Importance of immune response and metabolism in human aging

TCGA is the cancer database which is useful for aging research. We planned to study renal aging in view of system biology. After extracting normal samples of human kidney from TCGA database, differentially expressed genes (DEGs) were calculated. And gene set enrichment analysis (GSEA) and network analysis were carried out using protein-protein interaction (PPI) and TRANSFAC, database on transcription factors for the study. In the result of GSEA, the upregulated DEGs in old kidneys were related to pathways of immunology and inflammation while downregulated DEGs were associated with pathways involved in metabolism. In addition, the result of network analysis with TRANSFAC database showed that transcription factors such as NF-kappaBs, RELB and STATs interacted with upregulated DEGs in renal aging, and downregulated DEGs were associated with the transcription factors which control metabolism, like PPARs. Furthermore, according to the PPI, there were several genes which could be candidate hub genes of the network. Especially, UGT1A10, IVL, and KRT1 were worth conducting as a further study because of its high betweenness centrality in the network. In conclusion, this study suggests that increased inflammation and decline of metabolism through JAK/STAT, NF-kappaB, and PPAR signaling pathway lead to renal aging.