Disease-causing bacteria aided by immune system shift
Immune system defences against dangerous bacteria in the gut can be breached by turning off a single molecular switch that governs production of the protective mucus lining our intestinal walls, according to a study led by researchers at Yale University, the University of British Columbia (UBC), and the Weizmann Institute of Science.
Richard Flavell, Sterling Professor of Immunobiology at Yale’s Howard Hughes Medical Institute and co-senior author of the study, said: “This gut microbiota has been linked to the inflammation that triggers obesity, diabetes, metabolic disease, and most of chronic health problems of the Western world. We knew these invaders were causing problems, but we didn’t know how.”
The walls of the intestine are shielded from potentially harmful bacteria by a thin mucus lining, which has been described as the body’s demilitarised zone. The researchers found that production of this mucus lining depends upon a single immune system regulator, the NLRP6 inflammasome, which controls mucus secretion by cells in the wall of the intestine.
Mice lacking the inflammasome, where there is no mucus shield, were unable to fend off invaders. As a result, the intestinal wall becomes infected and inflamed, leaving the mice susceptible to conditions such as inflammatory bowel diseases, colon cancer, Type 2 diabetes, obesity and fatty liver disease. All these conditions stemmed from the bacterial invasion of the intestinal wall.
“The next step is to identify the bacteria in humans, prove that the system works the same way it does in mice, and figure out how to dial-up the protective shield,” Flavell said.
The research was part-funded by the European Research Council and results published in the journal Cell.
