Transfer of Vesicles From Schwann Cells to Axons: a Novel Mechanism of Communication in the Peripheral Nervous System

Abstract

Schwann cells (SCs) are the glial component of the peripheral nervous system, with essential roles during development and maintenance of axons, as well as during regenerative processes after nerve injury. SCs increase conduction velocities by myelinating axons, regulate synaptic activity at presynaptic nerve terminals and are a source of trophic factors to neurons. Thus, development and maintenance of peripheral nerves are crucially dependent on local signaling between SCs and axons. In addition to the classic mechanisms of intercellular signaling, the possibility of communication through secreted vesicles has been poorly explored to date. Interesting recent findings suggest the occurrence of lateral transfer mediated by vesicles from glial cells to axons that could have important roles in axonal growth and axonal regeneration. Here, we review the role of vesicular transfer from SCs to axons and propose the advantages of this means in supporting neuronal and axonal maintenance and regeneration after nerve damage.

Extracellular vesicles as mediators of neuron-glia communication

“…Oligodendrocytes can then utilize these vesicles to locally transfer metabolites, protective proteins, glycolytic enzymes, mRNA, and miRNA to axons, which may maintain axonal integrity (Frühbeis et al, 2013). In the peripheral nervous system, evidence suggests that myelinating Schwann cells shuttle supportive cargo to axons by vesicular means facilitating regeneration of axons after injury (Lopez-Verrilli and Court, 2012). …”

Extracellular vesicles and intercellular communication within the nervous system

“…EVs are released from virtually all cell types in the brain, including neural stem/progenitor cells (5,6), neurons (7)(8)(9), astrocytes (9-13), oligodendrocytes (13)(14)(15), and microglia (16,17) as well as Schwann cells and neurons in the peripheral nervous system (18)(19)(20). A schematic overview of potential EV-mediated interactions in the nervous system is provided in Figure 1.…”

Exosomes function in cell–cell communication during brain circuit development

“…Within the nervous system, as in cancer, exosomes play both beneficial and pathological roles [2,14]. Neurons and glia release exosomes in vitro and in vivo [2,14,33–35]. Trophic support from oligodendrocytes and astrocytes to neurons is thought to be conveyed by exosomes[34].…”