Neuron: Early inflammation can lead to the imbalance of the phagocytic ability of microglia, which increases the risk of depression

Inflammation early in life, such as trauma and viral infection , can greatly increase the risk of depression in adulthood
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However, the mechanism is unclear

Inflammation early in life, such as trauma and viral infection , can greatly increase the risk of depression in adulthood

2021 Nian 7 Yue 6 Ri , a study published in Neuron Neuron on by the Chinese Academy of Sciences (CAS) team and the Chinese Academy of Sciences Professor Xu Lin cooperation Life Science and Medicine Department Professor Zhang led the study revealed inflammation early in life can induce adolescent depressive symptoms of Mechanism

Studies have found that inflammation in early life can cause the microglia in the anterior cingulate cortex (ACC) of the brain to become more sensitive to random stress events during puberty development, and then microglia will overwhelm the dendritic spines of neurons.
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This impairs the ability of ACC glutamatergic neurons (ACCGlu) to fight stress, which induces depression in adolescents .

Microglia are the resident immune cells of the brain , which transform into a reactive state in response to stress challenges
.

In a pathological state, activated microglia are the commander of the inflammatory state of the brain tissue.

Microglia are the brain's resident immune cells, it will be in response to immune pressure pressure into a reactive state when the challenge

In order to explore the model of ACC microglia response and activation during the development of mice from childhood to puberty (45 days after birth), the researchers injected lipopolysaccharide through intraperitoneal injection during the key time window (14 days) of mouse brain development (LPS) Establish an inflammation model

 

Experimental protocol for how early inflammation promotes depressive symptoms in adolescent mice

Experimental protocol for how early inflammation promotes depressive symptoms in adolescent mice

The study found that 6 hours after injection of LPS, multiple activation indicators of mouse ACC microglia increased significantly, and recovered after 24 hours
.

Interestingly, in the later stages of development, a series of unpredictable life stress events (such as weaning, cage breeding, noise, and fighting) may cause the ACC microglia of LPS mice to reactivate, making them more susceptible than normal mice

The study found that 6 hours after injection of LPS, multiple activation indicators of mouse ACC microglia increased significantly, and recovered after 24 hours

 Moreover, before stress, the sharp increase in ACCGlu activity helps mice resist the attack of stress and protect themselves

When the ACC microglia of LPS-treated mice were deleted or chemically inhibited, the mice did not exhibit depression-like behavior during puberty

In summary , the results of the study show that inflammation in early life can lead to the imbalance of microglia phagocytosis, which encodes the long-term maladaptation of ACCGlu neurons to stress, thereby promoting the development of depression-like symptoms in adolescence

 References :

 Peng Cao et al, Early-life inflammation promotes depressive symptoms in adolescence via microglial engulfment of dendritic spines,Neuron(2021).

 Peng Cao et al, Early-life inflammation promotes depressive symptoms in adolescence via microglial engulfment of dendritic spines,Neuron Neuron(2021).
DOI: 10.
1016/j.
neuron.
2021.
06.
012 DOI: 10.
1016/j.
neuron.
2021.
06.
012

 

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