Neuron–glia interactions: the roles of Schwann cells in neuromuscular synapse formation and function

Abstract

Synopsis The NMJ (neuromuscular junction) serves as the ultimate output of the motor neurons. The NMJ is composed of a presynaptic nerve terminal, a postsynaptic muscle and perisynaptic glial cells. Emerging evidence has also demonstrated an existence of perisynaptic fibroblast-like cells at the NMJ. In this review, we discuss the importance of Schwann cells, the glial component of the NMJ, in the formation and function of the NMJ. During development, Schwann cells are closely associated with presynaptic nerve terminals and are required for the maintenance of the developing NMJ. After the establishment of the NMJ, Schwann cells actively modulate synaptic activity. Schwann cells also play critical roles in regeneration of the NMJ after nerve injury. Thus, Schwann cells are indispensable for formation and function of the NMJ. Further examination of the interplay among Schwann cells, the nerve and the muscle will provide insights into a better understanding of mechanisms underlying neuromuscular synapse formation and function.

Evidence for mast cells contributing to neuromuscular pathology in an inherited model of ALS

“…Perisynaptic Schwann cells are glial cells at the NMJs that ensure the synapse stability, maintenance, and repair during damage or denervation (41). Perisynaptic Schwann cells respond to ALS-induced denervation with profound morphological and phenotypic changes (17), retracting processes from the NMJs while extending processes to other endplate areas (42).…”

Mechanisms Regulating Neuromuscular Junction Development and Function and Causes of Muscle Wasting

“…By extending processes from denervated synapses they guide regenerating motor axons to vacant synaptic sites; in partially denervated muscle, Schwann cell processes extend from denervated to nearby intact synapses where they induce the surviving nerve terminals to sprout and grow back to denervated synaptic sites (404,405). For more detailed accounts on the role of Schwann cells in NMJ development and function, the reader is referred to detailed reviews by others (110,137,413).…”

Wnt Signaling in Neuromuscular Junction Development

“…Likewise, because many aspects of Wnt signaling are conserved across species, it will be exciting to test whether the continuous, ongoing requirement for C. elegans Wnt, CWN-2, in synaptic plasticity (Jensen et al 2012) is also at play in other model organisms, such as the fly, zebrafish, or other vertebrates. Furthermore, the contribution to NMJ development and function of terminal Schwann cells in vertebrates (Feng and Ko 2008;Sugiura and Lin 2011) is poised to lead to novel insights.…”