Magnolol Ameliorates Depression Through Modulating the TREM2-DOK3-ERK Pathway

Area of Science:

• Neuroscience
• Pharmacology
• Immunology

Background:

• Depression is a prevalent mental disorder characterized by high recurrence rates and often associated with neuroinflammation.
• Magnolol (MA), a compound from Magnolia officinalis, exhibits antidepressant properties.
• Understanding the molecular mechanisms underlying MA's effects is crucial for developing effective depression therapies.

Purpose of the Study:

• To investigate the molecular mechanisms behind the antidepressant effects of Magnolol (MA) in a mouse model of depression and in BV2 microglia.
• To elucidate MA's impact on neuroinflammation, microglial activation, and related signaling pathways.

Main Methods:

• Behavioral tests (Sucrose Preference Test, Forced Swim Test, Open Field Test) were used to assess depression-like behaviors in mice.
• Levels of proinflammatory cytokines (IL-6, TNF-α, IL-1β), BDNF, and IL-10 were measured.
• Microglial morphology, iNOS expression, TREM2, p-DOK3/DOK3, and p-ERK/ERK ratios were analyzed in BV2 microglia.
• TREM2 knockdown was performed to validate its role in MA's effects.

Main Results:

• MA significantly reduced depression-like behaviors and suppressed neuroinflammation by decreasing IL-6, TNF-α, and IL-1β levels.
• MA increased neuroprotective factors (BDNF, IL-10) and inhibited microglial activation.
• MA's mechanism involves upregulating TREM2 and DOK3 phosphorylation while downregulating ERK phosphorylation, effects abrogated by TREM2 knockdown.

Conclusions:

• Magnolol (MA) demonstrates antidepressant effects by mitigating depression-like behaviors and neuroinflammation in mice.
• MA exerts its protective effects through the TREM2/DOK3 pathway, inhibiting ERK phosphorylation and subsequent microglial activation.
• These findings suggest MA as a potential therapeutic agent for depression, targeting neuroinflammatory pathways.