SPHK1 and rheumatoid arthritis: Furthermore, recent animal experiments have revealed that gardenia glycosides can inhibit the activation of the S1P/S1PR1 signaling pathway through SPHK1, leading to reduced expression of VEGF, inhibition of neoangiogenesis, diminished production of synovial tissue, alleviation of bone erosion, and effective alleviation of RA symptoms [105].