Poster Presentation CD1-MR1 Workshop 2025

Identification of self-metabolites as MR1 ligands and autoantigens in Type 1 diabetes (#115)

Lucía Mosquera-Ferreiro 1 2 , Alejandro Briones-Contreras 1 2 , Sofía Carreira-Santos 1 2 , Ana Ramírez-Iglesias 1 2 , Martin Kotrulev 1 2 , Beatriz García-Pinel 1 2 , Miguel A. Martínez-Olmos 3 , Teresa Martinez-Ramonde 4 , Paloma Cabanas 5 , Tommi Suvitaival 6 , Cristian Munteanu 7 , Hugo Gutiérrez de Teran 8 , Iria Gomez-Tourino 1 2
  1. Centre for Research in Molecular Medicine and Chronic Diseases (CiMUS). University of Santiago de Compostela, Santiago de Compostela, Spain
  2. Foundation Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain
  3. Department of Endocrinology and Nutrition, Complejo Hospitalario Universitario de Santiago, Santiago de Compostela, Spain
  4. Department of Endocrinology and Nutrition, Complejo Hospitalario Universitario de A Coruña, A Coruña, Spain
  5. Department of Pediatrics, Complejo Hospitalario Universitario de Santiago, Santiago de Compostela, Spain
  6. Steno Diabetes Center Copenhagen, Systems Medicine, Herlev, Denmark
  7. CITIC-Research Center of Information and Communication Technologies, Universidade da Coruña, A Coruña, Spain
  8. Nanomaterials and Nanotechnology Research Center (CINN), Spanish National Research Council (CSIC), Health Research Institute of Asturias (ISPA), Oviedo, Spain

Background

Mucosal invariant T (MAIT) cells recognize metabolites presented by the non-classical MHC class I protein MR1. Several factors implicate these cells in autoimmune diseases, including Type 1 diabetes (T1D), due to their proinflammatory profile, wide-spread tissue distribution and effector-memory phenotype. They can kill cells presenting cancer-related metabolites and self-metabolites, including beta cells, but the identity of these self-metabolites remains to be elucidated.

Aim

To identify which self-metabolites are MR1 ligands and can constitute MAIT autoantigens in the context of T1D.

Methods

We gathered information from three different sources to identify metabolites related with T1D and beta cell stress. Using untargeted metabolomics, we identified beta cell stress related metabolites in EndoC-βH1 cells following treatment with IFN-α or IFN-γ. We also performed a literature review and selected small metabolites that are differentially produced by T1D patients or stressed beta cells.  Finally, we also selected metabolites from plasma of T1D patients measured under the INNODIA consortium. We evaluated MR1 binding, followed by MAIT cell activation and blocking and competition assays. Finally, we performed FluoroSpot assays.

Results

The treatment with IFN-α or IFN-γ increases MR1 surface protein expression in Endoc-βH1 cells and induces differences on several cell metabolite levels. Activation assays indicate that some of the selected metabolites can bind MR1 in vitro and activate MAIT TCR-transduced Jurkat and primary MAIT cells. Blocking and competition assays show that the response is MR1-specific. FluoroSpots in primary peripheral blood mononuclear cells indicate that some metabolites can specifically activate MAIT cells and induce IFN-γ secretion.

Conclussions

We identified some beta-cell derived metabolites that are MR1 ligands and activate MAIT cells in a TCR-dependent manner. Current and future work includes elution of self-metabolites from beta-cell derived MR1 and evaluation of the phenotype of autoantigen-specific MAIT cells in peripheral blood of T1D patients.