Long chain ceramides promote Anxiety-like behavior and microglia activation in female mice

Abstract

Background

Long-chain ceramides have been implicated in anxiety-like behavior and in priming microglial activation, suggesting a possible lipid–immune crosstalk in emotional regulation.

Methods

We systemically administered a mixture of C16:0, C18:0, C22:0, C24:0, and C24:1 ceramides to adult male and female mice. Anxiety-like behavior was assessed with behavioral tests. Microglial phenotypes in the cortex, hippocampus, and striatum were evaluated via flow cytometry. Regression models examined associations between behavior and immune markers. In vitro assays assessed phagocytosis, gene expression, mitochondrial potential, and ROS production in microglia after ceramide exposure.

Results

Female, but not male, mice showed anxiety-like behavior after ceramide treatment. CD86+ microglia increased in the cortex, while CD206+ microglia decreased across brain regions. Behavioral scores correlated with CD86+ cells in cortex and CD206+ cells in hippocampus. In vitro, ceramides enhanced phagocytosis and induced NLRP3 and TNF-α expression. Ceramides also reduced mitochondrial potential and increased ROS in microglia.

Conclusions

Ceramide administration was associated with anxiety-like behavior in female mice, along with changes in microglial activation. These effects appear to be associated with mitochondrial dysfunction and oxidative stress, suggesting a lipid–immune interaction that could contribute to anxiety vulnerability.