The neuromuscular junction is exposed to different types of insults including mechanical traumas, toxins or autoimmune antibodies and, accordingly, has retained through evolution a remarkable ability to regenerate. Regeneration is driven by multiple signals that are exchanged among the cellular components of the junction. These signals are largely unknown.
Miller Fisher syndrome is a variant of Guillain-Barré syndrome caused by autoimmune antibodies specific for epitopes of peripheral axon terminals. Using an animal model of Miller Fisher syndrome, we recently reported that a monoclonal anti-polysialoganglioside GQ1b antibody plus complement damages nerve terminals with production of mitochondrial hydrogen peroxide, that activates Schwann cells. Several additional signaling molecules are likely to be involved in the activation of the regenerative program in these cells.
Using an in vitro cellular model consisting of co-cultured primary neurons and Schwann cells, we found that ATP is released by neurons injured by the anti-GQ1b antibody plus complement. Neuron derived ATP acts as alarm messenger for Schwann cells, where it induces the activation of intracellular pathways including calcium signaling, cyclic AMP and CREB, which in turn produce signals that promote nerve regeneration.
These results contribute to define the cross-talk taking place at the neuromuscular junction attacked by anti-gangliosides autoantibodies plus complement, functional to nerve regeneration, that are likely to be valid also for other peripheral neuropathies.
- Received September 22, 2016.
- Accepted December 14, 2016.
- © 2017. Published by The Company of Biologists Ltd
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