Feugang Jean M, Gad Ahmed, Menjivar Nico G, Ishak Ghassan M, Gebremedhn Samuel, Gastal Melba O, Dlamini Notsile H, Prochazka Radek, Gastal Eduardo L, Tesfaye Dawit
Department of Animal and Dairy Sciences, Mississippi State University, Mississippi State, MS, 39762, USA.
Animal Reproduction and Biotechnology Laboratory (ARBL), Department of Biomedical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, 80523, USA.
J Anim Sci Biotechnol. 2024 Oct 9;15(1):137. doi: 10.1186/s40104-024-01097-2.
Ovarian follicular fluid (FF) is a dynamic environment that changes with the seasons, affecting follicle development, ovulation, and oocyte quality. Cells in the follicles release tiny particles called extracellular vesicles (EVs) containing vital regulatory molecules, such as microRNAs (miRNAs). These miRNAs are pivotal in facilitating communication within the follicles through diverse signaling and information transfer forms. EV-coupled miRNA signaling is implicated to be associated with ovarian function, follicle and oocyte growth and response to various environmental insults. Herein, we investigated how seasonal variations directly influence the ovulatory and anovulatory states of ovarian follicles and how are they associated with follicular fluid EV-coupled miRNA dynamics in horses.
Ultrasonographic monitoring and follicular fluid aspiration of preovulatory follicles in horses during the anovulatory (spring: non-breeding) and ovulatory (spring, summer, and fall: breeding) seasons and subsequent EV isolation and miRNA profiling identified significant variation in EV-miRNA cargo content. We identified 97 miRNAs with differential expression among the groups and specific clusters of miRNAs involved in the spring transition (miR-149, -200b, -206, -221, -328, and -615) and peak breeding period (including miR-143, -192, -451, -302b, -100, and let-7c). Bioinformatic analyses showed enrichments in various biological functions, e.g., transcription factor activity, transcription and transcription regulation, nucleic acid binding, sequence-specific DNA binding, p53 signaling, and post-translational modifications. Cluster analyses revealed distinct sets of significantly up- and down-regulated miRNAs associated with spring anovulatory (Cluster 1) and summer ovulation-the peak breeding season (Clusters 4 and 6).
The findings from the current study shed light on the dynamics of FF-EV-coupled miRNAs in relation to equine ovulatory and anovulatory seasons, and their roles in understanding the mechanisms involved in seasonal shifts and ovulation during the breeding season warrant further investigation.
卵巢卵泡液（FF）是一个随季节变化的动态环境，影响卵泡发育、排卵和卵母细胞质量。卵泡中的细胞释放称为细胞外囊泡（EVs）的微小颗粒，其中含有重要的调节分子，如微小RNA（miRNAs）。这些miRNAs在通过多种信号传导和信息传递形式促进卵泡内通讯方面起着关键作用。EV偶联的miRNA信号传导被认为与卵巢功能、卵泡和卵母细胞生长以及对各种环境损伤的反应有关。在此，我们研究了季节变化如何直接影响马卵巢卵泡的排卵和不排卵状态，以及它们如何与卵泡液中EV偶联的miRNA动态相关。
在不排卵（春季：非繁殖期）和排卵（春季、夏季和秋季：繁殖期）季节对马的排卵前卵泡进行超声监测和卵泡液抽吸，随后进行EV分离和miRNA分析，发现EV-miRNA货物含量存在显著差异。我们在各组中鉴定出97种差异表达的miRNAs，以及参与春季过渡期（miR-149、-200b、-206、-221、-328和-615）和繁殖高峰期（包括miR-143、-192、-451、-302b、-100和let-7c）的特定miRNA簇。生物信息学分析显示在各种生物学功能中存在富集，例如转录因子活性、转录和转录调控、核酸结合、序列特异性DNA结合、p53信号传导和翻译后修饰。聚类分析揭示了与春季不排卵（聚类1）和夏季排卵——繁殖高峰期（聚类4和6）相关的明显上调和下调的miRNA集。
本研究结果揭示了FF-EV偶联的miRNAs与马排卵和不排卵季节相关的动态变化，它们在理解繁殖季节季节性变化和排卵所涉及机制中的作用值得进一步研究。
