Generation of mouse embryonic stem cell lines from zona-free nuclear transfer embryos

Pluripotent stem cells would have great potential in cell therapies and drug development when genetically matched with the patient; thus, histocompatible cells could be used in transplantation therapy or as a source of patient-specific cells for drug testing. Pluripotent embryonic stem cells (ESCs)-generated via somatic cell nuclear transfer (SCNT) or parthenogenesis (pESC)-are potential sources of histocompatible cells and tissues for transplantation. Earlier studies used the piezoelectric microinjection (PEM) technique for nuclear transfer (NT) in mouse. No specific studies examined zona-free (ZF) NT as an alternative NT method to generate genetically matched ESCs of a nuclear donor. In this study, we compared the efficiency of nuclear transfer-derived ESC (ntESC) line establishment from ZF-NT, ZF-parthenogenetic (PGA), and ZF-fertilized embryos with that of the PEM-NT method. Different nuclei donor cells [cumulus, ESC, and mouse embryonic fibroblast (MEF)] were used and the efficiency of ntESC derivation was investigated, along with their in vitro characterization. The ZF-NT method's efficiency was higher than that of the PEM-NT using cumulus cells. When ESCs and cumulus cells were used as nuclear donor cells, they resulted in significantly higher ZF-NT-derived ntESC line establishment rates compared to MEF cells. In conclusion, the nuclear donor cell type significantly affected the efficiency of ntESC line establishment, and the ZF-NT method was efficient to establish pluripotent ntESC lines.