, miR-208, miR-378, and miR-432 play important roles in pig skeletal muscle development. Further, the quality of meat also depends upon myofiber which is developed through the expression of different kinds of miRNAs at different stages. This review will focus on the mechanism of myogenesis, the role of miRNAs in myogenesis, and meat quality with a focus on the pig.

miR-340-5p inhibits sheep adipocyte differentiation by targeting ATF7

Several microRNAs (miRNAs) have been identified to play roles in adipocyte differentiation. However, little is known about their involvement in the differentiation of ovine intramuscular adipocytes. Here, the role of one such miRNA, miR-340-5p, in ovine adipocyte differentiation was investigated. Stromal vascular (SV) cells were isolated from skeletal muscle tissues of 1-month-old lambs and induced to differentiate into mature adipocytes. miRNA mimics and inhibitors were used for miR-340-5p overexpression and knockdown assays. For overexpression and knockdown of activating transcription factor 7 (ATF7), lentivirus infection was performed. Luciferase reporter assay was performed to determine the relationship between miR-340-5p and ATF7. The expression of adipogenesis marker genes, PPARγ, C/EBPα, FABP4, ADIPOQ, and ACC, and formation of lipid droplets were detected after the overexpression and inhibition of miR-340-5p, or upon overexpression or knockdown of ATF7. miR-340-5p inhibited the expression of the marker genes and the formation of lipid droplets. ATF7 positively regulated the expression of the marker genes and the formation of lipids. Thus, ATF7 is the target of miR-340-5p in sheep. Overall, these findings indicate that miR-340-5p acts as an inhibitor of the differentiation of intramuscular adipocytes by targeting ATF7. Our study provides a new theoretical basis for improving sheep meat quality.

miR-100-3p inhibits the adipogenic differentiation of hMSCs by targeting PIK3R1 via the PI3K/AKT signaling pathway

MicroRNAs play an important role in the adipogenic differentiation of human bone marrow mesenchymal stem cells (hMSCs). How miR-100-3p influences such adipogenesis, however, remains uncertain. In this study, hMSC adipogenic differentiation was associated with miR-100-3p downregulation, and overexpressing this miRNA inhibited adipogenesis and the expression of adipogenic marker genes. Through bioinformatics approaches, miR-100-3p can bind the 3'-untranslated region (3'-UTR) of the mRNA encoding phosphoinositide 3-kinase regulatory subunit 1 (PIK3R1) such that miR-100-3p overexpression resulted in significant reductions in PIK3R1 expression. Importantly, overexpressing PIK3R1 was sufficient to reverse the anti-adipogenic effects of miR-100-3p overexpression. PIK3R1 is a critical component of the PI3K/AKT signaling pathway, and miR-100-3p overexpression resulted in reduced AKT phosphorylation in the context of adipogenesis. In addition, the adipogenic differentiation of hMSCs in which miR-100-3p was overexpressed was further enhanced upon treatment with the PI3K/AKT agonist 740Y-P relative to miR-100-3p overexpression alone. Taken together, these findings provide evidence that miR-100-3p inhibits the adipogenic differentiation of hMSCs by targeting PIK3R1 via the PI3K/AKT signaling pathway.

Regulatory microRNAs in Brown, Brite and White Adipose Tissue

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

Small RNA sequencing reveals a novel tsRNA-06018 playing an important role during adipogenic differentiation of hMSCs

