Submitted to: Veterinary Research
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/30/2011
Publication Date: 12/6/2011
Citation: Li, R.W., Rinaldi, M., Capuco, A.V. 2011. Characterization of the abomasal transcriptome for mechanisms of resistance to gastrointestinal nematodes in cattle. Veterinary Research. 42(1):114. Interpretive Summary: Gastrointestinal parasites have a significant economic impact on the American cattle industry. Limited knowledge in our understanding of molecular mechanisms underlying host resistance has hindered the development of vaccines as well as applied breeding for parasite-resistant cattle. In this study, we conducted an in-depth transcriptomic analysis of the bovine abomasum during parasitic infections. We identified multiple signaling pathways that were significantly impacted in resistant cattle. Our findings will facilitate our understanding of basic regulatory processes in host resistance and development of a pan-vaccine that confers protection against all major parasite species.
Technical Abstract: The abomasal transcriptome of Angus cattle in response to parasitic infection was characterized at a depth of 23.7 million sequences per sample using RNA-seq. These cattle displayed a distinctly separate resistance phenotype in terms of fecal egg counts. Approximately 65.3% of the 23,633 bovine genes were expressed in the fundic abomasum. 13,758 genes were expressed in all samples tested and are likely to represent the core components of the bovine abomasal transcriptome. The gene (BT14427) with the most abundant transcript was located on chromosome 29 with unknown functions, consisting of 10.4% of sequences in the transcriptome. PIGR (1.6%), Complement C3 (0.7%), and Immunoglobulin J chain (0.5%) were among the most abundant transcripts in the transcriptome. Among the 203 genes impacted, 64 were significantly over-expressed in resistant animals at a stringent cutoff (FDR <5%). Among the 94,224 intron-exon junctions identified, 133 were uniquely present: 90 were observed only in resistant animals while 43 were present only in susceptible animals. Gene Ontology (GO) enrichment of the genes under study was predominantly associated with lipid metabolism, which was confirmed by an independent pathway analysis. Several pathways, such as FXR/RXR activation, LXR/RXR activation, LPS/IL-1 mediated inhibition of RXR function, and arachidonic acid metabolism, were impacted in resistant animals (P <0.01), which are potentially involved in the development of parasite resistance in cattle. Our results provided insights into the development of host immunity to gastrointestinal nematode infection and will facilitate our understanding of the mechanism underlying host resistance.