Hyper- and hypo-osmotic challenges modify hormonal pathways in the gilthead sea bream (Sparus aurata): a microarray approach

Trabajo presentado en el 10º Congreso de la Asociación Ibérica de Endocrinología Comparada, celebrado en Castellón del 23 al 25 de septiembre de 2015.Euryhaline teleost can live in a wide range of environmental salinities. This ability is carried out by different osmoregulatory and non-osmoregulatory tissues, being gills, liver and hypothalamus very important due to their implications in ion and water exchange, metabolism and endocrine regulation, respectively. Transcriptomic analysis in these tissues by means of a specific oligo-microarray revealed new aspects related to the osmoregulatory processes mediated by different endocrine pathways after hypo- (38¿ ¿ 5¿) or hyper- (38¿ ¿ 55¿) osmotic challenges to gilthead sea bream juveniles. In liver, aldosterone-related signalling pathways, represented by 8 heat shock proteins (DNAJC8, DNAJC11, DNAJC17, DNAJC30, HSP90AB1, HSPA14, HSPD1 and HSPE1), showed an up-regulation in both salinity challenges, while other enzymes related to cell growth (PRKCA), division (KRAS) and maturation (PIK3C3) were down-regulated. In gills, serotonin, melatonin and thyroid hormone pathways were affected by the differential up-regulation of genes involved in xenobiotic and protective metabolism facing transfer to 5¿ (CYP1A1, SULT1A1 and UGT1A1) or 55¿ (CYP1B1, UGT2A3). A similar pattern was also observed for several genes involved in the melatonin metabolism pathway (CYP2J2, CYP1B1 and SULT1A1) in the hypothalamus of specimens transferred to 5¿, whereas hyperosmotic challenge induced a clear down-regulation in another gene (UGT1A9) involved in xenobiotic metabolism. Taking together, these results point out the importance of liver, gills and hypothalamus in the response to osmolality change, showing the differentially regulated endocrine components and pathways that process the harmful metabolites related to osmotic stress.This research was funded by the Spanish Ministry of Economic Affairs and Competitiveness (MINECO) with FEDER/ERDF contribution by projects AGL2013-48835-C2-1-R to J.M.M. and AQUAGENOMICS (CDS2007-00002) to M.Y and J.P-S.Peer Reviewe