Engineering Mesenchymal Stem Cells for More Rapid Wound Healing

1066585道森智能优点：皮肤损伤会激活伤口愈合过程，这是一系列复杂的事件，包括炎症、肉芽组织的产生、再上皮化和疤痕组织的形成。生长因子在伤口愈合过程中起着至关重要的作用，伤口愈合过程从表皮损伤到瘢痕组织形成都是连续进行的。当伤口愈合过程在慢性炎症状态下停止时，老年患者和患有慢性病的患者会发展成慢性伤口。与慢性创面形成有关的两个因素是：(1)生长因子的产生受损；(2)血管生成减少。基于细胞的疗法，包括成纤维细胞和间充质干细胞(MSCs)，以前被用来促进更快的伤口愈合；然而，这些疗法的有效性受到伤口床中细胞迁移和植入较差的限制。建议的研究将集中在MSC在缠绕床中的迁移优化上。据推测，弥漫在创面床上的迁移的MSCs将有助于肉芽组织的形成，肉芽组织将收缩伤口，使伤口更快地闭合。改善的MSC迁移也可能改善生长因子的时空活性，因为它们将从遍布伤口组织的MSCs中分泌出来。血小板分泌的可溶性蛋白，如PDGF和转化生长因子β，介导了骨髓来源细胞向创伤组织的迁移，但这些蛋白对MSCs微观力学性质的影响却知之甚少。使用定量实时显微镜技术，包括颗粒跟踪微观流变学和延时荧光显微镜，将监测PDGF、转化生长因子β和/或低氧对细胞内流变学、细胞骨架组织和与细胞黏附分子相互作用的影响。体外跨井迁移研究将被用来测量选定刺激对MSC迁移的影响。这些技术将一起用于确定迁移性MSCs的机械和粘附性。优化的MSCs被发现具有与增加迁移相关的机械特性，将在体内测试在伤口床上的迁移。然后，将对MSCs进行基因工程，以表达血管内皮生长因子，该因子将用于促进更快的血管生成。这项拟议的研究将产生有关血小板分泌的可溶性蛋白对骨髓间充质干细胞的机械和黏附性能影响的基本信息。这些信息将被用于开发基于MSC的伤口愈合疗法。

1066585DawsonIntellectual Merit: Injury to the skin results in the activation of the wound healing process, a complex series of events that includes inflammation, production of granulation tissue, re-epithelialization, and scar tissue formation. Growth factors are essential in mediating the stages of wound healing, which proceed continuously from the time of epidermal damage to scar tissue formation. Elderly patients and patients suffering from chronic illness develop chronic wounds when the wound healing process is arrested in a state of chronic inflammation. Two of the factors that have been associated with the formation of chronic wounds are: (1) impaired production of growth factors and (2) reduced angiogensis. Cell-based therapies, including fibroblasts and mesenchymal stem cells (MSCs), have previously been used to promote more rapid wound healing; however, the effectiveness of these therapies was limited by poor cell migration and engraftment in the wound bed. The proposed studies will focus on the optimization of MSC migration in the wound bed. It is hypothesized that migrating MSCs that disseminate throughout the wound bed will contribute to the formation of granulation tissue, which will constrict the wound for more rapid wound closure. Improved MSC migration may also improve the spatio-temporal activity of the growth factors since they will be secreted from MSCs disseminated throughout the wound tissue. Platelet-secreted soluble proteins, such as PDGF and TGF-?Ò?¡, mediate the migration of bone marrow derived cells to wound tissues; however, little is known about the effects of these proteins on the microscopic mechanical properties of MSCs. Using quantitative real-time microscopy techniques, including particle tracking microrheology and time-lapsed fluorescent microscopy, the effects of PDGF, TGF-?Ò?¡, and/or hypoxia on intracellular rheology, cytoskeletal organization, and interaction with cell adhesion molecules will be monitored. In vitro transwell migration studies will be used to measure the effects of selected stimuli on MSC migration. Together these techniques will be used to determine the mechanical and adhesive properties of migratory MSCs. Optimized MSCs, found to possess the mechanical properties associated with increased migration, will be tested in vivo for migration in the wound bed. MSCs will then be genetically engineered to express vascular endothelial growth factor, which will be used to promote more rapid angiogenesis. The proposed studies will generate fundamental information about the effects of platelet secreted soluble proteins on the mechanical and adhesive properties of MSCs. This information will be utilized in the development of MSC-based therapies for wound healing.