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Iida H, Nishikawa K, Sato T, Kawaguchi M, Miyazawa K, Hasegawa Y. Identification of Critical Amino Acid Residues of a Two-Component Sensor Protein for Signal Sensing in Porphyromonas gingivalis Fimbriation via Random Mutant Library Construction. Pathogens 2024; 13:309. [PMID: 38668264 PMCID: PMC11053733 DOI: 10.3390/pathogens13040309] [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: 03/15/2024] [Revised: 04/06/2024] [Accepted: 04/08/2024] [Indexed: 04/29/2024] Open
Abstract
Porphyromonas gingivalis (Pg) utilizes FimA fimbriae to colonize the gingival sulcus and evade the host immune system. The biogenesis of all FimA-related components is positively regulated by the FimS-FimR two-component system, making the FimS sensory protein an attractive target for preventing Pg infection. However, the specific environmental signal received by FimS remains unknown. We constructed random Pg mutant libraries to identify critical amino acid residues for signal sensing by FimS. Optimized error-prone polymerase chain reaction (PCR) was used to introduce a limited number of random mutations in the periplasmic-domain-coding sequence of fimS, and expression vectors carrying various mutants were generated by inverse PCR. More than 500 transformants were obtained from the fimS-knockout Pg strain using the Escherichia coli-Pg conjugal transfer system, whereas only ~100 transformants were obtained using electroporation. Four and six transformant strains showed increased and decreased fimA expression, respectively. Six strains had single amino acid substitutions in the periplasmic domain, indicating critical residues for signal sensing by FimS. This newly developed strategy should be generally applicable and contribute to molecular genetics studies of Pg, including the elucidation of structure-function relationships of proteins of interest.
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Affiliation(s)
- Haruka Iida
- Department of Orthodontics, School of Dentistry, Aichi Gakuin University, 2-11 Suemori-dori, Chikusa-ku, Nagoya 464-8651, Japan
| | - Kiyoshi Nishikawa
- Department of Microbiology, School of Dentistry, Aichi Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya 464-8650, Japan;
| | - Takuma Sato
- Department of Orthodontics, School of Dentistry, Aichi Gakuin University, 2-11 Suemori-dori, Chikusa-ku, Nagoya 464-8651, Japan
| | - Misuzu Kawaguchi
- Department of Orthodontics, School of Dentistry, Aichi Gakuin University, 2-11 Suemori-dori, Chikusa-ku, Nagoya 464-8651, Japan
| | - Ken Miyazawa
- Department of Orthodontics, School of Dentistry, Aichi Gakuin University, 2-11 Suemori-dori, Chikusa-ku, Nagoya 464-8651, Japan
| | - Yoshiaki Hasegawa
- Department of Microbiology, School of Dentistry, Aichi Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya 464-8650, Japan;
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The AtoC family response regulator upregulates an operon encoding putative outer membrane proteins sorted by type IX secretion system in Porphyromonas gingivalis. J Oral Biosci 2023; 65:80-87. [PMID: 36375735 DOI: 10.1016/j.job.2022.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 11/02/2022] [Accepted: 10/26/2022] [Indexed: 11/13/2022]
Abstract
OBJECTIVES Porphyromonas gingivalis, a keystone periodontopathogen, has multiple two-component systems that are thought to modulate virulence. In this study, we focused on PGN_0775 response regulator (RR), an AtoC homolog, and attempted to identify the target gene that it regulates in P. gingivalis. METHODS Comparative proteomic analyses comprising two-dimensional electrophoresis and peptide mass fingerprinting were applied to total protein samples from parent (WT) and atoC gene knockout (KO) strains to screen for affected protein spots. Fluctuations in the expression of corresponding genes were further confirmed using relative quantitative real-time polymerase chain reaction (RQPCR). RESULTS Five protein spots with fluctuating expression levels were identified in pgn_0775 KO strains along with their masses and physiological features, which contained two hypothetical proteins with higher expression levels in the WT than in the KO strains. RQPCR analysis confirmed that mRNA levels were consistently decreased in KO and recovered in pgn_0775-complemented KO strains. The two hypothetical proteins appeared to be the products of an operon that comprises four genes encoding three hypothetical but putative type IX secretion system sorting domain-containing proteins and an N-terminal region of the C25 cysteine peptidase. CONCLUSIONS The AtoC RR homolog in P. gingivalis upregulates the expression of the operon encoding potentially antigenic proteins retained on the cell surface; thus, it could be a promising target for P. gingivalis-specific antivirulence therapy.
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A Tale of Two Fimbriae: How Invasion of Dendritic Cells by Porphyromonas gingivalis Disrupts DC Maturation and Depolarizes the T-Cell-Mediated Immune Response. Pathogens 2022; 11:pathogens11030328. [PMID: 35335652 PMCID: PMC8954744 DOI: 10.3390/pathogens11030328] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/22/2022] [Accepted: 03/03/2022] [Indexed: 12/29/2022] Open
Abstract
Porphyromonas gingivalis (P. gingivalis) is a unique pathogen implicated in severe forms of periodontitis (PD), a disease that affects around 50% of the US population. P. gingivalis is equipped with a plethora of virulence factors that it uses to exploit its environment and survive. These include distinct fimbrial adhesins that enable it to bind to other microbes, colonize inflamed tissues, acquire nutrients, and invade cells of the stroma and immune system. Most notable for this review is its ability to invade dendritic cells (DCs), which bridge the innate and adaptive immune systems. This invasion process is tightly linked to the bridging functions of resultant DCs, in that it can disable (or stimulate) the maturation function of DCs and cytokines that are secreted. Maturation molecules (e.g., MHCII, CD80/CD86, CD40) and inflammatory cytokines (e.g., IL-1b, TNFa, IL-6) are essential signals for antigen presentation and for proliferation of effector T-cells such as Th17 cells. In this regard, the ability of P. gingivalis to coordinately regulate its expression of major (fimA) and minor (mfa-1) fimbriae under different environmental influences becomes highly relevant. This review will, therefore, focus on the immunoregulatory role of P. gingivalis fimbriae in the invasion of DCs, intracellular signaling, and functional outcomes such as alveolar bone loss and immune senescence.
