Vitamin C down-regulates the H3K9me3-dependent heterochromatin in buffalo fibroblasts via PI3K/PDK1/SGK1/KDM4A signal axis

The success of reprogramming is dependent on the reprogramming factors enriched in the cytoplasm of recipient oocytes and the potential of donor nucleus to be reprogrammed. Histone 3 lysine 9 trime-thylation (H3K9me3) was identified as a major epigenetic barrier impeding complete reprogramming. Treating donor cell with vitamin C (Vc) can enhance the developmental potential of cloned embryos, but the underlying mechanisms still need to be elucidated. In this study, we found that 20mg/mL Vc could promote proliferation and inhibit apoptosis of BFFs, as well as down-regulate the H3K9me3-dependent heterochromatin and increase chromatin accessibility. Inhibited the expression of KDM4A resulted in increasing apoptosis rate and the H3K9me3-dependent heterochromatin, which can be restored by Vc. Moreover, Vc up-regulated the expression of KDM4A through PI3K/PDK1/SGK1 pathway. Inhibiting any factor in the signal axis of this PI3K pathway not only suppressed the activity of KDM4A but also sub-stantially increased the level of H3K9me3 modification and the expression of the HP1a protein. Finally, Vc can rescue those negative effects induced by the blocking the PI3K/PDK1/SGK1 pathway. Collectively, Vc can down-regulate the H3K9me3-dependent heterochromatin in BFFs via PI3K/PDK1/SGK1/KDM4A signal axis, suggesting that Vc can turn the chromatin status of donor cells to be reprogrammed more easily.(c) 2023 Published by Elsevier Inc.

Automated summary

The success of reprogramming depends on the reprogramming factors in recipient oocytes and the reprogrammability of donor nuclei. Histone 3 lysine 9 trimethylation (H3K9me3) is a major epigenetic barrier to reprogramming. Vitamin C (Vc) treatment can enhance the development potential of cloned embryos. This study reveals that Vc can down-regulate H3K9me3-dependent heterochromatin in BFFs through the PI3K/PDK1/SGK1/KDM4A signaling pathway.