A CREB5-NR4A1 checkpoint protects against disc degeneration by controlling ferroptosis.

Intervertebral disc degeneration (IDD) is a major contributor to low back pain (LBP), with ferroptosis recently recognized as a key mechanism underlying its progression.This study investigates the protective role of cAMP response element-binding protein 5 (CREB5) in IDD, focusing on its capacity to preserve extracellular matrix (ECM) integrity and to modulate ferroptosis and mitochondrial oxidative stress through activation of the NR4A1-PGC-1α signaling axis. An integrated approach combining bioinformatics, quantitative RT-PCR (qRT-PCR), and Western blotting was employed to identify ferroptosis-associated gene alterations in IDD. The effects of CREB5 overexpression and knockdown on tert-butyl hydroperoxide (TBHP)-induced ferroptosis and extracellular matrix (ECM) remodeling in nucleus pulposus (NP) cells were evaluated. Mechanistic pathways were dissected through immunoprecipitation, immunofluorescence, and Western blot analyses. Furthermore, the therapeutic efficacy of CREB5 was assessed in a rat model of IDD via radiographic and histological evaluations. CREB5 expression was significantly reduced in human degenerative discs (-0.41, 95% CI [-0.48, -0.34]; P < 0.001). In oxidatively stressed NP cells, CREB5 overexpression restored the anti-ferroptotic enzyme GPX4 (0.52, 95% CI [0.44, 0.60]; P < 0.001) and suppressed ACSL4 induction (-0.90, 95% CI [-0.98, -0.82]; P < 0.001), accompanied by marked reductions in intracellular Fe²⁺ (-2.52, 95% CI [-2.70, -2.34]; P < 0.001). Mechanistically, CREB5 directly activated NR4A1 (0.86, 95% CI [0.70, 1.02]; P = 0.001), thereby promoting NR4A1-dependent transcription of PGC-1α (2.13, 95% CI [1.90, 2.35]; P < 0.001) and restoring mitochondrial antioxidant capacity. In vivo, CREB5 delivery preserved disc height (42.84, 95% CI [31.04, 54.65]; P < 0.001) and reduced lipid peroxidation (-1.00, 95% CI [-1.12, -0.88]; P < 0.001). CREB5 functions as a transcriptional checkpoint that limits ferroptosis via the NR4A1-PGC-1α axis and maintains structural integrity of the intervertebral disc.