Profiling and characterization of miRNAs associated with intramuscular fat content in Yorkshire pigs

Identification of Key Genes Related to Intramuscular Fat Content of Psoas Major Muscle in Saba Pigs by Integrating Bioinformatics and Machine Learning Based on Transcriptome Data

The psoas major muscle (PMM) is a piece of pork with good tenderness and high value. Intramuscular fat (IMF) content, serving as a pivotal indicator of pork quality, varies greatly among pigs within the same breed. However, there is a paucity of studies focusing on investigating the molecular mechanism of PMM IMF deposition in the same pig breed. The present study aimed to identify the potential genes related to the IMF content of PMM in low- and high-IMF Saba pigs based on transcriptome data analysis. The data used in this study were the RNA sequences of PMM from 12 Saba pigs (PRJNA1223630, from our laboratory) and gene expression profiles (GSE207279) acquired from the NCBI Sequence Read Archive database and the GEO database, respectively, together with data on the fatty acid and amino acid composition of the 12 Saba pigs' PMM. It was found that the high-IMF pigs exhibited significantly elevated levels of saturated fatty acids and (mono)unsaturated fatty acids, especially C14:0, C16:0, C20:0, C16:1, C18:1n9c, and C20:2, compared with those in the low-IMF pigs (p < 0.05 or p < 0.01). A total of 370 differentially expressed genes (DEGs) (221 up- and 149 down-regulated) were identified based on PRJNA1223630. Then, 20 hub genes were identified through protein-protein interaction (PPI) network analysis. Four potential fat-deposition-related genes (DGAT2, PCK1, MELK, and FASN) were further screened via the intersection of the candidate genes identified by the Least Absolute Shrinkage and Selection Operator (LASSO) algorithm and the top five genes ranked by the Random Forest (RF) method based on the 20 hub genes and were validated in the test gene set (GSE207279). The constructed mRNA (gene)-miRNA-lncRNA network, involving miRNAs (miR-103a-3p, miR-107, and miR-485-5p), lncRNAs (XIST, NEAT1, and KCNQ1OT1), and FASN, might be crucial for IMF deposition in pigs. These findings might delineate valuable regulatory molecular mechanisms coordinating IMF deposition and could serve as a beneficial foundation for the genetic improvement of pork quality.

Whole transcriptome analysis in oviduct provides insight into microRNAs and ceRNA regulative networks that targeted reproduction of goat (Capra hircus)

BACKGROUND

Reproduction traits are crucial for livestock breeding and represent key economic indicators in the domestic goat (Capra hircus) industry. The oviduct, a critical organ in female mammals, plays a pivotal role in several reproductive processes; however, its molecular mechanisms remain largely unknown. Non-coding RNA and mRNAs are essential regulatory elements in reproductive processes; yet their specific roles and regulatory networks in goat oviducts remain unclear.

RESULTS

In this study, we conducted small RNA sequencing of the oviduct in high- and low-fecundity goats during the follicular (FH and FL groups, n = 10) and luteal (LH and LL groups, n = 10) phase, profiling 20 tissue samples. Combinatorial whole-transcriptome expression profiles were applied to the same samples to uncover the competitive endogenous RNA (ceRNA) regulation network associated with goat fecundity. RT-qPCR was employed to validate the miRNA profiling results, and ceRNA regulatory networks were analyzed through luciferase assay. Gene set enrichment analysis (GSEA) confirmed that the cytokine-cytokine receptor interaction and TGF-β signaling pathway, both related to embryonic development, were enriched in DEM target genes. Additionally, miR-328-3p, a core miRNA, targets SMAD3 and BOP1, which are involved in the negative regulation of cell growth and embryonic development. TOB1 and TOB2, targeted by miR-204-3p, regulate cell proliferation via the protein kinase C-activating G-protein coupled receptor signaling pathway. Analyses of ceRNA regulatory networks revealed that LNC_005981 - miR-328-3p - SMAD3 and circ_0021923 - miR-204-3p - DOT1L may affect goats' reproduction, findings that were validated using luciferase assay.

CONCLUSION

Analysis of whole-transcriptome profiling of goat oviducts identified several key miRNAs and ceRNAs that may regulate oocyte maturation, embryo development, and the interactions between the oviduct and gametes/early embryos, providing insights into the molecular mechanisms of reproductive regulatory networks.

Identification of Candidate Genes and Regulatory Competitive Endogenous RNA (ceRNA) Networks Underlying Intramuscular Fat Content in Yorkshire Pigs with Extreme Fat Deposition Phenotypes

Intramuscular fat (IMF) content is vital for pork quality, serving an important role in economic performance in pig industry. Non-coding RNAs, with mRNAs, are involved in IMF deposition; however, their functions and regulatory mechanisms in porcine IMF remain elusive. This study assessed the whole transcriptome expression profiles of the Longissimus dorsi muscle of pigs with high (H) and low (L) IMF content to identify genes implicated in porcine IMF adipogenesis and their regulatory functions. Hundreds of differentially expressed RNAs were found to be involved in fatty acid metabolic processes, lipid metabolism, and fat cell differentiation. Furthermore, combing co-differential expression analyses, we constructed competing endogenous RNAs (ceRNA) regulatory networks, showing crosstalk among 30 lncRNAs and 61 mRNAs through 20 miRNAs, five circRNAs and 11 mRNAs through four miRNAs, and potential IMF deposition-related ceRNA subnetworks. Functional lncRNAs and circRNAs (such as MSTRG.12440.1, ENSSSCT00000066779, novel_circ_011355, novel_circ_011355) were found to act as ceRNAs of important lipid metabolism-related mRNAs (LEP, IP6K1, FFAR4, CEBPA, etc.) by sponging functional miRNAs (such as ssc-miR-196a, ssc-miR-200b, ssc-miR10391, miR486-y). These findings provide potential regulators and molecular regulatory networks that can be utilized for research on IMF traits in pigs, which would aid in marker-assisted selection to improve pork quality.

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.

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.