miRNAs regulate lung epithelial progenitor cells in development and injury repair

肺上皮祖细胞是发育和成人气道再生和修复所必需的。的 控制其行为的机制，包括发育过程中的增殖和分化， 气道损伤修复的进展在很大程度上是未知的。microRNAs（miRNAs）是基因表达的重要调节因子， 表达，但它们作为肺上皮祖细胞的调节剂的参与仍然知之甚少。 最近，我们已经证明miR-302/367是Gata 6-a转录因子必需的直接靶点， 正常的肺发育和气道再生-并调节肺上皮祖细胞的平衡 细胞增殖和分化以及细胞顶基极性。我们已经开始探索 miR-302/367介导的肺上皮祖细胞发育的重要性。miR-302/367的过表达 引起Sox 2+近端和Sox 9+远端祖细胞的扩增， 降低气道上皮细胞分化。值得注意的是，我们最近的研究表明，miR- 302/367在萘损伤的肺中与对照未损伤的肺相比显著增加，表明 miR-302/367在介导肺上皮基因转录和肺损伤反应中的潜在作用 气道修复和再生。因此，我的工作假设是，miR-302/367 作为Gata 6依赖性调控网络的组成部分，涉及多个积极和消极的 调节肺上皮祖细胞增殖和分化的反馈环。 更好的 了解miR-302/367如何调节气道上皮祖细胞的行为 上皮细胞对损伤反应的发育和再生将为研究多发性肺提供重要的见解 疾病 这将通过追求两个具体目标来实现： 具体目标1。K99阶段：确定miR-302/367在调节肺上皮细胞行为中的作用 祖细胞在气道上皮发育和损伤后再生中的作用。（a）确定下列因素的影响 使用ROSA-miR-302/367对肺上皮祖细胞发育的条件性获得和丧失 302/367和floxed miR-302/367小鼠系。B）确定Wnt 5a的表达降低是否与细胞凋亡相关。 负责miR-302/367功能获得突变体中肺上皮祖细胞的扩增。c）、 确定miR-302/367在气道上皮中的稳态和再生的需求。 具体目标2。R 00阶段：确定上皮祖细胞调节的潜在机制 miR-302/367在气道上皮发育和再生中的作用。 a）表征miR-302/367 在发育和损伤后气道再生过程中表达细胞。B）确定 在发育中的肺中由miR-302/367调节的直接靶点和下游信号通路。 c）确定 调节特定的miR-302/367调节靶点或途径是否会增强气道上皮细胞 修复和再生。

Lung epithelial progenitor cells are essential for development and adult airway regeneration and repair. The mechanisms controlling their behaviors including proliferation and differentiation during development and the progression of airway injury repair are largely unknown. MicroRNAs (miRNAs) are crucial modulators of gene expression, yet their involvement as regulators of lung epithelial progenitor cells is still poorly understood. Recently, We have demonstrated that miR-302/367 is a direct target of Gata6 -a transcription factor essential for proper lung development and airway regeneration- and regulates the balance of lung epithelial progenitor cell proliferation and differentiation as well as cell apical-basal polarity. We have begun to explore the importance of miR-302/367-mediated lung epithelial progenitor development. Overexpression of miR-302/367 in developing airway epithelium causes expansion of Sox2+ proximal and Sox9+ distal progenitor cells and decreased airway epithelial cell differentiation. Notably, our recent studies reveal that expression of miR- 302/367 is markedly increased in naphthalene-injured lungs compared to control uninjured lungs, suggesting a potential role for miR-302/367 in mediating lung epithelial gene transcription and the injury response during airway repair and regeneration. Therefore, my working hypothesis in this proposal is that miR-302/367 functions as components of a Gata6-dependent regulatory network involving multiple positive and negative feedback loops to modulate proliferation and differentiation of lung epithelial progenitor cells. A better understanding of how miR-302/367 regulates the behaviors of lung epithelial progenitor cells during airway epithelium development and regeneration in response to injury will provide important insights into multiple lung diseases. This will be accomplished by pursuing two specific aims: Specific Aim 1. K99 Phase: Determine the role of miR-302/367 in modulating the behaviors of lung epithelial progenitor cells during airway epithelium development and regeneration after injury. a) Determine the effects of conditional gain- and loss-of-miR-302/367 on lung epithelial progenitor cell development using ROSA-miR- 302/367 and floxed miR-302/367 mouse lines. b)Determine whether decreased expression of Wnt5a is responsible for the expansion of lung epithelial progenitors in miR-302/367 gain of function mutants. c) Determine the requirement of miR-302/367 for homeostasis and regeneration in airway epithelium. Specific Aim 2. R00 Phase: Determine the mechanisms underlying the regulation of epithelial progenitor cell behaviors by miR-302/367 in airway epithelium development and regeneration. a) Characterize miR-302/367 expressing cells in lung epithelium during development and airway regeneration after injury. b) Determine the direct targets and downstream signaling pathways regulated by miR-302/367 in developing lung. c) Determine whether modulation of specific miR-302/367-regulated targets or pathways would enhance airway epithelium repair and regeneration.