Modulation of innate immune-related genes and glucocorticoid synthesis in gnotobiotic full-sibling European sea bass (Dicentrarchus labrax) larvae challenged with Vibrio anguillarum

• Published in: Frontiers in Immunology
• Main Authors: Reyes-López, Felipe E, Aerts, Johan, Vallejos-Vidal, Eva, Ampe, Bart, Dierckens, Kristof, Tort, Lluis, Bossier, Peter
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2018
• Subjects: Biology and Life Sciences; cytokines; iron regulation; cortisol; gnotobiotic system; European sea bass; fish larvae; Vibrio anguillarum; TROUT ONCORHYNCHUS-MYKISS; ANTIINFLAMMATORY CYTOKINE EXPRESSION; PITUITARY-INTERRENAL AXIS; ACUTE REGULATORY PROTEIN; CARP CYPRINUS-CARPIO; C-REACTIVE PROTEIN; IRON UPTAKE SYSTEM; IGM-BEARING CELLS; GADUS-MORHUA L; RAINBOW-TROUT; Gadus morhua
• Online Access: https://biblio.ugent.be/publication/8589834; http://hdl.handle.net/1854/LU-8589834; https://doi.org/10.3389/fimmu.2018.00914; https://biblio.ugent.be/publication/8589834/file/8589872

Although several efforts have been made to describe the immunoendocrine interaction in fish, there are no studies to date focusing on the characterization of the immune response and glucocorticoid synthesis using the host-pathogen interaction on larval stage as an early developmental stage model of study. Therefore, the aim of this study was to evaluate the glucocorticoid synthesis and the modulation of stress-and innate immune-related genes in European sea bass (Dicentrarchus labrax) larvae challenged with Vibrio anguillarum. For this purpose, we challenged by bath full-sibling gnotobiotic sea bass larvae with 107 CFU mL(-1) of V. anguillarum strain HI 610 on day 5 post-hatching (dph). The mortality was monitored up to the end of the experiment [120 hours post-challenge (hpc)]. While no variations were registered in non-challenged larvae maintained under gnotobiotic conditions (93.20% survival at 120 hpc), in the challenged group a constant and sustained mortality was observed from 36 hpc onward, dropping to 18.31% survival at 120 hpc. Glucocorticoid quantification and expression analysis of stress-and innate immunity-related genes were carried out in single larvae. The increase of cortisol, cortisone and 20 beta-dihydrocortisone was observed at 120 hpc, although did not influence upon the modulation of stress-related genes (glucocorticoid receptor 1 [gr1], gr2, and heat shock protein 70 [hsp70]). On the other hand, the expression of lysozyme, transferrin, and il-10 differentially increased at 120 hpc together with a marked upregulation of the pro-inflammatory cytokines (il-1 beta and il-8) and hepcidin, suggesting a late activation of defense mechanisms against V. anguillarum. Importantly, this response coincided with the lowest survival observed in challenged groups. Therefore, the increase in markers associated with glucocorticoid synthesis together with the upregulation of genes associated with the anti-inflammatory response suggests that in larvae infected with V. anguillarum a pro-inflammatory response at ...