Mechanisms of submucosal gland cell mediated airway regeneration

摘要 大多数呼吸道疾病被认为是由异常或缺乏有效的修复机制引起的。 受伤。确定细胞来源和促进内源性再生的机制 而这可以帮助基于细胞的疗法是非常必要的。在我们最近出版的著作中，我们发现了一种新的储备 呼吸道组织中的多潜能干细胞群体。我们发现驻留在细胞内的肌上皮细胞 呼吸道的粘膜下腺(SMG)通常是非常静止的，但它们会广泛增殖和迁移 在严重损伤后重新填充表面呼吸道上皮(SAE)。我们进一步鉴定了SOX9介导的 转录程序是SMG来源的肌上皮细胞增殖和迁移所必需的 我也是。此外，我们发现部分SMG来源的细胞具有完全转化为SAE的能力，尽管 非常慢。我们目前的初步数据表明，SMG来源的细胞中没有转化为 SAE细胞继续保持SMG细胞特性，包括转录因子SOX9的表达， 对于延长的时间段。此外，使用新开发的小鼠模型和体内成像研究我们的 初步数据表明，SMG-腺泡腔细胞(浆液细胞和粘液细胞)也具有迁移能力。 致SAE。根据我们的初步数据，我们假设SMG-腺泡腔细胞具有 迁移并有助于SAE的再生，这一过程依赖于MEC的迁移。我们 也假设SOX9依赖的机制必须被下调以完成 SMG来源的细胞转化为SAE细胞。 这项建议的主要目标是解决SMG-腺泡腔细胞的潜在贡献 以促进表面上皮细胞的正常再生。在Aim1，我们将定性和定量地 确定SMG-腺泡细胞在SAE损伤后修复中的作用。我们将用我们新开发的 结合多光子辅助活体成像的体内谱系追踪小鼠模型 SMG-腺泡细胞迁移能力及其在SAE修复中的作用。我们还将使用白喉毒素 介导性消融微血管内皮细胞以验证我们的假设：SMG-腺泡腔细胞的增殖和迁移 依赖微血管内皮细胞。在AIM2中，我们将测试我们的假设，即SOX9的损失足以完成 在急性损伤和慢性炎症的背景下，SMG来源的细胞转化为SAE细胞。这部作品 具有额外的重要性，因为我们发现SMG来源的细胞对SAE再生的贡献发生在 多种形式的伤害背景，包括流感病毒、二氧化硫、氯和慢性过敏原- 诱导的呼吸道损伤。因此，拟议研究的结果将对 由于再生缺陷而发生的呼吸道疾病。这项工作将为以后的研究奠定基础 涉及人类呼吸道再生。

SUMMARY Most respiratory diseases are thought to result from an aberrant or a lack of efficient repair mechanisms following injuries. Identifying the cellular sources and the mechanisms that can enhance the endogenous regeneration and that can aid cell-based therapies is much needed. In our recent published work, we identified a novel reserve multipotent stem cell population in the airway tissues. We found that myoepithelial cells that reside in the submucosal glands (SMG) of the airways are normally very quiescent but they proliferate extensively and migrate to repopulate surface airway epithelium (SAE) following severe damage. We further identified SOX9-mediated transcriptional programs are necessary for the proliferation and migration of SMG-derived myoepithelial cells to SAE. Furthermore, we found that a fraction of SMG-derived cells have the ability to fully convert into SAE, albeit very slowly. Our current preliminary data indicated that the fraction of SMG-derived cells that do not convert into SAE cells continue to maintain SMG cell characteristics, including the expression of transcription factor SOX9, for extended time periods. In addition, using newly developed mouse models and intra-vital imaging studies our preliminary data indicate that SMG-acinar luminal cells (serous and mucous cells) also have the ability to migrate to SAE. Based on our preliminary data, we hypothesize that SMG-acinar luminal cells have the ability to migrate and contribute to SAE regeneration and that this process is dependent on MECs migration. We also hypothesize that SOX9-dependent mechanisms must be downregulated for the complete conversion of SMG-derived cells into SAE cells. The major objectives of this proposal are to address both the potential contribution of SMG- acinar luminal cells to surface epithelium and to enhance proper regeneration. In Aim1, we will qualitatively and quantitatively determine the contribution of SMG-acinar luminal cells to SAE repair after injury. We will use our newly developed in vivo lineage tracing mouse models coupled with multi-photon assisted intravital imaging to determine the ability of SMG-acinar luminal cells migration and contribution to SAE repair. We will also use diphtheria toxin mediated ablation of MECs to test our hypothesis that SMG-acinar luminal cell proliferation and migration is dependent on MECs. In Aim2, we will test our hypothesis that loss of SOX9 is sufficient for the complete conversion of SMG-derived cells into SAE cells in the context of acute injury and chronic inflammation. This work has taken on added importance, as we found that SMG-derived cells contribution to SAE regeneration occurs in multiple forms of injury contexts including, influenza virus, Sulphur dioxide, chlorine, and chronic allergen- induced airway damage. Therefore, the outcomes from the proposed studies will have broader significance to airway diseases that occur due to defective regeneration. This work will lay the foundation for future studies involving human airway regeneration.