Killer cell proteins suppress listeria without killing cells

[ad_1]

A new study from North Carolina State University shows that key proteins known to prevent viral infections by inducing cell death can also block certain bacterial infections without causing death of host cells.

Rather than killing host cells infected with Listeria In the gastrointestinal tract, the RIPK3 and MLKL proteins recognize the chemical composition of the bacteria and the MLKLs attach to it, thus preventing the spread of the bacteria. Listeria while keeping the host cells alive.

"We have shown that these proteins perform a different function in intestinal epithelial cells compared to immune cells, but we still do not know how and why this differentiation occurs," said Jun Ninomiya-Tsuji, professor of biological sciences and Corresponding co-author of an article describing the research.

The researchers, led by Kazuhito Sai, toxicology research badociate and corresponding article author, first used human intestinal cells to show that RIPK3-deficient cells were infected with Listeria while cells with RIPK3 had few infections of this type. The researchers then used mice to see if Listeria could reach the liver of mice by invading intestinal cells. They found a lot Listeria in mice with RIPK3 deficiency but few Listeria in normal mice.

They then showed that RIPK3 and a protein that works with, MLKL, were activated by the presence of Listeria. This activation of the inhibited protein pathway Listeria replication, showing that the proteins actually blunt Listeria.

Then, surprisingly, the researchers showed that the activation of RIPK3 and MLKL by Listeria did not result in cell death. Instead, the MLKL proteins linked to Listeria, stopping its spread.

"These proteins induce cell death to prevent certain infections, especially in immune cells," said Sai. "Inducing the death of epithelial cells in the gastrointestinal tract can result in the elimination of an important barrier against viruses and bacteria, so it is possible that these proteins recognize that their destruction could worsen the situation at the site. place to improve it. "

Future research will attempt to understand how and why these proteins adopt different approaches – inducing or not inducing cell death – to prevent bacteria from the gastrointestinal tract, the researchers said.

Cameron Parsons, Postdoctoral Fellow, John S. House, Bioinformatics Researcher, and Sophia Kathariou, Professor of Food, Bioprocessing and Nutrition Sciences, co-authored the paper published online in the Journal of Cell Biology.