ssc-miR-451 Regulates Porcine Primary Adipocyte Differentiation by Targeting ACACA

Characteristics of microRNAs in Skeletal Muscle of Intrauterine Growth-Restricted Pigs

microRNAs are a class of small RNAs that have been extensively studied, which are involved in many biological processes and disease occurrence. The incidence of intrauterine growth restriction is higher in mammals, especially multiparous mammals. In this study, we found that the weight of the longissimus dorsi of intrauterine growth-restricted pigs was significantly lower than that of normal pigs. Then, intrauterine growth-restricted pig longissimus dorsi were used to characterize miRNA expression profiles by RNA sequencing. A total of 333 miRNAs were identified, of which 26 were differentially expressed. Functional enrichment analysis showed that these differentially expressed miRNAs regulate the expression of their target genes (such as PIK3R1, CCND2, AKT3, and MAP3K7), and these target genes play an important role in the proliferation and differentiation of skeletal muscle through signaling pathways such as the PI3K-Akt, MAPK, and FoxO signaling pathways. Furthermore, miRNA-451 was significantly upregulated in IUGR pig skeletal muscle. Overexpression of miR-451 in C2C12 cells significantly promoted the expression of Mb, Myod, Myog, Myh1, and Myh7, suggesting that miR-451 may be involved in the regulation of the myoblastic differentiation of C2C12 cells. Our results reveal the role of miRNA-451 in regulating myogenic differentiation of skeletal muscle in pigs with intrauterine growth restriction.

Comprehensive Analysis of the Longissimus Dorsi Transcriptome and Metabolome Reveals the Regulatory Mechanism of Different Varieties of Meat Quality

The beef quality significantly varies between breeds. Pingliang Red Cattle resembles Wagyu in fat deposition and flavor. To screen key factors affecting beef quality, we performed meat quality trait testing, RNA-seq, and metabolomics on the longissimus dorsi of Pingliang Red Cattle, Wagyu cross F1 generation, and Simmental cattle. The gene and metabolite expression profiles were similar between Pingliang Red Cattle and Wagyu cross F1 generation. Genes such as FASN, ACACA, PLIN1, and FABP4 were significantly upregulated in the Pingliang Red Cattle and Wagyu cross F1 generation (P < 0.05). Similarly, numerous metabolites, such as 3-iodo-l-tyrosine, arachidonic acid, and cis-aconitate, which may improve the beef quality such as fat deposition and tenderness, were found in higher levels in the Pingliang Red Cattle and Wagyu cross F1 generation. This study revealed differences in the transcriptional and metabolic levels between Pingliang Red Cattle and premium beef breeds, suggesting that Pingliang Red Cattle harbors the genetic potential for breeding high-grade beef cattle.

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.

Novel Insights into the Differences in Nutrition Value, Gene Regulation and Network Organization between Muscles from Pasture-Fed and Barn-Fed Goats

The physiological and biochemical characters of muscles derived from pasture-fed or barn-fed black goats were detected, and RNA-seq was performed to reveal the underlying molecular mechanisms to identify how the pasture feeding affected the nutrition and flavor of the meat. We found that the branched chain amino acids, unsaturated fatty acids, and zinc in the muscle of pasture-fed goats were significantly higher than those in the barn-fed group, while the heavy metal elements, cholesterol, and low-density lipoprotein cholesterol were significantly lower. RNA-seq results showed that 1761 genes and 147 lncRNA transcripts were significantly differentially expressed between the pasture-fed and barn-fed group. Further analysis found that the differentially expressed genes were mainly enriched in the myogenesis and Glycerophospholipid metabolism pathway. A functional analysis of the lncRNA transcripts further highlighted the difference in fatty acid metabolism between the two feeding models. Our study provides novel insights into the gene regulation and network organization of muscles and could be potentially used for improving the quality of mutton.

miR-152 targets pyruvate kinase to regulate the glycolytic activity of pig skeletal muscles and affects pork quality

As a type of non-coding RNA, microRNAs are widely involved in the biological processes of animals. In the present study, the expression of miR-152 in glycolytic muscle fibers (Longissimus thoracis, LT) was lower than that of oxidative muscle fibers (Psoas major, PM). Using dual luciferase assay, miR-152 was shown to target muscle pyruvate kinase (PKM) to perform biological functions. Moreover, overexpression of miR-152 in primary porcine cells inhibited PKM gene expression and reduced lactic acid production in cells, whereas inhibition of miR-152 expression promoted PKM gene expression and increased lactic acid production. Correlation analysis showed that the expression of miR-152 was significantly positively correlated with the ultimate pH of LT after slaughter, while the expression of the PKM gene was significantly negatively correlated with the final pH of LT. In vivo and in vitro experiments discussed herein suggest that miR-152 may affect muscle pH by targeting the expression of the PKM gene. Our findings enrich the understanding of the genetic regulatory network that influences pork quality.