Jiang Yue, Ye Ai-Hua, He Wen-Ge, Liu Lu, Gao Xiang, Liu Hang, Liu Wen-Ting, Ye Fang-Lin, He Dong-Mei, Liao Jun-Yi, Wang Jing, He Bai-Cheng
Department of Pharmacology, School of Pharmacy, Chongqing Medical University, No. 1 Yixueyuan Road, Yuzhong District, Chongqing, 400016, People's Republic of China.
Key Laboratory of Biochemistry and Molecular Pharmacology of Chongqing, Chongqing Medical University, Chongqing, 400016, People's Republic of China.
Stem Cell Res Ther. 2025 Feb 25;16(1):91. doi: 10.1186/s13287-025-04186-9.
This study mainly explores the possible role and mechanism of pyruvate dehydrogenase kinase 4 (PDK4) in the onset and development of Glucocorticoid-induced osteoporosis (GIOP), and seeks potential targets for the treatment of GIOP.
Mesenchymal stem cells (MSCs) were treated with osteogenic induction medium. An in vitro osteogenic damage model was established by exposing MSCs to a high concentration (10 M) of dexamethasone (DEX). Osteogenic markers were measured with real-time quantitative polymerase chain reaction, western blot, alkaline phosphatase staining, and Alizarin Red S staining. Ferroptosis markers were assessed through reactive oxygen species (ROS) fluorescent probe, transmission electron microscopy, and measurement of malondialdehyde (MDA). The potential mechanism was investigated using RT-qPCR, western blot, lysosomal probes, molecular docking, and other analytical approaches. The role of PDK4 was validated by using a GIOP rat model, micro-computed tomography and Masson's trichrome staining.
High concentrations (10 M) of DEX inhibited osteogenic differentiation in C3H10T1/2 cells, and PDK4 exhibited the opposite effect. PDK4 partially reversed the osteogenic inhibitory effect of DEX both in vivo and in vitro. DEX caused mitochondrial shrinkage and disappearance of cristae in C3H10T1/2 cells, as well as an increase in total iron, ROS, MDA contents, and the level of ferroptosis key factors. These changes were partially weakened by PDK4. The ferroptosis inhibitor ferrostatin-1 partially blocked the inhibitory effect of DEX, while ferroptosis inducer RSL3 inhibited osteogenic differentiation and weakened the reversal effect of PDK4. DEX reduced the protein level of PDK4, which was partially weakened by Bafilomycin A1. The molecular docking results showed that DEX can directly bind with PDK4.
PDK4 can enhance the osteogenic differentiation ability of MSCs and bone mass of GIOP rats. DEX may promote the degradation of PDK4 via lysosome pathway, through which to weaken the osteogenic ability of MSCs by increasing ferroptosis. PDK4 may become a potential target for improving GIOP.
本研究主要探讨丙酮酸脱氢酶激酶4（PDK4）在糖皮质激素性骨质疏松症（GIOP）发病及发展过程中的可能作用及机制，寻找治疗GIOP的潜在靶点。
用成骨诱导培养基处理间充质干细胞（MSCs）。通过将MSCs暴露于高浓度（10 μM）地塞米松（DEX）建立体外成骨损伤模型。用实时定量聚合酶链反应、蛋白质免疫印迹法、碱性磷酸酶染色和茜素红S染色检测成骨标志物。通过活性氧（ROS）荧光探针、透射电子显微镜和丙二醛（MDA）测定评估铁死亡标志物。采用逆转录-定量聚合酶链反应、蛋白质免疫印迹法、溶酶体探针、分子对接等分析方法研究潜在机制。通过GIOP大鼠模型、显微计算机断层扫描和Masson三色染色验证PDK4的作用。
高浓度（10 μM）DEX抑制C3H10T1/2细胞的成骨分化，而PDK4表现出相反的作用。PDK4在体内和体外均部分逆转了DEX的成骨抑制作用。DEX导致C3H10T1/2细胞线粒体收缩和嵴消失，以及总铁、ROS、MDA含量和铁死亡关键因子水平升高。这些变化被PDK4部分减弱。铁死亡抑制剂铁抑素-1部分阻断了DEX的抑制作用，而铁死亡诱导剂RSL3抑制成骨分化并减弱了PDK4的逆转作用。DEX降低了PDK4的蛋白水平，巴弗洛霉素A1部分减弱了这种降低。分子对接结果表明DEX可直接与PDK4结合。
PDK4可增强MSCs的成骨分化能力及GIOP大鼠的骨量。DEX可能通过溶酶体途径促进PDK4的降解，从而通过增加铁死亡削弱MSCs的成骨能力。PDK4可能成为改善GIOP的潜在靶点。
