Directly induced human Schwann cell precursors as a valuable source of Schwann cells

Han-Seop Kim,Cho Lok Song,Jae Yun Kim,Ji Eun Jeong,Yee Sook Cho

doi:10.1186/s13287-020-01772-x

Abstract

BackgroundSchwann cells (SCs) are primarily responsible for regeneration and repair of the peripheral nervous system (PNS). Renewable and lineage-restricted SC precursors (SCPs) are considered highly desirable and promising cell sources for the production of SCs and for studies of SC lineage development, but SCPs are extremely limited. Here, we present a novel direct conversion strategy for the generation of human SCPs, capable of differentiating into functional SCs.MethodsEasily accessible human skin fibroblast cells were directly induced into integration-free SCPs using episomal vectors (Oct3/4, Klf4, Sox2, L-Myc, Lin28 and p53 shRNA) under SCP lineage-specific chemically defined medium conditions. Induced SCPs (iSCPs) were further examined for their ability to differentiate into SCs. The identification and functionality of iSCPs and iSCP-differentiated SCs (iSCs) were confirmed according to morphology, lineage-specific markers, neurotropic factor secretion, and/or standard functional assays.ResultsHighly pure, Sox 10-positive of iSCPs (more than 95% purity) were generated from human skin fibroblasts within 3 weeks. Established iSCPs could be propagated in vitro while maintaining their SCP identity. Within 1 week, iSCPs could efficiently differentiate into SCs (more than 95% purity). The iSCs were capable of secreting various neurotrophic factors such as GDNF, NGF, BDNF, and NT-3. The in vitro myelinogenic potential of iSCs was assessed by myelinating cocultures using mouse dorsal root ganglion (DRG) neurons or human induced pluripotent stem cell (iPSC)-derived sensory neurons (HSNs). Furthermore, iSC transplantation promoted sciatic nerve repair and improved behavioral recovery in a mouse model of sciatic nerve crush injury in vivo.ConclusionsWe report a robust method for the generation of human iSCPs/iSCs that might serve as a promising cellular source for various regenerative biomedical research and applications, such as cell therapy and drug discovery, especially for the treatment of PNS injury and disorders.

Highlights

Schwann cells (SCs) are primarily responsible for regeneration and repair of the peripheral nervous system (PNS)
ISCPs are capable of differentiating into SCs We further investigated whether Induced Schwann cell precursors (SCPs) (iSCPs) can be induced to differentiate into SCs
Our results show that iSCPs are a useful source for SC production

Summary

Introduction

Schwann cells (SCs) are primarily responsible for regeneration and repair of the peripheral nervous system (PNS). Renewable and lineage-restricted SC precursors (SCPs) are considered highly desirable and promising cell sources for the production of SCs and for studies of SC lineage development, but SCPs are extremely limited. We present a novel direct conversion strategy for the generation of human SCPs, capable of differentiating into functional SCs. Schwann cells (SCs), the main glial cells of the peripheral nervous system (PNS), are developmentally derived from neural crest cells (NCCs) via intermediate Schwann cell precursors (SCPs) [1]. Great progress has been made in nerve tissue engineering and biomaterials to aid the process of nerve regeneration, the use of differentiated SCs to support neurons and form myelin sheaths in vitro and in vivo is still unsatisfactory, especially for long-gap nerve injury [13, 17,18,19]

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