A moderate increase in ambient temperature modulates the Atlantic cod (Gadus morhua) spleen transcriptome response to intraperitoneal viral mimic injection

Abstract

BackgroundAtlantic cod (Gadus morhua) reared in sea-cages can experience large variations in temperature, and these have been shown to affect their immune function. We used the new 20K Atlantic cod microarray to investigate how a water temperature change which, simulates that seen in Newfoundland during the spring-summer (i.e. from 10°C to 16°C, 1°C increase every 5 days) impacted the cod spleen transcriptome response to the intraperitoneal injection of a viral mimic (polyriboinosinic polyribocytidylic acid, pIC).ResultsThe temperature regime alone did not cause any significant increases in plasma cortisol levels and only minor changes in spleen gene transcription. However, it had a considerable impact on the fish spleen transcriptome response to pIC [290 and 339 significantly differentially expressed genes between 16°C and 10°C at 6 and 24 hours post-injection (HPI), respectively]. Seventeen microarray-identified transcripts were selected for QPCR validation based on immune-relevant functional annotations. Fifteen of these transcripts (i.e. 88%), including DHX58, STAT1, IRF7, ISG15, RSAD2 and IκBα, were shown by QPCR to be significantly induced by pIC.ConclusionsThe temperature increase appeared to accelerate the spleen immune transcriptome response to pIC. We found 41 and 999 genes differentially expressed between fish injected with PBS vs. pIC at 10°C and sampled at 6HPI and 24HPI, respectively. In contrast, there were 656 and 246 genes differentially expressed between fish injected with PBS vs. pIC at 16°C and sampled at 6HPI and 24HPI, respectively. Our results indicate that the modulation of mRNA expression of genes belonging to the NF-κB and type I interferon signal transduction pathways may play a role in controlling temperature-induced changes in the spleen’s transcript expression response to pIC. Moreover, interferon effector genes such as ISG15 and RSAD2 were differentially expressed between fish injected with pIC at 10°C vs. 16°C at 6HPI. These results substantially increase our understanding of the genes and molecular pathways involved in the negative impacts of elevated ambient temperature on fish health, and may also be valuable to our understanding of how accelerated global climate change could impact cold-water marine finfish species.

Atlantic salmon (Salmo salar) liver transcriptome response to diets containing Camelina sativa products

“…normality), and were presented as mean ± SE. For QPCR fold-change calculation, overall fold up-regulation was calculated as 2 A − B as in Hori et al (2012), where A is the mean of log 2 transformed RQ from an experimental diet (e.g. 100CO or 100COSEFM) group, and B is the mean of log 2 transformed RQ from the control diet (FO) group.…”

Interferon regulatory factor 10 (IRF10): Cloning in orange spotted grouper, Epinephelus coioides, and evolutionary analysis in vertebrates

“…In Atlantic cod (G. morhua), two isoforms of IRF10 splice variants were identified with notable difference in the timing and intensity of response to poly(I:C) and/or bacterial challenge. The expression of both two IRF10 isoforms was significant up-regulate by poly(I:C), and the highest expression of the long isoform in response to poly(I:C) challenge occurred at 24 hpi at 10 C and 6 hpi at 16 C, while the greatest increase of short isoform was observed at 6 hpi at both 10 C and 16 C [29,30]. Regarding bacterial challenge, the significant increase in the expression of long isoform was observed only at 24 hpi (2.4 fold) and the expression of the short one occurred at 6 hpi at 10 C (1.37 fold) and 16 C (2.7 fold) and 24 hpi at 10 C (1.48 fold), indicating that these two variants may have distinct roles in cod immune response [29,30].…”

“…The expression of both two IRF10 isoforms was significant up-regulate by poly(I:C), and the highest expression of the long isoform in response to poly(I:C) challenge occurred at 24 hpi at 10 C and 6 hpi at 16 C, while the greatest increase of short isoform was observed at 6 hpi at both 10 C and 16 C [29,30]. Regarding bacterial challenge, the significant increase in the expression of long isoform was observed only at 24 hpi (2.4 fold) and the expression of the short one occurred at 6 hpi at 10 C (1.37 fold) and 16 C (2.7 fold) and 24 hpi at 10 C (1.48 fold), indicating that these two variants may have distinct roles in cod immune response [29,30]. In the present study, the highest increase in the expression of grouper IRF10 at mRNA level was also observed at 6 hpi after poly(I:C) treatment, which is quite consistent with the result observed in flounder and zebrafish and the shorter isoform of cod IRF10, implying that grouper IRF10 has an important role in antiviral response as reported in other teleost fish and chicken [25,27,28].…”

Temperature-dependent regulation of gene expression in poly (I:C)-treated Japanese flounder, Paralichthys olivaceus

“…Recently, Dios et al [15] demonstrated that zebrafish (Danio rerio) treated with poly (I:C) have different expression profiles of immune-related genes such as Toll-like receptor 3 (TLR3), Mx, and interferon regulatory factor 3 (IRF3) between low (15 C) and high (28 C) temperatures. Interferon stimulatory gene 15 (ISG15) expression in Atlantic cod after poly (I:C) injection was higher at 16 C than 10 C at 6 hpi [9]. Likewise, we previously reported that Mx expression in sevenband grouper injected with poly (I:C) was regulated by temperature [10].…”