MGST1 Suppresses Ferroptosis in Nucleus Pulposus Cells and Attenuates Intervertebral Disc Degeneration by Regulating GPX4.

Thonningianin a mitigates intervertebral disc degeneration by inhibiting ferroptosis via chelating Fe2+ and regulating the adenosine monophosphate-activated protein kinase (AMPK)/ nuclear factor erythroid 2-related factor 2 (Nrf2)/ glutathione peroxidase 4 (GPX4) pathway.

BACKGROUND Oxidative stress and ferroptosis play critical roles in the pathogenesis of intervertebral disc degeneration (IVDD). Thonningianin A (TA) is a complex polyphenolic ellagitannin found in plants like Thonningia sanguinea, and it exhibits free radical scavenging, anti-superoxide anion generation and metal-chelating activities. However, whether it can inhibit oxidative stress, ferroptosis and the progression of IVDD remains unclear. PURPOSE This study aimed to elucidate the molecular mechanism by which TA alleviates IVDD, specifically regarding oxidative stress and ferroptosis, and to validate these mechanisms in both cellular and animal models. METHODS An RSL3-induced nucleus pulposus cells (NPCs) ferroptosis model was established, with rescue using Fer-1, DFO and various concentrations of TA along with siRNA validation. Ferroptosis, oxidative stress and extracellular matrix (ECM) related proteins were assessed by western blot, immunofluorescence, fluorescent probes, molecular docking, molecular dynamics simulations and DFT binding energy analysis. In vivo, a rat tail puncture IVDD model was treated with TA or Fer-1, and evaluated by X-ray, MRI, Safranin-O/fast green (S-O) staining, Hematoxylin and Eosin (HE) staining and immunohistochemistry. RESULTS Mechanistic studies revealed that TA activates adenosine monophosphate-activated protein kinase (AMPK) phosphorylation and promotes the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and subsequently upregulates the expression of glutathione peroxidase 4 (GPX4), thereby inhibiting oxidative stress, ECM degradation and ferroptosis. Additionally, TA modulates intracellular iron homeostasis by chelating Fe²⁺, thereby further attenuating ferroptosis. In a rat model, local intradiscal injection and intraperitoneal administration of TA effectively inhibited the progression of IVDD. CONCLUSION TA inhibits oxidative stress, ECM degradation and ferroptosis in NPCs by activating the AMPK/Nrf2/GPX4 axis and chelating Fe²⁺, thereby suppressing the progression of IVDD.

The USP5-MATN3 axis in nucleus pulposus cell senescence: A Deubiquitination mechanism protecting against intervertebral disc degeneration.

This study clarifies the molecular mechanism by which the USP5/MATN3 axis regulates cellular senescence and affects IVDD progression, opening up new potential targets for the intervention strategy of IVDD.

Catalpol ameliorates intervertebral disc degeneration by suppressing NP cell Pyroptosis via the NF-ĸB pathway.

Intervertebral disc degeneration (IDD) is a prevalent degenerative disorder and a leading cause of low back pain. Catalpol (CAT) possesses recognized anti-inflammatory and antioxidant properties and shows therapeutic potential for various inflammatory diseases; however, its role in IDD remains unclear. This study aimed to investigate the protective effects of CAT against IDD and to elucidate its underlying mechanism. The study employed both in vitro and in vivo experimental models. The effects of CAT on IDD progression were assessed, with a focus on nucleus pulposus (NP) cell pyroptosis. Mechanistic investigations were conducted to examine the involvement of the NF-κB/NLRP3-mediated pyroptotic pathway, including the nuclear translocation of phosphorylated P65 (p-P65). The dependence of CAT's action on this pathway was further verified through P65 overexpression experiments. CAT was demonstrated to alleviate IDD in experimental models. It exerted its protective effect by inhibiting pyroptosis in NP cells. Mechanistically, CAT blocked the nuclear translocation of p-P65, thereby suppressing the NF-κB/NLRP3-mediated pyroptotic pathway. The reversal of CAT's protective effects upon P65 overexpression confirmed that its action is dependent on this pathway. This study reveals that CAT alleviates IDD by directly targeting P65 to inhibit NP cell pyroptosis via the NF-κB/NLRP3 pathway. These findings identify CAT as a novel therapeutic candidate and provide a mechanistic insight for the treatment of intervertebral disc degeneration.

