Biomaterials for local regulation of growth factor signaling

描述(申请人提供)：可溶性生长因子在几乎所有的组织发育和再生过程中起着至关重要的作用，而诱导性生长因子是许多新兴组织工程策略的关键组成部分。然而，用于设计生物材料的方法还没有在工程化组织的发展过程中实现对生长因子信号的高水平控制。我们建议开发一类新的生物材料，能够局部调节生长因子信号。我们的方法使用低分子配体，包括肽和寡核苷酸配体，特异性地和可逆地将生长因子隔离在生物材料上和材料内。我们假设，这些特定的、可变的亲和力相互作用将控制局部生长因子的可获得性，导致上调或下调生长因子活性。这种方法最初将用于调节血管内皮生长因子(VEGF)和成纤维细胞生长因子-2(FGF2)在二维和三维培养环境中对内皮细胞的影响。由于血管内皮生长因子和成纤维细胞生长因子2在体外和体内对内皮细胞的存活、增殖和分化功能具有良好的特征和显著的影响，因此该信号系统是所提出的研究的理想选择。此外，对血管内皮细胞行为的调控对于需要高度调控血管组织生长的临床应用具有重要意义，包括再生医学。我们的具体目标是：1)开发和表征定制的细胞培养底物，用于局部、可控地隔离FGF2和VEGF；2)表征非共价生长因子隔离和细胞黏附对生长因子信号转导的组合影响，进而影响体外培养内皮细胞的存活、增殖和组织；3)将生长因子隔离方法扩展到定义明确的水凝胶基质，并表征毛细血管形态形成和体外主动脉萌发过程中受调控的生长因子信号转导。硫代烷基自组装单层底物和聚乙二醇水凝胶将被用作初始模型生物材料，以解决指导这一提议的假说。细胞和蛋白质很少或根本没有与这些物质的内在相互作用，因此它们是探索基于亲和力的生长因子调控的明确定义的模型系统。我们预计，所提出的方法最终可以应用于广泛的常见生物材料，并可能代表生物材料设计的一个新方向。所有组织类型的发育都需要称为生长因子的特定蛋白质的协调作用。目前试图“设计”新组织的策略无法控制生长因子的影响，因此很难模仿组织发育并形成可用于移植的功能组织。这项拟议的研究计划将开发一种新的材料，可用于在工程化组织发育，特别是血管组织发育过程中控制生长因子的影响。

DESCRIPTION (provided by applicant): Soluble growth factors play a vital role in virtually all tissue development and regeneration processes, and inductive growth factors are critical components of many emerging tissue engineering strategies. However, approaches used to design biomaterials have not yet achieved a high level of control over growth factor signaling during development of engineered tissues. We propose to develop a new class of biomaterials capable of locally regulating growth factor signaling. Our approach uses low molecular weight ligands, including peptide and oligonucleotide ligands, to specifically and reversibly sequester growth factors upon and within biomaterials. We hypothesize that these specific, variable affinity interactions will control local growth factor availability, resulting in up- or down-regulated growth factor activity. This approach will initially be used to regulate the effects of vascular endothelial growth factor (VEGF) and fibroblast growth factor-2 (FGF2) on endothelial cells in 2-dimensional and 3-dimensional culture environments. This signaling system is ideal for the proposed studies, as VEGF and FGF2 have well-characterized and pronounced effects on survival, proliferation, and differentiated function of endothelial cells in vitro and in vivo. Furthermore, regulation of endothelial cell behavior has significant implications for clinical applications that require highly regulated vascular tissue growth, including regenerative medicine. We specifically aim to: 1) develop and characterize tailored cell culture substrates for localized, controlled sequestering of FGF2 and VEGF; 2) characterize the combinatorial influence of non-covalent growth factor sequestering and cell adhesion on growth factor signaling and, in turn, survival, proliferation, and organization of endothelial cells in vitro; and 3) scale the growth factor sequestering approach to a well-defined hydrogel matrix, and characterize regulated growth factor signaling during capillary morphogenesis and ex vivo aortic sprouting. Alkanethiolate self-assembled monolayer substrates and PEG hydrogels will be used as initial model biomaterials to address the hypothesis guiding this proposal. Cells and proteins exhibit little or no intrinsic interaction with these materials, and they therefore serve as well-defined model systems to explore affinity- based growth factor regulation. We anticipate that the proposed approach can ultimately be applied to a broad range of common biomaterials, and may represent a new direction in biomaterials design. Development of all tissue types requires the coordinated action of particular proteins called growth factors. Current strategies that attempt to "engineer" new tissues are unable to control the effects of growth factors, and it is therefore difficult to mimic tissue development and form functional tissues for transplantation. This proposed research program will develop a new class of materials that can be used to control the effects of growth factors during engineered tissue development, particularly vascular tissue development.