title: Level and localization of polysialic acid is critical for early peripheral nerve regeneration.
abstract: PolySia, the most striking post-translational modification of the neural cell adhesion molecule, is down-regulated during postnatal development. After peripheral nerve lesion, polySia is located on neuronal and glial cells normally not synthesizing polySia. However, structural consequences of reduced polySia content for peripheral nerve regeneration have not yet been clear. Furthermore, the contribution of sialyltransferases ST8SiaII and ST8SiaIV for the up-regulation of polySia has not been studied so far. In order to investigate the impact of polySia on regeneration processes of myelinated axons, we examined mouse mutants retaining only one functional sialyltransferase allele. In the absence of ST8SiaII, quantification of myelinated axons revealed a significant decrease in number and size of regenerated fibers without impairment of remyelination. In contrast, St8SiaIV deficiency resulted in increased fiber outgrowth and axonal maturation. Western blot analysis demonstrated that both ST8SiaII and St8SiaIV direct up-regulation of polySia. Cell-specific induction of polySia in myelinating Schwann cells and on regenerated axons in the presence of ST8SiaIV, but not ST8SiaII, indicates that not only the amount of polySia but also its cellular localization has a high impact on the regeneration progress of peripheral nerves.
authors.affiliation: Hannover Medical School, Institute of Neuroanatomy, Germany. jungnickel.julia@mh-hannover.de
authors.forename: Julia
authors.initials: J
authors.lastname: Jungnickel
authors.forename: Christian
authors.initials: C
authors.lastname: Brämer
authors.forename: Paul
authors.initials: P
authors.lastname: Bronzlik
authors.forename: Esther
authors.initials: E
authors.lastname: Lipokatic-Takacs
authors.forename: Birgit
authors.initials: B
authors.lastname: Weinhold
authors.forename: Rita
authors.initials: R
authors.lastname: Gerardy-Schahn
authors.forename: Claudia
authors.initials: C
authors.lastname: Grothe
mesh_terms: D000818:Animals; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009186:Myelin Sheath / Q000378:metabolism; D009416:Nerve Regeneration / Q000502:physiology*; D019006:Neural Cell Adhesion Molecules / Q000378:metabolism; D010525:Peripheral Nerves / Q000166:cytology / Q000473:pathology / Q000502:physiology*; D011499:Protein Processing, Post-Translational; D012794:Sialic Acids / Q000378:metabolism*; D012799:Sialyltransferases / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D019006:Neural Cell Adhesion Molecules; D012794:Sialic Acids; C021319:polysialic acid; D012799:Sialyltransferases