Scientific highlights

04.01.2018

Autoimmune Reaction Successfully Halted in Early Stage Islet Autoimmunity

Scientists at Helmholtz Zentrum München have discovered a mechanism that amplifies the autoimmune reaction in an early stage of pancreatic islet autoimmunity prior to the progression to clinical type 1 diabetes. If the researchers blocked the corresponding molecules, the immune system was significantly less active. The study was conducted under the auspices of the German Center for Diabetes Research (DZD) and was published in the journal ‘Science Translational Medicine’.

T cells after stimulation in the presence of a miRNA181a mimic. Immunofluorescent staining of the T cell marker CD4 (green), the transcription factor NFAT5 (red) and the nucleus (blue). The stimulation in the presence of a miRNA181a mimics results in an increase of NFAT5 expression in T cells. Source: Helmholtz Zentrum München

Type 1 diabetes is the most common metabolic disease in childhood and adolescence. In this disease, the body's own immune system attacks and destroys the insulin-producing cells of the pancreas. Regulatory T cells (Tregs) play an important role in this process: In healthy people, they suppress excessive immune reactions and thus prevent autoimmune diseases. 

Dr. Carolin Daniel's team is investigating why Tregs fail to protect the islet cells in type 1 diabetes. She is a group leader at the Institute for Diabetes Research (IDF) of Helmholtz Zentrum München and a scientist in the DZD. In the current study, she and her team elucidated a mechanism that causes fewer Tregs to be produced during islet autoimmunity onset and that therefore allows the immune system to get out of control and attack.

According to the findings of the study, miRNA181a and NFAT5 molecules play a key role. "We showed that miRNA181a leads to the activation of the transcription factor NFAT5 during islet autoimmunity onset," said Daniel.* “The consequence is an inhibition of Treg induction and thus increased immune activation.“ 


Axis pharmacologically interrupted

In order to test the suitability of this new finding for possible therapeutic approaches, the scientists led by the first author Isabelle Serr investigated a preclinical model with early-stage islet autoimmunity. If the researchers interrupted the miRNA181a/NFAT5-axis, they observed a significantly lower activation of the immune system and an increased formation of Tregs. This was achieved both by the pharmacological inhibition of miRNA181a as well as of NFAT5.

"The targeted inhibition of miRNA181a or NFAT5 could open up new approaches to reduce the activity of the immune system against its own islet cells," said Professor Anette-Gabriele Ziegler, director of the IDF. "The combination with other immune modulating therapeutic approaches would also be conceivable as an intervention.”

In the future, the scientists want to further investigate these findings in preclinical tests. To this end, humanized models will be used to test whether the combination of insulin vaccination and inhibition of the miRNA181a/NFAT5 axis leads to a more tolerant immune system towards insulin-producing cells. 

Further Information

* The researchers suspect indirect mechanisms such as the inhibition of phosphatase PTEN. 

Background: 
“The cooperation with Benno Weigmann's group at the University Hospital Erlangen-Nuremberg was important for the success of the research,” said Carolin Daniel. With her research group “Immunological Tolerance in Diabetes,” she is investigating the role of regulatory T cells in type 1 diabetes. She tells more in theresearch portrait, which includes a video interview, in which she explains how the disease develops and her strategy against it. The video Type 1 Diabetes: Development and Preventionwas produced by the Diabetes Information Service Munich (only available in German).  

Original Publication:
Serr, I. et al. (2017): A miRNA181a/NFAT5 axis links impaired T cell tolerance induction with autoimmune Type 1 diabetes. Science Translational Medicine
DOI: 10.1126/scitranslmed.aag1782


As German Research Center for Environmental Health, Helmholtz Zentrum München pursues the goal of developing personalized medical approaches for the prevention and therapy of major common diseases such as diabetes mellitus and lung diseases. To achieve this, it investigates the interaction of genetics, environmental factors and lifestyle. The Helmholtz Zentrum München has about 2,300 staff members and is headquartered in Neuherberg in the north of Munich. Helmholtz Zentrum München is a member of the Helmholtz Association, a community of 18 scientific-technical and medical-biological research centers with a total of about 37,000 staff members. 

The Institute of Diabetes Research (IDF) focuses on the pathogenesis and prevention of type 1 diabetes and type 2 diabetes and the long-term effects of gestational diabetes. A major project is the development of an insulin vaccination against type 1 diabetes. The IDF conducts long-term studies to examine the link between genes, environmental factors and the immune system for the pathogenesis of type 1 diabetes. Findings of the BABYDIAB study, which was established in 1989 as the world’s first prospective birth cohort study, identified risk genes and antibody profiles. These permit predictions to be made about the pathogenesis and onset of type 1 diabetes and will lead to changes in the classification and the time of diagnosis. The IDF is part of the Helmholtz Diabetes Center (HDC). 

The German Center for Diabetes Research (DZD) is a national association that brings together experts in the field of diabetes research and combines basic research, translational research, epidemiology and clinical applications. The aim is to develop novel strategies for personalized prevention and treatment of diabetes. Members are Helmholtz Zentrum München – German Research Center for Environmental Health, the German Diabetes Center in Düsseldorf, the German Institute of Human Nutrition in Potsdam-Rehbrücke, the Paul Langerhans Institute Dresden of the Helmholtz Zentrum München at the University Medical Center Carl Gustav Carus of the TU Dresden and the Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Zentrum München at the Eberhard-Karls-University of Tuebingen together with associated partners at the Universities in Heidelberg, Cologne, Leipzig, Lübeck and Munich.

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