Exploring novel therapies for celiac disease centered around the autoantigen transglutaminase 2

Cøliaki er en sykdom som rammer 1-2% av befolkningen. Den eneste eksisterende behandlingen for sykdommen i dag er en livslang glutenfri kost. Det er ønskelig å utvikle alternative behandlingsmetoder. Nyere forskning har avdekket at enzymet transglutaminase 2 spiller en sentral rolle i utviklingen av sykdommen. Dette enzymet forandrer glutenproteiner slik at immunsystemet hos cøliakere kan reagerer på disse proteinene. Denne immunresponsen hos cøliakere involverer B-celler. B-celler produserer antistoffer, og cøliakere har B-celler og antistoffer som er rettet mot transglutaminase 2. I projektet ønsker vi å ta denne kunnskapen i retning mot utvikling av nye behandlingsprinsipper. En del av prosjektet dreier seg om hemming av enzymaktiviteten til transglutaminase 2, og å avdekke hvor i kroppen hvor transglutaminaseaktiviteten bør hemmes. En annen del av prosjektet dreier seg om å finne en metode som kan elimimere B-cellene som gjenkjenner transglutaminase 2. Prosjektet vil studere celler og vev fra cøliakere samt mus som er genetisk modifisert til å uttrykke reseptorer som brukes av cøliakere til å gjenkjenne gluten og transglutaminase 2.

Celiac disease is a prevalent autoinflammatory condition caused by immune reaction to dietary gluten proteins. The only available treatment is lifelong avoidance of dietary gluten. However, symptoms and enteropathy often persist in patients who attempt to adhere to a gluten-free diet. Thus, there is a need to develop non-dietary therapies for celiac disease. The enzyme transglutaminase 2 (TG2) has critical roles in celiac disease pathogenesis. The enzymatic activity of TG2 creates by deamidation gluten peptides that have high affinity for disease-predisposing HLA-molecules, and these deamidated peptides are recognized by the disease-driving CD4+ T cells. Moreover, TG2 is the target of a highly specific autoantibody response. In this project we will explore two novel treatment avenues focused on TG2. In the first approach, we seek to develop novel immunotherapeutic molecules, Bispecific AutoAntigen T-cell Engagers (BiAATEs), to specifically eliminate the subset of autoreactive TG2-specific B cells while avoiding general immunosuppression. The results will be important not only for celiac disease but also for other autoimmune diseases having cytosolic autoantigens. Second, we will explore therapeutic inhibition of TG2. ZED1227, an irreversible inhibitor of TG2, was recently shown in a phase 2 clinical trial to prevent gluten-induced intestinal damage in celiac disease patients. It is however unknown where in the body the drug is active. Our group has obtained evidence that the gut lumen likely is the relevant site where TG2 is active and encounters gluten peptides for deamidation. We will test the new hypothesis that TG2 in gut lumen is pathogenic in celiac disease and will explore inhibition of gut luminal TG2 as therapy. Both arms of the project will combine studies on patient samples with mechanistic experiments in state-of-the art humanized mouse models that we recently developed.