Mutations in a gene associated with Crohn's disease have been found to rob critical immune cells of their ability to switch modes, causing them to overreact and trigger inflammation.

Variations in the NOD2 gene have been linked to Crohn's in previous studies, yet their exact role in the disease's pathology has long been a mystery.

Researchers from the University of California, San Diego used machine learning techniques to identify patterns in gene activity of immune cells in the gut.

Experiments on lab-grown cells and samples from both healthy guts and digestive tracts with a form of Crohn's called inflammatory bowel disease (IBD) revealed that the mutations interfere with typical protective mechanisms that allow NOD2 proteins to guard against IBD.

Tracking the behavior of immune cells called macrophages through the expression of their genes, the researchers discerned which cells helped the gut stay healthy and which became inflammatory and caused damage.

"The gut is a battlefield, and macrophages are the peacekeepers," says UC San Diego Gajanan Katkar. "For the first time, AI has allowed us to clearly define and track the players on two opposing teams."