Guizhi Shaoyao Zhimu decoction inhibits neutrophil extracellular traps formation to relieve rheumatoid arthritis via gut microbial outer membrane vesicles.

BACKGROUND

Rheumatoid arthritis (RA) is a common autoimmune disease with a high disability rate. Accumulating studies suggest that neutrophil extracellular traps (NETs) play a crucial role in the pathogenesis of RA and targeting NETs has emerged as a potential therapeutic strategy for RA. As a traditional Chinese medicine, Guizhi-Shaoyao-Zhimu Decoction (GSZD) has exhibited good efficacy in the treatment of rheumatoid arthritis (RA), while the underly mechanism especially the possibility that GSZD alter NETs formation to relieve RA remains unknown.

PURPOSE

Our study aimed to investigate relationship between GSZD and NETs in RA treatment and revealed underlying mechanism.

METHODS

We constructed collagen-induced arthritis (CIA) model and treated CIA mice with GZSY to validate therapeutic effects of GSZD and examine whether GZSD could inhibit NETs formation in RA. And 16S rRNA sequencing and Fecal microbiota transplantation (FMT) experiment were performed to determine whether GSZD could reduce NETs formation to alleviate RA in gut microbiota-associated manner and identify crucial bacterium in response to GSZD administration. CIA mice treated with effective bacteria and its outer membrane vesicles (OMVs) with oral administration to investigate protective effect against RA and NETs regulative efficiency. We utilized small interfering RNA in vivo and vitro to silence gene mediating effect of GZSD-gut microbiota-NETs.

RESULTS

GSZD could inhibit NETs formation and relive arthritis in CIA mice. Additionally, GSZD alter gut microbiota composition and significantly increase intestinal Parabacteroides goldsteinii (P.goldsteinii) abundance. Mechanistically, P.goldsteinii enriched by GSZD secreted outer membrane vesicles (OMVs) to translocate into joints and activate Cav-1-Nrf2 axis, leading to reduced NETs formation and alleviate arthritis. In clinical, the abundance of P.goldsteinii exhibited negative correlation with NETs indexes and RA disease activities.

CONCLUSION

Our findings suggest that GSZD inhibits NETs formation to relieve RA in P.goldsteinii-Cav-1-Nrf2 associated manner, which could provide new sight of the prevention and treatment of RA.