Department of Orthopedics, First Hospital of China Medical University, Shenyang, Liaoning, 110000, China.
Department of Internal Medicine, Shanghai Pudong New Area People's Hospital, Shanghai, 200000, China.
J Bone Miner Res. 2024 Aug 5;39(7):980-993. doi: 10.1093/jbmr/zjae065.
The role of monocytes in postmenopausal osteoporosis is widely recognized; however, the mechanisms underlying monocyte reprogramming remain unknown. In this study, single-cell RNA sequencing (scRNA-seq) was conducted on CD14+ bone marrow monocytes obtained from 3 postmenopausal women with normal BMD and 3 women with postmenopausal osteoporosis (PMOP). Monocle2 was used to classify the monocytes into 7 distinct clusters. The proportion of cluster 1 significantly decreased in PMOP patients, while the proportion of cluster 7 increased. Further analysis via GSEA, transcription factor activity analysis, and sc-metabolic analysis revealed significant differences between clusters 1 and 7. Cluster 7 exhibited upregulated pathways associated with inflammation, immunity, and osteoclast differentiation, whereas cluster 1 demonstrated the opposite results. Monocle2, TSCAN, VECTOR, and scVelo data indicated that cluster 1 represented the initial subset and that cluster 7 represents one of the terminal subsets. BayesPrism and ssGSEA were employed to analyze the bulk transcriptome data obtained from the GEO database. The observed alterations in the proportions of 1 and 7 were validated and found to have diagnostic significance. CD16 serves as the marker gene for cluster 7, thus leading to an increased proportion of CD16+ monocytes in women with PMOP. Flow cytometry was used to assess the consistency of outcomes with those of the bioinformatic analysis. Subsequently, an additional scRNA-seq analysis was conducted on bone marrow mononuclear cells obtained from 3 patients with PMOP and 3 postmenopausal women with normal BMD. The differential proportions of cluster 1 and cluster 7 were once again confirmed, with the pathological effect of cluster 7 may attribute to cell-cell communication. The scRNA-seq findings suggest that an imbalance in monocyte subsets is a characteristic feature of PMOP. These findings elucidate the limitations of utilizing bulk transcriptome data for detecting alterations in monocytes, which may influence novel research inquiries.
单核细胞在绝经后骨质疏松症中的作用已被广泛认识；然而，单核细胞重编程的机制尚不清楚。在这项研究中，对 3 名绝经后骨密度正常的女性和 3 名绝经后骨质疏松症（PMOP）患者的骨髓 CD14+单核细胞进行了单细胞 RNA 测序（scRNA-seq）。使用 Monocle2 将单核细胞分为 7 个不同的簇。PMOP 患者簇 1 的比例显著降低，而簇 7 的比例增加。通过 GSEA、转录因子活性分析和 sc 代谢分析进一步分析，发现簇 1 和簇 7 之间存在显著差异。簇 7 表现出与炎症、免疫和破骨细胞分化相关的上调途径，而簇 1 则表现出相反的结果。Monocle2、TSCAN、VECTOR 和 scVelo 数据表明，簇 1 代表初始亚群，而簇 7 代表终末亚群之一。BayesPrism 和 ssGSEA 用于分析从 GEO 数据库获得的批量转录组数据。观察到 1 和 7 的比例发生变化，并发现具有诊断意义。CD16 是簇 7 的标记基因，因此导致 PMOP 女性中 CD16+单核细胞比例增加。流式细胞术用于评估生物信息学分析结果的一致性。随后，对 3 名 PMOP 患者和 3 名绝经后骨密度正常的女性的骨髓单核细胞进行了额外的 scRNA-seq 分析。再次证实了簇 1 和簇 7 的差异比例，簇 7 的病理作用可能归因于细胞间通讯。scRNA-seq 结果表明，单核细胞亚群的失衡是 PMOP 的特征。这些发现阐明了利用批量转录组数据检测单核细胞变化的局限性，这可能会影响新的研究探索。
