Figure 1

Infinium methylation microarray analysis of Methylation changes in DEHP-exposed human placenta samples. (A) The flowchart shows how the pipeline of raw data was processed. DNA methylation was performed using the high-resolution Infinium MethylationEPIC BeadChip Kit interrogating about 850,000 methylation sites quantitatively across the genome at single-nucleotide resolution. By utilizing a cut-off p-value threshold of greater than 0.05 and an FDR of 10%, a total of 1254 probes displaying a minimum of 10% differential methylation were identified. (B) Density of DNA methylation level for 12 human placenta samples exposed to DEHP; blue lines: low DEHP exposure (n = 6), red lines: high DEHP exposure (n = 6). Individual probes with beta (β)-values (range 0–1) are approximate representations of the absolute methylation percentage of specific CpG sites within the sample population. Beta value = 1 indicates complete methylation; beta value = 0 represents no methylation. (C) Density of 10% differentially DNA methylated probes of all samples. Hypomethylation was observed in the DEHP high group (red line), as compared to DEHP low group (blue line). (D) Heatmap showing the 10% differentially DNA methylated probes; left panel: low DEHP exposure; right panel: high DEHP exposure. Heatmap showing differentially methylated cytosine (DMC) sites across the two different exposure dosages of DEHP. Most of the probes observed were hypomethylation in DEHP (red line: methylated, blue line: unmethylated).