Glucocorticoid receptor antagonizes EGFR function to regulate eyelid development.

Area of Science:

• Developmental biology
• Molecular endocrinology
• Epithelial biology

Background:

• The glucocorticoid receptor (GR) is vital for epidermal morphogenesis.
• Eyelid development is a model for studying epithelial development, involving keratinocyte proliferation, apoptosis, and migration.
• GR function is critical for coordinated epithelial development.

Purpose of the Study:

• To investigate the role of GR in embryonic eyelid closure.
• To elucidate the molecular mechanisms underlying GR's function in epithelial development.
• To analyze the interplay between GR and epidermal growth factor receptor (EGFR) signaling during ontogeny.

Main Methods:

• Analysis of genetically modified mouse models with GR gain- and loss-of-function.
• Histological examination of GR(-/-) embryos during development.
• In vitro studies on epithelial cell migration and signaling pathways.

Main Results:

• GR deficiency leads to delayed and impaired eyelid closure in mouse embryos.
• GR(-/-) eyelid epithelial cells exhibit increased proliferation, apoptosis, and impaired differentiation.
• GR deficiency causes sustained MAPK/AP-1 pathway activation and KRT6 upregulation due to impaired GR/EGFR antagonism.

Conclusions:

• GR plays a critical role in regulating keratinocyte proliferation, apoptosis, differentiation, and migration during embryonic eyelid development.
• GR/EGFR antagonism is a key mechanism controlling ocular epithelial development.
• Dysregulation of GR signaling impacts epithelial development through altered EGFR signaling pathways.