毛囊干细胞

毛囊干细胞被认为是具慢周期性特点,但特定条件下具有较高增殖能力和克隆形成潜能的细胞。它们在形态学和生物化学上处于较原始的状态,常具有多潜能性。利用干细胞标记技术和克隆形成能力检测手段,人们发现毛囊干细胞主要存在于位于毛囊上半部的隆突部位。毛囊干细胞潜在的分子标记包括β1-整合素、α6-整合素、CD71、角蛋白19、p63和CD34,而在体内和体外它们的分子标记也不尽相同。毛囊隆突部位的干细胞能够分化成表皮、上皮性毛根鞘、发杆和皮脂腺。在个体发育过程中,它们具有分化成其他多种细胞系的能力。对于在毛发形态形成和生长周期中毛囊干细胞的行为,研究者们提出了多种假说,包括隆突激活假说和干细胞迁移假说。如今,毛囊干细胞主要应用于制备皮肤的代替品。     

毛囊干细胞及其隆突微环境

毛囊隆突(bulge)是毛囊干细胞特定的微环境,它维持并调节干细胞的特性,使干细胞在静息态、自我更新和分化上保持平衡。现重点从毛囊隆突的物理结构上来简要揭示微环境对干细胞的调控。     

毛囊干细胞在皮肤创伤修复中的促进作用

毛囊干细胞介导毛囊再生,近年研究发现毛囊干细胞在皮肤创伤修复中也发挥重要作用。文章通过对以毛囊干细胞为基础所进行的各种实验总结,揭示了毛囊干细胞可以促进毛囊再生,参与血管形成,皮肤浅表神经修复再生,皮肤附属器官重建以及皮肤表皮重建等过程,阐明了毛囊干细胞在皮肤损伤修复过程中的重要作用,同时阐明目前毛囊干细胞对皮肤创伤修复这一方向所面临的局限以及未来的发展前景。     

皮肤表皮干细胞的研究进展

成体的皮肤一生都在不断的自我更新,其中的毛囊还是保证毛发进行生长-脱落周期循环的细胞组织学基础。存在于表皮内的干细胞维持了成体皮肤的自我平衡及毛发再生。表皮是由构体分子组成。每个构体分子包含毛皮脂单位（毛囊和皮脂腺）及其周围的毛囊间表皮。毛囊间表皮具有祖细胞,损伤时能自我更新;毛囊具有多能干细胞,在新毛发周期开始或者损伤时能够启动干细胞功能,为毛囊的生长或表皮的修复提供细胞来源。本文概述了当前对表皮干细胞的认识,着重阐明毛囊间表皮内有祖细胞的证据,毛囊间表皮干细胞在体外的自我更新能力,毛囊膨突部内干细胞的特征和一些相关基因的表达等。     

神经干细胞研究进展

神经干细胞研究是当今生命科学研究的热点之一。神经干细胞是神经系统发育过程中保留下来的具有自我更新和多分化潜能的原始细胞。随着对神经干细胞认识的不断深入,其临床应用前景与价值得到了越来越多研究者的肯定。从神经干细胞的生物学特征、来源、培养鉴定、分化及应用等几个方面对目前的研究做一概述。     

胚胎干细胞模型的研究进展

胚胎干细胞是一种具有自我更新和多向分化潜能的细胞群,它的体外扩增、定向诱导分化在未来个体发育、基因和细胞治疗以及组织工程等方面的研究中具有不可估量的应用价值。简要回顾胚胎干细胞的研究进展和存在问题．对其未来的发展进行展望。     

