PDF(Pubmed)
Abstract：
Congenital lung malformations are fatal at birth in their severe forms. Prevention and early intervention of these birth defects require a comprehensive understanding of the molecular mechanisms of lung development. We find that the loss of inturned (Intu), a cilia and planar polarity effector gene, severely disrupts growth and branching morphogenesis of the mouse embryonic lungs. Consistent with our previous results indicating an important role for Intu in ciliogenesis and hedgehog (Hh) signaling, we find greatly reduced number of primary cilia in both the epithelial and mesenchymal tissues of the lungs. We also find significantly reduced expression of Gli1 and Ptch1, direct targets of Hh signaling, suggesting disruption of cilia-dependent Hh signaling in Intu mutant lungs. An agonist of the Hh pathway activator, smoothened, increases Hh target gene expression and tubulogenesis in explanted wild type, but not Intu mutant, lungs, suggesting impaired Hh signaling response underlying lung morphogenetic defects in Intu mutants. Furthermore, removing both Gli2 and Intu completely abolishes branching morphogenesis of the lung, strongly supporting a mechanism by which Intu regulates lung growth and patterning through cilia-dependent Hh signaling. Moreover, a transcriptomics analysis identifies around 200 differentially expressed genes (DEGs) in Intu mutant lungs, including known Hh target genes Gli1, Ptch1/2 and Hhip. Genes involved in muscle differentiation and function are highly enriched among the DEGs, consistent with an important role of Hh signaling in airway smooth muscle differentiation. In addition, we find that the difference in gene expression between the left and right lungs diminishes in Intu mutants, suggesting an important role of Intu in asymmetrical growth and patterning of the mouse lungs.
摘要：
先天性肺畸形在出生时的严重形式是致命的。预防和早期干预这些出生缺陷需要全面了解肺发育的分子机制。我们发现，inturn(Intu)的损失，纤毛和平面极性效应基因，严重破坏小鼠胚胎肺的生长和分支形态发生。与我们之前的结果表明Intu在纤毛发生和刺猬（Hh）信号传导中的重要作用一致，我们发现肺上皮和间充质组织中的原发性纤毛数量大大减少。我们还发现Gli1和Ptch1的表达显着降低，Hh信号的直接靶标，提示Intu突变肺中纤毛依赖性Hh信号的破坏。Hh通路激活剂的激动剂，平滑，在外植野生型中增加Hh靶基因表达和肾小管发生，但不是Intu突变体,肺,提示Intu突变体肺形态发生缺陷潜在的Hh信号应答受损。此外，去除Gli2和Intu完全消除了肺的分支形态发生，强烈支持Intu通过纤毛依赖性Hh信号传导调节肺生长和模式的机制。此外，转录组学分析在Intu突变肺中鉴定出大约200个差异表达基因(DEGs)，包括已知的Hh靶基因Gli1、Ptch1/2和Hip。参与肌肉分化和功能的基因在DEGs中高度富集，符合Hh信号在气道平滑肌分化中的重要作用。此外,我们发现，在Intu突变体中，左肺和右肺之间的基因表达差异减小，表明Intu在小鼠肺的不对称生长和模式中的重要作用。
