Acyl-coenzyme A oxidases 1 and 3 in brown trout (Salmo trutta f. fario): Can peroxisomal fatty acid β-oxidation be regulated by estrogen signaling?
Acyl-coenzyme A oxidases 1 (Acox1) and 3 (Acox3) are key enzymes in the regulation of lipid homeostasis. Endogenous and exogenous factors can disrupt their normal expression/activity. This study presents for the first time the isolation and characterization of Acox1 and Acox3 in brown trout (Salmo trutta f. fario). Additionally, as previous data point to the existence of a cross-talk between two nuclear receptors, namely peroxisome proliferator-activated receptors and estrogen receptors, it was here evaluated after in vitro exposures of trout hepatocytes the interference caused by ethynylestradiol in the mRNA levels of an inducible (by peroxisome proliferators) and a non-inducible oxidase. The isolated Acox1 and Acox3 show high levels of sequence conservation compared to those of other teleosts. Additionally, it was found that Acox1 has two alternative splicing isoforms, corresponding to 3I and 3II isoforms of exon 3 splicing variants. Both isoforms display tissue specificity, with Acox1-3II presenting a more ubiquitous expression in comparison with Acox1-3I. Acox3 was expressed in almost all brown trout tissues. According to real-time PCR data, the highest estrogenic stimulus was able to cause a down-regulation of Acox1 and an up-regulation of Acox3. So, for Acox1 we found a negative association between an estrogenic input and a directly activated PPARα target gene. In conclusion, changes in hormonal estrogenic stimulus may impact the mobilization of hepatic lipids to the gonads, with ultimate consequences in reproduction. Further studies using in vivo assays will be fundamental to clarify these issues.
CIIMAR - Interdisciplinary Centre of Marine and Environmental Research, U.Porto - University of Porto, Rua dos Bragas 289, 4050-123, Porto, Portugal. tvmadureira@icbas.up.pt.|Laboratory of Histology and Embryology, Department of Microscopy, ICBAS - Institute of Biomedical Sciences Abel Salazar, U.Porto - University of Porto, Rua Jorge Viterbo Ferreira 228, 4050-313, Porto, Portugal. tvmadureira@icbas.up.pt.
Tânia Vieira
TV
Madureira
CIIMAR - Interdisciplinary Centre of Marine and Environmental Research, U.Porto - University of Porto, Rua dos Bragas 289, 4050-123, Porto, Portugal.|Department of Biology, FCUP - Faculty of Sciences, U.Porto - University of Porto, Rua do Campo Alegre, 4169-007, Porto, Portugal.
L Filipe C
LF
Castro
CIIMAR - Interdisciplinary Centre of Marine and Environmental Research, U.Porto - University of Porto, Rua dos Bragas 289, 4050-123, Porto, Portugal.|Laboratory of Histology and Embryology, Department of Microscopy, ICBAS - Institute of Biomedical Sciences Abel Salazar, U.Porto - University of Porto, Rua Jorge Viterbo Ferreira 228, 4050-313, Porto, Portugal.
Eduardo
E
Rocha
D042962:Acyl-CoA Oxidase / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D018076:DNA, Complementary / Q000235:genetics; D004967:Estrogens / Q000494:pharmacology*; D004997:Ethinyl Estradiol / Q000494:pharmacology*; D029941:Fish Proteins / Q000235:genetics*; D005786:Gene Expression Regulation / Q000187:drug effects; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D047493:PPAR alpha / Q000235:genetics; D010802:Phylogeny; D012333:RNA, Messenger / Q000378:metabolism; D014337:Trout / Q000235:genetics*
D018076:DNA, Complementary; D004967:Estrogens; D029941:Fish Proteins; D047493:PPAR alpha; D012333:RNA, Messenger; D004997:Ethinyl Estradiol; D042962:Acyl-CoA Oxidase
Acox1; Acox3; Brown trout; Estrogens; PPARs