Direct Reprogramming of Human Fibroblasts into Schwann Cells That Facilitate Regeneration of Injured Peripheral Nerve

Sowa Y, KishidaT, Morita D, Kodama T, Numajiri T, Mazda O

Author information:

Department of Plastic and Reconstructive Surgery , Kyoto Prefectural

University of Medicine, Graduate School of Medical Sciences , Kyoto , Japan.

Title:

Direct Reprogramming of Human Fibroblasts into Schwann Cells that Facilitate Regeneration of Injured Peripheral Nerve

Abstract:

Purpose�FSchwann cells (SCs) play pivotal roles in the maintenance and regeneration of the peripheral nervous system. Although transplantation of SCs enhances repair of experimentally damaged peripheral and central nerve tissues, it is difficult to prepare a sufficient number of functional SCs for transplantation therapy without causing adverse events for the donor.

Methods�FHere, we generated functional SCs by somatic cell reprogramming procedures and demonstrated their capability to promote peripheral nerve regeneration. Normal human fibroblasts were phenotypically converted into SCs by transducing SOX10 and Krox20genes followed by culturing for 10 days resulting in approximately 43% directly converted Schwann cells (dSCs).

Results�FThe dSCs expressed SC-specific proteins, secreted neurotrophic factors, and induced neuronal cells to extend neurites. The dSCs also displayed myelin-forming capability both in vitro and in vivo. Moreover, transplantation of the dSCs into the transected sciatic nerve in mice resulted in significantly accelerated regeneration of the nerve and in improved motor function at a level comparable to that with transplantation of the SCs obtained from a peripheral nerve.

Discussion�F Cell reprogramming technologies have great potential to provide a variety of tissue-specific cells for transplantation without causing severe adverse events to the donors from whom fibroblasts can be used for autografts or allografts.

Conclusion�FThe dSCs induced by our procedure may be applicable for novel regeneration therapy for not only peripheral nerve injury but also for central nerve damage and for neurodegenerative disorders related to SC dysfunction. 

Figure.1 The dSCs were induced in human dermal fibroblasts by transduction of two transcription factor genes normal human dermal fibroblasts were transduced with the S and/or K retroviral vectors and cultured in SC medium. (A) Immunostaining with the indicated schwann cell markers antibodies. pSCs were also stained as a control. (B) Representative phase contrast imaging of dSC (C) mRNA levels for the indicated genes were evaluated by realtime RTPCR. (D) GFP-transduced the dSCs were cocultured with neuronal cells, followed by staining with an anti-Tuj-1 antibody (gray) and with either anti-MBP antibody (red), which shows the dSCs can form myelin..

Figure.2 Transplanted directly converted Schwann cells significantly enhanced regeneration of an artificial peripheral nerve defect in mice. (A) Schematic view of an artificial peripheral nerve defect, tubulization, and cell transplantation. (B) Macroscopic views of the sciatic nerves are shown. Arrow-heads indicate stump anastomosis sites. (C) Nerve defect lesions were excised 8 weeks after the surgery, and transverse sections of the tissues were prepared. Myelin was stained with Luxol fast blue.