Sun Xiaoyu, Wu Tong, Chen Shuhong, Zhao Zheyu, Jia Ruiwei, Ma Jun, Yin Lei, Pan Xingbei, Ping Yifan, Mao Yixin, Ma Lulu, Ma Yilin, Luo Wu, Huang Shengbin, Liang Guang
Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China.
Department of Periodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China.
Theranostics. 2025 Jun 9;15(14):6719-6736. doi: 10.7150/thno.111360. eCollection 2025.
Bone homeostasis relies on a delicate equilibrium between bone formation by osteoblasts and bone resorption by osteoclasts. Disruption of this balance leads to various disorders, most notably osteoporosis. Deubiquitinating enzymes (DUBs), which cleave ubiquitin moieties from substrate proteins, play critical regulatory roles in bone pathophysiology. In this study, we explored the function of a DUB, ovarian tumor deubiquitinase 1 (OTUD1), in bone remodeling. We examined the femur bone of and male mice using micro-CT analyses and histomorphometry. The potential functions and mechanisms of OTUD1 were explored in bone marrow-derived macrophages, RAW264.7 cells, and bone marrow stromal cells using RT-qPCR, western blotting and immunofluorescence. Additionally, we employed liquid chromatography-tandem mass spectrometry (LC-MS/MS) coupled with co-immunoprecipitation (Co-IP) to identify OTUD1-interacting proteins and substrates. Our results demonstrated a significant downregulation of both the gene and protein level of OTUD1 during osteoclastogenesis. Furthermore, both whole-body knockout and myeloid-specific deficiency of OTUD1 resulted in reduced bone mass in male mice, driven by enhanced osteoclast differentiation. Mechanistically, OTUD1 maintained the stability of peroxiredoxin 1 (PRDX1) by reversing K48-linked ubiquitination, thereby mitigating mitochondrial dysfunction and suppressing osteoclast differentiation. Consistent with these results, mitochondria-targeted ubiquinone (MitoQ), a mitochondria-targeted antioxidant, effectively suppressed bone mass loss in OTUD1-deficient male mice. Our findings provided the first evidence that OTUD1 suppressed osteoclastogenesis by deubiquitinating PRDX1 and maintaining its stability, thereby offering a promising therapeutic approach for osteoclast-dependent bone diseases.
骨稳态依赖于成骨细胞形成骨与破骨细胞吸收骨之间的微妙平衡。这种平衡的破坏会导致各种疾病，最显著的是骨质疏松症。去泛素化酶（DUBs）可从底物蛋白上切割泛素部分，在骨病理生理学中发挥关键的调节作用。在本研究中，我们探讨了一种去泛素化酶——卵巢肿瘤去泛素化酶1（OTUD1）在骨重塑中的功能。我们使用显微CT分析和组织形态计量学检查了雄性小鼠的股骨。利用实时定量聚合酶链反应（RT-qPCR）、蛋白质印迹法和免疫荧光法，在骨髓来源的巨噬细胞、RAW264.7细胞和骨髓基质细胞中探索了OTUD1的潜在功能和机制。此外，我们采用液相色谱-串联质谱（LC-MS/MS）结合免疫共沉淀（Co-IP）来鉴定与OTUD1相互作用的蛋白质和底物。我们的结果表明，在破骨细胞形成过程中，OTUD1的基因和蛋白水平均显著下调。此外，OTUD1的全身敲除和髓系特异性缺陷均导致雄性小鼠骨量减少，这是由破骨细胞分化增强所致。从机制上讲，OTUD1通过逆转K48连接的泛素化来维持过氧化物还原酶1（PRDX1）的稳定性，从而减轻线粒体功能障碍并抑制破骨细胞分化。与这些结果一致，线粒体靶向抗氧化剂线粒体靶向泛醌（MitoQ）有效抑制了OTUD1缺陷雄性小鼠的骨量流失。我们的研究结果首次证明，OTUD1通过去泛素化PRDX1并维持其稳定性来抑制破骨细胞形成，从而为破骨细胞依赖性骨疾病提供了一种有前景的治疗方法。
