Micropatterned scaffold-free liver tissue

描述(申请人提供)：严重缺乏功能性人体组织和器官替代品，使大多数器官衰竭患者无法进行临床移植。此外，研究和药物开发还需要健壮的人体模型。工程人造器官和组织可以为器官移植和体外系统提供替代或桥梁，用于药物开发或疾病建模。传统的基于生物材料和细胞外基质的组织工程面临一些挑战，如生物材料的不良宿主反应、支架降解产物释放的有毒物质以及细胞密度低等。无支架组织工程寻求仅从细胞及其分泌的基质(不使用聚合物和外源基质)创建致密的3D组织。迄今为止，这种多细胞无支架的“组织”是通过多种细胞类型的随机混合而产生的，任何组织都是细胞自组织的结果1-5。这些系统经常表现出高度可变的细胞形态发生(例如，可变的内皮细胞网络形成)以及组织核心的坏死。在无脚手架系统中，受控组装在很大程度上是未被探索的。事实上，组织工程学中一个中心悬而未决的问题是，工程师需要在多大程度上控制绝对结构而不是“哄骗”生物学，才能通过形态发生自组织成组织。我们假设，在工程化组织中预先确定的细胞空间组织将促进细胞组织和最大化组织功能，我们将其定义为“引导形态发生”。在这个方案中，我们将研究空间信号如何通过空间控制工程化无支架多细胞组织的初始结构来驱动细胞群落之间的紧急形态发生和组织组织。我们将开发一个平台来微模化3D多细胞无支架组织，然后研究预定义的组织结构如何决定组织功能和血管形态发生。我们将具体应用这些方法来研究3D多细胞组织结构的调节如何影响工程化无支架肝组织中分化的肝细胞功能和组织以及微血管的形态发生。这项工作的最终目标是开发能够研究3D组织发育和功能中空间控制的多细胞相互作用的平台，以便为工程肝组织建立建筑“设计规范”。我们预计，这些技术将极大地促进未来基于细胞的技术和工程组织的设计。) 公共卫生相关性：人工工程组织(例如肝脏)可以作为临床移植的器官替代品，也可以作为研究和药物开发的测试系统。在这里，我们将开发新的工程工具来研究大自然如何在构建三维组织中组织不同类型的“细胞积木”。这一知识可以应用于构建用于人类治疗的功能组织。)

DESCRIPTION (provided by applicant): Severe lack of functional human tissue and organ-substitutes precludes clinical transplantation for most patients suffering from organ failure. Additionally, robust human models are needed for research and pharmaceutical development. Engineered artificial organs and tissues could provide alternatives or bridges to organ transplant and in vitro systems for drug development or disease modeling. "Classical" biomaterial- and extracellular matrix-based tissue engineering faces several challenges, such as the unfavorable host response to biomaterials, toxic substances released by scaffold degradation products, and low cellular density. Scaffold- free tissue engineering seeks to create dense 3D tissues only from cells and the matrix they secrete (without the use of polymers and exogenous matrix). To date, such multi-cellular scaffold-free "tissues" have been created by random mixing of multiple cell types, and any organization has been the result of cellular self- organization1-5. These systems frequently exhibit highly variable cellular morphogenesis (e.g., variable endothelial cell network formation) as well as necrosis at the tissue core. Controlled assembly has been largely unexplored in scaffold-free systems. Indeed, a central unanswered question in tissue engineering is the degree to which engineers will need to control absolute architecture versus "coax" biology to self-organize into tissues via morphogenesis. We hypothesize that pre-determined spatial organization of cells within engineered tissues will facilitate cellular organization and maximize tissue function, which we define as "guided morphogenesis". In this proposal, we will study how spatial signals drive emergent morphogenesis and tissue organization between communities of cells by spatially controlling the initial architecture of engineered scaffold-free multi-cellular tissues. We will develop a platform to micropattern 3D multi-cellular scaffold-free tissues and then study how pre-defined tissue architecture dictates both tissue function and vascular morphogenesis. We will specifically apply these methods to study how modulation of 3D multi-cellular tissue architecture impacts differentiated hepatocyte function and organization as well as microvascular morphogenesis in engineered scaffold-free liver tissue. The ultimate objective of this work is to develop platforms that enable the study of spatially-controlled multicellular interactions in 3D tissue development and function in order to establish architectural "design specifications" for engineering liver tissue. We expect that such technologies will greatly facilitate the design of future cell-based technologies and engineered tissues. ) PUBLIC HEALTH RELEVANCE: Artificially engineered tissues (e.g., liver) could serve as organ-substitutes for clinical transplantation as well as test systems for research and pharmaceutical development. Here, we will develop novel engineering tools to study how nature organizes different types of "cellular building blocks" in building three-dimensional tissues. This knowledge could be applied in building functional tissues for human therapies. )