Oxidative damage reprograms the Hippo-WNT network via X-linked Kdm6a to activate blastocyst dormancy and prevent offspring tumorigenesis.

In vitro fertilization (IVF) has been associated with an increased risk of tumorigenesis in offspring. Our previous research indicated that oxidative damage-induced X-chromosome aneuploidy (XCA) in IVF mouse embryos may contribute to tumorigenesis in offspring. However, the tumorigenic mechanisms underlying this phenomenon remain unclear. The present study elucidates that an elevated number of X chromosomes leads to excessive transcription of Xist , resulting in aberrant X-chromosome inactivation (XCI). This abnormal XCI subsequently inhibits the expression of the X-linked lysine demethylase 6A (Kdm6a), which is followed by an increase in repressive marker H3K27me3 and a decrease in active markers H3K27ac/H3K4me3. To investigate the epigenetic mechanisms involved in offspring tumorigenesis, we employed CUT&Tag technology to map genome-wide profiles of H3K27ac/H3K4me3/H3K27me3 in IVF blastocysts. We found that Kdm6a-dependent histone modifications exhibited a close relationship with leukemia by regulating cancer pathways, particularly Hippo/Yap1 and Wnt (Wnt/β-catenin and Wnt/RhoA) signalings in oxidatively damaged IVF embryos. Kdm6a plasmid and antioxidant EGCG were found to maintain epigenetic stability and antagonize the effects of ROS on the Hippo and Wnt pathways. We concluded that oxidative damage-induced loss of Kdm6a participated in offspring tumorigenesis via oncogenic RhoA/β-catenin activation and tumor-suppressive Hippo inactivation during IVF. However, leukemia or hepatic tumors was not increased in the offspring derived from oxidatively damaged IVF blastocysts. Our further analysis revealed that Kdm6a-dependent histone modifications play a crucial role in regulating pluripotency of embryonic stem cells. Kdm6a plasmid antagonized the effects of ROS on the formation of rosette-like structures and the expression of naive gene Oct4 as well as primed gene Otx2 in IVF blastocysts. This implies that Kdm6a is essentail for the naive-to-primed transition and activation of blastocysts during implantation. We hypothesize that loss of Kdm6a adversely affects blastocyst implantation, thereby to prevent the birth of offspring with an increased risk of tumorigenesis.