The researchers at Harvard Medical School and Brigham and Women’s Hospital have developed a probiotic designed to suppress autoimmunity in the brain. Autoimmunity in the brain is a key factor in various neurodegenerative diseases, including multiple sclerosis (MS), where the immune system attacks the cells of the central nervous system.
In their study, conducted in mice and published in Nature on August 9, the researchers demonstrated the potential of the engineered probiotic in preclinical models of these diseases. They found that this technique offers a more precise way to target brain inflammation compared to standard therapies, while also minimizing negative side effects.
The engineered probiotic is designed to produce lactate, a molecule involved in many metabolic processes, to activate a biochemical pathway that acts as a brake for the immune system. By using synthetic biology to genetically engineer probiotic bacteria, the researchers aim to leverage the benefits of probiotics to address autoimmune diseases more effectively.
In experiments with mice that had a disease resembling MS, the researchers observed that the designer probiotic, residing in the gut, reduced the effects of the disease in the brain. Interestingly, the bacteria were not detected in the bloodstream of the mice, suggesting that the observed effects were a result of biochemical signaling between cells in the gut and the brain.
The researchers emphasize that further studies are needed to replicate these findings in larger models and, eventually, in humans. Despite the optimistic outlook, they acknowledge that mice are not perfect models for humans. However, the strain of bacteria used in creating the probiotic has already been tested in people, providing hope for potential translation of this approach into clinical use for treating autoimmune diseases in humans.
The team is also exploring modifications of this approach for autoimmune diseases affecting other parts of the body, particularly focusing on gut diseases like inflammatory bowel syndrome. The researchers highlight the potential of using living cells as a source of medicine in the body, envisioning more personalized and precise therapies for various autoimmune conditions.
