Variation in the Ovine Abomasal Lymph Node Transcriptome between Breeds Known to Differ in Resistance to the Gastrointestinal Nematode

Abstract

Texel lambs are known to be more resistant to gastrointestinal nematode (GIN) infection than Suffolk lambs, with a greater ability to limit infection. The objectives of this study were to: 1) profile the whole transcriptome of abomasal lymph node tissue of GIN-free Texel and Suffolk lambs; 2) identify differentially expressed genes and characterize the immune-related biological pathways and networks associated with these genes. Abomasal lymph nodes were collected from Texel (n = 6) and Suffolk (n = 4) lambs aged 19 weeks that had been GIN-free since 6 weeks of age. Whole transcriptome profiling was performed using RNA-seq on the Illumina platform. At the time of conducting this study, a well annotated Ovine genome was not available and hence the sequence reads were aligned with the Bovine (UMD3.1) genome. Identification of differentially expressed genes was followed by pathway and network analysis. The Suffolk breed accounted for significantly more of the differentially expressed genes, (276 more highly expressed in Suffolk v 162 in Texel; P < 0.001). The four most significant differentially expressed pathways were all related to immunity and were classified as: Role of Pattern Recognition Receptors in Recognition of Bacteria and Viruses, Activation of IRF by Cytosolic Pattern Recognition Receptors, Role of RIG-I-like Receptors in Antiviral Innate Immunity, and Interferon Signaling. Of significance is the fact that all of these four pathways were more highly expressed in the Suffolk. These data suggest that in a GIN-free environment, Suffolk lambs have a more active immune profile relative to the Texel: this immune profile may contribute to the poorer efficiency of response to a GIN challenge in the Suffolk breed compared to the Texel breed.

A comparative analysis of the transcriptome profiles of liver and muscle tissue in pigs divergent for feed efficiency

“…Potentially, the vaccination program elicited an immune response in early life which persisted to slaughter, thus up regulating immune related genes and subsequently altering the ranking of the DE genes. Previously, a gene expression profile associated with viral immunity in adult sheep was attributed to vaccination in early life [28]. Interestingly, the expression pattern of several members of the gene families adenylate synthetase-like protein (OAS) and interferon-induced protein (IFIT) were common between the two studies.…”

Genome‐wide association study to identify genetic loci associated with gastrointestinal nematode resistance in Katahdin sheep

“…Interestingly, a locus on chromosome 3 was within the gene complement C3a receptor 1 (C3AR1) and the locus on chromosome 16 was 87 kb upstream of the gene integrin subunit alpha 2 (ITGA2) . C3AR1 has been reported to be differentially expressed in more susceptible vs resistant sheep (Ahmed et al ) and has been associated with the Th1 immune response (Ghannam et al ). Integrin subunit alpha genes have been found to be upregulated in more resistant animals under GIN infection (Zhang et al ).…”

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“…The number of DEG identified in our study was relatively high compared to RNA sequencing studies of lymph node tissues comparing resistant and susceptible sheep [24,25] and lower than the number of DEG in the blood transcriptome of resistant and susceptible goats [46]. There may be variations among species and tissues.…”