Wang Zhao-Jun, Wang Wei, Jia Kai-Xing, Zhang Hai-Bin, Wang Jian-An, Chen Cheng
Department of Trauma Repair reconstructive surgery, Fenyang Hospital of Shanxi Province, Fen yang Hospital Affiliated to Shanxi Medical University, Fenyang, 032200, Shanxi, People's Republic of China.
The 926th Hospital of the Joint Logistics Support Force of the People's Liberation Army of China, PLA, Kaiyuan, 661600, Yunnan, People's Republic of China.
J Orthop. 2025 May 19;66:204-212. doi: 10.1016/j.jor.2025.05.022. eCollection 2025 Aug.
BACKGROUND: Advanced Glycation End Products (AGEs), which accumulate in metabolic syndrome patients and the elderly, are implicated in osteoarthritis (OA) pathogenesis. Peroxisome proliferator-activated receptor-γ (PPARγ), a nuclear receptor, has emerged as a potential therapeutic target for OA. This study investigates the molecular mechanisms by which PPARγ regulates AGEs-induced apoptosis and autophagy in human chondrocytes. METHODS: Primary human chondrocytes were exposed to AGEs, either with or without the PPARγ agonist pioglitazone, as well as specific inhibitors targeting MAPK and NF-κB pathways. Autophagy levels were assessed via Western blot analysis of LC3-II, transmission electron microscopy (TEM), and GFP-LC3 imaging. Apoptosis was evaluated by measuring cleaved caspase-3, cleaved PARP, and FITC Annexin V using Western blot and flow cytometry. PPARγ expression was quantified via real-time PCR, while MAPK and NF-κB pathway activation was examined by analyzing phosphorylated ERK, JNK, p38, and IκBα levels. Additionally, MMP-13 and TNF-α expression was measured using ELISA. RESULTS: High-dose AGEs treatment in human chondrocytes led to increased apoptosis, reduced autophagy, downregulation of PPARγ, and activation of MAPK and NF-κB pathways. Pioglitazone treatment elevated autophagy marker LC3-II while suppressing phosphorylation of MAPK components ERK and p38. Notably, inhibitors of JNK and p38 partially reversed AGEs-induced PPARγ suppression and restored autophagy. AGEs also activated the NF-κB pathway, an effect counteracted by pioglitazone. Furthermore, NF-κB inhibition enhanced autophagy in AGEs-treated chondrocytes. Compared to AGEs alone, pioglitazone, specific MAPK inhibitors (SP600125 and SB203580, but not PD98059), and NF-κB inhibitors reduced MMP-13 and TNF-α expression. CONCLUSIONS: PPARγ activation via pioglitazone mitigates AGEs-driven chondrocyte apoptosis and reinstates autophagy by regulating MAPK and NF-κB signaling. These results suggest that PPARγ agonism could serve as a dual-target therapeutic approach for OA, with pioglitazone emerging as a potential disease-modifying agent. Further clinical research is needed to confirm its therapeutic benefits in OA management.
背景：晚期糖基化终产物（AGEs）在代谢综合征患者和老年人中蓄积，与骨关节炎（OA）的发病机制有关。过氧化物酶体增殖物激活受体γ（PPARγ）作为一种核受体，已成为OA潜在的治疗靶点。本研究探讨PPARγ调节AGEs诱导人软骨细胞凋亡和自噬的分子机制。 方法：将原代人软骨细胞暴露于AGEs中，同时或不同时添加PPARγ激动剂吡格列酮，以及靶向MAPK和NF-κB通路的特异性抑制剂。通过对LC3-II进行蛋白质印迹分析、透射电子显微镜（TEM）和GFP-LC3成像评估自噬水平。通过蛋白质印迹和流式细胞术检测裂解的半胱天冬酶-3、裂解的聚（ADP-核糖）聚合酶（PARP）和FITC膜联蛋白V来评估凋亡。通过实时PCR定量PPARγ表达，通过分析磷酸化的细胞外信号调节激酶（ERK）、应激活化蛋白激酶（JNK）、p38和IκBα水平来检测MAPK和NF-κB通路的激活。此外，使用酶联免疫吸附测定（ELISA）测量基质金属蛋白酶-13（MMP-13）和肿瘤坏死因子-α（TNF-α）的表达。 结果：高剂量AGEs处理人软骨细胞导致凋亡增加、自噬减少、PPARγ下调以及MAPK和NF-κB通路激活。吡格列酮处理可提高自噬标志物LC3-II水平，同时抑制MAPK组分ERK和p38的磷酸化。值得注意的是，JNK和p38抑制剂部分逆转了AGEs诱导的PPARγ抑制并恢复了自噬。AGEs还激活了NF-κB通路，吡格列酮可抵消这一作用。此外，抑制NF-κB可增强AGEs处理的软骨细胞中的自噬。与单独使用AGEs相比，吡格列酮、特异性MAPK抑制剂（SP600125和SB203580，但不包括PD98059）和NF-κB抑制剂可降低MMP-13和TNF-α的表达。 结论：通过吡格列酮激活PPARγ可减轻AGEs驱动的软骨细胞凋亡，并通过调节MAPK和NF-κB信号通路恢复自噬。这些结果表明，PPARγ激动作用可作为OA的双靶点治疗方法，吡格列酮有望成为一种潜在的病情改善药物。需要进一步的临床研究来证实其在OA治疗中的益处。
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