miR-429 Inhibits Differentiation and Promotes Proliferation in Porcine Preadipocytes

DNI-MDCAP: improvement of causal MiRNA-disease association prediction based on deep network imputation

BACKGROUND

MiRNAs are involved in the occurrence and development of many diseases. Extensive literature studies have demonstrated that miRNA-disease associations are stratified and encompass ~ 20% causal associations. Computational models that predict causal miRNA-disease associations provide effective guidance in identifying novel interpretations of disease mechanisms and potential therapeutic targets. Although several predictive models for miRNA-disease associations exist, it is still challenging to discriminate causal miRNA-disease associations from non-causal ones. Hence, there is a pressing need to develop an efficient prediction model for causal miRNA-disease association prediction.

RESULTS

We developed DNI-MDCAP, an improved computational model that incorporated additional miRNA similarity metrics, deep graph embedding learning-based network imputation and semi-supervised learning framework. Through extensive predictive performance evaluation, including tenfold cross-validation and independent test, DNI-MDCAP showed excellent performance in identifying causal miRNA-disease associations, achieving an area under the receiver operating characteristic curve (AUROC) of 0.896 and 0.889, respectively. Regarding the challenge of discriminating causal miRNA-disease associations from non-causal ones, DNI-MDCAP exhibited superior predictive performance compared to existing models MDCAP and LE-MDCAP, reaching an AUROC of 0.870. Wilcoxon test also indicated significantly higher prediction scores for causal associations than for non-causal ones. Finally, the potential causal miRNA-disease associations predicted by DNI-MDCAP, exemplified by diabetic nephropathies and hsa-miR-193a, have been validated by recently published literature, further supporting the reliability of the prediction model.

CONCLUSIONS

DNI-MDCAP is a dedicated tool to specifically distinguish causal miRNA-disease associations with substantially improved accuracy. DNI-MDCAP is freely accessible at http://www.rnanut.net/DNIMDCAP/ .

Circular RNAs: Emerging Modulators in the Pathophysiology of Polycystic Ovary Syndrome and their Clinical Implications

Polycystic ovary syndrome (PCOS) is a prevalent endocrine/metabolic disorder in women of reproductive age. PCOS is characterized by hyperandrogenism, polycystic ovary morphology, and ovulatory dysfunction/anovulation. It involves multiple effects in patients, including granulosa/theca cell hyperplasia, menstrual disturbances, infertility, acne, obesity, insulin resistance, and cardiovascular disorders. Biochemical analyses and the results of RNA sequencing studies in recent years have shown a type of non-coding RNAs as a splicing product known as circular RNAs (circRNAs). Several biological functions have been identified in relation to circRNAs, including a role in miRNA sponge, protein sequestration, increased parental gene expression, and translation leading to polypeptides. These circular molecules are more plentiful and specialized than other types of RNAs. For this reason, they are referred to as potential biomarkers in different diseases. Evidence suggests that circRNAs may have regulatory potentials through different signaling pathways, such as the miRNA network. Probably most experts in the field of obstetricians are not aware of circRNAs as a useful biomarker. Therefore, this review focused on the researches that have been done on the involvement of circRNAs in PCOS and summarized recent supportive evidence, and evaluated the circRNA association and mechanisms involved in PCOS.

Goat miR-92a-3p Targets APOL6 Gene to Regulate the Differentiation of Intramuscular Precursor Adipocytes

The quality of lamb meat is positively correlated with intramuscular fat content. In recent years, a large number of studies have shown that miRNAs play an important role in the proliferation and differentiation of adipocytes. In this study, we aimed to explore the effect of miR-92a-3p on the differentiation of goat intramuscular preadipocytes. The results showed that the expression level of miR-92a-3p was low in the early stage of differentiation, reached the highest level on the third day of differentiation, and then decreased. And miR-92a-3p can inhibit the accumulation of lipid droplets and down-regulate the determinants of adipogenic differentiation. Mechanistically, by predicting target genes, we found that miR-92a-3p affects the differentiation of goat intramuscular preadipocytes and the accumulation of lipid droplets by regulating the expression of goat gene APOL6. This study provides important new information to better understand the relationship between miRNAs and the differentiation of goat intramuscular preadipocytes, thus providing a new reference for goat intramuscular adipogenesis.

Comprehensive Analysis of the lncRNA-miRNA-mRNA Regulatory Network for Intramuscular Fat in Pigs

Intramuscular fat (IMF) is an essential trait closely related to meat quality. The IMF trait is a complex quantitative trait that is regulated by multiple genes. In order to better understand the process of IMF and explore the key factors affecting IMF deposition, we identified differentially expressed mRNA, miRNA, and lncRNA in the longissimus dorsi muscle (LD) between Songliao Black (SL) pigs and Landrace pigs. We obtained 606 differentially expressed genes (DEGs), 55 differentially expressed miRNAs (DEMs), and 30 differentially expressed lncRNAs (DELs) between the SL pig and Landrace pig. Enrichment results from GO and KEGG indicate that DEGs are involved in fatty acid metabolism and some pathways related to glycogen synthesis. We constructed an lncRNA-miRNA-mRNA interaction network with 18 DELs, 11 DEMs, and 42 DEGs. Finally, the research suggests that ARID5B, CPT1B, ACSL1, LPIN1, HSP90AA1, IRS1, IRS2, PIK3CA, PIK3CB, and PLIN2 may be the key genes affecting IMF deposition. The LncRNAs MSTRG.19948.1, MSTRG.13120.1, MSTRG.20210.1, and MSTRG.10023.1, and the miRNAs ssc-miRNA-429 and ssc-miRNA-7-1, may play a regulatory role in IMF deposition through their respective target genes. Our research provides a reference for further understanding the regulatory mechanism of IMF.

