Engineering matrix-derived microcarriers as tissue-specific cell culture and delivery platforms

细胞行为受到微环境的高度影响，无论是在培养中还是在体内。在哺乳动物组织中，细胞存在于一个复杂的三维（3-D）系统中，该系统具有组织特异性的组成和结构。更具体地说，细胞反应是通过与细胞外基质（ECM）的动态相互作用介导的，细胞外基质是一个复杂的蛋白质和碳水化合物网络，调节组织的结构和功能。尽管已知微环境的重要性，但迄今为止绝大多数细胞培养研究都依赖于简化的模型系统，这些模型系统涉及在静态条件下在刚性二维塑料基质上生长。在这些系统中培养细胞可能会导致细胞反应的改变，这可能会影响这些模型的可靠性，从而理解细胞在生物体中的行为，这是干细胞研究、疾病建模和药物开发等应用所需要的。认识到对改进细胞培养模型的重大需求，Flynn博士的NSERC发现资助项目的重点是开发一系列用于哺乳动物细胞培养和组织工程的ecm衍生支架。在接下来的5年里，这笔拨款将支持5名研究生和5名本科生的培训，他们将开发组织特异性微载体，这些微载体来源于废弃脂肪、软骨和骨骼中的蛋白质，用作细胞培养和传递平台。这些球形微载体（直径小于0.5毫米）将被设计用于支持细胞附着和增殖。为了进一步调整细胞微环境，细胞种子微载体将在生物反应器系统中培养，这将允许仔细控制和监测细胞密度，搅拌速率和氧张力，这是细胞行为的重要调节因子。该团队将研究这项新技术的应用：i)组织特异性动态培养基质，用于指导从脂肪或骨髓中分离的成体干细胞的谱系特异性分化，以用于未来的细胞治疗应用；ii)研究培养中的成熟软骨细胞的平台；iii)构建用于模型系统或组织工程的3-D“微型组织”的构建模块。总的来说，这项研究将开发一个有前途和灵活的技术平台，使生物学研究人员能够更准确地模拟体内的细胞反应。此外，该项目将为干细胞、生物材料和组织工程等新兴多学科领域的下一代研究人员提供宝贵的培训机会。长期目标是将这项技术转化为加拿大的经济效益，并应用这些改进的文化模式来开发更有效的治疗方法，以提高加拿大人的生活质量。

Cellular behaviour is highly influenced by the microenvironment, both in culture and in the body. Within mammalian tissues, cells reside in a complex three-dimensional (3-D) system that has tissue-specific composition and architecture. More specifically, cell responses are mediated through dynamic interactions with the extracellular matrix (ECM), which is a complex network of proteins and carbohydrates that regulates the structure and function of tissues. Despite the known importance of the microenvironment, the vast majority of cell culture studies to date have relied on simplified model systems that involve growth on rigid two-dimensional plastic substrates under static conditions. Culturing cells within these systems can cause alterations in cellular responses that may impact the reliability of these models for understanding how cells behave within living organisms, which is needed for applications including stem cell research, disease modeling, and drug development. Recognizing the significant need for improved cell culture models, the focus of Dr. Flynn's NSERC Discovery Grant program is on the development of a range of ECM-derived scaffolds for use in mammalian cell culture and tissue engineering. Over the next 5 years, this grant will support the training of 5 graduate and 5 undergraduate students who will develop tissue-specific microcarriers derived from proteins sourced from discarded fat, cartilage, and bone for use as cell culture and delivery platforms. These spherical microcarriers (less than 0.5 mm in diameter) will be designed to support cell attachment and proliferation. To further tune the cellular microenvironment, the cell-seeded microcarriers will be cultured within bioreactor systems that will allow careful control and monitoring of the cell density, stirring rate, and oxygen tension, which are important regulators of cellular behaviour. The team will investigate the application of this new technology as: i) tissue-specific dynamic culture substrates for directing the lineage-specific differentiation of adult stem cells isolated from fat or bone marrow for future cell therapy applications, ii) platforms for studying mature cartilage cells in culture, and iii) building blocks for constructing 3-D “mini-tissues” for use as model systems or in tissue engineering. Overall, this research will develop a promising and flexible technology platform that may enable biological researchers to more accurately model cell responses within the body. Further, this program will provide invaluable training opportunities for the next generation of researchers in the emerging multidisciplinary fields of stem cells, biomaterials, and tissue engineering. The long-term goals are to translate this technology to be of economic benefit to Canada and to apply these improved culture models to develop more effective therapies to improve the quality of life of Canadians.