Precise levels of nectin-3 are required for proper synapse formation in postnatal visual cortex

Area of Science:

• Neuroscience
• Developmental Biology
• Cell Biology

Background:

• Cortical neurons require specific proteins for synaptic connections.
• Nectin-3, a cell-adhesion molecule, is involved in synapse formation.
• Nectin-3 and nectin-1 are in mouse visual cortex upper-layer neurons, but their developmental role is unclear.

Purpose of the Study:

• To investigate the role of nectin-3 in the development of visual cortical circuits.
• To determine how nectin-3 levels affect dendritic spine density in developing neurons.

Main Methods:

• Nectin-3 expression was altered (knockdown or overexpression) in developing layer 2/3 visual cortical neurons using in utero electroporation.
• Dendritic spine densities were measured at three developmental time points: P14, P21, and P35.

Main Results:

• Nectin-3 knockdown increased dendritic spine densities at P21 and P35.
• Nectin-3 overexpression decreased dendritic spine densities.
• Effects were most pronounced on proximal secondary apical dendrites; nectin-3 lacking the afadin binding domain caused a greater decrease in spine density on basal dendrites.

Conclusions:

• Proper nectin-3 levels and function are essential for normal synapse formation.
• Nectin-3 influences synapse development on apical and basal dendrites in layer 2/3 visual cortex neurons.