AP-2alpha knockout mice exhibit optic cup patterning defects and failure of optic stalk morphogenesis

Area of Science:

• Developmental Biology
• Ophthalmology
• Genetics

Background:

• Proper development of the retina and optic nerve relies on coordinated patterning and morphogenesis of the optic neuroepithelium.
• Transcription factor activating protein-2 alpha (AP-2alpha) has a known non-cell autonomous role in optic cup development.
• The precise mechanisms underlying optic cup abnormalities in AP-2alpha knockout (KO) mice were not fully understood.

Purpose of the Study:

• To elucidate the morphological and molecular basis of optic cup abnormalities in AP-2alpha KO mice.
• To investigate the role of AP-2alpha in ocular development and tissue interactions.

Main Methods:

• Analysis of AP-2alpha knockout (KO) mouse models.
• Morphological assessment of ocular development at the optic vesicle and optic cup stages.
• Molecular analysis of signaling pathways, including sonic hedgehog.

Main Results:

• Patterning and morphogenetic defects in AP-2alpha KO mice initiate at the optic vesicle stage.
• Ectopic neural retina and optic stalk-like tissue replaced retinal pigment epithelium during optic cup formation.
• AP-2alpha KO eyes exhibited coloboma, optic stalk defects, and expanded PAX2-positive tissue, linked to increased sonic hedgehog signaling.

Conclusions:

• Loss of AP-2alpha disrupts crucial tissue-tissue interactions essential for ocular development.
• AP-2alpha KO mice present a valuable model for studying human ocular diseases linked to TFAP2A mutations.
• The findings underscore the critical role of AP-2alpha in coordinating craniofacial and ocular development.