Department of Animal Science, Texas A&M University, College Station, TX, USA.
Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, College Station, TX, USA.
Biol Reprod. 2022 Nov 14;107(5):1279-1295. doi: 10.1093/biolre/ioac152.
The one-carbon metabolism (OCM) pathway provides purines and thymidine for synthesis of nucleic acids required for cell division, and S-adenosyl methionine for polyamine and creatine syntheses and the epigenetic regulation of gene expression. This study aimed to determine if serine hydroxymethyltransferase 2 (SHMT2), a key enzyme in the OCM pathway, is critical for ovine trophectoderm (oTr) cell function and conceptus development by inhibiting translation of SHMT2 mRNA using a morpholino antisense oligonucleotide (MAO). In vitro treatment of oTr cells with MAO-SHMT2 decreased expression of SHMT2 protein, which was accompanied by reduced proliferation (P = 0.053) and migration (P < 0.05) of those cells. Intrauterine injection of MAO-SHMT2 in ewes on Day 11 post-breeding tended to decrease the overall pregnancy rate (on Days 16 and 18) compared with MAO-control (3/10 vs. 7/10, P = 0.07). The three viable conceptuses (n = 2 on Day 16 and n = 1 on Day 18) recovered from MAO-SHMT2 ewes had only partial inhibition of SHMT2 mRNA translation. Conceptuses from the three pregnant MAO-SHMT2 ewes had similar levels of expression of mRNAs and proteins involved in OCM as compared with conceptuses from MAO-control ewes. These results indicate that knockdown of SHMT2 protein reduces proliferation and migration of oTr cells (in vitro) to decrease elongation of blastocysts from spherical to elongated forms. These in vitro effects suggest that increased embryonic deaths in ewes treated with MAO-SHMT2 are the result of decreased SHMT2-mediated trophectoderm cell proliferation and migration supporting a role for the OCM pathway in survival and development of ovine conceptuses.
一碳代谢（OCM）途径为细胞分裂所需的核酸合成提供嘌呤和胸苷，为多胺和肌酸合成以及基因表达的表观遗传调控提供 S-腺苷甲硫氨酸。本研究旨在通过使用反义寡核苷酸（MO）抑制 SHMT2 mRNA 的翻译来确定一碳代谢途径中的关键酶丝氨酸羟甲基转移酶 2（SHMT2）是否对绵羊滋养层（oTr）细胞功能和胚胎发育至关重要。体外用 MO-SHMT2 处理 oTr 细胞会降低 SHMT2 蛋白的表达，这伴随着这些细胞增殖（P=0.053）和迁移（P<0.05）减少。在配种后第 11 天向绵羊子宫内注射 MO-SHMT2 与 MO-对照相比，总体妊娠率（第 16 和 18 天）有下降的趋势（3/10 对 7/10，P=0.07）。从 MO-SHMT2 绵羊中回收的三个存活胚胎（第 16 天 2 个，第 18 天 1 个）仅部分抑制了 SHMT2 mRNA 的翻译。与 MO-对照绵羊的胚胎相比，来自三个妊娠 MO-SHMT2 绵羊的胚胎中涉及 OCM 的 mRNA 和蛋白质的表达水平相似。这些结果表明，SHMT2 蛋白的敲低降低了 oTr 细胞的增殖和迁移（体外），从而减少了从球形到拉长形式的囊胚的伸长。这些体外效应表明，用 MO-SHMT2 处理的绵羊胚胎中胚胎死亡增加是由于 SHMT2 介导的滋养层细胞增殖和迁移减少所致，这表明 OCM 途径在绵羊胚胎的存活和发育中起作用。
