Intercellular communication and cell regulation in airway epithelial ensembles in regeneration and disease

项目总结： 在已发表的工作中，我们使用白喉毒素诱导的遗传细胞消融来了解 在失去一种单一的呼吸道上皮细胞类型后，正常的组织结构被恢复。我们 发现了4个以前没有描述过的新现象(1)一个完全成熟的脊椎动物细胞 当干细胞被消融时，可以去分化为干细胞，(2)认为消融的最多 呼吸道上皮中终末分化的细胞类型不会产生再生 反应表明纤毛细胞没有发出反馈损伤信号 引导以干细胞为基础的再生，(3)基底细胞不仅是新细胞的来源，而且 它们向分泌上皮细胞发送前馈信号，以主动协调整个 组织行为，最后(4)基底细胞不是干细胞的同质群体 细胞。我们进一步确定Notch信号是这两种新型干细胞的机制基础 前馈信号机制，并作为基础细胞异质性的基础。 在这项应用中，我们建议继续使用精确的遗传细胞消融研究来 询问呼吸道上皮的调节电路，并定义Notch信号如何 协调特定数量的呼吸道上皮细胞的行为。我们现在建议 直接扩展我们先前检查稳态呼吸道上皮的工作，并部署我们的 研究生理相关损伤的模型系统。我们有三个普遍的假设 我们打算使用我们现在开发的用于细胞消融和细胞的工具来验证或驳斥 特定类型的Notch信令调制。首先，我们假设基础干细胞是一种 在再生反应中扮演中心角色，并积极利用Notch配体 从根本上调控多种细胞类型的粘液化生过程。因此，与其说是 除了简单地提供新的细胞来取代受伤的细胞之外，干细胞被假设为 协调整个组织的行为。其次，我们假设两者的不同组成部分 Notch信号的发送(Notch配体)和接收(Notch Receptor)通路是 对不同程度和类型的伤害有不同的反应。第三，我们假设 必须存在调节再生的反馈信号以补充新的饲料 我们最近演示的转发信号机制。此外，由于这一点 纤毛细胞似乎没有信号，我们假设反馈信号一定是发出的 来自分泌细胞。这项工作具有额外的重要性，作为抗体试剂 切迹调制现在被认为是临床干预措施。

Project Summary: In published work, we used diphtheria toxin-induced genetic cellular ablation to understand how normal tissue architecture is restored after the loss of a single airway epithelial cell type. We discovered 4 new phenomenon not previously described (1) that a fully mature vertebrate cell can dedifferentiate into a stem cell when stem cells are ablated, (2) that the ablation of the most terminally differentiated cell type in the airway epithelium does not engender a regenerative response suggesting that there is no feedback injury signal emanating from the ciliated cell to guide stem cell-based regeneration, (3) that basal cells are not merely sources of new cells, but that they send feed-forward signals to secretory epithelial cells to actively orchestrate whole tissue behavior, and finally (4) that the basal cells are not a homogeneous population of stem cells. We further identified Notch signaling as the mechanistic basis for both the novel stem cell feed-forward signaling mechanism and as the basis of basal cell heterogeneity. In this application, we propose to continue our use of precise genetic cellular ablation studies to interrogate the regulatory circuitry of the airway epithelium, and to define how Notch signaling orchestrates the behavior of specific populations of airway epithelial cells. We now propose to directly extend our prior work examining the steady state airway epithelium, and deploy our model systems to study physiologically relevant- injury. We have three general hypotheses that we intend to verify or refute using our now well-developed tools for cellular ablation and cell type-specific Notch signaling modulation. First, we hypothesize that the basal stem cell is a central actor during the regenerative response, and that it actively makes use of Notch ligands to fundamentally regulate the process of mucous metaplasia in multiple cell types. Thus, rather than simply serving to supply new cells to replace injured ones, stem cells are hypothesized to orchestrate whole tissue behaviors. Secondly, we hypothesize that distinct components of both the Notch signal sending (Notch ligands) and receiving (Notch receptors) pathways are modulated differentially in response to differing degrees and types of injury. Thirdly we postulate that a feedback signal regulating regeneration must be present to complement the novel feed forward signaling mechanism that we have recently demonstrated. Furthermore, since this signal seems absent from ciliated cells, we hypothesize that the feedback signal must emanate from the secretory cells. This work has taken on added importance, as antibody reagents for Notch modulation are now being considered as clinical interventions.