Andrographolide sulfonate alleviates rheumatoid arthritis by inhibiting glycolysis-mediated activation of PI3K/AKT to restrain Th17 differentiation

Andrographolide sulfonate (AS) is a sulfonated derivative of andrographolide extracted from Andrographis paniculata (Burm.f.) Nees, and has been approved for several decades in China. The present study aimed to investigate the novel therapeutic application and possible mechanisms of AS in the treatment of rheumatoid arthritis. Results indicated that administration of AS by injection or gavage significantly reduced the paw swelling, improved body weights, and attenuated pathological changes in joints of rats with adjuvant-induced arthritis. In addition, TNF-α, IL-6, IL-1β levels in the serum and ankle joints were lowered, and the possible relationship between AS and Th17 cells under arthritis condition was suggested by means of bioinformatics analysis as well as determination of spleen index as well as IL-17 and IL-10 levels. In vitro, AS was shown to block Th17 differentiation evidenced by the reduced percentages of CD4 ⁺ IL-17A ⁺ T cells and levels of RORγt, IL-17A, IL-17F, IL-21 and IL-22, without affecting the cell viability and apoptosis. The mechanisms were ascribed to the limited glycolysis as indicated by metabolomics analysis, glucose uptake and pH determination. To go deeper, AS might bind to HK2 to down-regulate the protein levels of HK2 but not GAPDH or PKM2, and overexpression of HK2 reversed the inhibition of AS on Th17 differentiation. Furthermore, AS impaired the activation of PI3K/AKT signals in vivo and in vitro, and which was abolished by addition of lactate. In conclusion, AS significantly improved AIA in rats by inhibiting glycolysis-mediated activation of PI3K/AKT to restrain Th17 differentiation.