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Shin HE, Pan C, Curran DM, Bateman TJ, Chong DHY, Ng D, Shah M, Moraes TF. Prevalence of Slam-dependent hemophilins in Gram-negative bacteria. J Bacteriol 2024; 206:e0002724. [PMID: 38814789 PMCID: PMC11332172 DOI: 10.1128/jb.00027-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 05/08/2024] [Indexed: 06/01/2024] Open
Abstract
Iron acquisition systems are crucial for pathogen growth and survival in iron-limiting host environments. To overcome nutritional immunity, bacterial pathogens evolved to use diverse mechanisms to acquire iron. Here, we examine a heme acquisition system that utilizes hemophores called hemophilins which are also referred to as HphAs in several Gram-negative bacteria. In this study, we report three new HphA structures from Stenotrophomonas maltophilia, Vibrio harveyi, and Haemophilus parainfluenzae. Structural determination of HphAs revealed an N-terminal clamp-like domain that binds heme and a C-terminal eight-stranded β-barrel domain that shares the same architecture as the Slam-dependent Neisserial surface lipoproteins. The genetic organization of HphAs consists of genes encoding a Slam homolog and a TonB-dependent receptor (TBDR). We investigated the Slam-HphA system in the native organism or the reconstituted system in Escherichia coli cells and found that the efficient secretion of HphA depends on Slam. The TBDR also played an important role in heme uptake and conferred specificity for its cognate HphA. Furthermore, bioinformatic analysis of HphA homologs revealed that HphAs are conserved in the alpha, beta, and gammaproteobacteria. Together, these results show that the Slam-dependent HphA-type hemophores are prevalent in Gram-negative bacteria and further expand the role of Slams in transporting soluble proteins. IMPORTANCE This paper describes the structure and function of a family of Slam (Type IX secretion System) secreted hemophores that bacteria use to uptake heme (iron) while establishing an infection. Using structure-based bioinformatics analysis to define the diversity and prevalence of this heme acquisition pathway, we discovered that a large portion of gammaproteobacterial harbors this system. As organisms, including Acinetobacter baumannii, utilize this system to facilitate survival during host invasion, the identification of this heme acquisition system in bacteria species is valuable information and may represent a target for antimicrobials.
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Affiliation(s)
- Hyejin Esther Shin
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Chuxi Pan
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - David M. Curran
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Thomas J. Bateman
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | | | - Dixon Ng
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Megha Shah
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Trevor F. Moraes
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
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Rodríguez-Arce I, Al-Jubair T, Euba B, Fernández-Calvet A, Gil-Campillo C, Martí S, Törnroth-Horsefield S, Riesbeck K, Garmendia J. Moonlighting of Haemophilus influenzae heme acquisition systems contributes to the host airway-pathogen interplay in a coordinated manner. Virulence 2019; 10:315-333. [PMID: 30973092 PMCID: PMC6550540 DOI: 10.1080/21505594.2019.1596506] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 02/18/2019] [Accepted: 03/12/2019] [Indexed: 01/30/2023] Open
Abstract
Nutrient iron sequestration is the most significant form of nutritional immunity and causes bacterial pathogens to evolve strategies of host iron scavenging. Cigarette smoking contains iron particulates altering lung and systemic iron homeostasis, which may enhance colonization in the lungs of patients suffering chronic obstructive pulmonary disease (COPD) by opportunistic pathogens such as nontypeable. NTHi is a heme auxotroph, and the NTHi genome contains multiple heme acquisition systems whose role in pulmonary infection requires a global understanding. In this study, we determined the relative contribution to NTHi airway infection of the four heme-acquisition systems HxuCBA, PE, SapABCDFZ, and HbpA-DppBCDF that are located at the bacterial outer membrane or the periplasm. Our computational studies provided plausible 3D models for HbpA, SapA, PE, and HxuA interactions with heme. Generation and characterization of single mutants in the hxuCBA, hpe, sapA, and hbpA genes provided evidence for participation in heme binding-storage and inter-bacterial donation. The hxuA, sapA, hbpA, and hpe genes showed differential expression and responded to heme. Moreover, HxuCBA, PE, SapABCDFZ, and HbpA-DppBCDF presented moonlighting properties related to resistance to antimicrobial peptides or glutathione import, together likely contributing to the NTHi-host airway interplay, as observed upon cultured airway epithelia and in vivo lung infection. The observed multi-functionality was shown to be system-specific, thus limiting redundancy. Together, we provide evidence for heme uptake systems as bacterial factors that act in a coordinated and multi-functional manner to subvert nutritional- and other sources of host innate immunity during NTHi airway infection.
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Affiliation(s)
| | - Tamim Al-Jubair
- Clinical Microbiology, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Begoña Euba
- Instituto de Agrobiotecnología, CSIC-Gobierno, Navarra, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | | | | | - Sara Martí
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain
- Departamento Microbiología, Hospital Universitari Bellvitge, University of Barcelona, IDIBELL, Barcelona, Spain
| | - Susanna Törnroth-Horsefield
- Department of Biochemistry and Structural Biology, Center for Molecular Protein Science, Lund University, Lund, Sweden
| | - Kristian Riesbeck
- Clinical Microbiology, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Junkal Garmendia
- Instituto de Agrobiotecnología, CSIC-Gobierno, Navarra, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain
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Choby JE, Skaar EP. Heme Synthesis and Acquisition in Bacterial Pathogens. J Mol Biol 2016; 428:3408-28. [PMID: 27019298 PMCID: PMC5125930 DOI: 10.1016/j.jmb.2016.03.018] [Citation(s) in RCA: 201] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/16/2016] [Accepted: 03/17/2016] [Indexed: 02/06/2023]
Abstract
Bacterial pathogens require the iron-containing cofactor heme to cause disease. Heme is essential to the function of hemoproteins, which are involved in energy generation by the electron transport chain, detoxification of host immune effectors, and other processes. During infection, bacterial pathogens must synthesize heme or acquire heme from the host; however, host heme is sequestered in high-affinity hemoproteins. Pathogens have evolved elaborate strategies to acquire heme from host sources, particularly hemoglobin, and both heme acquisition and synthesis are important for pathogenesis. Paradoxically, excess heme is toxic to bacteria and pathogens must rely on heme detoxification strategies. Heme is a key nutrient in the struggle for survival between host and pathogen, and its study has offered significant insight into the molecular mechanisms of bacterial pathogenesis.
