Geniposide downregulates the VEGF/SphK1/S1P pathway and alleviates angiogenesis in rheumatoid arthritis in vivo and in vitro.

The VEGF/SphK1/S1P pathway is closely related to angiogenesis in rheumatoid arthritis (RA), but the precise underlying mechanisms are unclear at present. Here, we explored the involvement of the VEGF/SphK1/S1P cascade in RA models and determined the effects of GE intervention. Our results showed abnormal expression of proteins related to this pathway in RA synovial tissue. Treatment with GE effectively regulated the signal axis, inhibited angiogenesis, and alleviated RA symptoms. In vitro, TNF-ɑ enhanced the VEGF/SphK1/S1P pathway in a co-culture model of fibroblast-like synoviocytes (FLS) and vascular endothelial cells (VEC). GE induced downregulation of VEGF in FLS, restored the dynamic balance of pro-/antiangiogenic factors, and suppressed SphK1/S1P signaling in VEC, resulting in lower proliferation activity, migration ability, tube formation ability, and S1P secretion ability of VEC cells. Additionally, SphK1-specific small interfering RNA (siRNA) blocked the VEGF/SphK1/S1P cascade, which can effectively alleviate the stimulatory effect of FLS on VEC and further enhanced the therapeutic effect of GE. Taken together, our results demonstrate that GE suppresses the VEGF/SphK1/S1P pathway and alleviates the stimulation of VEC by FLS, thereby preventing angiogenesis and promoting therapeutic effects against RA.

Novel anti-inflammatory target of geniposide: Inhibiting Itgß1/Ras-Erk1/2 signal pathway via the miRNA-124a in rheumatoid arthritis synovial fibroblasts.

Geniposide (GE) is an active component isolated from the fruit of Gardenia jasminoides Ellis that has anti-inflammatory and other pharmacological effects; however, the underlying mechanism of GE action has not been elucidated in rheumatoid arthritis (RA). Previous studies have shown that GE plays a therapeutic role in RA via regulation of the integrin beta 1 (Itgß1)-mediated Ras-Erk1/2 signalling pathway. However, the specific mechanism of GE action on Itgß1 has not been clarified. Recent evidence indicates that microRNAs (miRNAs) are involved in the development of RA. In this study, we developed a miRNA-124a-based synoviocyte repair strategy. We demonstrated that miRNA-124a can directly inhibit the expression of the Itgß1 gene and decrease TNF-α-stimulated cell proliferation in vitro. MH7A cells were obtained from the patient with RA and treated with GE in the presence of TNF-α (10 ng/mL). Additionally, we demonstrated that the expression of miRNA-124a can be regulated by GE. GE upregulated the expression of miRNA-124a and decreased the expression of Itgß1 at the mRNA and protein levels. The results of the present study are the first to suggest that GE inhibits TNF-α-stimulated cell proliferation and blocks the activation of the Ras-Erk1/2 pathway via the upregulation of miRNA-124a expression. Our study elucidates the role of miRNA-124a as a protected miRNA in RA and may provide a novel strategy for the diagnosis and treatment of RA in the future.