Nystose treats intervertebral disc degeneration via the Nrf2 axis: a focus on oxidative stress and ferroptosis

Background Intervertebral disc degeneration (IDD) is the primary aetiology of chronic lower back pain and is driven by factors such as oxidative stress and nucleus pulposus (NP) cell dysfunction. Nystose (Nys), a key active oligosaccharide derived from Morinda officinalis How., has shown potential in treating degenerative diseases; however, its specific effect and underlying mechanism of action in IDD remain largely unexplored. Purpose This study aimed to investigate the therapeutic potential of Nys in IDD and elucidate whether its protective effects are mediated by the nuclear factor erythroid 2-related factor 2 (Nrf2)/haem oxygenase-1 (HO-1)/glutathione peroxidase 4 (GPX4) signalling axis. Methods Network pharmacology was used to identify potential targets of Nys. In vitro, Nys–Nrf2 binding was predicted via molecular docking and thermal shift assays, and the effects of this interaction on ROS levels, ferroptosis, and extracellular matrix (ECM) metabolism were evaluated in oxidatively stressed NP cells. These effects were verified using Nrf2 siRNA. The in vivo efficacy of Nys was assessed in a lumbar spine instability (LSI) mouse model. Results Network pharmacology identified Nrf2 as a core regulatory node. Nys suppressed ROS production and ferroptosis via iron metabolism regulation, which was driven by Nys binding to Nrf2 to promote its nuclear translocation. Nrf2 silencing abolished the ability of Nys to protect the ECM and exert antiferroptotic effects. In vivo testing confirmed that Nys shields the intervertebral disc from LSI-mediated damage through robust Nrf2 activation. Conclusion Nystose alleviates IDD by activating the Nrf2/HO-1/GPX4 signalling axis, which in turn inhibits oxidative stress and ferroptosis to restore ECM homeostasis. Nys represents a promising therapeutic candidate for IDD intervention.

MANF safeguards mitochondria-associated endoplasmic reticulum membrane integrity in nucleus pulposus-derived mesenchymal stem cells to maintain homeostasis of the intervertebral disc.

BACKGROUND Intervertebral disc (IVD) degeneration (IDD) is a leading cause of low back pain, with limited treatment options. The degenerative disc's harsh microenvironment promotes nucleus pulposus-derived mesenchymal stem cells (NP-MSCs) death and hinders self repair. Mesencephalic astrocyte-derived neurotrophic factor (MANF), an atypical neurotrophic factor, has protective effects in degenerative diseases. However, its role in IDD is unclear. METHODS Assessment of MANF expression was conducted in both human nucleus pulposus tissues and a rat IVD puncture model. An in vitro model of degeneration was established by acid treatment of NP-MSCs, and the functional role of MANF was explored through its knockdown and overexpression. RNA sequencing was employed to identify downstream targets. The therapeutic potential of MANF-overexpressing NP-MSCs was evaluated in a rat puncture model. RESULTS MANF expression was markedly downregulated in degenerated IVD tissues from both human patients and rat models. Correspondingly, in vitro experiments demonstrated that MANF knockdown exacerbated, while its overexpression mitigated, acid-induced apoptosis of NP-MSCs. Mechanistically, MANF attenuated mitochondrial dysfunction and ER stress of NP-MSCs under acidic conditions by maintaining MAM integrity, as demonstrated by the complete abolition of this protection upon treatment with the MAM uncoupler FATE1. Transcriptomic analysis and subsequent validation identified receptor expression-enhancing protein 1 (REEP1) as a critical downstream effector through which MANF safeguards MAM integrity. We further elucidated that MANF upregulates REEP1 expression by directly inhibiting miR-33b-5p. In vivo, transplantation of MANF-overexpressing NP-MSCs effectively attenuated IDD in a rat model. CONCLUSION MANF protected NP-MSCs from acidosis by sustaining MAM integrity via the MiR-33b-5p/REEP1 axis. These findings reveal MANF's mechanism and therapeutic potential for IDD.

Integrated bioinformatics and experimental validation reveal that kaempferol ameliorates intervertebral disc degeneration via dual anti-inflammatory and anti-aging pathways.