Wang Yanna, Wang Changyuan, Gong Ying, Li Qingchen, Liu Mozhen, Sun Huijun
Department of Clinical Pharmacology, College of Pharmacy, Dalian Medical University, 9 West Section, Lvshun South Road, Dalian, Lvshunkou District 116044, China.
Department of Orthopaedics, the First Affiliated Hospital, Dalian Medical University, No. 222, Zhongshan Road, Dalian, Xigang District 116011, China.
Tissue Cell. 2025 Jun;94:102790. doi: 10.1016/j.tice.2025.102790. Epub 2025 Feb 11.
Osteoporosis (OP) is a common disease of aging, which is closely related to the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). DNA damage, as a senescence-associated secretory phenotype (SASP), plays an important role in aging diseases including OP. GIT2 has been identified as a DNA repair gene and alleviates aging-related phenotypes. However, the relationship between GIT2 and osteogenic differentiation of BMSCs remains unclear.
Here, we used bioinformatics analysis to identify the gene GIT2, which is closely related to aging, OP and DNA damage, and its downstream targets. Then, HO -induced BMSCs senescence model and ovariectomy-induced mice OP model was established in vitro and in vivo, respectively. Micro-CT, H&E staining, toluidine blue staining, and calcein double labeling were used to analyze bone mass, osteogenic differentiation phenotype, and bone formation rate. Comet assay, Elisa and immunofluorescence were used to analyze senescence-related phenotypes. Western blotting was used to detect the protein levels of GIT2/TRAF3/NF-κB axis and osteogenesis-related markers.
Our results showed that GTI2 and TRAF3 were positively correlated with OP-related markers. On the one hand, GIT2 could inhibit the activation of both canonical and non-canonical NF-κB signaling pathways by positively regulating TRAF3. On the other hand, GIT2 could directly bind to P65, a component of the classical NF-κB signaling pathway, and P52, a component of the non-classical NF-κB signaling pathway, to inhibit their activation, improve DNA damage repair, alleviate cell senescence, and further promote osteogenic differentiation of BMSCs.
In summary, the present study demonstrates that GIT2 plays a crucial regulatory role in promoting osteogenic differentiation of BMSCs, which provides new ideas for the prevention and treatment of OP and other aging-related diseases.
骨质疏松症（OP）是一种常见的衰老相关疾病，与骨髓间充质干细胞（BMSCs）的成骨分化密切相关。DNA损伤作为一种衰老相关分泌表型（SASP），在包括OP在内的衰老疾病中起重要作用。GIT2已被鉴定为一种DNA修复基因，并可减轻衰老相关表型。然而，GIT2与BMSCs成骨分化之间的关系仍不清楚。
在此，我们利用生物信息学分析来鉴定与衰老、OP和DNA损伤密切相关的基因GIT2及其下游靶点。然后，分别在体外和体内建立了过氧化氢（HO）诱导的BMSCs衰老模型和卵巢切除诱导的小鼠OP模型。采用显微CT、苏木精-伊红（H&E）染色、甲苯胺蓝染色和钙黄绿素双标记法分析骨量、成骨分化表型和骨形成率。采用彗星试验、酶联免疫吸附测定（ELISA）和免疫荧光法分析衰老相关表型。采用蛋白质印迹法检测GIT2/TRAF3/NF-κB轴和骨生成相关标志物的蛋白水平。
我们的结果表明，GTI2和TRAF3与OP相关标志物呈正相关。一方面，GIT2可通过正向调节TRAF3抑制经典和非经典NF-κB信号通路的激活。另一方面，GIT2可直接与经典NF-κB信号通路的组分P65和非经典NF-κB信号通路的组分P52结合，抑制它们的激活，改善DNA损伤修复，减轻细胞衰老，并进一步促进BMSCs的成骨分化。
综上所述，本研究表明GIT2在促进BMSCs成骨分化中起关键调节作用，为OP和其他衰老相关疾病的预防和治疗提供了新思路。
