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Bettin EB, Grassmann AA, Dellagostin OA, Gogarten JP, Caimano MJ. Leptospira interrogans encodes a canonical BamA and three novel noNterm Omp85 outer membrane protein paralogs. Sci Rep 2024; 14:19958. [PMID: 39198480 DOI: 10.1038/s41598-024-67772-6] [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: 04/14/2024] [Accepted: 07/15/2024] [Indexed: 09/01/2024] Open
Abstract
The Omp85 family of outer membrane proteins are ubiquitously distributed among diderm bacteria and play essential roles in outer membrane (OM) biogenesis. The majority of Omp85 orthologs are bipartite and consist of a conserved OM-embedded 16-stranded beta-barrel and variable periplasmic functional domains. Here, we demonstrate that Leptospira interrogans encodes four distinct Omp85 proteins. The presumptive leptospiral BamA, LIC11623, contains a noncanonical POTRA4 periplasmic domain that is conserved across Leptospiraceae. The remaining three leptospiral Omp85 proteins, LIC12252, LIC12254 and LIC12258, contain conserved beta-barrels but lack periplasmic domains. Two of the three 'noNterm' Omp85-like proteins were upregulated by leptospires in urine from infected mice compared to in vitro and/or following cultivation within rat peritoneal cavities. Mice infected with a L. interrogans lic11254 transposon mutant shed tenfold fewer leptospires in their urine compared to mice infected with the wild-type parent. Analyses of pathogenic and saprophytic Leptospira spp. identified five groups of noNterm Omp85 paralogs, including one pathogen- and two saprophyte-specific groups. Expanding our analysis beyond Leptospira spp., we identified additional noNterm Omp85 orthologs in bacteria isolated from diverse environments, suggesting a potential role for these previously unrecognized noNterm Omp85 proteins in physiological adaptation to harsh conditions.
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Affiliation(s)
- Everton B Bettin
- Department of Medicine, University of Connecticut Health, 263 Farmington Avenue, Farmington, CT, 06030-3715, USA
| | - André A Grassmann
- Department of Medicine, University of Connecticut Health, 263 Farmington Avenue, Farmington, CT, 06030-3715, USA
| | - Odir A Dellagostin
- Biotechnology Unit, Technological Development Center, Federal University of Pelotas, Pelotas, RS, Brazil
| | - Johann Peter Gogarten
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
| | - Melissa J Caimano
- Department of Medicine, University of Connecticut Health, 263 Farmington Avenue, Farmington, CT, 06030-3715, USA.
- Department of Pediatrics, University of Connecticut Health, Farmington, CT, USA.
- Department of Molecular Biology and Biophysics, University of Connecticut Health, Farmington, CT, USA.
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Cianciotto NP. The type II secretion system as an underappreciated and understudied mediator of interbacterial antagonism. Infect Immun 2024; 92:e0020724. [PMID: 38980047 PMCID: PMC11320942 DOI: 10.1128/iai.00207-24] [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] [Indexed: 07/10/2024] Open
Abstract
Interbacterial antagonism involves all major phyla, occurs across the full range of ecological niches, and has great significance for the environment, clinical arena, and agricultural and industrial sectors. Though the earliest insight into interbacterial antagonism traces back to the discovery of antibiotics, a paradigm shift happened when it was learned that protein secretion systems (e.g., types VI and IV secretion systems) deliver toxic "effectors" against competitors. However, a link between interbacterial antagonism and the Gram-negative type II secretion system (T2SS), which exists in many pathogens and environmental species, is not evident in prior reviews on bacterial competition or T2SS function. A current examination of the literature revealed four examples of a T2SS or one of its known substrates having a bactericidal activity against a Gram-positive target or another Gram-negative. When further studied, the T2SS effectors proved to be peptidases that target the peptidoglycan of the competitor. There are also reports of various bacteriolytic enzymes occurring in the culture supernatants of some other Gram-negative species, and a link between these bactericidal activities and T2SS is suggested. Thus, a T2SS can be a mediator of interbacterial antagonism, and it is possible that many T2SSs have antibacterial outputs. Yet, at present, the T2SS remains relatively understudied for its role in interbacterial competition. Arguably, there is a need to analyze the T2SSs of a broader range of species for their role in interbacterial antagonism. Such investigation offers, among other things, a possible pathway toward developing new antimicrobials for treating disease.
