Song Yukun, Hai Erhan, Zhang Nan, Zhang Yu, Wang Junlan, Han Xitong, Zhang Jiaxin
Inner Mongolia Key Laboratory of Sheep & Goat Genetics Breeding and Reproduction, College of Animal Science, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia, 010018, China.
BMC Genomics. 2025 Feb 1;26(1):97. doi: 10.1186/s12864-025-11291-9.
In mammals, female fertility is influenced by the result of follicular development (ovulation or atresia). Follicular atresia is a complex physiological process that results in the degeneration of oocytes from the ovary. However, the molecular mechanisms of oocyte degeneration and key protein markers of follicular atresia remain unclear. In this study, we investigated the complex transcriptional regulatory mechanisms and protein profiles in oocytes and follicular fluid in atretic follicle stages using single-cell RNA sequencing and tandem mass tag proteomics.
First, through paired analysis of different follicle development stages, we identified 175 atresia-specific genes and eight candidate oocyte-secreted factors, including PKG1, YTHDF2, and MYC. Meanwhile, we also characterized unique features of the oocyte transcriptional landscape in the atretic follicle stage that displayed cell death-related transcriptional changes and mechanisms, such as autophagy (TBK1 and IRS4), necroptosis (PKR), and apoptosis (MARCKS). Moreover, we identified atresia-specific genes, namely FTH1, TF, and ACSL4, which may participate in regulation of oocyte ferroptosis in atretic follicles through a series of mechanisms including ferritinophagy, ferritin transport, and lipid metabolism. Additionally, we uncovered 333 differentially expressed proteins that may coordinate follicular atresia and revealed key pathways, such as negative regulation of angiogenesis, metabolic pathways, and transcription and mRNA splicing, that lead to oocyte degeneration. Finally, by combining transcriptome and proteomics analyses, we identified two oocyte-secreted biomarkers, PGK1 and ANGPT2, that may be associated with follicular atresia.
In conclusion, our work offers a thorough characterization of oocyte transcription mechanism and follicular fluid protein changes in ovine atretic follicles, which offers a crucial reference for analyzing the mechanism of follicular atresia and establishing an oocyte quality assessment system in sheep.
在哺乳动物中，雌性生育能力受卵泡发育结果（排卵或闭锁）的影响。卵泡闭锁是一个复杂的生理过程，会导致卵巢中的卵母细胞退化。然而，卵母细胞退化的分子机制以及卵泡闭锁的关键蛋白标志物仍不清楚。在本研究中，我们使用单细胞RNA测序和串联质谱标签蛋白质组学，研究了闭锁卵泡阶段卵母细胞和卵泡液中的复杂转录调控机制和蛋白质谱。
首先，通过对不同卵泡发育阶段的配对分析，我们鉴定出175个闭锁特异性基因和8个候选卵母细胞分泌因子，包括PKG1、YTHDF2和MYC。同时，我们还表征了闭锁卵泡阶段卵母细胞转录图谱的独特特征，其显示出与细胞死亡相关的转录变化和机制，如自噬（TBK1和IRS4）、坏死性凋亡（PKR）和凋亡（MARCKS）。此外，我们鉴定出闭锁特异性基因，即FTH1、TF和ACSL4，它们可能通过包括铁蛋白自噬、铁蛋白转运和脂质代谢在内的一系列机制参与闭锁卵泡中卵母细胞铁死亡的调控。此外，我们发现了333种差异表达的蛋白质，它们可能协调卵泡闭锁，并揭示了导致卵母细胞退化的关键途径，如血管生成的负调控、代谢途径以及转录和mRNA剪接。最后，通过结合转录组和蛋白质组分析，我们鉴定出两种可能与卵泡闭锁相关的卵母细胞分泌生物标志物PGK1和ANGPT2。
总之，我们的工作全面表征了绵羊闭锁卵泡中卵母细胞转录机制和卵泡液蛋白质变化，为分析卵泡闭锁机制和建立绵羊卵母细胞质量评估系统提供了关键参考。