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.

miR-381-3p Inhibits Intramuscular Fat Deposition through Targeting FABP3 by ceRNA Regulatory Network

Intramuscular fat (IMF) deposition is an important determinant of pork quality and a complex process facilitated by non-coding ceRNAs. In this study, 52 Berkshire × Anqing Sixwhite crossbred pigs were slaughtered to measure eight carcass and pork quality traits. Whole-transcriptome sequencing analysis was performed using longissimus dorsi samples of six low- and high-IMF samples; 34 ceRNA networks, based on 881, 394, 158 differentially expressed (DE) lncRNAs, miRNAs, and mRNAs, were constructed. Following weighted gene co-expression network analysis between the low and high IMF, only one ceRNA, lncRNA4789/miR-381-3p/FABP3, that showed similar DE trend in longissimus dorsi tissue was retained. Dual-luciferase reporter assays further indicated that FABP3 was a direct, functional target of miR-381-3p, where miR-381-3p overexpression inhibited the mRNA and protein expression of FABP3. In addition, overexpressed lncRNA4789 attenuated the effect of miR-381-3p on FABP3 by sponging miR-381-3p. Cell function verification experiment demonstrated that miR-381-3p suppressed IMF deposition by inhibiting preadipocyte cell differentiation and lipid droplet deposition via the suppression of FABP3 expression in the peroxisome proliferator-activated receptor signalling pathway, whereas lncRNA4789 rescued FABP3 expression by sponging miR-381-3p. Our study may aid in identifying novel molecular markers for its optimization in IMF which is of importance in breeding for improving pork quality.

Resveratrol Inhibits Proliferation and Differentiation of Porcine Preadipocytes by a Novel LincRNA-ROFM/miR-133b/AdipoQ Pathway

Resveratrol (RES) has a wide range of biological and pharmacological activities with various health benefits for humans as a food additive. In animal production, RES has been considered a potential functional feed additive for producing high-quality pork. Long noncoding RNAs (lncRNAs) have emerged as essential regulators of fat metabolism, and phytochemicals can regulate fat metabolism through lncRNA. However, it is unclear whether RES can improve back-fat thickness by regulating lncRNA. In this study, we identified a novel lncRNA, which was named a long intergenic non-protein coding RNA, a regulator of fat metabolism (LincRNA-ROFM), from our previous lncRNA sequencing data. LincRNA-ROFM can inhibit adipocyte proliferation and differentiation. In-depth analyses showed that LincRNA-ROFM acts as a molecular sponge for miR-133b, and adiponectin (AdipoQ) is a direct target of miR-133b in porcine preadipocytes. In addition, the expression of LincRNA-ROFM was positively correlated with AdipoQ. RES can promote the expression of LincRNA-ROFM by PPARα and C/EBPα. Altogether, our research showed that LincRNA-ROFM acts as a ceRNA to sequester miR-133b and is upregulated by RES, leading to heightened AdipoQ expression, and thus decreased adipocyte proliferation and differentiation, which reduces back-fat thickness of pigs. Taken together, the RES/LincRNA-ROFM/miR-133b/AdipoQ regulatory network preliminarily explains the mechanism of action of RES in inhibiting fat deposition, which provides new insight into the downstream mechanism of RES inhibition of fat deposits by regulating the lncRNA.

Deep Small RNA Sequencing Reveals Important miRNAs Related to Muscle Development and Intramuscular Fat Deposition in Longissimus dorsi Muscle From Different Goat Breeds

MicroRNAs (miRNAs) are a class of small non-coding RNAs that have been shown to play important post-transcriptional regulatory roles in the growth and development of skeletal muscle tissues. However, limited research into the effect of miRNAs on muscle development in goats has been reported. In this study, Liaoning cashmere (LC) goats and Ziwuling black (ZB) goats with significant phenotype difference in meat production performance were selected and the difference in Longissimus dorsi muscle tissue expression profile of miRNAs between the two goat breeds was then compared using small RNA sequencing. A total of 1,623 miRNAs were identified in Longissimus dorsi muscle tissues of the two goat breeds, including 410 known caprine miRNAs, 928 known species-conserved miRNAs and 285 novel miRNAs. Of these, 1,142 were co-expressed in both breeds, while 230 and 251 miRNAs were only expressed in LC and ZB goats, respectively. Compared with ZB goats, 24 up-regulated miRNAs and 135 miRNAs down-regulated were screened in LC goats. A miRNA-mRNA interaction network showed that the differentially expressed miRNAs would target important functional genes associated with muscle development and intramuscular fat deposition. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that the target genes of differentially expressed miRNAs were significantly enriched in Ras, Rap 1, FoxO, and Hippo signaling pathways. This study suggested that these differentially expressed miRNAs may be responsible for the phenotype differences in meat production performance between the two goat breeds, thereby providing an improved understanding of the roles of miRNAs in muscle tissue of goats.

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.

miR-F4-C12 Functions on the Regulation of Adipose Accumulation by Targeting PIK3R1 in Castrated Male Pigs

Simple Summary

MicroRNAs play crucial roles in regulating adipogenesis and fat storage; their role in regulating castrated male pig adipose growth is worth elucidating. Four nine-fold differentially expressed miRNAs were selected to investigate their functions on the regulation of adipose development based on our previous study. In 3T3-L1 cells and backfat tissues of castrated and intact male pigs, miR-F4-C12 was identified as involved in the adipose development using qRT-PCR and oil O staining. PIK3R1 was proposed by the TargetScan, miRDB and starBase as a target of miR-F4-C12 and verified through a dual-luciferase reporter assay and Western blot. These results revealed that miR-F4-C12 may regulate adipose accumulation in castrated male pigs by targeting PIK3R1. Our data provide a valuable foundation to understand the molecular mechanisms involved in adipose tissue metabolism to castration-induced sex hormone deficiency.

Abstract

MicroRNAs (miRNAs) constitute small regulatory molecules for a wide array of biological activities (18~24 nucleotides in length), including adipogenesis and adipose deposition. Their effect is, however, incompletely defined in inducing fat accumulation in castrated male pigs. Based on our study, four nine-times miRNAs were selected to examine their functions in adipose formation activities. In 3T3-L1 cells and backfat tissues of castrated and intact male pigs, miR-F4-C12 was identified as a factor in adipose development utilizing quantitative real-time PCR (qRT-PCR). Further, miR-F4-C12 was identified to promote fat development, suggesting that miR-F4-C12 was involved in adipogenesis. Moreover, phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1) was proposed by the TargetScan, miRDB and starBase as a target of miR-F4-C12 and verified through a two-luciferase reporter assay. The over-expression of miR-F4-C12 dramatically decreases the PIK3R1 protein level in 3T3-L1 cells. The mRNA and protein levels of PIK3R1 in castrated pigs are reduced relative to intact pigs, providing further evidence that PIK3R1 is involved in regulating adipose accumulation. These results suggest that miR-F4-C12 involves adipose development and may regulate subcutaneous adipose tissue accumulation by targeting PIK3R1 in castrated male pigs.

