2. Academic Validation
  3. Low-dose valproic acid ameliorates osteoporosis by restoring redox homeostasis and suppressing ferritinophagy-dependent ferroptosis via EZH2/H3K27me3 signaling

Low-dose valproic acid ameliorates osteoporosis by restoring redox homeostasis and suppressing ferritinophagy-dependent ferroptosis via EZH2/H3K27me3 signaling

  • Free Radic Biol Med. 2025 Sep 13:241:76-89. doi: 10.1016/j.freeradbiomed.2025.09.023.
Yifan Gu 1,  Ziru Wang 2,  Kun Wang 2,  Yicong Wang 2,  Yiheng Li 2,  Shuai Jiang 2,  Yu Zheng 2,  Run Feng 2,  Min Yang 3
Affiliations

Affiliations

  • 1 Postdoctoral Research Station, The First Affiliated Hospital of Wannan Medical College, Yijishan Hospital, No. 2 Zheshan Xi Road, Wuhu, 241001, Anhui Province, PR China; Postdoctoral Research Station, Medical Integration and Practice Center, Shandong University, No. 44 Wenhua Xi Road, Jinan, 250012, Shandong Province, PR China; Department of Trauma Orthopedics, The First Affiliated Hospital of Wannan Medical College, Yijishan Hospital, No. 2, Zheshan Xi Road, Wuhu, 241001, Anhui Province, PR China.
  • 2 Department of Trauma Orthopedics, The First Affiliated Hospital of Wannan Medical College, Yijishan Hospital, No. 2, Zheshan Xi Road, Wuhu, 241001, Anhui Province, PR China.
  • 3 Department of Trauma Orthopedics, The First Affiliated Hospital of Wannan Medical College, Yijishan Hospital, No. 2, Zheshan Xi Road, Wuhu, 241001, Anhui Province, PR China. Electronic address: pkuyang@hotmail.com.
PMID: 40947036 DOI: 10.1016/j.freeradbiomed.2025.09.023
Abstract

Background: Valproic acid (VPA), a histone deacetylase inhibitor, exhibits dose-dependent effects on bone homeostasis. This study investigates whether low-dose VPA protects against ovariectomy (OVX)-induced osteoporosis by targeting oxidative stress and Ferroptosis.

Methods: OVX rats received low- (100 mg/kg/d) or high-dose (300 mg/kg/d) VPA for 12 weeks. Bone microstructure was analyzed by micro-CT. Systemic redox status was evaluated by measuring MDA, SOD, GSH, and Fe2+. Ferroptosis markers (GPX4, ACSL4, FTH1, NCOA4) were examined. In MC3T3-E1 cells pretreated with VPA (0.5-3 mM), erastin was used to induce Ferroptosis. The EZH2/H3K27me3 pathway and osteoclastogenesis were further assessed.

Results: OVX induced bone loss, oxidative stress (elevated MDA/Fe2+, decreased SOD/GSH), and Ferroptosis activation (increased ACSL4/NCOA4, decreased GPX4/FTH1). Low-dose VPA reversed these changes, improved bone density and microarchitecture, and reduced bone resorption. High-dose VPA showed no protective effects. In vitro, 1 mM VPA attenuated erastin-induced lipid peroxidation, mitochondrial damage, and Ferroptosis. Mechanistically, VPA activated EZH2/H3K27me3 signaling, enhancing H3K27me3 enrichment at the NCOA4 promoter to suppress ferritinophagy and Ferroptosis. VPA also inhibited RANKL-induced osteoclast differentiation.

Conclusion: Low-dose VPA ameliorates osteoporosis by restoring redox homeostasis, epigenetically inhibiting NCOA4-mediated ferritinophagy via EZH2/H3K27me3 activation, and suppressing osteoclastogenesis. These findings identify low-dose VPA as a multifaceted anti-osteoporotic agent and highlight the EZH2/H3K27me3/NCOA4 axis as a pivotal regulatory pathway in bone redox biology.

Keywords

Ferritinophagy; Ferroptosis; Osteoporosis; Oxidative stress; Redox homeostasis; Valproic acid.

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