Fecal Detection of Calprotectin Subunits Links Inflammatory Bowel Disease Activity With Chronicity of Intestinal Inflammation

Almina Jukic; Richard Hilbe; Luis Zundel; Peter Willeit; Klaus Faserl; Christina Plattner; Andreas Zollner; Moritz Meyer; Kerstin Siegmund; Victoria Klepsch; Valentin Marteau; Arnau Vich Vila; Julian Schwärzler; Kathrin Vouk; Anna Kozsar; Dietmar Rieder; Amos Weichberger; Bettina Sarg; Felix Grabherr; Lisa Mayr; Patrizia Moser; Niloofar Nemati; Sabine Scholl-Bürgi; Daniela Karall; Georg F Vogel; Lina Welz; Denise Aldrian; Robert Koch; Alexandra Pfister; Qitao Ran; Arthur Kaser; Richard S Blumberg; Ivan Tancevski; Felix Sommer; Petra Bacher; Stefan Schreiber; Philip Rosenstiel; Konrad Aden; Gottfried Baier; Latifa Bakiri; Thomas Müller; Günter Weiss; TRR241 IBDome Consortium; Rinse K Weersma; Zlatko Trajanoski; Erwin F Wagner; Herbert Tilg; Timon E Adolph

doi:10.1053/j.gastro.2025.08.040

Fecal Detection of Calprotectin Subunits Links Inflammatory Bowel Disease Activity With Chronicity of Intestinal Inflammation

Gastroenterology. 2025 Nov 26:S0016-5085(25)05987-6. doi: 10.1053/j.gastro.2025.08.040. Online ahead of print.

Authors

Almina Jukic¹, Richard Hilbe², Luis Zundel¹, Peter Willeit³, Klaus Faserl⁴, Christina Plattner⁵, Andreas Zollner¹, Moritz Meyer¹, Kerstin Siegmund⁶, Victoria Klepsch⁶, Valentin Marteau⁵, Arnau Vich Vila⁷, Julian Schwärzler¹, Kathrin Vouk¹, Anna Kozsar¹, Dietmar Rieder⁸, Amos Weichberger⁹, Bettina Sarg⁴, Felix Grabherr¹, Lisa Mayr¹, Patrizia Moser¹⁰, Niloofar Nemati⁵, Sabine Scholl-Bürgi¹¹, Daniela Karall¹¹, Georg F Vogel¹², Lina Welz¹³, Denise Aldrian¹¹, Robert Koch¹, Alexandra Pfister¹, Qitao Ran¹⁴, Arthur Kaser¹⁵, Richard S Blumberg¹⁶, Ivan Tancevski², Felix Sommer¹³, Petra Bacher⁹, Stefan Schreiber¹³, Philip Rosenstiel¹³, Konrad Aden¹³, Gottfried Baier⁶, Latifa Bakiri¹⁷, Thomas Müller¹¹, Günter Weiss²; TRR241 IBDome Consortium; Rinse K Weersma⁷, Zlatko Trajanoski⁵, Erwin F Wagner²⁸, Herbert Tilg²⁹, Timon E Adolph³⁰

Collaborators

TRR241 IBDome Consortium:
Imke Atreya¹⁸, Raja Atreya¹⁸, Petra Bacher¹⁹, Christoph Becker¹⁸, Christian Bojarski²⁰, Nathalie Britzen-Laurent¹⁸, Caroline Bosch-Voskens¹⁸, Hyun-Dong Chang²¹, Andreas Diefenbach²², Claudia Günther¹⁸, Ahmed N Hegazy²⁰, Kai Hildner¹⁸, Christoph S N Klose²², Kristina Koop¹⁸, Susanne Krug²⁰, Anja A Kühl²⁰, Moritz Leppkes¹⁸, Rocío López-Posadas¹⁸, Leif S-H Ludwig²³, Clemens Neufert¹⁸, Markus Neurath¹⁸, Jay Patankar¹⁸, Magdalena Prüß²⁴, Andreas Radbruch²¹, Chiara Romagnani²⁴, Francesca Ronchi²², Ashley Sanders²⁵, Alexander Scheffold²⁶, Jörg-Dieter Schulzke²⁰, Michael Schumann²⁰, Sebastian Schürmann¹⁸, Britta Siegmund²⁰, Michael Stürzl¹⁸, Antigoni Triantafyllopoulou²⁷, Maximilian Waldner¹⁸, Carl Weidinger²⁰, Stefan Wirtz¹⁸, Sebastian Zundler¹⁸

