Receptor-Targeted Next-Generation Probiotics Ameliorate Mammalian Colitis

¹ 1. Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, Indiana
² 2. Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, IN
³ 3. School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, 47907 USA
⁴ 4. Birck Nanotechnology Center, Purdue University, West Lafayette, IN, 47907 USA
⁵ 5. Department of Biological Science, Old Dominion University, Norfolk, Virginia
⁶ 6. Department of Animal Sciences, Purdue University, West Lafayette, Indiana
⁷ 7. Department of Comparative Pathology, Purdue University, West Lafayette, IN
⁸ 8. Biological System and Engineering, Lawrence Berkely National Laboratory, Berkely, CA
⁹ 9. Department of Veterinary Pathobiology, Texas A&M University, College Station, TX, USA
¹⁰ 10. Purdue University Interdisciplinary Life Sciences Program, Purdue University, West Lafayette, IN

Academic Editor: Antonio Bevilacqua

Published: 25 October 2024 by MDPI in The 5th International Electronic Conference on Foods session Food Microbiology

Abstract:

Introduction: a loss of intestinal barrier function, inflammation, and an elevated expression of epithelial heat shock protein 60 (Hsp60) are features of an inflamed bowel. Probiotics have been used to alleviate colitis-induced pathologies, but offer poor adhesion and adaptation to the diseased gut. We hypothesize that enhancing probiotic adhesion in the inflamed bowel may ameliorate such pathologies. Listeria adhesion protein (LAP; 94-kDa acetaldehyde alcohol dehydrogenase) aids Listeria attachment to the epithelial cells by interacting with the mammalian receptor Hsp60. Bioengineered Lactobacillus casei probiotics (BLPs) expressing LAP showed strong interaction with epithelial Hsp60, a high immunomodulatory response, and sustained epithelial barrier integrity.

Method: Dextran sodium sulfate (DSS)-treated mice were fed with BLP (1x10¹⁰ CFU/mL) for 10 days.

Results: DSS (2%, 7days)-fed mice treated with BLP showed a > 50% reduction in FITC-labeled 4 kDa dextran (FD4; epithelial permeability marker) translocation compared to the control groups. BLP-fed DSS-treated mice gained 3% body weight and conferred a 40% reduction in disease activity index (DAI) and inflammatory response compared to the control. BLP treatment restored fecal consistency to Type 3, 4 (Bristol scoring) within 9 days of feeding, while the controls failed. The colon showed visible damage (shortening), wall thickening, fragile tissue, and mucus accumulation in control mice, while the cecum and colon of BLP-fed mice appeared healthy. The microbiome data show a partial restoration of diversity and richness, primarily a distinct subpopulation fed with the BLPs. Myosin light chain kinase (MLCK, tight junction modulator) knock-out (KO) mice have increased resistance to DSS-induced colitis. Post-DSS treatment, BLP-fed MLCK mice improved weight gain, restored fecal consistency, and recuperated colonic health compared to the control groups, despite enhanced colitis symptoms.

Conclusions: Our BLPs offer promising results in alleviating mammalian gut inflammation and can be implemented as a food additive to improve gut health.

Keywords: Bioengineered probiotics, Listeria adhesion protein, Hsp60

View Poster