Examining host-pathogen interactions at mucosal surfaces reveals novel molecular targets for columnaris disease intervention

Authors: Beck, Benjamin; PEATMAN, ERIC - Auburn University

Submitted to: Proceedings of the United States Japan Natural Resource Aquaculture Panel
Publication Type: Proceedings
Publication Acceptance Date: 4/27/2015
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Columnaris disease, caused by the bacterial pathogen Flavobacterium columnare, is a major problem globally and leads to tremendous losses of freshwater fish, particularly in intensively farmed aquaculture species. Despite its widespread importance, our understanding of F. columnare infectious processes remains limited. Specifically, little is known regarding the mechanisms controlling pathogen adhesion and replication on host mucosal surfaces. Utilizing next-generation sequencing-based RNA-seq we profiled the transcriptome in columnaris disease resistant and susceptible families of channel catfish, to examine transcriptional differences in mucosal barriers (e.g, skin and gill) before pathogen exposure and at early timepoints following a columnaris challenge. The results revealed a consistent pattern of basal immune polarization between resistant and susceptible fish prior to challenge, including key differences in expression of genes linked to mucin abundance and composition, lysozyme, and a rhamnose-binding lectin; a potential receptor for F. columnare. Next, we profiled the transcriptome of mucosal tissues of channel catfish under conditions of routine feeding versus short-term feed deprivation. Surprisingly, we found numerous shared mucosal gene expression signatures between resistant/fed fish and susceptible/fasted fish. The position of these molecular actors on ectopic mucosal surfaces could make them accessible for use as prognostic indicators of disease fitness, and highly amenable to modulation through dietary or topical prophylactic or therapeutant approaches.