Subcutaneous fat thickness and intramuscular fat content are closely related to meat production and quality in the pig industry. Adipogenesis in adipocytes from subcutaneous and intramuscular fat tissues involves different genes and regulatory mechanisms. Analyzing the data of mRNA and miRNA transcriptomes during the differentiation of adipocytes from these two sources will help identify the different mechanisms of subcutaneous and intramuscular fat deposition. In this study, RNA sequencing technology was used to analyze the differential expression of genes and miRNAs in subcutaneous and intramuscular adipocytes at days 0, 2, 4, and 8 of differentiation. We mainly attributed the difference between fat depositions of the two types of adipocytes to variations in the expression patterns of related genes. Through combined weighted gene co-expression network analysis and K-MEANS, we identified 30 and 22 genes that mainly regulated the differentiation of subcutaneous adipocytes and intramuscular adipocytes, respectively. A total of 17 important candidate miRNAs were identified. This study provides valuable reference for the study of different mechanisms of adipogenesis among subcutaneous and intramuscular fat and contributes to improving pig breeding.

Somatic cell preservation is an effective strategy for conserving the genetic potential of endangered species. To contribute to the conservation of the Milu deer (Elaphurus davidianus), this study aimed to establish and characterize an immortalized skin fibroblast cell line (ML-iSFC). The cell line is based on fibroblasts from the skin tissue of a male fawn of Milu deer. Optimal culture conditions were determined by supplementing the culture medium with different growth factors, and immortalization was achieved through simian virus 40 large T antigen (SV40T) transduction. Optimal culturing conditions for the cells were determined by adding a range of growth factors. The cellular morphology, growth characteristics, and marker expression of the cells were further evaluated. Cell cycle and proliferation were assessed by flow cytometry and CCK-8 assays, respectively. Chromosomes were determined by karyotype analysis. The highest cell growth rate was observed when the culture medium was supplemented with 3 ng/mL of FGF2. The fibroblast-specific marker vimentin (VIM) was expressed in both ML-SFC and ML-iSFC, while the epithelial marker keratin 18 (KRT18) was weakly expressed in ML-SFC cells. Cell proliferation and cell-cycle analysis revealed that ML-iSFC exhibited a higher growth rate and greater vitality compared to ML-SFC. Karyotype analysis showed that ML-iSFC maintained the same chromosome number and morphology as ML-SFC. In summary, this study reports the successful construction of an immortalized fibroblast cell line from Milu deer, which will serve as a valuable tool for Milu deer conservation.