Chemical Conversion of Human Fibroblasts into Functional Schwann Cells

Abstract

SUMMARYDirect transdifferentiation of somatic cells is a promising approach to obtain patient-specific cells for numerous applications. However, conversion across germ-layer borders often requires ectopic gene expression with unpredictable side effects. Here, we present a gene-free approach that allows efficient conversion of human fibroblasts via a transient progenitor stage into Schwann cells, the major glial cell type of peripheral nerves. Using a multikinase inhibitor, we transdifferentiated fibroblasts into transient neural precursors that were subsequently further differentiated into Schwann cells. The resulting induced Schwann cells (iSCs) expressed numerous Schwann cell-specific proteins and displayed neurosupportive and myelination capacity in vitro. Thus, we established a strategy to obtain mature Schwann cells from human postnatal fibroblasts under chemically defined conditions without the introduction of ectopic genes.

Brief exposure to small molecules allows induction of mouse embryonic fibroblasts into neural crest‐like precursors

“…Here, we proposed a method for treatment of cells with small-molecule cocktails and confirmed the generation of peripheral neuronal cells from somatic cells. Although small molecule-based induction of specific cell types has been recently reported for neurons [37][38][39], pancreatic cells [40], and Schwann cells [41], induction of neural crest-like precursors and its derivatives have only been reported using a Sox10 gene-transfer method [42]. One of the most important features of step-by-step chemical treatment is the rapid treatment protocol.…”

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

“…and Krox20 • Culture in SC medium (PDGF-AA, bFGF, Heregulin, Forskolin) Thoma et al (2014) Sowa et al (2017) Incubation in sciatic nerve leachate or nerve conditioned medium.…”

“…Several attempts to generate SC from stem cells have been reported using adult stem cells (Shimizu et al, ; Shea et al, ; Razavi et al, ); embryonic stem cells (Roth et al, ; Ziegler et al, ); or induced pluripotent stem cells (Uemura et al, ). On the other hand, direct reprogramming of adult cells via either transgene or gene‐free approach (Thoma et al, ; Sowa et al, ) has obviated the challenges of cell sourcing. Since the first report in 1999 demonstrating the multipotency of MSCs from the bone marrow, MSCs remain popular among researchers and have emerged as strong candidates for cellular therapies for several reasons: i) the availability of autologous sources, for instance bone marrow and adipose tissues, and easily obtainable allogenic sources such as umbilical cord blood; ii) their strong capacity for in vitro proliferation; iii) reduced risks and ethical concerns; and iv) their immunomodulatory, migratory, and homing capabilities (Pittenger et al, ; Maltman et al, ; Wakao et al, ; Petrova, ).…”

Direct Conversion of Human Fibroblasts into Schwann Cells that Facilitate Regeneration of Injured Peripheral Nerve In Vivo

“…Retroviral vectors encoding these factors were infected into human fibroblasts either individually or in various combinations. The SC-like phenotype was assessed by expression of the s100b protein that is broadly expressed in almost all of the differentiation stages of SCs [36][37][38][39][40]. As shown in Supporting Information Figure S5, the s100b-positive cells were strongly induced after cotransduction of the two genes, SOX10 plus Krox20 (No.…”