Withaferin A alleviates inflammation and joint injury in arthritic rats via elevating microRNA-1297 to target karyopherin alpha2.

Withaferin A (WFA) is a natural compound separated from the medicinal plant Withania somnifera. As reported, it has the potential to safely cure rheumatoid arthritis (RA) in animal models. Nevertheless, the action mechanism of WFA in treating RA has not been completely illuminated. The study was to explore the action and mechanism of WFA on arthritic rats. First, a collagen-induced arthritis rat model was established. WFA administration alleviated inflammation and injury in arthritic rats. Subsequently, fibroblast synovial cells (FLS) of arthritic rats were separated and cell proliferation and apoptosis abilities were tested. It was found that WFA was available to repress FLS cell proliferation and accelerate apoptosis. MicroRNA-1297 was downregulated in RA patients. Clinical correlation analysis suggested that miR-1297 in the serum of RA patients was negatively associated with pro-inflammatory factors interleukin (IL)-6, IL-17, tumor necrosis factor (TNF)-α, and RA diagnostic indexes (RF, DAS28). In the meantime, miR-1297 had superior diagnostic value in differentiating RA patients from healthy people. Karyopherin α2 (KPNA2) was the downstream target of miR-1297, while miR-1297 negatively modulated KPNA2 expression. Importantly, WFA further restrained KPNA2 expression via elevating miR-1297 in functional rescue experiments, thereby treating inflammation and injury in arthritic rats and repressing FLS cell proliferation and activation. In short, WFA alleviated inflammation and joint damage in arthritic rats via elevating miR-1297 to target KPNA2.