α-Ketoglutarate enhances epigenetic remodeling and developmental competence in porcine SCNT embryos

Zygotic genome activation failure contributes to the low developmental efficiency of porcine somatic cell nuclear transfer (SCNT) embryos. We show that α-ketoglutarate improves transcriptional activation, epigenetic remodeling, and embryo development in SCNT embryos, supporting its potential use for improving nuclear reprogramming efficiency.

Abstract: Incomplete zygotic genome activation (ZGA) is a major barrier limiting the developmental competence of somatic cell nuclear transfer (SCNT) embryos in pigs. α-Ketoglutarate (α-KG), a key metabolic intermediate and cofactor for α-KG-dependent dioxygenases, has been implicated in epigenetic remodeling during early embryogenesis. In this study, we investigated whether α-KG supplementation could improve developmental potential and ZGA-associated events in porcine SCNT embryos. Treatment with α-KG improved cleavage progression, increased blastocyst formation rates, increased total blastocyst cell number and inner cell mass cell number, and reduced apoptosis and DNA damage. In addition, α-KG improved microtubule organization and actin distribution during early cleavage stages, contributing to more coordinated cell division. Mechanistically, α-KG increased global 5-hydroxymethylcytosine (5hmC) levels and elevated the abundance of activating histone marks, including H3K4me3 and H3K27ac. Expression of several ZGA-associated genes, including DUXA, ZSCAN4, EIF1A, and KLF17, was significantly increased following α-KG supplementation, accompanied by enhanced nascent RNA synthesis. Notably, inhibition of TET enzymes with Bobcat339 attenuated the effects of α-KG on 5hmC accumulation, transcriptional activity, and embryo development. Collectively, these findings indicate that α-KG improves developmental competence and is associated with enhanced epigenetic remodeling in porcine SCNT embryos, at least in part through TET-associated pathways, providing a potential strategy for improving nuclear reprogramming efficiency in animal cloning.