Keio University Researchers Identify Gut Epithelial Cells as Primary Initiators of Brain Inflammation in Multiple Sclerosis

Keio University researchers identify how gut epithelial cells prime Th17 cells to attack the brain in MS. Learn about the new 2026 gut-CNS axis discovery.

By: AXL Media

Published: Mar 28, 2026, 4:47 AM EDT

Source: Information for this report was sourced from Keio University Global Research Institute

The Gut-CNS Axis and the Origins of Autoimmunity

Multiple Sclerosis is fundamentally a disorder of mistaken identity, where the immune system attacks the protective myelin sheath of the brain and spinal cord. While genetic and environmental factors have long been studied, the Keio University team focused on the gut microenvironment as a potential staging ground for these attacks. According to Dr. Tomohisa Sujino, while the influence of gut microbes on neurological diseases like Parkinson's and Alzheimer's is well-documented, the specific relay system that carries inflammatory signals from the intestine to the brain has remained a medical mystery until now.

Intestinal Epithelial Cells as Unconventional Messengers

The study identified a surprising culprit in the initiation of neuroinflammation: intestinal epithelial cells (IECs). These cells, which form the lining of the gut, were found to overexpress Major Histocompatibility Complex class II (MHC II), a molecular "flagpole" used to present antigens to the immune system. Typically, IECs do not perform this function, but in patients with MS and in experimental models, these cells began actively priming CD4+ T cells. According to the research, this specific interaction in the ileum acts as the primary spark for the autoimmune response, long before symptoms appear in the central nervous system.

Polarization of Pathogenic Th17 Cells

Through sophisticated co-culture assays, the researchers proved that when IECs present antigens via MHC II, they force the polarization of T cells into a highly inflammatory state known as Th17. These Th17 cells are the primary drivers of the chronic inflammation seen in MS. The team discovered that by selectively deleting the MHC II gene in the intestinal lining of test subjects, they could significantly reduce the generation of these pathogenic cells and lessen the overall severity of the neurological disease. This suggests that the gut is not just a secondary site of inflammation but a critical training ground for the cells that eventually attack the brain.