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Estrogen modulates hepatic gene expression and survival of rainbow trout infected with pathogenic bacteria Yersinia ruckeri.

ABSTRACT: Juvenile rainbow trout were exposed to two different concentrations of 17β-estradiol (E2) (2 or 20 mg/kg feed), and then infected with three concentrations of Yersinia ruckeri, a bacterial pathogen causing massive losses in wild and farmed salmonid populations. Infection with Y. ruckeri caused mortality of trout, and this effect was significantly enhanced by simultaneous exposure to high E2 dose. Analysis of hepatic gene expression profiles revealed complex regulations of pathways involved in immune responses, stress responses and detoxicification pathways. E2 markedly reduced expression of several genes implicated in xenobiotic metabolism. The results suggest that the interaction between pathogen and E2 interfered with the fish’s capability of clearing toxic compounds. The findings of the current study add to our understanding of multiple exposure responses in fish.

ORGANISM(S): Oncorhynchus mykiss

PROVIDER: GSE38763 | GEO | 2012/06/17

SECONDARY ACCESSION(S): PRJNA168566

REPOSITORIES: GEO

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Project description:Whirling disease, caused by the pathogen Myxobolus cerebralis, afflicts several salmonid species. Rainbow trout are particularly susceptible and suffer high mortality rates. The disease is persistent and spreading in hatcheries and natural waters of several countries, including the U.S., and the economic losses associated with whirling disease have been extremely large. In this study, gene expression profiling was conducted for resistant and susceptible rainbow trout strains following pathogen exposure with the primary objective of identifying specific genes associated with whirling disease resistance. Several genes were significantly up-regulated in skin following pathogen exposure for both the resistant Hofer and susceptible Trout Lodge rainbow trout strains. For both strains, response to infection appears to be associated with the interferon system. Metallothionein is differentially expressed between the resistant and susceptible strains and is a good candidate for future studies due to its diverse functional roles in inflammation and immune response. The present study has provided the first examination into the genetic basis underlying rainbow trout’s immune response and resistance to the whirling disease pathogen. The identified genes have allowed us to gain initial insight into the molecular mechanisms associated with a salmonid host’s immune response and resistance to whirling disease infection. Keywords: Disease state comparison. 1st comparison: exposed vs control. 2nd comparison: resistant vs susceptible strains Resistant (Hofer) and susceptible (Trout Lodge) rainbow trout strains were exposed to 2,000 triactinomyxons (whirling disease pathogen) per fish. Unexposed controls for each strain were treated identically to exposed other than their lack of pathogen exposure. After twenty-four hours, caudal fin tissue was collected for RNA extraction. Amplified RNA was competitively hybridized (exposed versus control) for each strain. Four biological replicates were used for each experimental condition and a balanced block design was incorporated.

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Estrogen modulates hepatic gene expression and survival of rainbow trout infected with pathogenic bacteria Yersinia ruckeri.

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