Aims: The pathogenesis of
osteoarthritis (OA) is characterized by oxidative stress (OS) and sustained
inflammation that are substantially associated with epigenetic DNA methylation alterations of osteogenic gene expression.
Diacerein as an
anthraquinone anti-OA drug exhibits multiple chondroprotective properties, but less clarified pharmacological actions. Since
anthraquinone contain an epigenetic modulating property, in this study we investigate whether the anti-OA functions of
diacerein involve DNA methylation modulation and
antioxidant signaling. Results: The OA mice incurred by destabilization of medial meniscus exhibited marked suppression of
peroxisome proliferator-activated receptor-gamma (PPARγ), a chondroprotective
transcription factor with anti-
inflammation and OS-balancing properties, aberrant upregulations of
DNA methyltransferase (DNMT)1/3a, and PPARγ promoter hypermethylation in knee joint cartilage.
Diacerein treatment mitigated the cartilage damage and significantly inhibited the DNMT1/3a upregulation, the PPARγ promoter hypermethylation, and the PPARγ loss, and it effectively corrected the adverse expression of
antioxidant enzymes and inflammatory
cytokines. In cultured chondrocytes,
diacerein reduced the interleukin-1β-induced PPARγ suppression and the abnormal expression of its downstream
antioxidant enzymes in a gain of DNMT and PPARγ inhibition-sensitive manner, and in PPARγ knockout mice, the anti-OA effects of
diacerein were significantly reduced. Innovation: Our work reveals a novel anti-OA pharmacological property of
diacerein and identifies the aberrant DNMT elevation and the resultant PPARγ suppression as an important epigenetic pathway that mediates
diacerein's anti-OA activities. Conclusion: DNA methylation aberration and the resultant PPARγ suppression contribute significantly to epigenetic OA pathogenesis, and targeting PPARγ suppression via DNA demethylation is an important component of
diacerein's anti-OA functions. Antioxid. Redox Signal. 37, 40-53.