Human Schwann‐like cells derived from adipose‐derived mesenchymal stem cells rapidly de‐differentiate in the absence of stimulating medium

Abstract

Finding a viable cell-based therapy to address peripheral nerve injury holds promise for enhancing the currently suboptimal microsurgical approaches to peripheral nerve repair. Autologous nerve grafting is the current gold standard for surgical repair of nerve gaps; however, this causes donor nerve morbidity in the patient, and the results remain unsatisfactory. Transplanting autologous Schwann cells (SCs) results in similar morbidity, as well as limited cell numbers and restricted potential for expansion in vitro. Adipose-derived stem cells (ASCs), 'differentiated' towards an SC-like phenotype in vitro (dASCs), have been presented as an alternative to SC therapies. The differentiation protocol stimulates ASCs to mimic the SC phenotype; however, the efficacy of dASCs in nerve repair is not yet convincing, and the practicality of the SC-like phenotype is unproven. Here, we examined the stability of dASCs by withdrawing differentiation medium for 72 h after the full 18-day differentiation protocol, and measuring changes in morphology, gene expression, and protein levels. Withdrawal of differentiation medium from dASCs resulted in a rapid reversion to stem cell-like characteristics. Quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay analyses demonstrated a significant reduction in gene and protein expression of growth factors that were expressed at high levels following 'differentiation'. Therefore, we question the relevance of differentiation to an SC-like phenotype, as withdrawal of differentiation medium, a model of transplantation into an injured nerve, results in rapid reversion of the dASC phenotype to stem cell-like characteristics. Further investigation into the differentiation process and the response of dASCs to an injured environment must be undertaken prior to the use of dASCs in peripheral nerve repair therapies.

Human bone marrow‐derived MSCs spontaneously express specific Schwann cell markers

“…This emphasises the heterogenous nature of MSC populations. Post‐transdifferentiation, we observed significant changes in the morphology of hBM‐MSCs from flattened fibroblast‐like cells into an SC‐like morphology, that is, more spindle‐shaped cells, and more bi‐ and tripolar cells with elongated processes, as reported elsewhere (Dezawa et al, ; Keilhoff et al, ; Shimizu et al, ; Ladak et al, ; Razavi et al, ; Hassan et al, ; Faroni et al, ; Cai et al, ). However, these significant changes in morphology were accompanied by inconsistent gene expression at the mRNA and protein levels.…”

“…Previous studies have concluded that it is insufficient to indicate the generation of Schwann cell‐like cells based on morphological changes in vitro as this was unlikely to be accompanied by a significant increase in the expression of neural markers (Krabbe et al, ) or to define the fate of SC (Keilhoff et al, ). Furthermore, the Schwann cell‐like cell morphology was shown to be transient and was reversed upon the removal of the induction media (Faroni et al, ). A similar conclusion was reached in our study.…”

Advances in Controlling Differentiation of Adult Stem Cells for Peripheral Nerve Regeneration

“…They further proved that the cells continued to maintain their status even without exogenous transdifferentiation-inducing factors or neurons. On the other hand, Faroni et al [129] observed that the withdrawal of transdifferentiation medium resulted in a rapid reversion from SCs back to stem cell-like characteristics for transdifferentiated adipose-derived stem cells. This was accompanied by significant reduction in gene and protein expression of growth factors for SC-like phenotypes.…”

Photoreceptor Therapy: Generation of Neurosphere-Like Cells from Human Mesenchymal Stem Cells Expressing Erythropoietin

“…Also, functional studies using animal models will be needed to shed light on the state of cell integration in neural circuits. Noteworthy of mentioning is these neurospheres can be used for directed differentiation into cholinergic- (Danielyan et al 2009) and dopaminergic- (Chun et al 2016;Hayashi et al 2013) neurons, Schwann cells (Faroni et al 2016) or neuro-glial cells (Miceli et al 2016;Radtke et al 2009) at larger quantities, to cure other neurodegenerative diseases too (Figure 4).…”