Chemical simulation of hypoxia in donor cells improves development of somatic cell nuclear transfer‐derived embryos and increases abundance of transcripts related to glycolysis

To improve efficiency of somatic cell nuclear transfer (SCNT), it is necessary to modify differentiated donor cells to become more amendable for reprogramming by the oocyte cytoplasm. A key feature that distinguishes somatic/differentiated cells from embryonic/undifferentiated cells is cellular metabolism, with somatic cells using oxidative phosphorylation (OXPHOS) while embryonic cells utilize glycolysis. Inducing metabolic reprogramming in donor cells could improve SCNT efficiency by priming cells to become more embryonic in nature before SCNT hypoxia inducible factor 1‐α (HIF1‐α), a transcription factor that allows for cell survival in low oxygen, promotes a metabolic switch from OXPHOS to glycolysis. We hypothesized that chemically stabilizing HIF1‐α in donor cells by use of the hypoxia mimetic, cobalt chloride (CoCl2), would promote this metabolic switch in donor cells and subsequently improve the development of SCNT embryos. Donor cell treatment with 100 µM CoCl2 for 24 hr preceding SCNT upregulated messenfer RNA abundance of glycolytic enzymes, improved SCNT development to the blastocyst stage and quality, and affected gene expression in the blastocysts. After transferring blastocysts created from CoCl2‐treated donor cells to surrogates, healthy cloned piglets were produced. Therefore, shifting metabolism toward glycolysis in donor cells by CoCl2 treatment is a simple, economical way of improving the in vitro efficiency of SCNT and is capable of producing live animals. Hypoxic culture of donor cells used for porcine somatic cell nuclear transfer (SCNT) has previously been shown to induce cellular metabolic reprogramming and improve development of cloned embryos. In this study, treating donor cells with a hypoxia mimetic, cobalt chloride, further improved SCNT efficiency as compared with hypoxic culture. Therefore, cobalt chloride treatment can be used as a simple and economical alternative to hypoxic culture for porcine SCNT donor cells.