Integrated Expression Profiling and Genome-Wide Analysis of ChREBP Targets Reveals the Dual Role for ChREBP in Glucose-Regulated Gene Expression
Figure 7
Correlation of ChREBP binding with gene expression.
(A) Heat map view of a sample of ChREBP target genes exhibiting greater than two-fold expression changes in the high glucose state. (B) KS plot. The ChIP-seq peaks were analyzed for their representation within an expression array dataset from no vs. high glucose-treated HepG2 cells as described in the text. All genes in the microarray were ranked by posterior probability of differential expression (PPDE) on the x-axis and the graph plots by the running enrichment score. (C, D) Experimental validation of microarray results of 12 selected ChREBP target genes. HepG2 cells were incubated under 2.7 mM glucose conditions for 16 h. Cells were then either kept in 0 or 25 mM glucose medium for 8 h and harvested for RNA preparation. The levels of target genes were determined by qRT-PCR. Expression levels were normalized to expression of cyclophilin and mRNA levels in no glucose treated cells were set to 1. Values represent the mean of triplicate samples ± S.D. (E) Effects of ChREBP gene silencing on the expression of ChREBP target genes. HepG2 cells were transfected with 20 nmol of either ChREBP siRNA or scrambled siRNA and incubated for 40 h in 2.7 mM DMEM. Then the cells were cultured in 25 mM glucose. After 8 h, total RNA was extracted and analyzed for the expression of ChREBP target genes by qRT-PCR. Data represent the mean ± S.D. of three independent transfections.