(Z)-Ligustilide alleviates intervertebral disc degeneration by suppressing nucleus pulposus cell pyroptosis via Atg5/NLRP3 axis.

Abstract

Intervertebral disc degeneration (IVDD) represents one of the most prevalent degenerative disorders, significantly impairing quality of life and overall health. The inflammatory cascade and dysregulated degradation of the extracellular matrix (ECM) triggered by pyroptosis are considered key mechanisms underlying the pathogenesis of IVDD. Research has highlighted the potential of Chuanxiong Rhizoma (CX), a traditional Chinese medicine, in exerting anti-pyroptotic effects; nevertheless, the exact mechanisms and pathways through which it modulates inflammation, as well as its potential role in the context of IVDD, remain unknown. Network pharmacology analysis was initially employed to identify the principal components and targets of Chuanxiong Rhizoma (CX) in the treatment of IVDD, ultimately selecting LIG as the key active ingredient responsible for its therapeutical effect. To explore the therapeutic effects of LIG on IVDD, we established a rat acupuncture model to simulate IVDD in vivo. Additionally, we used lipopolysaccharide (LPS) and adenosine triphosphate (ATP) to induce NPC degeneration model in vitro. In vitro experiments revealed that LIG treatment promotes the expression of anabolic markers such as Collagen II and Aggrecan while inhibiting the expression of catabolic markers MMP9 and MMP13 in nucleus pulposus cells (NPCs). Furthermore, LIG was also shown to inhibit cell pyroptosis and the secretion of inflammatory cytokines, which was mediated by NLRP3/caspase-1/GSDMD-N activation. Molecular docking and co-immunoprecipitation further demonstrated that LIG acts as a ligand for the Atg5 protein, inhibiting its degradation and promoting its interaction with the NLRP3 protein, ultimately leading to the suppression of pyroptosis activation in NPCs. It was also found that knocking down Atg5 reverses the protective effects of LIG and exacerbates pyroptosis-mediated inflammation in IVDD. In addition, in vivo experiments also showed that LIG delayed acupuncture-mediated IVDD development. Therefore, this paper confirmed that LIG has the ability to protect NPCs against pyroptosis through Atg5/NLRP3 axis and exert its therapeutic application to ameliorate disc degeneration in vivo. This may shed new insights into the role of LIG in IVDD treatment and offer a mechanistic basis for targeting NLRP3-mediated pyroptosis.