亚全能干细胞向肝细胞样细胞诱导分化

发布时间：2018-04-02 15:29

本文选题：成人　切入点：脂肪　出处：《中国协和医科大学》2006年硕士论文

【摘要】：干细胞可塑性，即来源于某一组织的干细胞可以分化为其他组织类型的细胞，已经成为生命科学领域内一新的研究热点，但对干细胞可塑性机制的认识，学术界仍存在有较大的争议。最近的研究提示成体组织中存在多能干细胞。我们认为在多种成体组织中都存在一类原始干细胞群体，它们和造血干细胞、神经干细胞等多能干细胞不同，后者只能分化为特定胚层的细胞，而这类原始干细胞可分化为不同胚层的组织细胞；另一方面，它们区别于胚胎干细胞，在个体生长发育过程中逐渐失去部分分化潜能，并且会出现一些特殊表型或者分子标志，我们称其为成体亚全能干细胞，这类干细胞具有下列特性：可分化为不同胚层的细胞，分布于身体的几乎所有组织和器官，具有相同的表型或标志；他们在胚胎期存在于一些或全部的组织和器官中，可分化为不同类型的多能干细胞并在生长发育和新陈代谢中维持这些多能干细胞保持平衡：可以参与机体自我修复和更新，不仅能分化为所在器官的组织特异性细胞，参与器官重塑，也可以在炎症因子或者生长因子的趋化作用下，远处转移修复受损组织。显而易见出，成体亚全能干细胞具有的这些特性无论是在干细胞参与组织损伤修复或是解决在实际应用中干细胞数量不足上都具有重要的意义。因此，对于研究发育生物学而言，能够分离纯化、培养和有效利用成体亚全能干细胞，无疑具有非常重要的意义。另外，这一细胞亚群很可能成为组织工程中理想的种子细胞，用于治疗一些遗传及退行性疾病。本研究的第一部分旨在研究成体脂肪来源的干细胞具有向不同胚层细胞分化的能力。通过运用Flk1、CD31及CD34免疫磁珠分选和极限稀释法，从成体脂肪中得到Flk1~+CD31~-CD34~-的多能干细胞亚群，免疫表型与骨髓源Flk1~+CD31~-CD34~-多能干细胞的表型一致；体外可被定向诱导为在细胞形态及表型上与脂肪细胞、成骨细胞、神经细胞、肠上皮细胞一致的细胞。因此，，以上结果提示在成人的脂肪组织中确实存有一类我们所称的亚全能干细胞。在第二部分，我们研究了成人骨髓、成人脂肪和胎儿小肠来源的干细胞体外向肝细胞分化的能力。首先，根据目前报道的几种诱导体系：HGF+FGF-4，HGF+OSM，
[Abstract]:Stem cell plasticity, that is, stem cells derived from one tissue can differentiate into other tissue types, has become a new research hotspot in the field of life science, but the understanding of stem cell plasticity mechanism.There is still a great deal of controversy in academia.Recent studies have suggested the presence of pluripotent stem cells in adult tissues.We think there is a group of primitive stem cells in a variety of adult tissues, which are different from pluripotent stem cells such as hematopoietic stem cells and neural stem cells, which can only differentiate into specific embryonic cells.These primitive stem cells, on the other hand, can differentiate into histocytes of different endosperms; on the other hand, they differ from embryonic stem cells in that they gradually lose some of their differentiation potential during individual growth and development, and exhibit specific phenotypic or molecular markers.We call them adult sub-totipotent stem cells, which have the following characteristics: they can differentiate into cells of different embryonic layers, distribute in almost all tissues and organs of the body, and have the same phenotype or marker;They exist in some or all of the tissues and organs at the embryonic stage, can differentiate into different types of pluripotent stem cells and maintain a balance between growth, development and metabolism: they can participate in the body's self-repair and renewal.It can not only differentiate into the specific cells of the organ, participate in organ remodeling, but also repair the damaged tissue by distant metastasis under the chemotaxis of inflammatory or growth factors.It is obvious that these characteristics of adult subtotipotent stem cells are of great significance whether they are involved in the repair of tissue damage or in solving the shortage of stem cells in practical applications.Therefore, for the study of developmental biology, it is of great significance to be able to isolate, purify, culture and effectively utilize adult sub-totipotent stem cells.In addition, this subgroup is likely to be an ideal seed cell in tissue engineering for the treatment of some genetic and degenerative diseases.The first part of this study was to study the ability of stem cells derived from adult adipose cells to differentiate into different embryonic layer cells.By using Flk1T CD31 and CD34 immunomagnetic beads sorting and limiting dilution method, Flk1 ~ CD31- CD34- subsets of pluripotent stem cells were obtained from adult fat. The immunophenotype was consistent with that of bone marrow-derived Flk1 ~ CD31 ~ CD31- CD34- multipotent stem cells.In vitro, the cells can be induced to be identical with adipocytes, osteoblasts, nerve cells and intestinal epithelial cells in morphology and phenotype.Therefore, these results suggest that there is what we call subpotent stem cells in adult adipose tissue.In the second part, we studied the ability of stem cells derived from adult bone marrow, adult fat and fetal small intestine to differentiate into hepatocytes in vitro.First of all, according to several kinds of induction systems reported at present, 1: HGF FGF-4 HGF OSM.
【学位授予单位】：中国协和医科大学
【学位级别】：硕士
【学位授予年份】：2006
【分类号】：R329.2

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