Sinomenine inhibits fibroblast-like synoviocyte proliferation by regulating α7nAChR expression via ERK/Egr-1 pathway.

Fibroblast like synoviocyte (FLS) is a crucial in the pathogenesis of rheumatoid arthritis (RA), and involved in inflammation and joint destruction. Sinomenine (SIN), an alkaloid derived from the plant Sinomenium acutum, has anti-inflammatory and analgesic effect and been used for RA treatment in China. Alpha 7 nicotinic acetylcholine receptors (α7nAChR), as the key receptor in cholinergic anti-inflammatory pathway (CAP) to inhibit inflammation, has been detected in RA patients synovium, but its role is still unclear. Here we investigated the association between the aggressive proliferation of FLS and α7nAChR expression and the effect of sinomenine. FLS was isolated from synovial tissues of adjuvant-induced-arthritis (AIA) rat. Tumor necrosis factor(TNF)-α was used to induce the aggressive proliferation of FLS. MTT assay was applied to evaluate the proliferation of FLS. The messenger RNA (mRNA) and protein levels of α7nAChR and early growth response gene-1 (Egr-1) were measured. The results showed that TNF-α induced FLS proliferation in vitro (P < .01) and increased the phosphorylation of ERK1/2 and the expression of Egr-1 and α7nAChR (P < .05 or P < .01). U0126, the inhibitor of ERK1/2 inhibited α7nAChR expression and FLS proliferation significantly (P < .05 or P < .01). Specific short interference RNA(siRNA) of α7nAChR decreased α7nAChR expression and inhibited FLS proliferation as well. SIN inhibited the proliferation of FLS and decreased the phosphorylation of ERK1/2, and the expression of Egr-1 and α7nAChR induced by TNF-α (P < .05). In conclusion, the expression of α7nAChR involved in the aggressive proliferation of FLS induced by TNF-α and was regulated by ERK/Egr-1 signal pathway. SIN inhibited FLS proliferation and α7nAChR expression through inhibiting ERK/Egr-1 signal pathway, this may contribute to the anti-inflammatory and anti-arthritic effect of SIN.

The sinomenine enteric-coated microspheres suppressed the TLR/NF-κB signaling in DSS-induced experimental colitis.

Sinomenine is a pure alkaloid with immunosuppressive effects that is extracted from the Chinese medicinal plant Sinomenium acutum. We studied the therapeutic effects of sinomenine on inflammatory bowel disease. In this study, we randomly divided mice into the following ten groups: Control group; DSS-induced colitis group; Salicylazosulfapyridine (SASP)-treated group; Chitosan-treated group; low-, medium-, and high-dose sinomenine-treated and sinomenine enteric-coated microspheres-treated groups. We recorded changes in colon length, disease activity index (DAI), and colon pathology, measured TLR4, MyD88, SIGIRR, NF-κB p65 protein levels and inflammatory serum cytokine levels. Except for the Control group, the weight of mice in each group decreased, the DAI of the DSS-induced colitis group was significantly higher than the other groups, and the DAIs of the sinomenine- and sinomenine enteric-coated microspheres-treated groups were significantly lower than that of the SASP-treated group. TLR4, MyD88, NF-κB p65 and proinflammatory cytokine expressions decreased dose dependently in the sinomenine and sinomenine enteric-coated microspheres-treated groups and were generally lower in the sinomenine enteric-coated microspheres groups. However, SIGIRR and anti-inflammatory IL-10 expressions exhibited the opposite pattern. Based on the superior therapeutic effect, sinomenine enteric-coated microspheres might regulate TLR/NF-κB signaling and would be beneficial for an effective and safe therapy of inflammatory bowel disease.

Sinomenine potentiates degranulation of RBL-2H3 basophils via up-regulation of phospholipase A2 phosphorylation by Annexin A1 cleavage and ERK phosphorylation without influencing on calcium mobilization.

Sinomenine (SIN), an alkaloid derived from the Chinese medicinal plant Sinomenium acutum, is the major component of Zhengqing Fongtong Ning (ZQFTN), a pharmaceutical drug produced by Hunan Zhengqing Pharmaceutical Co. Ltd. in China for the treatment of rheumatoid arthritis and other autoimmune diseases. Some clinic reports indicate that ZQFTN may induce an anaphylactic reaction via potentiating the degranulation of immune cells. In the current study, we aimed to examine whether SIN is capable of inducing the degranulation of basophilic leukemia 2H3 (RBL-2H3) cells to elucidate how the anaphylactic reaction occurs. The results revealed that SIN could up-regulate ß-hexosaminidase levels in RBL-2H3 cells without significant cytotoxicity, suggesting that SIN could induce the degranulation of RBL-2H3 cells. Furthermore, SIN increased the release of prostaglandin D2 (PGD2) and prostaglandin E2 (PGE2) in RBL-2H3 cells via promoting the expression of phosphorylated-extracellular signal-regulated kinase (P-ERK), the cleavage of Annexin A1 (ANXA1), and phosphorylated-cytosolic phospholipase A2 (P-cPLA2), as well as cyclooxygenase-2 (COX-2). The ERK inhibitor, PD98059, significantly attenuated the up-regulatory effect of SIN on cPLA2 phosphorylation. Interestingly, SIN did not significantly increase Ca(2+) influx in the cells. These findings not only explored the anaphylactic reaction and underlying mechanism of ZQFTN in RBL-2H3 cells, but may promote the development of relevant strategies for overcoming the adverse effects of the drug.