Biomaterials for local regulation of growth factor signaling

描述（由申请人提供）：可溶性生长因子在几乎所有组织发育和再生过程中起着至关重要的作用，诱导生长因子是许多新兴组织工程策略的关键组分。然而，用于设计生物材料的方法尚未实现在工程组织的开发期间对生长因子信号传导的高水平控制。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量配体，包括肽和寡核苷酸配体，特异性和可逆地螯合生长因子和生物材料内。我们假设，这些特定的，可变的亲和力相互作用将控制当地的生长因子的可用性，导致上调或下调生长因子的活性。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（FGF 2）对2维和3维培养环境中内皮细胞的影响。该信号系统对于所提出的研究是理想的，因为VEGF和FGF 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表征和显著的作用。此外，内皮细胞行为的调节对于需要高度调节的血管组织生长的临床应用（包括再生医学）具有重要意义。我们的具体目标是：2）表征非共价生长因子螯合和细胞粘附对生长因子信号传导的组合影响，进而体外内皮细胞的存活、增殖和组织化;和3）将生长因子螯合方法按比例放大到明确的水凝胶基质，并表征毛细血管形态发生和离体主动脉发芽期间受调节的生长因子信号传导。烷硫醇盐自组装单层基质和PEG水凝胶将用作初始模型生物材料，以解决指导该提案的假设。细胞和蛋白质与这些材料表现出很少或没有内在的相互作用，因此它们作为明确定义的模型系统来探索基于亲和力的生长因子调节。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“工程化”新组织的策略无法控制生长因子的作用，因此难以模拟组织发育并形成用于移植的功能组织。这项拟议的研究计划将开发一类新的材料，可用于控制生长因子在工程组织发育，特别是血管组织发育过程中的作用。

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.