Understanding how MSCs controllably remodel their environment

了解 MSC 如何可控地重塑其环境

• 批准号: 9099241
• 负责人: Kelly M Schultz
• 金额: $ 43.78万
• 依托单位: LEHIGH UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-06-01 至 2019-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9099241
• 关键词: Antibodies; Area; Biocompatible Materials; Cell physiology; Cell-Matrix Junction; Cells; Clear Cell; Cues; Data; Development; Diffusion; Encapsulated; Engineering; Environment; Enzymes; Evolution; Human; Hydrogels; In Situ; Inhibition of Matrix Metalloproteinases Pathway; Knowledge; Lead; Matrix Metalloproteinases; Measurement; Measures; Mediating; Mesenchymal Stem Cells; Microscopic; Modeling; Peptides; Physical environment; Play; Process; Property; Reaction; Recruitment Activity; Resolution; Role; Signal Transduction; Site; Source; Stem cells; Techniques; Testing; Time; Tissue Inhibitor of Metalloproteinase-1; Tissue Inhibitor of Metalloproteinases; Tissues; Traction; Video Microscopy; Work; Wound Healing; biodegradable polymer; cell motility; crosslink; density; design; environmental chemical; ethylene glycol; particle; public health relevance; scaffold

 DESCRIPTION: Cells do not simply reside within materials, they actively reengineer their microenvironments. The onset of cellular motility is characterized by dramatic degradation of the surrounding material due to attachment, traction and enzyme secretion. Just as cells modify their microenvironment, cells also receive cues from the material. The design of synthetic biomaterial scaffolds has aimed to recapitulate and harness this outside-in signaling to create materials that control cell motility. Understanding this phenomenon will advance the design of instructive materials that can spatially recruit and enhance encapsulated cell motility, the first steps in the wound healing process. The proposed work will use highly engineered matrix metalloproteinase (MMP) degradable poly(ethylene glycol)-peptide hydrogel microenvironments to encapsulate human mesenchymal stem cells (hMSCs) and high spatio-temporal-modulus resolution microrheological characterization to measure dynamic scaffold remodeling. These results will enhance the understanding of how cells interact with and remodel materials prior to and during motility. Previous work used microrheological characterization to quantify the scaffold microenvironment during remodeling, identifying the time-dependent and spatial rheological properties of the scaffold. The degradation gradient measured around the hMSC shows greatest degradation furthest from the cell with stiff scaffold remaining directly around the cell. This suggests that the cell is inhibiting MMP scaffold degradation. We hypothesize that cells are secreting tissue inhibitors of metalloproteinase (TIMPs) to inhibit scaffold degradation to allow for attachment and spreading prior to complete degradation and accelerated motility. The proposed work will investigate the role of TIMPs in the degradation and remodeling of a well defined hydrogel scaffold environment. Specific Aim 1 will determine the role of TIMPs in matrix remodeling during 3D hMSC motility. This will be done by neutralizing TIMPs and measuring the resulting scaffold degradation. Simple models will be used to describe the degradation profile around the cell and pinpoint the type of degradation reaction occurring in the scaffold. Specific Aim 2 will determine if the physical microenvironment changes the role of TIMPs in scaffold degradation and cellular motility. The scaffold stiffness will be varied and MPT will be used to measure hMSC degradation. It is expected that as the material becomes stiffer cell-mediated degradation will become more aggressive and less MMP inhibition will occur. Collectively, the proposed work will identify the role of TIMPs in scaffold degradation and cellular motility determining whether the neutralization of TIMPs will lead to more aggressive cell-mediated degradation, resulting in accelerated motility that can be harnessed to spatially recruit cells and enhance motility.

 描述：细胞并不简单地居住在材料中，它们积极地重新设计它们的微环境。细胞运动的开始的特征在于由于附着、牵引和酶分泌而引起的周围物质的急剧降解。就像细胞改变它们的微环境一样，细胞也会从材料中获得线索。合成生物材料支架的设计旨在概括和利用这种由外而内的信号传导来创造控制细胞运动的材料。了解这种现象将促进设计的教学材料，可以空间招募和增强封装的细胞运动，第一次 伤口愈合过程中的步骤。拟议的工作将使用高度工程化的基质金属蛋白酶（MMP）可降解的聚（乙二醇）-肽水凝胶微环境来封装人间充质干细胞（hMSCs）和高时空模量分辨率的微观流变学表征来测量动态支架重塑。这些结果将增强对细胞在运动之前和运动期间如何与材料相互作用和重塑材料的理解。先前的工作使用微观流变表征来量化重塑过程中的支架微环境，确定支架的时间依赖性和空间流变特性。在hMSC周围测量的降解梯度显示离细胞最远的降解最大，刚性支架直接保留在hMSC周围。 cell.这表明细胞抑制MMP支架降解。我们假设细胞分泌金属蛋白酶组织抑制剂（TIMPs），以抑制支架降解，从而在完全降解和加速运动之前允许附着和扩散。拟议的工作将研究TIMPs在明确定义的水凝胶支架环境的降解和重塑中的作用。具体目标1将确定TIMP在3D hMSC运动过程中基质重塑中的作用。这将通过中和TIMP和测量所得支架降解来完成。将使用简单的模型来描述细胞周围的降解情况，并确定细胞中发生的降解反应的类型。 脚手架具体目标2将确定物理微环境是否改变TIMP在支架降解和细胞运动中的作用。支架刚度将变化，并且MPT将用于测量hMSC降解。预计随着材料变得更硬，细胞介导的降解将变得更具侵略性，并且将发生更少的MMP抑制。总的来说，拟议的工作将确定TIMPs在支架降解和细胞运动中的作用，确定TIMPs的中和是否会导致更具侵略性的细胞介导的降解，从而加速运动，可以利用空间招募细胞和增强运动。