ITGB3, an osteoclast marker, is involved in osteoclast formation. Nevertheless, its related mechanism remains poorly characterized. Herein, this study examines the mechanisms affecting osteoclast formation with the involvement of ITGB3. Osteoclast formation was induced with macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor-kappa B ligand (RANKL), followed by measurement of the mRNA and protein expression of ITGB3 and LSD1. After gain- and loss-of-function assays, cell viability and the expression of osteoclast marker genes (NFATc1, ACP5, and CTSK) were assessed, and osteoclast formation was evaluated with TRAP staining. ChIP assays were used to examine histone 3 lysine 9 (H3K9) monomethylation (H3K9me1) and H3K9 dimethylation (H3K9me2) modifications and LSD1 protein enrichment in the ITGB3 promoter. During osteoclast formation, ITGB3 and LSD1 were gradually augmented. Knockdown of LSD1 or ITGB3 curbed cell viability, the expression of osteoclast marker genes, and osteoclast formation. Moreover, overexpression of ITGB3 nullified the suppressive impact of LSD1 knockdown on osteoclast formation. Mechanistically, LSD1 promoted ITGB3 expression by reducing H3K9 levels in the ITGB3 promoter. LSD1 enhanced ITGB3 expression by decreasing H3K9me1 and H3K9me2 levels in ITGB3 promoter to boost osteoclast formation.

ITGB3 是一种破骨细胞标记物，参与破骨细胞形成。然而，其相关机制仍知之甚少。在此，本研究探讨了 ITGB3 参与影响破骨细胞形成的机制。用巨噬细胞集落刺激因子（M-CSF）和核因子κB配体受体激活剂（RANKL）诱导破骨细胞形成，然后测量ITGB3和LSD1的mRNA和蛋白表达。功能获得和丧失检测后，评估细胞活力和破骨细胞标记基因（NFATc1、ACP5 和 CTSK）的表达，并用TRAP 染色评估破骨细胞形成。ChIP 检测用于检查 ITGB3 启动子中的组蛋白 3 赖氨酸 9 (H3K9) 单甲基化 (H3K9me1) 和 H3K9 二甲基化 (H3K9me2) 修饰以及 LSD1 蛋白富集。在破骨细胞形成过程中，ITGB3和LSD1逐渐增强。LSD1 或 ITGB3 的敲低抑制了细胞活力、破骨细胞标记基因的表达和破骨细胞的形成。此外，ITGB3的过度表达消除了LSD1敲低对破骨细胞形成的抑制作用。从机制上讲，LSD1 通过降低 ITGB3 启动子中的 H3K9 水平来促进 ITGB3 表达。LSD1 通过降低 ITGB3 启动子中的 H3K9me1 和 H3K9me2 水平来增强 ITGB3 表达，从而促进破骨细胞形成。