Fig. 3

Knockdown CAT-1 inhibits L-arginine uptake in RA FLSs. a Decreased protein expression of CAT-1 in RA FLSs transfected with CAT1-siRNA and cultured under normoxic or hypoxic conditions were detected by western blots. b The relative protein levels of CAT-1 in RA FLSs transfected with CAT1-siRNA were analyzed, and β-actin was used as the internal control. c Representative peak figures of L-arginine in the supernatant of RA FLSs transfected with CAT1-siRNA and cultured under normoxic or hypoxic conditions were detected by LC–MS/MS. d The concentration of L-arginine in the supernatant of RA FLSs transfected with CAT1-siRNA and cultured under normoxic or hypoxic conditions. The data are expressed as the mean ± SD of three independent experiments. *P < 0.05