Enhanced osteoclastogenesis and osteoclast activity contribute to the development of osteoporosis, which is characterized by increased bone resorption and inadequate bone formation. As novel antiosteoporotic therapeutics are needed, understanding the genetic regulation of human osteoclastogenesis could help identify potential treatment targets. This study aimed to provide an overview of transcriptional reprogramming during human osteoclast differentiation. Osteoclasts were differentiated from CD14⁺ monocytes from eight female donors. RNA sequencing during differentiation revealed 8 980 differentially expressed genes grouped into eight temporal patterns conserved across donors. These patterns revealed distinct molecular functions associated with postmenopausal osteoporosis susceptibility genes based on RNA from iliac crest biopsies and bone mineral density SNPs. Network analyses revealed mutual dependencies between temporal expression patterns and provided insight into subtype-specific transcriptional networks. The donor-specific expression patterns revealed genes at the monocyte stage, such as filamin B (FLNB) and oxidized low-density lipoprotein receptor 1 (OLR1, encoding LOX-1), that are predictive of the resorptive activity of mature osteoclasts. The expression of differentially expressed G-protein coupled receptors was strong during osteoclast differentiation, and these receptors are associated with bone mineral density SNPs, suggesting that they play a pivotal role in osteoclast differentiation and activity. The regulatory effects of three differentially expressed G-protein coupled receptors were exemplified by in vitro pharmacological modulation of complement 5 A receptor 1 (C5AR1), somatostatin receptor 2 (SSTR2), and free fatty acid receptor 4 (FFAR4/GPR120). Activating C5AR1 enhanced osteoclast formation, while activating SSTR2 decreased the resorptive activity of mature osteoclasts, and activating FFAR4 decreased both the number and resorptive activity of mature osteoclasts. In conclusion, we report the occurrence of transcriptional reprogramming during human osteoclast differentiation and identified SSTR2 and FFAR4 as antiresorptive G-protein coupled receptors and FLNB and LOX-1 as potential molecular markers of osteoclast activity. These data can help future investigations identify molecular regulators of osteoclast differentiation and activity and provide the basis for novel antiosteoporotic targets.

破骨细胞生成和破骨细胞活性增强导致骨质疏松症的发展，其特征是骨吸收增加和骨形成不足。由于需要新的抗骨质疏松疗法，了解人类破骨细胞生成的遗传调控可能有助于确定潜在的治疗靶点。本研究旨在概述人类破骨细胞分化过程中的转录重编程。破骨细胞与 8 名女性供体的 CD14 ⁺ 单核细胞分化而来。分化过程中的 RNA 测序显示，8 980 个差异表达基因分为 8 个时间模式，在供体中是保守的。这些模式揭示了与绝经后骨质疏松症易感基因相关的不同分子功能，这些基因基于髂嵴活检的 RNA 和骨矿物质密度 SNP。网络分析揭示了时间表达模式之间的相互依赖关系，并提供了对亚型特异性转录网络的见解。供体特异性表达模式揭示了单核细胞阶段的基因，如细丝蛋白 B （FLNB） 和氧化低密度脂蛋白受体 1 （OLR1，编码 LOX-1），这些基因可预测成熟破骨细胞的吸收活性。在破骨细胞分化过程中，差异表达的 G 蛋白偶联受体的表达很强，这些受体与骨矿物质密度 SNP 相关，表明它们在破骨细胞分化和活性中起关键作用。 三种差异表达的 G 蛋白偶联受体的调节作用通过补体 5 A 受体 1 （C5AR1） 、生长抑素受体 2 （SSTR2） 和游离脂肪酸受体 4 （FFAR4/GPR120） 的体外药理学调节来例证。激活 C5AR1 增强了破骨细胞的形成，而激活 SSTR2 降低了成熟破骨细胞的再吸收活性，激活 FFAR4 降低了成熟破骨细胞的数量和再吸收活性。总之，我们报道了人破骨细胞分化过程中转录重编程的发生，并确定 SSTR2 和 FFAR4 为抗吸收 G 蛋白偶联受体，FLNB 和 LOX-1 为破骨细胞活性的潜在分子标志物。这些数据可以帮助未来的研究确定破骨细胞分化和活性的分子调节因子，并为新的抗骨质疏松靶点提供基础。