EphrinB1/EphB3b Coordinate Bidirectional Epithelial-Mesenchymal Interactions Controlling Liver Morphogenesis and...

Area of Science:

• Developmental Biology
• Cell Signaling
• Organogenesis

Background:

• Organ positioning requires coordinated tissue movement, but underlying mechanisms are poorly understood.
• Eph/Ephrin signaling is crucial for cell-cell communication and tissue patterning.

Purpose of the Study:

• To elucidate the molecular mechanisms coordinating hepatic endoderm and lateral plate mesoderm (LPM) movement during zebrafish liver formation.
• To investigate the role of EphrinB1 and EphB3b in mediating cell-cell interactions and asymmetric organ positioning.

Main Methods:

• Zebrafish model system
• Analysis of EphrinB1 and EphB3b signaling pathways
• Cellular imaging and migration assays
• Investigating cell-cell interactions and tissue interfaces

Main Results:

• Bidirectional EphrinB1/EphB3b signaling coordinates hepatic endoderm and LPM movement for asymmetric liver positioning.
• EphrinB1 on hepatoblasts regulates migration and LPM interaction; EphB3b on LPM controls its polarity and movement.
• Eph/Ephrin signaling mediates hepatoblast motility via cellular protrusions and long-distance contacts.
• Intracellular EphrinB1 domains promote extension formation, while EphB3b interactions destabilize them.

Conclusions:

• Bidirectional signaling between epithelial (hepatoblasts) and mesenchyme-like (LPM) tissues is essential for liver bud formation and leftward asymmetry.
• Eph/Ephrin-mediated cell repulsion and attraction orchestrate complex tissue movements during organogenesis.