Contributors: Laboratoire de Physiologie et Génomique des Poissons = Fish Physiology and Genomics Institute (LPGP); Structure Fédérative de Recherche en Biologie et Santé de Rennes (Biosit : Biologie - Santé - Innovation Technologique)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE); Expertise en Anatomie Pathologique (APEX); Physiopathologie Animale et bioThérapie du muscle et du système nerveux (PAnTher); École nationale vétérinaire, agroalimentaire et de l'alimentation Nantes-Atlantique (ONIRIS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-École nationale vétérinaire, agroalimentaire et de l'alimentation Nantes-Atlantique (ONIRIS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE); Dynamiques de populations multi-échelles pour des systèmes physiologiques / MUltiSCAle population dynamics for physiological systems (MUSCA); Mathématiques et Informatique Appliquées du Génome à l'Environnement Jouy-En-Josas (MaIAGE); Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Physiologie de la reproduction et des comportements Nouzilly (PRC); Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre Inria de l'Université Paris-Saclay; Centre Inria de Saclay; Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre Inria de Saclay; Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria); IT BCDE; ANR-22-CE45-0017,OVOPAUSE,Dynamique et contrôle des populations de cellules germinales femelles : comprendre le vieillissement à travers des modèles de dynamique des populations(2022)
Abstract: International audience ; In teleost fish, female fecundity depends essentially on the oocyte reserve, which determines the number of eggs laid in each reproductive cycle. Unlike mammals, which have a limited and predefined stock of oocytes at birth, this reserve can be renewed throughout female's life. In adult teleost, this reserve is, on the one hand, used to generate mature oocytes ready to be laid and, on the other hand, replenished from germline stem cells present in specialized structures called germline cradles. A main issue is to understand the contribution of these germline stem cells in the renewal of the oocyte reserve in both juveniles and adults, as well as the involved regulatory mechanisms.To this end, we have implemented a 3D whole ovary imaging strategy in Medaka to provide quantitative data and study the cellular dynamics of the germinal cradle. We have refined ovary clearing protocols combined with immunolabelings (e.g., anti-vasa, anti-pH3, anti-GFP), and imaged the ovaries using light sheet microscopy. In addition, we have set up 3D image analysis pipelines that integrates pre-trained open-source neural networks suitable for precise segmentation. These deep-learning based pipelines have greatly improved our ability to manage complex 3D analysis of the germinal cradle and allow us to access quantitative data at the level of the entire ovary. We are now analyzing the number, the distribution and the composition of germinal cradles in wild-type females, as well as in two KO lines (miR-202 -/- and miR-187 -/-) showing a drastic decrease in female fecundity, to uncover the miRNA-mediated regulatory mechanisms. In the future, this approach should also provide us with the means to explore in depth the interactions between the somatic and germ cells within germinal cradles, including their spatial organisation.
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