Developmental Characteristics of Cloned Embryos Reconstructed with Induced Pluripotent Stem Cells in Pigs

Abstract

In general, cloned pigs have been produced using the somatic cell nuclear transfer (SCNT) technique with various types of somatic cells; however, the SCNT technique has disadvantages not only in its low efficiency but also in the development of abnormal clones. This study aimed to compare early embryonic development and quality of SCNT embryos with those of induced pluripotent stem cells (iPSCs) NT embryos (iPSC-NTs). Ear fibroblast cells were used as donor cells and iPSCs were generated from these cells by lentiviral transduction with human six factors (Oct4, Sox2, c-Myc, Nanog, Klf4 and Lin28). Blastocyst formation rate in iPSC-NT (23/258, 8.9%) was significantly lower than that in SCNT (46/175, 26.3%; p < 0.05). Total cell number in blastocysts was similar between two groups, but blastocysts in iPSC-NT had a lower number of apoptotic cells than in SCNT (2.0 ± 0.6 vs. 9.8 ± 2.9, p < 0.05). Quantitative PCR data showed that apoptosis-related genes (bax, caspase-3, and caspase-9) were highly expressed in SCNT than iPSC-NT (p < 0.05). Although an early development rate was low in iPSC-NT, the quality of cloned embryos from porcine iPSC was higher than that of embryos from somatic cells. Therefore, porcine iPSCs could be used as a preferable cell source to create a clone or transgenic animals by using the NT technique.

Keywords

• apoptosis
• cloning efficiency
• in vitro development
• porcine induced pluripotent stem cells
• somatic cell nuclear transfer