In this study, Squalene epoxidase (SQLE) overexpression vector was transfected into bovine skeletal muscle-derived mesenchymal stem/stromal cells (MSCs) to study the molecular mechanism of SQLE regulating meat quality through myogenesis. We initially profiled the expression of SQLE in cattle embryos and adults, in the muscle tissue of four different cattle varieties, and in 11 different tissues/organs of Guangxi cattle variety. Subsequently, we isolated and cultured bovine skeletal muscle-derived MSCs and detected the expression of SQLE during cell proliferation and differentiation. Then, we constructed a bovine SQLE overexpression vector and transfected it into bovine skeletal muscle-derived MSCs by liposome transfection. Cell Counting Kit-8 (CCK-8), 5-ethynyl-20-deoxyuridine (EdU), flow cytometry, immunofluorescence, and quantitative polymerase chain reaction assays were used to characterize cell proliferation and differentiation in detail. The results showed that the relative expression level of bovine SQLE gene in brain tissue was the highest, and in adult muscle tissue was significantly higher than that in embryonic stage. Especially, the expression of SQLE was significantly upregulated in cell differentiation stage. Furthermore, the proliferation, cell cycle, apoptosis, and myoblast differentiation assays indicated that SQLE significantly promoted the differentiation and apoptosis of bovine skeletal muscle-derived MSCs, but inhibited their proliferation. In conclusion, our study reveals the role of SQLE in myoblast differentiation. These results will provide new clues for the regulation network of bovine muscle development.

中文翻译：

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SQLE促进牛骨骼肌源间充质干细胞的分化和凋亡。

在这项研究中，角鲨烯环氧酶（SQLE）过表达载体被转染到牛骨骼肌间充质干/基质细胞（MSCs）中，以研究SQLE通过成肌作用调节肉质的分子机制。我们最初分析了SQLE在牛胚胎和成年牛，四种不同牛品种的肌肉组织以及广西牛品种的11种不同组织/器官中的表达。随后，我们分离并培养了牛骨骼肌来源的MSC，并检测了细胞增殖和分化过程中SQLE的表达。然后，我们构建了牛SQLE过表达载体，并通过脂质体转染将其转染到牛骨骼肌来源的MSC中。Cell Counting Kit-8（CCK-8），5-乙炔基-20-脱氧尿苷（EdU），流式细胞仪，免疫荧光，定量聚合酶链反应分析用于表征细胞增殖和分化。结果表明，牛SQLE基因在脑组织中的相对表达水平最高，在成年肌肉组织中的相对表达水平显着高于胚胎期。特别是在细胞分化阶段，SQLE的表达明显上调。此外，增殖，细胞周期，凋亡和成肌细胞分化试验表明SQLE显着促进牛骨骼肌来源的MSC的分化和凋亡，但抑制了它们的增殖。总之，我们的研究揭示了SQLE在成肌细胞分化中的作用。这些结果将为牛肌肉发育的调控网络提供新的线索。