TREM2 Links Early-Life Deprivation to Synaptic and Cognitive Recovery
Publication Title: The microglial TREM2 receptor programs hippocampal development in a mouse model of childhood deprivation
Summary
- Question
- This study investigated how early-life deprivation affects microglia, a type of immune cell in the brain, and its impact on hippocampal development and cognitive function. The researchers examined the role of the TREM2 receptor, which is crucial for microglia's ability to prune unnecessary synapses during brain development, and whether early enrichment could mitigate these effects.
- Why it Matters
- Early-life adversity, such as neglect, is linked to long-term cognitive and emotional deficits. Understanding the biological mechanisms behind these effects is essential for developing targeted interventions. Microglia play a key role in brain development, and disruptions to their function may contribute to impaired memory and learning. This study highlights the importance of microglial TREM2 in shaping hippocampal function, offering potential strategies for improving outcomes in individuals exposed to childhood neglect.
- Methods
- The researchers used a mouse model of deprivation called limited bedding (LB), which mimics the effects of neglect by providing insufficient nesting material. They studied microglial activity, synaptic pruning, and hippocampal function in both normal and genetically modified mice lacking or overexpressing TREM2. Additionally, they tested the effects of introducing enrichment, such as toys, during critical developmental periods.
- Key Findings
- LB reduced TREM2 expression in microglia, impairing their ability to prune synapses during a critical developmental window. Overexpressing TREM2 restored normal pruning and rescued deficits in hippocampal connectivity and fear learning. Enrichment during postnatal development normalized synaptic pruning in a TREM2-dependent manner, improving contextual memory in adolescent male mice.
- Implications
- These findings suggest that TREM2 plays a central role in mediating the effects of deprivation and enrichment on brain development. Enhancing microglial TREM2 activity could represent a therapeutic approach to mitigate cognitive deficits caused by early-life adversity. The study also underscores the importance of providing targeted interventions during sensitive developmental periods.
- Next Steps
- The authors suggest further research to explore whether enrichment can enhance synaptic maturity and connectivity beyond the hippocampus. Additionally, they recommend investigating other molecular pathways that contribute to microglial function and their potential as therapeutic targets for addressing the effects of early-life deprivation.
- Funding Information
- This research was supported by the National Institute of Mental Health (awards R01MH136490 and R01MH130825), the Clinical Neuroscience Division of the VA National Center for PTSD, and the National Institute on Aging (award R01AG056114). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Full Citation
Ahmed S, Bowers C, Munoz-Martin J, Jamwal S, Sanganahalli B, Chen K, Giuliano L, Kaswan Z, Hyder F, Yang X, Kaffman A. The microglial TREM2 receptor programs hippocampal development in a mouse model of childhood deprivation. Brain Behavior And Immunity 2026, 136: 106555. PMID: 41887542, PMCID: PMC13049556, DOI: 10.1016/j.bbi.2026.106555.
This AI-assisted summary has been reviewed and approved by at least one of the study's authors to ensure it accurately reflects the research.
Authors
Sahabuddin Ahmed
First AuthorArie Kaffman, MD, PhD
Last AuthorAssociate Professor of Psychiatry