软骨细胞线粒体功能损伤在AGEs/RAGE致骨关节炎病变中的作用及相关机制

Previous studies have found that mitochondrial function in osteoarthritis（OA） with patients or animals significantly impaired, and is closely related to the development and progression of OA. The mechanism was related to promoting the apoptosis of chondrocytes, and damaging the imbalance of matrix anabolic and inflammatory. Previous studies have shown that age and age-related peroxisome proliferator-activated receptor-λ (PPAR-λ) down expression were primarily responsible for mitochondrial dysfunction. As we know, the most significant changing was the accumulation of advanced glycation end products (AGEs) with aging; what more, in our previous studies we have demonstrated AGEs significantly down-regulated PPAR-λin OA. Therefore, hypothesized that mitochondrial dysfunction might played a key role in AGEs-induced OA. In this study, we would prepared AGEs-damaged cell and animal model to verify the damage effect of AGEs on the mitochondrial function and study the mechanism by blockingwhether PPAR-λ、ER stress、ROS、MAPKs or NF-κB.This study will indicate that the combination of mitochondria-targeting drugs and with AGEs synthesis and crosslinking inhibitors would completely block the action of AGEs, protect mitochondrial function, and provide new ideas for the prevention and treatment of OA.

线粒体功能在骨关节炎（OA）患者明显受损，且通过诱导软骨细胞凋亡、基质代谢失衡、炎症等促进OA发展。OA时线粒体损伤原因及机制不明，呈持续进行性损伤，目前研究显示主要与年龄及年龄相关性过氧化物酶体增殖物激活受体-λ (PPAR-λ)下调有关，而随着年龄增长体内最显著变化即为糖基化终末产物（AGEs）大量堆积。在我们前期研究中发现，AGEs与其受体RAGE结合后可显著诱导PPAR-λ下调损伤软骨细胞，这提示AGEs/RAGE可能通过PPAR-λ诱导线粒体功能损伤。在本项目中拟制备AGEs损伤细胞及动物模型，观察AGEs对线粒体的损伤作用，同时对PPAR-λ、内质网应激、氧化应激、MAPKs、NF-κB等重要靶点及下游效应分子进行干预及检测，以明确相关机制。该研究结果或将提示开发基于线粒体的靶向药物与AGEs合成及交联抑制剂联合应用将彻底阻断AGEs作用，保护线粒体功能，为OA防治提供新思路。

线粒体功能在骨关节炎（OA）患者明显受损，且通过诱导软骨细胞凋亡、基质代谢失衡、炎症等促进OA发展。OA时线粒体损伤原因及机制不明，呈持续进行性损伤。目前研究显示主要与年龄及年龄相关性过氧化物酶体增殖物激活受体-γ (PPAR-γ)下调有关，而随着年龄增长体内最显著变化即为糖基化终末产物（AGEs）大量堆积。在我们前期研究中发现，AGEs下调PPAR-γ损伤软骨细胞，我们提出并验证假说：AGEs可能通过PPAR-λ诱导软骨细胞线粒体损伤。在本研究中，我们发现AGEs可以显著下调PPAR-γ的表达，线粒体功能损伤，从而诱导TNF-α和MMP-13表达增加，而PPAR-γ的天然激动剂Curcumin可有效保护软骨细胞功能。我们同时进一步深入研究了 PPAR-γ辅助活化因子-1а(PGC-1а）在AGEs诱导OA病变中的作用。我们发现AGEs降低磷酸化AMPKα表达进而诱导软骨细胞SIRT1和PGC-1α下调。与AGEs处理的软骨细胞相比，过表达AMPKα、SIRT1或PGC-1α逆转了膜电位；siRNA AMPKα、SIRT1或PGC-1α则增强了AGEs诱导的线粒体膜电位的降低。同时，AGEs诱导软骨细胞线粒体DNA含量、线粒体质量和ATP生成量均降低，并均被过表达AMPKα、SIRT1或PGC-1α所逆转。过表达AMPKα/SIRT1/PGC-1α通路后，可以显著抑制AGEs诱导的分解代谢反应、软骨细胞炎症和氧化应激，同时基于AMPKα的激动作用Curcumin显著抑制AGEs诱导的OA病变。至此本项目研究结果表明AGEs通过下调PPAR-γ/AMPKα/SIRT1/PGC-1α通路，诱导软骨细胞线粒体功能损伤，进而促进OA病变的发生发展。本项目研究结果OA临床治疗提供了一定的指导意义。