Fig. 5

Effect of FFAR1 knockdown on mTOR and insulin signaling in INS-1 cells. Cells were transiently transfected with either 40 nM scrambled siRNA or FFAR1 siRNA for 48–72 h, harvested, and analyzed by qPCR. Duplicate cell repeats were performed for each group. Transfections yielded an efficiency of 75% (data not shown). a Around 60% FFAR1 knockdown was achieved on the mRNA level and led to a significant decrease in IRS-1 and an increase in INSR1β mRNA expression. Other targets of the mTOR and insulin signaling, such as PI3k, Raptor, Rictor, and S6K1, were not affected. GAPDH was used as a reference gene for normalization. b A representative Western blot of the protein expression and quantification is shown where approximately 30% FFAR1 knockdown was achieved that had a significant downregulatory effect on IRS-1 protein levels, but not on INSR1β. Values represent mean ± SEM and the data are representative of at least three independent experiments. *P < 0.05 and **P < 0.01