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Affiliation(s)
- Jacob E Choby
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA; Tennessee Valley Healthcare System, U.S. Department of Veterans Affairs, Nashville, TN, USA.
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Duell BL, Su YC, Riesbeck K. Host-pathogen interactions of nontypeable Haemophilus influenzae: from commensal to pathogen. FEBS Lett 2016; 590:3840-3853. [PMID: 27508518 DOI: 10.1002/1873-3468.12351] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 08/01/2016] [Accepted: 08/05/2016] [Indexed: 11/09/2022]
Abstract
Nontypeable Haemophilus influenzae (NTHi) is a commensal microbe often isolated from the upper and lower respiratory tract. This bacterial species can cause sinusitis, acute otitis media in preschool children, exacerbations in patients suffering from chronic obstructive pulmonary disease, as well as conjunctivitis and bacteremia. Since the introduction of a vaccine against H. influenzae serotype b in the 1990s, the burden of H. influenzae-related infections has been increasingly dominated by NTHi. Understanding the ability of NTHi to cause infection is currently an expanding area of study. NTHi is able to exert differential binding to the host tissue through the use of a broad range of adhesins. NTHi survival in the host is multifaceted, that is, using virulence factors involved in complement resistance, biofilm, modified immunoglobulin responses, and, finally, formation and utilization of host proteins as a secondary strategy of increasing the adhesive ability.
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Affiliation(s)
- Benjamin Luke Duell
- Clinical Microbiology, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Yu-Ching Su
- Clinical Microbiology, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Kristian Riesbeck
- Clinical Microbiology, Department of Translational Medicine, Lund University, Malmö, Sweden
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Al-Jubair T, Mukherjee O, Oosterhuis S, Singh B, Su YC, Fleury C, Blom AM, Törnroth-Horsefield S, Riesbeck K. Haemophilus influenzae Type f Hijacks Vitronectin Using Protein H To Resist Host Innate Immunity and Adhere to Pulmonary Epithelial Cells. THE JOURNAL OF IMMUNOLOGY 2015; 195:5688-95. [PMID: 26538390 DOI: 10.4049/jimmunol.1501197] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 10/06/2015] [Indexed: 11/19/2022]
Abstract
The incidence of invasive Haemophilus influenzae type b (Hib) disease has significantly decreased since the introduction of an efficient vaccine against Hib. However, in contrast to Hib, infections caused by H. influenzae serotype f (Hif) are emerging. We recently did a whole genome sequencing of an invasive Hif isolate, and reported that Hif interacts with factor H by expressing protein H (PH). In this study, upon screening with various human complement regulators, we revealed that PH is also a receptor for vitronectin (Vn), an abundant plasma protein that regulates the terminal pathway of the human complement system in addition to being a component of the extracellular matrix. Bacterial Vn binding was significantly reduced when the lph gene encoding PH was deleted in an invasive Hif isolate. The dissociation constant (KD) of the interaction between recombinant PH and Vn was 2.2 μM, as revealed by Biolayer interferometry. We found that PH has different regions for simultaneous interaction with both Vn and factor H, and that it recognized the C-terminal part of Vn (aa 352-362). Importantly, PH-dependent Vn binding resulted in better survival of the wild-type Hif or PH-expressing Escherichia coli when exposed to human serum. Finally, we observed that PH mediated an increased bacterial adherence to alveolar epithelial cells in the presence of Vn. In conclusion, our study reveals that PH most likely plays an important role in Hif pathogenesis by increasing serum resistance and adhesion to the airways.
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Affiliation(s)
- Tamim Al-Jubair
- Clinical Microbiology, Department of Translational Medicine, Lund University, SE-205 02 Malmö, Sweden
| | - Oindrilla Mukherjee
- Clinical Microbiology, Department of Translational Medicine, Lund University, SE-205 02 Malmö, Sweden
| | - Sharon Oosterhuis
- Clinical Microbiology, Department of Translational Medicine, Lund University, SE-205 02 Malmö, Sweden
| | - Birendra Singh
- Clinical Microbiology, Department of Translational Medicine, Lund University, SE-205 02 Malmö, Sweden
| | - Yu-Ching Su
- Clinical Microbiology, Department of Translational Medicine, Lund University, SE-205 02 Malmö, Sweden
| | - Christophe Fleury
- Clinical Microbiology, Department of Translational Medicine, Lund University, SE-205 02 Malmö, Sweden
| | - Anna M Blom
- Protein Chemistry, Department of Translational Medicine, Lund University, SE-205 02 Malmö, Sweden; and
| | | | - Kristian Riesbeck
- Clinical Microbiology, Department of Translational Medicine, Lund University, SE-205 02 Malmö, Sweden;
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