Blood-Brain Barrier Dysfunction in the Pathogenesis of Major Depressive Disorder

Major depression represents a complex and prevalent psychological disease that is characterized by persistent depressed mood, impaired cognitive function and complicated pathophysiological and neuroendocrine alterations. Despite the multifactorial etiology of depression, one of the most recent factors to be identified as playing a critical role in the development of depression is blood-brain barrier (BBB) disruption. The occurrence of BBB integrity disruption contributes to the disturbance of brain homeostasis and leads to complications of neurological diseases, such as stroke, chronic neurodegenerative disorders, neuroinflammatory disorders. Recently, BBB associated tight junction disruption has been shown to implicate in the pathophysiology of depression and contribute to increased susceptibility to depression. However, the underlying mechanisms and importance of BBB damage in depression remains largely unknown. This review highlights how BBB disruption regulates the depression process and the possible molecular mechanisms involved in development of depression-induced BBB dysfunction. Moreover, insight on promising therapeutic targets for treatment of depression with associated BBB dysfunctions are also discussed.

Palmitic Acid-Induced miR-429-3p Impairs Myoblast Differentiation by Downregulating CFL2

MicroRNAs are known to play a critical role in skeletal myogenesis and maintenance, and cofilin-2 (CFL2) is necessary for actin cytoskeleton dynamics and myogenic differentiation. Nonetheless, target molecules and the modes of action of miRNAs, especially those responsible for the inhibitory mechanism on the myogenesis by saturated fatty acids (SFA) or obesity, still remain unclear. Here, we reported the role played by miR-429-3p on CFL2 expression, actin filament dynamics, myoblast proliferation, and myogenic differentiation in C2C12 cells. Palmitic acid (PA), the most abundant SFA in diet, inhibited the myogenic differentiation of myoblasts, accompanied by CFL2 reduction and miR-429-3p induction. Interestingly, miR-429-3p suppressed the expression of CFL2 by targeting the 3'UTR of CFL2 mRNA directly. Transfection of miR-429-3p mimic in myoblasts increased F-actin formation and augmented nuclear YAP level, thereby promoting cell cycle progression and myoblast proliferation. Moreover, miR-429-3p mimic drastically suppressed the expressions of myogenic factors, such as MyoD, MyoG, and MyHC, and impaired myogenic differentiation of C2C12 cells. Therefore, this study unveiled the crucial role of miR-429-3p in myogenic differentiation through the suppression of CFL2 and provided implications of SFA-induced miRNA in the regulation of actin dynamics and skeletal myogenesis.

MicroRNA-126b-5p Exacerbates Development of Adipose Tissue and Diet-Induced Obesity

Obesity has become a worldwide epidemic, caused by many factors such as genetic regulatory elements, unhealthy diet, and lack of exercise. MicroRNAs (miRNAs) are non-coding single-stranded RNA classes, which are about 22 nucleotides in length and highly conserved among species. In the last decade, a series of miRNAs were identified as therapeutic targets for obesity. In the present study, we found that miR-126b-5p was associated with adipogenesis. miR-126b-5p overexpression promoted the proliferation of 3T3-L1 preadipocytes by upregulating the expression of proliferation-related genes and downregulating the expression of apoptosis-related genes; the inhibition of miR-126b-5p gave rise to opposite results. Similarly, miR-126b-5p overexpression could promote the differentiation of 3T3-L1 preadipocytes by increasing the expression of lipid deposition genes and triglyceride (TG) and total cholesterol (TC) levels. Moreover, luciferase reporter assay demonstrated that adiponectin receptor 2 (Adipor2) and acyl-CoA dehydrogenase, long chain (ACADL) were the direct target genes of miR-126b-5p. Moreover, overexpression of miR-126b-5p could exacerbate the clinical symptoms of obesity when mice were induced by a high-fat diet, including increased adipose tissue weight, adipocyte volume, and insulin resistance. Interestingly, overexpression of miR-126b-5p in preadipocytes and mice could significantly increase total fatty acid content and change the fatty acid composition of adipose tissue. Taken together, the present study showed that miR-126b-5p promotes lipid deposition in vivo and in vitro, indicating that miR-126b-5p is a potential target for treating obesity.

MicroRNA-200b Regulates the Proliferation and Differentiation of Ovine Preadipocytes by Targeting p27 and KLF9

Simple Summary

The miR-200b has been shown to play an important role in preadipocyte proliferation and differentiation. Herein, we explored the role of miR-200b in ovine adipocyte development, using Oil Red O staining, cell viability analysis, EdU and RT-qPCR. The results showed that miR-200b facilitated proliferation and suppressed the differentiation of preadipocytes. The dual fluorescent reporter vector experiments showed that miR-200b directly targeted p27 and KLF9. Meanwhile, we demonstrated that p27 significantly inhibited the proliferation, while KLF9 significantly promoted the differentiation of preadipocytes.

