Engineering Multicellular Tissue Structure, Function and Vascularization

描述(由申请人提供)： 该项目重点研究细胞的空间组织和由此产生的细胞-细胞相互作用如何调节组织工程构建中稳定组织功能的发展和维持。在体内，通过旁分泌和旁分泌信号介导的细胞间的交流和合作是多细胞生命的标志，被认为在建立天然组织功能方面发挥着关键作用。由于组织内细胞的空间组织决定了哪些细胞类型之间存在哪些并列，这种结构最终可以决定组织工程构建最终是失败还是成功。不幸的是，目前几乎没有工具来操纵多细胞空间组织；因此，人们对组织结构对组织功能的真正影响知之甚少。该项目的长期目标是开发这样的细胞构图工具，利用它们来研究多细胞组织在调节组织功能中的作用，并探索如何利用这种组织来增强工程组织的功能。虽然将要开发的工具可以被认为是通用的，但研究人员将把重点放在血管工程化肝脏的开发上。研究人员最近开发了几种多细胞图案化工具，并用它们来证明肝细胞-基质细胞相互作用在支持肝细胞功能方面的重要性，以及实质和血管间室之间的相互作用在驱动血管生成方面的重要性。有趣的是，在这种情况下，几种细胞类型之间似乎存在相关的配对相互作用，并涉及可溶性旁分泌信号和通过钙粘附素参与的直接影响的组合。从这些早期的研究中可以明显看出，仔细的机制研究是必要的，以了解和了解这些多重相互作用将如何有助于肝脏结构的血管化和分化功能，从而可以开发出合理的策略来最终构建功能组织。有人建议，需要多方面的体外和体内努力，以开发必要的工具和研究，以实现这些目标。具体目标1将使用几种新的二维图案化工具来研究肝细胞、成纤维细胞和内皮细胞之间的细胞间相互作用在调节肝脏和血管生成功能中的作用。具体目标2将是研究三维结构中细胞的组织如何影响组织功能。具体目标3将探索多细胞组织在体内环境中参与调节组织整合和血管形成。除了产生图案化多细胞类型结构的新方法外，研究人员还将开发用于组织血管形成的非侵入性监测的纳米颗粒。该项目将导致对多细胞组织和细胞间通讯在稳定组织功能中的作用的全面理解，并为设计复杂的多细胞组织提供新的工具和策略。 公共卫生相关声明：该项目将开发工具，在工程肝脏结构中组织多种细胞类型，以最大限度地发挥组织功能，并与患者的血液供应整合。因此，这些研究将解决组织工程治疗疾病的几个主要障碍，否则只能通过整个器官移植来治愈这些疾病。

DESCRIPTION (provided by applicant): This project focuses on how the spatial organization of cells and resultant cell-cell interactions regulate the development and maintenance of stable tissue function within a tissue engineered construct. In vivo, cell-to cell communication and cooperation mediated through juxtacrine and paracrine signals is a hallmark of multicellular life, and is thought to play a critical role in the establishment of native tissue functions. Because the spatial organization of cells within tissues defines which juxtapositions exist between which cell types, this architecture ultimately can determine whether a tissue engineered construct ultimate will fail or succeed. Unfortunately, few tools currently exist to manipulate multicellular spatial organization; thus little is known about the true impact of tissue architecture to tissue function. The long-term goal of this project is to develop such cellular patterning tools, to use them to investigate the role of multicellular organization in regulating tissue function, and to explore how such organization can be used to enhance the function of engineered tissues. While the tools to be developed can be considered generic, the investigators will focus as a case study on the development of a vascularized engineered liver. The investigators have recently developed several multicellular patterning tools, and used them to demonstrate the importance of both hepatocyte-stromal cell interactions in supporting hepatocyte function, and interactions between parenchymal and vascular compartments in driving angiogenesis. Interestingly, there appear to be relevant pair wise interactions that occur between several cell types in this setting, and involve a combination of soluble paracrine signals and direct effects through cadherin engagement. It is apparent from these early studies that careful mechanistic studies are necessary to deconvolute and understand how these multiple interactions will contribute to the vascularization and differentiated function of the liver construct, so that a rational strategy can be developed to ultimately construct a functional tissue. It is proposed that a multifaceted in vitro and in vivo effort will be required to develop the necessary tools and studies to meet these goals. Specific Aim 1 will be to investigate the role of cell-cell interactions between hepatocytes, fibroblasts, and endothelial cells in regulating liver and angiogenic functions using several novel two-dimensional patterning tools. Specific Aim 2 will be to investigate how the organization of cells in three-dimensional constructs affects tissue function. Specific Aim 3 will be to explore the involvement of multicellular organization in regulating tissue integration and vascularization in an in vivo setting. In addition to novel approaches to generate patterned multi-cell type constructs, the investigators will also develop nanoparticles for non-invasive monitoring of tissue vascularization. This project will lead to an integrated understanding of the role of multicellular organization and cell-cell communication in stabilizing tissue function, and provide new tools and strategies to engineer complex multicellular tissues. Public Health Relevance Statement: This project will develop tools to organize multiple cell types within an engineered liver construct to maximize tissue function and integration with the patient's blood supply. As such, these studies will address several major hurdles towards the engineering of tissues for treating diseases that are otherwise only cured by whole organ transplantation.