Precise alternating cellular pattern in the inner ear by coordinated hopping intercalations and delaminations

Area of Science:

• Developmental biology
• Cell biology
• Mechanobiology

Background:

• The organ of Corti in the mammalian inner ear exhibits highly organized alternating sensory hair cells (HCs) and supporting cells.
• The developmental mechanisms generating this precise cellular arrangement, particularly the single row of inner hair cells (IHCs), remain unclear.

Purpose of the Study:

• To elucidate the cellular and mechanical processes driving the formation of the single IHC row in the developing mammalian inner ear.

Main Methods:

• Live imaging of mouse inner ear explants.
• Hybrid computational modeling integrating mechanical and regulatory factors.

Main Results:

• Identified a novel "hopping intercalation" process where IHC precursor cells move beneath the apical plane.
• Observed delamination of cells with low Atoh1 expression that were not in the correct row.
• Demonstrated that differential cell adhesion contributes to the straightening and organization of the IHC row.

Conclusions:

• Precise IHC row formation is achieved through a coordinated mechanism involving cell intercalation, selective delamination, and differential adhesion.
• This developmental patterning relies on the interplay of signaling pathways and mechanical forces, applicable to other developmental contexts.