Affiliations

¹ Department of Internal Medicine I, Gastroenterology, Hepatology, Endocrinology & Metabolism, Medical University of Innsbruck, Innsbruck, Austria.
² Department of Internal Medicine II, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Innsbruck, Austria.
³ Institute of Clinical Epidemiology, Public Health, Health Economics, Medical Statistics and Informatics, Medical University of Innsbruck, Innsbruck, Austria; Department of Public Health and Primary Care, University of Cambridge, Cambridge, United Kingdom.
⁴ Biocenter, Protein Core Facility, Institute of Medical Biochemistry, Medical University of Innsbruck, Innsbruck, Austria.
⁵ Biocenter, Institute of Bioinformatics, Medical University of Innsbruck, Innsbruck, Austria.
⁶ Institute of Cell Genetics, Medical University of Innsbruck, Innsbruck, Austria.
⁷ Department of Gastroenterology and Hepatology, University of Groningen and University Medical Center of Groningen, Groningen, the Netherlands.
⁸ Biocenter, Institute of Bioinformatics, Medical University of Innsbruck, Innsbruck, Austria; Biocenter, Bioinformatics Core Facility, Medical University of Innsbruck, Innsbruck, Austria.
⁹ Institute of Clinical Molecular Biology, Christian Albrecht University Kiel and Schleswig-Holstein University Hospital, Kiel, Germany; Institute of Immunology, Christian Albrecht University Kiel and Schleswig-Holstein University Hospital, Kiel, Germany.
¹⁰ INNPATH, Innsbruck Medical University Hospital, Innsbruck, Austria.
¹¹ Department of Pediatrics I, Medical University of Innsbruck, Innsbruck, Austria.
¹² Department of Pediatrics I, Medical University of Innsbruck, Innsbruck, Austria; Institute of Cell Biology, Medical University of Innsbruck, Innsbruck, Austria.
¹³ Institute of Clinical Molecular Biology, Christian Albrecht University Kiel and Schleswig-Holstein University Hospital, Kiel, Germany.
¹⁴ Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, Texas.
¹⁵ Cambridge Institute of Therapeutic Immunology and Infectious Disease, Department of Medicine, University of Cambridge, Cambridge, United Kingdom.
¹⁶ Gastroenterology Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
¹⁷ Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria.
¹⁸ Department of Medicine 1, Friedrich-Alexander University, Erlangen, Germany.
¹⁹ Institute of Clinical Molecular Biology, Christian-Albrecht University of Kiel, Kiel, Germany; Institute of Immunology, Christian-Albrecht University of Kiel and Universitätsklinikum Schleswig-Holstein, Kiel, Germany.
²⁰ Department of Gastroenterology, Infectious Diseases and Rheumatology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.
²¹ Deutsches Rheuma-Forschungszentrum, ein Institut der Leibniz-Gemeinschaft, Berlin, Germany.
²² Institute of Microbiology, Infectious Diseases and Immunology Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Germany.
²³ Berlin Institute für Gesundheitsforschung, Medizinische System Biologie, Charité- Universitätsmedizin Berlin, Berlin, Germany.
²⁴ Institute of Immunology, Christian-Albrecht University of Kiel and Universitätsklinikum Schleswig-Holstein, Kiel, Germany.
²⁵ Department of Gastroenterology, Infectious Diseases and Rheumatology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; Max Delbrück Center für Molekulare Medizin, Charité-Universitätsmedizin Berlin, Berlin, Germany.
²⁶ Institute of Clinical Molecular Biology, Christian-Albrecht University of Kiel, Kiel, Germany.
²⁷ Deutsches Rheuma-Forschungszentrum, ein Institut der Leibniz-Gemeinschaft, Berlin, Germany; Department of Rheumatology and Clinical Immunology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.
²⁸ Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria; Department of Dermatology, Medical University of Vienna, Vienna, Austria.
²⁹ Department of Internal Medicine I, Gastroenterology, Hepatology, Endocrinology & Metabolism, Medical University of Innsbruck, Innsbruck, Austria. Electronic address: herbert.tilg@i-med.ac.at.
³⁰ Department of Internal Medicine I, Gastroenterology, Hepatology, Endocrinology & Metabolism, Medical University of Innsbruck, Innsbruck, Austria. Electronic address: timon-erik.adolph@i-med.ac.at.

PMID: 41295942
DOI: 10.1053/j.gastro.2025.08.040

Abstract

Background & aims: Quantification of the human S100A8/S100A9 tetrameric protein complex in stool, referred to as fecal calprotectin, is an extensively validated biomarker supporting the diagnosis and management of gastrointestinal diseases. Here, we studied the quaternary protein structures (termed configuration) of S100A8 and S100A9 and their biological function in inflammatory bowel diseases (IBD).

Methods: We dissected fecal S100A8 and S100A9 configurations in patients with IBD by size-exclusion chromatography coupled with tandem mass spectrometry and systematically defined human S100A8 and S100A9 homodimer functions compared with the calprotectin heterotetramer (CP) in the intestine of mice and in human epithelium and T cells. Moreover, we report a protein interaction network of fecal S100A8 and S100A9 in IBD.

Results: Stool from patients with active IBD contained abundant S100A8 and S100A9 dimers besides CP. Fecal S100A9 detection associated with clinical and endoscopic disease activity in IBD patients with low CP concentration. Oral exposure to human recombinant S100A8 and S100A9 homodimers, but not to CP, worsened intestinal inflammation in toxic and genetic mouse models. Functional profiling revealed that human S100A8 and S100A9 homodimers enhanced activation of cluster of differentiation 4⁺ and 8⁺ T cells, which promoted experimental colitis. In turn, genetic inactivation of S100a9 protected against experimental enteritis and colitis, and pharmacologic inhibition of S100A9 ameliorated chronic colitis.

Conclusions: Collectively, this study links the detection of fecal S100A9 dimers with clinical and endoscopic disease activity in IBD and identifies inflammatory actions of S100A8 and S100A9 homodimers in the intestine. Our findings pave the way for novel diagnostic and therapeutic approaches in patients with inflammatory diseases of the intestine.

Keywords: Calprotectin; Crohn's Disease; Inflammatory Bowel Diseases; Intestinal Inflammation; S100A8; S100A9; Ulcerative Colitis.