Objective This study aimed to investigate the role of the STAT3/POSTN/GSTP1/JNK axis in ferroptosis and extracellular matrix (ECM) metabolic imbalance in nucleus pulposus cells (NPCs) during intervertebral disc degeneration (IDD) and to explore therapeutic strategies targeting this axis.
Methods Using integrated multiomics sequencing, transcriptional regulation assays (chromatin immunoprecipitation, dual‑luciferase reporter), protein interaction analysis (CoIP), and other molecular biology approaches, we systematically elucidated the regulatory role of the STAT3/POSTN/GSTP1/JNK axis in ferroptosis of NPCs during IDD. Functional validation was performed in POSTN‑edited cell and rat models as well as in a needle‑puncture‑
induced rat IDD model. A small‑molecule candidate targeting this axis was identified through virtual screening, molecular docking, and molecular dynamics simulations.
Results Periostin (POSTN) expression increased during ferroptosis and induced ferroptosis and ECM metabolic imbalance in NPCs in a concentration- and time-dependent manner. STAT3 was identified as a transcriptional regulator of POSTN and functionally coupled with POSTN to form a self-amplifying positive feedback loop, accelerating ferroptosis progression. Furthermore, POSTN impaired the binding of the GSTP1/JNK complex, leading to the depletion of cellular glutathione. Chemical screening identified pristimerin (PN) as a potential GSTP1-targeting compound, targeting the STAT3/POSTN/GSTP1/JNK axis and delaying IDD progression.
Conclusion This study identified the important role of the STAT3/POSTN/GSTP1/JNK axis in regulating ferroptosis and ECM metabolism in NPCs and highlighted PN as a promising candidate therapeutic agent for IDD. These findings provide new insights into the molecular mechanisms underlying IDD and offer new targeted therapeutic avenues for IDD.
Objective Transient receptor potential vanilloid 4 (TRPV4), a mechanosensitive ion channel, has been implicated in intervertebral disc homeostasis; however, its role in autophagy regulation remains unclear. This study aimed to investigate whether agonist-induced TRPV4 activation promotes autophagy and extracellular matrix (ECM) synthesis in rat intervertebral discs.
Methods In vitro, rat nucleus pulposus (NP) cells were treated with the TRPV4 agonist (GSK1016790) under normal, serum-deprived, or interleukin-1β-stimulated conditions. Cell viability, intracellular Ca2+ influx, adenosine monophosphate-activated protein kinase/mammalian target of rapamycin (mTOR) (AMPK/mTOR) pathway, autophagy, ECM metabolism, apoptosis, and senescence were evaluated. In vivo, TRPV4 agonist was injected into the caudal discs subjected to temporary static compression, and disc changes were assessed by radiography, histomorphology, and immunofluorescence.
Results In vitro, agonist-induced TRPV4 activation rapidly increased intracellular Ca2+ influx and enhanced AMPK phosphorylation. A noncytotoxic concentration of the TRPV4 agonist (10 nM) was selected after dose-response testing. Under the inflammatory stress, TRPV4 agonist enhanced autophagy, promoted ECM synthesis, and suppressed apoptosis and senescence, leading to improved NP cell viability. In vivo, TRPV4 agonist treatment preserved radiographic disc height (p<0.01), reduced histomorphological degeneration (p<0.01), and increased expression of COL2A1, Brachyury, p-AMPK (phosphorylated AMPK), and autophagy markers (p<0.01) compared with controls.
Conclusion These findings demonstrated that TRPV4 activation promotes autophagy and ECM synthesis via the AMPK/mTOR pathway in rat discs and attenuates stress-induced degeneration, suggesting TRPV4 as a potential therapeutic target for disc degeneration.
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