title: Redefining the initiation and maintenance of zebrafish interrenal steroidogenesis by characterizing the key enzyme cyp11a2.
abstract: Zebrafish are emerging as a model to study steroid hormone action and associated disease. However, steroidogenesis in zebrafish is not well characterized. Mammalian P450 side-chain cleavage enzyme (CYP11A1) catalyzes the first step of steroidogenesis, the conversion of cholesterol to pregnenolone. Previous studies describe an essential role for zebrafish Cyp11a1 during early development. Cyp11a1 has been suggested to be the functional equivalent of mammalian CYP11A1 in the zebrafish interrenal gland (equivalent to the mammalian adrenal), gonad, and brain. However, reported cyp11a1 expression is inconsistent in zebrafish larvae, after active cortisol synthesis commences. Recently a duplicated cyp11a gene, cyp11a2, has been described, which shares an 85% identity with cyp11a1. We aimed to elucidate the specific role of the two cyp11a paralogs. cyp11a1 was expressed from 0 to 48 hours post-fertilization (hpf), whereas cyp11a2 expression started after the development of the interrenal primordium (32 hpf) and was the only paralog in larvae. cyp11a2 is expressed in adult steroidogenic tissues, such as the interrenal, gonads, and brain. In contrast, cyp11a1 was mainly restricted to the gonads. Antisense morpholino knockdown studies confirmed abnormal gastrulation in cyp11a1 morphants. cyp11a2 morphants showed impaired steroidogenesis and a phenotype indicative of metabolic abnormalities. The phenotype was rescued by pregnenolone replacement in cyp11a2 morphants. Thus, we conclude that cyp11a1 is required for early development, whereas cyp11a2 is essential for the initiation and maintenance of zebrafish interrenal steroidogenesis. Importantly, this study highlights the need for a comprehensive characterization of steroidogenesis in zebrafish prior to its implementation as a model organism in translational research of adrenal disease.
authors.affiliation: Centre for Endocrinology, Diabetes, and Metabolism, School of Clinical and Experimental Medicine, University of Birmingham, Birmingham B15 2TT, United Kingdom.
authors.forename: Silvia
authors.initials: S
authors.lastname: Parajes
authors.forename: Aliesha
authors.initials: A
authors.lastname: Griffin
authors.forename: Angela E
authors.initials: AE
authors.lastname: Taylor
authors.forename: Ian T
authors.initials: IT
authors.lastname: Rose
authors.forename: Irene
authors.initials: I
authors.lastname: Miguel-Escalada
authors.forename: Yavor
authors.initials: Y
authors.lastname: Hadzhiev
authors.forename: Wiebke
authors.initials: W
authors.lastname: Arlt
authors.forename: Cedric
authors.initials: C
authors.lastname: Shackleton
authors.forename: Ferenc
authors.initials: F
authors.lastname: Müller
authors.forename: Nils
authors.initials: N
authors.lastname: Krone
mesh_terms: D000818:Animals; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000187:drug effects / Q000196:embryology / Q000378:metabolism; D054262:Gastrulation / Q000187:drug effects / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D055785:Gene Knockdown Techniques; D007401:Interrenal Gland / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D007814:Larva / Q000235:genetics / Q000254:growth & development; D010641:Phenotype; D010802:Phylogeny; D011284:Pregnenolone / Q000378:metabolism / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013256:Steroids / Q000096:biosynthesis*; D013997:Time Factors; D015027:Zebrafish / Q000196:embryology / Q000235:genetics* / Q000254:growth & development; D029961:Zebrafish Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D007527:Isoenzymes; D013256:Steroids; D029961:Zebrafish Proteins; D011284:Pregnenolone; D002786:Cholesterol Side-Chain Cleavage Enzyme; C583989:cyp11a2 protein, zebrafish