Schwann Cell Responses and Plasticity in Different Dental Pulp Scenarios

Abstract

Mammalian teeth have evolved as dentin units that enclose a complex system of sensory innervation to protect and preserve their structure and function. In human dental pulp (DP), mechanosensory and nociceptive fibers form a dense meshwork of nerve endings at the coronal dentin-pulp interface, which arise from myelinated and non-myelinated axons of the Raschkow plexus (RP). Schwann cells (SCs) play a crucial role in the support, maintenance and regeneration after injury of these fibers. We have recently characterized two SC phenotypes hierarchically organized within the coronal and radicular DP in human teeth. Myelinating and non-myelinating SCs (nmSCs) display a high degree of plasticity associated with nociceptive C-fiber sprouting and axonal degeneration in response to DP injuries from dentin caries or physiological root resorption (PRR). By comparative immunolabeling, confocal and electron microscopy, we have characterized short-term adaptive responses of SC phenotypes to nerve injuries, and long-term changes related to aging. An increase of SCs characterizes the early responses to caries progression in association with axonal sprouting in affected DP domains. Moreover, during PRR, the formation of bands of Büngner is observed as part of SC repair tracks functions. On the other hand, myelinated axon density is significantly reduced with tooth age, as part of a gradual decrease in DP defense and repair capacities. The remarkable plasticity and capacity of SCs to preserve DP innervation in different dental scenarios constitutes a fundamental aspect to improve clinical treatments. This review article discusses the central role of myelinating and non-mSCs in long-term tooth preservation and homeostasis.

Establishment of inclusive single-cell transcriptome atlases from mouse and human tooth as powerful resource for dental research

“…Since Schwann cells have been described to play crucial roles during tooth development (i.e., by giving rise to dental MSC and OB) and regeneration (i.e., by co-orchestrating the pulpal inflammatory response and peripheral nerve repair) ( Kaukua et al, 2014 ; Couve and Schmachtenberg, 2018 ), we focused on potential ligand-receptor interactions originating from the Schwann cell cluster towards the various DE and DM cell subsets. Interestingly, both in mouse and human, Fgf1 - Fgfr1 interactions between Schwann cells and the majority of annotated cell types were projected, as well as Fgf1 - Fgfr2 and Fgf1 - Fgfr3 interactions although with more distinct clusters, all with Fgf1 originating from the Schwann cells ( Figure 5A ).…”

Secreted Frizzled-Related Protein 1 Promotes Odontoblastic Differentiation and Reparative Dentin Formation in Dental Pulp Cells

“…Various signals, such as growth factors, chemokines, and extracellular matrices, are involved in the regeneration and homeostasis of the dentin-pulp complex [ 25 , 26 , 27 , 28 , 29 , 30 ]. Additionally, the mesenchymal stem/progenitor cell population in pulp is considered to differentiate into odontoblast-like cells, which generate reparative dentin in response to injury [ 10 , 31 ].…”

Schwann Cells in Digestive System Disorders

“…Additionally, tooth SCs have a special status in dental pulp where they perform stem cell [ 22 ] functions, and modulate immune response [ 57 ] and nociception [ 92 ]. For a broader discussion of this topic, we refer the reader to a recent review [ 93 ].…”