RECODE: Defining Environmental Design Criteria for Directed Differentiation of Type 1 from Type 2 Lung Alveolar Epithelial Cells

正如最近的covid - 19大流行所证明的那样，肺部损伤可能会产生毁灭性的后果。然而，肺自我修复的细胞和分子机制仍然知之甚少。RECODE项目的目标是利用新颖和复杂的生物工程方法来更好地定义肺发育和修复的细胞和分子途径。该项目重点关注参与肺主要功能的细胞：为身体提供氧气的气体交换。这一信息将有助于开发新的可调生物材料来指导肺细胞的发育。RECODE项目的研究工作与教育和推广目标相结合，以促进生物医学工程和生物科学本科生的主动学习，制定推广计划，通过举办教育研讨会和海报会议，鼓励和激励当地高中科学、工程和数学科学学生。并在佛蒙特州、科罗拉多州和爱荷华州的每个参与地点向公众推广生物医学工程研究和教育。我们仍然迫切需要更好地了解肺发育和修复的基本细胞和分子机制，特别是肺泡上皮，这是气体交换的基本组成部分。目前的体外模型系统，包括类器官培养，已经提供了重要的信息，但不能完全再现天然组织结构或相关的环境影响，如细胞外基质（ECM）组成或刚度。RECODE项目的中心愿景是设计并验证一个强大的系统，以描述ECM组成和刚度调节肺泡2型上皮细胞（AT2s）向肺泡1型上皮细胞（AT1s）分化的机制。利用来自人类诱导多能干细胞（iAT2s）的AT2s，将开发复杂的组织工程方法，包括来自脱细胞人肺肺泡富集区（aECM）的水凝胶，以评估生理相关的ECM组成和硬度对AT2到AT1定向分化的影响。计算机建模将并行部署，以指导实证研究，并开发一个整体的差异化控制框架。这些方法将根据具体的定向目标进行评估：1)确定调节初级和iAT2干性并驱动AT1分化的特定ECM成分；2)研究动态可调微环境刚度对主要茎秆与at2茎秆和AT1分化的影响；3)利用基于主体的统计建模来预测成分和刚度对初级与iAT2到AT1分化的组合效应。这些独特和创新的方法涉及材料科学、肺再生医学、肺干细胞生物学和计算机建模的多学科和多机构结合。此外，所产生的范式和方法将对理解细胞- ecm相互作用在更广泛的器官系统中使细胞分化具有更广泛的影响和适用性。该RECODE项目由化学、生物工程、环境和运输系统部门的工程生物学和健康集群、刺激竞争研究的既定计划（EPSCoR）以及综合有机体系统部门的生理机制和生物力学计划和动物发育机制计划共同资助。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Injury to the lungs can have devastating consequences, as exemplified by the recent COVID19 pandemic. However, the cellular and molecular mechanisms by which the lung repairs itself remain poorly understood. The objective of this RECODE project is to utilize novel and sophisticated bioengineering approaches to better define cell and molecular pathways underlying lung development and repair. The project focuses on cells involved in the major function of the lung: gas exchange which provides oxygen to the body. This information will inform the development of new tunable biomaterials to guide lung cell development. The research efforts of this RECODE project are integrated with educational and outreach objectives to promote active learning in biomedical engineering and biologic sciences undergraduates, to develop outreach programs to encourage and inspire local high school science, engineering, and mathematical sciences students by hosting educational workshops poster sessions, and to promote biomedical engineering research and education towards the general public at each of the participating sites in Vermont, Colorado, and Iowa.There remains a critical need for better understanding of fundamental cellular and molecular mechanisms of lung development and repair, particularly with respect to the alveolar epithelium, a fundamental component of gas exchange. Current in vitro model systems, including organoid cultures, have provided important information but fail to fully reproduce native tissue structure or relevant environmental influences such as extracellular matrix (ECM) composition or stiffness. The central vision of this RECODE project is to devise and validate a robust system for delineating the mechanisms by which ECM composition and stiffness regulate differentiation of alveolar type 2 epithelial cells (AT2s) to alveolar type 1 epithelial cells (AT1s). Utilizing AT2s derived from human induced pluripotent stem cells (iAT2s), sophisticated tissue engineering approaches incorporating hydrogels derived from alveolar-enriched regions (aECM) of decellularized human lungs will be developed to evaluate effects of physiologically relevant ECM composition and stiffness on AT2 to AT1 directed differentiation. In silico modeling will be deployed in parallel to direct the empiric studies and to develop a holistic differentiation control framework. These approaches will be assessed in specific directed objectives: 1) To determine the specific ECM components regulating primary vs iAT2 stemness and driving AT1 differentiation; 2) To investigate the impact of dynamically tunable microenvironmental stiffness on primary vs iAT2 stemness and AT1 differentiation; and 3) To leverage agent-based and statistical modeling to predict combinatorial effects of composition and stiffness on primary vs iAT2 to AT1 differentiation. These unique and innovative approaches involve a multidisciplinary and multi-institutional combination of materials science, lung regenerative medicine, lung stem cell biology, and in silico modeling. Further, the paradigms and approaches generated will have broader impact and applicability to understanding cell-ECM interactions in enabling cell differentiation in a wider range of organ systems.This RECODE project is jointly funded by the Engineering Biology and Health Cluster in the Division of Chemical, Bioengineering, Environmental, and Transport Systems, the Established Program to Stimulate Competitive Research (EPSCoR), and the Physiological Mechanisms and Biomechanics Program and Animal Developmental Mechanisms Program in the Division of Integrative Organismal Systems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.