Brain transcriptomes of harbor seals demonstrate gene expression patterns of animals undergoing a metabolic disease and a viral infection
- Published
- Accepted
- Subject Areas
- Aquaculture, Fisheries and Fish Science, Marine Biology, Microbiology, Veterinary Medicine, Virology
- Keywords
- marine mammal, phocine herpesvirus, fatty acid metabolism, high-throughput sequencing, Burkholderia
- Copyright
- © 2016 Rosales et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2016. Brain transcriptomes of harbor seals demonstrate gene expression patterns of animals undergoing a metabolic disease and a viral infection. PeerJ Preprints 4:e2457v1 https://doi.org/10.7287/peerj.preprints.2457v1
Abstract
Diseases of marine mammals can be difficult to diagnose because of the life history and protected status of these animals. Stranded marine mammals have been a particularly useful resource to discover and comprehend the diseases that plague these top predators. Additionally, advancements in high-throughput sequencing (HTS) has contributed to the discovery of novel pathogens in these animals. In this study, we use a combination of HTS and stranded harbor seals (Phoca vitulina) to better understand a known and unknown brain disease. To do this, we used transcriptomics to evaluate brain tissues from seven neonatal harbor seals that expired from an unknown cause of death (UCD) and compared them to four neonatal harbor seals that had confirmed phocine herpesvirus (PhV-1) infections in the brain. Comparing these two disease states we found that UCD animals showed a significant abundance of fatty acid metabolic transcripts in their brain tissue, thus we speculate that a fatty acid metabolic dysregulation contributed to the death of these animals. Furthermore, we were able to describe the response of four young harbor seals with PhV-1 infections in the brain. PhV-1 infected animals showed a significant ability to mount an innate and adaptive immune response, especially to combat viral infections. Our data also suggests that PhV-1 can hijack host pathways for DNA packaging and exocytosis. This is the first study to use transcriptomics in marine mammals to understand host and viral interactions and assess the death of stranded marine mammals with an unknown disease. Furthermore, we show the value of applying transcriptomics on stranded marine mammals for disease characterization.
Author Comment
This is a submission to PeerJ for review.
Supplemental Information
Length and counts of the harbor seal transcriptome
(A) The length and count distribution of the harbor seal transcriptome with transcript lengths < 8,500 and (B) the length and count distribution of the harbor seal transcriptome with transcript lengths > 8,500.
Significant differentially expressed genes (DEGs, padj < 0.05) that fell within GO category “defense response to bacteria.”
Heatmap hierarchical clustering of normalized gene counts expressed in rlog transformation (row z-score) from PhV1com and UCD harbor seals.