Figure 7.

GPX2 and GSH Contribute to DNA Damage Protection in iPSCs

(A) Transcript levels of GPX2 and GSTA2 in iPSCs, fibroblasts, and cell lines of different tumor entities. The mRNA levels of the two GSH-dependent enzymes were analyzed by qRT-PCR relative to GAPDH. A representative dataset is shown.

(B) Combined GSH depletion and GPX2 knockdown impair DNA damage protection of iPSCs. L2 iPSCs were incubated with 25 nM GPX2-specific, GSTA2-specific, or non-targeting (NT) siRNA. After 72 hr, GSx was depleted by the addition of BSO/DMF for 1 hr, followed by exposure to 2 mM H₂O₂ for 5 min. (Top) Measurement of mtDNA damage using the LORD-Q assay is shown. Results represent means ± SD of three independent experiments. ^∗p < 0.05. (Bottom) Confirmation of the GPX2 and GSTA2 knockdown by western blotting is shown.

(C) Overexpression of GPX2 is sufficient to confer increased resistance to DNA damage in fibroblasts. L2 fibroblasts were transduced with lentiviral vectors for YFP-coupled GPX2 or the YFP control. Then, 48 hr post-infection, cells were treated with 2 mM H₂O₂ for 5 min. (Top) Measurement of mtDNA damage by LORD-Q analysis is shown. Results represent means ± SD from three independent experiments. p = 0.002. (Bottom) Confirmation of GPX2 overexpression by western blotting using an anti-GPX2 antibody is shown.