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Reinforcement of the intestinal mucosal barrier via mucus-penetrating PEGylated bacteria

Abstract

The breakdown of the gut’s mucosal barrier that prevents the infiltration of microorganisms, inflammatory cytokines and toxins into bodily tissues can lead to inflammatory bowel disease and to metabolic and autoimmune diseases. Here we show that the intestinal mucosal barrier can be reinforced via the oral administration of commensal bacteria coated with poly(ethylene glycol) (PEG) to facilitate their penetration into mucus. In mice with intestinal homoeostatic imbalance, mucus-penetrating PEGylated bacteria preferentially localized in mucus at the lower gastrointestinal tract, inhibited the invasion of pathogenic bacteria, maintained homoeostasis of the gut microbiota, stimulated the secretion of mucus and the expression of tight junctions, and prevented the mice from developing colitis and diabetes. Orally delivered PEGylated bacteria may help prevent and treat gastrointestinal disorders.

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Fig. 1: Illustration of the study approach.
Fig. 2: Characterization of the PEGylated bacteria.
Fig. 3: Penetration of PEGylated bacteria in reconstituted mucus.
Fig. 4: Penetration of PEGylated bacteria in gut mucus.
Fig. 5: Inhibition of pathogen invasion and regulation of the gut microbiota.
Fig. 6: Promotion of mucus and tight junction expressions.
Fig. 7: PEGylated bacteria-mediated remission of intestinal inflammatory damages.
Fig. 8: PEGylated bacteria-mediated reduction of insulin resistance.

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Data availability

The main data supporting the results in this study are available within the paper and its Supplementary Information. The 16S ribosomal RNA gene-sequencing data are available from NCBI (accession no. PRJNA1107831). The raw and analysed datasets generated during the study are available for research purposes from the corresponding author on reasonable request. Source data for the figures are provided with this paper.

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Acknowledgements

This work was financially supported by the National Key Research and Development Program of China (2021YFA0909400), the National Natural Science Foundation of China (32201144, 32301099, 22305152, 82204503), the Interdisciplinary Program of Shanghai Jiao Tong University (YG2022QN032), the Innovative Research Team of High-Level Local Universities in Shanghai (SHSMU-ZDCX20210900), the Youth Science and Technology Talents Yang Fan Plan of Shanghai (22YF1424200), the Explorer Program of the Science and Technology Commission of Shanghai Municipality (21TS1400400) and the Shanghai Municipal Education Commission–Gaofeng Clinical Medicine Grant Support (20181704).

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Contributions

J.L. supervised the project. J.L., Y.C., S.L. and L.W. conceived and designed the experiments. Y.C., Y.Z., H.C., Z.F., H.L., M.Z., L.W. and S.L. performed all experiments. All authors analysed and discussed the data. Y.C., L.W., S.L. and J.L. wrote the paper.

Corresponding author

Correspondence to Jinyao Liu.

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Nature Biomedical Engineering thanks Zhengwei Mao and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Extended data

Extended Data Fig. 1 Penetration of PEGylated bacteria in ileum mucus.

a,b, Representative IVIS images and corresponding fluorescence intensities of porcine ileum segments (a) and ileum mucus (b) after incubation with equivalent uncoated EcN, EP, or EPP expressing mCherry. c, Representative immunofluorescence images of mucus (green) in the ileum. Red and blue indicate EcN expressing mCherry and DAPI-labelled nuclei, respectively. White arrows represent EcN in ileum mucus. Scale bar, 100 μm. Data are means ± s.d. (n = 3). Statistical analysis was performed using one-way ANOVA. p values less than 0.05 are shown.

Source data

Extended Data Fig. 2 Penetration of PEGylated bacteria in cecum mucus.

a,b, Representative IVIS images and corresponding fluorescence intensities of porcine cecum segments (a) and cecum mucus (b) after incubation with equivalent uncoated EcN, EP, or EPP expressing mCherry. c, Representative immunofluorescence images of mucus (green) in the cecum. Red and blue indicate EcN expressing mCherry and DAPI-labelled nuclei, respectively. White arrows represent EcN in cecum mucus. Scale bar, 100 μm. Data are means ± s.d. (n = 3). Statistical analysis was performed using one-way ANOVA. p values less than 0.05 are shown.

Source data

Extended Data Fig. 3 Counts of PEGylated bacteria in the intestinal mucus layer.

Counts of EcN collected from mucus layer of each intestinal segment at 1 h after oral administration with EcN, EP, and EPP, respectively. Data are means ± s.d. (n = 3). Statistical analysis was performed using one-way ANOVA. p values less than 0.05 are shown.

Source data

Extended Data Fig. 4 Prevention of intestinal inflammatory damages.

a Experimental design of in vivo assessment using STm-infected mice. Mice were pretreated with PBS or equivalent EcN, EP, or EPP (n = 6). b Fluctuation of mouse body weight after treatment (n = 5 or 6). c,e, MPO staining images of the colon (c) and corresponding quantitative analysis of MPO+ cells (e). Navy blue arrows indicate MPO+ cells. Scale bar, 200 μm. d,f, H&E staining images of the colon (d) and corresponding quantitative analysis of crypt depth in the colon (f) (n = 5). Black and green arrows indicate inflammation and mucosal edema, respectively. Scale bar, 200 μm. g,h, Percentages of IL-4+CD4+ (g) and IFN-γ+CD4+ (h) T cells in the MLNs measured by flow cytometry (n = 5). Data are means ± s.d. Statistical analysis was performed using one-way ANOVA. p values less than 0.05 are shown.

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Supplementary information

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Chen, Y., Lin, S., Wang, L. et al. Reinforcement of the intestinal mucosal barrier via mucus-penetrating PEGylated bacteria. Nat. Biomed. Eng (2024). https://doi.org/10.1038/s41551-024-01224-4

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