title: Environmental enrichment rescues memory in mice deficient for the polysialytransferase ST8SiaIV.
abstract: The neural cell adhesion molecule NCAM and its association with the polysialic acid (PSA) are believed to contribute to brain structural plasticity that underlies memory formation. Indeed, the attachment of long chains of PSA to the glycoprotein NCAM down-regulates its adhesive properties by altering cell-cell interactions. In the brain, the biosynthesis of PSA is catalyzed by two polysialyltransferases, which are differentially regulated during lifespan. One of them, ST8SiaIV (PST), is predominantly expressed during adulthood whereas the other one, ST8SiaII (STX), dominates during embryonic and post-natal development. To understand the role played by ST8SiaIV during learning and memory and its underlying hippocampal plasticity, we used knockout mice deleted for the enzyme ST8SiaIV (PST-ko mice). At adult age, PST-ko mice show a drastic reduction of PSA-NCAM expression in the hippocampus and intact hippocampal adult neurogenesis. We found that these mice display impaired long-term but not short-term memory in both, spatial and non-spatial behavioral tasks. Remarkably, memory deficits of PST-ko mice were abolished by exposure to environmental enrichment that was also associated with an increased number of PSA-NCAM expressing new neurons in the dentate gyrus of these mice. Whether the presence of a larger pool of immature, likely plastic, new neurons favored the rescue of long-term memory in PST-ko mice remains to be determined. Our findings add new evidence to the role played by PSA in memory consolidation. They also suggest that PSA synthesized by PST critically controls the tempo of new neurons maturation in the adult hippocampus.
authors.affiliation: Université de Toulouse, UPS, Centre de Recherches sur la Cognition Animale, 118 route de Narbonne, 31062, Toulouse Cedex 9, France.|Centre de Recherches sur la Cognition Animale (CNRS UMR 5169) Université Paul Sabatier, 118 Route de Narbonne, 31062, Toulouse Cedex 4, France.
authors.forename: Meike
authors.initials: M
authors.lastname: Zerwas
authors.affiliation: Université de Toulouse, UPS, Centre de Recherches sur la Cognition Animale, 118 route de Narbonne, 31062, Toulouse Cedex 9, France.|Centre de Recherches sur la Cognition Animale (CNRS UMR 5169) Université Paul Sabatier, 118 Route de Narbonne, 31062, Toulouse Cedex 4, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Trouche
authors.affiliation: Université de Toulouse, UPS, Centre de Recherches sur la Cognition Animale, 118 route de Narbonne, 31062, Toulouse Cedex 9, France.|Centre de Recherches sur la Cognition Animale (CNRS UMR 5169) Université Paul Sabatier, 118 Route de Narbonne, 31062, Toulouse Cedex 4, France.
authors.forename: Kevin
authors.initials: K
authors.lastname: Richetin
authors.affiliation: Université de Toulouse, UPS, Centre de Recherches sur la Cognition Animale, 118 route de Narbonne, 31062, Toulouse Cedex 9, France.|Centre de Recherches sur la Cognition Animale (CNRS UMR 5169) Université Paul Sabatier, 118 Route de Narbonne, 31062, Toulouse Cedex 4, France.
authors.forename: Timothé
authors.initials: T
authors.lastname: Escudé
authors.affiliation: Université de Toulouse, UPS, Centre de Recherches sur la Cognition Animale, 118 route de Narbonne, 31062, Toulouse Cedex 9, France.|Centre de Recherches sur la Cognition Animale (CNRS UMR 5169) Université Paul Sabatier, 118 Route de Narbonne, 31062, Toulouse Cedex 4, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Halley
authors.affiliation: Institute for Cellular Chemistry, Hannover Medical School, 30626, Hannover, Germany.
authors.forename: Rita
authors.initials: R
authors.lastname: Gerardy-Schahn
authors.affiliation: Université de Toulouse, UPS, Centre de Recherches sur la Cognition Animale, 118 route de Narbonne, 31062, Toulouse Cedex 9, France.|Centre de Recherches sur la Cognition Animale (CNRS UMR 5169) Université Paul Sabatier, 118 Route de Narbonne, 31062, Toulouse Cedex 4, France.
authors.forename: Laure
authors.initials: L
authors.lastname: Verret
authors.affiliation: Université de Toulouse, UPS, Centre de Recherches sur la Cognition Animale, 118 route de Narbonne, 31062, Toulouse Cedex 9, France. claire.rampon@univ-tlse3.fr.|Centre de Recherches sur la Cognition Animale (CNRS UMR 5169) Université Paul Sabatier, 118 Route de Narbonne, 31062, Toulouse Cedex 4, France. claire.rampon@univ-tlse3.fr.
authors.forename: Claire
authors.initials: C
authors.lastname: Rampon
mesh_terms: D000818:Animals; D004780:Environment, Controlled; D005260:Female; D006624:Hippocampus / Q000201:enzymology*; D008297:Male; D008568:Memory / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D019006:Neural Cell Adhesion Molecules / Q000378:metabolism / Q000502:physiology*; D055495:Neurogenesis; D009473:Neuronal Plasticity; D012799:Sialyltransferases / Q000235:genetics / Q000502:physiology*; D065852:Spatial Memory / Q000502:physiology
chemical_list: D019006:Neural Cell Adhesion Molecules; D012799:Sialyltransferases; C525848:ST8SiaIV protein, mouse
keywords: Hippocampus; Memory; Neurogenesis; PSA-NCAM; Polysialylation; Polysialyltransferase ST8iaIV/PST