To stick or not to stick: Investigating cell adhesion dynamics and cell function using nanometric topography.

粘附或不粘附：使用纳米形貌研究细胞粘附动力学和细胞功能。

• 批准号: RGPIN-2014-06133
• 负责人: Hamilton, Douglas
• 金额: $ 2.55万
• 依托单位: University of Western Ontario
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=567614
• 关键词: stick; Investigating; cell; adhesion; dynamics

In organs and tissues of the human body, cells adhere to a complex scaffold-like protein mesh called the extracellular matrix (ECM). The ECM provides cells with many stimuli and signals that cells need to behave normally allowing tissues of the body to function. However, increasingly human cells contact artificial materials due to tissue damage and the use of biomaterials. Central in many bioengineering applications is the attachment of human cells to artificial materials, but the factors important in successful cell-material interactions are still not well understood, which limits the design of new functional biomaterials. Using techniques harnessed from the microelectronic industry, it became possible to produce structures with precisely defined surfaces for cell-biological studies, thus allowing the reaction of cells to defined topographic features to be observed. Our previous research described in the proposal has identified that the topography of a material can be altered to enhance cell attachment, movement and tissue development. When a cell attaches to a surface, it results in activation of important signaling molecules required by the cells to survive and function. Cells attach to surfaces through specialized sites called focal adhesions (FAs), and research is highlighting that these adhesions are very important sites in cells. FAs are not only responsible for relaying the attachment event to other areas within the cell, but they also mature to form fibrillar adhesions, which are sites where cells deposit and arrange the scaffold-like protein mesh (extracellular matrix). It is now known that not all cells possess the same ability to attach, and in the proposal we will compare two the response of two such cell types: dermal fibroblasts (skin) and gingival fibroblasts (gum tissue). Of particular relevance is that in healing of these tissues, gingival tissue heals without scar formation, but skin doesn’t. Despite decades of research, the mechanisms underlying these observations are still largely unknown, but altered adhesion is postulated to be important. Our aim in this proposal is to probe the differences in adhesion capacity of each cell type by altering the topography of the culture substrata at the nano- and micro-metric scale. Changes in substratum topography are a very powerful modulator of cell adhesion. Specifically we will: 1) quantify the influence of nanometric scale topographies on attachment, adhesion assembly and integrin recruitment in human gingival and dermal fibroblasts, and 2) assess how changes in focal and fibrillar adhesion formation by nanometric scale topographies alter intracellular signaling, proliferation, and gene expression in dermal and gingival fibroblasts. We anticipate that dermal and gingival fibroblasts will show significant differences in levels of adhesion to nanotopographies, which will result in altered patterns of signaling within the cells. Overall, we expect that topographies that increase gingival fibroblast adhesion will result in signaling patterns and gene expression associated with scarring and conversely, topographies which limit dermal fibroblast adhesion formation will induce a tissue remodeling phenotype. The results of the study will directly address how and cell adhesion turns external stimuli into signals that regulate cell behaviour, which will be important for all areas of cell biology. Furthermore, we anticipate that the information produced by our program could in the long term be used in cell and tissue engineering applications, where our lack of understanding of cell-material interactions are limiting the development of functional engineered tissue substitutes and the longevity of biomaterials.

在人体的器官和组织中，细胞粘附于称为细胞外基质（ECM）的复杂支架样蛋白质网。ECM为细胞提供了许多刺激和信号，细胞需要这些刺激和信号来正常运作，从而允许身体组织发挥功能。然而，由于组织损伤和生物材料的使用，越来越多的人类细胞接触人工材料。许多生物工程应用的核心是将人类细胞附着到人工材料上，但成功的细胞-材料相互作用的重要因素仍然没有很好地理解，这限制了新功能生物材料的设计。利用微电子工业的技术，可以生产具有精确定义的表面的结构，用于细胞生物学研究，从而允许观察细胞对定义的地形特征的反应。我们在提案中描述的先前研究已经确定，可以改变材料的形貌以增强细胞附着，运动和组织发育。当细胞附着在表面上时，它会激活细胞生存和发挥功能所需的重要信号分子。细胞通过称为粘着斑（FA）的专门位点附着在表面上，研究强调这些粘着斑是细胞中非常重要的位点。FA不仅负责将附着事件传递到细胞内的其他区域，而且它们还成熟形成纤维状粘附，这是细胞存款和排列支架样蛋白质网（细胞外基质）的位点。现在已知并非所有细胞都具有相同的附着能力，在该提案中，我们将比较两种细胞类型的反应：真皮成纤维细胞（皮肤）和牙龈成纤维细胞（牙龈组织）。特别相关的是，在这些组织的愈合中，牙龈组织愈合而不形成疤痕，但皮肤不会。尽管经过了数十年的研究，这些观察结果的机制仍然在很大程度上是未知的，但改变粘附被认为是重要的。我们的目的是在这个建议是探测在粘附能力的每种细胞类型的差异，通过改变在纳米和微米尺度的培养基质的地形。基质地形的变化是细胞粘附的一个非常强大的调节器。具体而言，我们将：1）量化纳米级形貌对人牙龈和真皮成纤维细胞中的附着、粘附组装和整合素募集的影响，和2）评估通过纳米级形貌的局灶性和纤维性粘附形成的变化如何改变真皮和牙龈成纤维细胞中的细胞内信号传导、增殖和基因表达。我们预计，皮肤和牙龈成纤维细胞将显示出显着差异的粘附水平的纳米形貌，这将导致改变模式的细胞内的信号。总体而言，我们预计增加牙龈成纤维细胞粘附的地形将导致与瘢痕形成相关的信号模式和基因表达，相反，限制真皮成纤维细胞粘附形成的地形将诱导组织重塑表型。该研究的结果将直接解决细胞粘附如何将外部刺激转化为调节细胞行为的信号，这对细胞生物学的所有领域都很重要。此外，我们预计，我们的计划产生的信息可以在长期内用于细胞和组织工程应用，我们缺乏对细胞-材料相互作用的理解，限制了功能性工程组织替代品的发展和生物材料的寿命。