Treating donor cells with 2-PCPA corrects aberrant histone H3K4 dimethylation and improves cloned goat embryo development

<p>Epigenetic modifications extensively occur in mammalian embryonic development and cell differentiation process. They play an essential role in the reprogramming of nuclei during somatic cell nuclear transfer (SCNT) and subsequent <i>in vitro</i> embryonic development. Recently, SCNT embryos have been verified to contain a subnormal level of histone H3K4 dimethylation (H3K4me2) in contrast to <i>in vitro</i> fertilized embryos. This finding suggested that increasing H3K4me2 levels may ameliorate the aberrant development of cloned embryos. In this study, we investigated the influence of treating donor cells with trans-2-Phenylcyclopropylamine (2-PCPA), a specific inhibitor of lysine-specific demethylase 1 (LSD1), on embryogenesis, H3K4me2 level, and gene expression in cloned goat embryos. Treated goat fetal fibroblast cells (GFFs) with 2-PCPA served as donor cells for subsequent SCNT. Results showed that H3K4me2 levels in treated GFFs increased gradually with the increasing 2-PCPA concentration (<i>p</i> < 0.05) and had no obvious influence in cell viability. The 2-PCPA-induced up-regulation of H3K4me2 levels led to G0/G1 cell cycle arrest and the difference was significant at 2μM compared with the control group (<i>p</i> < 0.05). Interestingly, the development rate of goat SCNT embryos <i>in vitro</i> was significantly improved and aberrant H3K4me2 levels were effectively corrected in 2-PCPA-treated SCNT embryos in contrast to that in SCNT control embryos. Moreover, 2-PCPA treatment promoted the mRNA expression of key developmental genes <i>Oct4</i> and <i>Sox2</i> (<i>p</i> < 0.05) without affecting the expression levels of imprinted genes <i>IGF2R</i> and <i>H19</i> in goat SCNT embryos. These results indicated that abnormal H3K4me2 status can be corrected and SCNT embryo development can be promoted through treatment of donor cells with 2-PCPA.</p> <p><b>Abbreviations:</b> SCNT: somatic cell nuclear transfer; H3K4me2: H3K4 dimethylation; 2-PCPA: trans-2-Phenylcyclopropylamine; LSD1: lysine-specific demethylase 1; GFFs: goat fetal fibroblast cells; IVF: <i>in vitro</i> fertilization; iPS: induced pluripotent stem; PBS: phosphate-buffered saline; IVM: <i>in vitro</i> maturation; RNAPII: RNA polymerase II; HMTs: histone methyltransferase</p