表皮干细胞多能性的确证及其在肌肉、神经组织损伤修复中的应用研究

It has been demonstrated that several types of somatic stem cells have the remarkable capacity to differentiate into other types of cells. Thus, stem cell-based therapy has been one of the best documented approaches in regenerative medicine, promising cures for a multitude of diseases and disorders. The skin is the largest organ of human body which is rich in epidermal stem cells (ESCs) in its basal layer. However, the promise of ESCs seems slim for generating nonepidermal tissues. Using our developed acclimatization induction strategy, we demonstrate the multipotency of adult human ESCs. The ESCs were isolated from the basal layer of adult human foreskin and cultured in Epilife medium, which allows for the growth of only keratin-positive keratinocytes, promotes high proliferation of ESCs, and prevents their differentiation. Induction of the ESCs by either serum or lineage-committed medium only produce differentiated epidermal cells. Hence, serum or lineage-committed medium was added to Epilife to acclimate ESCs to differentiate to other cell types. Unexpectedly, serum acclimatization can induce ESCs to produce a large number of smooth muscle cells and fewer of adipocytes and neurocytes within 3 weeks. In contrast, except for the terminally differentiated epidermal cells, committed acclimatization can induce ESCs to differentiate exclusively into the adipocytic, myogenic, or neurogenic lineages. These data indicate that human ESCs represent a novel multipotent adult stem cell, and suggest that they may provide an accessible, therapeutically promising cell source for regenerative medicine. In this study, it will further confirm the multipotency of ESCs, the function of muscle cells and neurocytes derived from inducing, and explore the therapeutic value of ESCs in muscle and neural tissue repair in vivo.

干细胞是创伤修复与组织再生的基础，目前发现的多种成体干细胞具有多潜能分化特征（可塑性），决定了其在疾病治疗、创伤修复与功能重建中重要的利用价值。皮肤是人体最大的器官，表皮基底层富含表皮干细胞，如果能证实其可塑性，将给组织再生与细胞治疗提供一种取材方便、来源广泛且含量丰富的新的干细胞源，但多年来，表皮干细胞一直被认为是一种只能分化为表皮细胞的单能性组织特异干细胞。近期，我们探索一种特定驯化诱导策略，将人包皮来源的基底层细胞分化为脂肪样细胞、肌肉样细胞以及神经样细胞，初步证实了人表皮干细胞的多潜能分化特征。本项目将进一步证实表皮干细胞的多向分化能力，并鉴定转分化细胞功能特征，进而探讨其在肌肉和神经组织损伤修复中的应用价值。

负责人在国家自然基金青年项目（项目编号：81201479，2013-2015年）的资助下，完成了表皮干细胞创面修复过程中多能性的研究。依托该课题体内外进一步确证表皮干细胞的多能性，并将其多能性与创面愈合相结合，证实该多能性是表皮干细胞促进创面愈合的机制之一，这与该课题设置的核心思想相吻合。同时，在此基础上，遵循创面修复研究热点进一步扩大研究，阐释糖尿病慢性创面的发生机制，初次证实慢性创面表皮干细胞的病理特征，细胞内氧化应激的聚集，通过ERK信号通路影响其正常的生理功能。同时，紧把生物治疗策略治疗慢性疾病的脉络，将外源性干细胞，即间充质干细胞引入急、慢性创面修复过程中，深入阐释其对创面愈合质量的改善，及对创面参与修复细胞功能的改进。负责人积极提升自身对科研的认识，融入了973,863（项目编号：2011AA020113；项目编号：2012CB518103）的研究团队，作为骨干积极参与项目研究。同时，参与多项国家重点项目及面上在研项目的研究工作。另外，参与四项由付小兵院士主持的临床新技术的研发、申报及答辩工作，依托该课题以第一作者发表SCI论文5篇。