EdU体外标记毛囊外根鞘干细胞的实验研究

摘要 目的：探寻一种简单有效的追踪定位毛囊干细胞的分裂增殖标记的方法,为后期毛囊干细胞增殖分化迁移机制的研究打下基础。方法：体外无菌条件下获取昆明乳鼠触须毛囊外根鞘,以5 % FCS+MEM作为基础培养液,添加4种不同浓度EdU（5-Ethynyl-2’-deoxyuridine）细胞标记物,进行毛囊外根鞘再生培养,冰冻切片,H.E染色,使用KeyFluor488对EdU所标记的再生细胞进行检测。结果：H.E染色和EdU标记染色结果发现EdU细胞标记物浓度越高,毛囊外根鞘再生形态越差,同时当EdU浓度为20 μ mol/L时,毛囊外根鞘增殖细胞标记效果是最好的。结论：EdU细胞标记物对毛囊外根鞘中的干细胞增殖活性具有一定的毒副作用,可能会影响细胞的正常生理代谢功能,浓度为20 μ mol/L EdU可以有效的标记毛囊干细胞增殖,并对毛囊再生结构影响较小。     

哺乳动物精原干细胞的研究进展

精原干细胞是雄性体内可以永久维持的成体干细胞,它具有自我更新和分化的能力,保证了雄性个体生命过程中精子发生的持续进行,从而实现将遗传信息传递给下一代。精原千细胞不仅可在体外实现长期培养或诱导分化为各级生精细胞,并且可在特定条件下将其诱导去分化成为多能性干细胞。同样,这种多能性干细胞如同胚胎干细胞,可被诱导形成造血细胞、神经元细胞、肌细胞等多种类型细胞。鉴于其独具的生物学特性,精原干细胞在揭示精子的发生机制、治疗雄性不育和转基因动物等研究中具有重要价值。该文对精原干细胞在生物学特性、纯化培养、移植、体外诱导分化及其相关调控方面的各项研究进行了小结,综述了近年来的研究历程和最新研究成果。     

视网膜干细胞的研究进展

干细胞研究是近年生命科学研究的热点之一,近来在干细胞研究领域的进步已经给治疗甚至是治愈某些变性疾病和不能治疗的人类疾病带来了希望.在体外,睫状缘色素上皮细胞来源的视网膜干细胞能增殖形成克隆球,并能分化成视网膜各种细胞类型,包括光感受器细胞,双极细胞及神经胶质细胞等等.视网膜干细胞的移植可以作为治疗一些致盲性眼病潜在治疗方式.因此,视网膜干细胞的研究对于视网膜变性疾病,如遗传性视网膜变性、青光眼、年龄相关性黄斑变性等,提供了新的治疗途径.现就视网膜干细胞的培养与鉴定,增殖、分化、移植以及信号机制方面的研究进展作一综述.     

Temporal Layering of Signaling Effectors Drives Chromatin Remodeling during Hair Follicle Stem Cell Lineage Progression

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Hair follicle-associated-pluripotent (HAP) stem cells

Various types of stem cells reside in the skin, including keratinocyte progenitor cells, melanocyte progenitor cells, skin-derived precursors (SKPs), and nestin-expressing hair follicle-associated-pluripotent (HAP) stem cells. HAP stem cells, located in the bulge area of the hair follicle, have been shown to differentiate to nerve cells, glial cells, keratinocytes, smooth muscle cells, cardiac muscle cells, and melanocytes. HAP stem cells are positive for the stem-cell marker CD34, as well as K15-negative, suggesting their relatively undifferentiated state. Therefore, HAP stem cells may be the most primitive stem cells in the skin. Moreover, HAP stem cells can regenerate the epidermis and at least parts of the hair follicle. These results suggest that HAP stem cells may be the origin of other stem cells in the skin. Transplanted HAP stem cells promote the recovery of peripheral-nerve and spinal-cord injuries and have the potential for heart regeneration as well. HAP stem cells are readily accessible from everyone, do not form tumors, and can be cryopreserved without loss of differentiation potential. These results suggest that HAP stem cells may have greater potential than iPS or ES cells for regenerative medicine.     

