[Mechanism of Huangqin Qingre Chubi Capsules in improving rheumatoid arthritis based on METTL3-SFRP4/Wnt/β-catenin...

The effect and mechanism of Huangqin Qingre Chubi Capsules(HQC) on rheumatoid arthritis(RA) were studied.Seventy male SPF rats were randomly divided into normal group, model group, low-(0. 18 g·kg~(-1)), middle-(0. 36 g·kg~(-1)), and high-(0. 72 g·kg~(-1)) dose groups of HQC, methotrexate group(MTX, 0. 75 mg·kg~(-1)), and negative control group(NC group, model +saline). Adjuvant arthritis fibroblast-like synoviocytes(AA-FLS) were divided into normal group, model group, low-, middle-, and high-dose groups of HQC, and negative control group. RT-qPCR and Western blot were used to detect the m RNA and protein expressions of METTL3, SFRP4, β-catenin, CCND1, c-Myc, MMP3, and fibronectin. The protein expression of MMP3 and β-catenin was detected by immunofluorescence. The gene expression level of METTL3 on AA-FLS was knocked down to further examine the expression of each gene. ELISA measured the levels of IL-1β, IL-6, and IL-8. The results showed that compared with the normal group, rats in the model group found redness and swelling in their limbs and significantly increased joint swelling. Compared with the model group, the joint swelling degree of each treatment group significantly decreased(P<0. 05). The paw retraction threshold and body weight mass index both significantly increased(P<0. 05). METTL3 was highly expressed on AA and negatively correlated with the expression of SFRP4. After treatment, the m RNA and protein expression of METTL3, β-catenin, CCND1, c-Myc, fibronectin, and MMP3 were significantly decreased on AA-FLS(P< 0. 05). Compared with the model group, knocking down METTL3 resulted in reduced m RNA and protein expression of β-catenin, CCND1, c-Myc, fibronectin, and MMP3(P< 0. 05). At the same time, the m RNA and protein expressions of β-catenin, CCND1, c-Myc, fibronectin, and MMP3 in the HQC+METTL3 knockdown group were significantly lower than those in the METTL3 knockdown group(P<0. 05). HQC could reduce the levels of IL-1β, IL-6, and IL-8 to varying degrees(P<0. 05). The results indicate that HQC has a significant improvement effect on arthritis in AA rats. The expression of METTL3 is significantly increased in synovial tissue and AA-FLS of AA rats, which may be a potential target for the diagnosis and treatment of RA. HQC improves RA through the METTL3-SFRP4/Wnt/β-catenin signaling pathway and has significant antiinflammatory and anti-rheumatic effects.