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Rheumatoid arthritis (RA) is a chronic autoimmune joint disease that causes cartilage and bone damage or even disability, seriously endangering human health. Chronic synovial inflammation has been shown to play a vital role in the disease sustainability. Therefore, down-regulation of synovial inflammation is considered to be an effective discipline for RA therapy. Polyene phosphatidylcholine (PPC) is a hepatoprotective agent, which was observed to inhibit inflammation in macrophages and prevent collagen-induced arthritis (CIA) of rats in our previous study. However, the underlying mechanism remains unclear. The present study further reported that PPC can inhibit the synovial inflammation. In lipopolysaccharide (LPS)-stimulated primary synovial fibroblasts (SFs) of mice, PPC significantly decreased pro-inflammatory cytokines production while increasing anti-inflammatory cytokines level. In this process, PPC down-regulated the expression of TLR-2 and their downstream signaling molecules such as MyD88, p-ERK1/2, p-JNK1/2, p-P38 in the MAPK pathway and p-IκBα and NF-κB-p65 in NF-kB pathway. Moreover, the inhibitory effect of PPC on the above molecules and cytokines was weakened after the use of TLR-2 agonist Pam3CSK4. However, PPC lost its anti-inflammatory effect and showed an activation of MAPK and NF-kB pathways in the TLR-2-/- primary SFs after exposure to LPS. Furthermore, these results were confirmed in the SFs from the CIA mouse ex vivo. Collectively, this study demonstrated that PPC can alleviate synovial inflammation through TLR-2 mediated MAPK and NF-κB pathways, which can be proposed to be a potential drug candidate for RA therapy.

Background Excretory-secretory products (ESPs) released by helminths are well-known to regulate T cell responses in the host. However, their direct influence in the differentiation of naïve T cells, and especially B cells, remains largely unknown. This study investigated the effects of Echinococcus granulosus protoscoleces ESPs (EgPSC-ESPs) on the differentiation of IL-10-producing B cells (B10), IL-17A-producing B cells (B17) and Th17 cells. Methods BALB/c mice injected with EgPSC were used to evaluate the in vivo profiles of B10, B17 and Th17 cells. In vitro purified CD19+ B and naïve CD4+ T cells were cultured in the presence of native, heat-inactivated or periodate-treated EgPSC-ESPs, and the differentiation of these cell subsets were compared. Results In contrast to the control group, infected mice showed higher frequencies of B10, B17 and Th17 cells, and higher levels of IL-10 and IL-17A in the sera. Interestingly, B17 cells were first identified to express CD19+CD1dhigh. In vitro, B cells cultured with native ESPs exhibited a higher percentage of B10 cells but lower percentage of B17 and Th17 cells compared to the PBS group. Moreover, the relative expression of IL-10 and IL-17A mRNA were consistent with the altered frequencies. However, ESPs subjected to heat-inactivation or periodate treatment exhibited an inverse effect on the induction of these cell subsets. Conclusions Our findings indicate that ESPs released by EgPSC can directly regulate the differentiation of B10, B17 and Th17 cells, which appear to be heat-labile and carbohydrate-dependent. Electronic supplementary material The online version of this article (doi:10.1186/s13071-017-2263-9) contains supplementary material, which is available to authorized users.