title: Non-nuclear Wld(S) determines its neuroprotective efficacy for axons and synapses in vivo.
abstract: Axon degeneration contributes widely to neurodegenerative disease but its regulation is poorly understood. The Wallerian degeneration slow (Wld(S)) protein protects axons dose-dependently in many circumstances but is paradoxically abundant in nuclei. To test the hypothesis that Wld(S) acts within nuclei in vivo, we redistributed it from nucleus to cytoplasm in transgenic mice. Surprisingly, instead of weakening the phenotype as expected, extranuclear Wld(S) significantly enhanced structural and functional preservation of transected distal axons and their synapses. In contrast to native Wld(S) mutants, distal axon stumps remained continuous and ultrastructurally intact up to 7 weeks after injury and motor nerve terminals were robustly preserved even in older mice, remaining functional for 6 d. Moreover, we detect extranuclear Wld(S) for the first time in vivo, and higher axoplasmic levels in transgenic mice with Wld(S) redistribution. Cytoplasmic Wld(S) fractionated predominantly with mitochondria and microsomes. We conclude that Wld(S) can act in one or more non-nuclear compartments to protect axons and synapses, and that molecular changes can enhance its therapeutic potential.
authors.affiliation: Laboratory of Molecular Signalling, The Babraham Institute, Cambridge, UK.
authors.forename: Bogdan
authors.initials: B
authors.lastname: Beirowski
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Babetto
authors.forename: Jon
authors.initials: J
authors.lastname: Gilley
authors.forename: Francesca
authors.initials: F
authors.lastname: Mazzola
authors.forename: Laura
authors.initials: L
authors.lastname: Conforti
authors.forename: Lucie
authors.initials: L
authors.lastname: Janeckova
authors.forename: Giulio
authors.initials: G
authors.lastname: Magni
authors.forename: Richard R
authors.initials: RR
authors.lastname: Ribchester
authors.forename: Michael P
authors.initials: MP
authors.lastname: Coleman
mesh_terms: D000367:Age Factors; D000409:Alanine / Q000235:genetics; D016564:Amyloid beta-Protein Precursor / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D001120:Arginine / Q000235:genetics; D001369:Axons / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D002461:Cell Line, Transformed; D003714:Denervation / Q000379:methods; D004195:Disease Models, Animal; D004576:Electromyography; D006801:Humans; D008164:Luminescent Proteins / Q000235:genetics; D051379:Mice; D008822:Mice, Transgenic; D046529:Microscopy, Electron, Transmission; D008861:Microsomes / Q000378:metabolism / Q000473:pathology; D008928:Mitochondria / Q000378:metabolism / Q000473:pathology; D024101:Mitochondrial Proteins / Q000378:metabolism; D018482:Muscle, Skeletal / Q000503:physiopathology; D016297:Mutagenesis, Site-Directed / Q000379:methods; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism*; D009469:Neuromuscular Junction / Q000473:pathology / Q000503:physiopathology* / Q000648:ultrastructure; D009924:Organ Culture Techniques; D010525:Peripheral Nerves / Q000503:physiopathology; D021381:Protein Transport / Q000235:genetics; D051381:Rats; D013347:Subcellular Fractions / Q000378:metabolism; D014162:Transfection / Q000379:methods; D014404:Tubulin / Q000378:metabolism; D014855:Wallerian Degeneration / Q000235:genetics / Q000473:pathology* / Q000517:prevention & control*
chemical_list: D016564:Amyloid beta-Protein Precursor; D008164:Luminescent Proteins; D024101:Mitochondrial Proteins; D009419:Nerve Tissue Proteins; C488416:Tubb3 protein, rat; D014404:Tubulin; C442580:Wld protein, mouse; D001120:Arginine; D000409:Alanine