Department of Gynecology and Obstetrics, Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510150, China.
Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology and Key Laboratory of Assisted Reproduction, Ministry of Education, Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing 100191, China.
Mol Hum Reprod. 2021 Feb 27;27(3). doi: 10.1093/molehr/gaab012.
Human zygotes are difficult to obtain for research because of limited resources and ethical debates. Corrected human tripronuclear (ch3PN) zygotes obtained by removal of the extra pronucleus from abnormally fertilized tripronuclear (3PN) zygotes are considered an alternative resource for basic scientific research. In the present study, eight-cell and blastocyst formation efficiency were significantly lower in both 3PN and ch3PN embryos than in normal fertilized (2PN) embryos, while histone H3 lysine 9 trimethylation (H3K9me3) levels were much higher. It was speculated that the aberrant H3K9me3 level detected in ch3PN embryos may be related to low developmental competence. Microinjection of 1000 ng/µl lysine-specific demethylase 4A (KDM4A) mRNA effectively reduced the H3K9me3 level and significantly increased the developmental competence of ch3PN embryos. The quality of ch3PN zygotes improved as the grading criteria, cell number and pluripotent expression significantly increased in response to KDM4A mRNA injection. Developmental genes related to zygotic genome activation (ZGA) were also upregulated. These results indicate that KDM4A activates the transcription of the ZGA program by enhancing the expression of related genes, promoting epigenetic modifications and regulating the developmental potential of ch3PN embryos. The present study will facilitate future studies of ch3PN embryos and could provide additional options for infertile couples.
人类受精卵难以获取，因为资源有限且存在伦理争议。从异常受精的三原核（3PN）受精卵中去除多余的原核，得到校正的人类三原核（ch3PN）受精卵，被认为是基础科学研究的一种替代资源。在本研究中，3PN 和 ch3PN 胚胎的 8 细胞和囊胚形成效率均显著低于正常受精（2PN）胚胎，而组蛋白 H3 赖氨酸 9 三甲基化（H3K9me3）水平则显著升高。推测 ch3PN 胚胎中检测到的异常 H3K9me3 水平可能与其发育能力低下有关。将 1000ng/μl 的赖氨酸特异性去甲基化酶 4A（KDM4A）mRNA 微注射到 ch3PN 胚胎中，可有效降低 H3K9me3 水平，并显著提高 ch3PN 胚胎的发育能力。ch3PN 胚胎的质量也得到了改善，因为其分级标准、细胞数量和多能性表达均显著增加，这是对 KDM4A mRNA 注射的反应。与合子基因组激活（ZGA）相关的发育基因也上调。这些结果表明，KDM4A 通过增强相关基因的表达，促进表观遗传修饰，调节 ch3PN 胚胎的发育潜能，激活 ZGA 程序的转录。本研究将有助于未来对 ch3PN 胚胎的研究，并为不孕夫妇提供更多选择。