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Affiliation(s)
- Nicholas P. Cianciotto
- Department of Microbiology-Immunology, Northwestern University School of Medicine, Chicago, Illinois, USA
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de Oliveira NR, Santos FDS, Dos Santos VAC, Maia MAC, Oliveira TL, Dellagostin OA. Challenges and Strategies for Developing Recombinant Vaccines against Leptospirosis: Role of Expression Platforms and Adjuvants in Achieving Protective Efficacy. Pathogens 2023; 12:787. [PMID: 37375478 DOI: 10.3390/pathogens12060787] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 05/29/2023] [Accepted: 05/29/2023] [Indexed: 06/29/2023] Open
Abstract
The first leptospiral recombinant vaccine was developed in the late 1990s. Since then, progress in the fields of reverse vaccinology (RV) and structural vaccinology (SV) has significantly improved the identification of novel surface-exposed and conserved vaccine targets. However, developing recombinant vaccines for leptospirosis faces various challenges, including selecting the ideal expression platform or delivery system, assessing immunogenicity, selecting adjuvants, establishing vaccine formulation, demonstrating protective efficacy against lethal disease in homologous challenge, achieving full renal clearance using experimental models, and reproducibility of protective efficacy against heterologous challenge. In this review, we highlight the role of the expression/delivery system employed in studies based on the well-known LipL32 and leptospiral immunoglobulin-like (Lig) proteins, as well as the choice of adjuvants, as key factors to achieving the best vaccine performance in terms of protective efficacy against lethal infection and induction of sterile immunity.
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Affiliation(s)
- Natasha Rodrigues de Oliveira
- Núcleo de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas 96010-610, RS, Brazil
| | - Francisco Denis Souza Santos
- Núcleo de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas 96010-610, RS, Brazil
| | | | - Mara Andrade Colares Maia
- Núcleo de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas 96010-610, RS, Brazil
| | - Thaís Larré Oliveira
- Núcleo de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas 96010-610, RS, Brazil
| | - Odir Antônio Dellagostin
- Núcleo de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas 96010-610, RS, Brazil
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Vasconcelos L, Aburjaile F, Andrade L, Cancio AF, Seyffert N, Aguiar ERGR, Ristow P. Genomic insights into the c-di-GMP signaling and biofilm development in the saprophytic spirochete Leptospira biflexa. Arch Microbiol 2023; 205:180. [PMID: 37031284 DOI: 10.1007/s00203-023-03519-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 03/20/2023] [Accepted: 03/26/2023] [Indexed: 04/10/2023]
Abstract
C-di-GMP is a bacterial second messenger with central role in biofilm formation. Spirochete bacteria from Leptospira genus present a wide diversity, with species of medical importance and environmental species, named as saprophytic. Leptospira form biofilms in the rat's reservoir kidneys and in the environment. Here, we performed genomic analyses to identify enzymatic and effector c-di-GMP proteins in the saprophytic biofilm-forming species Leptospira biflexa serovar Patoc. We identified 40 proteins through local alignments. Amongst them, 16 proteins are potentially functional diguanylate cyclases, phosphodiesterases, or hybrid proteins. We also identified nine effectors, including PilZ proteins. Enrichment analyses suggested that c-di-GMP interacts with cAMP signaling system, CsrA system, and flagella assembly regulation during biofilm development of L. biflexa. Finally, we identified eight proteins in the pathogen Leptospira interrogans serovar Copenhageni that share high similarity with L. biflexa c-di-GMP-related proteins. This work revealed proteins related to c-di-GMP turnover and cellular response in Leptospira and their potential roles during biofilm development.
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Affiliation(s)
- Larissa Vasconcelos
- Institute of Biology, Federal University of Bahia, Salvador, Bahia, Brazil
- Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Flávia Aburjaile
- Preventive Veterinary Medicine Department, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Lara Andrade
- Institute of Biology, Federal University of Bahia, Salvador, Bahia, Brazil
| | | | - Núbia Seyffert
- Institute of Biology, Federal University of Bahia, Salvador, Bahia, Brazil
- Institute of Health Sciences, Federal University of Bahia, Salvador, Bahia, Brazil
| | - Eric R G R Aguiar
- Institute of Health Sciences, Federal University of Bahia, Salvador, Bahia, Brazil
- Department of Biological Science, Center of Biotechnology and Genetics, State University of Santa Cruz, Ilhéus, Bahia, Brazil
| | - Paula Ristow
- Institute of Biology, Federal University of Bahia, Salvador, Bahia, Brazil.
