Wogonin modulates macrophage polarization and inflammatory signaling through the LSD1-p65 axis to alleviate osteoarthritis

Abstract

Background: The study elucidates wogonin's therapeutic mechanisms in osteoarthritis (OA) induced by medial meniscus destabilization (DMM), focusing on macrophage polarization regulation, inflammatory signaling modulation, and cellular crosstalk within OA joints.

Methods: A DMM-induced OA mouse model received intra-articular injection of wogonin for 8 weeks. In vitro analyses utilized LPS-stimulated Raw264.7 macrophages, MC3T3-E1 osteoblasts, and primary chondrocytes. Comprehensive methodologies included immunohistochemistry, RNA-seq, CRISPR-edited macrophages, molecular docking, and Drug Affinity Responsive Target Stability assays. Key parameters analyzed encompassed macrophage polarization dynamics, cytokine profiles, apoptosis, autophagy, and chondrocyte migratory capacity. The mechanistic role of the LSD1-p65 axis was further validated using CRISPR-edited macrophages and the CCL2 inhibitor bindarit.

Results: Firstly, wogonin bound lysine-specific histone demethylase 1A (LSD1/KDM1A), suppressing LPS-induced M1 polarization, while increasing CD163+ M2 macrophages in OA joints. Mechanistically, wogonin disrupted LSD1-mediated NF-κB p65 demethylation, enhancing p65 methylation and inhibiting JNK/NF-κB activation. Third, it restored autophagy to degrade p65, reducing apoptosis in osteoblasts and chondrocytes. Notably, wogonin upregulated CCL2-dependent chondrocyte migration yet concurrently inhibited pro-inflammatory mediators (TNF-α, IκBα) independently of CCL2. In vivo, wogonin reduced serum IL-6, improved cartilage integrity, and stabilized subchondral bone. The CCL2 inhibitor bindarit attenuated IL-6/tenascin-C expression but preserved wogonin's anti-inflammatory efficacy, indicating pathway redundancy.

Conclusion: Wogonin alleviates OA pathology by targeting the LSD1-p65 axis to balance macrophage polarization and mitigate inflammatory cascades. Its dual modulation of immune responses and tissue repair highlights therapeutic potential, warranting validation in large animal models and human OA tissues for clinical translation. This work positions wogonin as a novel disease-modifying agent for OA.

Keywords: Chondrocyte; Inflammatory cytokine; Macrophage; Osteoarthritis; Osteoblast; Wogonin.