Table_1_Transcriptome Profiling of Atlantic Salmon Adherent Head Kidney Leukocytes Reveals That Macrophages Are Selectively Enriched During Culture.xlsx

The Atlantic salmon (Salmo salar) is an economically important fish, both in aquaculture and in the wild. In vertebrates, macrophages are some of the first cell types to respond to pathogen infection and disease. While macrophage biology has been characterized in mammals, less is known in fish. Our previous work identified changes in the morphology, phagocytic ability, and miRNA profile of Atlantic salmon adherent head kidney leukocytes (HKLs) from predominantly “monocyte-like” at Day 1 of in vitro culture to predominantly “macrophage-like” at Day 5 of culture. Therefore, to further characterize these two cell populations, we examined the mRNA transcriptome profile in Day 1 and Day 5 HKLs using a 44K oligonucleotide microarray. Large changes in the transcriptome were revealed, including changes in the expression of macrophage and immune-related transcripts (e.g. csf1r, arg1, tnfa, mx2), lipid-related transcripts (e.g. fasn, dhcr7, fabp6), and transcription factors involved in macrophage differentiation and function (e.g. klf2, klf9, irf7, irf8, stat1). The in silico target prediction analysis of differentially expressed genes (DEGs) using miRNAs known to change expression in Day 5 HKLs, followed by gene pathway enrichment analysis, supported that these miRNAs may be involved in macrophage maturation by targeting specific DEGs. Elucidating how immune cells, such as macrophages, develop and function is a key step in understanding the Atlantic salmon immune system. Overall, the results indicate that, without the addition of exogenous factors, the adherent HKL cell population differentiates in vitro to become macrophage-like.

大西洋鲑鱼（Salmo salar）作为一种经济价值重大的鱼类，其在水产养殖和野生环境中的重要性不言而喻。在脊椎动物中，巨噬细胞是响应病原体感染和疾病的第一批细胞类型之一。尽管巨噬细胞生物学已在哺乳动物中得到充分研究，但在鱼类中的研究则相对较少。我们先前的研究揭示了从体外培养第1天以“单核细胞样”为主的 Atlantic salmon 附着性头肾白细胞（HKLs）到第5天以“巨噬细胞样”为主的形态、吞噬能力和miRNA谱的变化。因此，为了进一步表征这两种细胞群体，我们采用44K寡核苷酸微阵列，对第1天和第5天的HKLs中的mRNA转录组进行了分析。转录组发生了显著变化，包括巨噬细胞和免疫相关转录物（例如csf1r、arg1、tnfa、mx2）的表达变化，脂质相关转录物（例如fasn、dhcr7、fabp6）的变化，以及参与巨噬细胞分化和功能的转录因子（例如klf2、klf9、irf7、irf8、stat1）的变化。利用已知在第5天HKLs中表达变化的miRNAs对差异表达基因（DEGs）进行计算机模拟靶标预测分析，随后进行基因通路富集分析，支持这些miRNAs可能通过靶向特定的DEGs参与巨噬细胞的成熟。阐明免疫细胞，如巨噬细胞，如何发育和功能，是理解大西洋鲑鱼免疫系统的一个关键步骤。总体而言，结果表明，在未添加外源性因素的情况下，附着性HKL细胞群体在体外分化为巨噬细胞样。