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Ma Q, Zhang Q, Chen Y, Yu S, Huang J, Liu Y, Gong T, Li Y, Zou J. Post-translational Modifications in Oral Bacteria and Their Functional Impact. Front Microbiol 2021; 12:784923. [PMID: 34925293 PMCID: PMC8674579 DOI: 10.3389/fmicb.2021.784923] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 11/02/2021] [Indexed: 02/05/2023] Open
Abstract
Oral bacteria colonize the oral cavity, surrounding complex and variable environments. Post-translational modifications (PTMs) are an efficient biochemical mechanism across all domains of life. Oral bacteria could depend on PTMs to quickly regulate their metabolic processes in the face of external stimuli. In recent years, thanks to advances in enrichment strategies, the number and variety of PTMs that have been identified and characterized in oral bacteria have increased. PTMs, covalently modified by diverse enzymes, occur in amino acid residues of the target substrate, altering the functions of proteins involved in different biological processes. For example, Ptk1 reciprocally phosphorylates Php1 on tyrosine residues 159 and 161, required for Porphyromonas gingivalis EPS production and community development with the antecedent oral biofilm constituent Streptococcus gordonii, and in turn Php1 dephosphorylates Ptk1 and rapidly causes the conversion of Ptk1 to a state of low tyrosine phosphorylation. Protein acetylation is also widespread in oral bacteria. In the acetylome of Streptococcus mutans, 973 acetylation sites were identified in 445 proteins, accounting for 22.7% of overall proteins involving virulence factors and pathogenic processes. Other PTMs in oral bacteria include serine or threonine glycosylation in Cnm involving intracerebral hemorrhage, arginine citrullination in peptidylarginine deiminases (PADs), leading to inflammation, lysine succinylation in P. gingivalis virulence factors (gingipains, fimbriae, RagB, and PorR), and cysteine glutathionylation in thioredoxin-like protein (Tlp) in response to oxidative stress in S. mutans. Here we review oral bacterial PTMs, focusing on acetylation, phosphorylation, glycosylation, citrullination, succinylation, and glutathionylation, and corresponding modifying enzymes. We describe different PTMs in association with some examples, discussing their potential role and function in oral bacteria physiological processes and regulatory networks. Identification and characterization of PTMs not only contribute to understanding their role in oral bacterial virulence, adaption, and resistance but will open new avenues to treat oral infectious diseases.
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Affiliation(s)
- Qizhao Ma
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Qiong Zhang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yang Chen
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Shuxing Yu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jun Huang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yaqi Liu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Tao Gong
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yuqing Li
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jing Zou
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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5
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Jung CJ, Hsu CC, Chen JW, Cheng HW, Yuan CT, Kuo YM, Hsu RB, Chia JS. PspC domain-containing protein (PCP) determines Streptococcus mutans biofilm formation through bacterial extracellular DNA release and platelet adhesion in experimental endocarditis. PLoS Pathog 2021; 17:e1009289. [PMID: 33577624 PMCID: PMC7906467 DOI: 10.1371/journal.ppat.1009289] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 02/25/2021] [Accepted: 01/07/2021] [Indexed: 11/19/2022] Open
Abstract
Bacterial extracellular DNA (eDNA) and activated platelets have been found to contribute to biofilm formation by Streptococcus mutans on injured heart valves to induce infective endocarditis (IE), yet the bacterial component directly responsible for biofilm formation or platelet adhesion remains unclear. Using in vivo survival assays coupled with microarray analysis, the present study identified a LiaR-regulated PspC domain-containing protein (PCP) in S. mutans that mediates bacterial biofilm formation in vivo. Reverse transcriptase- and chromatin immunoprecipitation-polymerase chain reaction assays confirmed the regulation of pcp by LiaR, while PCP is well-preserved among streptococcal pathogens. Deficiency of pcp reduced in vitro and in vivo biofilm formation and released the eDNA inside bacteria floe along with reduced bacterial platelet adhesion capacity in a fibrinogen-dependent manner. Therefore, LiaR-regulated PCP alone could determine release of bacterial eDNA and binding to platelets, thus contributing to biofilm formation in S. mutans-induced IE.
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Affiliation(s)
- Chiau-Jing Jung
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Chih-Chieh Hsu
- Graduate Institute of Oral Biology, School of Dentistry, National Taiwan University, Taipei, Taiwan
| | - Jeng-Wei Chen
- Division of Cardiovascular Surgery, Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Hung-Wei Cheng
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chang-Tsu Yuan
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
- Department of Pathology, National Taiwan University Cancer Center, Taipei, Taiwan
- Department of Pathology, National Taiwan University Hospital, Taipei, Taiwan
| | - Yu-Min Kuo
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ron-Bin Hsu
- Division of Cardiovascular Surgery, Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan
| | - Jean-San Chia
- Graduate Institute of Oral Biology, School of Dentistry, National Taiwan University, Taipei, Taiwan
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
- Graduate Institute of Immunology, College of Medicine, National Taiwan University, Taipei, Taiwan
- * E-mail:
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6
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Yao K, Cai JY, Zhao L, Wu YF, Zhao ZH, Shen DN. Research progress on two-component signal transduction systems in Porphyromonas gingivalis. HUA XI KOU QIANG YI XUE ZA ZHI = HUAXI KOUQIANG YIXUE ZAZHI = WEST CHINA JOURNAL OF STOMATOLOGY 2021; 39:88-93. [PMID: 33723942 DOI: 10.7518/hxkq.2021.01.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Porphyromonas gingivalis (P. gingivalis), a Gram-negative oral anaerobe, is considered to be a major pathogenic agent involved in the onset and progression of chronic periodontitis. P. gingivalis must be able to perceive and respond to the complicated changes in host to survive the environmental challenges, in which the two-component signal transduction systems (TCSs) play critical roles by connecting input signals to cellular physiological output. Canonical TCS consists of a sensor histidine kinase and a cognate response regulator that functions via a phosphorylation cascade. In this review, the roles of TCSs in P. gingivalis were demonstrated by illustrating the target genes and modulation modes, which may help elucidate the underlying mechanisms in future studies.
