Comparative Transcriptomics in Atlantic Salmon Head Kidney and SHK-1 Cell Line Exposed to the Sea Louse Cr-Cathepsin

Abstract

The development of vaccines against sea lice in salmon farming is complex, expensive, and takes several years for commercial availability. Recently, transcriptome studies in sea louse have provided valuable information for identifying relevant molecules with potential use for fish vaccines. However, the bottleneck is the in vivo testing of recombinant protein candidates, the dosage, and the polyvalent formulation strategies. This study explored a cell-based approach to prospect antigens as candidate vaccines against sea lice by comparison with immunized fish. Herein, SHK-1 cells and Atlantic salmon head kidney tissue were exposed to the antigen cathepsin identified from the sea louse Caligus rogercresseyi. The cathepsin protein was cloned and recombinantly expressed in Escherichia coli, and then SHK-1 cell lines were stimulated with 100 ng/mL cathepsin recombinant for 24 h. In addition, Atlantic salmons were vaccinated with 30 ug/mL recombinant protein, and head kidney samples were then collected 30 days post-immunization. SHK-1 cells and salmon head kidney exposed to cathepsin were analyzed by Illumina RNA sequencing. The statistical comparisons showed differences in the transcriptomic profiles between SHK-1 cells and the salmon head kidney. However, 24.15% of the differentially expressed genes were shared. Moreover, putative gene regulation through lncRNAs revealed tissue-specific transcription patterns. The top 50 up and downregulated lncRNAs were highly correlated with genes involved in immune response, iron homeostasis, pro-inflammatory cytokines, and apoptosis. Also, highly enriched pathways related to the immune system and signal transduction were shared between both tissues. These findings highlight a novel approach to evaluating candidate antigens for sea lice vaccine development, improving the antigens screening in the SHK-1 cell line model.

Effect of CRISPR/Cas9 Targets Associated with Iron Metabolism and Its Variation on Transcriptional Regulation of SHK-1 Cell Line as a Model for Iron Metabolism

“…Fish cell lines have been widely used for the study of biology and disease in salmon [20]. One of the most useful cell lines used in salmon for immunological studies is SHK-1, which has contributed to the study of viruses [21], bacteria [22], parasites [23], and iron metabolism [24], among others. This cell line has proven to be useful to better understand the host-pathogen interaction between salmon and the infectious salmon anemia virus (ISAv) [25].…”

Transcriptome Analysis Revealed Potential Immune-Related Genes of Head Kidney in the Yellow Catfish (Pelteobagrus fulvidraco) Challenged with Aeromonas hydrophila

“…It contains cytokine-producing immune system cells and endocrine cells that release cortisol, catecholamines, and thyroid hormones [14,15]. These immune cells from the head kidney of fishes are involved in recognizing and eliminating pathogens, as well as regulating immune responses [16,17]. The macrophages and neutrophils found in the head kidney of teleost fish are responsible for engulfing and destroying invading pathogens [18].…”