Two factor-based reprogramming of rodent and human fibroblasts into Schwann cells

Pietro Giuseppe Mazzara,Alessandro Sessa,Vania Broccoli,Angelo Quattrini,Giulia Ronchi,Alessandra Ricca,Stefano Geuna,Angelo Iannielli,Marta Pellegatta,Serena Gea Giannelli,Luca Massimino,Ubaldo Del Carro,Carla Taveggia,Marco Cursi,Cinzia Cancellieri,Angela Gritti

doi:10.1038/ncomms14088

Abstract

Schwann cells (SCs) generate the myelin wrapping of peripheral nerve axons and are promising candidates for cell therapy. However, to date a renewable source of SCs is lacking. In this study, we show the conversion of skin fibroblasts into induced Schwann cells (iSCs) by driving the expression of two transcription factors, Sox10 and Egr2. iSCs resembled primary SCs in global gene expression profiling and PNS identity. In vitro, iSCs wrapped axons generating compact myelin sheaths with regular nodal structures. Conversely, iSCs from Twitcher mice showed a severe loss in their myelinogenic potential, demonstrating that iSCs can be an attractive system for in vitro modelling of PNS diseases. The same two factors were sufficient to convert human fibroblasts into iSCs as defined by distinctive molecular and functional traits. Generating iSCs through direct conversion of somatic cells offers opportunities for in vitro disease modelling and regenerative therapies.

Highlights

Schwann cells (SCs) generate the myelin wrapping of peripheral nerve axons and are promising candidates for cell therapy
The factors were individually cloned in doxycycline-inducible lentiviral vectors and E15.5 mouse embryonic fibroblasts were infected with one or more lentiviruses and cultured in a SC culture medium supplemented with Neuregulin-1 (NRG1) and forskolin (Fsk) (Fig. 1a)[20]
We realized that primary cultures of embryonic and adult skin fibroblasts often contain a fraction of CD271 þ cells with neural crest stem cell features and can give rise to SC precursors (Supplementary Fig. 1a,b)[21]

Summary

Introduction

Schwann cells (SCs) generate the myelin wrapping of peripheral nerve axons and are promising candidates for cell therapy. A valuable therapeutic option for the treatment of peripheral nerve insults is represented by the transplantation of SCs, alone or in combination with the nerve guide[4,5] This therapeutic approach is strongly limited by the current lack of a renewable source of SCs in humans. These approaches are limited by the need of isolating rare progenitor cells in tissues Most of these methods are laborious and generate SCs with low myelination efficiency that strongly limits the development of cell-based therapies and in vitro disease-modelling studies. To overcome these limitations, we speculated that a direct cell conversion approach to convert skin fibroblasts into SCs would offer a more straightforward and convenient procedure. The same factor combination could be used to promote conversion of human post-natal fibroblasts into SCs with comparable properties and functions

Methods

Results

Conclusion