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Affiliation(s)
- Ke Yao
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Jing-Yi Cai
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Lei Zhao
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Ya-Fei Wu
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Zhi-He Zhao
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Dao-Nan Shen
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
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7
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Yu S, Fan X, Zheng S, Lin L, Liu J, Pan Y, Li C. The sialidase inhibitor, DANA, reduces Porphyromonas gingivalis pathogenicity and exerts anti-inflammatory effects: An in vitro and in vivo experiment. J Periodontol 2020; 92:286-297. [PMID: 32609876 DOI: 10.1002/jper.19-0688] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 04/03/2020] [Accepted: 04/16/2020] [Indexed: 12/21/2022]
Abstract
BACKGROUND Sialidase has an important role in the pathogenesis of periodontitis and Porphyromonas gingivalis is a sialidase-producing organism implicated in periodontitis development. The aim of this study was to evaluate the anti-virulence and anti-inflammatory properties of the sialidase inhibitor, 2-deoxy-2,3-didehydro-N-acetylneuraminic acid (DANA), in vitro and in vivo. METHODS The effects of DANA on P. gingivalis sialidase and cell viability were determined, and the effects of DANA on P. gingivalis virulence were evaluated by assessment of growth curves, cell morphology, biofilm formation, fimbriae gene expression, and gingipains and lipopolysaccharide (LPS) activity. Anti-inflammatory effects of DANA on LPS-induced macrophages were assessed by measurement of tumor necrosis factor-alpha (TNF-α), interleukin (IL-1β), inducible nitric oxide synthase (iNOS) secretions. The effect of DANA on P. gingivalis-induced periodontitis in rats was analyzed by radiography, stereoscopic microscopy, histopathology, and immunohistochemistry. RESULTS Sialidase inhibition rate of 1mM DANA was 72.01%. Compared with untreated controls, treatment with DANA inhibited P. gingivalis growth and biofilm formation, and significantly decreased expression of the fimA, fimR, and fimS genes, as well as gingipains activity. DANA did not influence macrophage viability, but significantly inhibited TNF-α, IL-1β, and iNOS production in LPS-stimulated macrophages. In the periodontitis rat model, DANA prevented alveolar bone absorption and inhibited TNF-α and IL-1β production. CONCLUSION DANA can reduce the growth, the biofilm formation and the virulence of P. gingivalis and exhibits anti-inflammatory effects, as well as effects against rat periodontitis, suggesting that DANA should be considered for development as a new adjunctive treatment for periodontitis.
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Affiliation(s)
- Shiwen Yu
- School and Hospital of Stomatology, China Medical University, Shenyang, Liaoning, China
| | - Xiaomiao Fan
- School and Hospital of Stomatology, China Medical University, Shenyang, Liaoning, China
| | - Shaowen Zheng
- School and Hospital of Stomatology, China Medical University, Shenyang, Liaoning, China.,Liaoning Provincial Key Laboratory of Oral Disease, Shenyang, Liaoning, China
| | - Li Lin
- School and Hospital of Stomatology, China Medical University, Shenyang, Liaoning, China
| | - Jingbo Liu
- School and Hospital of Stomatology, China Medical University, Shenyang, Liaoning, China.,Liaoning Provincial Key Laboratory of Oral Disease, Shenyang, Liaoning, China
| | - Yaping Pan
- School and Hospital of Stomatology, China Medical University, Shenyang, Liaoning, China
| | - Chen Li
- School and Hospital of Stomatology, China Medical University, Shenyang, Liaoning, China
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Fujiwara-Takahashi K, Watanabe T, Shimogishi M, Shibasaki M, Umeda M, Izumi Y, Nakagawa I. Phylogenetic diversity in fim and mfa gene clusters between Porphyromonas gingivalis and Porphyromonas gulae, as a potential cause of host specificity. J Oral Microbiol 2020; 12:1775333. [PMID: 32944148 PMCID: PMC7482747 DOI: 10.1080/20002297.2020.1775333] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Background Periodontopathic bacteria Porphyromonas gingivalis in humans and Porphyromonas gulae in animals are phylogenetically close and commonly have FimA and Mfa1 fimbriae. However, little is known about how fimA and mfa1 are phylogenetically different between P. gingivalis and P. gulae. Here, we examined phylogenetic diversity in their fim and mfa gene clusters. Methods Twenty P. gulae strains were isolated from the periodontal pocket of 20 dogs. For their genomic information, along with 64 P. gingivalis and 11 P. gulae genomes, phylogenetic relationship between the genotypes of fimA and mfa1 was examined. Variability of amino acid sequences was examined in the three-dimensional structure of FimA. The distance between strains was calculated for fim and mfa genes. Results Some fimA genotypes in P. gulae were close to particular types in P. gingivalis. Two types of mfa1 were classified as 70-kDa and 53-kDa protein-coding mfa1. The variable amino acid positions were primarily at the outer part of FimA. The genes encoding the structural proteins and the main component were similarly distant from the reference strain in P. gingivalis, but not in P. gulae. Conclusions The differences in the gene clusters between P. gingivalis and P. gulae may result in their host specificity.
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Affiliation(s)
- Kaori Fujiwara-Takahashi
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.,Both the authors have equally contributed to this article.,Present address: Veterinary Teaching Hospital, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima-shi, Kagoshima, Japan
| | - Takayasu Watanabe
- Department of Chemistry, Nihon University School of Dentistry, Tokyo, Japan.,Both the authors have equally contributed to this article
| | - Masahiro Shimogishi
- Department of Oral Implantology and Regenerative Dental Medicine, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Masaki Shibasaki
- Department of Oral Implantology and Regenerative Dental Medicine, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Makoto Umeda
- Department of Periodontology, Graduate School of Dentistry, Osaka Dental University, Osaka, Japan
| | - Yuichi Izumi
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.,Oral Care Perio Center, Southern TOHOKU General Hospital, Southern TOHOKU Research Institute for Neuroscience, Fukushima, Japan
| | - Ichiro Nakagawa
- Department of Microbiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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Lei L, Zhang B, Mao M, Chen H, Wu S, Deng Y, Yang Y, Zhou H, Hu T. Carbohydrate Metabolism Regulated by Antisense vicR RNA in Cariogenicity. J Dent Res 2019; 99:204-213. [PMID: 31821772 DOI: 10.1177/0022034519890570] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Streptococcus mutans is a major cariogenic pathogen that resides in multispecies oral microbial biofilms. The VicRK 2-component system is crucial for bacterial adaptation, virulence, and biofilm organization and contains a global and vital response regulator, VicR. Notably, we identified an antisense vicR RNA (AS vicR) associated with an adjacent RNase III–encoding ( rnc) gene that was relevant to microRNA-size small RNAs (msRNAs). Here, we report that ASvicR overexpression significantly impeded bacterial growth, biofilm exopolysaccharide synthesis, and cariogenicity in vivo. Transcriptome analysis revealed that the AS vicR RNA mainly regulated carbohydrate metabolism. In particular, overproducing AS vicR demonstrated a reduction in galactose and glucose metabolism by monosaccharide composition analysis. The results of high-performance gel permeation chromatography revealed that the water-insoluble glucans isolated from AS vicR presented much lower molecular weights. Furthermore, direct evidence showed that total RNAs were disrupted by rnc-encoded RNase III. With the coexpression of T4 RNA ligase, putative msRNA1657, which is an rnc-related messenger RNA, was verified to bind to the 5′-UTR regions of the vicR gene. Furthermore, AS vicR regulation revealed a sponge regulatory-mediated network for msRNA associated with adjacent RNase III–encoding genes. There was an increase in AS vicR transcript levels in clinical S. mutans strains from caries-free children, while the expression of AS vicR was decreased in early childhood caries patients; this outcome may be explored as a potential strategy contributing to the management of dental caries. Taken together, our findings suggest an important role of AS vicR-mediated sponge regulation in S. mutans, indicating the characterization of lactose metabolism by a vital response regulator in cariogenicity. These findings have a number of implications and have reshaped our understanding of bacterial gene regulation from its transcriptional conception to the key roles of regulatory RNAs.
