Project description:Abstract Background: Intramuscular fat refers to the white adipose tissue deposited between muscle fibers, and its quantity and distribution directly impact the quality and value of beef. Compared to subcutaneous fat, intramuscular fat develops later and accumulates more slowly in cattle. The reasons for the delayed development and slower growth of intramuscular fat in cattle remain unclear. Results: Histological analysis showed that adipocytes in intramuscular fat were smaller than those in subcutaneous fat from the same mature cattle, indicating a delayed development or slower growth of intramuscular fat compared to subcutaneous fat. Intramuscular fat had a lower capacity for retaining or incorporating long-chain fatty acids into triglycerides than subcutaneous fat. Comparing the transcriptomes of intramuscular and subcutaneous fat by RNA sequencing identified more than 1,000 genes differentially expressed (DEGs) between the two adipose depots. Genes upregulated in intramuscular fat included FOXO6, SLC27A1, HDAC9, WWTR1, and PIK3C2A, which are known to inhibit adipose tissue development and growth. Genes downregulated in intramuscular fat included FABP4, AGPAT2, ADIG, ADIRF, and PLIN2, which are known to promote adipose tissue development and growth. Functional enrichment analyses of these DEGs suggested that intramuscular fat may have a lower capacity for fatty acid binding and adipogenesis compared to subcutaneous fat. Furthermore, genes downregulated in intramuscular fat were enriched in signaling pathways such as the PPAR signaling pathway, whereas genes upregulated in intramuscular fat were enriched in pathways including the Wnt signaling pathway. Stromal vascular fraction (SVF) cells from intramuscular fat exhibited a lower adipogenic potential than those from subcutaneous fat. Conclusion: Multiple factors may contribute to the delayed and slower deposition of intramuscular fat compared to subcutaneous fat in cattle, including reduced fatty acid binding capacity, lower triglyceride synthesis, and decreased adipogenesis in intramuscular fat. These differences are possibly driven by lower expressions of genes such as AGPAT2, FABP4, and ADIG, higher expression of genes such as FOXO6, HDAC9, and SLC27A1, reduced activation of the PPAR signaling pathway, and increased activation of the Wnt signaling pathway in intramuscular fat.

Project description:*Background: Adipocytes mainly function as energy storage and endocrine cells. The amount and distribution of fat are important factor that influence the meat quality in the beef industry. Fat depot can be found around internal organ (ometal), beneath the skin (subcutaneous), and between muscles (intramuscular). Different adipose depot showed the biological and genetic difference depending on their location. This inter-depot variation might be influenced by the inherent genetic programing for development of adipose depots. In this study, we used RNA-seq data to investigate the difference in transcriptome of various adipose depots in Hanwoo. *Results: Using RNA-seq, we identified 5797, 2156, and 5455 DEGs in the comparison between OI, OS, and IS respectively (FDR<0.01) and found 853, 48, and 979 DEGs specific to subcutaneous, intramuscular and omental fat respectively. DEGs in intramuscular fat were highly enriched the metabolism related pathways compared to other fat depots. DEGs specific to the omental fat is significantly enriched in PPAR signaling pathway and cell-junction related pathway. In subcutaneous fat, cytokine-cytokine receptor interaction with chemokines (CXC and CC subfamily) was the most significantly enriched the pathways. Interestingly, melanogenesis pathway was associated with the subcutaneous depot. Even though the adipose tissues shared the same pathways for adipocyte differentiation, the regulation of genes were different based on the depot. *Conclusions: We comparatively analyzed the transcripome profile from different adipose tissues using NGS and identified DEGs between adipose depot and specific to depot in Hanwoo animals. The functional annotation analysis of DEGs found that transcriptome profile difference in various adipose tissue of intramuscular, subcutaneous, and ometal fat. whole mRNA sequencing profiles of nine Korean native cattle (nine profiles of omental fat tissue, nine profiles of intramuscular fat tissue, nine profiles of subcutaneous fat tissue and eight profiles of muscle tissue)

