title: Loss of neurogenesis in Hydra leads to compensatory regulation of neurogenic and neurotransmission genes in epithelial cells.
abstract: Hydra continuously differentiates a sophisticated nervous system made of mechanosensory cells (nematocytes) and sensory-motor and ganglionic neurons from interstitial stem cells. However, this dynamic adult neurogenesis is dispensable for morphogenesis. Indeed animals depleted of their interstitial stem cells and interstitial progenitors lose their active behaviours but maintain their developmental fitness, and regenerate and bud when force-fed. To characterize the impact of the loss of neurogenesis in Hydra, we first performed transcriptomic profiling at five positions along the body axis. We found neurogenic genes predominantly expressed along the central body column, which contains stem cells and progenitors, and neurotransmission genes predominantly expressed at the extremities, where the nervous system is dense. Next, we performed transcriptomics on animals depleted of their interstitial cells by hydroxyurea, colchicine or heat-shock treatment. By crossing these results with cell-type-specific transcriptomics, we identified epithelial genes up-regulated upon loss of neurogenesis: transcription factors (Dlx, Dlx1, DMBX1/Manacle, Ets1, Gli3, KLF11, LMX1A, ZNF436, Shox1), epitheliopeptides (Arminins, PW peptide), neurosignalling components (CAMK1D, DDCl2, Inx1), ligand-ion channel receptors (CHRNA1, NaC7), G-Protein Coupled Receptors and FMRFRL. Hence epitheliomuscular cells seemingly enhance their sensing ability when neurogenesis is compromised. This unsuspected plasticity might reflect the extended multifunctionality of epithelial-like cells in early eumetazoan evolution.
authors.affiliation: Department of Genetics and Evolution, Institute of Genetics and Genomics in Geneva (IGe3), Faculty of Sciences, University of Geneva, 30 quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland.
authors.forename: Y
authors.identifier: http://orcid.org/0000-0002-6162-1527
authors.initials: Y
authors.lastname: Wenger
authors.affiliation: Department of Genetics and Evolution, Institute of Genetics and Genomics in Geneva (IGe3), Faculty of Sciences, University of Geneva, 30 quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland.
authors.forename: W
authors.identifier: http://orcid.org/0000-0002-8492-6470
authors.initials: W
authors.lastname: Buzgariu
authors.affiliation: Department of Genetics and Evolution, Institute of Genetics and Genomics in Geneva (IGe3), Faculty of Sciences, University of Geneva, 30 quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland brigitte.galliot@unige.ch.
authors.forename: B
authors.identifier: http://orcid.org/0000-0001-7596-8284
authors.initials: B
authors.lastname: Galliot
mesh_terms: D000818:Animals; D004847:Epithelial Cells / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology*; D006829:Hydra / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D055495:Neurogenesis / Q000235:genetics / Q000502:physiology*; D018377:Neurotransmitter Agents / Q000235:genetics / Q000378:metabolism; D012313:RNA / Q000235:genetics / Q000378:metabolism; D013234:Stem Cells / Q000502:physiology; D059467:Transcriptome
chemical_list: D018377:Neurotransmitter Agents; D012313:RNA
keywords: Hydra adult neurogenesis; RNA-seq transcriptomics; flow cytometry cell sorting; hydroxyurea; interstitial stem cells; plasticity of epithelial cells