Figure 2

Effect of 800 µM methylglyoxal on gene expression. TNF-α stimulated HUVECS were exposed to 0 µM, 400 µM or 800 µM methylglyoxal (MGO) in the presence or absence of carnosine (CN, 20 mM) for 24 hours. Gene expression profiling was performed by microarray analysis. Displayed are the p-value distribution across all examined genes (A) and the corresponding volcano plot (B) for the comparison 0 µM MGO vs. 800 µM MGO. (A) The distribution of p-values across all examined genes indicates an excess of p-values < 0.05 as suggested by the shape of the histogram. The bars represent a specific number of genes (y-axis) sharing a corresponding p-value (x-axis). (B) Volcano plot with nominal p-values on the y-axis and fold change (FC) expressed as log₂ on the x-axis. After adjustment for multiple testing (p_adj < 0.05 horizontal line) a total of 2328 genes were found to be significantly affected by 800 µM MGO. After filtering for FC ≥ ±1.5 (Log₂ (FC) ≤ −0.5 or Log₂ (FC) ≥ 0.5 vertical lines) 855 transcripts (342 up-regulated and 513 down-regulated) were identified. ANOVA was performed to identify differential expressed genes. A false positive rate of α = 0.05 with false discovery correction was taken as the level of significance.