RESUMO
Piscirickettsiosis is the most important bacterial disease in the Chilean salmon industry, which has borne major economic losses due to failure to control it. Cells use extracellular vesicles (EVs) as an inter-cellular communicators to deliver several factors (e.g., microRNAs) that may regulate the responses of other cells. However, there is limited knowledge about the identification and characterization of EV-miRNAs in salmonids or the effect of infections on these. In this study, Illumina sequencing technology was used to identify Coho salmon plasma EV-miRNAs upon Piscirickettsia salmonis infection at four different time points. A total of 118 novels and 188 known EV-miRNAs, including key immune teleost miRNAs families (e.g., miR-146, miR-122), were identified. A total of 245 EV-miRNAs were detected as differentially expressed (FDR < 5%) in terms of control, with a clear down-regulation pattern throughout the disease. KEGG enrichment results of EV-miRNAs target genes showed that they were grouped mainly in cellular, stress, inflammation and immune responses. Therefore, it is hypothesized that P. salmonis could potentially benefit from unbalanced modulation response of Coho salmon EV-miRNAs in order to promote a hyper-inflammatory and compromised immune response through the suppression of different key immune host miRNAs during the course of the infection, as indicated by the results of this study.
Assuntos
Doenças dos Peixes/microbiologia , MicroRNAs/metabolismo , Oncorhynchus kisutch/metabolismo , Infecções por Piscirickettsiaceae/imunologia , Animais , Vesículas Extracelulares/metabolismo , Doenças dos Peixes/imunologia , Regulação da Expressão Gênica , Inflamação , Oncorhynchus kisutch/genética , Oncorhynchus kisutch/imunologia , Piscirickettsia/fisiologiaRESUMO
Piscirickettsiosis is the most important bacterial disease in the Chilean salmon industry, which has sorted several efforts to its control, generating enormous economic losses. Epigenetic alterations, such as DNA methylation, can play a relevant role in the modulation of the metazoans response to pathogens. Bacterial disease may activate global and local immune responses generating intricate responses with significant biological impact in the host. However, it is scarcely understood how bacterial infections influence fish epigenetic alterations. In the present study, we utilized Pacific salmon and Piscirickettsiosis as model, to gain understanding into the dynamics of DNA methylation among fish-bacterial infection interactions. A genome-wide analysis of DNA methylation patterns in female spleen tissue of Pacific salmon was achieved by reduced representation bisulphite sequencing from a time course design. We determined 2,251, 1,918, and 2,516 differentially methylated regions DMRs among infected and control Pacific salmon in 1 dpi, 5 dpi, and 15 dpi, respectively. The mean methylation difference per DMR among control and infected groups was of ~35%, with an oscillatory pattern of hypo, hyper, and hypomethylation across the disease. DMCs, among the control and infected group, showed that they were statistically enriched in intergenic regions and depleted in exons. Functional annotation of the DMR genes demonstrated three KEGG principal categories, associated directly with the host response to pathogens infections. Our results provide the first evidence of epigenetic variation in fish provoked by bacterial infection and demonstrate that this variation can be modulated across the disease.
Assuntos
Doenças dos Peixes , Piscirickettsia , Animais , Metilação de DNA , Feminino , SalmãoRESUMO
Patagonian toohfish (Dissostichus eleginoides), is a sub Antartic notothenioid fish key in the marine ecosystem that sustains fishery of higher commercial value in the world. However, there are a scarce knowledge or information about its population genetic background, product of the almost null information of molecular markers available for this species. Here, we use high-throughput sequencing technology (Illumina platform) to develop 1071 microsatellite loci, of which 22 loci were selected to evaluation. Polymorphism and genetic diversity of each locus was assessed in two locations distant by 2370 km. Considering both locations, a mean PIC value of 0.748 was estimated. Selected microsatellite loci showed among two to seventeen alleles by locus in the first location and two to twelve in the second. The observed heterozygosity varied from 0.18 to 0.91 and from 0.12 to 0.87 for the first and second location, respectively. While, the expected heterozygosity ranged from 0.15 to 0.92 and from 0.11 to 0.90. Three loci were monomorphic in only one location. Microsatellite markers developed here will be useful in future studies on conservation, fishery and population genetics of this species.