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Affiliation(s)
- L. Lei
- State Key Laboratory of Oral Diseases, Department of Preventive Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - B. Zhang
- State Key Laboratory of Oral Diseases, Department of Preventive Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - M. Mao
- State Key Laboratory of Oral Diseases, Department of Preventive Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
- Department of Endodontics, College of Stomatology, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - H. Chen
- State Key Laboratory of Oral Diseases, Department of Preventive Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - S. Wu
- West China School of Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Y. Deng
- State Key Laboratory of Oral Diseases, Department of Preventive Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Y. Yang
- State Key Laboratory of Oral Diseases, Department of Preventive Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - H. Zhou
- Department of Oral Medicine, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - T. Hu
- State Key Laboratory of Oral Diseases, Department of Preventive Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
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Miller DP, Lamont RJ. Signaling Systems in Oral Bacteria. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1197:27-43. [PMID: 31732932 DOI: 10.1007/978-3-030-28524-1_3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The supra- and subgingival plaque biofilm communities of plaque are composed of hundreds of different microbes. These communities are spatially and temporally structured, largely due to cell-cell communications that coordinate synergistic interactions, and intracellular signaling systems to sense changes in the surrounding environment. Homeostasis is maintained through metabolic communication, mutualistic cross-feeding, and cross-respiration. These nutritional symbioses can reciprocally influence the local microenvironments by altering the pH and by detoxifying oxidative compounds. Signal transduction mechanisms include two-component systems, tyrosine phosphorelays, quorum sensing systems, and cyclic nucleotide secondary messengers. Signaling converges on transcriptional programs and can result in synergistic or antagonistic interbacterial interactions that sculpt community development. The sum of all these interactions can be a well-organized polymicrobial community that remains in homeostasis with the host, or a dysbiotic community that provokes pathogenic responses in the host.
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Affiliation(s)
- Daniel P Miller
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry, Louisville, KY, USA
| | - Richard J Lamont
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry, Louisville, KY, USA.
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11
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Regulation of CATSPER1 expression by the testis-determining gene SRY. PLoS One 2018; 13:e0205744. [PMID: 30379860 PMCID: PMC6209213 DOI: 10.1371/journal.pone.0205744] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 09/03/2018] [Indexed: 11/19/2022] Open
Abstract
CATSPER1 gene encodes a pore-forming and pH-sensing subunit of the CatSper Ca2+- permeable channel, a protein in the flagellum essential for sperm hyperactivation. Previous studies have shown that the murine Catsper1 gene promoter is regulated by different Sox proteins. Likewise, it is acknowledged that the human CATSPER1 gene promoter sequence is enriched in potential interaction sites for the sex-determining region Y gene (SRY), which suggest a novel regulatory transcriptional mechanism for CatSper1 channel expression. Therefore, in this work, we sought to determine whether the human CATSPER1 gene expression is regulated by the SRY transcription factor. To this end, a series of deletions and mutations were introduced in the wild- type CATSPER1 gene promoter to eliminate the SRY sites, and the different constructs were tested for their ability to activate transcription in human embryonic kidney and murine spermatogonial germ cell lines (HEK-293 and GC1-spg, respectively) using luciferase assays. In addition, by using a strategy that combines electrophoretic mobility shift assays (EMSA) and chromatin immunoprecipitation (ChIP) we investigated whether the CATSPER1 gene expression is regulated by the SRY transcription factor both in vitro and in vivo. Our results show that the transcriptional factor SRY specifically binds to different sites in the promoter sequence and has the ability to control CATSPER1 gene transcription.
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12
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Lei L, Stipp RN, Chen T, Wu SZ, Hu T, Duncan MJ. Activity of Streptococcus mutans VicR Is Modulated by Antisense RNA. J Dent Res 2018; 97:1477-1484. [PMID: 29969955 DOI: 10.1177/0022034518781765] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The VicRK 2-component system of Streptococcus mutans regulates genes associated with cell wall biogenesis and biofilm formation. A putative RNase III-encoding gene ( rnc) is located downstream from the vicRKX operon. The goals of this study were to investigate the potential role of VicR in the regulation of adjacent downstream genes and evaluate transcription levels of vicR during planktonic and biofilm growth. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to investigate whether vicRKX and adjacent downstream genes were cotranscribed. Binding of purified recombinant VicR protein to promoter regions of vicR, rnc, and syfA genes was confirmed by electrophoretic mobility shift assay and by chromatin immunoprecipitation analyses. VicR antisense (AS vicR) RNA was detected by Northern blotting and qRT-PCR assays. AS vicR overexpression mutants were constructed, and the biofilm biomass was determined by crystal violet microtiter assay. Adjacent downstream genes rnc, smc, syfA, smu.1511, and syfB were cotranscribed with vicRKX. The predicted promoter regions of vicR, rnc, and syfA genes were directly regulated by VicR. An AS vicR RNA transcript was detected upstream of the rnc gene. Expression of the AS vicR RNA transcript was elevated in planktonic cultures and repressed during biofilm growth. In addition, Western blot data showed that expression of the VicR protein decreased by 35% in planktonic as compared with biofilm cultures. Furthermore, we show that overexpression of AS vicR led to a reduction in biofilm formation. The downstream genes rnc, smc, syfA, smu.1511, and syfB are cotranscribed with vicRKX. VicR is autophosphorylated, and rnc and syfA are directly regulated by VicR. Expression of VicR protein correlated inversely with different levels of AS vicR RNA transcript and growth conditions. The biofilm biomass decreased in the AS vicR overexpression mutant. These data suggest a role for the AS vicR RNA transcript in posttranscriptional regulation of VicR protein production in S. mutans.
