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Saran A, Kim HM, Manning I, Hancock MA, Schmitz C, Madej M, Potempa J, Sola M, Trempe JF, Zhu Y, Davey ME, Zeytuni N. Unveiling the molecular mechanisms of the type IX secretion system's response regulator: Structural and functional insights. PNAS NEXUS 2024; 3:pgae316. [PMID: 39139265 PMCID: PMC11320123 DOI: 10.1093/pnasnexus/pgae316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 07/22/2024] [Indexed: 08/15/2024]
Abstract
The type IX secretion system (T9SS) is a nanomachinery utilized by bacterial pathogens to facilitate infection. The system is regulated by a signaling cascade serving as its activation switch. A pivotal member in this cascade, the response regulator protein PorX, represents a promising drug target to prevent the secretion of virulence factors. Here, we provide a comprehensive characterization of PorX both in vitro and in vivo. First, our structural studies revealed PorX harbors a unique enzymatic effector domain, which, surprisingly, shares structural similarities with the alkaline phosphatase superfamily, involved in nucleotide and lipid signaling pathways. Importantly, such pathways have not been associated with the T9SS until now. Enzymatic characterization of PorX's effector domain revealed a zinc-dependent phosphodiesterase activity, with active site dimensions suitable to accommodate a large substrate. Unlike typical response regulators that dimerize via their receiver domain upon phosphorylation, we found that zinc can also induce conformational changes and promote PorX's dimerization via an unexpected interface. These findings suggest that PorX can serve as a cellular zinc sensor, broadening our understanding of its regulatory mechanisms. Despite the strict conservation of PorX in T9SS-utilizing bacteria, we demonstrate that PorX is essential for virulence factors secretion in Porphyromonas gingivalis and affects metabolic enzymes secretion in the nonpathogenic Flavobacterium johnsoniae, but not for the secretion of gliding adhesins. Overall, this study advances our structural and functional understanding of PorX, highlighting its potential as a druggable target for intervention strategies aimed at disrupting the T9SS and mitigating virulence in pathogenic species.
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Affiliation(s)
- Anshu Saran
- Department of Anatomy and Cell Biology, McGill University, 3640 Rue University, Montreal, QC H3A 0C7, Canada
- Centre de Recherche en Biologie Structurale (CRBS), McGill University, 3649 Promenade Sir William Olser, Montreal, QC H3G 0B1, Canada
| | - Hey-Min Kim
- Department of Microbiology, The Forsyth Institute, 245 First St, Cambridge, MA 02142, USA
| | - Ireland Manning
- Department of Biological Sciences, Minnesota State University Mankato, 242 Trafton Science Center South, Mankato, MN 56001, USA
| | - Mark A Hancock
- Centre de Recherche en Biologie Structurale (CRBS), McGill University, 3649 Promenade Sir William Olser, Montreal, QC H3G 0B1, Canada
- Department of Pharmacology & Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Montreal, QC H3G 1Y6, Canada
| | - Claus Schmitz
- Department of Structural Biology, Molecular Biology Institute of Barcelona, Spanish Research Council, Barcelona Science Park, Barcelona E-08028, Spain
| | - Mariusz Madej
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Kraków PL-30-387, Poland
| | - Jan Potempa
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Kraków PL-30-387, Poland
- Department of Oral Immunology and Infectious Diseases, School of Dentistry, University of Louisville, 501 S Preston St, Louisville, KY 40202, USA
| | - Maria Sola
- Department of Structural Biology, Molecular Biology Institute of Barcelona, Spanish Research Council, Barcelona Science Park, Barcelona E-08028, Spain
| | - Jean-François Trempe
- Centre de Recherche en Biologie Structurale (CRBS), McGill University, 3649 Promenade Sir William Olser, Montreal, QC H3G 0B1, Canada
- Department of Pharmacology & Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Montreal, QC H3G 1Y6, Canada
| | - Yongtao Zhu
- Department of Biological Sciences, Minnesota State University Mankato, 242 Trafton Science Center South, Mankato, MN 56001, USA
- Department of Biological Sciences, Xi’an Jiaotong-Liverpool University, 111 Ren’ai Road, Suzhou Dushu Lake Science and Education Innovation District, Suzhou Industrial Park, Suzhou, Jiangsu 215123, China
| | - Mary Ellen Davey
- Department of Microbiology, The Forsyth Institute, 245 First St, Cambridge, MA 02142, USA
| | - Natalie Zeytuni
- Department of Anatomy and Cell Biology, McGill University, 3640 Rue University, Montreal, QC H3A 0C7, Canada
