Thymoquinone inhibits TNF-α-induced inflammation and cell adhesion in rheumatoid arthritis synovial fibroblasts by ASK1 regulation.

Tumor necrosis factor-α (TNF-α) is a pro-inflammatory cytokine produced by monocytes/macrophage that plays a pathological role in rheumatoid arthritis (RA). In this study, we investigate the effect of thymoquinone (TQ), a phytochemical found in Nigella sativa, in regulating TNF-α-induced RA synovial fibroblast (RA-FLS) activation. Treatment with TQ (1-5μM) had no marked effect on the viability of human RA-FLS. Pre-treatment of TQ inhibited TNF-α-induced interleukin-6 (IL-6) and IL-8 production and ICAM-1, VCAM-1, and cadherin-11 (Cad-11) expression in RA-FLS (p<0.01). Evaluation of the signaling events showed that TQ inhibited TNF-α-induced phospho-p38 and phospho-JNK expression, but had no inhibitory effect on NF-κB pathway, in RA-FLS (p<0.05; n=4). Interestingly, we observed that selective down-regulation of TNF-α-induced phospho-p38 and phospho-JNK activation by TQ is elicited through inhibition of apoptosis-regulated signaling kinase 1 (ASK1). Furthermore, TNF-α selectively induced phosphorylation of ASK1 at Thr845 residue in RA-FLS, which was inhibited by TQ pretreatment in a dose dependent manner (p<0.01). Pre-treatment of RA-FLS with ASK1 inhibitor (TC ASK10), blocked TNF-α induced expression of ICAM-1, VCAM-1, and Cad-11. Our results suggest that TNF-α-induced ASK1-p38/JNK pathway is an important mediator of cytokine synthesis and enhanced expression of adhesion molecule in RA-FLS and TQ, by selectively inhibiting this pathway, may have a potential therapeutic value in regulating tissue destruction observed in RA.

Umar S ，Hedaya O ，Singh AK ，Ahmed S ... -  《-》

Anti-inflammatory activities of Chinese herbal medicine sinomenine and Liang Miao San on tumor necrosis factor-α-activated human fibroblast-like synoviocytes in rheumatoid arthritis.

Sinomenine, an alkaloid isolated from the root of Sinomenium acutum, has been used to alleviate the symptoms of rheumatic diseases. Liang Miao San (LMS), composed of the herbs Rhizoma Atractylodis (Cangzhu) and Cotex Phellodendri (Huangbai), is another traditional Chinese medicine formula for rheumatoid arthritis (RA) treatment. Although numerous studies have demonstrated the potential anti-inflammatory activities of sinomenine and LMS, the underlying intracellular mechanisms regulating the anti-inflammatory activities of sinomenine and LMS on human primary fibroblast-like synoviocytes (FLS) from RA patients and normal control subjects have not been elucidated. We investigated the in vitro anti-inflammatory activity of sinomenine and LMS on inflammatory cytokine tumor necrosis factor (TNF)-α-mediated activation of human normal and RA-FLS. The underlying intracellular signaling molecules were analyzed quantitatively using flow cytometry. Sinomenine was found to significantly inhibit TNF-α induced cell surface expression of vascular cell adhesion molecule (VCAM)-1 and release of inflammatory cytokine and chemokine IL-6, CCL2 and CXCL8 from both normal and RA-FLS (all p<0.05). Moreover, the suppression of sinomenine on TNF-α induced VCAM-1 expression and IL-6 release of RA-FLS was significantly higher than that of normal FLS (p<0.05). LMS significantly inhibited TNF-α-induced inflammatory chemokines CXCL10 and CCL5 release from both normal and RA-FLS, with significantly higher suppression on CXCL10 secretion in RA-FLS than that of normal FLS (all p<0.05). Further investigations showed that sinomenine and LMS could significantly suppress TNF-α-induced phosphorylation of inhibitor κBα and extracellular signal-regulated protein kinase, the central signaling molecules mediating TNF-α-induced VCAM-1 expression and chemokine production. Our results therefore provide a new insight into the differential anti-inflammatory activities of sinomenine and LMS through the suppression of TNF-α-activated FLS by modulating distinct intracellular signaling pathways in RA.

Chen DP ，Wong CK ，Leung PC ，Fung KP ，Lau CB ，Lau CP ，Li EK ，Tam LS ，Lam CW ... -  《-》

Resveratrol inhibits TNF-α-induced IL-1β, MMP-3 production in human rheumatoid arthritis fibroblast-like synoviocytes via modulation of PI3kinase/Akt pathway.

Tian J ，Chen JW ，Gao JS ，Li L ，Xie X ... -  《-》

Gastrodia elata attenuates inflammatory response by inhibiting the NF-κB pathway in rheumatoid arthritis fibroblast-like synoviocytes.

Gastrodia elata (GE), which belongs to the Orchidaceae family, was found to possess anti-inflammatory activity. However, the effect of GE on inflammatory response in rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS) remains largely unknown. Thus, the aim of this study was to investigate the effects of GE on tumor necrosis factor-α (TNF-α)-induced inflammatory response in RA-FLS and the underlying molecular mechanism was also explored. Our results demonstrated that GE significantly attenuated TNF-α-induced IL-6 and IL-8 production in RA-FLS. GE also inhibited TNF-α-induced MMP-3 and MMP-13 expression in RA-FLS. Furthermore, pretreatment with GE significantly attenuated TNF-α-induced the expression of p-p65 and IκBα degradation in RA-FLS. In conclusion, this study demonstrated for the first time that GE attenuated inflammatory response by inhibiting the NF-κB pathway signaling in RA-FLS. Thus, GE might have a therapeutic potential towards the treatment of RA.

Li Y ，Wang LM ，Xu JZ ，Tian K ，Gu CX ，Li ZF ... -  《-》

Anti-malarial agent artesunate inhibits TNF-alpha-induced production of proinflammatory cytokines via inhibition of NF-kappaB and PI3 kinase/Akt signal pathway in human rheumatoid arthritis fibroblast-like synoviocytes.

Xu H ，He Y ，Yang X ，Liang L ，Zhan Z ，Ye Y ，Yang X ，Lian F ，Sun L ... -  《RHEUMATOLOGY》