MiR-99b-5p Attenuates Adipogenesis by Targeting SCD1 and Lpin1 in 3T3-L1 Cells

Characterization and Function Analysis of miRNA Editing during Fat Deposition in Chinese Indigenous Ningxiang Pigs

This study aimed to identify active miRNA editing sites during adipose development in Ningxiang pigs and analyze their characteristics and functions. Based on small RNA-seq data from the subcutaneous adipose tissues of Ningxiang pigs at four stages-30 days (piglet), 90 days (nursery), 150 days (early fattening), and 210 days (late fattening)-we constructed a developmental map of miRNA editing in the adipose tissues of Ningxiang pigs. A total of 505 miRNA editing sites were identified using the revised pipeline, with C-to-U editing types being the most prevalent, followed by U-to-C, A-to-G, and G-to-U. Importantly, these four types of miRNA editing exhibited base preferences. The number of editing sites showed obvious differences among age groups, with the highest occurrence of miRNA editing events observed at 90 days of age and the lowest at 150 days of age. A total of nine miRNA editing sites were identified in the miRNA seed region, with significant differences in editing levels (p < 0.05) located in ssc-miR-23a, ssc-miR-27a, ssc-miR-30b-5p, ssc-miR-15a, ssc-miR-497, ssc-miR-15b, and ssc-miR-425-5p, respectively. Target gene prediction and KEGG enrichment analyses indicated that the editing of miR-497 might potentially regulate fat deposition by inhibiting adipose synthesis via influencing target binding. These results provide new insights into the regulatory mechanism of pig fat deposition.

Alternative Polyadenylation of Malic Enzyme 1 Is Essential for Accelerated Adipogenesis

Understanding the mechanism of adipogenesis is an important basis for improving meat quality traits of livestock. Alternative polyadenylation (APA) is a vital mechanism to regulate the expression of eukaryotic genes. However, how the individual APA functions in adipogenesis remains elusive. This study was intended to investigate the effect of malic enzyme 1 (ME1) APA on adipogenesis. Here, intracellular lipid droplets were stained using Oil red O. 3' RACE was used to verify APA events of the ME1 gene. Interactions between ME1 3' untranslated region (3' UTR)-APA isoforms and miRNAs, as well as differential expression of isoforms, were examined using dual-luciferase reporter and molecular experiments. The mechanism of ME1 APA on adipogenesis was explored by gain and loss of function assays. In this study, two ME1 isoforms with different 3' UTR lengths were detected during adipogenesis. Moreover, the ME1 isoform with a short 3' UTR was significantly upregulated compared with the one with a long 3' UTR. Mechanistically, only the long ME1 isoform was targeted by miR-153-3p to attenuate adipogenesis, while the short one escaped the regulation of miR-153-3p to accelerate adipogenesis. Our results reveal a novel mechanism of ME1 APA in regulating adipogenesis.

Childhood obesity, metabolic syndrome, and oxidative stress: microRNAs go on stage

The incidence of childhood obesity and metabolic syndrome has grown notably in the last years, becoming major public health burdens in developed countries. Nowadays, oxidative stress is well-recognized to be closely associated with the onset and progression of several obesity-related complications within the framework of a complex crosstalk involving other intertwined pathogenic events, such as inflammation, insulin disturbances, and dyslipidemia. Thus, understanding the molecular basis behind these oxidative dysregulations could provide new approaches for the diagnosis, prevention, and treatment of childhood obesity and associated disorders. In this respect, the transcriptomic characterization of miRNAs bares great potential because of their involvement in post-transcriptional modulation of genetic expression. Herein, we provide a comprehensive literature revision gathering state-of-the-art research into the association between childhood obesity, metabolic syndrome, and miRNAs. We put special emphasis on the potential role of miRNAs in modulating obesity-related pathogenic events, with particular focus on oxidative stress.

