Franny Jongbloed

31 2 FASTING PROTECTS AGED-OVERWEIGHT MICE Biosynthesis , NRF2-mediated Oxidative Stress Response and LXR/RXR Activation . Amongst the top 15 regulated pathways, six pathways are represented in both aged and young mice (Table 1), demonstrating the similarity of the individual pathway results. The overlapping probe sets in both young and aged mice presumably contain those in the kidney that contribute to resistance to IRI. Therefore, the pathway overrepresentation was repeated for the 601 probe sets significantly expressed in both age groups (Table 2). The top overrepresented pathways involve RXR Activation , Fatty Acid β-oxidation or NRF2- mediated stress response , partly overlapping with the age group specific pathway analyses. (A) (B) Figure 5. Venn diagram and scatterplot of microarray data after fasting in young and aged mice. (A) Venn diagram of the significantly differentially up- and downregulated (FDR ≤ 5%, FC ≥ 1.5) and overlapping probe sets in kidneys of three days fasted aged and young mice in comparison with normal fed control mice. (B) Scatter plot comparing up- and downregulated trends and their fold ratios of probe sets significantly regulated (FDR ≤ 5%) in young-lean (red), aged-overweight mice (black) or overlapping in both groups (green). Without fold change cut-off, 85% of the genes showed the same directionality in both age groups. The grey solid line represents the reference diagonal (ratio young = ratio aged); the grey dotted lines show the 1.5-fold change cutoffs applied in 5A. Because of their relatively high fold change and their involvement in processes regulated by fasting found in the analysis, Pparα , Gst2 , Cyp4a14 and Sc4mol were validated by qRT-PCR.