Young people are generally feeling the pressure . A momentary fear of stress is a normal physical and psychological response in life, but this emotional response, that is, long-term stress, will adversely affect our health, prone to depression, anxiety.
Long-term stress is not only reflected in mood disorders, but may be a full-body breakdown behind it. According to a new study led by Professor Yu Jin of Zhejiang University and Professor Chai Renjie of Southeast University, the important cause of anxiety caused by long-term stress is that immune cells are first “overwhelmed” and have metabolic dysfunction! The study was recently published in the leading academic journal Cell.
Why does stress cause mood disorders in the brain and what role does the immune system play in the process? To answer this question, the researchers first tested the behavior of the experimental animals when they felt stress over a long period of time.
In the experiment, the mice were stimulated by foot shocks for eight consecutive days. Normal mice quickly showed behavioral anxiety after experiencing this stress, such as always turning around the wall when they were in an open field.
However, genes that lacked immune cells in the body knocked out mice, which behaved differently, and appeared to be much more slow to respond to stress. Further analysis found that auxiliary T cells (CD4-T cells) were particularly important in different immune cells. Taking CD4-T cells from anxious mice and transferring them to mice that were not stress-sensitive also made them anxious.
In the classic stress-anxiety mouse model, CD4-T cells are necessary for stress-induced anxiety (Photo: Supplied)
CD4-T cells are mainly present in the blood and immune organs, and the activation of other immune cells, such as B-cells, and the activation of cytotoxic T-cells is important to assist, and is our health guardian in the fight against infection.
However, in the case of long-term stress, these immune cells are surprisingly different! The researchers collected CD4-T cells from different mice and analyzed genes for cell expression. The results showed that when the mice were under long-term stress, the mitochondria, the “energy factory” in the CD4-T cells, were destroyed: they became more likely to split into pieces!
Mitochondria play an important role in the metabolic function of cells. As mitochondria are “crushed”, the normal glycoenzyme metabolism pathways of glucose in immune cells “deviate” and produce a large amount of niobium-like substances, which are released out of the cells.
Within cd4-T cells, the shape and metabolic function of the mitochondria change, producing a large amount of niobium (Photo: Resources 2)
The researchers found that these ferns can be the key to anxiety! In mice with destroyed particles online, the content of several ferns increased by 10 to 100 times compared to normal controls. Moreover, the jaundice (xanthine) can easily cross the blood-brain barrier and enter the brain from the peripheral immune system.
Using techniques such as single-cell sequencing, the researchers found in the brains of mice how jaundice works on the nervous system, and found that in the amygdala, a key brain region that deals with emotions such as fear and anxiety, there were a large number of receptors on the less progeniable glial cells that could be combined with jaundice, which would be stimulated by signals, activate related neurons, and trigger anxiety.
Illustration of this study (Image Source: Resources)
In addition, clinical evidence collected by the team showed that jaundice levels in serum were indeed higher in patients with anxiety disorders than in the control group. Their findings could help “to clinically design some quantitative indicators of blood testing in the future to judge the severity of anxiety disorders, and to provide an objective evaluation of the effectiveness of treatment, combined with the current clinical method of entering questionnaires to make the diagnosis more accurate,” according to Professor Yujin.
Combined with these results, the team identified a mechanism by which stress interferes with immune cells and metabolic abnormalities in immune cells that affect the brain’s mood and behavior. The work has also been highly praised by peers, with The Cell commenting: “This subtle study by Van Kirkiet et al. could offer potential new treatment options for patients with depressive symptoms due to immune system disorders.” “