NIDCR Individual Predoctoral Dental Scientist Fellowship

描述(申请人提供)：伤口愈合是一个复杂的生物过程，需要多种细胞类型和动态细胞外基质(ECM)微环境在四个连续的阶段进行协调：止血、炎症、增殖和重塑。尽管对创面愈合的止血、炎症和一定程度上的增殖期已有较好的研究，但对创面重塑的调控却鲜有人关注。在血管重塑阶段，血管生成过程是完整的，抗血管生成机制在去除不必要的血管方面起着关键作用。血管退变与ECM重塑同时发生，ECM重塑是重组和强化基质组件以获得机械强度的过程。在大多数伤口中，伤口愈合的最终结果是疤痕形成，因为ECM永远不会完全恢复到正常结构。我们的长期目标是了解影响伤口愈合和疤痕形成的因素。我们实验室的初步研究表明，色素上皮衍生因子(PEDF)是调节重塑创面血管退行性变的重要内源性因子。最近的研究表明，PEDF也可能与内皮细胞(EC)以外的细胞类型有显著的相互作用，包括成纤维细胞。此外，PEDF的作用可能受到其与I型胶原、III型胶原和肝素等ECM分子结合的影响。目前的建议将探索PEDF影响伤口血管形成和瘢痕形成的机制。这一建议的中心假设是PEDF通过各种ECM结合伙伴来调节愈合过程中的血管退化和瘢痕形成。本研究的具体目的是1)确定PEDF对创面血管生成和瘢痕形成的影响，2)分析PEDF受体在创面中的分布，3)研究PEDF与其ECM结合伙伴在创面中的特异性功能相互作用。目的1对PEDF-/-小鼠的伤口愈合进行体内研究，以确定PEDF作为一种抗血管生成和ECM重塑因子的功能。在目标2中，免疫组织化学和间接免疫荧光研究将已知的PEDF受体定位于参与伤口愈合的主要细胞类型。目标3将涉及利用ECM-PEDF复合体的功能增益研究。这些研究将确定ECM结合的PEDF对伤口愈合结果的协同作用，包括血管生长和退化、ECM成熟、疤痕形成和伤口破裂强度。这些实验将为调节真皮伤口愈合的重塑阶段的机制提供洞察力，并可能为未来组织再生、纤维化和癌症的治疗提供建议。

DESCRIPTION (provided by applicant): Wound healing is a complex biological process that requires coordination among multiple cell types and the dynamic extracellular matrix (ECM) microenvironment in four sequential phases: hemostasis, inflammation, proliferation, and remodeling. Although the hemostatic, inflammatory, and to some extent the proliferative phases of wound healing have been well studied, the regulation of the remodeling phase has received less attention. In the remodeling phase, the angiogenic process is complete and anti-angiogenic mechanisms play a key role in removing unnecessary vessels. Vessel regression occurs simultaneously with ECM remodeling, a process that reorganizes and reinforces matrix components to achieve mechanical strength. In most wounds, the end result of wound healing is scar formation, as the ECM never fully returns to normal architecture. Our long term goal is to understand the factors that regulate wound resolution and scar formation. Preliminary studies in our lab demonstrate that pigment epithelium-derived factor (PEDF) is an important endogenous factor that regulates vascular regression in remodeling wounds. Recent studies suggest that PEDF may also have significant interactions with cell types other than endothelial cells (EC), including fibroblasts. Moreover, the effect of PEDF may be influenced by its binding to ECM molecules such as collagen I, collagen III, and heparin. The current proposal will explore the mechanisms by which PEDF influences wound vasculature and scar formation. The central hypothesis of this proposal is that PEDF works through various ECM binding partners to both regulate vessel regression and scar formation during healing. The specific aims of this study are 1) to determine the influence of PEDF on wound angiogenesis and scar formation, 2) to analyze the distribution of PEDF receptors in the wound, and 3) to investigate the specific functional interactions between PEDF and its ECM binding partners in wounds. Aim 1 will involve in vivo studies of wound healing in PEDF-/- mice to determine PEDF's function as an anti-angiogenic and ECM remodeling factor. In Aim 2, immunohistochemical and indirect immunofluorescence studies will localize known PEDF receptors to major cell types that are involved in wound healing. Aim 3 will involve gain-of-function studies utilizing ECM-PEDF complexes. These studies will determine the synergistic effect of ECM bound PEDF on wound healing outcomes, including blood vessel growth and regression, ECM maturation, scar formation, and wound breaking strength. These experiments will provide insight into the mechanisms that regulate the remodeling phase of dermal wound healing, and may suggest future therapeutic options for tissue regeneration, fibrosis and cancer.