Alkylindole-sensitive receptors modulate microglial cell migration and proliferation

Area of Science:

• Neuroscience
• Immunology
• Pharmacology

Background:

• Microglia, the immune cells of the central nervous system, express G protein-coupled receptors (GPCRs) that modulate their activation.
• Cannabinoids like THC and synthetic compounds such as WIN55212-2 (WIN-2) target CB1 and CB2 receptors, but WIN-2 also activates an unknown receptor on microglia.
• Lack of selective pharmacological tools hindered the study of these unknown alkylindole (AI)-sensitive receptors in microglial activation.

Purpose of the Study:

• To investigate the presence and function of AI-sensitive receptors in primary mouse microglia.
• To determine the role of these receptors in microglial proliferation, migration, and M1/M2 polarization.

Main Methods:

• Utilized newly developed AI analogues to probe AI-sensitive receptors in primary mouse microglia.
• Assessed receptor functionality via radioligand binding and intracellular cAMP level measurements.
• Evaluated effects on cell proliferation, migration, and response to M1/M2 cytokines.

Main Results:

• Mouse microglia express functional AI-sensitive receptors that regulate basal and ATP-stimulated migration.
• AI analogues inhibit macrophage-colony stimulating factor (M-CSF)-stimulated proliferation but not basal proliferation.
• AI analogues did not affect M1 or M2 effector protein expression, though cytokine activation modulated microglial response to AI analogues.

Conclusions:

• Microglia express functional AI-sensitive receptors that selectively control migration and proliferation.
• These AI-sensitive receptors represent novel therapeutic targets for modulating microglial activation processes.