Deconstructing the extracellular matrix: imaging 3D-bioprinted models to understand the effect of abnormal mechano-environment on collagen remodeling

生物组织并不是唯一由细胞组成的。它们体积的很大一部分是细胞外空间，这些空间主要由组成细胞外基质(ECM)的复杂的大分子网络填充。细胞外基质作为全身组织和器官的支架，对其结构和功能的完整性起着至关重要的作用。这项建议将组织工程(通过3D生物打印组织模型)与高分辨率成像相结合，为研究健康的ECM以及组织损伤后用纤维组织取代健康组织的异常过程提供了一个新的窗口。在提案的核心，我们将设计和设计组织来模拟损伤和修复。一旦受伤，恢复需要协调激活各种不同的修复途径，包括细胞外基质的改变。成纤维细胞是通过机械刺激(通过细胞外基质的改变)和化学刺激而分化为肌成纤维细胞的细胞。(Myo)成纤维细胞对组织修复是必不可少的；它们分泌胶原蛋白以生长新的ECM，受不断变化的物理化学环境的调节。然而，监管失调是很常见的。过多的疤痕组织反过来会影响(肌)成纤维细胞的微环境，导致修复被称为重塑的缺陷。这种扭曲的胶原蛋白的过度沉积最终会导致纤维化；各种组织过度生长、硬化和/或结疤。关键问题仍然没有答案：ECM和组织驻留细胞是如何相互作用的？细胞外基质重塑的机制是什么？解决这些根本问题将产生深远的后果；纤维化可能发生在许多组织中，包括肺、肝、心脏和脑，并且是包括某些癌症、动脉粥样硬化和哮喘在内的几种疾病的标志。这项研究计划的目标是揭示异常的物理化学环境如何影响细胞通讯反应。通过这样做，我们将对合成ECM模型开发和图像分析工具做出重大贡献；我们希望将定制的图像处理、机器学习和3D可视化工具应用到我们的多模式图像中，以揭示导致ECM缺陷修复的生物结构和反应。这一独特的跨学科研究项目涵盖了细胞生物学、机器学习、组织工程、光学成像和光谱学等主题。我们将开发和验证下一代3D肺组织模型；同时开发图像处理策略来表征工程化纤维网络将提供各种独特的HQP培训机会。成功将使我们处于战略地位，加强加拿大在新兴的组织工程和成像领域的存在。从长远来看，这项研究将指导为这种影响许多加拿大人生活的广泛、致命和其他无法治愈的疾病确定新的治疗靶点。

Biological tissues are not uniquely composed of cells. A substantial part of their volume is extracellular space, which is largely filled by an intricate network of macromolecules constituting the extracellular matrix (ECM). The ECM serves as the scaffolding for tissues and organs throughout the body, playing an essential role in their structural and functional integrity. This proposal combines tissue engineering (by 3D bioprinting tissue models) with high resolution imaging to provide a new window on healthy ECM, and on abnormal processes that replace healthy with fibrotic tissue following tissue injury. At the heart of the proposal, we will design and engineer tissues to model injury and repair. Upon injury, recovery requires the coordinated activation of a variety of different reparative pathways, including ECM alterations. Fibroblasts are cells thereby stimulated mechanically (via ECM changes) and chemically to undergo differentiation into myofibroblasts. (Myo)fibroblasts are essential to tissue repair; they secrete collagen to grow new ECM, regulated by the constantly changing physico-chemical environment. Dysregulation is common, however. Excessive scar tissue in turn affects the (myo)fibroblasts' micro-environment, leading to repair defects referred to as remodelling. This excessive deposition of distorted collagens ultimately causes fibrosis; the overgrowth, hardening, and/or scarring of various tissues. Key questions remain unanswered: How do the ECM and tissue-resident cells interact? What are the mechanisms that drive ECM remodeling? Addressing these fundamental questions would have far-reaching consequences; fibrosis can occur in many tissues including lungs, liver, heart, and brain, and is a hallmark of several diseases including certain cancers, atherosclerosis and asthma. The goal of this research proposal is to reveal how abnormal physico-chemical environments affect cellular communication responses. In so doing, we will contribution significantly to synthetic ECM model development and image analysis tools; we expect that application of customized image processing, machine learning, and 3D visualization tools to our multimodal images will reveal the biological structures and responses responsible for ECM defective repair. This unique, interdisciplinary research program spans cellular biology, machine learning, tissue engineering, optical imaging and spectroscopy themes. We will develop and validate next generation 3D lung tissue models; parallel development of image processing strategies to characterize engineered fibrotic networks will provide a variety of unique HQP training opportunities. Success will position us strategically to enhance the Canadian presence in the burgeoning field of tissue engineering and imaging. In the long term, this research will guide the identification of new therapeutic targets for this widespread, deadly, and otherwise incurable condition affecting the lives of many Canadians.