%0 Journal Article %J Frontiers in Ecology and Evolution %D 2021 %T Interdependence of thyroid and corticosteroid signalling in vertebrate developmental transitions %A Karine Rousseau %A Sylvie Dufour %A Sachs, Laurent M %B Frontiers in Ecology and Evolution %V 9 %P 735487 %G eng %R 10.3389/fevo.2021.735487 %0 Book Section %B The Physiology of Fishes, Fifth Edition %D 2020 %T Endocrinology: An evolutionary perspective on neuroendocrine axes in teleosts %A Sylvie Dufour %A Karine Rousseau %B The Physiology of Fishes, Fifth Edition %7 Suzanne Curie and David H. Evans, Editors %I CRC Press, Taylor & Francis Group %C Boca Raton,FL %P 105-116 %G eng %& 8 %R 10.1201/9781003036401 %0 Journal Article %J Frontiers in Endocrinology %D 2018 %T Eel Kisspeptins: identification, functional activity, and inhibition on both pituitary LH and GnRH receptor expression %A Pasquier, J %A Anne-Gaelle Lafont %A Florian, D %A Lefranc, B %A Dubessy, C %A Moreno-Herrera, A %A Vaudry, H %A Leprince, J %A Sylvie Dufour %A Karine Rousseau %X

The European eel (Anguilla anguilla) presents a blockade of sexual maturation at a prepubertal stage due to a deficient production of gonadotropins. We previously initiated, in the eel, the investigation of the kisspeptin system, one of the major gatekeepers of puberty in mammals, and we predicted the sequence of two Kiss genes. In the present study, we cloned and sequenced Kiss1 and Kiss2 cDNAs from the eel brain. The tissue distributions of Kiss1 and Kiss2 transcripts, as investigated by quantitative real-time PCR, showed that both genes are primarily expressed in the eel brain and pituitary. The two 10-residue long sequences characteristic of kisspeptin, eel Kp1(10) and Kp2(10), as well as two longer sequences, predicted as mature peptides, eel Kp1(15) and Kp2(12), were synthesized and functionally analyzed. Using rat Kiss1 receptor-transfected Chinese hamster ovary cells, we found that the four synthesized eel peptides were able to induce [Ca2+]i responses, indicating their ability to bind mammalian KissR-1 and to activate second messenger pathways. In primary culture of eel pituitary cells, all four peptides were able to specifically and dose-dependently inhibit lhβ expression, without any effect on fshβ, confirming our previous data with heterologous kisspeptins. Furthermore, in this eel in vitro system, all four peptides inhibited the expression of the type 2 GnRH receptor (gnrh-r2). Our data revealed a dual inhibitory effect of homologous kisspeptins on both pituitary lhβ and gnrh-r2 expression in the European eel.

%B Frontiers in Endocrinology %V 8 %P 353 %G eng %R 10.3389/fendo.2017.00353 %0 Journal Article %J Frontiers in Endocrinology %D 2018 %T Tachykinin-3 Genes and Peptides Characterized in a Basal Teleost, the European Eel: Evolutionary Perspective and Pituitary Role. %A Campo, Aurora %A Anne-Gaelle Lafont %A Lefranc, Benjamin %A Leprince, Jérôme %A Tostivint, Hervé %A Kamech, Nedia %A Sylvie Dufour %A Karine Rousseau %B Frontiers in Endocrinology %V 9 %P 304 %G eng %0 Journal Article %J J Neuroendocrinol %D 2016 %T Functional characterization of eel dopamine D2 receptors and involvement in the direct inhibition of pituitary gonadotropins. %A Jolly, C %A Karine Rousseau %A Prézeau, L %A Vol, C %A Tomkiewicz, J %A Sylvie Dufour %A Pasqualini, C %X