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Affiliation(s)
- L Lei
- 1 State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Preventive Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,2 The Forsyth Institute, Cambridge, MA, USA
| | - R N Stipp
- 2 The Forsyth Institute, Cambridge, MA, USA.,3 Department of Oral Diagnosis, Piracicaba Dental School, University of Campinas, Campinas, Brazil
| | - T Chen
- 2 The Forsyth Institute, Cambridge, MA, USA
| | - S Z Wu
- 4 West China Hospital, West China Medical School, Sichuan University, Chengdu, China
| | - T Hu
- 1 State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Preventive Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - M J Duncan
- 2 The Forsyth Institute, Cambridge, MA, USA
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13
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Li Y, Krishnan K, Duncan MJ. Post-translational regulation of a Porphyromonas gingivalis regulator. J Oral Microbiol 2018; 10:1487743. [PMID: 29988788 PMCID: PMC6032018 DOI: 10.1080/20002297.2018.1487743] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 05/29/2018] [Indexed: 02/05/2023] Open
Abstract
Background: Bacteria use two-component signal transduction systems (among others) to perceive and respond to environmental changes. Within the genus Porphyromonas, we observed degeneration of these systems, as exemplified by the loss of RprX, the sensor kinase partner of the RprY. Objective: The purpose of this study was to investigate modulation of RprY function by acetylation. Design: The transcriptional activity of the rprY-pat genes were measured by RT-PCR and 5ʹ-RACE. The acetylation of RprY were detected by western blotting. Electromobility shift and in vitro ChIP assays were used to measure the DNA binding activity of RprY. The expression of RprY target genes was measured by qRT-PCR. Effects of acetylation on phosphorylation of RprY were measured by Phos-tag gels. Results: The rprY gene is cotranscribed with pat. RprY is acetylated in vivo, and autoacetylated in vitro in a reaction that is enhanced by Pat; the CobB sirtuin deacetylates RprY. Acetylation reduced the DNA binding of RprY. Induced oxidative stress decreased production of RprY in vivo, increased its acetylation and increased expression of nqrA. Conclusions: We propose that to compensate for the loss of RprX, P. gingivalis has evolved a novel mechanism to inactivate RprY through acetylation.
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Affiliation(s)
- Yuqing Li
- Department of Microbiology, The Forsyth Institute, Cambridge, MA, USA.,State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China
| | - Karthik Krishnan
- Department of Microbiology, The Forsyth Institute, Cambridge, MA, USA.,Office of Dean of Research and Graduate Studies, Shiv Nadar University, Gautam Buddha Nagar, India
| | - Margaret J Duncan
- Department of Microbiology, The Forsyth Institute, Cambridge, MA, USA
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14
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Mattos-Graner RO, Duncan MJ. Two-component signal transduction systems in oral bacteria. J Oral Microbiol 2017; 9:1400858. [PMID: 29209465 PMCID: PMC5706477 DOI: 10.1080/20002297.2017.1400858] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 11/01/2017] [Indexed: 01/03/2023] Open
Abstract
We present an overview of how members of the oral microbiota respond to their environment by regulating gene expression through two-component signal transduction systems (TCSs) to support conditions compatible with homeostasis in oral biofilms or drive the equilibrium toward dysbiosis in response to environmental changes. Using studies on the sub-gingival Gram-negative anaerobe Porphyromonas gingivalis and Gram-positive streptococci as examples, we focus on the molecular mechanisms involved in activation of TCS and species specificities of TCS regulons.
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Affiliation(s)
- Renata O. Mattos-Graner
- Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas – UNICAMP, São Paulo, Brazil
| | - Margaret J. Duncan
- Department of Oral Medicine, Infection and Immunity, The Forsyth Institute, Cambridge, MA, USA
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15
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Ho MH, Lamont RJ, Xie H. Identification of Streptococcus cristatus peptides that repress expression of virulence genes in Porphyromonas gingivalis. Sci Rep 2017; 7:1413. [PMID: 28469253 PMCID: PMC5431200 DOI: 10.1038/s41598-017-01551-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 03/27/2017] [Indexed: 12/23/2022] Open
Abstract
Dental plaque is a complex multispecies biofilm, and is a direct precursor of periodontal disease. The virulence of periodontal pathogens, such as Porphyromonas gingivalis, is expressed in the context of this polymicrobial community. Previously, we reported an antagonistic relationship between Streptococcus cristatus and P. gingivalis, and identified arginine deiminase (ArcA) of S. cristatus as the signaling molecule to which P. gingivalis responds by repressing the expression and production of FimA protein. Here we demonstrate that direct interaction between P. gingivalis and S. cristatus is necessary for the cell-cell communication. Two surface proteins of P. gingivalis, PGN_0294 and PGN_0806, were found to interact with S. cristatus ArcA. Using a peptide array analysis, we identified several P. gingivalis-binding sites of ArcA, which led to the discovery of an 11-mer peptide with the native sequence of ArcA that repressed expression of fimbriae and of gingipains. These data indicate that a functional motif of ArcA is sufficient to selectively alter virulence gene expression in P. gingivalis, and PGN_0294 and PGN_0806 may serve as receptors for ArcA. Our findings provide a molecular basis for future rational design of agents that interfere with the initiation and formation of a P. gingivalis-induced pathogenic community.
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Affiliation(s)
- Meng-Hsuan Ho
- Department of Oral Biology, Meharry Medical College, Nashville, TN, 37208, United States
| | - Richard J Lamont
- Department of Oral Immunology and Infectious Diseases, University of Louisville, Louisville, KY, 40202, United States
| | - Hua Xie
- Department of Oral Biology, Meharry Medical College, Nashville, TN, 37208, United States.