Abstract

MicroRNAs (miRNAs) are crucial regulatory molecules in lipid deposition and metabolism. However, the effect of miR-200b on the regulation of proliferation and adipogenesis of ovine preadipocytes is unknown in the sheep (Ovis aries). In this study, the expression profiles of miR-200b were investigated in the seven tissues of Tibetan ewes and differentiated preadipocytes. The effect of miR-200b, as well as its target genes p27 and KLF9, on the proliferation of ovine preadipocytes and adipogenesis was also investigated, using cell viability analysis, EdU staining, Oil Red O staining and reverse transcription-quantitative PCR (RT-qRCR). The miR-200b was expressed in all the tissues investigated, and it was highly expressed in lung, liver, subcutaneous adipose and spleen tissues. The expression of miR-200b continuously decreased when the differentiation of ovine preadipocytes initiated. The miR-200b mimic dramatically accelerated the proliferation but inhibited differentiation of ovine preadipocytes. The miR-200b inhibitor resulted in an opposite effect on the proliferation and differentiation of ovine preadipocytes. The dual luciferase reporter assay results showed that miR-200b mimic significantly decreased the luciferase activity of p27 and KLF9 in HEK293 cells transfected with wild-type dual luciferase reporter vectors. This suggests that p27 and KLF9 are the target genes of miR-200b. In over-expressed-p27 preadipocytes, the number of EdU-labeled preadipocytes and the expression levels of proliferation marker genes CDK2, CDK4, CCND1 and PCNA significantly decreased. In addition, the transfection of over-expressed-KLF9 vector into adipocytes remarkably increased the accumulation of lipid droplets and the expression levels of differentiation marker genes aP2, PPARγ, LPL and GLUT4. These results suggest that miR-200b accelerated the proliferation but inhibited the adipogenic differentiation of ovine preadipocytes by targeting p27 and KLF9, respectively.

TMT-based quantitative proteomics analysis reveals the key proteins related with the differentiation process of goat intramuscular adipocytes

Background

Intramuscular adipocytes differentiation is a complex process, which is regulated by various transcription factor, protein factor regulators and signal transduction pathways. However, the proteins and signal pathways that regulates goat intramuscular adipocytes differentiation remains unclear.

Result

In this study, based on nanoscale liquid chromatography mass spectrometry analysis (LC-MS/MS), the tandem mass tag (TMT) labeling analysis was used to investigate the differentially abundant proteins (DAPs) related with the differentiation process of goat intramuscular adipocytes. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes enrichment and protein-protein interaction network analyses were performed for the characterization of the identified DAPs. The candidate proteins were verified by parallel reaction monitoring analysis. As a result, a total of 123 proteins, 70 upregulation proteins and 53 downregulation proteins, were identified as DAPs which may be related with the differentiation process of goat intramuscular adipocytes. Furthermore, the cholesterol metabolism pathway, glucagon signaling pathway and glycolysis / gluconeogenesis pathway were noticed that may be the important signal pathways for goat Intramuscular adipocytes differentiation.

Conclusions

By proteomic comparison between goat intramuscular preadipocytes (P_IMA) and intramuscular adipocytes (IMA), we identified a series protein that might play important role in the goat intramuscular fat differentiation, such as SRSF10, CSRP3, APOH, PPP3R1, CRTC2, FOS, SERPINE1 and AIF1L, could serve as candidates for further elucidate the molecular mechanism of IMF differentiation in goats.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07730-y.

Integrated Genome-Wide Analysis of MicroRNA Expression Quantitative Trait Loci in Pig Longissimus Dorsi Muscle

Determining mechanisms regulating complex traits in pigs is essential to improve the production efficiency of this globally important protein source. MicroRNAs (miRNAs) are a class of non-coding RNAs known to post-transcriptionally regulate gene expression affecting numerous phenotypes, including those important to the pig industry. To facilitate a more comprehensive understanding of the regulatory mechanisms controlling growth, carcass composition, and meat quality phenotypes in pigs, we integrated miRNA and gene expression data from longissimus dorsi muscle samples with genotypic and phenotypic data from the same animals. We identified 23 miRNA expression Quantitative Trait Loci (miR-eQTL) at the genome-wide level and examined their potential effects on these important production phenotypes through miRNA target prediction, correlation, and colocalization analyses. One miR-eQTL miRNA, miR-874, has target genes that colocalize with phenotypic QTL for 12 production traits across the genome including backfat thickness, dressing percentage, muscle pH at 24 h post-mortem, and cook yield. The results of our study reveal genomic regions underlying variation in miRNA expression and identify miRNAs and genes for future validation of their regulatory effects on traits of economic importance to the global pig industry.

MiR-146a-5p targeting SMAD4 and TRAF6 inhibits adipogenensis through TGF-β and AKT/mTORC1 signal pathways in porcine intramuscular preadipocytes

BACKGROUND

Intramuscular fat (IMF) content is a vital parameter for assessing pork quality. Increasing evidence has shown that microRNAs (miRNAs) play an important role in regulating porcine IMF deposition. Here, a novel miRNA implicated in porcine IMF adipogenesis was found, and its effect and regulatory mechanism were further explored with respect to intramuscular preadipocyte proliferation and differentiation.

RESULTS

By porcine adipose tissue miRNA sequencing analysis, we found that miR-146a-5p is a potential regulator of porcine IMF adipogenesis. Further studies showed that miR-146a-5p mimics inhibited porcine intramuscular preadipocyte proliferation and differentiation, while the miR-146a-5p inhibitor promoted cell proliferation and adipogenic differentiation. Mechanistically, miR-146a-5p suppressed cell proliferation by directly targeting SMAD family member 4 (SMAD4) to attenuate TGF-β signaling. Moreover, miR-146a-5p inhibited the differentiation of intramuscular preadipocytes by targeting TNF receptor-associated factor 6 (TRAF6) to weaken the AKT/mTORC1 signaling downstream of the TRAF6 pathway.

CONCLUSIONS

MiR-146a-5p targets SMAD4 and TRAF6 to inhibit porcine intramuscular adipogenesis by attenuating TGF-β and AKT/mTORC1 signaling, respectively. These findings provide a novel miRNA biomarker for regulating intramuscular adipogenesis to promote pork quality.

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.

miR-429-3p/LPIN1 Axis Promotes Chicken Abdominal Fat Deposition via PPARγ Pathway

To explore the regulatory mechanism of abdominal fat deposition in broilers, 100-day-old Sanhuang chickens (n = 12) were divided into high-fat and low-fat groups, according to the abdominal fat ratio size. Total RNA isolated from the 12 abdominal fat tissues was used for miRNA and mRNA sequencing. Results of miRNA and mRNA sequencing revealed that miR-429-3p was highly expressed in high-fat chicken whereas LPIN1 expression was downregulated. Further, we determined that miR-429-3p promoted preadipocyte proliferation and differentiation, whereas LPIN1 exerted an opposite effect. Notably, we found that the miR-429-3p/LPIN1 axis facilitated PPARγ pathway activation, which is closely associated with the progression of adipogenesis. In conclusion, our results provide evidence that a novel miR-429-3p/LPIN1 axis is involved in the regulation of adipogenesis, which may have a guiding role in the improvement of breeding for abdominal fat traits in broiler chickens.

