Identity, developmental restriction and reactivity of extralaminar cells capping mammalian neuromuscular junctions

F. A. Court, T. H. Gillingwater, S. Melrose, D. L. Sherman, K. N. Greenshields, A. J. Morton, J. B. Harris, H. J. Willison, R. R. Ribchester

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

Neuromuscular junctions (NMJs) are normally thought to comprise three major cell types: skeletal muscle fibres, motor neuron terminals and perisynaptic terminal Schwann cells. Here we studied a fourth population of junctional cells in mice and rats, revealed using a novel cytoskeletal antibody (2166). These cells lie outside the synaptic basal lamina but form caps over NMJs during postnatal development. NMJ-capping cells also bound rPH, HM-24, CD34 antibodies and cholera toxin B subunit. Bromodeoxyuridine incorporation indicated activation, proliferation and spread of NMJ-capping cells following denervation in adults, in advance of terminal Schwann cell sprouting. The NMJ-capping cell reaction coincided with expression of tenascin-C but was independent of this molecule because capping cells also dispersed after denervation in tenascin-C-null mutant mice. NMJ-capping cells also dispersed after local paralysis with botulinum toxin and in atrophic muscles of transgenic R6/2 mice. We conclude that NMJ-capping cells (proposed name 'kranocytes') represent a neglected, canonical cellular constituent of neuromuscular junctions where they could play a permissive role in synaptic regeneration.
Original languageEnglish
Pages (from-to)3901-3911
Number of pages11
JournalJournal of Cell Science
Issue number23
Publication statusPublished - Dec 2008

Keywords / Materials (for Non-textual outputs)

  • Neuromuscular junction
  • Motor endplate
  • Motor nerve terminal
  • Schwann cell
  • Kranocyte
  • CD34
  • Neuregulin
  • Tenascin


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