In various vertebrate species, dopamine (DA) exerts an inhibitory action on reproduction. In the European eel, DA plays a pivotal role in the inhibitory control of the gonadotrope function and the blockade of puberty. In vivo studies suggested that this effect is mediated by receptors pharmacologically related to the D2-family. In the European eel, two distinct D2 receptor (D2-R) paralogous genes have been identified (D2A-R and D2B-R) and both shown to be expressed in the pituitary. We investigated the potential role of each paralog in the control of gonadotrope function in this species. Eel recombinant D2A-R or D2B-R were expressed in HEK 293 cells, with a universal Gα subunit, and receptor activation was followed by inositol phosphate production. Recombinant D2-Rs exhibited a comparable affinity for DA, but differential affinities for mammalian D2-R agonists and antagonists, supporting subtle structure/activity differences. Further, using eel pituitary cell primary cultures, the expression by gonadotrope cells of both native eel D2-R paralogs was examined by in situ hybridisation of D2A-R or D2B-R transcripts, coupled to immunofluorescence of LHβ or FSHβ. LH and to a lesser extent, FSH cells expressed both D2-R transcripts, but with a clear predominance of D2B-R. Notably, D2B- R transcripts were detected on the majority of LH cells. Accordingly, using these cultures, we showed that DA potently inhibited basal and testosterone-stimulated LHβ expression and less potently basal and activin-stimulated FSHβ expression. We also tested some D2-R antagonists in order to select the most adequate one to be used in innovative protocols for induction of eel sexual maturation. We identified eticlopride as the most potent inhibitor of DA action on basal and stimulated LH expression in vitro. Our data suggest a differential functionalisation of the duplicated receptor genes and demonstrate that mainly D2B-R is involved in the dopaminergic inhibitory control of eel gonadotrope function. This article is protected by copyright. All rights reserved.

%B J Neuroendocrinol %8 2016 Jul 25 %G eng %R 10.1111/jne.12411 %0 Journal Article %J Gen Comp Endocrinol %D 2016 %T Three nuclear and two membrane estrogen receptors in basal teleosts, Anguilla sp.: Identification, evolutionary history and differential expression regulation. %A Anne-Gaelle Lafont %A Karine Rousseau %A Tomkiewicz, Jonna %A Sylvie Dufour %X

Estrogens interact with classical intracellular nuclear receptors (ESR), and with G-coupled membrane receptors (GPER). In the eel, we identified three nuclear (ESR1, ESR2a, ESR2b) and two membrane (GPERa, GPERb) estrogen receptors. Duplicated ESR2 and GPER were also retrieved in most extant teleosts. Phylogeny and synteny analyses suggest that they result from teleost whole genome duplication (3R). In contrast to conserved 3R-duplicated ESR2 and GPER, one of 3R-duplicated ESR1 has been lost shortly after teleost emergence. Quantitative PCRs revealed that the five receptors are all widely expressed in the eel, but with differential patterns of tissue expression and regulation. ESR1 only is consistently up-regulated in vivo in female eel BPG-liver axis during induced sexual maturation, and also up-regulated in vitro by estradiol in eel hepatocyte primary cultures. This first comparative study of the five teleost estradiol receptors provides bases for future investigations on differential roles that may have contributed to the conservation of multiple estrogen receptors.

%B Gen Comp Endocrinol %V 235 %P 177-91 %8 2016 Sep 1 %G eng %R 10.1016/j.ygcen.2015.11.021 %0 Journal Article %J PLoS One %D 2015 %T Duplicated leptin receptors in two species of eel bring new insights into the evolution of the leptin system in vertebrates. %A Morini, Marina %A Pasquier, Jérémy %A Dirks, Ron %A van den Thillart, Guido %A Tomkiewicz, Jonna %A Karine Rousseau %A Sylvie Dufour %A Anne-Gaelle Lafont %X

Since its discovery in mammals as a key-hormone in reproduction and metabolism, leptin has been identified in an increasing number of tetrapods and teleosts. Tetrapods possess only one leptin gene, while most teleosts possess two leptin genes, as a result of the teleost third whole genome duplication event (3R). Leptin acts through a specific receptor (LEPR). In the European and Japanese eels, we identified two leptin genes, and for the first time in vertebrates, two LEPR genes. Synteny analyses indicated that eel LEPRa and LEPRb result from teleost 3R. LEPRb seems to have been lost in the teleost lineage shortly after the elopomorph divergence. Quantitative PCRs revealed a wide distribution of leptins and LEPRs in the European eel, including tissues involved in metabolism and reproduction. Noticeably, leptin1 was expressed in fat tissue, while leptin2 in the liver, reflecting subfunctionalization. Four-month fasting had no impact on the expression of leptins and LEPRs in control European eels. This might be related to the remarkable adaptation of silver eel metabolism to long-term fasting throughout the reproductive oceanic migration. In contrast, sexual maturation induced differential increases in the expression of leptins and LEPRs in the BPG-liver axis. Leptin2 was strikingly upregulated in the liver, the central organ of the reproductive metabolic challenge in teleosts. LEPRs were differentially regulated during sexual maturation, which may have contributed to the conservation of the duplicated LEPRs in this species. This suggests an ancient and positive role of the leptin system in the vertebrate reproductive function. This study brings new insights on the evolutionary history of the leptin system in vertebrates. Among extant vertebrates, the eel represents a unique case of duplicated leptins and leptin receptors as a result of 3R.