Transfer RNA-derived small RNAs (tsRNAs), a novel type of non-coding RNA derivative, are able to regulate a wide range of biological processes. What role these tsRNAs play in the regulation of human bone marrow mesenchymal stem cell (hMSCs) adipogenic differentiation remains uncertain. We induced the adipogenic differentiation of human bone marrow mesenchymal cells (hMSCs) and then performed small RNA transcriptomic sequencing, leading us to identify tsRNA-06018 as a target of interest based upon resultant the tsRNA expression profiles. When tsRNA-06018 was knocked down, this led to the inhibition of adipogenesis and a decrease in adipogenic marker expression. When STC2 was overexpressed, this impaired the adipogenic differentiation of these cells. We further used luciferase reporter assays to confirm that tsRNA-06018 directly binds the 3'-untranslated region (3'-UTR) of STC2. In addition, we determined that both knocking down tsRNA-06018 and overexpressing STC2 increased extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation within cells. We also assessed that the adipogenic differentiation of hMSCs in which tsRNA-06018 was knocked down was further enhanced upon the addition of the ERK1/2 inhibitor U0126 as compared tsRNA-06018 knockdown alone. Taken together, using small RNA sequencing we profiled tsRNAs in hMSCs during the process of adipogenesis, leading us to identify tsRNA-06018 as a novel regulator of this differentiation process. This tsRNA was able to regulate adipogenic differentiation by targeting STC2 via the ERK1/2 signalling pathway.

Effect of Progressive Resistance Training on Circulating Adipogenesis-, Myogenesis-, and Inflammation-Related microRNAs in Healthy Older Adults: An Exploratory Study

BACKGROUND

Functional and physiological adaptations induced by resistance training have been extensively studied in older adults. However, microRNA (miRNA) as the novel regulator in protective effects remains poorly understood.

OBJECTIVE

The purpose of an exploratory study was to analyze the response of a panel of circulating miRNAs to adaptations mediated by resistance training.

METHODS

Ten healthy older adults (age: 67.6 ± 2.2 years, 7 women and 3 men) without previous experience in resistance training were recruited. Blood samples were collected at baseline and after a 12-week resistance training. Next-generation sequencing was used to determine circulating miRNA responses to chronic resistance training.

RESULTS

After the 12-week training, physical functions including grip strength, lower body strength and endurance, and walking capacity were improved in the older adults, while the serum levels of leptin (from 18.1 ± 20.0 to 14.9 ± 17.6 ng/mL, p = 0.029) and tumor necrosis factor alpha (TNFα; from 4.4 ± 0.6 to 4.0 ± 0.6 pg/mL, p < 0.001) were significantly decreased. In addition, adipogenesis-related miRNAs (miR-103a-3p, -103b, -143-5p, -146b-3p, -146b-5p, -17-5p, -181a-2-3p, -181b-5p, -199a-5p, -204-3p, and -378c), anti-adipogenesis-related miRNAs (miR-155-3p, -448, and -363-3p), myogenesis-related miRNAs (miR-125b-1-3p, -128-3p, -133a-3p, 155-3p, -181a-2-3p, -181b-5p, -199a-5p, -223-3p, and -499a-5p), and inflammation-related miRNAs (miR-146b-3p, -146b-5p, -155-3p, -181a-2-3p, and -181b-5p) were changed significantly in the older adults after training (fold change >2, p < 0.05). The log2 fold change of miRNA-125-1-3p was inversely correlated with delta walking time (R = -0.685, p = 0.029) and change in insulin-like growth factor 1 (R = -0.644, p = 0.044).

CONCLUSIONS

Our results can help explain the link between specific circulating miRNAs and beneficial effects of resistance training on functional and physiological adaptations in older adults.

MicroRNAs and obesity-induced endothelial dysfunction: key paradigms in molecular therapy

The endothelium plays a pivotal role in maintaining vascular health. Obesity is a global epidemic that has seen dramatic increases in both adult and pediatric populations. Obesity perturbs the integrity of normal endothelium, leading to endothelial dysfunction which predisposes the patient to cardiovascular diseases. MicroRNAs (miRNAs) are short, single-stranded, non-coding RNA molecules that play important roles in a variety of cellular processes such as differentiation, proliferation, apoptosis, and stress response; their alteration contributes to the development of many pathologies including obesity. Mediators of obesity-induced endothelial dysfunction include altered endothelial nitric oxide synthase (eNOS), Sirtuin 1 (SIRT1), oxidative stress, autophagy machinery and endoplasmic reticulum (ER) stress. All of these factors have been shown to be either directly or indirectly caused by gene regulatory mechanisms of miRNAs. In this review, we aim to provide a comprehensive description of the therapeutic potential of miRNAs to treat obesity-induced endothelial dysfunction. This may lead to the identification of new targets for interventions that may prevent or delay the development of obesity-related cardiovascular disease.

