背景:软骨代谢失调是膝骨关节炎(KOA)的关键驱动因素。调节稳态可以减轻KOA中的软骨退变。姜黄烯醇,来源于中药姜黄,已证明具有增强软骨细胞增殖和减少凋亡的潜力。然而,姜黄烯醇治疗KOA的具体机制尚不清楚.本研究从转录组学和代谢组学的角度探讨姜黄烯醇治疗KOA的分子机制,以及体内和体外实验验证。
方法:在本研究中,建立了内侧半月板(DMM)诱导的KOA小鼠模型。小鼠腹腔注射4和8mg/kg浓度的姜黄烯醇。使用Micro-CT评估姜黄烯醇对KOA软骨和软骨下的影响,组织病理学,免疫组织化学(IHC)。体外,用10μg/mL脂多糖(LPS)诱导OA软骨细胞,并用姜黄烯醇处理以评估其增殖。凋亡,通过CCK8测定和细胞外基质(ECM)代谢,流式细胞术,和软骨细胞染色。此外,转录组学和代谢组学用于鉴定差异表达基因(DEG)和代谢物。最后,整合多组学分析,虚拟分子对接(VMD),和分子动力学模拟(MDS),IHC,免疫荧光(IF),PCR,进行Westernblot(WB)验证以阐明姜黄烯醇改善KOA软骨变性的机制。
结果:姜黄烯醇改善了KOA小鼠的软骨破坏和软骨下骨丢失,促进软骨修复,上调COL2的表达,下调MMP3,改善ECM合成代谢。此外,姜黄烯醇还能减轻LPS对细胞增殖活性的损害,抑制细胞凋亡,促进ECM合成。转录组分析结合加权基因共表达网络分析(WGCNA)鉴定了KOA中19个关键基因的显著下调。代谢组学分析显示,姜黄烯醇下调d-丙氨酰-d-丙氨酸的表达,17a-雌二醇,谷胱甘肽,和琥珀酸,同时上调类固醇酸和壬二酸。整合的多组学分析表明,姜黄烯醇靶向KDM6B调节下游蛋白H3K27me3的表达,抑制组蛋白H3K27的甲基化,从而降低丁二酸水平并改善KOA软骨代谢稳态。最后,体内和体外研究结果表明,姜黄烯醇上调KDM6B,抑制H3K27me3表达,并刺激胶原蛋白II表达和ECM合成,从而维持软骨代谢稳态和减轻KOA软骨退变。
结论:姜黄烯醇通过上调KDM6B表达促进KOA软骨修复和改善软骨退变,从而减少H3K27甲基化和下调丁二酸,恢复代谢稳定性和ECM合成。
BACKGROUND: Cartilage metabolism dysregulation is a crucial driver in knee osteoarthritis (KOA). Modulating the homeostasis can mitigate the cartilage degeneration in KOA. Curcumenol, derived from traditional Chinese medicine Curcuma Longa L., has demonstrated potential in enhancing chondrocyte proliferation and reducing apoptosis. However, the specific mechanism of Curcumenol in treating KOA remains unclear. This study aimed to demonstrate the molecular mechanism of Curcumenol in treating KOA based on the transcriptomics and metabolomics, and both in vivo and in vitro experimental validations.
METHODS: In this study, a destabilization medial meniscus (DMM)-induced KOA mouse model was established. And the mice were intraperitoneally injected with Curcumenol at 4 and 8 mg/kg concentrations. The effects of Curcumenol on KOA cartilage and subchondral was evaluated using micro-CT, histopathology, and immunohistochemistry (IHC). In vitro, OA chondrocytes were induced with 10 μg/mL lipopolysaccharide (LPS) and treated with Curcumenol to evaluate the proliferation, apoptosis, and extracellular matrix (ECM) metabolism through CCK8 assay, flow cytometry, and chondrocyte staining. Furthermore, transcriptomics and metabolomics were utilized to identify differentially expressed genes (DEGs) and metabolites. Finally, integrating multi-omics analysis, virtual molecular docking (VMD), and molecular dynamics simulation (MDS), IHC, immunofluorescence (IF), PCR, and Western blot (WB) validation were conducted to elucidate the mechanism by which Curcumenol ameliorates KOA cartilage degeneration.
RESULTS: Curcumenol ameliorated cartilage destruction and subchondral bone loss in KOA mice, promoted cartilage repair, upregulated the expression of COL2 while downregulated MMP3, and improved ECM synthesis metabolism. Additionally, Curcumenol also alleviated the damage of LPS on the proliferation activity and suppressed apoptosis, promoted ECM synthesis. Transcriptomic analysis combined with weighted gene co-expression network analysis (WGCNA) identified a significant downregulation of 19 key genes in KOA. Metabolomic profiling showed that Curcumenol downregulates the expression of d-Alanyl-d-alanine, 17a-Estradiol, Glutathione, and Succinic acid, while upregulating Sterculic acid and Azelaic acid. The integrated multi-omics analysis suggested that Curcumenol targeted KDM6B to regulate downstream protein H3K27me3 expression, which inhibited methylation at the histone H3K27, consequently reducing Succinic acid levels and improving KOA cartilage metabolism homeostasis. Finally, both in vivo and in vitro findings indicated that Curcumenol upregulated KDM6B, suppressed H3K27me3 expression, and stimulated collagen II expression and ECM synthesis, thus maintaining cartilage metabolism homeostasis and alleviating KOA cartilage degeneration.
CONCLUSIONS: Curcumenol promotes cartilage repair and ameliorates cartilage degeneration in KOA by upregulating KDM6B expression, thereby reducing H3K27 methylation and downregulating Succinic Acid, restoring metabolic stability and ECM synthesis.