Identification of Candidate Circular RNAs Underlying Intramuscular Fat Content in the Donkey

Intramuscular fat (IMF) content is a crucial indicator of meat quality. Circular RNAs (circRNAs) are a large class of endogenous RNAs that are involved in many physiological processes. However, the expression and function of circRNA in IMF in the donkey remains unresolved. Here we performed an expression profiling of circRNAs in the donkey longissimus dorsi muscle and identified 12,727 candidate circRNAs. Among these, 70% were derived from the exons of protein genes. Furthermore, a total of 127 differentially expressed (DE) circRNAs were identified in high (H) and low (L) IMF content groups, including 63 upregulated and 64 downregulated circRNAs. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of the host genes of the DE circRNAs showed that the host genes were enriched in lipid metabolism related GO terms (e.g., fatty acid beta-oxidation using acyl-CoA dehydrogenase and MLL3/4 complex), and signaling pathways (e.g., TGF-beta and lysine degradation signaling pathway). Further analyses indicated that 127 DE circRNAs were predicted to potentially interact with miRNAs, leading to the construction of circRNA-miRNA regulatory network. Multiple circRNAs can potentially function as sponges of miRNAs that regulate the differentiation of adipocytes. Our results provide valuable expression profile information for circRNA in the donkey and new insight into the regulatory mechanisms of circRNAs in the regulation of IMF content.

New insights of Krüppel-like transcription factors in adipogenesis and the role of their regulatory neighbors

Obesity is a serious public health problem associated with predisposition to develop metabolic diseases. Over the past decade, several studies in vitro and in vivo have shown that the activity of Krüppel-like factors (KLFs) regulates adipogenesis, adipose tissue function and metabolism. Comprehension of both the origin and development of adipocytes and of adipose tissue could provide new insights into therapeutic strategies to contend against obesity and related metabolic diseases. This review focus on the transcriptional role that KLF family members play during adipocyte differentiation, describes their main interactions and the mechanisms involved in this fine-tuned developmental process. We also summarize new findings of the involvement of several effectors that modulate KLFs expression during adipogenesis, including growth factors, circadian clock proteins, interleukins, nuclear receptors, protein kinases and importantly, microRNAs. Thus, KLFs regulation by these factors and emerging molecules might constitute a potential therapeutic target for anti-obesity intervention.

Knockdown of KLF9 promotes the differentiation of both intramuscular and subcutaneous preadipocytes in goat

KLF9 is reported to promote adipocyte differentiation in 3T3-L1 cells and pigs. However, the roles of KLF9 in adipocytes differentiation of goat remain unknown. In this study, the expression profiles of KLF9 were different between subcutaneous and intramuscular preadipocytes of goat during differentiation process. After silencing KLF9 gene, the lipid droplets were increased in both two types of adipocytes. In subcutaneous preadipocyte with silencing KLF9, the expressions of C/EBPβ, PPARγ, LPL, KLF1-2, KLF5, and KLF17 genes were up-regulated, while KLF12, KLF4, and KLF13 genes were down-regulated in expression level. In intramuscular preadipocyte, aP2, C/EBPα, KLF2-3, KLF5, and KLF7 gene were up-regulated, and Pref-1 gene was down-regulated. In addition, the binding sites of KLF9 existed in the promoters of aP2, C/EBPα, C/EBPβ, LPL and Pref-1. Taken together, KLF9 play a negative role in the differentiation of both intramuscular and subcutaneous preadipocytes in goats, but the functional mechanism may be different.

miR-27a is an important adipogenesis regulator associated with differential lipid accumulation between intramuscular and subcutaneous adipose tissues of sheep

Micro ribonucleic acids (miRNAs) are crucial regulators for various biological processes. Despite important function in the proliferation and differentiation of preadipocytes, miRNA studies are limited in regional differences in adipogenesis. Here, we show that miR-27a plays an important role in regulating differential lipid accumulation between intramuscular (IM) and subcutaneous (SC) adipose tissues in sheep. Invivo, we observed that miR-27a expression in IM adipose tissue is more abundant than in SC adipose tissue. However, the expression of Peroxisome Proliferator-Activated Receptor Gamma (PPARG) and retinoid X receptor alpha (RXR alpha) in IM adipose tissue was significantly lower than that in SC adipose tissue. In the ovine preadipocyte differentiation model, we found that the expression of miR-27a was significantly decreased in differentiated ovine adipocytes. Overexpression of miR-27a significantly downregulated the expression of PPARG and RXR alpha and suppressed the accumulation of triglyceride but promoted the proliferation of ovine preadipocytes. Whereas, inhibition of miR-27a suppressed preadipocyte proliferation but enhanced PPARG and RXR alpha expression and lipid droplet formation. In addition, dual-luciferase activity assays showed that RXR alpha was a direct target of miR-27a. Thus, miR-27a enhances ovine preadipocytes proliferation and inhibits ovine preadipocytes differentiation through regulating the expression of target RXR alpha. Collectively, our study demonstrates the functional importance of miR-27a in ovine adipogenesis and provides novel insights into exploring regional differences in adipogenesis.

Circular RNA expression profiling in the fetal side of placenta from maternal polycystic ovary syndrome and circ_0023942 inhibits the proliferation of human ovarian granulosa cell

PURPOSE

Circular RNAs (circRNAs) are widely expressed noncoding RNAs which play important roles in various processes. The present study aimed to explore the effect of maternal PCOS on the expression of circRNAs in fetus and assessed the potential role of circRNA in human ovarian granulosa cell proliferation.