A novel tsRNA-16902 regulating the adipogenic differentiation of human bone marrow mesenchymal stem cells

BACKGROUND

Transfer RNA-derived small RNAs (tsRNAs) are a recently discovered form of non-coding RNA capable of regulating myriad physiological processes. The role of tsRNAs in hMSC adipogenic differentiation, however, remains incompletely understood. The purpose of this study was to identify the novel tsRNA-16902 as a regulator of hMSC adipogenic differentiation.

METHODS

In this study, we conducted transcriptomic sequencing of hMSCs after inducing their adipogenic differentiation, and we were thereby able to clarify the molecular mechanism underlying the role of tsRNA-16902 in this context via a series of molecular biology methods.

RESULTS

When we knocked down tsRNA-16902 expression, this impaired hMSC adipogenic differentiation and associated marker gene expression. Bioinformatics analyses further revealed tsRNA-16902 to target retinoic acid receptor γ (RARγ). Luciferase reporter assays also confirmed the ability of tsRNA-16902 to bind to the RARγ 3'-untranslated region. Consistent with this, RARγ overexpression led to impaired hMSC adipogenesis. Further analyses revealed that Smad2/3 phosphorylation was increased in cells that either overexpressed RARγ or in which tsRNA-16902 had been knocked down. We also assessed the adipogenic differentiation of hMSCs in which tsRNA-16902 was knocked down and at the same time a Smad2/3 inhibitor was added to disrupt Smad2/3 phosphorylation. The adipogenic differentiation of hMSCs in which tsRNA-16902 was knocked down was further enhanced upon the addition of a Smad2/3 signaling inhibitor relative to tsRNA-16902 knockdown alone.

CONCLUSIONS

Through a comprehensive profiling analysis of tsRNAs that were differentially expressed in the context of hMSC adipogenic differentiation, we were able to identify tsRNA-16902 as a previously uncharacterized regulator of adipogenesis. tsRNA-16902 is able to regulate hMSC adipogenic differentiation by targeting RARγ via the Smad2/3 signaling pathway. Together, our results may thus highlight novel strategies of value for treating obesity.

Functions of Circular RNAs in Regulating Adipogenesis of Mesenchymal Stem Cells

The mesenchymal stem cells (MSCs) are known as highly plastic stem cells and can differentiate into specialized tissues such as adipose tissue, osseous tissue, muscle tissue, and nervous tissue. The differentiation of mesenchymal stem cells is very important in regenerative medicine. Their differentiation process is regulated by signaling pathways of epigenetic, transcriptional, and posttranscriptional levels. Circular RNA (circRNA), a class of noncoding RNAs generated from protein-coding genes, plays a pivotal regulatory role in many biological processes. Accumulated studies have demonstrated that several circRNAs participate in the cell differentiation process of mesenchymal stem cells in vitro and in vivo. In the current review, characteristics and functions of circRNAs in stem cell differentiation will be discussed. The mechanism and key role of circRNAs in regulating mesenchymal stem cell differentiation, especially adipogenesis, will be reviewed and discussed. Understanding the roles of these circRNAs will present us with a more comprehensive signal path network of modulating stem cell differentiation and help us discover potential biomarkers and therapeutic targets in clinic.

miR-802 participates in the inflammatory process of inflammatory bowel disease by suppressing SOCS5

