Putative Epimutagens in Maternal Peripheral and Cord Blood Samples Identified Using Human Induced Pluripotent Stem Cells

Figure 2

Epimutagen screening of hiPSCs. (a) Visualization of heterochromatin structure in nuclei by DAPI staining and immunofluorescence using anti-HP1α antibody. The intensities of signals of DAPI and HP1α on the dotted lines (a-b) were measured using the ImageJ software and plotted. The strong HP1α signals (filled triangles) were confirmed to merge with the DAPI signals. (b) Altered heterochromatin formation after treating hiPSCs with the known epimutagen TSA. hiPSCs were treated with TSA (0, 2, 20, or 40 nM) for 96 h, and heterochromatin was detected using immunofluorescence with anti-HP1α antibodies (red) and DAPI counterstaining (blue). The number of HP1α signals per interphase nucleus was counted using ImageJ software. The number of signals is shown as a box plot. Statistical comparisons of signal number were performed using the Wilcoxon test. . Scale bar = 10 μm. (c) The number of HP1α signals in hiPSCs exposed to serum levels (1x) or 10-fold increased concentrations (10x) of DEP, Hg, cotinine, Se, or S-421 for 96 h were analyzed. The upper panel shows images of cells exposed to 1x chemicals, and the lower panel presents the number of signals as a box plot. Scale bar = 10 μm. (d) Exposure to the 10x concentrations of TCP, DMP, DETP, DMDTP, and MEHP. All heterochromatin analyses were performed at least twice independently.

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