Although Hif‐2α is a master regulator of catabolic factor expression in osteoarthritis development, Hif‐2α inhibitors remain undeveloped. The aim of this study was to determine whether Cirsium japonicum var. maackii (CJM) extract and one of its constituents, apigenin, could attenuate the Hif‐2α‐induced cartilage destruction implicated in osteoarthritis progression. In vitro and in vivo studies demonstrated that CJM reduced the IL‐1β‐, IL‐6, IL‐17‐ and TNF‐α‐induced up‐regulation of MMP3, MMP13, ADAMTS4, ADAMTS5 and COX‐2 and blocked osteoarthritis development in a destabilization of the medial meniscus mouse model. Activation of Hif‐2α, which directly up‐regulates MMP3, MMP13, ADAMTS4, IL‐6 and COX‐2 expression, is inhibited by CJM extract. Although cirsimarin, cirsimaritin and apigenin are components of CJM and can reduce inflammation, only apigenin effectively reduced Hif‐2α expression and inhibited Hif‐2α‐induced MMP3, MMP13, ADAMTS4, IL‐6 and COX‐2 expression in articular chondrocytes. IL‐1β induction of JNK phosphorylation and IκB degradation, representing a critical pathway for Hif‐2α expression, was completely blocked by apigenin in a concentration‐dependent manner. Collectively, these effects indicate that CJM and one of its most potent constituents, apigenin, can lead to the development of therapeutic agents for blocking osteoarthritis development as novel Hif‐2α inhibitors.
3′-Sialyllactose (3′-SL), a natural prebiotic, maintains immune homeostasis and exerts antiinflammatory and anti-arthritic effects. Although regulatory T cells (Tregs) prevent excessive inflammation and maintain immune tolerance, the effect of 3′-SL on Treg regulation is unclear. This study aimed to investigate the effect of 3′-SL on Treg responses in atopic dermatitis (AD) pathogenesis. Oral administration of 3′-SL reduced AD-like symptoms such as ear, epidermal, and dermal thickness in repeated topical application of house dust mites (HDM) and 2,4-dinitrochlorobenzene (DNCB). 3′-SL inhibited IgE, IL-1β, IL-6, and TNF-α secretion and markedly downregulated AD-related cytokines including IL-4, IL-5, IL-6, IL-13, IL-17, IFN-γ, TNF-α, and Tslp through regulation of NF-κB in ear tissue. Additionally, in vitro assessment of Treg differentiation revealed that 3′-SL directly induced TGF-βmediated Treg differentiation. Furthermore, 3′-SL administration also ameliorated sensitization and elicitation of AD pathogenesis by suppressing mast cell infiltration and production of IgE and proinflammatory cytokines in mouse serum by mediating the Treg response. Furthermore, Bifidobacterium population was also increased by 3′-SL administration as prebiotics. Our data collectively show that 3′-SL has therapeutic effects against AD progression by inducing Treg differentiation, downregulating AD-related cytokines, and increasing the Bifidobacterium population. Prebiotics are substances that improve the intestinal environment as a nutrient source for probiotics that help the growth of intestinal microbiota 1. Prebiotics are often composed of carbohydrates such as oligosaccharides, most of which are in the form of dietary fibre 2. Probiotics have a beneficial effect on the intestinal environment, prevent the growth of harmful bacteria in the intestine, improve immunity, ameliorate skin diseases such as atopic dermatitis (AD) and psoriasis, and inhibit metabolic syndrome 3. There are hundreds of beneficial bacteria that live in the intestine, but very few strains can be cultured outside the gut. Therefore, the only way to increase the number of desired strains without external supplementation is to use prebiotics. Notably, these beneficial microbiotas are known to be closely related to many autoimmune diseases such as AD.
Seomae mugwort, a Korean native variety of Artemisia argyi , exhibits physiological effects against various diseases. However, its effects on osteoarthritis (OA) are unclear. In this study, a Seomae mugwort extract prevented cartilage destruction in an OA mouse model. In vitro and ex vivo analyses revealed that the extract suppressed MMP3, MMP13, ADAMTS4 and ADAMTS5 expression induced by IL‐1β, IL‐6 and TNF‐α and inhibited the loss of extracellular sulphated proteoglycans. In vivo analysis revealed that oral administration of the extract suppressed DMM‐induced cartilage destruction. We identified jaceosidin in Seomae mugwort and showed that this compound decreased MMP3, MMP13, ADAMTS4 and ADAMTS5 expression levels, similar to the action of the Seomae mugwort extract in cultured chondrocytes. Interestingly, jaceosidin and eupatilin combined had similar effects to Seomae mugwort in the DMM‐induced OA model. Induction of IκB degradation by IL‐1β was blocked by the extract and jaceosidin, whereas JNK phosphorylation was only suppressed by the extract. These results suggest that the Seomae mugwort extract and jaceosidin can attenuate cartilage destruction by suppressing MMPs, ADAMTS4/5 and the nuclear factor‐κB signalling pathway by blocking IκB degradation. Thus, the findings support the potential application of Seomae mugwort, and particularly jaceosidin, as natural therapeutics for OA.
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