The present study aims to reveal the detailed molecular mechanism of microRNA (miR)-802 in the progression of inflammatory bowel disease (IBD). IBD tissues were obtained from IBD patients, followed by CD4+ cells isolation. Then, qRT-PCR and ELISA were used to detect the expression of miR-802, suppressor of cytokine signaling 5 (SOCS5), interleukin (IL)-17A and tumor necrosis factor (TNF)-α. Transfection of miR-802 mimics and miR-802 inhibitor in CD4+ cells was detected by Western blot. TargetScan and luciferase reporter assay were used to detect the relationship between SOCS5 and miR-802. Finally, colitis mice model was established to verify whether miR-802 inhibitor was involved in the protective effect of colonic mucosa. The miR-802 was highly expressed in inflamed mucosa and PBMC cells of IBD. The highest expression of miR-802 was observed in CD4+ T cells based on different immune cell subsets analysis. SOCS5 was the target gene of miR-802. The mice model experiments showed that blockade of miR-802 could alleviate mice colitis. Our study suggests that up-regulation of miR-802 plays an important role in inflammatory process of IBD via targeting SOCS5. Moreover, the differentiation of Th17 and secretion of TNF-α in IBD could be stimulated by miR-802.

Adipogenesis for soft tissue reconstruction

PURPOSE OF REVIEW

It has been increasingly common to use adipose tissue for regenerative and reconstructive purposes. Applications of autologous fat transfer and different stem cell therapies have significant limitations and adipose tissue engineering may have the potential to be an important strategy in the reconstruction of large tissue defects. A better understanding of adipogenesis will help to develop strategies to make adipose tissue more effective for repairing volumetric defects.

RECENT FINDINGS

We provide an overview of the current applications of adipose tissue transfer and cellular therapy methods for soft tissue reconstruction, cellular physiology, and factors influencing adipogenesis, and adipose tissue engineering. Furthermore, we discuss mechanical properties and vascularization strategies of engineered adipose tissue, and its potential applications in the clinical settings.

SUMMARY

Autologous fat tissue transfer is the standard of care technique for the majority of surgeons; however, high resorption rates, poor perfusion within a large volume fat graft and widely inconsistent graft survival are the main limitations. Adipose tissue engineering is a promising field to reach the first goal of producing adipose tissue which has more predictable survival and higher graft retention rates. Advancements of scaffold and vascularization strategies will contribute to metabolically and functionally more relevant adipose tissue engineering.

Regulation of chicken vanin1 gene expression by peroxisome proliferators activated receptor α and miRNA-181a-5p

Objective

Vanin1 (VNN1) is a pantetheinase that can catalyze the hydrolysis of pantetheine to produce pantothenic acid and cysteamine. Our previous studies showed that VNN1 is specifically expressed in chicken liver. In this study, we aimed to investigate the roles of peroxisome proliferators activated receptor α (PPARα) and miRNA-181a-5p in regulating VNN1 gene expression in chicken liver.

Methods

5′-RACE was performed to identify the transcription start site of chicken VNN1. JASPAR and TFSEARCH were used to analyze the potential transcription factor binding sites in the promoter region of chicken VNN1 and miRanda was used to search miRNA binding sites in 3′ untranslated region (3′UTR) of chicken VNN1. We used a knock-down strategy to manipulate PPARα (or miRNA-181a-5p) expression levels in vitro to further investigate its effect on VNN1 gene transcription. Luciferase reporter assays were used to explore the specific regions of VNN1 targeted by PPARα and miRNA-181a-5p.

Results

Sequence analysis of the VNN1 promoter region revealed several transcription factor-binding sites, including hepatocyte nuclear factor 1α (HNF1α), PPARα, and CCAAT/enhancer binding protein α. GW7647 (a specific agonist of PPARα) increased the expression level of VNN1 mRNA in chicken primary hepatocytes, whereas knockdown of PPARα with siRNA increased VNN1 mRNA expression. Moreover, the predicted PPARα-binding site was confirmed to be necessary for PPARα regulation of VNN1 gene expression. In addition, the VNN1 3′UTR contains a sequence that is completely complementary to nucleotides 1 to 7 of miRNA-181a-5p. Overexpression of miR-181a-5p significantly decreased the expression level of VNN1 mRNA.

