Developing Biomaterial Scaffolds That Delay Senescence in Mesenchymal Stem Cells

描述（由申请人提供）：成体间充质干细胞（MSCs）具有巨大的再生治疗潜力，但在骨髓中发生的频率较低，在传统的体外组织扩增方法下缺乏连续分裂的能力，最终失去其分化潜力。这些因素限制了间充质干细胞治疗的临床疗效。扩大MSCs体外扩增潜力的最有希望的方法是在细胞外基质（ECM）蛋白上培养细胞，已知细胞与ECM之间的整合素配体结合可以激活细胞过程，如增殖、分化和存活。我们的目标是将已知的ECM/MSC相互作用在衰老过程中的作用转化为新一代支架设计，其中包含能够调节干细胞行为的适当化学信号和物理特征。在这项工作中，丝素蛋白将被用作一种生物材料支架，多种信号分子将被纳入其上。特异性靶点包括来自胶原蛋白的细胞粘附肽，以及在细胞分裂过程中激活端粒酶以延长端粒从而延长细胞寿命的因子。为了解耦和分离对MSCs衰老的影响，将对三维丝支架上肽显示的化学信号特性和密度进行独立优化。我们将深入研究这些修饰支架的化学和物理特性，以及在这些修饰的3D支架上扩增的MSCs的形态、生长速度、分化潜力和ECM蛋白的产生，并进行适当的对照。在这些支架上扩增的间充质干细胞的成骨标志物将被监测和比较，以将细胞行为的变化归因于基质组成。开发细胞培养支架的目标是延缓间充质干细胞的衰老，延长其增殖寿命，这将允许细胞在体外长期扩增，从而使间充质干细胞在广泛的细胞治疗和组织工程装置中得到临床应用。与公共卫生的相关性：成体间充质干细胞（MSCs）为骨、软骨、肌肉和韧带再生治疗提供了巨大的潜力，并且很容易从成体骨髓中获得，从而避免了胚胎干细胞的争议。因此，该项目旨在解决目前阻碍MSCs在细胞治疗和组织工程设备中使用的一些临床限制。具体来说，我们的目标是延缓体外培养MSCs的衰老过程。

DESCRIPTION (provided by applicant): Adult mesenchymal stem cells (MSCs) offer enormous potential for regenerative therapies, but occur in low frequency in bone marrow, lack the ability to continuously divide under traditional ex vivo tissue expansion methods and eventually lose their differentiation potential. These factors limit the clinical efficacy of MSC therapies. The most promising approach to extend the expansion potential of MSCs in vitro is the cultivation of cells on extracellular matrix (ECM) proteins, where integrin-ligand binding between cells and the ECM are known to activate cellular processes such as proliferation, differentiation, and survival. Our objectives are to translate what is known about the role of ECM/MSC interactions in the aging process into a new generation of scaffold designs containing the appropriate chemical signals and physical features capable of regulating stem cell behavior. For this work, silk fibroin proteins will be used as a biomaterial scaffold onto which a variety of signaling molecules will be incorporated. Specific targets include cell adhesion peptides derived from collagen, and factors that activate telomerase to extend telomeres during cell division thus prolonging the life span of the cell. The chemical signaling identity and density of the peptide displays on the 3D silk scaffolds will be optimized independently in order to decouple and isolate the effects on aging of MSCs. In depth chemical and physical characterization of these modified scaffolds, and the morphology, growth rate, differentiation potential, and production of ECM proteins by the MSCs expanded on these modified 3D scaffolds will be studied and quantified along with appropriate controls. Osteogenic markers of MSCs expanded on these scaffolds will be monitored and compared to ascribe changes in cell behavior to the matrix composition. The goal of developing cell culture scaffolds that can delay senescence of MSCs to prolong their proliferative lifetimes would allow for long-term expansion of the cells ex vivo, enabling clinical use of MSCs in a broad range of cell therapies and tissue-engineered devices. Relevance to public health: Adult mesenchymal stem cells (MSCs) offer enormous potential for bone, cartilage, muscle and ligament regenerative therapies, and are easily obtained from adult bone marrow which avoids the embryonic stem cell controversy. Therefore, this project aims to address some of the clinical limitations of MSCs that currently prevent their use in cell therapies and tissue-engineered devices. Specifically, our goals are to delay the aging process in MSCs cultured ex vivo.