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Updated: Sep 25, 2026
Mouse Embryonic Lung Culture, A System to Evaluate the Molecular Mechanisms of Branching
Published on: June 30, 2010
Temporal effects of Sprouty on lung morphogenesis
Anne-Karina T Perl1, Isamu Hokuto, Maria-Antonietta Impagnatiello
1Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229-3039, USA.
Abstract:
Paracrine signaling mediated by FGF-10 and the FGF-R2IIIb receptor is required for formation of the lung. To determine the temporal requirements for FGF signaling during pulmonary morphogenesis, Sprouty-4 (Spry-4), an intracellular FGF receptor antagonist, was expressed in epithelial cells of the fetal lung under control of a doxycycline-inducible system. Severe defects in lobulation and severe lung hypoplasia were observed when Spry-4 was expressed throughout fetal lung development (E6.5-E18.5) or from E6.5 until E13.5. Effects of Spry-4 on branching were substantially reversed by removal of doxycycline from the dam at E12.5, but not at E13.5. In contrast, when initiated late in development (E12.5 to birth), Spry-4 caused less severe pulmonary hypoplasia. Expression of Spry-4 from E16.5 to E18.5 reduced lung growth and resulted in perinatal death due to respiratory failure. Expression of Spry-4 during the saccular and alveolar stages, from E18.5 to postnatal day 21, caused mild emphysema. These findings demonstrate that the embryonic-pseudoglandular stage is a critical time period during which Spry-sensitive pathways are required for branching morphogenesis, lobulation, and formation of the peripheral lung parenchyma.
Insights
Fibroblast growth factor (FGF) signaling is crucial for lung development. Inhibiting FGF signaling with Sprouty-4 (Spry-4) during early fetal stages severely impaired lung formation, highlighting the embryonic-pseudoglandular stage
Area of Science:
- Developmental biology
- Cell signaling
- Pulmonary medicine
Background:
- Fibroblast growth factor (FGF) signaling, specifically involving FGF-10 and FGF receptor 2 (FGF-R2IIIb), is essential for lung formation.
- Intracellular antagonists like Sprouty-4 (Spry-4) can modulate FGF receptor activity.
Purpose of the Study:
- To investigate the temporal requirements of FGF signaling during pulmonary morphogenesis.
- To understand the impact of inhibiting FGF signaling at different developmental stages on lung development.
Main Methods:
- A doxycycline-inducible system was used to express Sprouty-4 (Spry-4) in the epithelial cells of fetal lungs.
- Spry-4 expression was controlled across various embryonic and postnatal time points (E6.5-E18.5, E12.5-birth, E16.5-E18.5, E18.5-P21).
- Lung morphology, lobulation, branching, and overall growth were assessed.
Main Results:
- Early Spry-4 expression (E6.5-E13.5) led to severe lung hypoplasia and lobulation defects.
- Reversing Spry-4 expression at E12.5 partially rescued branching defects, but not when reversed at E13.5.
- Late Spry-4 expression (E16.5-E18.5) reduced lung growth, causing respiratory failure and perinatal death.
- Spry-4 expression during saccular/alveolar stages (E18.5-P21) resulted in mild emphysema.
Conclusions:
- The embryonic-pseudoglandular stage is a critical period for Spry-sensitive FGF pathways in branching morphogenesis, lobulation, and lung parenchyma formation.
- FGF signaling is required throughout lung development, with distinct sensitivities at different stages.
- Disruption of FGF signaling at later stages impacts lung growth and can lead to respiratory failure or emphysema.
