Pelayo R, Gutiérrez-Gil B, Marina H, Fonseca P A S, Alonso-García M, Arranz J J, Suárez-Vega A
Departamento de Producción Animal, Facultad de Veterinaria, Universidad de León, Campus de Vegazana s/n, 24071 León, Spain.
Departamento de Producción Animal, Facultad de Veterinaria, Universidad de León, Campus de Vegazana s/n, 24071 León, Spain.
J Dairy Sci. 2024 Dec;107(12):11269-11282. doi: 10.3168/jds.2024-25009. Epub 2024 Sep 28.
Mammary gland infections constitute a significant challenge in dairy sheep, affecting productivity and welfare. Temporal RNA sequencing (RNA-Seq) provide a valuable approach to evaluate the evolution of the host defensive molecular mechanisms triggered by mastitis caused by external agents or events. This study aimed to characterize the transcriptomic response of sheep mammary glands to an intramammary inflammation induced with an Escherichia coli LPS inoculation based on RNA-Seq samples generated from milk somatic cells collected at 3 time points: pre-inoculation (0 h), and 6 h and 24 h post-LPS inoculation. The differential expression analyses between the analyzed time points were performed using 2 statistical approaches: one parametric (DESeq2) and one nonparametric (Wilcoxon rank-sum test). The differentially expressed genes (DEG) commonly identified by both approaches encompass 5,872 for the 0 h versus 6 h comparison, 4,063 for the 0 h versus 24 h comparison, and 1,034 for the 6 h versus 24 h comparison. At both 6 and 24 h, transcriptomic data highlighted a significant decrease in the expression of genes linked to metabolic processes crucial for milk protein and lipid synthesis within the mammary gland. Concurrently, increased expression of genes related to the neutrophil attraction was observed for 6 and 24 h, with differences in gene expression between DEG with the highest expression at 6 h, related to T cell activation, type I interferon-mediated signaling pathway, and 24 h, related to cell-cell neutrophil adhesion extravasation or epithelial cell proliferation. In summary, this study reveals how the sheep mammary gland transcriptome responds dynamically to an LPS inoculation, providing a comprehensive understanding of how gene expression patterns evolve over time and shedding light on the molecular mechanisms driving the initial defensive response of the mammary gland against potential inflammatory challenges.
乳腺感染是奶羊养殖中的一项重大挑战,会影响生产力和羊的健康。时间分辨RNA测序(RNA-Seq)为评估由外部因素或事件引起的乳腺炎所触发的宿主防御分子机制的演变提供了一种有价值的方法。本研究旨在基于从3个时间点采集的乳体细胞生成的RNA-Seq样本,表征绵羊乳腺对大肠杆菌脂多糖接种诱导的乳腺内炎症的转录组反应,这3个时间点分别为:接种前(0小时)、脂多糖接种后6小时和24小时。使用两种统计方法对分析的时间点之间进行差异表达分析:一种是参数方法(DESeq2),另一种是非参数方法(Wilcoxon秩和检验)。两种方法共同鉴定出的差异表达基因(DEG),在0小时与6小时的比较中有5872个,在0小时与24小时的比较中有4063个,在6小时与24小时的比较中有1034个。在6小时和24小时时,转录组数据均突出显示,与乳腺内乳蛋白和脂质合成至关重要的代谢过程相关的基因表达显著下降。同时,在6小时和24小时时观察到与中性粒细胞吸引相关的基因表达增加,在6小时时表达最高的DEG与T细胞活化、I型干扰素介导的信号通路相关,在24小时时与细胞间中性粒细胞粘附渗出或上皮细胞增殖相关的基因表达存在差异。总之,本研究揭示了绵羊乳腺转录组如何对脂多糖接种做出动态反应,全面了解了基因表达模式如何随时间演变,并阐明了驱动乳腺对潜在炎症挑战的初始防御反应的分子机制。