a Department of Ocean Sciences, Memorial University of Newfoundland, St. John's, NL A1C 5S7, Canada.
Genome. 2013 Oct;56(10):567-76. doi: 10.1139/gen-2013-0090. Epub 2013 Aug 31.
Exposure to elevated temperature is an inherent feature of Atlantic cod (Gadus morhua) sea-cage culture in some regions (e.g., Newfoundland) and may also become an increasingly prevalent challenge for wild fish populations because of accelerated climate change. Therefore, understanding how elevated temperatures impacts the immune response of this commercially important species may help to reduce the potential negative impacts of such challenges. Previously, we investigated the impacts of moderately elevated temperature on the antiviral responses of Atlantic cod (Hori et al. 2012) and reported that elevated temperature modulated the spleen transcriptome response to polyriboinosinic polyribocytidylic acid (pIC, a viral mimic). Herein, we report a complementary microarray study that investigated the impact of the same elevated temperature regime on the Atlantic cod spleen transcriptome response to intraperitoneal (IP) injection of formalin-killed Aeromonas salmonicida (ASAL). Fish were held at two different temperatures (10 °C and 16 °C) prior to immune stimulation and sampled 6 and 24 h post-injection (HPI). In this experiment, we identified 711 and 666 nonredundant ASAL-responsive genes at 6HPI and 24HPI, respectively. These included several known antibacterial genes, including hepcidin, cathelicidin, ferritin heavy subunit, and interleukin 8. However, we only identified 15 differentially expressed genes at 6HPI and 2 at 24HPI (FDR 1%) when comparing ASAL-injected fish held at 10 °C versus 16 °C. In contrast, the same comparisons with pIC-injected fish yielded 290 and 339 differentially expressed genes (FDR 1%) at 6HPI and 24HPI, respectively. These results suggest that moderately elevated temperature has a lesser effect on the Atlantic cod spleen transcriptome response to ASAL (i.e., the antibacterial response) than to pIC (i.e., antiviral response). Thus, the impacts of high temperatures on the cod's immune response may be pathogen dependent.
暴露在高温下是北大西洋鳕鱼（Gadus morhua）在某些地区（如纽芬兰）进行网箱养殖的固有特征，由于气候变化加速，这也可能成为野生鱼类种群日益普遍的挑战。因此，了解高温如何影响这种商业上重要的物种的免疫反应，可能有助于减少这些挑战的潜在负面影响。此前，我们研究了中度高温对北大西洋鳕鱼抗病毒反应的影响（Hori 等人，2012 年），并报告称高温调节了脾脏对聚肌胞苷酸（pIC，一种病毒模拟物）的转录组反应。在此，我们报告了一项补充的微阵列研究，该研究调查了相同的高温条件对大西洋鳕鱼脾脏转录组对腹腔内（IP）注射福尔马林灭活鲑鱼气单胞菌（ASAL）的反应的影响。在免疫刺激之前，鱼在两种不同的温度（10°C 和 16°C）下饲养，并在注射后 6 小时和 24 小时（HPI）取样。在这项实验中，我们分别在 6HPI 和 24HPI 时鉴定了 711 个和 666 个非冗余的 ASAL 反应基因。这些基因包括几种已知的抗菌基因，如铁调素、cathelicidin、铁蛋白重链和白细胞介素 8。然而，当比较在 10°C 和 16°C 下饲养的 ASAL 注射鱼时，我们仅在 6HPI 时鉴定了 15 个差异表达基因，在 24HPI 时鉴定了 2 个（FDR 1%）。相比之下，用 pIC 注射鱼进行相同的比较，在 6HPI 和 24HPI 时分别产生了 290 个和 339 个差异表达基因（FDR 1%）。这些结果表明，中度高温对大西洋鳕鱼脾脏对 ASAL（即抗菌反应）的转录组反应的影响小于对 pIC（即抗病毒反应）的影响。因此，高温对鳕鱼免疫反应的影响可能取决于病原体。
