Metabolic reprogramming is critical to microglial activation in Huntington's disease

Area of Science:

• Neuroscience
• Immunology
• Pharmacology

Background:

• Huntington's disease (HD) is a fatal neurodegenerative disorder linked to expanded CAG repeats in the Huntingtin gene.
• Neuroinflammation, characterized by microglial activation and pro-inflammatory cytokines, is a hallmark of HD brains.
• The precise mechanisms governing neuroinflammation and microglial responses in HD remain unclear.

Purpose of the Study:

• To investigate the neuroprotective effects of metformin in a mouse model of Huntington's disease.
• To elucidate the mechanisms by which metformin modulates neuroinflammation and microglial activation in HD.

Main Methods:

• Utilized a transgenic mouse model of Huntington's disease.
• Administered metformin and assessed neuroinflammation markers, microglial activation states, and immunometabolism.
• Analyzed mitochondrial dynamics and cellular metabolism in brain tissue and primary microglia.

Main Results:

• Metformin significantly inhibited mitochondrial DNA release and subsequent neuroinflammation in the HD mouse brain.
• Metformin reduced pro-inflammatory cytokines and pathological microglial clustering, promoting a homeostatic microglial phenotype.
• The drug improved aberrant immunometabolism in HD microglia and reprogrammed deregulated cellular metabolism.

Conclusions:

• Metformin exerts neuroprotective effects in Huntington's disease by controlling microglial activation and neuroinflammation.
• The drug's mechanism involves regulating mitochondrial fission, restoring metabolic balance in microglia, and reducing inflammatory responses.
• Metformin demonstrates potential as a therapeutic agent for mitigating neuroinflammation in Huntington's disease.