IDH2 and GLUD1 Depletion Arrests Embryonic Development through an H4K20me3 Epigenetic Barrier in Porcine Parthenogenetic Embryos

Isocitrate dehydrogenase 2 (IDH2) and glutamate dehydrogenase 1 (GLUD1) are key enzymes involved in the production of α-ketoglutarate, a metabolite central to the tricarboxylic acid cycle and glutamine metabolism. In this study, we focused on the impact of IDH2 and GLUD1 on early porcine embryonic development by knocking down IDH2 and GLUD1 via dsRNA microinjection. The knockdown resulted in reduced α-ketoglutarate levels, leading to delayed embryonic development, decreased blastocyst formation rate, increased apoptosis, reduced blastomere proliferation, and lower expression of the pluripotency marker OCT4. Additionally, IDH2 and GLUD1 knockdown caused abnormally high levels of H4K20me3 at the 4-cell stage, likely resulting in transcriptional repression of embryonic genome activation (EGA) related genes. Importantly, the knockdown of H4K20me3 methyltransferase KMT5C and supplementation with exogenous α-ketoglutarate reduced H4K20me3 expression and partially rescued these defects, suggesting a critical role of IDH2 and GLUD1 in the epigenetic regulation and proper development of porcine embryos. This study underscores the significance of IDH2 and GLUD1 in maintaining normal embryonic development through their influence on α-ketoglutarate production and subsequent epigenetic modifications.