Wang Ou, Liang Guanxiang, McAllister Tim A, Plastow Graham, Stanford Kim, Selinger Brent, Guan Le Luo
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada.
Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, AB, Canada.
PLoS One. 2016 Mar 9;11(3):e0151284. doi: 10.1371/journal.pone.0151284. eCollection 2016.
Super-shedder cattle are a major disseminator of E. coli O157:H7 into the environment, and the terminal rectum has been proposed as the primary E. coli O157:H7 colonization site. This study aimed to identify host factors that are associated with the super-shedding process by comparing transcriptomic profiles in rectal tissue collected from 5 super-shedder cattle and 4 non-shedder cattle using RNA-Seq. In total, 17,859 ± 354 genes and 399 ± 16 miRNAs were detected, and 11,773 genes were expressed in all animals. Fifty-eight differentially expressed (DE) genes (false discovery rate < 0.05) including 11 up-regulated and 47 down-regulated (log 2 (fold change) ranged from -5.5 to 4.2), and 2 up-regulated DE miRNAs (log 2 (fold change) = 2.1 and 2.5, respectively) were identified in super-shedders compared to non-shedders. Functional analysis of DE genes revealed that 31 down-regulated genes were potentially associated with reduced innate and adaptive immune functions in super-shedders, including 13 lymphocytes membrane receptors, 3 transcription factors and 5 cytokines, suggesting the decreased key host immune functions in the rectal tissue of super-shedders, including decreased quantity and migration of immune cells such as lymphocytes, neutrophils and dendritic cells. The up-regulation of bta-miR-29d-3p and the down regulation of its predicted target gene, regulator of G-protein signaling 13, suggested a potential regulatory role of this miRNA in decreased migration of lymphocytes in super-shedders. Based on these findings, the rectal tissue of super-shedders may inherently exhibit less effective innate and adaptive immune protection. Further study is required to confirm if such effect on host immunity is due to the nature of the host itself or due to actions mediated by E. coli O157:H7.
超级排菌牛是大肠杆菌O157:H7向环境中传播的主要散播者，有人提出直肠末端是大肠杆菌O157:H7的主要定植部位。本研究旨在通过RNA测序比较5头超级排菌牛和4头非排菌牛直肠组织中的转录组图谱，以确定与超级排菌过程相关的宿主因素。总共检测到17,859 ± 354个基因和399 ± 16个miRNA，所有动物中均表达了11,773个基因。与非排菌牛相比，在超级排菌牛中鉴定出58个差异表达（DE）基因（错误发现率<0.05），其中包括11个上调基因和47个下调基因（log2（倍数变化）范围为-5.5至4.2），以及2个上调的DE miRNA（log2（倍数变化）分别为2.1和2.5）。对DE基因的功能分析表明，31个下调基因可能与超级排菌牛先天和适应性免疫功能降低有关，包括13个淋巴细胞膜受体、3个转录因子和5个细胞因子，这表明超级排菌牛直肠组织中关键的宿主免疫功能下降，包括淋巴细胞、中性粒细胞和树突状细胞等免疫细胞数量减少和迁移能力下降。bta-miR-29d-3p的上调及其预测靶基因G蛋白信号调节因子13的下调表明，该miRNA可能在超级排菌牛淋巴细胞迁移减少中发挥潜在调节作用。基于这些发现，超级排菌牛的直肠组织可能天生表现出较弱的先天和适应性免疫保护作用。需要进一步研究以确认这种对宿主免疫的影响是由于宿主本身的性质还是由大肠杆菌O157:H7介导的作用所致。