The Hair Follicle as an Interdisciplinary Model for Biomedical Research: An Eclectic Literature Synthesis

Skin is a comparatively accessible organ possessing many conserved regulatory and signaling pathways, drawing researchers from varied fields toward its study. Hair follicle (HF) biology in particular has expanded rapidly over the preceding decade, helping to shape and develop scientific knowledge across diverse areas of biomedical research, beyond the skin. The hope in compiling this review is to inspire more researchers to utilize the HF as an instructive biological model, bringing with them fresh perspectives and experience from differing fields of study. The authors also wish to further motivate seasoned hair researchers to explore the further reaches of their understanding and the discoveries yet to be made. For this reason, the authors have endeavored to collate an eclectic mix of some of the most thought-provoking and scientifically intriguing articles associated with the field of HF research, published in the preceding two years.     

诱导性多能干细胞向神经细胞分化的研究进展

诱导性多能干细胞(induced pluripotent stem cell,iPS cell)是通过转染外源特定的基因组合来诱导成体细胞重编程为类似于胚胎干细胞的一种多潜能干细胞,iPS细胞与胚胎干细胞不仅在形态上相似,而且在功能方面几乎相同.另外,iPS细胞的诞生克服了胚胎干细胞在临床应用时涉及的移植免疫排斥与伦理道德问题,因此具有重要的临床应用价值.目前iPS在治疗中枢神经系统性疾病方面的研究已取得很大进展,包括iPS细胞向神经细胞诱导分化方法的改进、分化机理的探索以及iPS细胞分化来源神经细胞在神经系统疾病模型中治疗作用的研究等.从iPS细胞的创建及特点、iPS细胞向神经细胞分化的诱导方法及研究新进展方面予以综述.     

Hair Follicle Development in Mouse Pluripotent Stem Cell-Derived Skin Organoids

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Human hair-follicle associated pluripotent (hHAP) stem cells differentiate to cardiac-muscle cells

We have previously demonstrated that nestin-expressing hair follicle-associated-pluripotent (HAP) stem cells are located in the bulge area. HAP stem cells have been previously shown to differentiate to neurons, glial cells, keratinocytes, smooth-muscle cells, melanocytes and cardiac-muscle cells in vitro. Subsequently, we demonstrated that HAP stem cells could effect nerve and spinal cord regeneration in mouse models, differentiating to Schwann cells and neurons. In previous studies, we established an efficient protocol for the differentiation of cardiac-muscle cells from mouse HAP stem cells. In the present study, we isolated the upper part of human hair follicles containing human HAP (hHAP) stem cells. The upper parts of human hair follicles were suspended in DMEM containing 10% FBS where they differentiated to cardiac-muscle cells as well as neurons, glial cells, keratinocytes and smooth-muscle cells. This method is appropriate for future use with human hair follicles to produce hHAP stem cells in sufficient quantities for future heart, nerve and spinal cord regeneration in the clinic.     

Wnt3a在毛囊及黑素细胞谱系中的表达

目的:探讨毛囊周期中,Wnt3a在毛囊及黑素细胞中的表达变化。方法:以DCT-LacZ转基因小鼠为动物模型,通过X-gal染色技术观察黑素细胞谱系在小鼠皮肤中的分布情况;采用X-gal染色结合免疫组化方法检测Wnt3a在毛囊及黑素细胞谱系中的表达情况;采用RT-PCR方法对小鼠皮肤全层Wnt3a和TYR的mRNA表达进行半定量分析。结果:在生长期毛囊中,Wnt3a蛋白在表皮、毛囊外根鞘Bulge区、内根鞘以及毛球部均有表达,在黑素干细胞与黑素细胞也观察到Wnt3a;在退化期,Wnt3a的表达逐渐减弱,仅在外根鞘有较弱的表达,但黑素干细胞中没有观察到Wnt3a;在静止期,几乎检测不到Wnt3a的表达;TYR mRNA与Wnt3a mRNA在毛囊周期中的表达模式一致,在生长期最强,退化期减弱,静止期最弱。结论:Wnt3a可能对黑素细胞谱系分化起到促进作用。