Panlongqi Tablet (PLQT) Inhibits LPS-Induced Abnormal Proliferation of RA-HFLS by Regulating PI3K/ AKT and MAPK Signaling Pathways

Panlongqi Tablet (PLQT), a traditional Chinese formula, is effective in the clinical treatment of Rheumatoid Arthritis (RA) in China for several decades. However, the underlying mechanism of PLQT’s therapeutic effect remains unclear. The main chemical constituents of PLQT were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The human fibroblast-like synovial cells in rheumatoid arthritis (RA-HFLS) were stimulated with LPS (10 μg/mL) to establish a inflammatory model in vitro. The cells were then treated with PLQT-medicated serum to verify the protective effect of the herbal compound. MTT assay was used to detect the viability of RAHFLS and abnormal cell proliferation. The inflammatory factors levels including interleukin-1β (IL-1β), interleukin-6 (IL-6), and interleukin-17 (IL-17) in RAHFLS were measured by ELISA. In addition, the cell cycle progression was analyzed by flow cytometry and protein expression of Proliferating Cell Nuclear Antigen (PCNA) was detected using immunohistochemistry and western blot. The protein expression levels associated with PI3K/AKT and MAPK signaling pathways in RA-HFLS were detected by western blot analyses. Our results revealed that PLQT treatment effectively inhibited the abnormal proliferation of RA-HFLS and decreased the inflammatory factors levels. The proportion of cells in S phase was significantly increased with the treatment of PLQT. Meanwhile, the expression levels of PCNA, p-PI3K, p-AKT, p-mTOR, p-JNK/JNK, p-ERK/ ERK, and p-P38/P38 proteins from RA-HFLS were dramatically inhibited by PLQT treatment. PLQT inhibits LPS-induced abnormal proliferation of RAHFLS, which may be related to the down regulation of PCNA, and the inhibition of abnormally activated PI3K/AKT and MAPK signaling pathways.