The relationship between TLR4 and inflammation-related diseases has been paid more and more attention. The studies have shown that TLR4/NF-κB signaling pathway plays an important role in the transmission of inflammatory signals. A large number of pro-inflammatory factors, chemokines, adhesion factors, TLR4 and its ligands interact with each other, and jointly promote the development of diseases. In this work, 8 target compounds were synthesized to screen the inhibitory activity of TLR4 in vitro. The results of TLR4 inhibition test in vitro showed that the double-ring conjugated enones had a good inhibitory activity, and the IC50 value of compound 4f was 0.56 ± 0.10 μM, and it was superior to the positive control methotrexate. To further study the anti-inflammatory effect and mechanism of double-ring conjugated enones by using LPS induced rat synovial cell inflammation model. The results of the mechanism test showed that compound 4f could effectively promote the apoptosis of rat synovial cells, and the mechanism might be related to the up-regulation of the expression of apoptosis-related protein Caspase-3. In addition, compound 4f could significantly inhibit the increase of inflammatory factors TNF-α, IL-1β and IL-6 in rat synovial cells induced by LPS, showing a good anti-inflammatory activity. In the TLR4/NF-κB signaling pathway test of rat synovial cells, compound 4f can effectively regulate the expression levels of TLR4, MyD88, NF-κB and IκB related proteins in TLR4/NF-κB signaling pathway, which may be due to its inhibition of LPS-induced inflammation in rat synovial cells. At the same time, it inhibits the abnormal proliferation of cells and its important mechanism promoted of apoptosis.
Keywords: Mechanism; Rheumatoid arthritis; Signaling pathway; TLR4/NF-κB.
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