Exploring and characterizing a novel combination of paeoniflorin and talatizidine for the treatment of rheumatoid arthritis

Wutou Decoction (WTD) achieves favorable therapeutic response in treating rheumatoid arthritis (RA), especially for wind-cold-dampness stimulating RA. However, its material basis and molecular mechanisms remain unclear. To address this problem, the main bioactive compounds (BACs) of WTD against RA and the candidate targets were identified in the current study via transcriptional regulatory network analysis, computational structure-based methods, as well as in vivo and in vitro experimental validations. As a result, we successfully established a RA rat model named AIA-S, which simulated the clinical manifestations and pathological changes of wind-cold-dampness stimulating RA, and also displayed the distinctive characteristics and biological basis of inflammatory-immune system imbalance and abnormal energy metabolism changes. In addition, ALOX15B-PPAR-γ-PTGS2-FGF2-IL-1β-c-JUN-MMP13-TGF-β1 signal axis, involved into thermogenesis and energy metabolism, as well as maintaining the balance of inflammation-immune system, was identified as a candidate target of WTD against RA, according to the transcriptional regulatory network analysis on "RA-related gene-WTD-effective gene interaction network". Moreover, Paeoniflorin (PAE) and Talatizidine (TLT) were demonstrated to be the main BACs of WTD against RA for the following reasons: firstly, both PAE and TLT were the BACs of WTD according to ADME analysis in silico and the pharmacokinetics analysis in vivo. Secondly, both PAE and TLT were able to bind with PPAR-γ, c-JUN, MMP13 and TGF-β1, which were the candidate targets of WTD against RA, with the strong binding affinity. Thirdly, the PAE and TLT combination exerted significant therapeutic effects on AIA-S rats through reversing the imbalance of inflammatory-immune system, and the disturbance of thermogenesis and energy metabolism, which were similar to WTD. More importantly, the administration of TLT or PAE alone didn't exert as prominently therapeutic effects as that of the two-BAC-combination did. Fourthly, the PAE and TLT combination promoted adipogenesis and lipogenesis by upregulating the PPAR-γ-induced lipogenic proteins. In conclusion, this study identified PAE and TLT as the main BACs of WTD in alleviating the severity of RA, and also developed a novel combination of PAE and TLT as a promising candidate drug for RA therapy.