A team of researchers has developed a new technique to study factors that can lead to cell death more easily, in conditions including neurodegenerative diseases.

It is difficult to determine when a brain cell has died, the researchers say, as neurons that appear inactive under the microscope can go on in a state of pause between life and death for several days, and some suddenly start sending signals again after appearing dormant.

For researchers studying neurodegeneration, the lack of an accurate declaration of the “time of death” of neurons makes it difficult to identify the factors that lead to cell death and to examine drugs that might save aging cells from dying.

A team from the Gladstone Institutes has developed a new technology that allows them to track thousands of cells simultaneously and determine the exact moment of death for any cell in the group.

In a paper published in Nature Communications, the team shows that this approach works in rodents and human cells as well as inside live zebrafish, and can be used to monitor cells over weeks to months.

“Determining an accurate time for cell death is very important for revealing cause and effect in neurodegenerative diseases,” explained Steve Finkbeiner, MD, director of the Center for Systems and Therapeutics at Gladstone. They are coping mechanisms that delay death.”

In an accompanying paper published in Science Advances, the researchers combined cell sensor technology with a machine learning approach, teaching a computer how to distinguish between living and dead cells 100 times faster and more accurately than a human.

Dr Jeremy Linsley, a participant in the science-leading program at Finkbeiner Lab, and lead author of the two papers revealed: ‘It took college students months to manually analyze this type of data, and our new system is almost instantaneous, actually working faster than we can get new images on. microscope”.

When cells die, whatever the cause or mechanism, they eventually become fragmented and their membranes deteriorate. But this decomposition process takes time, making it difficult for scientists to distinguish between cells that have long ceased to function, diseased and dying cells, and healthy cells.

Researchers usually use fluorescent markers or dyes to follow diseased cells under a microscope over time and try to diagnose where they are in this decay process.

“We really wanted an indicator that would last the entire life of the cell, not just a few hours, and then give a clear signal only after the exact moment the cell dies,” says Linsley.

Linsley, Finkbeiner and their colleagues chose calcium sensors, originally designed to track calcium levels inside a cell.

When the cell dies and its membranes become leaky, one side effect is that calcium rushes into the aqueous cytosol, which usually contains relatively low levels of calcium.

So, Linsley designed calcium sensors to sit in the cytosol, glowing only when calcium levels rise to a level that indicates cell death.

The new sensors, known as a genetically encoded death indicator (GEDI), can be inserted into any cell type and indicate that a cell is alive or dead for the entire life of the cell.

The team correlated the results from the new sensor with standard fluorescence data on the same neurons, and taught a computer model, called BO-CNN, to identify typical glow patterns associated with what the dying cells look like.

The researchers showed that the model was 96 percent accurate and better than what human observers could do, and was 100 times faster than previous methods for distinguishing between living and dead cells.

Both GEDI and BO-CNN will allow researchers to conduct new, high-throughput studies to discover when and where brain cells die, a very important end point for some diseases.

They can also test drugs for their ability to delay or avoid cell death in neurodegenerative diseases. Or, in the case of cancer, they can look for drugs that speed up the death of diseased cells.

“These technologies are game-changing in our ability to understand where, when and why cell death occurs,” Finkbeiner says. “For the first time, we can really take advantage of the speed and scale offered by advances in robot-assisted microscopy to more accurately detect cell death, and do so long before Death. Hopefully, this will lead to more specific treatments for many neurodegenerative diseases that have hitherto been incurable.”