Conclusion

This study demonstrates that PPARα is an important transcriptional activator of VNN1 gene expression and that miRNA-181a-5p acts as a negative regulator of VNN1 expression in chicken hepatocytes.

CircRNA Expression Profile during Yak Adipocyte Differentiation and Screen Potential circRNAs for Adipocyte Differentiation

The yak (Bos grunniens) is subjected to nutritional deficiency during the whole winter grazing season; deciphering the adipose metabolism and energy homeostasis under cold and nutrients stress conditions could be a novel way to understand the specific mechanism of energy metabolism. Circular RNAs (circRNAs) have elucidated that they play a key role in many biological events, but the regulatory function of adipose development remains mostly unknown. Therefore, the expression pattern of circRNAs were identified for the first time during yak adipocyte differentiation to gain insight into their potential functional involvement in bovine adipogenesis. We detected 7203 circRNA candidates, most of them contained at least two exons, and multiple circRNA isoforms could be generated from one parental gene. Analysis of differential expression circRNAs displayed that 136 circRNAs were differentially expressed at day 12 (Ad) after adipocyte differentiation, compared with the control at day 0 (Pread 0), while 7 circRNAs were detected on day 2. Sanger sequencing validated that six circRNAs had head-to-tail junction, and quantitative real-time PCR (qPCR) results revealed that the expression patterns of ten circRNAs were consistent with their expression levels from RNA-sequencing (RNA-seq) data. We further predicted the networks of circRNA-miRNA-gene based on miRNAs sponging by circRNAs, in which genes were participated in the adipocyte differentiation-related signaling pathways. After that, we constructed several adipocyte differentiation-related ceRNAs and revealed six circRNAs (novel_circ_0009127, novel_circ_0000628, novel_circ_0011513, novel_circ_0010775, novel_circ_0006981 and novel_circ_0001494) were related to adipogenesis. Furthermore, we analyzed the homology among yak, human and mouse circRNAs and found that 3536 yak circRNAs were homologous to human and mouse circRNAs. In conclusion, these findings provide a solid basis for the investigation of yak adipocyte differentiation-related circRNAs and serve as a great reference to study the energy metabolism of high-altitude animals.

MiR-130a-3p Inhibits PRL Expression and Is Associated With Heat Stress-Induced PRL Reduction

MicroRNAs (MiRNAs) play critical roles in the regulation of pituitary function. MiR-130a-3p has previously been found to be down-regulated in prolactinoma, but its roles in prolactin (PRL) regulation and the underlying mechanisms are still unclear. Heat stress has been shown to induce alteration of endocrine hormones and miRNAs expressions. However, there is limited information regarding the emerging roles of miRNAs in heat stress response. In this study, we transfected miR-130a-3p mimic into the pituitary adenoma cells (GH3 cells) to investigate the function of miR-130a-3p in regulating PRL. Our results showed that miR-130a-3p overexpression significantly decreased the PRL expression at both mRNA and protein levels. Subsequently, estrogen receptor α (ERα) was identified as a direct target of miR-130a-3p by bioinformatics prediction, luciferase reporter assay and western blotting assay. Furthermore, the inhibition of ERα caused by estrogen receptor antagonist significantly reduced the PRL expression. Overexpression of ERα rescued the suppressed expression of PRL caused by miR-130a-3p mimic. Besides, we also studied the effect of heat stress on PRL and miRNAs expressions. Interestingly, we found that heat stress reduced PRL and ERα expressions while it increased miR-130a-3p expression both in vitro and in vivo. Taken together, our results indicate that miR-130a-3p represses ERα by targeting its 3'UTR leading to a decrease in PRL expression, and miR-130a-3p is correlative with heat stress-induced PRL reduction, which provides a novel mechanism that miRNAs are involved in PRL regulation.

