Lee Hye Jeong, Choi Na Young, Lee Seung-Wong, Lee Yukyeong, Ko Kisung, Kim Gwang Jun, Hwang Han Sung, Ko Kinarm
Departement of Stem Cell Biology, Konkuk University School of Medicine, Seoul, Korea.
Center for Stem Cell Research, Institute of Advanced Biomedical Science, Konkuk University, Seoul, Korea.
Int J Stem Cells. 2019 Mar 30;12(1):31-42. doi: 10.15283/ijsc18084.
Genomic imprinting modulates growth and development in mammals and is associated with genetic disorders. Although uniparental embryonic stem cells have been used to study genomic imprinting, there is an ethical issue associated with the destruction of human embryos. In this study, to investigate the genomic imprinting status in human neurodevelopment, we used human uniparental induced pluripotent stem cells (iPSCs) that possessed only maternal alleles and differentiated into neural cell lineages.
Human somatic iPSCs (hSiPSCs) and human parthenogenetic iPSCs (hPgiPSCs) were differentiated into neural stem cells (NSCs) and named hSi-NSCs and hPgi-NSCs respectively. DNA methylation and gene expression of imprinted genes related neurodevelopment was analyzed during reprogramming and neural lineage differentiation.
The DNA methylation and expression of imprinted genes were altered or maintained after differentiation into NSCs. The imprinting status in NSCs were maintained after terminal differentiation into neurons and astrocytes. In contrast, gene expression was differentially presented in a cell type-specific manner.
This study suggests that genomic imprinting should be determined in each neural cell type because the genomic imprinting status can differ in a cell type-specific manner. In addition, the model established in this study would be useful for verifying the epigenetic alteration of imprinted genes which can be differentially changed during neurodevelopment in human and for screening novel imprinted genes related to neurodevelopment. Moreover, the confirmed genomic imprinting status could be used to find out an abnormal genomic imprinting status of imprinted genes related with neurogenetic disorders according to uniparental genotypes.
基因组印记调控哺乳动物的生长发育，并与遗传疾病相关。尽管单亲胚胎干细胞已被用于研究基因组印记，但存在与人类胚胎破坏相关的伦理问题。在本研究中，为了调查人类神经发育中的基因组印记状态，我们使用了仅具有母本等位基因并分化为神经细胞谱系的人类单亲诱导多能干细胞（iPSC）。
将人类体细胞iPSC（hSiPSC）和人类孤雌生殖iPSC（hPgiPSC）分化为神经干细胞（NSC），分别命名为hSi-NSC和hPgi-NSC。在重编程和神经谱系分化过程中，分析了与神经发育相关的印记基因的DNA甲基化和基因表达。
分化为NSC后，印记基因的DNA甲基化和表达发生改变或维持。NSC在终末分化为神经元和星形胶质细胞后，印记状态得以维持。相比之下，基因表达以细胞类型特异性方式呈现差异。
本研究表明，由于基因组印记状态可能因细胞类型而异，因此应在每种神经细胞类型中确定基因组印记。此外，本研究建立的模型将有助于验证印记基因的表观遗传改变，这些改变在人类神经发育过程中可能会发生差异变化，并有助于筛选与神经发育相关的新印记基因。此外，确认的基因组印记状态可用于根据单亲基因型找出与神经遗传疾病相关的印记基因的异常基因组印记状态。
