Fig 2: Cur suppresses AGEs/AGER axis-mediated ROS and ADSC apoptosis. (a) ADSCs pre-treated with AGEs were mixed with Cur or the p65 inhibitor PDTC (30 μM). Left: western blot demonstrates protein expression levels of AGER and phosphorylated and total p65. Right: comparison of AGER and p-p65 expression levels between the study groups. (b) ROS level was tested by fluorescence microscopy and total cell number was observed by bright field microscopy to calculate the percentage. (c) Flow cytometry showing ROS levels in ADSCs. (d) FITC/PI stained ADSCs analyzed by flow cytometry. Data are shown as means ± SD. Statistical analysis: *p<0.05, **p<0.01 and *p<0.001. AGE Advanced glycation end product, AGER AGE receptor, ROS reactive oxygen species, ADSC adipose-derived stem cell, Cur curcumin, PDTC pyrrolidinedithiocarbamate

Fig 3: Effects of the AGE/AGER axis on ROS production and ADSC apoptosis. (a) Left: western blot shows AGER expression after transfection with siAGER; siRNA served as a negative control for siAGER. Right: quantitative analysis comparing AGER expression levels between the groups. (b) ROS production was tested by fluorescence microscope and the total cell number was observed by bright field microscopy to calculate the percentage. (c) Flow cytometry showing ROS levels in ADSCs. (d) FITC/PI stained ADSCs analyzed by flow cytometry. Data are shown as means ± SD. Statistical analysis: *p<0.05, **p<0.01 and *p<0.05. AGE Advanced glycation end product, AGER AGE receptor, ADSC adipose-derived stem cell, ROS reactive oxygen species

Fig 4: Mechanisms of action of post-DM administration serum in PA-induced HepG2 cells. (A) Western blot images (n = 3 individual experiments) and their statistical analysis of protein expressions of RAGE and AKT1 in HepG2 cells. (B) Apoptosis in HepG2 cells exposed to PA. HepG2 cells were treated with either media alone (set as blank control), PA (250 μM), PA (250 μM) and serum saline (diluted to 2.5 %), or PA (250 μM) and serum DM (2.5 %). Intact cells, early apoptotic cells and late apoptotic or necrotic cells are located in the lower left, upper left and upper right quadrants of the cytograms, respectively; (C) Apoptotic cells were then calculated as the percentage of the sum of early and late apoptotic cells. (D) Western blot images (n = 3 individual experiments) and (E) their statistical analysis of relative protein expressions of p-mTOR/mTOR, p-AMPK/AMPK, LC3I/LC3II in PA-induced HepG2 cells. #p < 0.05, ##p < 0.01, ####p < 0.0001 vs. Con group, *p < 0.05, **p < 0.01, ****p < 0.0001 vs. Mod group as assessed by one-way ANOVA with Tukey's multiple comparison test. Con: control group; Mod: model group; DM: DM treatment group. Please refer to supplementary file 3 for original blot images in (A) and (D).

Fig 5: DM downregulated RAGE-AKT1 pathway and prevented early apoptosis in liver tissues of diabetic db/db mice. (A) Western blot images of the protein expressions of RAGE, AKT1 (n = 3 individual experiments); (B) Their statistical analysis in liver tissue. (C) Western blot images of the protein expressions of Bcl-2/Bax and caspase-3 (n = 3 individual experiments); (D) their statistical analysis in liver tissue. Con: control group; Mod: model group; DM: DM treatment group. #p < 0.05, ##p < 0.01, ###p<0.001 vs. Con group, *p < 0.05, **p<0.01 vs. Mod group as assessed by one-way ANOVA with Tukey's multiple comparison test. Please refer to supplementary file 1 for original blot images in (A) and (C).