Transcriptome analysis of miRNA and mRNA in the livers of pigs with highly diverged backfat thickness

Fat deposition is very important in pig production, and its mechanism is not clearly understood. MicroRNAs (miRNAs) play critical roles in fat deposition and energy metabolism. In the current study, we investigated the mRNA and miRNA transcriptome in the livers of Landrace pigs with extreme backfat thickness to explore miRNA-mRNA regulatory networks related to lipid deposition and metabolism. A comparative analysis of liver mRNA and miRNA transcriptomes from pigs (four pigs per group) with extreme backfat thickness was performed. We identified differentially expressed genes from RNA-seq data using a Cufflinks pipeline. Seventy-one differentially expressed genes (DEGs), including twenty-eight well annotated on the porcine reference genome genes, were found. The upregulation genes in pigs with higher backfat thickness were mainly involved in fatty acid synthesis, and included fatty acid synthase (FASN), glucokinase (GCK), phosphoglycerate dehydrogenase (PHGDH), and apolipoprotein A4 (APOA4). Cytochrome P450, family 2, subfamily J, polypeptide 34 (CYP2J34) was lower expressed in pigs with high backfat thickness, and is involved in the oxidation of arachidonic acid. Moreover, 13 differentially expressed miRNAs were identified. Seven miRNAs were associated with fatty acid synthesis, lipid metabolism, and adipogenic differentiation. Based on comprehensive analysis of the transcriptome of both mRNAs and miRNAs, an important regulatory network, in which six DEGs could be regulated by differentially expressed miRNAs, was established for fat deposition. The negative correlate in the regulatory network including, miR-545-5p and GRAMD3, miR-338 and FASN, and miR-127, miR-146b, miR-34c, miR-144 and THBS1 indicate that direct suppressive regulation may be involved in lipid deposition and energy metabolism. Based on liver mRNA and miRNA transcriptomes from pigs with extreme backfat thickness, we identified 28 differentially expressed genes and 13 differentially expressed miRNAs, and established an important miRNA-mRNA regulatory network. This study provides new insights into the molecular mechanisms that determine fat deposition in pigs.

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.

Long-term dietary resveratrol supplementation decreased serum lipids levels, improved intramuscular fat content, and changed the expression of several lipid metabolism-related miRNAs and genes in growing-finishing pigs1

This study was conducted to evaluate the effects of dietary resveratrol supplementation on growth performance, meat quality, serum lipid profiles, intramuscular fat (IMF) deposition, and the expression levels of several lipid metabolism-related miRNAs and genes in growing-finishing pigs. A total of 36 healthy crossbred pigs (Duroc × Landrace × Yorkshire) with an average initial BW of 24.67 ± 3.49 kg were randomly divided into two groups and fed either with a basal diet (CON) or basal diet containing 600 mg/kg resveratrol (RES). The trial lasted for 119 d. Resveratrol had no significant effect on growth performance and carcass characteristics. However, the concentrations of serum triglyceride, total cholesterol, low-density lipoprotein cholesterol, and very low-density lipoprotein were lower in RES group than those of CON group (P < 0.05). Dietary resveratrol supplementation increased the IMF content in longissimus dorsi (P < 0.05), up-regulated mRNA abundances of peroxisome proliferator-activated receptor γ, fatty acid synthase, acetyl-CoA carboxylase, and lipoprotein lipase (P < 0.05), while downregulated mRNA abundances of carnitine palmitoyl transferase-1, sirtuin 1, and peroxisome proliferator-activated receptor α (P < 0.05) in LM. In addition, resveratrol enhanced (P < 0.05) the expression of ssc-miR-181a, ssc-miR-370, and ssc-miR-21 and reduced (P < 0.05) the expression of ssc-miR-27a in longissimus dorsi. These results indicated that dietary resveratrol supplementation significantly improved IMF content and decreased serum lipids levels, which might be related with the changes in ssc-miR-181a, ssc-miR-370, ssc-miR-21, ssc-miR-27a and their downstream genes expression.

miR-181a/b therapy in lung cancer: reality or myth?

