Non-Myelinating Schwann Cells in Health and Disease

Abstract

Non-myelinating Schwann cells (NMSCs) are one of the two major phenotypes of Schwann cells. NMSCs are of different types and have various locations. In the peripheral nervous system, NMSC, named Remak Schwann cells (RSC), accommodate multiple small-caliber axons, forming Remak bundles. NMSC, named perisynaptic/terminal Schwann cells, are found at the distal end of motor nerve terminals at the neuromuscular junction (NMJ). Thus, NMSCs proved to serve different functions according to their distribution such as maintenance of the axon and NMJ, peripheral nerve regeneration, or remodeling of the NMJ. Schwann cells (SCs) retain their proliferation capacity in the case of nerve injury or demyelination and provide support for the neuronal cells through paracrine signaling. Here we present an overview of their phenotypes and tissue distribution focusing on their emerging involvement in various peripheral nerve diseases.

PCSK9 deficiency promotes the development of peripheral neuropathy

“…Similar morphological differences between these mice were also observed in their sural nerve that mostly contain non-myelinated axons (data not shown). Remak bundles normally consist in a single non-myelinating SC that ensheaths several small C-type axon fibers separately (24). In PCSK9 knockouts, most axons within Remak bundles appeared to fasciculate together (Figure 3E), with an abnormal presence of vacuoles within these bundles (Supplementary figure 3D).…”

Effects of PACAP on Schwann Cells: Focus on Nerve Injury

“…Moreover, these cells modulate pain sensitivity in peripheral sensory neuropathies. In accord, it has been demonstrated that even in absence of injury, alterations between axon-Remak cells interactions are followed by neuropathic pain [2,8]. Meanwhile, Schwann cells wrap larger axons of sensory and motor neurons [2,9].…”

The role of exercise on peripheral nerve regeneration: from animal model to clinical application

“…in diameter shows conducting action potential less than 1 m/s, whereas large-diameter heavily myelinated axons conduct at a rate of approximately 100 m/s [12].…”

“…Within a peripheral nerve, there are both myelinated and nonmyelinated nerve fibers. Both types of fibers are supported by Schwann cells, representing the most abundant glial cells of the PNS [12]. Schwann cells exist in two different cell types: Remak cells, or non-myelin Schwann cells, and myelin Schwann cells.…”