IntroductionIntervertebral disc degeneration (IDD) represents one of the primary causes of chronic low back pain, characterized by multifaceted pathophysiological mechanisms1. The intervertebral disc comprises the nucleus pulposus (NP), annulus fibrosus (AF), and cartilaginous endplates, with the NP having a pivotal role in maintaining biomechanical homeostasis2. Stressors including diminished nutrient supply, hypoxia, lactate accumulation, and sustained mechanical loading contribute to NP cell injury3,4,5. Progressive NP cell dysfunction and degradation of the extracellular matrix (ECM) ultimately lead to loss of disc elasticity and structural integrity6. Notably, degenerated discs exhibit increased senescent and fibrotic NP cells7, which secrete pro-inflammatory cytokines that exacerbate ECM catabolism3. Among these, mitochondrial dysfunction is closely associated with cellular inflammation and represents one of the key pathological mechanisms in the initiation and progression of IDD8,9. However, the pathology of IDD is complex and influenced by various intrinsic and extrinsic factors. Comparative analysis between normal and degenerated NP cells may elucidate molecular pathways underlying IDD progression and identify therapeutic targets.In recent years, a growing body of research has demonstrated that RNA-binding proteins (RBPs) have crucial roles in disease pathogenesis10,11. RBPs interact with protein-coding genes, messenger RNAs, and non-coding RNAs to exert diverse biological functions, including regulation of mRNA stability and modulation of non-coding RNA synthesis12. Emerging evidence indicates that diverse RBPs are involved in the regulation of NP function and the progression of IDD13,14. These RBPs influence critical biological processes such as ECM metabolism, inflammatory responses, cellular senescence, apoptosis, and ferroptosis, thereby participating in the molecular regulation of IDD pathogenesis13. Identification of key RBPs that regulate disc degeneration could facilitate the discovery of novel therapeutic targets for molecular interventions in IDD.TDP43 (TAR DNA-binding protein 43), a ubiquitously expressed nuclear RBP, primarily participates in post-transcriptional regulation, RNA splicing, and RNA transport15. Recent studies have revealed that aberrant aggregation and dysfunction of TDP43 are closely associated with neurodegenerative disorders, including amyotrophic lateral sclerosis, frontotemporal dementia, and Alzheimer disease15,16. TDP43 modulates inflammatory responses through regulating the stability of various inflammatory mediators, whereas its pathological aggregation disrupts normal cellular metabolic processes, leading to cellular dysfunction and death17. Research has demonstrated altered subcellular localization of TDP43 under pathological conditions, with cytoplasmic translocation resulting in functional impairment of cellular organelles through accumulated TDP43 (refs. 18,19). Nevertheless, to our knowledge, the precise role and molecular mechanisms of TDP43 in IDD remain to be elucidated.This study identifies TDP43 as a differentially expressed RBP in degenerated and stressed NP cells through comparative transcriptomic analysis. It demonstrates that elevated TDP43 expression correlating with disc degeneration grades in both clinical specimens and animal models. Mitochondrial localization of TDP43 associates with mitochondrial dysfunction and cellular senescence in degenerated NP cells. Mitochondrial-derived vesicles (MDVs), as a selective mechanism for removing mitochondrial components, have an important role in intercellular communication and cellular homeostasis, influencing both the originating and surrounding cells. We aim to investigate whether MDVs have a role in the inflammation and senescence of NP cells. Mechanistically, NP cells secrete TDP43-enriched MDVs that propagate senescence phenotypes and amplify inflammatory responses in recipient cells. Genetic and pharmacological inhibition of TDP43 in vesicles alleviates cellular senescence and decelerates IDD progression in vitro and in vivo. Our findings reveal the pathological role of TDP43 and propose TDP43 as a novel therapeutic target for IDD intervention.Materials and methodsTissue samplesAll involved experiments were conducted according to the ethical policies and procedures approved by the Ethics Committee of Tongji Medical College, Huazhong University of Science and Technology. Human NP specimens were obtained during discectomy procedures performed as part of spinal fusion surgery. Collection strictly adhered to the Declaration of Helsinki, with preoperative written informed consent from all patients. Preoperative MRI scans (n = 12 per grade) classified disc degeneration severity using the Pfirrmann grading system (grades I–V), characterized radiographically as follows: grade I: homogeneous hyperintensity (bright white), indicating intact hydration; grade II: discernible NP/AF boundary, despite emerging inhomogeneity; grade III: grayish NP signal intensity with complete loss of NP/AF demarcation; grade IV: marked hypointensity (dark gray/black) with initial disc space narrowing; grade V: structural disintegration featuring obliterated disc space and indistinct NP/AF architecture. All specimens were immediately preserved via immersion in 4% paraformaldehyde or cryopreservation in liquid nitrogen for subsequent analysis.Cell cultureHuman NP cells were isolated from surgically resected NP specimens through enzymatic dissociation. Primary cells were maintained in complete culture medium consisting of DMEM/F-12 supplemented with 15% fetal bovine serum (Cell-Box, China) under standard culture conditions (37 °C, 5% CO2). The isolation protocol comprised sequential steps: first, specimens underwent triple PBS washing cycles to remove blood contaminants; second, tissue fragmentation using sterile surgical scissors; third, incubation with 0.25% type II collagenase under sterile conditions at 37 °C for 4 h and sequential PBS washes (×2) followed by centrifugation at 250 × g for 5 min to pellet digested cells. Finally, cells were resuspended in fresh DMEM/F-12 medium and underwent medium renewal every 72 h. Experimental procedures utilized second-passage (P2) cells to minimize phenotypic drift associated with prolonged in vitro expansion.Statistical analysisData analysis was performed using GraphPad Prism 8 (La Jolla, CA, USA), with results expressed as mean ± standard deviation (SD). Intergroup differences were analyzed using two-tailed unpaired t tests for pairwise comparisons. Multigroup analyses used one-way or two-way analysis of variance with Tukey’s post hoc test. Statistical significance thresholds were set at the 0.05 level (*P