Effects and mechanisms of high-dose glucocorticoids on senescence, apoptosis, and osteogenic differentiation of bone marrow mesenchymal stem cells
10.3760/cma.j.cn121113-20250316-00264
- VernacularTitle:高剂量糖皮质激素对骨髓间充质干细胞衰老、凋亡和成骨分化的影响及机制
- Author:
Zhendong YING
1
;
Changjun CHEN
;
Dailing CHEN
;
Qiuru WANG
;
Qibin LIU
;
Qingwei MA
;
Lei ZHANG
;
Pengde KANG
;
Xin ZHAO
Author Information
1. 山东中医药大学第二临床医学院（山东省千佛山医院）骨外科，济南 250012
- Publication Type:Journal Article
- Keywords:
Mesenchymal stem cells;
Glucocorticoids;
Aging;
Apoptosis;
Osteogenic differentiation;
Glucocorticoid-induced osteonecrosis of the femoral head
- From:
Chinese Journal of Orthopaedics
2025;45(18):1208-1216
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To elucidate the molecular mechanisms through which high-dose dexamethasone exerts long-term effects on bone marrow mesenchymal stem cells (BMSCs), specifically its role in suppressing osteogenic differentiation, accelerating cellular senescence, triggering the senescence-associated secretory phenotype (SASP), and inducing apoptosis.Methods:Primary rat BMSCs were isolated and treated with high-dose dexamethasone (1×10 -4 mol/L) to establish the experimental group, while untreated cells served as the control. The gene and protein expression levels of osteogenic markers, bone alkaline phosphatase (bALP) and Runt-related transcription factor 2 (Runx2), were analyzed in both groups. Cellular senescence was evaluated using senescence-associated β-galactosidase (SA-β-gal) staining. The expression of senescence-related markers (P16 and P21), components of the senescence-associated secretory phenotype (SASP), including tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and interferon (IFN)-γ, as well as apoptosis-related proteins (Bcl-2, Bax, and Cleaved-Caspase-3), and key factors of the Nrf2/HO-1 signaling pathway were assessed at both transcriptional and protein levels using qRT-PCR, immunofluorescence, and Western-blot analyses. These comprehensive evaluations aimed to determine the senescent state, apoptotic features, and alterations in osteogenic differentiation of BMSCs. Results:Following treatment with dexamethasone and subsequent withdrawal, both qRT-PCR and Western blot analyses indicated a significant reduction in the expression of the osteogenic markers bALP and Runx2 at both mRNA and protein levels. The proportion of SA-β-gal positive cells was markedly higher in the dexamethasone group (74.33%±6.89%) than in the control group (20.30%±1.57%, t=17.300, P<0.001). qRT-PCR analysis revealed upregulated mRNA expression of the senescence-related genes P16 and P21 after dexamethasone treatment, which was further supported at the protein level by immunofluorescence showing increased P21 expression. Western-blot results confirmed that protein expression levels of P16 and P21 were significantly elevated in the dexamethasone group (7.025±0.255 and 6.362±0.456, respectively) compared with the control group (1.016±0.115 and 0.816±0.172; both P<0.05). Furthermore, gene expression levels of the senescence-associated secretory phenotype (SASP) factors TNF-α and IL-1β were significantly increased (TNF-α: 3.539±0.599 vs. 0.742±0.095; IL-1β: 4.469±0.331 vs. 0.799±0.175; both P<0.05), and their protein expression was consistently upregulated as validated by Western-blot. Additionally, protein expression levels of TNF-α, IL-1β, and IFN-γ were significantly higher in the dexamethasone-treated group (3.476±0.932 vs. 0.945±0.095; 4.111±0.220 vs. 0.762±0.105; 2.155±0.240 vs. 0.656±0.104; all P<0.05).Western-blot analysis also demonstrated that protein expression of Nrf2 and HO-1 was significantly suppressed in the dexamethasone group (0.21±0.07 and 0.19±0.06, respectively) compared with the control group (1.13±0.15 and 0.92±0.21; P<0.05). Moreover, Western-blot analysis revealed that the expression levels of the pro-apoptotic proteins Bax and Cleaved-Caspase-3 were significantly up, regulated in the dexamethasone, treated BMSCs (Bax: 3.673±0.397 vs. 0.453±0.111; Cleaved-Caspase-3: 3.863±0.399 vs. 0.465±0.057), while the expression of the anti-apoptotic protein Bcl-2 was markedly down, regulated (0.959±0.073 vs. 2.126±0.195), with all differences being statistically significant ( P<0.05). Conclusions:High-dose dexamethasone treatment of BMSCs, followed by withdrawal of dexamethasone, induces cellular senescence and enhances the expression of the senescence-associated secretory phenotype (SASP) through suppression of the Nrf2/HO-1 signaling pathway. Concurrently, it promotes apoptosis by activating the mitochondrial apoptotic pathway, collectively leading to impaired osteogenic differentiation of BMSCs.
