Engineering Multicellular Tissue Structure, Function, and Vascularization

 描述：该项目的目标是确定工程化肝组织中的多细胞相互作用，使其能够在活体宿主体内植入和扩张。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，并被认为在天然组织的建立中起着关键作用 功能。特别是在肝脏中，这种相互作用似乎对组织功能和再生至关重要。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。 在过去四年的合作项目中，研究人员表明，生物材料可以用于支持由随机组织的人肝细胞、内皮细胞和基质细胞组成的人类工程化人工肝的移植和腹膜植入。然后，通过使用新的微技术工具在3D环境中控制这些细胞类型的组织，该团队已经表明，架构既影响肝细胞的分化状态，也影响移植的移植物的功能。此外， 研究人员已经开发了生物打印工具来在这些3D水凝胶中建立血管网络，并证明了这些工具可以提高共包埋肝细胞的存活率，以及预防肝组织堵塞从而加速腹膜植入的方法。在这些模型系统中，我们观察到存在通过旁分泌信号的相互作用-即内皮细胞影响肝细胞功能，反过来，肝细胞影响内皮细胞网络。有趣的是，许多旁分泌信号与网络的灌注量相关，因为它们要么受剪应力、缺氧的调节，要么两者兼而有之。在目前的应用中，研究人员试图确定工程化肝脏对旁分泌信号和灌流的空间依赖性，从而有效地允许它们在刺激下植入和扩张。本次竞争性更新的具体目的是：(1)明确3D定位在体内和体外肝细胞和内皮细胞之间旁分泌信号中的作用；(2)了解3D构建体和体内3D构建物中网络灌流对细胞功能的影响；(3)评估网络结构和灌流对体内移植物扩张的功能作用。该项目将导致对多细胞组织和细胞间通讯在稳定肝组织血管形成和功能方面的作用的全面理解，并为更广泛的社区提供新的工具和策略来设计复杂的多细胞组织。

 DESCRIPTION: The goal of this project is to define multicellular interactions in engineered hepatic tissue that will enable its engraftment and expansion in a living host. In vivo, cell-to-cel 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. Specifically in liver, such interactions appear to be critical for tissue function and regeneration. Unfortunately, few tools currently exist to manipulate multicellular spatial organization; thus little is known about the true impact of tissue architecture to tissue function. During the past 4 years of this collaborative project, the investigators have shown that biomaterials can be used to support the transplantation and peritoneal engraftment of human engineered artificial livers composed of randomly- organized human hepatocytes, endothelial cells and stromal cells. Then, by using novel microtechnology tools to control the organization of these cell types within a 3D context, the team has shown that architecture impacts both the differentiated state of the hepatocyte and the function of the transplanted graft. In addition, the investigators have developed bioprinting tools to build vascular networks in these 3D hydrogels and demonstrated that these improve the survival of co-embedded hepatocytes as well as methods to prevacularize hepatic tissues and thereby accelerate the peritoneal engraftment. In these model systems, we observe that there is a reciprocal interaction via paracrine signals- that is endothelial cells impact hepatocyte function and conversely that hepatocytes impact the endothelial network. Interestingly, many of the paracrine signals are interrelated with perfusion of the network as they are regulated either by shear stress, hypoxia or both. In the current application, the investigators seek to define the spatial dependence on paracrine signaling and perfusion within engineered livers that would efficiently allow them to engraft and expand upon stimulation. The specific aims of this competitive renewal are: (1) To define the role of 3D positioning on paracrine signaling between hepatocytes and endothelial cells in vitro and in vivo, (2) To understand the role of network perfusion on cell function in 3D constructs in vitro and in vivo, and (3) To assess the functional role of network architecture and perfusion on graft expansion in vivo. This project will lead to an integrated understanding of the role of multicellulr organization and cell-cell communication in stabilizing hepatic tissue vascularization and function, and provide new tools and strategies to the broader community to engineer complex multicellular tissues.