BoNT/Action beyond neurons

Abstract

Botulinum neurotoxin type A (BoNT/A) has expanded its therapeutic uses beyond neuromuscular disorders to include treatments for various pain syndromes and neurological conditions. Originally recognized for blocking acetylcholine release at neuromuscular junctions, BoNT/A's effects extend to both peripheral and central nervous systems. Its ability to undergo retrograde transport allows BoNT/A to modulate synaptic transmission and reduce pain centrally, influencing neurotransmitter systems beyond muscle control. BoNT/A also interacts with glial cells, such as Schwann cells, satellite glial cells, astrocytes, microglia, and oligodendrocytes. Schwann cells, key to peripheral nerve regeneration, are directly influenced by BoNT/A, which promotes their proliferation and enhances remyelination. Satellite glial cells, involved in sensory neuron regulation, show reduced glutamate release in response to BoNT/A, aiding in pain relief. In the CNS, BoNT/A modulates astrocyte activity, reducing excitotoxicity and inflammation, which is relevant in conditions like epilepsy. Microglia, the CNS's immune cells, shift from a pro-inflammatory to a neuroprotective state when treated with BoNT/A, enhancing tissue repair. Additionally, BoNT/A promotes oligodendrocyte survival and remyelination, especially after spinal cord injury. Overall, BoNT/A's ability to target both neurons and glial cells presents a multifaceted therapeutic strategy for neurological disorders, pain management, and CNS repair. Further research is necessary to fully elucidate its mechanisms and optimize its clinical application.

Keywords: Botulinum neurotoxins; Glia; Neurological disorders; Pain; Spinal cord injury.