Wellcome Trust/CRUK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK.
Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK.
Development. 2023 Jun 1;150(11). doi: 10.1242/dev.201284.
Multipotent epithelial progenitor cells can be expanded from human embryonic lungs as organoids and maintained in a self-renewing state using a defined medium. The organoid cells are columnar, resembling the cell morphology of the developing lung tip epithelium in vivo. Cell shape dynamics and fate are tightly coordinated during development. We therefore used the organoid system to identify signalling pathways that maintain the columnar shape of human lung tip progenitors. We found that EGF, FGF7 and FGF10 have distinct functions in lung tip progenitors. FGF7 activates MAPK/ERK and PI3K/AKT signalling, and is sufficient to promote columnar cell shape in primary tip progenitors. Inhibitor experiments show that MAPK/ERK and PI3K/AKT signalling are key downstream pathways, regulating cell proliferation, columnar cell shape and cell junctions. We identified integrin signalling as a key pathway downstream of MAPK/ERK in the tip progenitors; disrupting integrin alters polarity, cell adhesion and tight junction assembly. By contrast, stimulation with FGF10 or EGF alone is not sufficient to maintain organoid columnar cell shape. This study employs organoids to provide insight into the cellular mechanisms regulating human lung development.
多能上皮祖细胞可从人胚肺中扩增为类器官，并使用定义的培养基在自我更新状态下维持。类器官细胞呈柱状，类似于体内发育中的肺尖端上皮细胞的形态。细胞形态动力学和命运在发育过程中紧密协调。因此，我们使用类器官系统来鉴定维持人肺尖端祖细胞柱状形态的信号通路。我们发现 EGF、FGF7 和 FGF10 在肺尖端祖细胞中有不同的功能。FGF7 激活 MAPK/ERK 和 PI3K/AKT 信号通路，足以促进原代尖端祖细胞的柱状细胞形态。抑制剂实验表明，MAPK/ERK 和 PI3K/AKT 信号通路是调节细胞增殖、柱状细胞形态和细胞连接的关键下游途径。我们确定整合素信号通路是尖端祖细胞中 MAPK/ERK 的关键下游途径；破坏整合素会改变极性、细胞黏附和紧密连接组装。相比之下，单独用 FGF10 或 EGF 刺激不足以维持类器官的柱状细胞形态。本研究采用类器官深入了解调节人肺发育的细胞机制。
