A new study has confirmed the crucial relevance of gut bacteria to the human body and its role in the immune system. A mouse model revealed that levels of segmented filamentous bacteria can trigger changes in the lymphoid tissue in the gut resulting in production of antibodies that attack components of the cell nucleus. These symptoms are a characteristic of autoimmune diseases like systemic lupus erythematosus and systemic sclerosis.
“Our results demonstrate how gut health in young animals may be linked to autoimmune disease in older animals,” said Dirk Elewaut, Professor at Ghent University Hospital and the VIB Inflammation Research Center, Ghent University, Ghent, Belgium who is one of the lead authors of the study. “The microbiome of the young mouse impacts a loss of tolerance of the secondary immune system against proteins in the nucleus of the cell. The attack of certain proteins by the body’s own immune system can subsequently lead to tissue damage and disease.”
The mice model used were lacking secondary lymphoid organs including lymph nodes, tonsils and spleen. These organs play essential roles in the body’s immune system. One quarter of the affected mice spontaneously developed antibodies that would attack components of the cell nucleus. The increase in immune response was correlated to the presence of segmented filamentous bacteria in the gut of younger mice. Segmented filamentous bacteria are clostridia-related microorganisms found in the gut of many animals including mice, rats and humans.
“We have demonstrated a link between the microbiome of young mice and the later onset of autoimmune disease,” saidElewaut. “Further work is needed to establish the precise molecular mechanisms that leads to the onset of diseases like systemic lupus erythematosus and systemic sclerosis in humans but we now have a new path of enquiry that we can pursue and look for potential interventions.”
Jens T. Van Praet, Erin Donovan, Inge Vanassche, Michael B. Drennan, Fien Windels,Amélie Dendooven, Liesbeth Allais, Claude A. Cuvelier, Fons van de Loo, Paula S. Norris, Andrey A. Kuglov, Sergei A. Nedospasov, Sylvie Rabot, Raul Tito, Jeroen Raes, Valerie Gaboriau-Routhiau,Nadine Cerf-Bensussan, Tom Van de Wiele, Gérard Eberl, Carl F. Ware and Dirk Elewaut. Commensal microbiota influence systemic autoimmune responses. EMBO Journal, January 2015 DOI: 10.15252/embj.201489966