Jiminez Janelle, Timsit Edouard, Orsel Karin, van der Meer Frank, Guan Le Luo, Plastow Graham
Department of Agricultural, Food and Nutritional Science, Livestock Gentec, University of Alberta, Edmonton, AB, Canada.
Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada.
Front Genet. 2021 Mar 8;12:627623. doi: 10.3389/fgene.2021.627623. eCollection 2021.
Bovine respiratory disease (BRD) is one of the main factors leading to morbidity and mortality in feedlot operations in North America. A complex of viral and bacterial pathogens can individually or collectively establish BRD in cattle, and to date, most disease characterization studies using transcriptomic techniques examine bronchoalveolar and transtracheal fluids, lymph node, and lung tissue as well as nasopharyngeal swabs, with limited studies investigating the whole-blood transcriptome. Here, we aimed to identify differentially expressed (DE) genes involved in the host immune response to BRD using whole blood and RNA sequencing. Samples were collected from heifers (average arrival weight = 215.0 ± 5.3 kg) with ( = 25) and without ( = 18) BRD at a commercial feedlot in Western Canada. RNAseq analysis showed a distinct whole-blood transcriptome profile between BRD and non-BRD heifers. Further examination of the DE genes revealed that those involved in the host inflammatory response and infectious disease pathways were enriched in the BRD animals, while gene networks associated with metabolism and cell growth and maintenance were downregulated. Overall, the transcriptome profile derived from whole blood provided evidence that a distinct antimicrobial peptide-driven host immune response was occurring in the animals with BRD. The blood transcriptome of the BRD animals shows similarities to the transcriptome profiles obtained from lung and bronchial lymph nodes in other studies. This suggests that the blood transcriptome is a potential diagnostic tool for the identification of biomarkers of BRD infection and can be measured in live animals and used to further understand infection and disease in cattle. It may also provide a useful tool to increase the understanding of the genes involved in establishing BRD in beef cattle and be used to investigate potential therapeutic applications.
牛呼吸道疾病（BRD）是导致北美饲养场牛发病和死亡的主要因素之一。多种病毒和细菌病原体可单独或共同引发牛的BRD，迄今为止，大多数使用转录组技术的疾病特征研究都检测支气管肺泡和气管内液体、淋巴结、肺组织以及鼻咽拭子，而对全血转录组的研究有限。在此，我们旨在通过全血和RNA测序确定参与宿主对BRD免疫反应的差异表达（DE）基因。在加拿大西部的一个商业饲养场，从患有（n = 25）和未患有（n = 18）BRD的小母牛（平均进场体重 = 215.0 ± 5.3 kg）中采集样本。RNAseq分析显示，BRD和非BRD小母牛之间存在明显不同的全血转录组图谱。对DE基因的进一步检测发现，参与宿主炎症反应和传染病途径的基因在BRD动物中富集，而与代谢以及细胞生长和维持相关的基因网络则下调。总体而言，来自全血的转录组图谱提供了证据，表明在患有BRD的动物中正在发生由抗菌肽驱动的独特宿主免疫反应。BRD动物的血液转录组与其他研究中从肺和支气管淋巴结获得的转录组图谱相似。这表明血液转录组是识别BRD感染生物标志物的潜在诊断工具，可在活体动物中进行检测，并用于进一步了解牛的感染和疾病情况。它还可能提供一个有用的工具，以增进对肉牛中引发BRD的相关基因的理解，并用于研究潜在的治疗应用。
