Cayratia albifolia C.L.Li exerts anti-rheumatoid arthritis effect by inhibiting macrophage activation and neutrophil extracellular traps (NETs)

Background: Cayratia albifolia C.L.Li (CAC), commonly known as "Jiao-Mei-Gu" in China, has been extensively utilized by the Dong minority for several millennia to effectively alleviate symptoms associated with autoimmune diseases. CAC Extract is believed to possess significant anti-inflammatory properties within the context of Dong medicine. However, an in-depth understanding of the specific pharmaceutical effects and underlying mechanisms through which CAC Extract acts against Rheumatoid Arthritis (RA) has yet to be established.

Methods: Twenty-four Sprague-Dawley rats were divided into four groups, with six rats in each group. To induce the collagen-induced Arthritis (CIA) model, the rats underwent a process of double immunization with Collagen and Adjuvant. CAC Extract (100 mg/kg) was orally administered to rats. The anti-RA effects were evaluated in CIA rats by Arthritis score, hind paw volume and histopathology analysis. Pull-down assay was conducted to identify the potential targets of CAC Extract from RAW264.7 macrophage lysates. Moreover, mechanism studies of CAC Extract were performed by immunofluorescence assays, Real-Time PCR and Western blot.

Results: CAC Extract was found to obviously down-regulate hind paw volume of CIA rats, with diminished inflammation response and damage. 177 targets were identified from CAC Extract by MS-based pull-down assay. Bioinformatics analysis found that these targets were mainly enriched in macrophage activation and neutrophils extracellular traps (NETs). Additionally, we reported that CAC Extract owned significant anti-inflammatory activity by regulating PI3K-Akt-mTOR signal pathway, and inhibited NETosis in response to PMA.

Conclusions: We clarified that CAC Extract significantly attenuated RA by inactivating macrophage and reducing NETosis via a multi-targets regulation.