Bacteria-mucin interactions – Shaping intestinal epithelial responses in health and disease

Project Information

Bac2MUC

Grant agreement ID: 852452

DOI

10.3030/852452

Project closed

EC signature date 29 November 2019

Start date 1 March 2020

End date 28 February 2025

Funded under

• EXCELLENT SCIENCE - European Research Council (ERC)

Total cost

€ 1 500 000,00

EU contribution

€ 1 500 000,00

Coordinated by

UNIVERSITEIT UTRECHT
Netherlands

Periodic Reporting for period 4 - Bac2MUC (Bacteria-mucin interactions – Shaping intestinal epithelial responses in health and disease)

Reporting period: 2024-09-01 to 2025-02-28

Summary of the context and overall objectives of the project

Our gastrointestinal tract is covered with a mucus layer that protects the body from invasive pathogens but also facilitates symbiotic interactions with commensal bacteria. The mucus layer consists of different types of large mucin proteins that are decorated with complex sugar molecules. It is largely unknown how bacteria interact with these sugar-decorated mucin proteins and what are the functional consequences of these interactions for intestinal health and disease.

The aim of the Bac2MUC project was to identify pathogenic and commensal bacteria that interact with specific mucin glycoproteins called transmembrane mucins. These relatively unknown proteins are located on the apical surface and have diverse domains that suggest barrier and signaling functions. We hypothesized that transmembrane mucins play an important role in communication between intestinal bacteria and the host. The project also set out to determine the functions of mucins in preventing infection and maintaining intestinal health.

To investigate the functions of transmembrane mucins, we grew intestinal epithelial cultures in the lab with the correct mucin proteins that occur in the small and large intestine. We also used CRISPR gene-editing technology to engineer our cells to lack one mucin. Many intestinal bacteria cannot grow and thrive in the presence of oxygen, so most of our experiments had to be conducted in an anaerobic chamber. We performed adhesion and invasion experiments and visualized the bacteria-mucin interactions using fluorescence confocal microscopy.

We discovered that mucins play essential roles in maintaining intestinal health and that bacteria-mucin interactions are highly specific. Pathogens such as Salmonella have developed specific virulence factors to hijack mucins for invasion. The giant adhesin SiiE of Salmonella interacts with sialic acid-containing sugars on MUC1 and this interaction allows the bacteria to invade at the apical surface of the intestinal epithelium. We also discovered that the transmembrane mucin MUC13 is an important regulator of intestinal barrier function. The mucin contributes to opening of tight junctions which are the selective "gates" that regulate the uptake of nutrients and at the same time preventing bacterial invasion. Commensal bacteria such as Bifidobacteria colonize the mucus layer and cleave off mucin sugars for nutrition. We demonstrated that probiotic Bifidobacterium efficiently remove sugars from MUC13 and at the same time strengthens intestinal barrier functions, an example of a symbiotic relationship between commensals and host.

New knowledge about the molecular interactions of bacteria and mucins can benefit human health in several ways. For the pathogens, we can develop strategies to block their interaction so that they can no longer invade the body from the mucosal surface. For the commensals, it is important to know which bacteria can restore healthy intestinal barrier functions, for example for patients that suffer from leaky gut or inflammatory bowel disease. In the Strijbis group, we will continue to uncover specific bacteria-mucin interactions and their relevance for human health and disease.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

Publications in peer-reviewed journals

Probiotic Bifidobacterium bifidum strains desialylate MUC13 and increase intestinal epithelial barrier function.
Segui-Perez C, Huang LZX, Paganelli FL, Lievens E, Strijbis K.
Sci Rep. 2025 Mar 13;15(1):8778.

Development of a Caco-2-based intestinal mucosal model to study intestinal barrier properties and bacteria-mucus interactions.
Floor E, Su J, Chatterjee M, Kuipers ES, IJssennagger N, Heidari F, Giordano L, Wubbolts RW, Mihăilă SM, Stapels DAC, Vercoulen Y, Strijbis K.
Gut Microbes. 2025 Dec;17(1):2434685.

Reverse-engineering the anti-MUC1 antibody 139H2 by mass spectrometry-based de novo sequencing.
Peng W, Giesbers KC, Šiborová M, Beugelink JW, Pronker MF, Schulte D, Hilkens J, Janssen BJ, Strijbis K, Snijder J.
Life Sci Alliance. 2024 Mar 20;7(6):e202302366.

