Sestrins-mTOR-TFE3轴调控自噬-溶酶体功能在椎间盘退变中的作用及其机制研究

Intervertebral disc degeneration (IDD) is commonly regarded as an important cause of low back pain. Autophagy dysfunction contributes to the pathogenesis of IDD. Autophagy, regulated by many extracellular factors which are implicated in the pathogenesis of IDD, is induced in nucleus pulposus (NP). Lysosome is established as the important sites of intracellular autophagy. TFE3 plays an important role in maintaining lysosomal function and autophagy. Dysfunction of TFE3 and blockage of autophagic flux are linked to various degenerative diseases. The pilot experiment shows that the nuclear translocation of TFE3 and autophagy were inhibited in starvation-induced degenerative NP cells. There existed evidence that Sestrins-mTOR signaling pathways could influence the TFE3 activity. Dysfunction of Sestrins-mTOR signaling pathways in the degenerative NP cells were found in our previous study. These results indicate that blockage of autophagy flux by dysfunction of Sestrins-mTOR-TFE3 signaling pathway may be an important mechanism in NP cell dysfunction and progression of IDD. We will explore these changes by tissue analysis, cell experiment and disc degeneration in a rat-tail model. This study aims to assess the relevance network of Sestrins-mTOR-TFE3 signaling pathway regulating autophagy-lysosome dysfunction in the pathogenesis of IDD and to provide new insights for the IDD prevention and treatment.

椎间盘退变(IDD)是导致下腰痛的主要原因,自噬功能紊乱是IDD发生的重要机制之一。研究证实多种IDD危险因素可诱发髓核(NP)细胞内自噬反应，溶酶体是该反应过程的中枢细胞器，TFE3作为协调溶酶体功能及自噬反应的主要因子，其功能障碍致自噬流受阻是多种退行性疾病的关键环节。我们前期研究发现饥饿刺激下的退变NP细胞内TFE3核转位和自噬反应被明显抑制，且Sestrins-mTOR轴作为TFE3功能状态的重要调控机制，其在退变NP细胞内存在明显的功能缺失，提示Sestrins-mTOR-TFE3轴紊乱致自噬流阻断可能是NP细胞功能障碍和IDD进展的重要机制。本项目拟进一步通过临床标本检测、细胞实验及鼠尾IDD模型验证，明确Sestrins-mTOR-TFE3轴调控自噬-溶酶体功能障碍参与IDD进展中的作用机制及相关分子网络，为IDD的防治提供新的思路。

椎间盘退变(IDD)是导致下腰痛的主要原因,自噬功能紊乱是IDD发生的重要机制之一。研究证实多种IDD危险因素可诱发髓核(NP)细胞内自噬反应，溶酶体是该反应过程的中枢细胞器，其功能障碍致自噬流受阻是多种退行性疾病的关键环节。本项目在自噬溶酶体调节椎间盘退变的机制研究上，探索了自噬溶酶体功能调控AIM2炎性小体活化的关键调控机制，以及研究自噬流变化对AIM2炎性小体活性的调控机制，。此外，研究了G3BP1调控溶酶体功能及铁死亡在椎间盘退变中的作用机制。结论表明，AIM2干扰明显降低髓核组织内NLRP3蛋白、caspase1蛋白及IL-1β水平，并最终提高髓核组织内二型胶原和蛋白聚糖水平。自噬-mTOR-TFE3轴可调控AIM2炎性小体活化，良好的自噬溶酶体功能对细胞内AIM2炎性小体水平的调节具有重要意义。完整自噬流对AIM2水平有调控作用，恢复受损自噬流是抑制AIM2炎性小体及延缓IDD进展的重要靶点。此外，G3BP1可通过调控溶酶体功能调节溶酶体自噬活性，继而提升NP细胞内脂质过氧化应激适应能力，从而影响NP细胞铁死亡结局。该项目的顺利实施不仅明确了椎间盘退变过程中AIM2炎症小体活化机制与溶酶体自噬流的关系，也为相关治疗靶点提供了重要干预策略，为探索椎间盘损伤修复策略提供了重要理论依据。