Microglia regulate neuronal and behavioural functions under physiological and pathological conditions

Area of Science:

• Neuroscience
• Immunology
• Cell Biology

Background:

• Microglia are central nervous system immune cells involved in synaptic pruning during development.
• Recent advancements in in vivo imaging and genetic manipulation tools have enhanced the study of microglia and neuron interactions.
• These tools are uncovering novel functions of microglia beyond their traditional roles.

Purpose of the Study:

• To explore the multifaceted roles of microglia in neuronal regulation and behavior.
• To elucidate the molecular mechanisms underlying neuron-microglia communication.
• To investigate the impact of stress on microglial activation and subsequent behavioral changes.

Main Methods:

• In vivo imaging techniques.
• Genetic manipulation of microglia and neurons.
• Analysis of receptor signaling pathways (e.g., P2Y12, adenosine A1, PGE receptor 1).
• Assessment of behavioral responses to stimuli like lipopolysaccharide and chronic stress.
• Measurement of pro-inflammatory cytokine release.

Main Results:

• Microglia regulate neuronal activity via adenosine triphosphate-P2Y12 and adenosine-adenosine A1 receptor signaling in the striatum.
• Microglia-derived prostaglandin E2 (PGE2) signaling mediates lipopolysaccharide-induced aversion.
• Chronic stress activates microglia through toll-like receptor (TLR) 2 and TLR4 in the medial prefrontal cortex, leading to social avoidance.
• Microglia release pro-inflammatory cytokines that suppress neuronal activity.

Conclusions:

• Microglia play critical roles in synaptic regulation, neuronal activity modulation, and behavioral responses.
• Specific signaling pathways mediate neuron-microglia interactions influencing both physiological and pathological states.
• Microglial activation by stress contributes to behavioral changes, highlighting their involvement in psychological stress responses.