Bacteria of the genus Lactobacillus, present in the intestinal microbiota, can interact with cells of the immune system and, thus, cause an increase in the intestinal barrier, according to an international study conducted by the Complutense University of Madrid (UCM) and the National Center for Cardiovascular Research. (CNIC), both institutions in Spain.
A study in mice and published in the journal Immunity opens up a new way of treating pathologies, such as ulcerative colitis or Crohn's disease, in which the intestinal barrier of an individual is so weakened that bacteria can invade other organs, causing inflammation.
So far, there are only a few examples of how certain specific mouse microbiota commensals stimulate the immune system and regulate the lymphocyte population, which contribute to the fact that bacteria remain only in the niche where they are useful.
“Our research shows that there are molecular patterns present or secreted by commensal intestinal bacteria that can be recognized by an immune system cell receptor called Mincle,” says Salvador Iborra, a researcher in the Department of Immunology, Ophthalmology and ORL UCM. ,
This interaction between Mincle and some beneficial bacteria of the genus Lactobacillus occurs in areas of the small intestine called Plates de Peyer, and promotes a favorable response to the host.
Peyer plate. (Photo: Salvador Iborra)
To conduct this study, experts used mice with a Minkle receptor deficiency or one of the proteins involved in the intracellular signal transduction of this receptor, called Syk.
Researchers may have noticed that because of this deficiency, the necessary instructions for generating intestinal lymphocytes necessary for regulating the function of the intestinal immune barrier were not obtained.
"As a consequence of the decrease in this population of lymphocytes, we observed a deterioration in the function of the intestinal barrier, which leads to an increase in the number of bacteria that can escape from the intestine and reach the liver, causing inflammation and metabolic changes there." explains Iborra.
According to the results of this study, a new strategy was discovered to reduce pathologies, such as “using probiotics of beneficial microorganisms that can interact with this receptor, or prebiotics that can stimulate the growth of these intestinal bacteria,” says a UCM researcher. Iborra also adds another possibility: treatment with synthetic compounds that can bind to Mincle and induce a favorable response mediated by this receptor.
In inflammatory bowel diseases, stress, unhealthy diet, or drug abuse are added as factors that can weaken the intestinal barrier.
In addition to UCM and CNIC, institutions from other countries, such as the University of Oxford, the University of Manchester, the University of Paris-Saclay, the University of Sorbonne or the University of Zurich, and others are participating in the study. (Source: UCM / DICYT)