Mammalian skeletal muscles comprise different types of muscle fibers, and this muscle fiber heterogeneity is generally characterized marked by the expression of myosin heavy chain (MyHC) isoforms. A INTRODUCTIONhttps://www.jbc.org/cgi/
miRNAs, a kind of noncoding small RNA, play a significant role in adipose differentiation.In this study, we explored the effect of miR-324-5p in adipose differentiation, and found that miR-324-5p could promote adipocytes differentiation and increase body weight in mice. We overexpressed miR-324-5p during adipocytes differentiation, by oil red O and bodipy staining found that lipid accumulation was increased, and the expression level of adipogenic related genes were significantly increased. And the opposite experimental results were obtained after inhibiting miR-324-5p. In vivo, we injected miR-324-5p ago-miR in obese mice and found that body weight, adipocyte area, and adipogenic-related gene expression level were significantly increased but lipolytic genes were decreased. To further explore the mechanism of miR-324-5p regulation in lipid accumulation, we constructed Krueppel-like factor 3 (KLF3) 3′-untranslated region luciferase reporter vector and KLF3 pcDNA 3.1 overexpression vector, and found that miR-324-5p was able to directly target KLF3. Overall, in this study we found that miR-324-5p could promote mice preadipoytes differentiation and increase mice fat accumulation by targeting KLF3.
Fermentation has attracted increasing attention in pig industry, because of low costs and numerous benefits on pig growth and health as well as environmental improvement, although the mechanisms remain largely unknown. In the present study, fermented corn-soybean meal significantly improved average daily gain and gain:food ratio (P < 0.05). Fermented feed (FF) significantly increased insulin-like growth factor 1 (IGF1) transcription in liver (P < 0.05). Meanwhile, fermented meal significantly enhanced the binding of CCAAT/enhancer-binding protein beta (C/EBPβ) to IGF1 promoter and C/EBPβ expression in liver (both P < 0.05). FF tended to increase IGF1 proteins in liver and serum too (both 0.05 < P < 0.10). Meanwhile, FF slightly but significantly increased hepatic and circulating triglyceride and total cholesterol levels, as well as serum ratio of high-density to low-density cholesterol (all P < 0.05). Our data indicated that FF could significantly augment the binding of C/EBPβ to IGF1 promoter and promote hepatic IGF1 expression and production, thus boost pig growth.
miRNAs are a small class of noncoding RNAs that perform biological functions by regulating the stability or translation of target genes in various biological processes. This study illustrated the role of miR-10a-5p, which is relatively enriched in adipose tissues, using primary mouse preadipocytes as model. With elevated miR-10a-5p expression, the proliferative ability of mouse preadipocytes was significantly enhanced, indicated by increased EdU+ cells and G1/S transition, accompanied by upregulated Cyclin B, Cyclin D and PCNA and downregulated p21 and p27. Meanwhile, the adipogenic differentiation was significantly attenuated by elevated miR-10a-5p, supported by Oil Red O staining and suppressed PPARγ and aP2 expression. Furthermore, Map2k6 and Fasn were predicted to be the target genes of miR-10a-5p in silico, and dual luciferase reporter assay confirmed the direct targeting effects. Western blot analysis results showed that miR-10a-5p specially reduced Map2k6 expression at the proliferative stage without affecting Fasn expression, while significantly restrained Fasn expression with unchanged Map2k6 expression during adipogenic differentiation. Taken together, these results revealed a potential role of miR-10a-5p in adipogenesis and in the treatment of obesity.
Elucidation of the complex regulation of porcine muscle development is key to increasing pork output and improving pork quality. However, the molecular mechanisms involved in early porcine embryonic muscle development in different pig breeds remain largely unknown. Here, GC–MS based metabolomics and metabolomic profiling was used to examine the longissimus lumborum (LL) of the Lantang (LT) and the Landrace (LR) pig at embryonic day 35 (E35). Metabolites showed clear separation between LT and LR, with 40 metabolites having higher abundances in LT and 14 metabolites having lower abundances in LT compared with LR. In addition, these metabolic changes were mainly associated with nucleotide metabolism and energy metabolism, such as purine metabolism, pyrimidine metabolism, the pentose phosphate pathway, and the TCA cycle. More interestingly, the contents of DNA, RNA, and ATP per unit mass of LL tissues were higher in LT, indicating rapid synthesis of nucleic acids and ATP, to meet both the material and energy requirements of rapid cell proliferation and differentiation. Furthermore, enzyme activity associated with the TCA cycle and pentose phosphate pathway, including α-ketoglutaric dehydrogenase (KGDH), malate dehydrogenase (MDH), pyruvate dehydrogenase (PDH), succinate dehydrogenase (SDH), and glucose-6-phosphate dehydrogenase (G6PDH), were higher in LT. Based on these results, we conclude that there are significant differences in nucleotide metabolism and energy metabolism of LL between LT and LR, and we speculate that the enhanced nucleic acid metabolism and energy metabolism in LT can meet the material and energy requirements of rapid cell proliferation and differentiation, making myogenesis more intense in LT compared to LR which might be the metabolic mechanism underlying the distinct skeletal muscle development in the two breeds.
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