Dynamic transcriptome changes during osteogenic differentiation of bone marrow-derived mesenchymal stem cells isolated from White Leghorns

Osteoblasts are indispensable for skeletal growth and maintenance. Bone marrow-derived mes-enchymal stem cells (BMSCs) are useful in studying osteogenesis. In this study, BMSCs, isolated from White Leghorns, were differentiated into osteoblasts in vitro. Cells induced for -1, 0, 1, 11, and 22 days were used for transcriptomic analyses using the HISAT2-Stringtie-DESeq2 pipeline. Weighted correlation network analysis was processed to investigate significant modules, in-cluding differentially expressed genes (DEGs), correlated with osteogenic differentiation. DEG gene ontology and pathway enrichment analyses were performed to elucidate the mechanisms of osteoblast differentiation. A total of 534, 1144, 1077, and 337 DEGs were identified between cells induced for -1 and 0, 0 and 1, 1 and 11, and 11 and 22 days, respectively (|log2FC| > 1.0, FDR < 0.05). DEGs were mainly enriched in pathways related to cell proliferation in the early stage of osteogenic differentiation, and pathways, such as the TGF-beta signaling pathway, in the middle and late stages of osteogenic differentiation. A protein-protein interaction network of the 87 DEGs in the MEturquoise module within top 5 %-degree value was set up utilizing the STRING database. This is the first study to elucidate the transcriptomic changes in the osteogenic differentiation of BMSCs isolated from White Leghorns at different times. Our results provide insight into the dynamic transcriptome changes during BMSC differentiation to osteoblasts.

成骨细胞（Osteoblasts）对于骨骼生长与维持不可或缺。骨髓来源间充质干细胞（Bone marrow-derived mesenchymal stem cells, BMSCs）是研究成骨过程的常用模型。本研究从白来航鸡（White Leghorns）中分离得到骨髓间充质干细胞，并在体外将其诱导分化为成骨细胞。分别选取诱导时长为-1、0、1、11和22天的细胞，采用HISAT2-Stringtie-DESeq2分析流程进行转录组学分析。通过加权基因共表达网络分析，探究与成骨分化相关的关键模块，其中包含差异表达基因（differentially expressed genes, DEGs）。对差异表达基因开展基因本体（Gene Ontology, GO）与通路富集分析，以阐明成骨细胞分化的分子机制。本研究共在诱导-1天与0天、0天与1天、1天与11天以及11天与22天的细胞组间，分别鉴定到534、1144、1077和337个差异表达基因（筛选阈值为|log₂FC|>1.0，错误发现率（False Discovery Rate, FDR）<0.05）。差异表达基因在成骨分化早期主要富集于细胞增殖相关通路，在中晚期则富集于转化生长因子-β（Transforming Growth Factor-beta, TGF-β）信号通路等通路。本研究基于STRING数据库，构建了MEturquoise模块中排名前5%度值的87个差异表达基因的蛋白质相互作用网络。本研究是首个阐明不同诱导时长下，白来航鸡来源骨髓间充质干细胞成骨分化过程中转录组变化的研究，其结果为揭示骨髓间充质干细胞向成骨细胞分化过程中的动态转录组变化提供了新的见解。