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. Here, we present a novel direct conversion strategy for the generation of human SCPs, capable of differentiating into functional SCs. Easily 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. Highly 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. We 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.

中文翻译：

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直接诱导的人类雪旺氏细胞前体是雪旺氏细胞的宝贵来源。

雪旺氏细胞（SCs）主要负责周围神经系统（PNS）的再生和修复。可再生和谱系受限的SC前体（SCP）被认为是产生SC和研究SC谱系发育的高度希望和有希望的细胞来源，但是SCP非常有限。在这里，我们提出了一种新颖的直接转换策略，用于生成人类SCP，可以区分为功能性SC。使用游离载体（Oct3 / 4，Klf4，Sox2，L-Myc，Lin28和p53 shRNA），在SCP谱系特异性化学定义的中等条件下，将易于获得的人类皮肤成纤维细胞直接诱导为无整合SCP。进一步检查了诱导SCP（iSCP）分化为SC的能力。根据形态，谱系特异性标记，神经营养因子分泌和/或标准功能测定，可以确认iSCP和iSCP分化的SC（iSC）的鉴定和功能。在3周内从人皮肤成纤维细胞中产生了高纯度的iSCP的Sox 10阳性（纯度超过95％）。建立的iSCP可以在体外传播，同时保持其SCP身份。在1周内，iSCP可以有效地分化为SC（纯度超过95％）。iSC能够分泌各种神经营养因子，例如GDNF，NGF，BDNF和NT-3。通过使用小鼠背根神经节（DRG）神经元或人诱导的多能干细胞（iPSC）衍生的感觉神经元（HSNs）进行髓鞘共培养来评估iSC的体外髓鞘形成潜力。此外，在小鼠体内坐骨神经挤压伤模型中，iSC移植促进了坐骨神经修复并改善了行为恢复。我们报告了一种可靠的方法，可用于生成人类iSCP / iSC，可作为各种再生生物医学研究和应用（例如细胞疗法和药物发现，尤其是用于PNS损伤和疾病治疗）的有希望的细胞来源。