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Hancock SJ, Lo AW, Ve T, Day CJ, Tan L, Mendez AA, Phan MD, Nhu NTK, Peters KM, Richards AC, Fleming BA, Chang C, Ngu DHY, Forde BM, Haselhorst T, Goh KGK, Beatson SA, Jennings MP, Mulvey MA, Kobe B, Schembri MA. Ucl fimbriae regulation and glycan receptor specificity contribute to gut colonisation by extra-intestinal pathogenic Escherichia coli. PLoS Pathog 2022; 18:e1010582. [PMID: 35700218 PMCID: PMC9236248 DOI: 10.1371/journal.ppat.1010582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 06/27/2022] [Accepted: 05/09/2022] [Indexed: 11/25/2022] Open
Abstract
Extra-intestinal pathogenic Escherichia coli (ExPEC) belong to a critical priority group of antibiotic resistant pathogens. ExPEC establish gut reservoirs that seed infection of the urinary tract and bloodstream, but the mechanisms of gut colonisation remain to be properly understood. Ucl fimbriae are attachment organelles that facilitate ExPEC adherence. Here, we investigated cellular receptors for Ucl fimbriae and Ucl expression to define molecular mechanisms of Ucl-mediated ExPEC colonisation of the gut. We demonstrate differential expression of Ucl fimbriae in ExPEC sequence types associated with disseminated infection. Genome editing of strains from two common sequence types, F11 (ST127) and UTI89 (ST95), identified a single nucleotide polymorphism in the ucl promoter that changes fimbriae expression via activation by the global stress-response regulator OxyR, leading to altered gut colonisation. Structure-function analysis of the Ucl fimbriae tip-adhesin (UclD) identified high-affinity glycan receptor targets, with highest affinity for sialyllacto-N-fucopentose VI, a structure likely to be expressed on the gut epithelium. Comparison of the UclD adhesin to the homologous UcaD tip-adhesin from Proteus mirabilis revealed that although they possess a similar tertiary structure, apart from lacto-N-fucopentose VI that bound to both adhesins at low-micromolar affinity, they recognize different fucose- and glucose-containing oligosaccharides. Competitive surface plasmon resonance analysis together with co-structural investigation of UcaD in complex with monosaccharides revealed a broad-specificity glycan binding pocket shared between UcaD and UclD that could accommodate these interactions. Overall, our study describes a mechanism of adaptation that augments establishment of an ExPEC gut reservoir to seed disseminated infections, providing a pathway for the development of targeted anti-adhesion therapeutics. ExPEC infection of the urinary tract and bloodstream is frequently seeded from an intestinal reservoir, necessitating an understanding of the mechanisms that promote gut colonisation. Here we employed molecular and structural approaches to define the regulation and function of ExPEC Ucl fimbriae as a gut colonisation factor. We describe how mutations in the non-coding regulatory region of the ucl promoter cause increased Ucl fimbriae expression and promote enhanced gut colonisation via tuned induction by a global regulator that senses oxygen stress. We further define the glycan receptor targets of Ucl fimbriae and characterise the structural features of the Ucl adhesin that facilitate these interactions. These findings explain how ExPEC can adapt to survival in the gut to seed extra-intestinal infection.
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Affiliation(s)
- Steven J. Hancock
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
| | - Alvin W. Lo
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
| | - Thomas Ve
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
- Institute for Glycomics, Griffith University Gold Coast Campus, Gold Coast, Queensland, Australia
| | - Christopher J. Day
- Institute for Glycomics, Griffith University Gold Coast Campus, Gold Coast, Queensland, Australia
| | - Lendl Tan
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
| | - Alejandra A. Mendez
- Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Minh-Duy Phan
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
| | - Nguyen Thi Khanh Nhu
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
| | - Kate M. Peters
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
| | - Amanda C. Richards
- Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Brittany A. Fleming
- Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Chyden Chang
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
| | - Dalton H. Y. Ngu
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
| | - Brian M. Forde
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
| | - Thomas Haselhorst
- Institute for Glycomics, Griffith University Gold Coast Campus, Gold Coast, Queensland, Australia
| | - Kelvin G. K. Goh
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
| | - Scott A. Beatson
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
| | - Michael P. Jennings
- Institute for Glycomics, Griffith University Gold Coast Campus, Gold Coast, Queensland, Australia
| | - Matthew A. Mulvey
- Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Mark A. Schembri
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
- * E-mail:
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