Genetic hallmark of susceptible cows through macrophage profiling of MAP infected cows: Johne's-disease-associated SNPs impair macrophage function

约翰氏病(JD)是一种由一种名为禽分枝杆菌SSP的细胞内病原体引起的反刍动物的衰弱和慢性肠炎。副结核(MAP)。JD给加拿大乳制品行业造成了巨大的经济损失，估计每年损失1500-9000万美元。正在进行研究，以确定早期和更准确的标记；使用明智的基因选择策略来提高宿主抗病能力也是乳制品行业的一项重要战略。在目前的研究计划中，我们将研究牛的巨噬细胞，这是一种特殊的抗原提呈免疫细胞，负责吞噬病原体。 有证据表明，MAP需要巨噬细胞才能生存和传播。我们假设，在易感奶牛中，巨噬细胞发生了基因改变，这使得MAP能够增殖并逃避正常的分枝杆菌杀死过程。利用下一代RNA测序技术，我们将研究MAP挑战的巨噬细胞的功能特性。RNA-Seq是一种有效的鉴定方法 表达数量性状基因座(EQTL)和与候选基因转录本及其亚型类型相关的致病DNA多态。具体目标是：(1)识别eQTL，该eQTL定义区分受感染的健康/抗性奶牛的遗传差异；(2)识别基因(和 目的：(1)确定牛巨噬细胞处理细胞内病原体能力的有利或无效等位基因(S)及其异构体)以及巨噬细胞MAP征用中涉及的调控途径；(3)确定区分不敏感奶牛的功能性遗传变异；以及(4)确认有益或功能失调的等位基因对牛巨噬细胞处理细胞内病原体能力的影响。这些信息在基因选择中是相关的，因为它们排除了疾病易感性。 将这项研究的结果(基因组信息)整合到传统的年轻母牛选择和后代测试计划中，可以更好、更准确和快速地提高加拿大奶牛群对牛副结核病的抵抗力。

Johne's disease (JD) is a debilitating and chronic enteritis in ruminants caused by an intracellular pathogen called Mycobacterium avium ssp. paratuberculosis (MAP). JD causes significant economic losses in the Canadian dairy industry, estimated at $15-$90 million annually. Research is ongoing to identify early and more accurate markers; improvement of host disease resistance using a judicious genetic selection strategy is also an important strategy of the dairy industry. In the present research proposal, we will study cow's macrophages which are a type of specialized antigen presenting immune cells responsible for the engulfment of pathogens. There is evidence that MAP requires macrophages for its survival and dissemination. We hypothesize that macrophage is genetically altered in susceptible cows which allows MAP to proliferate and escape the normal mycobacterial killing process. With the use of next-generation RNA sequencing technology, we will study the functional properties of macrophages challenged with MAP. RNA-Seq is an effective way of identifying expression quantitative trait loci (eQTL) and those causative DNA polymorphisms associated with candidate gene transcripts and their types of isoforms. The specific objectives are: (1) to identify eQTL which define the genetic differences that discriminate MAP infected from healthy/resistant cows; (2) to identify the genes (and their isoforms) and the regulatory pathways involved in MAP requisitioning of macrophage; (3) to identify functional genetic variations that delineate susceptible from non-susceptible cows; and (4) to confirm the influence of beneficial or dysfunctional allele (s) on the capacity of the bovine macrophage to process intracellular pathogens. This information is relevant in genetic selection, as they preclude disease susceptibility. An integration of the findings of this research (genomic information), into the conventional young sire selection and progeny testing program could yield a better, more accurate and rapid genetic improvement of resistance to bovine paratuberculosis in Canadian dairy herds.