METHODS

Total RNA was extracted from the fetal side of placental tissues from maternal PCOS (n = 3) and healthy puerpera (n = 3) for circRNA microarray. Real-time reverse transcriptase quantitative PCR (RT-qPCR) was used to validate the microarray data in fetal side of placental tissues from puerpera with (n = 18) and without (n = 30) PCOS. Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were applied to predict the functions and pathways of circ_0023942 host genes. The circRNA-miRNA-mRNA network was constructed through bioinformatics prediction. Circ_0023942 overexpression vector was transiently transfected into human ovarian granulosa cell lines KGN and COV434. Cell proliferation was detected by cell counting kit-8. The protein expression level was determined by western blot.

RESULTS

Compared with healthy puerpera, 14 circRNAs were significantly upregulated and 101 circRNAs were significantly downregulated in the fetal side of placenta from maternal PCOS according to the microarray data. Six differentially expressed circRNAs were selected for validation by RT-qPCR, and the expression patterns of circ_0023942, circ_0002151, circ_0001274, and circ_0008514 were consistent with the microarray data. Circ_0023942 was chosen for further investigation. GO and KEGG analysis predicted that circ_0023942 participated in the regulation of developmental process and the MAPK signaling pathway. Seven miRNAs were predicted to be the targets of circ_0023942. Overexpression of circ_0023942 inhibited human ovarian granulosa cell proliferation and suppressed the expression of CDK-4.

CONCLUSION

Maternal PCOS impairs circ_0023942 expression in fetus. Overexpression of circ_0023942 inhibits human ovarian granulosa cell proliferation possibly via regulating CDK-4.

MicroRNA-200c-3p inhibits proliferation and migration of renal artery endothelial cells by directly targeting ZEB2

Continuous activation of angiotensin II (Ang II) induces renal vascular endothelial dysfunction, inflammation, and oxidative stress, all of which may contribute to renal damage. It is well established that microRNAs (miRNAs) play crucial regulatory roles in the pathogenesis of hypertensive renal damage. However, the detailed mechanisms and regulatory roles of miRNAs as therapeutic targets underlying Ang II-induced renal artery endothelial cell dysfunction in hypertensive renal damage have yet to be fully elucidated. The present study aimed to explore the expression status and putative role of miRNA-200c-3p in mediating the progression of hypertensive renal damage. We carried out real-time quantitative PCR (RT-qPCR) to detect the expression of miRNA-200c-3p in rat renal artery endothelial cells (RRAECs) induced by Ang II. MTT and transwell assays were utilized to evaluate the effects of miRNA-200c-3p on cell proliferation and migration, respectively. The present results revealed that the expression of miRNA-200c-3p was significantly upregulated in RRAECs exposed to Ang II compared with that of normal cells. miRNA-200c-3p overexpression markedly inhibited cell proliferation and migration of Ang II-induced RRAECs. Furthermore, bioinformatics predictions and dual-luciferase reporter assays indicated that zinc finger E-box-binding homeobox 2 (ZEB2) was a direct target gene of miRNA-200c-3p and that ZEB2 expression was inversely correlated with the levels of miRNA-200c-3p in RRAECs after exposure to Ang II. The effects of ZEB2 silencing were similar to the inhibitory effects observed following miRNA-200c-3p overexpression, and recovered ZEB2 expression reversed the anti-proliferative and anti-migratory influence of miRNA-200c-3p upregulation in RRAECs induced by Ang II. The present study indicated that miRNA-200c-3p might suppress the proliferation and migration of Ang II-induced RRAECs by targeting ZEB2. The miRNA-200c-3p/ZEB2 axis will provide valuable insights into the clinical management of hypertension-related kidney disease.

Upregulated microRNA-106a Promotes Porcine Preadipocyte Proliferation and Differentiation by Targeting Different Genes

Adipose tissue is one of the main organs for the energy storage and supply of organisms. Adipose deposition and metabolism are controlled by a cascade of transcription factors and epigenetic regulatory mechanisms. Previous studies have also shown that miR-106a plays a considerable role in the development of organisms. The regulatory mechanism of miR-106a on porcine preadipocytes is still not clear. In this study, preadipocytes were isolated from the neck subcutaneous deposits of 3–5-day old Chinese native Guanzhong black pigs using 5-ethynyl-20-deoxyuridine (EdU) staining and a CCK-8 assay to detect the number of proliferous cells and real-time qPCR (RT-qPCR) and western blot analysis to detect gene expression, as well as Oil Red O and BODIPY staining dye lipid droplets and flow cytometry (FCM) to detect cell cycles. We also used the double luciferase method to detect the relative luciferase activities. Upregulated miR-106a increased the number of proliferous cells and enhanced the expression of cell proliferation-related genes in porcine adipocytes. The double luciferase reporter vector confirmed that p21 was a target gene of miR-106a in the cell proliferation phase. miR-106a upregulation increased the number of lipid droplets and the expression of lipogenic genes and directly targeted BMP and activin membrane-bound inhibitor (BAMBI) in the process of differentiation. Our results indicated that miR-106a promotes porcine preadipocyte proliferation and differentiation by targeting p21 and BAMBI.

Mir-152 Regulates 3T3-L1 Preadipocyte Proliferation and Differentiation

Adipogenesis is a complex biological process and the main cause of obesity. Recently, microRNAs (miRNAs), a class of small endogenous non-coding RNAs, have been proven to play an important role in adipogenesis by the post-transcriptional regulation of target genes. In this current study, we observed an increment of miR-152 expression during the process of 3T3-L1 cell audiogenic differentiation. A functional analysis indicated that the overexpression of miR-152 inhibited pre-adipocyte proliferation and suppressed the expression of some cell cycle-related genes. Moreover, the overexpression of miR-152 promoted lipid accumulation in 3T3-L1 preadipocytes accompanied by increase of the expression of some pro-audiogenic genes. Additionally, a dual-luciferase reporter assay demonstrated lipoprotein lipase (LPL) was a direct target gene of miR-152 during preadipocyte differentiation. Further analysis showed that miR-152 was positively correlated with adipogenesis and intramuscular fat formation in vivo. Taken together, our findings suggest that miR-152 could suppress 3T3-L1 preadipocyte proliferation, whereas it could promote 3T3-L1 preadipocyte differentiation by negatively regulating LPL. The findings indicate that miR-152 might have a therapeutic significance for obesity and obesity-related metabolic syndrome.

