IRP2介导的线粒体铁超载在腰椎小关节骨性关节炎中的作用和机制研究

Lumbar facet joint osteoarthritis (LFOA) is one of the most common problems encountered in clinical practice today, with a loss of quality of life and a substantial burden for national health-care system. Despite its clinical and social importance, the detail molecular mechanism of LFOA remains to be elusive. In the preliminary study, we found that gene and protein expression of iron regulatory protein 2 (IRP2) were up-regulated in the lumbar facet joint of LFOA patients. The aim of present study was to investigate the role of IRP2-mediated iron overload in the progression of LFOA..In vitro, IRP2 will be overexpressed by transfecting with recombinant adenovirus containing IRP2-overexpressing plasmid or suppressed by transfecting with IRP2 shRNA lentiviral particles in primary cultured human lumbar chondrocytes to evaluate their response to IL-1β stimulation, biomechanical injury or oxygen deprivation combined with low glucose. In vivo, LFOA will be induced in IRP2 gene knockout mice by using intraarticular injection of adjuvant or uPA to elucidate the function of IRP2 in mouse models of LFOA..This study will elucidate the potential role of IRP2-mediated iron overload in the progression of LFOA and will provide a novel therapeutic target for LFOA.

腰椎小关节骨性关节炎（LFOA）的发病机制目前尚不清楚。预实验结果发现铁调节蛋白2（IRP2）蛋白在人腰椎小关节骨性关节病变中表达上调，而最近的研究显示IRP2可以参与调节线粒体内铁超载的发生。于是我们提出假设：IRP2表达上调可以诱导线粒体铁超载，损伤线粒体功能，从而参与LFOA的发生发展。细胞水平我们在软骨细胞中低表达或高表达IRP2蛋白，观察该蛋白在炎症因子IL-1β、低糖缺氧刺激、生物力学刺激损伤软骨细胞过程中的对线粒体铁超载以及线粒体功能的作用。在整体水平，我们在IRP2基因敲除小鼠中通过腰椎小关节注射弗氏佐剂或尿激酶型纤溶酶原激活物，制备了腰椎小关节的骨性关节炎模型，观察IRP2对腰椎间小关节病变的影响以及相关铁超载的作用机制。本课题将为进一步认识和揭示IRP2介导的线粒体铁超载参与LFOA发生发展的潜在机制提供实验数据。

腰痛是老年人最常见的病症之一，随着社会人口老龄化，其发病率逐年上升。研究发现，腰椎小关节骨性关节炎，作为腰椎退行性疾病的一种，是引起腰痛的重要原因之一，近些年来受到越来越多学者们的重视。腰椎小关节骨性关节炎的发病机制目前尚不清楚。本项目通过体外使用shRNA干扰以及过表达慢病毒载体技术，IL-1β刺激模拟腰椎小关节骨性关节炎中的炎性刺激环境，发现抑制IRP2可减轻炎症对软骨细胞的破坏，激活IRP2可加重炎症对软骨细胞的破坏。通过体外使用shRNA干扰以及过表达慢病毒载体技术，低氧培养刺激模拟腰椎小关节骨性关节炎中的低氧环境，发现抑制IRP2不能显著减轻缺氧对软骨细胞的破坏，激活IRP2可加重缺氧对软骨细胞的破坏。深入研究LFOA的发病机制，为临床上开发更加有效、更具特异性的治疗药物提供理论基础。