Project description:MicroRNAs (miRNAs) are small non-coding RNAs found to regulate several biological processes including adipogenesis. Understanding adipose tissue regulation is critical for beef cattle as fat is an important determinant of beef quality and nutrient value . This study analyzed the association between genomic context characteristics of miRNAs with their expression and function in bovine adipose tissue. Twenty-four subcutaneous adipose tissue biopsies were obtained from eight British-continental crossbred steers at 3 different time points . Total RNA was extracted and miRNAs were profiled using a miRNA microarray with expression further validated by qRT-PCR. A total of 224 miRNAs were detected of which 155 were expressed in all steers (n=8), and defined as the core miRNAs of bovine subcutaneous adipose tissue. Core adipose miRNAs varied in terms of genomic location (59.5% intergenic, 38.7% intronic, 1.2% exonic, and 0.6% mirtron), organization (55.5% non-clustered and 44.5% clustered), and conservation (49% highly conserved, 14% conserved and 37% poorly conserved). Clustered miRNAs and highly conserved miRNAs were more highly expressed (p<0.05) and had more predicted targets than non-clustered or less conserved miRNAs (p<0.001). A total of 34 miRNAs were coordinately expressed, being part of six identified relevant networks. Two intronic miRNAs (miR-33a and miR-1281) were shown to have coordinated expression with their host genes which are involved in lipid metabolism, suggesting these miRNAs may also play a role in regulation of lipid metabolism/adipogenesis of bovine adipose tissue. Furthermore, a total of 17 bovine specific miRNAs were predicted to be involved in the regulation of energy balance in adipose tissue. These findings improve our understanding on the behavior of miRNAs in the regulation of bovine adipogenesis and fat metabolism as it reveals that miRNA expression patterns and functions are associated with miRNA genomic organization and conservation in bovine adipose tissue. In this study, a total of 24 subcutaneous adipose tissue samples were analyzed by microRNA microarrays. The samples were derived from eight steers at three different ages (12, 13.5 and 15 months).

Project description:MicroRNAs (miRNAs) are small non-coding RNAs found to regulate several biological processes including adipogenesis. Understanding adipose tissue regulation is critical for beef cattle as fat is an important determinant of beef quality and nutrient value . This study analyzed the association between genomic context characteristics of miRNAs with their expression and function in bovine adipose tissue. Twenty-four subcutaneous adipose tissue biopsies were obtained from eight British-continental crossbred steers at 3 different time points . Total RNA was extracted and miRNAs were profiled using a miRNA microarray with expression further validated by qRT-PCR. A total of 224 miRNAs were detected of which 155 were expressed in all steers (n=8), and defined as the core miRNAs of bovine subcutaneous adipose tissue. Core adipose miRNAs varied in terms of genomic location (59.5% intergenic, 38.7% intronic, 1.2% exonic, and 0.6% mirtron), organization (55.5% non-clustered and 44.5% clustered), and conservation (49% highly conserved, 14% conserved and 37% poorly conserved). Clustered miRNAs and highly conserved miRNAs were more highly expressed (p<0.05) and had more predicted targets than non-clustered or less conserved miRNAs (p<0.001). A total of 34 miRNAs were coordinately expressed, being part of six identified relevant networks. Two intronic miRNAs (miR-33a and miR-1281) were shown to have coordinated expression with their host genes which are involved in lipid metabolism, suggesting these miRNAs may also play a role in regulation of lipid metabolism/adipogenesis of bovine adipose tissue. Furthermore, a total of 17 bovine specific miRNAs were predicted to be involved in the regulation of energy balance in adipose tissue. These findings improve our understanding on the behavior of miRNAs in the regulation of bovine adipogenesis and fat metabolism as it reveals that miRNA expression patterns and functions are associated with miRNA genomic organization and conservation in bovine adipose tissue.

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