Comparison of human skin‐ and nerve‐derived Schwann cells reveals many similarities and subtle genomic and functional differences

Abstract

Skin is an easily accessible tissue and a rich source of Schwann cells (SCs). Toward potential clinical application of autologous SC therapies, we aim to improve the reliability and specificity of our protocol to obtain SCs from small skin samples. As well, to explore potential functional distinctions between skin-derived SCs (Sk-SCs) and nerve-derived SCs (N-SCs), we used single-cell RNA-sequencing and a series of in vitro and in vivo assays. Our results showed that Sk-SCs expressed typical SC markers. Single-cell sequencing of Sk-and N-SCs revealed an overwhelming overlap in gene expression with the exception of HLA genes which were preferentially upregulated in Sk-SCs. In vitro, both cell types exhibited similar levels of proliferation, migration, uptake of myelin debris and readily associated with neurites when cocultured with human iPSC-induced motor neurons. Both exhibited ensheathment of multiple neurites and early phase of myelination, especially in N-SCs. Interestingly, dorsal root ganglion (DRG) neurite outgrowth assay showed substantially more complexed neurite outgrowth in DRGs exposed to Sk-SC conditioned media compared to those from N-SCs. Multiplex ELISA array revealed shared growth factor profiles, but Sk-SCs expressed a higher level of VEGF. Transplantation of Sk-and N-SCs into injured peripheral nerve in nude rats and NOD-SCID mice showed close association of both SCs to regenerating axons. Myelination of rodent axons was observed infrequently by N-SCs, but absent in Sk-SC xenografts. Overall, our results showed that Sk-SCs share near-identical properties to N-SCs but with subtle differences that could potentially enhance their therapeutic utility.

Behavioral and axon histomorphometric analyses after intraneural transplantation of human skin‐ and nerve‐derived Schwann cells in nude rats

“…The subtle differences may reflect the unique properties of Sk-SCs, such as higher VEGF release, which may influence axonal growth and SC migration. 5,11,12 Future studies may consider injuring the sciatic nerve proper to elicit a more severe injury to discern differences.…”

“…The entire segment of nerve 1 cm distal to the crush site was collected for the examination of interaction between human cells and host axons, as reported previously. 5 A 2-to 3-mm nerve segment immediately distal to that portion was harvested and processed for transmission electron microscopy. Axon histomorphometry was analyzed using the SEM prediction model in AxonDeepSeg.…”

“…Our previous comparative study between human skin-derived SCs (Sk-SCs) and nerve-derived SCs (N-SCs) showed largely overlapping transcriptomic profiles and phenotypic characteristics. 5 However, each subtype maintained its individual differences, including higher vascular endothelial growth factor (VEGF) and collagen release in Sk-SCs and increased propensity to form myelin in N-SCs when cocultured with human induced pluripotent stem cell (iPSC)-induced motor neurons in a three-dimensional culture model. 5 To explore functional differences between Sk-SCs and N-SCs, we injected these SCs, together with dermal fibroblasts from the same donor, into the injured tibial nerve of nude rats.…”

“…5 However, each subtype maintained its individual differences, including higher vascular endothelial growth factor (VEGF) and collagen release in Sk-SCs and increased propensity to form myelin in N-SCs when cocultured with human induced pluripotent stem cell (iPSC)-induced motor neurons in a three-dimensional culture model. 5 To explore functional differences between Sk-SCs and N-SCs, we injected these SCs, together with dermal fibroblasts from the same donor, into the injured tibial nerve of nude rats. Morphologically, we showed that both subtypes were able to align and possibly ensheath rodent axons after transplantation, but no myelination was observed in this rat model.…”

“…Morphologically, we showed that both subtypes were able to align and possibly ensheath rodent axons after transplantation, but no myelination was observed in this rat model. 5 In this study we report on longitudinal assessments of functional recovery using gait and sensory testing assays, complemented with axon histomorphometry profiles of the injured nerves.…”