The transcriptional regulation of Atlantic salmon macrophage like cells SHK 1 infected by P. salmonis is dominated by KLF17 and MAFBA

The Atlantic salmon is the most relevant specie in the Chilean aquaculture. Currently it faces high mortality rates by the infectious disease SRS, caused by the bacterial pathogen P. salmonis. As the current antimicrobial strategies are inefficient, we need to get a better understanding of the Atlantic salmon immune response against this pathogen.Macrophages play the role of starting the immune response by detecting, and processing the pathogen, and its specific transcriptomic response remains unknown. In this work we aim to study the transcriptomic changes on macrophage cell line SHK-1 infected with P. salmonis and improve the use of available databases generating a small database called SalSaDB, which include a predicted reference gene regulatory network (GRN), allowing us to understand the regulatory interactions of this transcriptomic analysis. To analyze the early stage of infection, we analyzed SHK-1 cells infected by P. salmonis at 24 and 48 hours post infection (hpi) by RNAseq.Altogether our results suggest that the macrophage like cell line SHK 1 infected by P. salmonis exhibits an M2 like phenotype, which is a characteristic phenomenon observed in macrophages infected by intracellular pathogens, and it correlates with our previous works, where we observed lysosomal inactivation in early stages of infection. These results are the first time where the available databases of Atlantic salmon were used together to obtain the most of a transcriptomic analysis, involving the use of GRN and a macrophage like cell culture instead of tissue from infected fish to understand the early stages of infection by P. salmonis.