CUL4B promotes the pathology of adjuvant-induced arthritis in rats through the canonical Wnt signaling.

This work aims to discuss the possibility that disordered CUL4B was involved in the pathogenesis of adjuvant-induced arthritis (AIA) in rats. Synovium and FLS from AIA rats both showed increased CUL4B and β-catenin, and up-regulated CUL4B enhanced the canonical Wnt signaling by targeting the GSK3β. Increased CUL4B promoted the FLS abnormal proliferation, activated the secretion of IL-1β and IL-8, and promoted the production of AIA pathology gene MMP3 and fibronectin. Furthermore, miR-101-3p was significantly down-regulated in AIA rats compared with controls, and transfection of AIA FLS with miR-101-3p mimics significantly down-regulated the CUL4B expression, whereas transfection with miR-101-3p inhibitors resulted in an opposite observation. The dual-luciferase reporter assay confirmed that the CUL4B was a direct target of miR-101-3p, and further analysis suggested that lowly expressed miR-101-3p contributed to disordered CUL4B activating the canonical Wnt signaling pathway and further promoting the development of AIA rats. Thus clarification of the CUL4B roles in the pathogenesis of AIA rats and corresponding mechanisms will contribute to the disease diagnosis and treatment for rheumatoid arthritis (RA) patients. KEY MESSAGES: CUL4B expression is up-regulated in synovium and FLS from AIA rats. Increased CUL4B promotes the canonical Wnt signaling. Increased CUL4B promotes the pathogenesis of AIA rats. Decreased miR-101-3p contributes to disordered CUL4B.