Keratinocyte growth factor and embryonic rat lung morphogenesis

Area of Science:

• Developmental Biology
• Cell Biology
• Pulmonology

Background:

• Lung morphogenesis is a complex process involving intricate signaling pathways.
• Keratinocyte growth factor (KGF) and hepatocyte growth factor (HGF) are implicated in epithelial development.

Purpose of the Study:

• To investigate the roles of KGF and HGF in fetal lung development and morphogenesis.
• To elucidate the specific effects of KGF on lung branching and epithelial differentiation.

Main Methods:

• Polymerase chain reaction (PCR) to detect growth factor transcripts.
• In vitro culture of fetal rat lung explants with varying concentrations of KGF and antibodies.
• Electron microscopy, Northern blot analysis, and in situ hybridization to assess cellular changes and gene expression.

Main Results:

• KGF transcripts and receptors were detected early in lung development and increased during morphogenesis.
• Exogenous KGF reduced branching and induced cyst-like structures containing type II alveolar epithelial cells.
• KGF treatment increased surfactant protein C (SP-C) mRNA expression and altered distal epithelial cell patterning.
• Acidic fibroblast growth factor mimicked KGF effects, while TGF-beta(1) inhibited branching.
• HGF had no significant impact on lung branching or growth.

Conclusions:

• KGF plays a critical role in regulating fetal lung branching, epithelial growth, differentiation, and spatial patterning.
• HGF does not appear to be a major regulator of lung morphogenesis.
• KGF signaling is a key determinant of normal lung development.