MUC13 negatively regulates tight junction proteins and intestinal epithelial barrier integrity via protein kinase C.
Segui-Perez C, Stapels DAC, Ma Z, Su J, Passchier E, Westendorp B, Wubbolts RW, Wu W, van Putten JPM, Strijbis K.
J Cell Sci. 2024 Mar 1;137(5):jcs261468.

Glycosylated extracellular mucin domains protect against SARS-CoV-2 infection at the respiratory surface.
Chatterjee M, Huang LZX, Mykytyn AZ, Wang C, Lamers MM, Westendorp B, Wubbolts RW, van Putten JPM, Bosch BJ, Haagmans BL, Strijbis K.
PLoS Pathog. 2023 Aug 10;19(8):e1011571.

O-Glycomic and Proteomic Signatures of Spontaneous and Butyrate-Stimulated Colorectal Cancer Cell Line Differentiation.
Madunić K, Luijkx YMCA, Mayboroda OA, Janssen GMC, van Veelen PA, Strijbis K, Wennekes T, Lageveen-Kammeijer GSM, Wuhrer M.
Mol Cell Proteomics. 2023 Mar;22(3):100501.

Detection of Bacterial α-l-Fucosidases with an Ortho-Quinone Methide-Based Probe and Mapping of the Probe-Protein Adducts.
Luijkx YMCA, Henselijn AJ, Bosman GP, Cramer DAT, Giesbers KCAP, van 't Veld EM, Boons GJ, Heck AJR, Reiding KR, Strijbis K, Wennekes T.
Molecules. 2022 Feb 28;27(5):1615.

Development of a 1,2-difluorofucoside activity-based probe for profiling GH29 fucosidases.
Luijkx YMCA, Jongkees S, Strijbis K, Wennekes T.
Org Biomol Chem. 2021 Apr 7;19(13):2968-2977.

The Transmembrane Mucin MUC1 Facilitates β1-Integrin-Mediated Bacterial Invasion.
Li X, Wubbolts RW, Bleumink-Pluym NMC, van Putten JPM, Strijbis K.
mBio. 2021 Apr 6;12(2):e03491-20.

Bacteroides fragilis fucosidases facilitate growth and invasion of Campylobacter jejuni in the presence of mucins.
Luijkx YMCA, Bleumink NMC, Jiang J, Overkleeft HS, Wösten MMSM, Strijbis K, Wennekes T.
Cell Microbiol. 2020 Dec;22(12):e13252.

Defensive Properties of Mucin Glycoproteins during Respiratory Infections-Relevance for SARS-CoV-2.
Chatterjee M, van Putten JPM, Strijbis K.
mBio. 2020 Nov 12;11(6):e02374-20.

Organization of international conferences

Organization of the International Mucin Conference
Location: Utrecht, the Netherlands
Dates: 27-07-2022 - 29-07-2022

Organization of the International Mucin Conference
Location: Gothenburg, Sweden
Dates: 17-06-2024 - 20-07-24

Selected press releases and outreach

- Article in Kijk magazine "Hoe is slijm in ons en andere zoogdieren ontstaan?" (27-08-2022)
- Online article and interview DDN "Mining mucus for drug inspiration" (14-03-2023)
- Presentation at primary school about "good and bad bacteria" (22-03-2024)
- Presentation general audience "Role of bacteria intestinal health" (14-04-2025)
- Bac2MUC Results in Brief article CORDIS website

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The corona pandemic outbreak hit the world in 2019. With our expertise in defensive functions of mucosal surfaces, we felt that we could contribute new knowlegde about this newly emerged virus and its pathogenesis. We collaborated with our colleagues from the Virology section and conducted a study about the role of glycosylated mucin proteins during SARS-CoV-2 infection at the respiratory surface. We also published a review paper about the potential barrier and receptor functions of mucins during bacterial and viral respiratory infection in 2020 and our experimental work was published in 2023. This project allowed us to also study the function of mucins during respiratory infections and broaden our insights into the general and specific functions of mucins and their glycans at different body sites.

Importance of intestinal bacteria-mucin interactions in health and disease