MicroRNA-338-3p suppresses cell proliferation, migration and invasion in human malignant melanoma by targeting MACC1

Malignant melanoma (MM) is the most aggressive form of skin cancer originating from melanocytes with increased proliferative and metastatic ability. Previous studies have revealed that microRNA-338-3p (miR-338-3p) functions as a tumor suppressor in several types of cancer, including cervical cancer, renal cell carcinoma and thyroid cancer. However, the function and mechanism underlying the action of miR-383-3p in MM remain unclear. In the study, aberrant downregulation of miR-338-3p was observed in 60 pairs of MM and adjacent non-tumor tissue using quantitative polymerase chain reaction assay. Decreased miR-383-3p expression was associated with advanced clinical stage (P<0.05) and lymph node metastasis (P<0.001). The overexpression of miR-338-3p in A375 and G361 cells suppressed cell proliferation and migration using MTT, colony formation, wound healing and transwell assays. Mechanistically, MACC1 was identified as a direct target for miR-338-3p using bioinformatics prediction and dual-luciferase assays. Furthermore, MACC1 expression was significantly increased and inversely correlated with the levels of miR-338-3p in MM tissues. More importantly, restoration of MACC1 resulted in reversed the inhibitory effects of miR-338-3p overexpression on MM cells by altering the expression levels of PCNA and epithelial-mesenchymal transition (EMT)-associated proteins. These results suggest that miR-338-3p functions as a novel tumor suppressor, at least in part, via targeting MACC1 and suggest that miR-338-3p may serve as a potential target for treatment of MM patients.

DNA methylome profiling in identical twin pairs discordant for body mass index

OBJECTIVE

Body mass index (BMI) serves as an important measurement of obesity and adiposity, which are highly correlated with cardiometabolic diseases. Although high heritability has been estimated, the identified genetic variants by genetic association studies only explain a small proportion of BMI variation. As an active effort for further exploring the molecular basis of BMI variation, large-scale epigenome-wide association studies have been conducted but with limited number of loci reported, perhaps due to poorly controlled confounding factors, including genetic factors. Being genetically identical, monozygotic twins discordant for BMI are ideal subjects for analyzing the epigenetic association between DNA methylation and BMI, providing perfect control on their genetic makeups largely responsible for BMI variation.

SUBJECTS

We performed an epigenome-wide association study on BMI using 30 identical twin pairs (15 male and 15 female pairs) with age ranging from 39 to 72 years and degree of BMI discordance ranging from 3-7.5 kg/m². Methylation data from whole blood samples were collected using the reduced representation bisulfite sequencing technique.

RESULTS

After adjusting for blood cell composition and clinical variables, we identified 136 CpGs with p-value < 1e-4, 30 CpGs with p < 1e-05 but no CpGs reached genome-wide significance. Genomic region-based analysis found 11 differentially methylated regions harboring coding and non-coding genes some of which were validated by gene expression analysis on independent samples.

CONCLUSIONS

Our DNA methylation sequencing analysis on identical twins provides new references for the epigenetic regulation on BMI and obesity.

Loss of m6 A on FAM134B promotes adipogenesis in porcine adipocytes through m6 A-YTHDF2-dependent way

N⁶ -methyladenosine (m⁶ A) mRNA modification plays an important role in adipogenesis, but its role on single gene remains unexplored. Family with Sequence Similarity 134, Member B (FAM134B) is a cis-Golgi transmembrane protein that known to be necessary for the long-term survival of nociceptive and autonomic ganglion neurons. Recent work has shown that FAM134B plays a pivotal role in lipid homeostasis and was identified as its significant m⁶ A level difference between Chinese local Jinhua pigs and Landrace through RNA-sequence. Here, we construct the non-m⁶ A FAM134B coding sequence (CDS) plasmid (FAM134B-MUT) and found one important m⁶ A site on its CDS. Expression of FAM134B-MUT was more effective in promoting porcine preadipocytes adipogenic differentiation and lipid deposition than wild-type FAM134B (FAM134B-WT) both in early and ultimate differentiation stage. FAM134B-MUT functions better in promoting fat deposition by upregulating peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein (C/EBPα) level. The m⁶ A reader protein YTH m⁶ A RNA binding protein 2 (YTHDF2) interacts with FAM134B mRNA and down regulated its protein level. These results demonstrate that FAM134B was the target of YTHDF2, which may recognize and binds the m⁶ A site of FAM134B to reduce its mRNA lifetime and reduce its protein abundance. © 2018 IUBMB Life, 71(5):580-586, 2019.

MicroRNA-214-3p Targeting Ctnnb1 Promotes 3T3-L1 Preadipocyte Differentiation by Interfering with the Wnt/β-Catenin Signaling Pathway

Differentiation from preadipocytes into mature adipocytes is a complex biological process in which miRNAs play an important role. Previous studies showed that miR-214-3p facilitates adipocyte differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) in vitro. The detailed function and molecular mechanism of miR-214-3p in adipocyte development is unclear. In this study, the 3T3-L1 cell line was used to analyze the function of miR-214-3p in vitro. Using 5-Ethynyl-2′-deoxyuridine (EdU) staining and the CCK-8 assay, we observed that transfection with the miR-214-3p agomir visibly promoted proliferation of 3T3-L1 preadipocytes by up-regulating the expression of cell cycle-related genes. Interestingly, overexpression of miR-214-3p promoted 3T3-L1 preadipocyte differentiation and up-regulated the expression of key genes for lipogenesis: PPARγ, FABP4, and Adiponectin. Conversely, inhibition of miR-214-3p repressed 3T3-L1 preadipocyte proliferation and differentiation, and down-regulated the expression of cell cycle-related genes and adipogenic markers. Furthermore, we proved that miR-214-3p regulates 3T3-L1 preadipocyte differentiation by directly targeting the 3′-untranslated regions (3′UTR) of Ctnnb1, which is an important transcriptional regulatory factor of the Wnt/β-Catenin pathway. Taken together, the data indicate that miR-214-3p may positively regulate preadipocyte proliferation and enhance differentiation through the Wnt/β-Catenin signaling pathway.