Rosiglitazone-induced PPARγ activation promotes intramuscular adipocyte adipogenesis of pig

Intramuscular fat (IMF) positively influences various aspects of meat quality, while the subcutaneous fat (SF) has negative effect on carcass characteristics and fattening efficiency. Peroxisome proliferator-activated receptor gamma (PPARγ) is a key regulator of adipocyte differentiation, herein, through bioinformatic screen for the potential regulators of adipogenesis from two independent microarray datasets, we identified that PPARγ is a potentially regulator between porcine IMF and SF adipogenesis. Then we treated subcutaneous preadipocytes (SA) and intramuscular preadipocytes (IMA) of pig with RSG (1 µmol/L), and we found that RSG treatment promoted the differentiation of IMA via differentially activating PPARγ transcriptional activity. Besides, RSG treatment promoted apoptosis and lipolysis of SA. Meanwhile, by the treatment of conditioned medium, we excluded the possibility of indirect regulation of RSG from myocyte to adipocyte and proposed that AMPK may mediate the RSG-induced differential activation of PPARγ. Collectively, the RSG treatment promotes IMA adipogenesis, and advances SA lipolysis, this effect may be associated with AMPK-mediated PPARγ differential activation. Our data indicates that targeting PPARγ might be an effective strategy to promote intramuscular fat deposition while reduce subcutaneous fat mass of pig.

Blockage of NDUFB9-SCD1 pathway inhibits adipogenesis : Blockage of NDUFB9-SCD1 pathway inhibits adipogenesis

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease with an increasing global prevalence associated with tremendous clinical, economic, and health-related quality-of-life burden. Currently, no effective pharmacological therapy is available for NAFLD. Adipogenesis process is accompanied by fat synthesis which may participate in the occurrence and development of NAFLD. Despite intensive investigations, numerous mechanistic aspects of adipogenesis remain unclear and many potential therapeutic targets are yet to be discovered.In this study, the transcriptomics and lipidomics approaches were used to explore the functional genes regulating adipogenesis and the potential mechanism in OP9 cells and adipose-derived stem cells.We find that NADH:ubiquinone oxidoreductase subunit b9 (Ndufb9) is up-regulated in adipogenesis (p < 0.001), and silencing Ndufb9 (83% silencing efficiency) inhibits adipogenesis. The effect of Ndufb9 is mediated through stearoyl-CoA desaturase 1 (Scd1). Aramchol, a SCD1 inhibitor, significantly blocks adipogenesis (markedly TG decrease, p < 0.001).Our study broadens the understanding of the role of Ndufb9 in adipogenesis and provides a new target for the treatment of NAFLD.

Ndufa6 regulates adipogenic differentiation via Scd1

Obesity and associated complications are becoming a pandemic. Inhibiting adipogenesis is an important intervention for the treatment of obesity. Despite intensive investigations, numerous mechanistic aspects of adipogenesis remain unclear, and many potential therapeutic targets have yet to be discovered. Transcriptomics and lipidomics approaches were used to explore the functional genes regulating adipogenic differentiation and the potential mechanism in OP9 cells and adipose-derived stem cells. In this study, we found that NADH:ubiquinone oxidoreductase subunit A6 (Ndufa6) participates in the regulation of adipogenic differentiation. Furthermore, we show that the effect of Ndufa6 is mediated through stearoyl-CoA desaturase 1 (Scd1) and demonstrate the inhibitory effect of a SCD1 inhibitor on adipogenesis. Our study broadens the understanding of adipogenic differentiation and offers NDUFA6-SCD1 as a potential therapeutic target for the treatment of obesity.

Shortening of HO1 3'UTRs by Alternative Polyadenylation Suppresses Adipogenesis in 3T3-L1

Appropriately increasing intramuscular fat content can help improve meat quality, so it is necessary to explore the internal molecular mechanism of preadipocyte differentiation. The role of heme oxygenase 1 (HO1) in cell oxidative stress, energy metabolism, cell proliferation, and differentiation has gradually been revealed. Here, we used 3'RACE to identify the full-length 3' untranslated region (3'UTR) of HO1 and found that a very short 3'UTR variant was produced by alternative polyadenylation (APA). HO1 with a long 3'UTR variant was identified as a direct target of miR155-5P and miR377-3P. Our experimental results verified the inhibitory effect of HO1 on preadipocyte differentiation. In addition, our research confirms that by escaping microRNA inhibitory effects, the HO1 3'UTR short variant produced by APA has a higher level of expression. Thus, the HO1 3'UTR short variant has a stronger inhibitory effect on the preadipocyte differentiation than the HO1 3'UTR long variants in 3T3-L1.