Figure 5. Genes associated with cell proliferation are the genes most affected by SIRT6 knockdown in endothelial cells. HUVECs were transfected with 25 nM of control or SIRT6 siRNA. After 3 d, total RNA was isolated, and the gene expression profile was assessed with the Illumina bead chip analysis. The identified genes that were differentially regulated by SIRT6 knockdown were analyzed by the Ingenuity Pathway Analysis program to determine the SIRT6 gene function in endothelial cells. (A, B) Top five groups of genes categorized by molecular and cellular functions (A) and physiological system development and function (B). (C) Top five canonical pathways affected by SIRT6 knockdown. (D) Heat map showing the genes specifically involved in cell cycle transition regulation. Rows show individual genes, and columns show triplicate samples. Up- and downregulated genes are shown in red and green, respectively. (E) A gene functional association network for the genes involved in cell cycle transition regulation. The intensity of the node colors (red and green) indicates the degree of up- and downregulation.