Project description:Immune responses in higher vertebrates are classically separated into innate and adaptive (or specific) immunity. However, important gaps of knowledge about how adaptive responses are generated in lower vertebrates still remain unsolved. In order to explore the relative importance of adaptive and innate immune responses, we have studied zebrafish transcriptional responses to an infection with the Spring Viraemia of Carp virus (SVCV) in rag1-/- zebrafish mutants compared to wild type zebrafish by using both genome wide and immunological-targeted gene expression microarrays. Both wild type (wt) and mutant (rag1) zebrafish were divided in two groups with 3 individuals per group. First group was infected with 10^5 pfu per ml of SVCV, second group was mock-infected. Two days after challenge zebrafish were sampled, head kidney and spleen of each fish were extracted and pooled between each group. The experiment was repeated once to obtain two biological replicates.
Project description:Immune responses in higher vertebrates are classically separated into innate and adaptive (or specific) immunity. However, important gaps of knowledge about how adaptive responses are generated in lower vertebrates still remain unsolved. In order to explore the relative importance of adaptive and innate immune responses, we have studied zebrafish transcriptional responses to an infection with the Spring Viraemia of Carp virus (SVCV) in rag1-/- zebrafish mutants compared to wild type zebrafish by using both genome wide and immunological-targeted gene expression microarrays.
Project description:In the last years, the innate immune response has gained importance since evidences indicate that, after an adequate priming protocol, it is possible to obtain some prolonged and enhanced immune response. Nevertheless, several factors, such as timing and method of administration of the immunostimulants need to be carefully considered. An inappropriate protocol can transform the treatments into a double-edged sword for the teleost immune system, resulting in a stressful and immunosuppressive status. In this work, we analyzed the long-term effect of different stimuli (β-glucans, lipopolysaccharide and Polyinosinic:polycytidylic acid) on the transcriptome modulation induced by Spring Viraemia Carp Virus (SVCV) in adult zebrafish (Danio rerio) and on the mortalities caused by this infection. At 35 days post-immunostimulation the transcriptome was found to be highly altered compared to the control fish, and these stimuli also conditioned the response to SVCV challenge, especially in the case of β-glucans. No protection against SVCV was found with any of the stimuli and even non-significant higher mortalities were observed, especially with β-glucans. However, at short-term (a pre-stimulation with β-glucan and infection after 7 days) a slight protection was observed after infection. The transcriptome response in zebrafish kidney at 35 days post-treatment with β-glucans revealed a significant response associated to stress and immunosuppression. The identification of genes differentially expressed before and after the infection seem to indicate a high energy cost of the immunostimulation prolonged in time that could explain the lack of protection against the SVCV. The differential response to stress, alterations in the lipid metabolism, the tryptophan-kynurenine pathway and the interferon-gamma signaling seem to be some of the mechanisms involved in this particular response, which means the end of the trained immunity and the beginning of a stressful status characterized by immunosuppression.
Project description:Because fin base is supposed to be the entry zone of some fish virus, we wanted to know which transcripts are induced after infection of zebrafish with Spring Viremia Carp Virus (SVCV). Two days after infection, differentially expressed transcript levels from selected immune-related zebrafish genes were studied in zebrafish fins. Also transcripts from resistant fishes to viral infection one month after inoculation were studied.
Project description:The hypoxia signaling pathway controls hypoxia adaptation and tolerance of organisms, which is regulated by multiple mechanisms. Viral infection elicits various pathophysiological responses in the host. However, whether viral infection can affect the hypoxia response is still largely unknown. In this study, we found that Spring viraemia of carp virus (SVCV) infection in zebrafish caused symptoms similar to those in zebrafish under hypoxic conditions. Further assays indicated that SVCV infection activated the hypoxia signaling pathway in zebrafish. In addition, SVCV infection caused increased glycolysis and ROS levels in cells. Mechanistically, SVCV-G protein interacted with hif1α-a/b and attenuated their K48-linked polyubiquitination, leading to their stabilization and subsequent enhancement of target gene expression. Moreover, treatment with the HIF1α-specific inhibitor PX478 enhanced the antiviral ability against SVCV infection in zebrafish and zebrafish cells. This study reveals a relationship between SVCV infection and the hypoxia signaling pathway in fish, and provides a strategy for reducing the damage of viral disease in the aquaculture industry.