MTCH2 promotes adipogenesis in intramuscular preadipocytes via an m6A-YTHDF1-dependent mechanism

Intramuscular fat is considered a potential factor that is associated with meat quality in animal production and insulin resistance in humans. N⁶-methyladenosine (m⁶A) modification of mRNA plays an important role in regulating adipogenesis. However, the effects of m⁶A on the adipogenesis of intramuscular preadipocytes and associated mechanisms remain unknown. Here, we performed m⁶A sequencing to compare m⁶A methylome of the longissimus dorsi muscles (LDMs) between Landrace pigs (lean-type breed) and Jinhua pigs (obese-type breed with higher levels of intramuscular fat). Transcriptome-wide m⁶A profiling of porcine LDMs was highly conserved with humans and mice. Furthermore, we identified a unique methylated gene in Jinhua pigs named mitochondrial carrier homology 2 ( MTCH2). The m⁶A levels of MTCH2 mRNA were reduced by introducing a synonymous mutation, and adipogenesis test results showed that the MTCH2 mutant was inferior with regard to adipogenesis compared with the MTCH2 wild-type. We then found that MTCH2 protein expression was positively associated with m⁶A levels, and an YTH domain family protein 1-RNA immunoprecipitation-quantitative PCR assay indicated that MTCH2 mRNA was a target of the YTH domain family protein 1. This study provides comprehensive m⁶A profiles of LDM transcriptomes in pigs and suggests an essential role for m⁶A modification of MTCH2 in intramuscular fat regulation.-Jiang, Q., Sun, B., Liu, Q., Cai, M., Wu, R., Wang, F., Yao, Y., Wang, Y., Wang, X. MTCH2 promotes adipogenesis in intramuscular preadipocytes via an m⁶A-YTHDF1-dependent mechanism.

MiR-200a inhibits cell proliferation and EMT by down-regulating the ASPH expression levels and affecting ERK and PI3K/Akt pathways in human hepatoma cells

The primary objective of this study was to investigate the role of miR-200a in cell proliferation and epithelial-mesenchymal transition (EMT) through regulating targeting aspartate-β-hydroxylase (ASPH), which may further affect the activation of ERK/PI3K/Akt pathway. Liver cancer and adjacent tissues were collected from 72 cases of liver cancer patients with surgery in our hospital. In this study, the mRNA expression level of miR-200a was significantly decreased by real-time PCR (RT-PCR) detection. ASPH expressions, however, had an opposite tendency compared to that of miR-200a. We found a significantly negative correlation between miR-200a expressions and ASPH expressions. The survival rate of liver cancer patients with the low expressed ASPH was significantly higher than those with the high expressed ASPH. RT-PCR and Western blot results showed that low expressed miR-200a and highexpressed ASPH were found in liver cancer cell lines. Further research discovered that miR-200a transfection could significantly decrease the relative luciferase activity when it was integrated with ASPH 3'-untranslated region (3'-UTR) in HepG2 cells. Cell Counting Kit (CCK-8) detection showed that treatment with miR-200a mimics reduced cell viability, while the over-expressed ASPH increased cell viability by regulating the c-mycmrna (c-Myc) and Cyclin-D1 expressions. The EMT-related genes including E-Cadherin, N-Cadherin and Vimentin expressions were significantly increased, whereas the over-expressed ASPH exerted the opposite effects. In addition, extracellular signal regulated kinase (ERK), phosphoinositide-3-kinase (PI3K) and serine threonine kinase (AKT) were suppressed by miR-200a mimics. In conclusion, miR-200a inhibits cell proliferation and EMT in human hepatoma cells by targeting ASPH and affecting ERK and PI3K/Akt signaling pathways.

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

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

Long Non-coding RNA XIST Promotes Glioma Tumorigenicity and Angiogenesis by Acting as a Molecular Sponge of miR-429

Glioma is a worldwide malignancy, which displays significantly active metastasis and angiogenesis. Interaction between long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) has been shown to play crucial role in regulating tumor properties. However, the potential of lncRNA X-inactive specific transcript (XIST) to function as a miRNA regulator and its relevance in glioma tumorigenicity and angiogenesis have so far remained unclear. Expression analysis of lncRNA XIST in glioma cells revealed its significant up-regulation. Interestingly, silencing of XIST repressed both metastatic and pro-angiogenic ability in vitro as well as in vivo. Subsequent studies revealed that lncRNA XIST expression inversely correlated with miR-429 expression in glioma cells; miR-429 modulated XIST expression by directly targeting the XIST gene sequence. In addition, miR-429 inhibitor restored metastatic and pro-angiogenic ability of gliomas abolished by silencing XIST. Our data provide insight into the key roles of the lncRNA-miRNA functional network in gliomas, which can aid in developing new therapeutic strategies for gliomas through clinical trials.

miR-425-5p Inhibits Differentiation and Proliferation in Porcine Intramuscular Preadipocytes

Intramuscular fat (IMF) content affects the tenderness, juiciness, and flavor of pork. An increasing number of studies are focusing on the functions of microRNAs (miRs) during porcine intramuscular preadipocyte development. Previous studies have proved that miR-425-5p was enriched in porcine skeletal muscles and played important roles in multiple physiological processes; however, its functions during intramuscular adipogenesis remain unclear. To explore the role of miR-425-5p in porcine intramuscular adipogenesis, miR-425-5p agomir and inhibitor were used to perform miR-425-5p overexpression and knockdown in intramuscular preadipocytes, respectively. Our results showed that the agomir of miR-425-5p dramatically inhibited intramuscular adipogenic differentiation and downregulated the expression levels of adipogenic marker genes PPARγ, FABP4, and FASN, whereas its inhibitor promoted adipogenesis. Interestingly, the agomir repressed proliferation of porcine intramuscular preadipocytes by downregulation of cyclin B and cyclin E. Furthermore, we demonstrated that miR-425-5p inhibited adipogenesis via targeting and repressing the translation of KLF13. Taken together, our findings identified that miR-425-5p is a novel inhibitor of porcine intramuscular adipogenesis possibly through targeting KLF13 and subsequently downregulating PPARγ.