Wogonin ameliorates osteoarthritis by targeting the STAT3/PIM1 axis to attenuate chondrocyte senescence.

Abstract

<p>BACKGROUND: Wogonin, a flavonoid component derived from Scutellaria baicalensis Georgi roots, exerts considerable therapeutic efficacy against osteoarthritis (OA), yet with unclear precise mechanism. PURPOSE: To investigate the therapeutic effect of Wogonin on OA and clarify its potential mechanisms. METHODS: IL-1β-induced C28/I2 cells and mice undergoing destabilization of the medial meniscus (DMM) were constructed to simulate OA. The curative effect of Wogonin was evaluated using pathological staining, micro-CT, Tunel, EdU and migration assay. The repair effect of Wogonin on cartilage injury was assessed by immunohistochemistry, immunofluorescence, toluidine blue and SA-β-gal. The interaction potency between Wogonin and its target protein was validated using RNA-Seq, molecular dynamics simulations (MDs), surface plasmon resonance (SPR), cellular thermal shift assay (CETSA) and drug affinity responsive target stability (DARTS). The mechanism by which Wogonin modulated OA was validated using STAT3 agonist and pcDNA3.1-STAT3. RESULTS: Wogonin could ameliorate articular cartilage injury, inhibit synovitis and osteophyte formation in DMM mice, promote the proliferation and hinder apoptosis of IL-1β-induced C28/I2 cells. Wogonin could suppress matrix degradation, stimulate matrix synthesis and proteoglycan secretion, enhance CDK and Cyclin transcriptional levels, concomitantly retarded SA-β-gal, senescence-associated secretory phenotype (SASP), γ-H2A.X, P16, P21 and P53. Mechanistically, STAT3 was a direct target of Wogonin. Upregulation of STAT led to significantly increased p-STAT3/STAT3 and PIM1 expression, and simultaneously aggravated cartilage injury and cell senescence. In contrast, Wogonin inhibited its activation by directly binding STAT3 and reversed the above pathological changes. CONCLUSION: Wogonin could inhibit chondrocyte senescence, reduce cartilage damage and alleviate OA by targeting the STAT3/PIM1 axis.</p>