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16
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Hendrickson EL, Beck DAC, Miller DP, Wang Q, Whiteley M, Lamont RJ, Hackett M. Insights into Dynamic Polymicrobial Synergy Revealed by Time-Coursed RNA-Seq. Front Microbiol 2017; 8:261. [PMID: 28293219 PMCID: PMC5329018 DOI: 10.3389/fmicb.2017.00261] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 02/07/2017] [Indexed: 01/31/2023] Open
Abstract
Many bacterial infections involve polymicrobial communities in which constituent organisms are synergistically pathogenic. Periodontitis, a commonly occurring chronic inflammatory disorder, is induced by multispecies bacterial communities. The periodontal keystone pathogen Porphyromonas gingivalis and the accessory pathogen Streptococcus gordonii exhibit polymicrobial synergy in animal models of disease. Mechanisms of co-adhesion and community formation by P. gingivalis and S. gordonii are well-established; however, little is known regarding the basis for increased pathogenicity. In this study we used time-coursed RNA-Seq to comprehensively and quantitatively examine the dynamic transcriptional landscape of P. gingivalis in a model consortium with S. gordonii. Genes encoding a number of potential virulence determinants had higher relative mRNA levels in the context of dual species model communities than P. gingivalis alone, including adhesins, the Type IX secretion apparatus, and tetratricopeptide repeat (TPR) motif proteins. In contrast, genes encoding conjugation systems and many of the stress responses showed lower levels of expression in P. gingivalis. A notable exception to reduced abundance of stress response transcripts was the genes encoding components of the oxidative stress-related OxyR regulon, indicating an adaptation of P. gingivalis to detoxify peroxide produced by the streptococcus. Collectively, the results are consistent with evolutionary adaptation of P. gingivalis to a polymicrobial oral environment, one outcome of which is increased pathogenic potential.
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Affiliation(s)
- Erik L Hendrickson
- Center for Microbial Proteomics and Chemical Engineering, University of Washington Seattle, WA, USA
| | - David A C Beck
- Center for Microbial Proteomics and Chemical Engineering, University of WashingtonSeattle, WA, USA; eScience Institute, University of WashingtonSeattle, WA, USA
| | - Daniel P Miller
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry Louisville, KY, USA
| | - Qian Wang
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry Louisville, KY, USA
| | - Marvin Whiteley
- Department of Molecular Biosciences, University of Texas at Austin Austin, TX, USA
| | - Richard J Lamont
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry Louisville, KY, USA
| | - Murray Hackett
- Center for Microbial Proteomics and Chemical Engineering, University of Washington Seattle, WA, USA
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17
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Kadowaki T, Yukitake H, Naito M, Sato K, Kikuchi Y, Kondo Y, Shoji M, Nakayama K. A two-component system regulates gene expression of the type IX secretion component proteins via an ECF sigma factor. Sci Rep 2016; 6:23288. [PMID: 26996145 PMCID: PMC4800418 DOI: 10.1038/srep23288] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 03/03/2016] [Indexed: 12/19/2022] Open
Abstract
The periodontopathogen Porphyromonas gingivalis secretes potent pathogenic proteases, gingipains, via the type IX secretion system (T9SS). This system comprises at least 11 components; however, the regulatory mechanism of their expression has not yet been elucidated. Here, we found that the PorY (PGN_2001)-PorX (PGN_1019)-SigP (PGN_0274) cascade is involved in the regulation of T9SS. Surface plasmon resonance (SPR) analysis revealed a direct interaction between a recombinant PorY (rPorY) and a recombinant PorX (rPorX). rPorY autophosphorylated and transferred a phosphoryl group to rPorX in the presence of Mn2+. These results demonstrate that PorX and PorY act as a response regulator and a histidine kinase, respectively, of a two component system (TCS), although they are separately encoded on the chromosome. T9SS component-encoding genes were down-regulated in a mutant deficient in a putative extracytoplasmic function (ECF) sigma factor, PGN_0274 (SigP), similar to the porX mutant. Electrophoretic gel shift assays showed that rSigP bound to the putative promoter regions of T9SS component-encoding genes. The SigP protein was lacking in the porX mutant. Co-immunoprecipitation and SPR analysis revealed the direct interaction between SigP and PorX. Together, these results indicate that the PorXY TCS regulates T9SS-mediated protein secretion via the SigP ECF sigma factor.
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Affiliation(s)
- Tomoko Kadowaki
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan.,Division of Frontier Life Science, Department of Medical and Dental Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan
| | - Hideharu Yukitake
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan
| | - Mariko Naito
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan
| | - Keiko Sato
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan
| | - Yuichiro Kikuchi
- Department of Microbiology, Tokyo Dental College, Tokyo 101-0061, Japan
| | - Yoshio Kondo
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan.,Department of Pediatric Dentistry, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan
| | - Mikio Shoji
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan
| | - Koji Nakayama
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan
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18
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Klein BA, Chen T, Scott JC, Koenigsberg AL, Duncan MJ, Hu LT. Identification and characterization of a minisatellite contained within a novel miniature inverted-repeat transposable element (MITE) of Porphyromonas gingivalis. Mob DNA 2015; 6:18. [PMID: 26448788 PMCID: PMC4596501 DOI: 10.1186/s13100-015-0049-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 09/23/2015] [Indexed: 12/26/2022] Open
Abstract
Background Repetitive regions of DNA and transposable elements have been found to constitute large percentages of eukaryotic and prokaryotic genomes. Such elements are known to be involved in transcriptional regulation, host-pathogen interactions and genome evolution. Results We identified a minisatellite contained within a miniature inverted-repeat transposable element (MITE) in Porphyromonas gingivalis. The P. gingivalis minisatellite and associated MITE, named ‘BrickBuilt’, comprises a tandemly repeating twenty-three nucleotide DNA sequence lacking spacer regions between repeats, and with flanking ‘leader’ and ‘tail’ subunits that include small inverted-repeat ends. Forms of the BrickBuilt MITE are found 19 times in the genome of P. gingivalis strain ATCC 33277, and also multiple times within the strains W83, TDC60, HG66 and JCVI SC001. BrickBuilt is always located intergenically ranging between 49 and 591 nucleotides from the nearest upstream and downstream coding sequences. Segments of BrickBuilt contain promoter elements with bidirectional transcription capabilities. Conclusions We performed a bioinformatic analysis of BrickBuilt utilizing existing whole genome sequencing, microarray and RNAseq data, as well as performing in vitro promoter probe assays to determine potential roles, mechanisms and regulation of the expression of these elements and their affect on surrounding loci. The multiplicity, localization and limited host range nature of MITEs and MITE-like elements in P. gingivalis suggest that these elements may play an important role in facilitating genome evolution as well as modulating the transcriptional regulatory system. Electronic supplementary material The online version of this article (doi:10.1186/s13100-015-0049-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Brian A Klein
