Repair, Regeneration and Fibrosis of the Salivary Gland

 描述（由申请人提供）：伴随疾病状态的唾液腺功能障碍在美国和世界范围内造成了巨大的健康和经济负担。头颈癌放射治疗和自身免疫性疾病舍格伦综合征（SS）的衰弱后果可以通过有效的策略来改善，以再生功能性唾液上皮细胞并防止纤维化的发展。这项探索性R21提案的目标是产生关于唾液腺修复和预防疾病相关纤维化的新知识。我们的初步研究确定了SMG上皮内富含波形蛋白的细胞的新亚群。这些细胞在损伤后进行扩增，并在伤口修复中发挥作用。它们非常类似于介导损伤修复的透镜上皮细胞内的中胚层谱系的富含波形蛋白的修复细胞祖细胞， 并且其消融导致上皮的无效修复。重要的是，当这些修复细胞遇到损伤组织特有的刚性细胞外基质环境时，它们可以分化成引起纤维化疾病的肌成纤维细胞。由于唾液腺疾病导致结构缺陷，它们可能触发修复过程，包括激活这些富含维门汀的修复细胞。在这个提议中，我们的目标是表征SMG修复细胞，并阐明它们在SMG修复中的作用，包括它们在愈合过程完成时获得肌成纤维细胞表型的能力。我们的假设是，修复细胞祖细胞中的中胚层谱系的SMG功能作为立即响应损伤，他们介导有效的伤口修复，他们的命运包括消除细胞凋亡和分化成肌成纤维细胞。我们将使用转基因小鼠的遗传谱系追踪来验证这一假设，转基因小鼠在内源性波形蛋白启动子的控制下表达他莫昔芬诱导型CreER，再加上离体和体内SMG损伤模型。提出了两个目标：1）研究SMG修复细胞的谱系，它们对损伤的反应，以及对其修复功能至关重要的细胞信号传导和细胞骨架功能;和2）确定伤口愈合后修复细胞的命运，我们提出的研究是重要的和创新的，因为他们将确定SMG修复细胞的身份，并探索这些间充质细胞是否可以可能有助于唾液组织再生此外，我们将获得如何操纵这些修复细胞以防止唾液腺纤维化疾病发展的知识。我们的研究结果有可能转化为唾液腺结构和功能再生的有效治疗方法，以及组织损伤修复和再生领域。

 DESCRIPTION (provided by applicant): Salivary gland dysfunctions that accompany disease states pose a substantial health and economic burden in the US and worldwide. The debilitating consequences of radiation treatment for head and neck cancer, and of the autoimmune disorder Sjögren's Syndrome (SS), could be ameliorated with effective strategies to regenerate functional salivary epithelia and to prevent the development of fibrosis. The goal of this exploratory R21 proposal is to generate new knowledge about salivary gland repair and prevention of disease-associated fibrosis. Our preliminary studies identified a novel subpopulation of vimentin-rich cells within the SMG epithelia. These cells underwent expansion in response to injury and functioned in wound repair. They closely resembled vimentin-rich repair cell progenitors of mesodermal lineage within the lens epithelia that mediate injury repair, and whose ablation results in ineffective repair of the epithelium. Importantly, when these repair cells encounter a rigid extracellular matrix environment characteristic of injured tissues, they ca differentiate into fibrotic disease-causing myofibroblasts. Since diseases of the salivary glands result in structural defects, they are likely to trigger the repair process that involves activatio of these vinmentin-rich repair cells. In this proposal, we aim to characterize the SMG repair cells and to elucidate their role in SMG repair, including their ability to acquire myofibroblast phenotypes when the healing process is complete. Our hypothesis is that repair cell progenitors of mesodermal lineage in the SMG function as immediate responders to injury, that they mediate effective wound repair and that their fates include elimination by apoptosis and differentiation into myofibroblasts. We will test this hypothesis using genetic lineage tracing in transgenic mice that express a tamoxifen-inducible CreER under control of the endogenous vimentin promoter, coupled with ex vivo and in vivo SMG injury models. Two aims are proposed: 1) investigate the lineage of SMG repair cells, their response to injury, and the cell signaling and cytoskeletal functions essential to their reparative function; and 2) determine the fate of the repair cells following wound healing, including their ability to cause fibrotic disease Our proposed studies are significant and innovative because they will determine the identity of the SMG repair cells and explore whether these mesenchymal cells can potentially serve in salivary tissue regeneration. In addition, we will gain knowledge into how to manipulate these repair cells to prevent the development of salivary gland fibrotic disease. Our findings have the potential to be translated into effective therapeutic approaches for the regeneration of salivary gland structure and function, and to the fields of tissue injury repair and regeneration, in genera.