Abstract

Gene expression profiles of blood can reflect the physiopathologic status of the immune system. The dynamic microRNA (miRNA) expression profiles of peripheral blood from pigs at different developmental stages, and how differential expression of miRNAs might relate to immune system development, are unknown. In this study, peripheral blood samples taken at five developmental stages were used to construct 15 miRNA libraries (three biological replicates/stage): 0 days (newborn), 30 days (weaning), 60 days (weaned), and 180 and 360 days (puberty). We identified 295 known mature miRNAs. Hierarchical clustering of the miRNA expression profile showed significant differences between individuals at the neonatal and postnatal stages. Functional enrichment analysis revealed that miRNAs differentially expressed between pairwise comparisons of the developmental stages were over-represented in immune-related pathways such as toll-like receptor signaling. The time-course of expression of the over-representated miRNAs exhibited a pattern of steady decline over time, for both the complete miRNA compendium and immune-related miRNAs. We identified six marker miRNAs that were highly negatively correlated with chronologic age and enriched for genes involved in immune-related pathways. This study of a peripheral blood miRNA transcriptome offers insight into immune system development in swine and provides a resource for pig genome annotation.

摘要

血液的基因表达谱可以反映免疫系统的病理生理状态。来自不同发育阶段的猪外周血的动态 microRNA (miRNA) 表达谱，以及 miRNA 的差异表达如何与免疫系统发育相关，尚不清楚。在这项研究中，在五个发育阶段采集的外周血样本用于构建 15 个 miRNA 文库（三个生物学重复/阶段）：0 天（新生儿）、30 天（断奶）、60 天（断奶）以及 180 天和 360 天（青春期）。我们鉴定了 295 个已知的成熟 miRNA。miRNA 表达谱的分层聚类显示在新生儿和出生后阶段的个体之间存在显着差异。功能富集分析显示，在发育阶段的成对比较之间差异表达的 miRNA 在免疫相关通路（如 toll 样受体信号传导）中过度表达。对于完整的 miRNA 纲要和免疫相关的 miRNA，过度表达的 miRNA 的表达时间过程表现出随时间稳定下降的模式。我们确定了六种标记 miRNA，它们与实际年龄高度负相关，并富含参与免疫相关途径的基因。这项关于外周血 miRNA 转录组的研究提供了对猪免疫系统发育的深入了解，并为猪基因组注释提供了资源。对于完整的 miRNA 纲要和免疫相关的 miRNA，过度表达的 miRNA 的表达时间过程表现出随时间稳定下降的模式。我们确定了六种标记 miRNA，它们与实际年龄高度负相关，并富含参与免疫相关途径的基因。这项关于外周血 miRNA 转录组的研究提供了对猪免疫系统发育的深入了解，并为猪基因组注释提供了资源。对于完整的 miRNA 纲要和免疫相关的 miRNA，过度表达的 miRNA 的表达时间过程表现出随时间稳定下降的模式。我们确定了六种标记 miRNA，它们与实际年龄高度负相关，并富含参与免疫相关途径的基因。这项关于外周血 miRNA 转录组的研究提供了对猪免疫系统发育的深入了解，并为猪基因组注释提供了资源。