- Department of Molecular Biology and Microbiology, Tufts University Sackler School of Biomedical Sciences, Boston, MA 02111 USA ; Department of Microbiology, The Forsyth Institute, Cambridge, MA 02142 USA
| | - Tsute Chen
- Department of Microbiology, The Forsyth Institute, Cambridge, MA 02142 USA
| | - Jodie C Scott
- Department of Microbiology, The Forsyth Institute, Cambridge, MA 02142 USA
| | - Andrea L Koenigsberg
- Department of Molecular Biology and Microbiology, Tufts University Sackler School of Biomedical Sciences, Boston, MA 02111 USA
| | - Margaret J Duncan
- Department of Microbiology, The Forsyth Institute, Cambridge, MA 02142 USA
| | - Linden T Hu
- Department of Molecular Biology and Microbiology, Tufts University Sackler School of Biomedical Sciences, Boston, MA 02111 USA
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19
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Glew MD, Veith PD, Chen D, Seers CA, Chen YY, Reynolds EC. Blue native-PAGE analysis of membrane protein complexes in Porphyromonas gingivalis. J Proteomics 2014; 110:72-92. [DOI: 10.1016/j.jprot.2014.07.033] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 07/01/2014] [Accepted: 07/20/2014] [Indexed: 11/30/2022]
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20
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Wright CJ, Wu H, Melander RJ, Melander C, Lamont RJ. Disruption of heterotypic community development by Porphyromonas gingivalis with small molecule inhibitors. Mol Oral Microbiol 2014; 29:185-93. [PMID: 24899524 DOI: 10.1111/omi.12060] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/01/2014] [Indexed: 12/13/2022]
Abstract
Porphyromonas gingivalis is one of the main etiological organisms in periodontal disease. On oral surfaces P. gingivalis is a component of multispecies biofilm communities and can modify the pathogenic potential of the community as a whole. Accumulation of P. gingivalis in communities is facilitated by interspecies binding and communication with the antecedent colonizer Streptococcus gordonii. In this study we screened a library of small molecules to identify structures that could serve as lead compounds for the development of inhibitors of P. gingivalis community development. Three small molecules were identified that effectively inhibited accumulation of P. gingivalis on a substratum of S. gordonii. The structures of the small molecules are derived from the marine alkaloids oroidin and bromoageliferin and contain a 2-aminoimidazole or 2-aminobenzimidazole moiety. The most active compounds reduced expression of mfa1 and fimA in P. gingivalis, genes encoding the minor and major fimbrial subunits, respectively. These fimbrial adhesins are necessary for P. gingivalis co-adhesion with S. gordonii. These results demonstrate the potential for a small molecular inhibitor-based approach to the prevention of diseases associated with P. gingivalis.
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Affiliation(s)
- C J Wright
- Oral Health and Systemic Disease, University of Louisville, Louisville, KY, USA
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21
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Identification of a diguanylate cyclase and its role in Porphyromonas gingivalis virulence. Infect Immun 2014; 82:2728-35. [PMID: 24733094 DOI: 10.1128/iai.00084-14] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Porphyromonas gingivalis is a Gram-negative obligate anaerobic bacterium and is considered a keystone pathogen in the initiation of periodontitis, one of the most widespread infectious diseases. Bacterial bis-(3'-5') cyclic GMP (cyclic di-GMP [c-di-GMP]) serves as a second messenger and is involved in modulating virulence factors in numerous bacteria. However, the role of this second messenger has not been investigated in P. gingivalis, mainly due to a lack of an annotation regarding diguanylate cyclases (DGCs) in this bacterium. Using bioinformatics tools, we found a protein, PGN_1932, containing a GGDEF domain. A deletion mutation in the pgn_1932 gene had a significant effect on the intracellular c-di-GMP level in P. gingivalis. Genetic analysis showed that expression of the fimA and rgpA genes, encoding the major protein subunit of fimbriae and an arginine-specific proteinase, respectively, was downregulated in the pgn_1932 mutant. Correspondingly, FimA protein production and the fimbrial display on the mutant were significantly reduced. Mutations in the pgn_1932 gene also had a significant impact on the adhesive and invasive capabilities of P. gingivalis, which are required for its pathogenicity. These findings provide evidence that the PGN_1932 protein is both responsible for synthesizing c-di-GMP and involved in biofilm formation and host cell invasion by P. gingivalis by controlling the expression and biosynthesis of FimA.
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22
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Kerr JE, Abramian JR, Dao DHV, Rigney TW, Fritz J, Pham T, Gay I, Parthasarathy K, Wang BY, Zhang W, Tribble GD. Genetic exchange of fimbrial alleles exemplifies the adaptive virulence strategy of Porphyromonas gingivalis. PLoS One 2014; 9:e91696. [PMID: 24626479 PMCID: PMC3953592 DOI: 10.1371/journal.pone.0091696] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 02/15/2014] [Indexed: 11/19/2022] Open
Abstract
Porphyromonas gingivalis is a gram–negative anaerobic bacterium, a member of the human oral microbiome, and a proposed “keystone” pathogen in the development of chronic periodontitis, an inflammatory disease of the gingiva. P. gingivalis is a genetically diverse species, and is able to exchange chromosomal DNA between strains by natural competence and conjugation. In this study, we investigate the role of horizontal DNA transfer as an adaptive process to modify behavior, using the major fimbriae as our model system, due to their critical role in mediating interactions with the host environment. We show that P. gingivalis is able to exchange fimbrial allele types I and IV into four distinct strain backgrounds via natural competence. In all recombinants, we detected a complete exchange of the entire fimA allele, and the rate of exchange varies between the different strain backgrounds. In addition, gene exchange within other regions of the fimbrial genetic locus was identified. To measure the biological implications of these allele swaps we compared three genotypes of fimA in an isogenic background, strain ATCC 33277. We demonstrate that exchange of fimbrial allele type results in profound phenotypic changes, including the quantity of fimbriae elaborated, membrane blebbing, auto-aggregation and other virulence-associated phenotypes. Replacement of the type I allele with either the type III or IV allele resulted in increased invasion of gingival fibroblast cells relative to the isogenic parent strain. While genetic variability is known to impact host-microbiome interactions, this is the first study to quantitatively assess the adaptive effect of exchanging genes within the pan genome cloud. This is significant as it presents a potential mechanism by which opportunistic pathogens may acquire the traits necessary to modify host-microbial interactions.
