[Xinfeng Capsules promotes apoptosis of synovial fibroblasts and attenuates inflammation in rheumatoid arthritis by regulating lncRNA MAPKAPK5-AS1].

To explore the regulatory effects of Xinfeng Capsules(XFC) on the apoptosis of synovial fibroblasts(FLS) and inflammation in rheumatoid arthritis(RA) via lncRNA MAPKAPK5-AS1(MK5-AS1). Thirty healthy people and 30 patients with RA due to spleen deficiency and dampness exuberance were collected for extracting the peripheral blood mononuclear cells(PBMCs) before and after XFC treatment, which were used to observe the correlation between MK5-AS1 and clinical indicators as well as MK5-AS1 expression before and after XFC treatment. Following the establishment of RA-FLS cell line and the preparation of XFC-containing serum, MK5-AS1-overexpression plasmid was constructed and transfected into RA-FLS for investigating the efficacy of XFC-containing serum in regulating inflammation and apoptosis of RA-FLS via MK5-AS1. The expression of MK5-AS1 in PBMCs of patients with RA due to spleen deficiency and dampness exuberance was decreased(P<0.001). The ROC curve analysis revealed the AUC of 83.9%. Correlation analysis showed that MK5-AS1 was negatively correlated with ESR, CRP, RF, CCP, and spleen deficiency and dampness exuberance syndrome score. The expression of MK5-AS1 increased significantly after XFC treatment(P<0.001). As demonstrated by association analysis, XFC decreased MK5-AS1, ESR, CRP, RF, and spleen deficiency and dampness exuberance syndrome score, with the degree of support all greater than 83%, confidence greater than 80%, and lift greater than 1. The results of RT-qPCR showed that the MK5-AS1 RNA expression significantly decreased after TNF-α stimulation(P<0.01), which, however, increased significantly after the intervention with XFC-containing serum(P<0.05). Such expression rose again after the transfection of pcDNA3.1-MK5-AS1(P<0.01). ELISA results showed that TNF-α stimulation elevated the expression of pro-inflammatory factor IL-17 but lowered the expression of anti-inflammatory factor IL-4(P<0.01). After intervention with XFC-containing serum, the expression of IL-17 decreased while that of IL-4 increased(P<0.01). The transfection of pcDNA3.1-MK5-AS1 contributed to the reduction in IL-17 expression but the elevation in IL-4 expression(P<0.01). The immunofluorescence(IF) findings demonstrated that the expression of pro-apoptotic protein Bax was down-regulated, whereas that of the anti-apoptotic protein Bcl-2 was up-regulated after TNF-α stimulation(P<0.01). After the intervention with XFC-containing serum, the Bax expression was increased, while Bcl-2 expression was decreased(P<0.01), which were remarkably collaborated by the transfection of pcDNA3.1-MK5-AS1(P<0.05). The expression of MK5-AS1 is significantly decreased in both RA-PBMCs and RA-FLS, implying that XFC inhibits inflammatory reaction and promotes the apoptosis in RA by regulating the expression of MK5-AS1.