Microglia and IL-6 drive the negative mood often associated with inflammation.

People who have certain neurological disorders, such as Alzheimer’s disease, Parkinson’s disease, or stroke, often exhibit low mood. Evidence suggests that inflammation plays a role in the pathogenesis of these neurological disorders and likely influences mood, as well. Findings from a 2021 study suggest that microglia activation drives the low mood often associated with neurological disorders.

Microglia are the brain’s resident immune cells. They serve an essential role in maintaining brain microenvironment homeostasis. Acute activation of microglia modulates inflammation and neurotoxicity, but chronic activation promotes brain inflammation and damage. Evidence suggests that microglia activation influences mood.

The investigators used chemogenetics, a research technique that uses drugs or other chemicals to modulate neural activity, to stimulate microglia activation in the brains of mice. They noted that levels of interleukin-6 (IL-6, a pro-inflammatory cytokine) and prostaglandins (hormone-like molecules that are involved in inflammation) increased in the animals' brains. In addition, the animals exhibited a low mood. Blocking microglia activity restored the animals' positive mood, however.

These findings suggest that microglia drive the low mood often associated with inflammation and that IL-6 is a prominent player in this process. Learn more about the role of inflammation and mood in this episode featuring Dr. Charles Raison.

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