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Sex Differences in Mouse Hippocampal Astrocytes after In-Vitro Ischemia
Published on: October 25, 2016
Sex differences in somatosensory circuitry are programmed by developmental microglia-astrocyte interaction
Abigayle Duffy1, Leigh Ellen Fremuth2, Madison Doceti2
1Brain Immunology and Glia Center, University of Virginia, Charlottesville, VA 22903, USA; Department of Neuroscience, University of Virginia, Charlottesville, VA 22903, USA; Neuroscience Graduate Program, University of Virginia, Charlottesville, VA 22903, USA.
Cell Reports
|July 25, 2026
Summary
Male mice have more brain synapses than females due to microglia differences. This sex difference in synapse density in the somatosensory cortex (S1) impacts neuronal activity.
Area of Science:
- Neuroscience
- Developmental Biology
- Cell Biology
Background:
- Cortical synapse density differs between sexes, but mechanisms remain unclear.
- Understanding sex differences in the brain is crucial for neuroscience.
- Previous research has not fully elucidated the developmental origins of synapse density disparities.
Purpose of the Study:
- To investigate the mechanism behind greater excitatory synapse density in the male mouse somatosensory cortex (S1).
- To identify the role of microglia and astrocytes in developmental synapse formation.
- To explore the functional significance of sex differences in S1 synapse density.
Main Methods:
- Comparative analysis of synapse density in male and female mouse S1.
- Investigation of microglial phagocytic activity and astrocyte engulfment during development.
- Assessment of MERTK-dependent pathways and estrogen signaling.
- Measurement of astrocyte-derived synaptogenic factors (hevin, thrombospondin-2).
- Electrophysiological recordings to assess neuronal activity.
Main Results:
- Male mice exhibit higher excitatory synapse density in S1, emerging during development and persisting into adulthood.
- Increased microglial phagocytosis in females leads to greater astrocyte engulfment via MERTK signaling, modulated by estrogen.
- Higher astrocyte density in males correlates with increased hevin and thrombospondin-2.
- Sex differences in S1 synapse density correlate with altered neuronal activity in males.
Conclusions:
- Microglial-mediated astrocyte engulfment during a critical developmental window contributes to sex differences in S1 synapse density.
- Estrogen signaling and MERTK pathway play key roles in regulating these developmental processes.
- The observed sex difference in synapse density is functionally linked to neuronal activity levels in the male S1.
