2012年10月31日 讯 /生物谷BIOON/ --来自杜克大学医学中心的研究人员利用诱导性多能干细胞(iPSC)人工构建出软骨组织，而且还能成功地培养出这种组织，从而可能利用它进行组织修复，以及研究软骨损伤和骨关节炎。这一发现提示着iPSC可能一种重要的能够被用来构建出病人特异性的关节软骨组织的来源。相关研究结果于10月29日在线刊登在PNAS期刊上。
论文第一作者Brian O. Diekman说，“这种产生iPSC的技术是先获取成体干细胞，然后对它们进行转化而让它们具有胚胎干细胞的性质。”
在一项新的研究中，研究人员将在体外利用培养基培养的成年小鼠成纤维细胞重编程为iPSC，接着他们诱导iPSC分化为软骨细胞。他们同时对iPSC进行改造，从而让它们只在分化为软骨细胞时才表达绿色荧光蛋白(GFP)。当iPSC分化时，发生绿色荧光的软骨细胞很容易被鉴定出和从其他不想要的细胞中被分离开来。
这些经过改造的iPSC也产生更加大量的软骨组分，包括骨胶原，并且表现出天然软骨的特征性硬度，这就提示着它们将很可能能够修复体内的软骨缺陷。
Diekman说，“这是一个多步骤的方法：首先进行分化，然后进行分离，最后利用分离到的细胞构建组织。这项研究证实iPSC能够被用来制造出高质量的软骨来作为替换组织或者被用来研究疾病或开发出潜在的治疗方法。”
doi: 10.1073/pnas.1210422109
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Cartilage tissue engineering using differentiated and purified induced pluripotent stem cells
Brian O. Diekmana,b, Nicolas Christoforoub,c, Vincent P. Willarda, Haosi Suna,b, Johannah Sanchez-Adamsa, Kam W. Leongb, and Farshid Guilak
The development of regenerative therapies for cartilage injury has been greatly aided by recent advances in stem cell biology. Induced pluripotent stem cells (iPSCs) have the potential to provide an abundant cell source for tissue engineering, as well as generating patient-matched in vitro models to study genetic and environmental factors in cartilage repair and osteoarthritis. However, both cell therapy and modeling approaches require a purified and uniformly differentiated cell population to predictably recapitulate the physiological characteristics of cartilage. Here, iPSCs derived from adult mouse fibroblasts were chondrogenically differentiated and purified by type II collagen (Col2)-driven green fluorescent protein (GFP) expression. Col2 and aggrecan gene expression levels were significantly up-regulated in GFP+ cells compared with GFP− cells and decreased with monolayer expansion. An in vitro cartilage defect model was used to demonstrate integrative repair by GFP+ cells seeded in agarose, supporting their potential use in cartilage therapies. In chondrogenic pellet culture, cells synthesized cartilage-specific matrix as indicated by high levels of glycosaminoglycans and type II collagen and low levels of type I and type X collagen. The feasibility of cell expansion after initial differentiation was illustrated by homogenous matrix deposition in pellets from twice-passaged GFP+ cells. Finally, atomic force microscopy analysis showed increased microscale elastic moduli associated with collagen alignment at the periphery of pellets, mimicking zonal variation in native cartilage. This study demonstrates the potential use of iPSCs for cartilage defect repair and for creating tissue models of cartilage that can be matched to specific genetic backgrounds
