Msystem: too much pressure causes bacteria to cause autoimmune diseases

May 15, 2019 / BIOON / - life's stress events are likely to cause autoimmune diseases, but scientists have not fully understood the potential chain reaction of these events A study of mice published this week in the journal m systems suggests that gut microbiota may play an important role in this The researchers found that the presence of stress can cause changes in gut bacteria, which in turn stimulate the activity of immune cells and increase their potential to attack themselves Autoimmune disease is a disease that the immune system attacks its own tissues and systems The factors behind it are difficult to determine, partly because the severity and manifestation of these diseases are different They include multiple sclerosis, lupus, rheumatoid arthritis, juvenile diabetes, scleroderma, and pulmonary fibrosis The National Institutes of health estimates that more than 20 million people in the United States have autoimmune diseases, the vast majority of them women Source: msystem although researchers have identified some genetic risks, autoimmune diseases are believed to be caused by complex interactions between genetic and environmental factors In the study, published in the Journal mssystems, Orly Avni, Ph.D., an immunologist at Bar Ilan University, worked with graduate student Michal werbner and other collaborators to investigate environmental risks such as psychological and social stress, which provide opportunities for potential therapies "We know that there is a strong interaction between the immune system and the microbiota," Avni said An important step in understanding how stress causes autoimmune diseases is to determine the genetic response of bacteria, she said Her team's research shows that social stress changes the composition and transcription patterns of the microbiota "The ensuing immune response to this threat undermines self tolerance," she said "The researchers studied two groups of mice One of the mice was under daily pressure to make dangerous contact with other dominant and aggressive mice The other group did not After 10 days, the researchers analyzed the intestinal microflora of each group of mice and found that some bacteria in stressed mice were higher These microorganisms, including diphilus and desalting bacteria, are extremely abundant in patients with multiple sclerosis However, Avni said she was as interested in bacterial behavior as she was in ingredients Studies have shown that stress causes the activation of bacterial genes, which are associated with potential violent behavior, including growth, movement, and signaling between pathogens and their hosts Microbes with these characteristics can spread to other parts of the body, including lymph nodes, and trigger an immune response When the researchers analyzed the lymph nodes of stressed mice, they found an increase in the number of several known pathogens They also found a higher proportion of effector T cells known to play a role in autoimmunity These findings suggest that stress can lead to changes in intestinal microbial activity, which in turn can affect immune response and ultimately lead to physical attack The study shows that gut bacteria can sense and respond to social stress, but Avni points out that researchers need to better understand how this long-term interaction between bacteria and their hosts works "It's not enough to study the composition, increase or decrease of a species," she said We also have to understand how the microbiota perceive us and how they change their 'behavior' accordingly "She added that this knowledge could lead to tailored microbial interventions that inhibit autoimmunity and additional stress-induced disease Reference: Orly Avni et al Social stress responsive microbiota effects simulation of self reactive effector T helper cells Mssystem Doi: 10.1128/mssystems.00292-18