Spreading and Migration of Weakly Adhering Cells on Biomembrane-Mimicking Cell Substrates

ID：MPS/dmr/bmat(7623)1006552 PI：Naumann，Christoph ORG：Indiana/Purdue-Indianapolis标题：在模仿生物膜的细胞基质上弱黏附细胞的扩散和迁移INTELLECTUAL优点：哺乳动物细胞迁移的中心范式指出，细胞运动是细胞功能的一个重要方面，是细胞骨架诱导的突起和收缩力量通过特定的细胞连接，如基于整合素的焦点粘连传递到细胞环境的结果。然而，与大多数哺乳动物细胞不同的是，这种模式很好地描述了细胞的特征，弱附着的细胞与不那么显著的细胞底物联系的潜在的迁移过程，如白细胞和某些癌细胞，仍然难以捉摸。这种类型的迁移被称为变形体迁移，其特征是细胞体相对较快的移位，增强的可塑性，以及显著的细胞形状波动。目前的提议试图通过使用一种新型的模仿生物膜的细胞底物来探索阿米巴迁移的潜在过程，这种底物允许系统地改变细胞连接物的粘性阻力，而不允许形成张力携带的焦点粘连。通过改变细胞-底物连接的粘性阻力，以及使用药物选择性地修改突出力和收缩力，该实验系统将使PI能够确定阿米巴迁移过程中粘附力、收缩力和突出力之间的相互作用。细胞连接物的粘性阻力的调节将使用固体载体上的多个双分子层数目可调的聚合物系留类脂双层来完成。具体地说，PI建议在存在两种类型的细胞-底物连接的情况下进行迁移研究：(1)模仿整合素-层粘连蛋白连接的细胞-细胞外基质(ECM)(特定目标1)和模仿基于钙粘连蛋白的细胞-细胞连接(特定目标2)。将使用互补光学显微镜方法监测细胞形态、细胞迁移速度、细胞形状波动和细胞骨架组织。BROADER影响：建议的生物膜模拟细胞底物系统是一个强大的工具，可以在良好控制的条件下探索人们很少了解的弱附着细胞的特性。这些底物在生物医学细胞分析中也有很大的翻译潜力，包括药物筛选，因为它们可能比目前现有的底物更真实地模拟自然组织环境。生物传感器的应用也很有前景，因为在多双层堆栈中，增加顶层和底层固体之间的距离可能会改善膜蛋白的功能重建。该项目的跨学科特点将为研究生和本科生提供极好的培训。国际学生联合会将继续致力于培养一大批具有不同社会、种族和民族背景的学生。国际和平研究所还将扩大以前在高中开展的外联活动，并通过国际和平研究所纳米尺度成像中心开展活动。此外，该项目的研究成果将发展为物理化学和仿生化学的本科生和研究生课程。研究还将通过科学会议、同行评议的期刊以及互联网进行传播。

ID: MPS/DMR/BMAT(7623) 1006552 PI: Naumann, Christoph ORG: Indiana/Purdue-IndianapolisTitle: Spreading and Migration of Weakly Adhering Cells on Biomembrane-Mimicking Cell SubstratesINTELLECTUAL MERIT: The central paradigm of mammalian cell migration states that cell motility, which is an important aspect of cellular functionality, is the result of cytoskeleton-induced protrusion and contraction forces that are transduced to the cell environment through specific cell linkages, such as integrin-based focal adhesions. However, in contrast to most mammalian cells which are well characterized by this paradigm, the underlying migration processes of weakly adhering cells with less prominent cell substrate linkages, such as leukocytes and certain cancer cells, remain elusive. This type of migration is known as amoeboid migration and is characterized by relatively rapid cell body translocation, enhanced plasticity, and pronounced cellular shape fluctuations. The current proposal seeks to explore underlying processes of amoeboid migration by the use of a novel biomembrane-mimicking cell substrate that allows the systematic variation of viscous drag of cell linkers without permitting formation of tensile force-carrying focal adhesions. By varying the viscous drag of cell-substrate linkages, as well as by selective modification of protrusion and contraction forces using pharmacological agents, this experimental system will enable the PI to determine the interplay between adhesion, contraction, and protrusion forces during amoeboid migration. Tuning of the viscous drag of cell linkers will be accomplished using a stack of multiple polymer-tethered lipid bilayers of adjustable bilayer number on a solid support. Specifically, the PI proposes migration studies in the presence of two types of cell-substrate linkages: (1) cell-extracellular matrix (ECM) mimicking integrin-laminin linkages (Specific Aim 1) and cell-cell mimicking cadherin based linkages (Specific Aim 2). Cell morphologies, cell migration velocities, cellular shape fluctuations, and cytoskeletal organization will be monitored using complementary optical microscopy methods.BROADER IMPACTS: The proposed biomembrane-mimicking cell substrates system represents a powerful tool to explore poorly understood properties of weakly adhering cells under well-controlled conditions. These substrates also have substantial translational potential in biomedical cell assays, including drug screening, as they may mimic native tissue environments more realistically than currently existing substrates. Biosensor applications are also envisioned because the enhanced distance between top bilayer and underlying solid in multi-bilayer stacks will likely improve the functional reconstitution of membrane proteins. `The interdisciplinary character of the project will provide excellent training for graduate and undergraduate students. The PI will remain committed to the training of a broad pool of students with diverse social, racial, and ethnic backgrounds. The PI will also expand previous outreach activities at the high-school level and through the IUPUI Nanoscale Imaging Center. In addition, research results from this project will be developed into undergraduate and graduate courses in physical chemistry and biomimetic chemistry. Research will also be disseminated via scientific meetings, peer-reviewed journals, as well as via the internet.