- Centre de Recherche en Biologie Structurale (CRBS), McGill University, 3649 Promenade Sir William Olser, Montreal, QC H3G 0B1, Canada
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Rothenberger CM, Yu M, Kim HM, Cheung YW, Chang YW, Davey ME. An outer membrane vesicle specific lipoprotein promotes Porphyromonas gingivalis aggregation on red blood cells. CURRENT RESEARCH IN MICROBIAL SCIENCES 2024; 7:100249. [PMID: 38974668 PMCID: PMC11225709 DOI: 10.1016/j.crmicr.2024.100249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/09/2024] Open
Abstract
Porphyromonas gingivalis uses a variety of mechanisms to actively interact with and promote the hydrolysis of red blood cells (RBCs) to obtain iron in the form of heme. In this study, we investigated the function of lipoprotein PG1881 which was previously shown to be up-regulated during subsurface growth and selectively enriched on outer membrane vesicles (OMVs). Our results show that wildtype strain W83 formed large aggregates encompassing RBCs whereas the PG1881 deletion mutant remained predominately as individual cells. Using a PG1881 antibody, immunofluorescence revealed that the wildtype strain's aggregation to RBCs involves an extracellular matrix enriched with PG1881. Our findings discover that RBCs elicit cell aggregation and matrix formation by P. gingivalis and that this process is promoted by an OMV-specific lipoprotein. We propose this strategy is advantageous for nutrient acquisition as well as dissemination from the oral cavity and survival of this periodontal pathogen.
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Affiliation(s)
- Christina M. Rothenberger
- Department of Microbiology, ADA Forsyth Institute, Cambridge, MA 02142, USA
- Department of Oral Microbiology, University of Florida College of Dentistry, University of Florida, Gainesville, FL, USA
| | - Manda Yu
- Department of Microbiology, ADA Forsyth Institute, Cambridge, MA 02142, USA
| | - Hey-Min Kim
- Department of Microbiology, ADA Forsyth Institute, Cambridge, MA 02142, USA
| | - Yee-Wai Cheung
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Yi-Wei Chang
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute of Structural Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Mary Ellen Davey
- Department of Microbiology, ADA Forsyth Institute, Cambridge, MA 02142, USA
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Melgar-Rodríguez S, Polanco A, Ríos-Muñoz J, García M, Sierra-Cristancho A, González-Osuna L, Díaz-Zúñiga J, Carvajal P, Vernal R, Bravo D. Differential Response of Human Dendritic Cells upon Stimulation with Encapsulated or Non-Encapsulated Isogenic Strains of Porphyromonas gingivalis. Int J Mol Sci 2024; 25:4510. [PMID: 38674095 PMCID: PMC11049913 DOI: 10.3390/ijms25084510] [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: 01/31/2024] [Revised: 04/12/2024] [Accepted: 04/17/2024] [Indexed: 04/28/2024] Open
Abstract
During periodontitis, the extracellular capsule of Porphyromonas gingivalis favors alveolar bone loss by inducing Th1 and Th17 patterns of lymphocyte response in the infected periodontium. Dendritic cells recognize bacterial antigens and present them to T lymphocytes, defining their activation and polarization. Thus, dendritic cells could be involved in the Th1 and Th17 response induced against the P. gingivalis capsule. Herein, monocyte-derived dendritic cells were obtained from healthy individuals and then stimulated with different encapsulated strains of P. gingivalis or two non-encapsulated isogenic mutants. Dendritic cell differentiation and maturation were analyzed by flow cytometry. The mRNA expression levels for distinct Th1-, Th17-, or T-regulatory-related cytokines and transcription factors, as well as TLR2 and TLR4, were assessed by qPCR. In addition, the production of IL-1β, IL-6, IL-23, and TNF-α was analyzed by ELISA. The encapsulated strains and non-encapsulated mutants of P. gingivalis induced dendritic cell maturation to a similar extent; however, the pattern of dendritic cell response was different. In particular, the encapsulated strains of P. gingivalis induced higher expression of IRF4 and NOTCH2 and production of IL-1β, IL-6, IL-23, and TNF-α compared with the non-encapsulated mutants, and thus, they showed an increased capacity to trigger Th1 and Th17-type responses in human dendritic cells.
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Affiliation(s)
- Samanta Melgar-Rodríguez
- Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Santiago 8380492, Chile; (S.M.-R.); (A.P.); (J.R.-M.); (M.G.); (A.S.-C.); (L.G.-O.); (J.D.-Z.); (P.C.)
