Zombie genes?
According to a new study by the University of Illinois at Chicago, some brain cells increase their activity after death and grow to gigantic sizes.
The researchers analyzed gene expression in brain tissue that had been excised during brain surgery, several times after removal, to simulate the postmortem interval and death. They found that gene expression in some cells increased after death.
The "zombie genes" that increase expression after the postmortem period were specific to certain cells–glial cells, usually active during inflammation. The researchers noticed that glial cells grow and form long processes for many hours after death. This is not surprising, given that they are inflammatory, and their job is to clean the brain of dead tissues after damage, for example, stroke.
According to team leader Jeffrey A. Loeb, most studies that use postmortem human brain tissue to find treatments for disorders such as autism, schizophrenia and Alzheimer's disease do not take into account postmortem gene expression or cellular activity. Scientists assume that all processes in the brain stop after death, so the data on zombie genes will be useful for interpreting studies of human brain tissue.
Proliferation of glial cells after brain death.
Jeffrey Loeb is the director of UI NeuroRepository, a bank of human brain tissue from patients with neurological disorders who have agreed to collect and store tissue for research either after their death or after surgery. For example, during surgical treatment of epilepsy, pathological brain tissue is removed, part is necessary for pathological diagnosis, the rest can be used for research. Loeb and his colleagues analyzed such tissue samples in their work.
They found that about 80% of the analyzed genes remained relatively stable for 24 hours – their expression did not change. These include genes that provide basic cellular functions and are commonly used in scientific research to show tissue quality.
Another group of genes present in neurons and actively involved in the activity of the human brain, including memory, thinking and convulsive activity, degraded within a few hours after death. These genes are especially important for scientists studying disorders such as schizophrenia and Alzheimer's disease.
The third group of genes are the "zombie genes", which increased their activity when the others faded away. The peak of postmortem changes came about 12 hours later.
Thus, it is now known which genes and cell types are stable, which degrade, and which are activated over time, and this will help to better understand and interpret the results of postmortem brain studies more correctly.
Article F.Dachet et al. Selective time-dependent changes in activity and cell-specific gene expression in human postmortem brain is published in the journal Scientific Reports.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on UIC Today: 'Zombie' genes? Research shows some genes come to life in the brain after death.