氧化应激诱导的线粒体自噬在椎间盘退变中的作用及机制研究

Oxidative stress damage plays a crucial role in the pathogenesis of intervertebral disc degeneration. It was demonstrated that the mitochondrial pathway of apoptosis induced by oxidative stress was involved in disc cell death and intervertebral disc degeneration. Our further study found that oxidative stress could induce mitophagy. It is hypothesized that oxidative stress induced-mitophagy may play a role in the pathogenesis of intervertebral disc degeneration. In this study, we will investigate the relation of mitophagy, oxidative stress and intervertebral disc degeneration. Using inhibitors and activators of mitophagy, we investigate the role of mitophagy in oxidative stress-induced intervertebral disc cell death. Furthermore, we explore the interactive relationship in the regulation of oxidative stress-induced mitophagy between Keap1/Nrf2 pathway and HIF1-α/NDUFA4L2 pathway, which are the regulating center of oxidative stress. Then, using RNA interference and gene transfection, we will investigate the effects of NDUFA4L2 on oxidative stress-induced mitophagy in vitro and in vivo. In this study, we will systematically analyze the role of oxidative stress-induced mitophagy in the pathogenesis of intervertebral disc degeneration. This study will provide the theoretical and experimental evidence for clarifying the pathogenesis of intervertebral disc degeneration, and raise a new idea for the prevention and treatment of intervertebral disc degeneration.

氧化应激在椎间盘退变过程中具有重要作用。我们研究发现氧化应激诱导的线粒体凋亡途径参与椎间盘退变过程。进一步的预实验发现氧化应激可诱导椎间盘细胞线粒体自噬，我们推测氧化应激可能通过线粒体自噬通路启动椎间盘细胞自噬性死亡从而导致椎间盘退变。本课题拟利用人体标本和动物模型在组织学水平检测线粒体自噬与氧化应激的关系以及其在椎间盘退变中的作用；在细胞水平利用线粒体自噬的抑制剂和激动剂研究线粒体自噬在氧化应激诱导椎间盘细胞死亡中的作用；研究氧化应激调节中心HIF1-α/NDUFA4L2与Keap1/Nrf2通路在调控氧化应激诱导椎间盘细胞线粒体自噬过程中的作用和交互关系；通过基因干扰和过表达技术，在体外研究NDUFA4L2对椎间盘细胞氧化应激诱导线粒体自噬的影响，在体内研究NDUFA4L2过表达能否延缓椎间盘退变过程。系统研究氧化应激诱导的线粒体自噬在椎间盘退变中作用，为椎间盘退变的防治开辟新思路。

椎间盘退变的主要病理机制是髓核细胞程序性凋亡。氧化应激是椎间盘退变的一个重要原因。在椎间盘退变中，线粒体自噬是否由强氧化应激诱导尚待确定。本研究旨在探讨氧化应激与线粒体自噬的关系，以更好地了解椎间盘退变的体内外机制。为此，我们从人椎间盘中获得原代髓核细胞，然后将其暴露于TBHP（羟基过氧化氢）。我们观察到氧化应激诱导线粒体自噬导致髓核细胞凋亡。抑制线粒体自噬减轻髓核细胞的凋亡。有趣的是，TBHP通过抑制HIF-1α/NDUFA4L2通路诱导线粒体自噬。而线粒体NDUFA4L2的上调减轻氧化应激诱导的线粒体自噬。此外，HIF-1α和NDUFA4L2在椎间盘退变组织中的表达水平降低。综上所述，这些结果表明上调NDUFA4L2可以通过抑制过度的线粒体自噬来改善髓核细胞的凋亡，从而最终缓解椎间盘退变。这些发现首次表明NDUFA4L2和线粒体自噬可能是椎间盘退变的潜在治疗靶点。