Partners in plasticity: serotonergic glial interactions in brain circuit remodeling

Area of Science:

• Neuroscience
• Cell Biology
• Developmental Biology

Background:

• Brain circuit development relies on experience-dependent synapse remodeling.
• Serotonin (5-HT) is a key neuromodulator of neural plasticity.
• Emerging evidence highlights critical roles for glia in 5-HT signaling and synaptic remodeling.

Purpose of the Study:

• To review recent findings on serotonin's role in both neuronal and glial functions related to experience-dependent brain circuit remodeling.
• To discuss the implications of glial 5-HT signaling in neurodevelopmental disorders and potential therapeutic strategies.

Main Methods:

• Review of recent studies in *Drosophila* and foundational mammalian research.
• Focus on glial 5-HT biosynthesis, receptor activation, and matrix metalloprotease activity.
• Analysis of experience-dependent extracellular matrix remodeling, glial infiltration, and synapse elimination.

Main Results:

• Serotonin (5-HT) modulates synaptic plasticity through both neurons and glia.
• Glial 5-HT signaling, including 5-HT_2A receptor activation, is crucial for experience-driven synapse elimination.
• Targeted glial 5-HT induction can reopen critical period-like synapse pruning in mature brains.

Conclusions:

• Glia act as serotonergic mediators of synaptic remodeling, influencing brain circuit connectivity.
• Glia-to-glia 5-HT signaling may be a conserved mechanism gating circuit plasticity.
• Harnessing glial 5-HT signaling offers targeted therapeutic potential for neurological disorders and cognitive dysfunction.