Figure 4: The effect of DPP4 inhibition on TGFβ and psmad2 expression (a) DPP4 inhibition with linagliptin (30 nM) did not reduce 30 mM high glucose induced total TGFβ secretion. HK2 cells were treated with high glucose (30 mM) and linagliptin (30 nM) for 48 h. Supernatant was collected and total TGFB was determined using ELISA. N=4, *p<0.05 vs. ctrl. (b) DPP4 inhibition with linagliptin (30 nM) reduced 30 mM high glucose induced active TGFβ secretion. HK2 cells were treated with high glucose (30 mM) and linagliptin (30 nM) for 48 h. Supernatant was collected and total TGFB was determined using ELISA. N=3, *p<0.05 vs. ctrl and † p<0.05 vs. 30 mM Glu. (c) DPP4 inhibition with linagliptin (30 nM) reduced 30 mM high glucose induced psmad2 expression. HK2 cells were treated with high glucose (30 mM) and linagliptin (30 nM) for 48 h. Cell lysate was collected and psmad2 expression corrected for actin was determined using western blot. N=4, *p<0.05 vs. ctrl and † p<0.05 vs. 30 mM Glu.