“Zombie genes” increase postmortem brain activity

A surprising new study found that gene expression can increase dramatically in some brain cells hours after a person dies. These “zombie genes” are primarily associated with inflammatory activity, and researchers suggest that scientists studying postmortem brain tissue need to take these important changes into account. ..

We generally mark the moment of death of a person as when the heart beats. Many scientific studies investigating post-mortem tissue work on the assumption that everything will stop when we die. However, a series of small but growing studies reveal many cellular activities and gene expressions that occur hours and days after human death.

A fascinating recent study is a large amount Genes can be switched on After the creature dies. However, much of this research focuses on animal tissues of various organs. This new study focuses specifically on human brain tissue and has resulted from some unusually inconsistent observations.

The corresponding author of the new study, Jeffrey Robe, is the director of the UI Neurorepository at the University of Illinois at Chicago, and his team manages a library of human brain tissue collected from consent patients with neurological disorders.

The research team has the advantage of being able to analyze brain tissue incredibly quickly after collection. Looking at the patterns of gene expression in fresh human brain tissue, they noticed a significant difference between what they were seeing and the publicly available gene expression data in brain tissue.

“We are simulated by examining the expression of all human genes at 0-24 hours from a large block of recently collected brain tissue left at room temperature to reproduce postmortem changes. I decided to carry out a death experiment. Intervals, ”explains Loeb.

The tissue robe and his team used in the new study came from an epilepsy patient undergoing surgery to reduce seizures. This allowed researchers to investigate temporal changes in gene expression in brain tissue from the moment of collection.

Most of the genes in the brain tissue analyzed did not change much over the 24-hour study period. However, small amounts of “zombie genes” actually increased activity during these post-mortem hours. These genes with increased activity were directly associated with glial cells, a particular type of immune cell in the brain.

Loeb suggests that it is not particularly surprising to see the activity of this type of immune gene in the postmortem brain. After all, these cells respond directly to brain damage. But what is noteworthy is the enormous amount of activity that occurs in the hours following death. This study shows that the pattern of gene expression peaks about 12 hours after death, but activity is observed at least 24 hours after tissue resection.

The big point from this new study is for researchers investigating human brain tissue. Loeb requires that these findings allow post-mortem brain tissue studies to take into account important changes that can occur in post-mortem tissue, and researchers must attempt to study brain tissue near the time of human death. Is called.

“Our findings do not mean that human tissue research programs should be abandoned. It does mean that researchers take these genetic and cellular changes into account and postmortem intervals to reduce these scales. It means that you need to be as short as possible. It changes, “says Loeb. “The good news from our findings is that we know which genes and cell types are stable, which are degraded, and which increase over time so that we can better understand the results of postmortem brain studies. That is. “

New study published in journal Science report..

Source: UIC