- National Institute of Science and Technology in Interdisciplinary and Transdisciplinary Studies in Ecology and Evolution (INCT IN-TREE), Federal University of Bahia, Salvador, Bahia, Brazil.
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Chaurasia R, Salovey A, Guo X, Desir G, Vinetz JM. Vaccination With Leptospira interrogans PF07598 Gene Family-Encoded Virulence Modifying Proteins Protects Mice From Severe Leptospirosis and Reduces Bacterial Load in the Liver and Kidney. Front Cell Infect Microbiol 2022; 12:926994. [PMID: 35837473 PMCID: PMC9274288 DOI: 10.3389/fcimb.2022.926994] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Accepted: 05/24/2022] [Indexed: 12/29/2022] Open
Abstract
The molecular and cellular pathogenesis of leptospirosis remains poorly understood. Based on comparative bacterial genomics data, we recently identified the hypothetical PF07598 gene family as encoding secreted exotoxins (VM proteins) that mediate cytotoxicity in vitro. To address whether VM proteins mediate in vivo leptospirosis pathogenesis, we tested the hypothesis that VM protein immunization of mice would protect against lethal challenge infection and reduce bacterial load in key target organs. C3H/HeJ mice were immunized with recombinant E. coli-produced, endotoxin-free, leptospiral VM proteins (derived from L. interrogans serovar Lai) in combination with the human-compatible adjuvant, glucopyranoside lipid A/squalene oil-in-water. Mice receiving full length recombinant VM proteins were protected from lethal challenge infection by L. interrogans serovar Canicola and had a 3-4 log10 reduction in bacterial load in the liver and kidney. These experiments show that immunization with recombinant VM proteins prevents leptospirosis clinical pathogenesis and leads to markedly reduced key target organ infection in this animal model. These data support the role of leptospiral VM proteins as virulence factors and suggest the possibility that a VM protein-based, serovar-independent, pan-leptospirosis vaccine may be feasible.
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Affiliation(s)
- Reetika Chaurasia
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
| | - Aryeh Salovey
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
| | - Xiaojia Guo
- Section of Nephrology, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
| | - Gary Desir
- Section of Nephrology, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
| | - Joseph M. Vinetz
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
- *Correspondence: Joseph M. Vinetz,
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Schuler EJA, Marconi RT. The Leptospiral General Secretory Protein D (GspD), a secretin, elicits complement-independent bactericidal antibody against diverse Leptospira species and serovars. Vaccine X 2021; 7:100089. [PMID: 33733085 PMCID: PMC7941034 DOI: 10.1016/j.jvacx.2021.100089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 02/18/2021] [Accepted: 02/20/2021] [Indexed: 11/21/2022] Open
Abstract
Leptospirosis, the most common zoonotic infection worldwide, is a multi-system disorder affecting the kidney, liver, and lungs. Infections can be asymptomatic, self-limiting or progress to multi-organ system failure and pulmonary hemorrhage. The incidence of canine and human leptospirosis is steadily increasing worldwide. At least sixty-four Leptospira species and several hundred lipopolysaccharide-based serovars have been defined. Preventive vaccines are available for use in veterinary medicine and limited use in humans in some countries. All commercially available vaccines are bacterin formulations that consist of a combination of laboratory cultivated strains of different lipopolysaccharide serotypes. The development of a broadly protective subunit vaccine would represent a significant step forward in efforts to combat leptospirosis in humans, livestock, and companion animals worldwide. Here we investigate the potential of General secretory protein D (GspD; LIC11570), a secretin, to serve as a possible antigen in a multi-valent vaccine formulation. GspD is conserved, expressed in vitro, antigenic during infection and elicits antibody with complement independent bactericidal activity. Importantly, antibody to GspD is bactericidal against diverse Leptospira species of the P1 subclade. Epitope mapping localized the bactericidal epitopes to the N-terminal N0 domain of GspD. The data within support further exploration of GspD as a candidate for inclusion in a next generation multi-protein subunit vaccine.
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Affiliation(s)
- EJA. Schuler
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, 1112 E Clay St., Richmond, VA 23298, USA
| | - RT. Marconi
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, 1112 E Clay St., Richmond, VA 23298, USA
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