Modeling Salivary Gland Fibrosis Using a Bioorthogonally Integrated Hydrogel Platform

我们认为唾液是理所当然的;没有它，我们将无法消化食物，保持牙齿卫生或正常说话。这就是许多头颈部癌症的幸存者和干燥综合征（一种特殊类型的自身免疫性疾病）患者每天所经历的：持续性口干。科学家们知道，口干通常与间质纤维蛋白的过度积累有关，这是组织纤维化的标志。然而，纤维化环境如何对腺泡细胞（唾液产生细胞）造成永久性损伤尚不清楚。该项目的目标是开发一个实验室生长的唾液腺组织模型，使用人工基质，采用高效的化学反应。从唾液腺分离的上皮细胞和从支持结缔组织分离的基质细胞将用于构建模型。该模型将由通过细胞-细胞识别保持在一起的球形上皮实体和分散在工程基质中的单个基质细胞组成。活组织将经历额外的化学转化以改变其组成和刚性，这将使健康的基质细胞转化为具有收缩组织和存款过量纤维蛋白的能力的异常细胞。我们将分析这些变化如何使上皮细胞停止产生唾液。使用工程组织模型，我们将评估治疗干预逆转纤维化和恢复分泌功能的潜力。与研究工作相结合的是一项教育计划，旨在吸引和增强职前幼儿教师的能力，他们将激励下一代科学家。一系列的实践展览、教学模块和创客实验室活动将为学生在材料科学和生物医学工程领域的职业生涯做好准备。技术描述尽管治疗策略取得了进展，但口干症（或口干）仍然是一种永久性和毁灭性的疾病，广泛影响头颈部恶性肿瘤或舍格伦综合征患者。虽然它是公认的分泌腺泡的损失是口干症的根本原因，有越来越多的证据表明，组织纤维化的重要性，促进和维持疾病。本申请利用了我们最近在生物正交化学、材料合成和组织工程方面的创新来构建具有整合的上皮细胞和间充质细胞的生理相关组织模型，从而允许原位扰动细胞外环境以模拟由于辐射损伤或异常免疫系统引起的唾液腺纤维化。所提出的模型将由多细胞上皮组装体和个体间充质干细胞在定制的合成基质中组成，其组成和性质可以动态调整以诱导纤维化。使用该模型，我们将研究正常间充质如何维持组织稳态，纤维化微环境如何改变上皮细胞的表型和组织，以及针对组织纤维化的治疗是否可以导致分泌功能的恢复。拟议的研究活动不仅将有助于下一代科学家和工程师的教育，而且还将增强幼儿教师的能力。协调一致的努力将致力于创造基于发现的教学方法，基于实验室的研究模块和基于社区的设计和创新活动。该奖项的设立体现了NSF的法定使命，通过基金会的学术价值评估和更广泛的影响力评估标准，被认为是值得支持的。

Non-technical descriptionWe take saliva for granted; without it, we will not be able to digest food, maintain dental hygiene or speak normally. This is what many survivors of head and neck cancers and patients with Sjögren’s syndrome, a particular type of autoimmune disease, experience every day: persistent dry mouth. Scientists know that dry mouth is often associated with over-accumulation of interstitial fibrous proteins, a hallmark of tissue fibrosis. However, how the fibrotic environment causes permanent damage to the acinar cells, the saliva producing cells, is not understood. The goal of this project is to develop a lab-grown salivary gland tissue model using artificial matrices created employing highly efficient chemical reactions. Epithelial cells isolated from salivary gland and stromal cells isolated from the supporting connective tissue will be used to build the model. The model will be comprised of spherical epithelial entities held together through cell-cell recognition and individual stromal cells dispersed in the engineered matrix. The living tissue will be subjected to additional chemical transformations to alter its makeup and rigidity, which will convert the healthy stromal cells to abnormal cells with the ability to contract the tissue and deposit excessive fibrous proteins. We will analyze how these changes make epithelial cells cease to produce saliva. Using the engineered tissue model, we will evaluate the potential of therapeutic interventions to reverse fibrosis and restore the secretory function. Integrated with the research effort is an educational plan to engage and empower pre-service, early childhood teachers who will inspire the next generation of scientists. A series of hands-on exhibits, teaching modules, and makers lab activities will be created to prepare students for careers in materials science and biomedical engineering.Technical description Despite advances in treatment strategies, xerostomia (or dry mouth) remains a permanent and devastating disease that broadly affects patients with head and neck malignancies or the Sjögren’s syndrome. Although it is well accepted that the loss of secretory acini is the root cause of xerostomia, there is accumulating evidence underlying the importance of tissue fibrosis in contributing to and sustaining the disease. This application capitalizes on our recent innovations in bioorthogonal chemistry, materials synthesis, and tissue engineering to construct a physiologically relevant tissue model with integrated epithelial and mesenchymal cells, allowing in situ perturbation of the extracellular environment to simulate salivary gland fibrosis due to radiation injury or an aberrant immune system. The proposed model will be comprised of multicellular epithelial assemblies and individual mesenchymal stem cells in a customized synthetic matrix, whose composition and properties can be dynamically tuned to induce fibrogenesis. Using this model, we will investigate how the normal mesenchyme maintains tissue homeostasis, how the fibrotic microenvironment alters the phenotype and organization of the epithelial cells, and whether therapies targeting tissue fibrosis can lead to the restoration of the secretory function. The proposed research activity will not only contribute to the education of the next generation of scientists and engineers, but also empower early childhood teachers. Concerted efforts will be dedicated to the creation of discovery-based teaching methods, lab-based research modules and community-based design and innovation activities. The interdisciplinary nature of the proposed research and educational efforts will also equip graduate students with up-to-date information, experimental skills, and creative thinking that are all indispensable in maintaining the United States’ global competitiveness.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.