Engineering composite materials to promote cell motility

描述（由申请人提供）：细胞迁移在正常的生物过程中起着关键作用，如发育模式，伤口愈合和免疫反应。同时，导致异常细胞迁移的突变是癌症转移等病理发展的基础。此外，在涉及生物材料植入物定植的医疗技术中，操纵细胞迁移是一个关键的设计考虑因素。天然细胞外基质蛋白的模块化构建激发了具有多个表位的合成生物材料的设计，这些表位可以协同促进细胞迁移。虽然表位如含有rgd的纤维连接蛋白（FN）的中心细胞结合域（CCBD）有效地介导细胞粘附，但在FN内的互补结构域如肝素结合域（HBD）显著增强CCBD介导的细胞扩散、膜延伸活性、局灶粘附（FA）的形成和局灶粘附激酶（FAK）的磷酸化。由于这些生物物理和生化事件是细胞迁移的组成部分，我们假设操纵生物材料上的CCBD和HBD的表面密度可能是调节细胞迁移速度的有效方法。重要的是，由于细胞迁移涉及这些中间过程的复杂协调，因此尚不清楚是否伴随的扩散、膜延伸活性、FA形成和生化信号的增强与细胞迁移的增强单调相关。因此，本研究的总体目标是阐明CCBD和HBD在促进细胞迁移方面的定量协同作用，具体目标如下：(1)设计一种新型基质，以表征良好的、可调的绝对量和相对量共同呈现CCBD和HBD；(2)量化细胞迁移速度对CCBD和HBD的依赖。研究结果将为设计促进细胞迁移的CCBD/HBD复合材料提供策略，用于涉及生物材料定植的医疗技术。

DESCRIPTION (provided by applicant): Cell migration plays a key role in normal biological processes such as developmental patterning, wound healing and immune response. Meanwhile, mutations that enable aberrant cell migration underpin the development of pathologies such as cancer metastasis. In addition, manipulating cell migration is a key design consideration in medical technologies that involve colonization of biomaterial implants. The modular construction of natural extracellular matrix proteins motivates the design of synthetic biomaterials presenting multiple epitopes that synergistically promote cell migration. While epitopes such as the RGD-containing, central cell-binding domain (CCBD) of fibronectin (FN) effectively mediate cell adhesion, complementing domains within FN such as the heparin-binding domain (HBD) significantly enhance CCBD-mediated cell spreading, membrane extension activity, focal adhesion (FA) formation and focal adhesion kinase (FAK) phosphorylation. Since these biophysical and biochemical events are integral elements of cell migration, we hypothesize that manipulating the surface density of CCBD and HBD on a biomaterial may be an effective method to tune cell migration speed. Importantly, because cell migration involves complex coordination of these intermediate processes, it is unclear whether concomitant enhancements in spreading, membrane extension activity, FA formation and biochemical signaling correlate monotonically to enhanced cell migration. Thus, the overall objective of the proposed work is to elucidate the quantitative synergy between CCBD and HBD in promoting cell migration, as outlined by the following Specific Aims: (1) to engineer a novel substratum for co-presenting CCBD and HBD in well-characterized, adjustable absolute and relative amounts, and (2) to quantify the dependence of cell migration speed on CCBD and HBD. Results from the proposed work will offer strategies for designing CCBD/HBD composite materials that promote cell migration for application in medical technologies involving colonization of biomaterials.