Mar 25, 2021 20:15:00

A 'zombie gene' that begins activity after death is found in the human brain

On March 23, 2021,

Jeffrey Loeb and colleagues at the University of Illinois revealed that genes in the brain that activate after human death and promote cell growth are also present.

Selective time-dependent changes in activity and cell-specific gene expression in human postmortem brain | Scientific Reports
https://www.nature.com/articles/s41598-021-85801-6

'Zombie' genes? Research shows some genes come to life in the brain after death | UIC Today
https://today.uic.edu/zombie-genes-research-shows-some-genes-come-to-life-in-the-brain-after-death

When humans die, the circulation of oxygen by the blood ceases, and cells in the body rapidly cease to operate. However, a 'zombie gene' that activates after death and promotes cell growth was discovered in mice and zebrafish in 2016, and it was later revealed that this zombie gene is also present in the human body. ..

Loeb et al. Compare fresh human neocortex removed by epilepsy surgery with dead human neocortex to understand human neuropsychiatric disorders. The pattern and gene expression level when DNA was transcribed into mRNA were analyzed using RNA sequence (RNA-Seq). As a result, genes such as nerve cells (neurons) that make up the nervous system rapidly lose their activity, while genes in some cells become active. This gene is the zombie gene mentioned above.

The zombie gene showed a particularly peculiar function in another group of cells 'glial cells ' that make up the nervous system, and the glial cell expressing the zombie gene sprouted something like a long arm for several hours after death. It was confirmed that.

In addition, to explore the relationship between cell expression and the time since brain cells were removed, the research team

stained fresh human cells and observed them over time. As a result, neurons decrease significantly 24 hours after cell removal, whereas 'astrocytes ' and ' microglia ', which are one type of glial cells and function as immune cells that protect the brain and spinal cord, are It was confirmed that the cells were activated 4 hours after removal and reached the peak activity 12 hours later.

The gene group that expressed glial cells after death is known as 'zombie cells', and its existence has been confirmed in the human body so far, but this experiment suggests that it also exists in the brain. I did.

Glial cells have the function of removing waste products such as broken nerve cells after brain damage caused by oxygen deficiency or stroke. 'Glial cells have the property of being inflammatory in response to physical stimuli, so it's not surprising that they are still active after death,' Loeb et al. On the other hand, many experts who have studied the human brain after death do not think that 'genes expressed after death' or 'brain cells activated after death' exist in the brain, so in the human brain. Loeb pointed out that this discovery, which elucidated the functions of zombie genes and zombie cells, deserves special mention.

On top of that, Loeb et al. 'Most studies assume that when the heart beats stop, all activity in the brain stops, but in consideration of this discovery, we decided to study the brain. Should use brain tissue as soon as possible after death. ' This study was possible because Mr. Loeb, who is in charge of the UI NeuroRepository , which stores the brain tissue of patients suffering from neurological diseases, agreed with the brain tissue used in the experiment. It is said that it was provided by obtaining.