Department of Ocean Sciences, Memorial University of Newfoundland, St. John's, NL, Canada.
Department of Ocean Sciences, Memorial University of Newfoundland, St. John's, NL, Canada.
Fish Shellfish Immunol. 2020 Mar;98:937-949. doi: 10.1016/j.fsi.2019.11.057. Epub 2019 Nov 23.
Renibacterium salmoninarum is a Gram-positive, intracellular bacterial pathogen that causes Bacterial Kidney Disease (BKD) in Atlantic salmon (Salmo salar). The host transcriptomic response to this immune-suppressive pathogen remains poorly understood. To identify R. salmoninarum-responsive genes, Atlantic salmon were intraperitoneally injected with a low (5 × 10 cells/kg, Low-Rs) or high (5 × 10 cells/kg; High-Rs) dose of formalin-killed R. salmoninarum bacterin or phosphate-buffered saline (PBS control); head kidney samples were collected before and 24 h after injection. Using 44K microarray analysis, we identified 107 and 345 differentially expressed probes in response to R. salmoninarum bacterin (i.e. High-Rs vs. PBS control) by Significance Analysis of Microarrays (SAM) and Rank Products (RP), respectively. Twenty-two microarray-identified genes were subjected to qPCR assays, and 17 genes were confirmed as being significantly responsive to the bacterin. There was an up-regulation in expression of genes playing putative roles as immune receptors and antimicrobial effectors. Genes with putative roles as pathogen recognition (e.g. clec12b and tlr5) or immunoregulatory (e.g. tnfrsf6b and tnfrsf11b) receptors were up-regulated in response to R.salmoninarum bacterin. Also, chemokines and a chemokine receptor showed opposite regulation [up-regulation of effectors (i.e. ccl13 and ccl) and down-regulation of cxcr1] in response to the bacterin. The present study identified and validated novel biomarker genes (e.g. ctsl1, lipe, cldn4, ccny) that can be used to assess Atlantic salmon response to R. salmoninarum, and will be valuable in the development of tools to combat BKD.
鲑居尾孢菌是一种革兰氏阳性、细胞内细菌病原体，可引起大西洋鲑（Salmo salar）的细菌性肾病（BKD）。宿主对这种免疫抑制病原体的转录组反应仍知之甚少。为了鉴定对鲑居尾孢菌有反应的基因，将大西洋鲑用低（5×10 个细胞/公斤，低剂量 Rs）或高（5×10 个细胞/公斤；高剂量 Rs）剂量的福尔马林杀死的鲑居尾孢菌菌苗或磷酸盐缓冲盐水（PBS 对照）经腹腔注射；在注射前和注射后 24 小时采集头肾样本。使用 44K 微阵列分析，通过显著性分析微阵列（SAM）和秩乘积（RP），我们分别鉴定出 107 个和 345 个对鲑居尾孢菌菌苗（即高剂量 Rs 与 PBS 对照）有差异表达的探针。对 22 个微阵列鉴定的基因进行 qPCR 检测，其中 17 个基因被证实对菌苗有显著反应。具有免疫受体和抗菌效应物潜在作用的基因表达上调。具有病原体识别（如 clec12b 和 tlr5）或免疫调节（如 tnfrsf6b 和 tnfrsf11b）受体潜在作用的基因在对鲑居尾孢菌菌苗的反应中上调。此外，趋化因子和趋化因子受体表现出相反的调节[效应物（即 ccl13 和 ccl）上调和 cxcr1 下调]对菌苗的反应。本研究鉴定和验证了新的生物标志物基因（如 ctsl1、lipe、cldn4、ccny），可用于评估大西洋鲑对鲑居尾孢菌的反应，这对于开发防治 BKD 的工具将是有价值的。
