Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China.
Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China; Department of Nephrology, Beijing Key Laboratory for Chronic Renal Disease and Blood Purification, Key Laboratory of Major Diseases in Children, National Center for Children's Health, Beijing Children's Hospital Affiliated to Capital Medical University, Beijing, China.
J Nutr Biochem. 2023 Jun;116:109297. doi: 10.1016/j.jnutbio.2023.109297. Epub 2023 Mar 11.
Proper Dlk1-Dio3 imprinting plays a critical role in embryogenesis, and folic acid deficiency may affect the imprinting of this locus through epigenetic regulation. However, whether and how folic acid directly impacts the imprinting status of Dlk1-Dio3 to affect neural development remain unclear. Here, we found decreased IG-DMR (intergenic -differentially methylated regions) methylation in the folate-deficient encephalocele in humans, suggesting that abnormal Dlk1-Dio3 imprinting status is related to neural tube defects (NTDs) caused by folate deficiency. Similar results were obtained with folate-deficient embryonic stem cells. By miRNA chip analysis, folic acid deficiency led to changes in multiple miRNAs, including the upregulation of 15 miRNAs located in the Dlk1-Dio3 locus. Real-time PCR confirmed that seven of these miRNAs were upregulated, especially miR-370. In contrast to normal embryonic development, in which expression of miR-370 is highest at E9.5, the abnormally high and sustained expression of miRNA-370 in folate-deficient E13.5 embryos may contribute to NTDs. In addition, we found that DNMT3A (de novo DNA methyltransferases 3A) is a direct target gene of miR-370 in neural cells, and DNMT3A participates in the role of miR-370 in inhibiting cell migration. Finally, in the folate-deficient mouse model, Dlk1-Dio3 epigenetic activation was found in fetal brain tissue, along with the upregulation of miR-370 and the downregulation of DNMT3A. Collectively, our findings demonstrate a pivotal role of folate in the epigenetic regulation of Dlk1-Dio3 imprinting during neurogenesis, revealing an elegant mechanism for the activation of Dlk1-Dio3 locus miRNAs in folic acid deficiency.
正确的 Dlk1-Dio3 印迹对于胚胎发生至关重要，叶酸缺乏可能通过表观遗传调控影响该基因座的印迹。然而，叶酸是否以及如何直接影响 Dlk1-Dio3 的印迹状态，从而影响神经发育仍不清楚。在这里，我们发现叶酸缺乏的无脑畸形人类胚胎中 IG-DMR（基因间-差异甲基化区域）甲基化减少，这表明异常的 Dlk1-Dio3 印迹状态与叶酸缺乏引起的神经管缺陷（NTDs）有关。在叶酸缺乏的胚胎干细胞中也得到了类似的结果。通过 miRNA 芯片分析，叶酸缺乏导致多个 miRNA 发生变化，包括位于 Dlk1-Dio3 基因座的 15 个 miRNA 的上调。实时 PCR 证实其中 7 个 miRNA 上调，特别是 miR-370。与正常胚胎发育不同，miR-370 在 E9.5 时表达最高，而在叶酸缺乏的 E13.5 胚胎中异常高且持续的 miR-370 表达可能导致 NTDs。此外，我们发现 DNMT3A（从头 DNA 甲基转移酶 3A）是神经细胞中 miR-370 的直接靶基因，DNMT3A 参与 miR-370 抑制细胞迁移的作用。最后，在叶酸缺乏的小鼠模型中，在胎脑组织中发现 Dlk1-Dio3 表观遗传激活，同时 miR-370 上调和 DNMT3A 下调。总之，我们的研究结果表明，叶酸在神经发生过程中对 Dlk1-Dio3 印迹的表观遗传调控中起着关键作用，揭示了叶酸缺乏时 Dlk1-Dio3 基因座 miRNA 激活的一种优雅机制。
