Department of Biomedical Engineering, The University of Texas at Austin, 1 University Station, C0800, Austin, TX 78712-0238, USA.
Acta Biomater. 2010 Sep;6(9):3395-403. doi: 10.1016/j.actbio.2010.03.019. Epub 2010 Mar 17.
Microenvironmental cues are critical in regulating cell behavior and fate. The roles that matrix mechanical signals play in regulating cell behavior have recently been elucidated. An artificial matrix that can maintain the appropriate characteristics for transplanted stem cells is therefore needed to achieve a desired cell phenotype. The objective of this study was to develop a three-dimensional (3-D) matrix with tunable physical and mechanical properties and investigate their effects on mesenchymal stem cell (MSC) differentiation towards vascular cell types. In this study we developed an extracellular microenvironment by modifying fibrinogen with various polyethylene glycol (PEG) derivatives. We hypothesized that adjusting the type of PEG derivative to modify the resultant physical and mechanical characteristics of fibrin would allow us to create a tunable system for use in culture or in vivo in conjunction with a regenerative medicine strategy. Human MSC (hMSC) were entrapped into PEGylated fibrin matrices at a density of 50,000 cells ml(-1). Cell phenotypes were confirmed by immunofluorescent staining as well as the use of oligonucleotide arrays. Vascular phenotypes were correlated with measured mechanical properties and fiber diameters of the PEGylated fibrin matrices. Blocking studies were performed to identify mechanistic factors controlling MSC differentiation through selected blocking of matrix degradation or cell contraction. Cell-matrix interactions were also examined in vivo. Our results demonstrate that transdifferentiation of MSC towards an endothelial cell phenotype is profoundly affected by the 3-D matrix microenvironment. Our work provides a predictive road map for the creation of fibrin-based matrices that support robust endothelial cell gene expression and tubulogenesis.
微环境线索在调节细胞行为和命运方面起着至关重要的作用。最近已经阐明了基质机械信号在调节细胞行为中所起的作用。因此，需要一种能够维持移植干细胞适当特性的人工基质，以实现所需的细胞表型。本研究的目的是开发一种具有可调物理和机械性能的三维（3-D）基质，并研究其对间充质干细胞（MSC）向血管细胞类型分化的影响。在这项研究中，我们通过用各种聚乙二醇（PEG）衍生物修饰纤维蛋白原来构建细胞外微环境。我们假设，调整 PEG 衍生物的类型来调节纤维蛋白原的物理和机械特性，可以使我们创建一个可调节的系统，用于与再生医学策略相结合的培养或体内使用。人 MSC（hMSC）以 50,000 个细胞/ml 的密度包埋于 PEG 化纤维蛋白基质中。通过免疫荧光染色以及使用寡核苷酸阵列来确认细胞表型。将血管表型与测量的 PEG 化纤维蛋白基质的机械性能和纤维直径相关联。通过选择性阻断基质降解或细胞收缩来进行阻断研究，以确定控制 MSC 分化的机制因素。还在体内检查了细胞-基质相互作用。我们的结果表明，MSC 向内皮细胞表型的转分化受到 3-D 基质微环境的深刻影响。我们的工作为支持强大的内皮细胞基因表达和管状形成的纤维蛋白基基质的创建提供了一个预测路线图。
