The gut microbiota has an influence on many aspects of health, with recent research confirming the microbiota has an effect on the central nervous system and could potentially play a role in brain function, as well as helping to control the immune system, allow energy recovery from the metabolism of nondigestible food components, and also helps regulate gut endocrine function.
A new study has now shed light on the role the gut microbiota has on inflammatory diseases including multiple sclerosis (MS), rheumatoid arthritis (RA), ulcerative colitis (UC) and Crohn’s disease (CD). Researchers at Université Laval in Quebec City have discovered a naturally occurring protein in the gut causes the microbiota to release molecules that have systemic effects on the immune system, which exacerbates the symptoms of inflammatory diseases such as MS, RA, UC, and CD
sPLA2-IIA has previously been detected in the synovial fluid of the joints of individuals with arthritis, and also in significant quantities in the gut. The researchers recently discovered sPLA2-IIA exhibits antimicrobial activity, although does not interact with human cells. The phospholipase has a high affinity for bacterial membranes and binds and splits those membranes, which results in small molecules from inside those bacteria being released. The bacteria release molecules such as fatty acids which have been shown to exacerbate chronic inflammation. In experiments on mice, the researchers demonstrated proinflammatory lipids significantly increased inflammation and the severity of arthritis symptoms.
Eric Boilard, a professor in the Université Laval’s Faculty of Medicine CHU de Québec–Université Laval Research Centre researcher said his team has been working closely with another research team led by Makoto Murakami of the University of Tokyo which found that the action of the phospholipase on the gut microbiota of mice exacerbated psoriasis and skin cancer.
Together their research suggests it may be possible to alleviate the symptoms of patients with systemic inflammatory diseases by blocking the proinflammatory lipids released by bacteria into the gut. Boilard and his team are now looking to test this theory on patients with arthritis to see if symptoms can be relieved by blocking bacterial proinflammatory lipids.
You can read more about the study in the paper – The interaction of secreted phospholipase A2-IIA with the microbiota alters its lipidome and promotes inflammation – which was recently published in the Journal of Clinical Investigation. DOI: 10.1172/jci.insight.152638.