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

ID：MPS/DMR/BMAT（7623）1006552 PI：Naumann，Christoph ORG：印第安纳州/Purdue-IndianapolisTitle：弱粘附细胞在生物膜模拟细胞基质上的扩散和迁移智力优势：哺乳动物细胞迁移的中心范式表明，细胞运动是细胞功能的一个重要方面，是细胞因子诱导的突起和收缩力的结果，这些突起和收缩力通过特定的细胞连接（如基于整合素的局灶性粘附）传递到细胞环境中。 然而，与大多数哺乳动物细胞，这是很好地表征了这一范例，潜在的迁移过程中的弱粘附细胞与不太突出的细胞基质连接，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虫迁移，其特征在于相对快速的细胞体移位、增强的可塑性和明显的细胞形状波动。 当前的提案旨在通过使用新型生物膜模拟细胞基质来探索变形虫迁移的潜在过程，该基质允许细胞连接体的粘滞阻力系统性变化，而不允许形成承载张力的局灶性粘连。 通过改变细胞-基质连接的粘性阻力，以及通过使用药理学试剂选择性修改突出和收缩力，该实验系统将使PI能够确定变形虫迁移期间粘附、收缩和突出力之间的相互作用。 细胞连接体的粘性阻力的调节将使用固体支持物上的可调节双层数的多个聚合物系留的脂质双层的堆叠来完成。具体而言，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）细胞-细胞外基质（ECM）模拟整合素-层粘连蛋白连接（特异性目的1）和细胞-细胞模拟钙粘蛋白连接（特异性目的2）。细胞形态，细胞迁移速度，细胞形状的波动，和细胞骨架组织将使用互补的光学显微镜methods.BROADER IMPLEMENTS：建议的生物膜模仿细胞基质系统是一个强大的工具，探索了解不多的性能弱粘附细胞在良好的控制条件下。这些底物在生物医学细胞测定（包括药物筛选）中也具有相当大的翻译潜力，因为它们可以比目前现有的底物更真实地模拟天然组织环境。 生物传感器的应用也被设想，因为在多双层堆叠中，顶部双层和下面的固体之间的距离增加将可能改善膜蛋白的功能重建。“该项目的跨学科性质将为研究生和本科生提供良好的培训。 PI将继续致力于培养具有不同社会，种族和民族背景的广泛学生。 PI还将通过IUPUI纳米成像中心扩大高中一级的外联活动。 此外，该项目的研究成果将被开发成物理化学和仿生化学的本科和研究生课程。 研究还将通过科学会议、同行评审期刊以及互联网传播。

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.