%B PLoS One %V 10 %P e0126008 %8 2015 %G eng %N 5 %R 10.1371/journal.pone.0126008 %0 Journal Article %J Front Endocrinol (Lausanne) %D 2015 %T Editorial: A Comparative Survey of the RF-Amide Peptide Superfamily. %A Karine Rousseau %A Sylvie Dufour %A Vaudry, Hubert %B Front Endocrinol (Lausanne) %V 6 %P 120 %8 2015 %G eng %R 10.3389/fendo.2015.00120 %0 Journal Article %J BMC Evol Biol %D 2014 %T Looking for the bird Kiss: evolutionary scenario in sauropsids. %A Pasquier, Jérémy %A Anne-Gaelle Lafont %A Karine Rousseau %A Quérat, Bruno %A Chemineau, Philippe %A Sylvie Dufour %K Amino Acid Sequence %K Animals %K Avian Proteins %K Biological Evolution %K Birds %K Humans %K Kisspeptins %K Molecular Sequence Data %K Phylogeny %K Receptors, G-Protein-Coupled %K Reptiles %K Sequence Alignment %K Synteny %X

BACKGROUND: The neuropeptide Kiss and its receptor KissR are key-actors in the brain control of reproduction in mammals, where they are responsible for the stimulation of the activity of GnRH neurones. Investigation in other vertebrates revealed up to 3 Kiss and 4 KissR paralogs, originating from the two rounds of whole genome duplication in early vertebrates. In contrast, the absence of Kiss and KissR has been suggested in birds, as no homologs of these genes could be found in current genomic databases. This study aims at addressing the question of the existence, from an evolutionary perspective, of the Kisspeptin system in birds. It provides the first large-scale investigation of the Kisspeptin system in the sauropsid lineage, including ophidian, chelonian, crocodilian, and avian lineages.

RESULTS: Sauropsid Kiss and KissR genes were predicted from multiple genome and transcriptome databases by TBLASTN. Phylogenetic and syntenic analyses were performed to classify predicted sauropsid Kiss and KissR genes and to re-construct the evolutionary scenarios of both gene families across the sauropsid radiation.Genome search, phylogenetic and synteny analyses, demonstrated the presence of two Kiss genes (Kiss1 and Kiss2 types) and of two KissR genes (KissR1 and KissR4 types) in the sauropsid lineage. These four genes, also present in the mammalian lineage, would have been inherited from their common amniote ancestor. In contrast, synteny analyses supported that the other Kiss and KissR paralogs are missing in sauropsids as in mammals, indicating their absence in the amniote lineage. Among sauropsids, in the avian lineage, we demonstrated the existence of a Kiss2-like gene in three bird genomes. The divergence of these avian Kiss2-like sequences from those of other vertebrates, as well as their absence in the genomes of some other birds, revealed the processes of Kiss2 gene degeneration and loss in the avian lineage.

CONCLUSION: These findings contribute to trace back the evolutionary history of the Kisspeptin system in amniotes and sauropsids, and provide the first molecular evidence of the existence and fate of a Kiss gene in birds.

%B BMC Evol Biol %V 14 %P 30 %8 2014 %G eng %N 1 %R 10.1186/1471-2148-14-30 %0 Journal Article %J J. Mol. Endocrinol. %D 2014 %T Molecular evolution of GPCRs: Kisspeptin/kisspeptin receptors. %A Pasquier, J %A Kamech, Nedia %A Anne-Gaelle Lafont %A H Vaudry %A Karine Rousseau %A Sylvie Dufour %B J. Mol. Endocrinol. %V 52 %P 101-117 %G eng %N 3