- Department of Conservative Dentistry, Faculty of Dentistry, Universidad de Chile, Santiago 8380492, Chile
| | - Alan Polanco
- Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Santiago 8380492, Chile; (S.M.-R.); (A.P.); (J.R.-M.); (M.G.); (A.S.-C.); (L.G.-O.); (J.D.-Z.); (P.C.)
| | - Jearitza Ríos-Muñoz
- Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Santiago 8380492, Chile; (S.M.-R.); (A.P.); (J.R.-M.); (M.G.); (A.S.-C.); (L.G.-O.); (J.D.-Z.); (P.C.)
- Biomedical Research Center, Faculty of Medicine, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Michelle García
- Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Santiago 8380492, Chile; (S.M.-R.); (A.P.); (J.R.-M.); (M.G.); (A.S.-C.); (L.G.-O.); (J.D.-Z.); (P.C.)
| | - Alfredo Sierra-Cristancho
- Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Santiago 8380492, Chile; (S.M.-R.); (A.P.); (J.R.-M.); (M.G.); (A.S.-C.); (L.G.-O.); (J.D.-Z.); (P.C.)
- Faculty of Dentistry, Universidad Andrés Bello, Santiago 8370035, Chile
| | - Luis González-Osuna
- Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Santiago 8380492, Chile; (S.M.-R.); (A.P.); (J.R.-M.); (M.G.); (A.S.-C.); (L.G.-O.); (J.D.-Z.); (P.C.)
| | - Jaime Díaz-Zúñiga
- Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Santiago 8380492, Chile; (S.M.-R.); (A.P.); (J.R.-M.); (M.G.); (A.S.-C.); (L.G.-O.); (J.D.-Z.); (P.C.)
- Department of Conservative Dentistry, Faculty of Dentistry, Universidad de Chile, Santiago 8380492, Chile
| | - Paola Carvajal
- Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Santiago 8380492, Chile; (S.M.-R.); (A.P.); (J.R.-M.); (M.G.); (A.S.-C.); (L.G.-O.); (J.D.-Z.); (P.C.)
- Department of Conservative Dentistry, Faculty of Dentistry, Universidad de Chile, Santiago 8380492, Chile
| | - Rolando Vernal
- Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Santiago 8380492, Chile; (S.M.-R.); (A.P.); (J.R.-M.); (M.G.); (A.S.-C.); (L.G.-O.); (J.D.-Z.); (P.C.)
- Department of Conservative Dentistry, Faculty of Dentistry, Universidad de Chile, Santiago 8380492, Chile
| | - Denisse Bravo
- Laboratorio de Interacciones Microbianas, Faculty of Dentistry, Universidad Andrés Bello, Santiago 8370035, Chile
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Ghods S, Moradali MF, Duryea D, Walker AR, Davey ME. Growth of Porphyromonas gingivalis on human serum albumin triggers programmed cell death. J Oral Microbiol 2022; 15:2161182. [PMID: 36570975 PMCID: PMC9788703 DOI: 10.1080/20002297.2022.2161182] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Aims Gingival crevicular fluid (GCF) constitutes the primary growth substrate for Porphyromonas gingivalis in vivo. The goal of this work was to evaluate the growth of different strains of P. gingivalis on human serum albumin (HSA), a major constituent of GCF. Methods Growth of five different strains of P. gingivalis in the HSA medium was examined and, surprisingly, three of the strains underwent autolysis within 24 h. Comparative transcriptomic analysis was used to identify genes involved in autolysis. Results Two highly related reference strains (W50 and W83) differed dramatically in their survival when grown on HSA. Strain W83 grew fast and lysed within 24 h, while W50 survived for an additional 20 h. Differential gene expression analysis led us to a gene cluster containing enzymes involved in arginine metabolism and a gene predicted to be lytic murein transglycosylase, which are known to play a role in autolysis. Deletion of this gene (PG0139) resulted in a mutant that did not lyse, and complementation restored the HSA lysis phenotype, indicating that this enzyme plays a central role in the autolysis of P. gingivalis. Conclusions P. gingivalis undergoes autolysis when provided with HSA as a substrate for growth.