Despite substantial progress in oncology, lung cancer remains the number one malignancy in terms of both incidence and mortality rates, and there thus remains an urgent need for new therapeutic alternatives. MicroRNA (miRNA) have an important role in cancer initiation and progression due to their capacity to interfere with transcriptional signaling and regulate key cellular processes. miR-181a and miR-181b (miR-181a/b), which are located on chromosomes 1 and 9, are pathologically expressed in the tumor tissue and plasma of patients diagnosed with lung cancer. The miR-181a/b regulatory mechanisms are sophisticated and are directly related to different target genes. In recent years, an ever-increasing number of studies have focused on the biological relevance of miR-181a/b in key cellular processes. In this paper, we aim to discuss the challenging experimental data related to miR-181a/b and their potential use for the development of new therapeutic approaches in lung cancer. We will further present the ongoing issues regarding the regulation of their multiple target genes, and their potential use as biomarkers and therapeutic targets in this deadly malignancy.

Protein expression profile and microRNA expression signature in estrogen receptor-positive and -negative breast cancers: report of two cases

Background

Identification of the proteins that are associated with estrogen receptor (ER) status is a first step in selecting drugs against hormone-dependent breast cancer. Recently, the proteins associated with ER status were reported using liquid chromatography and tandem mass spectrometry, and microRNA (miRNA) profiling of breast cancer subtype was demonstrated using real-time-PCR.

Methods

We present herein two cases with differential protein expression and miRNA profiling in ER-positive and -negative breast cancer.

Results

Proteins associated with fatty acid metabolism were uniquely detected in ER-positive breast cancer. The level of miR-181a expression in ER-positive cancer was higher than that in ER-negative cancer, while the expression of miR-27a, miR-107, and miR-195 was lower in ER-positive compared with ER-negative cancer.

Conclusion

These cases suggest that fatty acid synthase (FAS) and FAS-related miRNAs are important in ER-positive breast cancer.

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.

MiRNA-seq reveals that miR-124-3p inhibits adipogenic differentiation of the stromal vascular fraction in sheep via targeting C/EBPα

MicroRNAs (miRNAs) are small noncoding 20-25 nt RNA molecules that regulate gene expression by posttranscriptional repression of messenger RNA. There have been few investigations on the profiles and functions of miRNAs in ovine subcutaneous fat; their roles in the metabolism and deposition of subcutaneous fat also remain unclear. In this study, small RNA libraries were constructed for 2 important Chinese local sheep breeds, Small-tailed Han Sheep, and Shanxi Meat Sheep Dam Line, and used for high-throughput sequencing. Differentially expressed miRNAs were identified, revealing the effect of miR-124-3p on adipogenic differentiation by targeting C/EBPα. Our results provide both a comprehensive understanding of miRNA expression patterns in sheep subcutaneous fat and an insight into the specific roles of miRNAs in adipogenesis.

A cellular perspective of adipogenesis transcriptional regulation

Adipose cells store lipids in the cytoplasm and signal systemically through secretion of adipokines and other molecules that regulate body energy metabolism. Differentiation of fat cells and its regulation has been the focus of extensive research since the early 1970s. In this review, we had attempted to examine the research bearing on the control of adipose cell differentiation, some of it dating back to the early days when Howard Green and his group described the preadipocyte cell lines 3T3-L1 and 3T3-F442A during 1974-1975. We also concentrated our attention on research published during the last few years, emphasizing data described on transcription factors that regulate adipose differentiation, outside of those that were reported earlier as part of the canonical adipogenic transcriptional cascade, which has been the subject of ample reviews by several groups of researchers. We focused on the studies carried out with the two preadipocyte cell culture models, the 3T3-L1 and 3T3-F442A cells that have provided essential data on adipose biology.