Caniçais Carla, Sobral Daniel, Vasconcelos Sara, Cunha Mariana, Pinto Alice, Mesquita Guimarães Joana, Santos Fátima, Barros Alberto, Dória Sofia, Marques C Joana
Genetics Unit, Department of Pathology, Faculty of Medicine University of Porto (FMUP), 4200-319, Portugal; ICBAS- School of Medicine and Biomedical Sciences, University of Porto, 4050-313, Porto, Portugal.
Genomics and Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health Doutor Ricardo Jorge (INSA), 1649-016, Lisbon, Portugal.
Dev Biol. 2025 Mar;519:55-64. doi: 10.1016/j.ydbio.2024.12.004. Epub 2024 Dec 15.
Human oocytes are highly specialized cells with the capacity to store and regulate mRNAs during oocyte maturation, in preparation for post-fertilization steps. Here we performed single-oocyte transcriptomic analysis of human oocytes in three meitoic maturation stages - Germinal Vesicle (GV; n = 6), Metaphase I (MI; n = 6) and Metaphase II (MII; n = 7). Single-oocyte transcriptomic analysis revealed that the total number of expressed genes progressively decreased from GV to MII stages, with 9660 genes being transcribed in GV, 8734 in MI and 5889 in MII. The same tendency was observed for the number of uniquely expressed genes, with 1328 uniquely expressed genes in GV, 401 in MI and 72 in MII. GO analysis of the uniquely expressed genes showed distinct terms in GV oocytes such as transferase activity, organonitrogen compound metabolic process and ncRNA processing. Analysis of Differentially Expressed Genes (DEGs) between the three maturation stages revealed 1165 DEGs between GV and MII oocytes, with 635 being upregulated and 528 downregulated, 42 DEGs between GV and MI, with 38 being upregulated and 4 downregulated, and no significant changes in gene expression between MI and MII oocytes. Comprehensive analysis of epigenetic regulators showed high expression of several histone-modifying enzymes, namely deacetylases, acetylases, lysine demethylases and methyltransferases, and DNA methylation regulators, namely the maintenance methyltransferase DNMT1 and its co-regulators DPPA3 and UHRF1. Some of these epigenetic regulators were differentially expressed between maturation stages, namely SIRT3, SIRT6, KDM3AP1, KMT2E, DNMT1, DPPA3 and the MEST and RASGRF1 imprinted genes. Our study contributes with important information on the transcriptional landscape of human oocytes in different stages of meiotic maturation, providing important insights into candidate biomarkers of human oocyte quality.
人类卵母细胞是高度特化的细胞，在卵母细胞成熟过程中具有储存和调节mRNA的能力，为受精后的步骤做准备。在此，我们对处于减数分裂三个成熟阶段的人类卵母细胞进行了单细胞转录组分析，即生发泡期（GV；n = 6）、中期I（MI；n = 6）和中期II（MII；n = 7）。单细胞转录组分析显示，从GV期到MII期，表达基因的总数逐渐减少，GV期有9660个基因被转录，MI期有8734个，MII期有5889个。独特表达基因的数量也呈现相同趋势，GV期有1328个独特表达基因，MI期有401个，MII期有72个。对独特表达基因的GO分析显示，GV卵母细胞中有不同的术语，如转移酶活性、有机氮化合物代谢过程和ncRNA加工。对三个成熟阶段之间差异表达基因（DEG）的分析显示，GV和MII卵母细胞之间有1165个DEG，其中635个上调，528个下调；GV和MI之间有42个DEG，其中38个上调，4个下调；MI和MII卵母细胞之间基因表达无显著变化。对表观遗传调节因子的综合分析显示，几种组蛋白修饰酶高度表达，即去乙酰化酶、乙酰化酶、赖氨酸去甲基化酶和甲基转移酶，以及DNA甲基化调节因子，即维持甲基转移酶DNMT1及其共调节因子DPPA3和UHRF1。其中一些表观遗传调节因子在成熟阶段之间差异表达，即SIRT3、SIRT6、KDM3AP1、KMT2E、DNMT1、DPPA3以及印记基因MEST和RASGRF1。我们的研究提供了关于人类卵母细胞减数分裂不同成熟阶段转录图谱 的重要信息，为深入了解人类卵母细胞质量的候选生物标志物提供了重要见解。
