The transcription factor, early growth response 1 (EGR1), has important roles in various cell types in response to different stimuli. EGR1 is thought to be involved in differentiation of bovine skeletal muscle-derived satellite cells (MDSCs); however, the precise effects of EGR1 on differentiation of MDSCs and its mechanism of action remain unknown. In the present study, a

To study milk synthesis in dairy goat mammary gland, we had established an in vitro lactating dairy goat mammary epithelial cell (DGMEC) line. Mammary tissues of Guan Zhong dairy goats at 35 d of lactation were dispersed and cultured in a medium containing epithelial growth factor, insulin-like growth factor-1, insulin transferrin serum, and fetal bovine serum. Epithelial cells were enriched by digesting with 0.25% trypsin repeatedly to remove fibroblast cells and were identified as epithelial origin by staining with antibody against cytokeratine 18. The DGMECs displayed monolayer, cobble-stone, epithelial-like morphology, and formed alveoli-like structures and island monolayer aggregates which were the typical characteristics of mammary epithelial cells. A one-half logarithmically growth curve and cytoplasmic lipid droplets in these cells were observed. In this paper, we also studied the lactating function of DGMECs. Results showed that DGMECs could secrete lactose and β-casein. Lactating function of the cells had no obvious change after 48 h treated by insulin, while prolactin could obviously raise the secretion of milk proteins and lactose.

Fatty acids (FAs) play essential roles in regulating differentiation and proliferation by affecting gene expression in various cell types. However, their potential functions in bovine cells remain unclear. Herein, we examine the differentiation and proliferation of bovine skeletal muscle-derived satellite cells (MDSCs) after incubation with three types of representative FAs (palmitic acid, oleic acid and docosahexaenoic acid) by western blotting, immunofluorescence assays, flow cytometry analysis and EdU incorporation assays. The myotube fusion rate, myotube length and expression levels of muscle differentiation-related gene myogenin (MYOG) and myosin heavy chain 3 (MYH3) increased significantly, although the FAs did not affect proliferation. Additionally, FA-induced bovine MDSC differentiation increased ELOVL3 expression and relocation of ELOVL3 to cytoplasmic lipid droplets in the differentiation of bovine MDSCs. Moreover, the effect of FAs on bovine MDSC differentiation was inhibited upon ELOVL3 downregulation. Collectively, these data indicate that FAs promote bovine MDSC differentiation by regulating ELOVL3 expression.

Podocan, a small leucine‐rich repeat protein, is a negative regulator of cell proliferation. In this study, we demonstrated that podocan is involved in the differentiation of C2C12 murine myoblasts. Podocan expression increased with the progression of C2C12 differentiation. As expect, siRNA‐mediated podocan knockdown inhibited C2C12 differentiation, as indicated by inhibition of MYOG, MYH2, and desmin expression, as well as reductions in the differentiation and fusion indices. Overexpression of podocan using dCas9 technology promoted C2C12 cell differentiation. In addition, supplementation of culture medium with podocan influenced C2C12 differentiation. Podocan knockdown reduced Wnt/β‐catenin signaling, characterized by a reduction in the nuclear translocation of β‐catenin, whereas podocan overexpression had the opposite effect. Furthermore, treatment with XAV939, an inhibitor of Wnt/β‐catenin, reduced the podocan‐mediated promotion of C2C12 differentiation. Induction of muscle injury in mice by bupivacaine administration suggested that podocan may play a role in muscle regeneration. In summary, our results suggest that podocan is required for normal C2C12 differentiation and that its role in myogenesis is mediated by the Wnt/β‐catenin pathway.

Extracellular matrix components have important regulatory functions during cell proliferation and differentiation. In recent study, extracellular matrix were shown to have a strong effect on skeletal muscle differentiation. Here, we aimed to elucidate the effects of extracellular matrix protein 2 (ECM2), an extracellular matrix component, on the differentiation of bovine skeletal muscle-derived satellite cells (MDSCs). Western blot and immunofluorescence analyses were used to elucidate the ECM2 expression pattern in bovine MDSCs during differentiation in vitro. CRISPR/Cas9 technology was used to activate or inhibit ECM2 expression to study its effects on the in vitro differentiation of bovine MDSCs. ECM2 expression was shown to increase gradually during bovine MDSC differentiation, and the levels of this protein were higher in more highly differentiated myotubes. ECM2 activation promoted MDSC differentiation, whereas its suppression inhibited the differentiation of these cells. Here, for the first time, we demonstrated the importance of ECM2 expression during bovine MDSC differentiation; these results could lead to treatments that help to increase beef cattle muscularity.