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Affiliation(s)
| | | | | | | | - Mary E. Davey
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA,CONTACT Mary E. Davey The Forsyth Institute, Cambridge, MA02142, USA
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Phillips PL, Wu XJ, Reyes L. Differential affinity chromatography reveals a link between Porphyromonas gingivalis-induced changes in vascular smooth muscle cell differentiation and the type 9 secretion system. Front Cell Infect Microbiol 2022; 12:983247. [PMID: 36483452 PMCID: PMC9722745 DOI: 10.3389/fcimb.2022.983247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 10/24/2022] [Indexed: 11/23/2022] Open
Abstract
Porphyromonas gingivalis is implicated in adverse pregnancy outcome. We previously demonstrated that intrauterine infection with various strains of P. gingivalis impairs the physiologic remodeling of the uterine spiral arteries (IRSA) during pregnancy, which underlies the major obstetrical syndromes. Women diagnosed with IRSA also have a greater risk for premature cardiovascular disease in later life. The dysregulated plasticity of vascular smooth muscle cells (VSMCs) is present in both IRSA and premature cardiovascular events. We hypothesized that VSMCs could serve as a bait to identify P. gingivalis proteins associated with dysregulated VSMC plasticity as seen in IRSA. We first confirmed that dams with P. gingivalis A7UF-induced IRSA also show perturbed aortic smooth muscle cell (AoSMC) plasticity along with the P. gingivalis colonization of the tissue. The in vitro infection of AoSMCs with IRSA-inducing strain A7UF also perturbed AoSMC plasticity that did not occur with infection by non-IRSA-inducing strain W83. Far-Western blotting with strain W83 and strain A7UF showed a differential binding pattern to the rat aorta and primary rat AoSMCs. The affinity chromatography/pull-down assay combined with mass spectrometry was used to identify P. gingivalis/AoSMC protein interactions specific to IRSA. Membrane proteins with a high binding affinity to AoSMCs were identified in the A7UF pull-down but not in the W83 pull-down, most of which were the outer membrane components of the Type 9 secretion system (T9SS) and T9SS cargo proteins. Additional T9SS cargo proteins were detected in greater abundance in the A7UF pull-down eluate compared to W83. None of the proteins enriched in the W83 eluate were T9SS components nor T9SS cargo proteins despite their presence in the prey preparations used in the pull-down assay. In summary, differential affinity chromatography established that the components of IRSA-inducing P. gingivalis T9SS as well as its cargo directly interact with AoSMCs, which may play a role in the infection-induced dysregulation of VSMC plasticity. The possibility that the T9SS is involved in the microbial manipulation of host cell events important for cell differentiation and tissue remodeling would constitute a new virulence function for this system.
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Affiliation(s)
- Priscilla L. Phillips
- Microbiology and Immunology, A.T. Still University of Health Sciences, Kirksville College of Osteopathic Medicine, Kirksville, MO, United States
| | - Xiao-jun Wu
- Department of Pathobiological Sciences, University of Wisconsin - Madison, School of Veterinary Medicine, Madison, WI, United States
| | - Leticia Reyes
- Department of Pathobiological Sciences, University of Wisconsin - Madison, School of Veterinary Medicine, Madison, WI, United States,*Correspondence: Leticia Reyes,
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Cortisol Promotes Surface Translocation of Porphyromonas gingivalis. Pathogens 2022; 11:pathogens11090982. [PMID: 36145414 PMCID: PMC9505793 DOI: 10.3390/pathogens11090982] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 08/20/2022] [Accepted: 08/24/2022] [Indexed: 11/17/2022] Open
Abstract
Studies are showing that the stress hormone cortisol can reach high levels in the gingival sulcus and induce shifts in the metatranscriptome of the oral microbiome. Interestingly, it has also been shown that cortisol can influence expression levels of Type IX Secretion System (T9SS) genes involved in gliding motility in bacteria belonging to the phylum Bacteroidota. The objective of this study was to determine if cortisol impacts gene expression and surface translocation of Porphyromonas gingivalis strain W50. To conduct these experiments, P. gingivalis was stabbed to the bottom of soft agar plates containing varying cortisol concentrations (0 μM, 0.13 μM, 1.3 μM, and 13 μM), and surface translocation on the subsurface was observed after 48 h of incubation. The results show that when grown with certain nutrients, i.e., in rich medium with the addition of sheep blood, lactate, or pyruvate, cortisol promotes migration of P. gingivalis in a concentration-dependent manner. To begin to examine the underlying mechanisms, quantitative PCR was used to evaluate differential expression of genes when P. gingivalis was exposed to cortisol. In particular, we focused on differential expression of T9SS-associated genes, including mfa5, since it was previously shown that Mfa5 is required for cell movement and cell-to-cell interactions. The data show that mfa5 is significantly up-regulated in the presence of cortisol. Moreover, an mfa5 deletion mutant showed less surface translocation compared to the wild-type P. gingivalis in the presence of cortisol, and the defects of the mfa5 deletion mutant were restored by complementation. Overall, cortisol can stimulate P. gingivalis surface translocation and this coincides with higher expression levels of T9SS-associated genes, which are known to be essential to gliding motility. Our findings support a high possibility that the stress hormone cortisol from the host can promote surface translocation and potentially virulence of P. gingivalis.
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