WNT7A-positive dendritic cytonemes control synaptogenesis in cortical neurons

Area of Science:

• Neuroscience
• Cell Biology
• Developmental Biology

Background:

• Synaptogenesis refines neuronal connections through filopodial contacts.
• Wnt/β-catenin and calcium signaling are implicated in synapse formation.
• The spatial organization of synapses along dendrites remains poorly understood.

Purpose of the Study:

• To investigate the role of WNT7A in orchestrating synapse formation and spatial arrangement.
• To elucidate the mechanism by which WNT7A guides synaptogenesis on dendritic filopodia.

Main Methods:

• Studied human cortical neurons during spine formation.
• Utilized immunofluorescence to track WNT7A, LRP6, and synaptic proteins.
• Induction of calcium transients was monitored.

Main Results:

• WNT7A localizes to dendritic filopodia tips during spine formation.
• Filopodial WNT7A triggers localized LRP6, calcium transients, and synaptic protein clustering.
• Soluble WNT7A lacks spatial guidance, leading to ectopic synapse formation.

Conclusions:

• Dendritic filopodia act as WNT7A-bearing cytonemes for targeted synaptogenesis.
• WNT7A-mediated focal calcium signaling dictates precise synapse positioning.
• This mechanism provides spatial control critical for neuronal circuit development.