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Affiliation(s)
- Jennifer E. Kerr
- Department of Periodontics and Dental Hygiene, School of Dentistry, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Jared R. Abramian
- Department of Periodontics and Dental Hygiene, School of Dentistry, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Doan-Hieu V. Dao
- Department of Periodontics and Dental Hygiene, School of Dentistry, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Todd W. Rigney
- Department of Periodontics and Dental Hygiene, School of Dentistry, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Jamie Fritz
- Department of Periodontics and Dental Hygiene, School of Dentistry, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Tan Pham
- Department of Periodontics and Dental Hygiene, School of Dentistry, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Isabel Gay
- Department of Periodontics and Dental Hygiene, School of Dentistry, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Kavitha Parthasarathy
- Department of Periodontics and Dental Hygiene, School of Dentistry, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Bing-yan Wang
- Department of Periodontics and Dental Hygiene, School of Dentistry, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Wenjian Zhang
- Department of Diagnostic and Biomedical Sciences, School of Dentistry, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Gena D. Tribble
- Department of Periodontics and Dental Hygiene, School of Dentistry, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- * E-mail:
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23
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Scott JC, Klein BA, Duran-Pinedo A, Hu L, Duncan MJ. A two-component system regulates hemin acquisition in Porphyromonas gingivalis. PLoS One 2013; 8:e73351. [PMID: 24039921 PMCID: PMC3764172 DOI: 10.1371/journal.pone.0073351] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 07/17/2013] [Indexed: 01/19/2023] Open
Abstract
Porphyromonas gingivalis is a Gram-negative oral anaerobe associated with infection of the periodontia. The organism has a small number of two-component signal transduction systems, and after comparing genome sequences of strains W83 and ATCC 33277 we discovered that the latter was mutant in histidine kinase (PGN_0752), while the cognate response regulator (PGN_0753) remained intact. Microarray-based transcriptional profiling and ChIP-seq assays were carried out with an ATCC 33277 transconjugant containing the functional histidine kinase from strain W83 (PG0719). The data showed that the regulon of this signal transduction system contained genes that were involved in hemin acquisition, including gingipains, at least three transport systems, as well as being self-regulated. Direct regulation by the response regulator was confirmed by electrophoretic mobility shift assays. In addition, the system appears to be activated by hemin and the regulator acts as both an activator and repressor.
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Affiliation(s)
- Jodie C. Scott
- Department of Microbiology, The Forsyth Institute, Cambridge, Massachusetts, United States of America
| | - Brian A. Klein
- Department of Molecular Biology and Microbiology, Tufts University Sackler School of Biomedical Sciences, Boston, Massachusetts, United States of America
| | - Ana Duran-Pinedo
- Department of Microbiology, The Forsyth Institute, Cambridge, Massachusetts, United States of America
| | - Linden Hu
- Division of Geographic Medicine and Infectious Disease, Tufts Medical Center, Boston, Massachusetts, United States of America
| | - Margaret J. Duncan
- Department of Microbiology, The Forsyth Institute, Cambridge, Massachusetts, United States of America
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Nagano K. FimA Fimbriae of the Periodontal Disease-associated Bacterium Porphyromonas gingivalis. YAKUGAKU ZASSHI 2013; 133:963-74. [DOI: 10.1248/yakushi.13-00177] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Keiji Nagano
- Department of Microbiology, School of Dentistry, Aichi Gakuin University
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Enersen M, Nakano K, Amano A. Porphyromonas gingivalis fimbriae. J Oral Microbiol 2013; 5:20265. [PMID: 23667717 PMCID: PMC3647041 DOI: 10.3402/jom.v5i0.20265] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 04/11/2013] [Accepted: 04/11/2013] [Indexed: 12/22/2022] Open
Abstract
Marginal periodontitis is not a homogeneous disease but is rather influenced by an intricate set of host susceptibility differences as well as diversities in virulence among the harbored organisms. It is likely that clonal heterogeneity of subpopulations with both high and low levels of pathogenicity exists among organisms harbored by individuals with negligible, slight, or even severe periodontal destruction. Therefore, specific virulent clones of periodontal pathogens may cause advanced and/or aggressive periodontitis. Porphyromonas gingivalis is a predominant periodontal pathogen that expresses a number of potential virulence factors involved in the pathogenesis of periodontitis, and accumulated evidence shows that its expression of heterogenic virulence properties is dependent on clonal diversity. Fimbriae are considered to be critical factors that mediate bacterial interactions with and invasion of host tissues, with P. gingivalis shown to express two distinct fimbria-molecules, long and short fimbriae, on the cell surface, both of which seem to be involved in development of periodontitis. Long fimbriae are classified into six types (I to V and Ib) based on the diversity of fimA genes encoding FimA (a subunit of long fimbriae). Studies of clones with type II fimA have revealed their significantly greater adhesive and invasive capabilities as compared to other fimA type clones. Long and short fimbriae induce various cytokine expressions such as IL-1α, IL-β, IL-6, and TNF-α, which result in alveolar bone resorption. Although the clonal diversity of short fimbriae is unclear, distinct short fimbria-molecules have been found in different strains. These fimbriae variations likely influence the development of periodontal disease.
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Affiliation(s)
- Morten Enersen
- Institute of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
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Wright CJ, Burns LH, Jack AA, Back CR, Dutton LC, Nobbs AH, Lamont RJ, Jenkinson HF. Microbial interactions in building of communities. Mol Oral Microbiol 2013; 28:83-101. [PMID: 23253299 PMCID: PMC3600090 DOI: 10.1111/omi.12012] [Citation(s) in RCA: 130] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/31/2012] [Indexed: 12/31/2022]
Abstract
Establishment of a community is considered to be essential for microbial growth and survival in the human oral cavity. Biofilm communities have increased resilience to physical forces, antimicrobial agents and nutritional variations. Specific cell-to-cell adherence processes, mediated by adhesin-receptor pairings on respective microbial surfaces, are able to direct community development. These interactions co-localize species in mutually beneficial relationships, such as streptococci, veillonellae, Porphyromonas gingivalis and Candida albicans. In transition from the planktonic mode of growth to a biofilm community, microorganisms undergo major transcriptional and proteomic changes. These occur in response to sensing of diffusible signals, such as autoinducer molecules, and to contact with host tissues or other microbial cells. Underpinning many of these processes are intracellular phosphorylation events that regulate a large number of microbial interactions relevant to community formation and development.
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Affiliation(s)
- Christopher J. Wright
- Department of Oral Health and Systemic Disease, University of Louisville, 570 South Preston Street, Louisville, Kentucky, 40202, USA
| | - Logan H. Burns
- Department of Oral Health and Systemic Disease, University of Louisville, 570 South Preston Street, Louisville, Kentucky, 40202, USA
| | - Alison A. Jack
- School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS12LY, UK
| | - Catherine R. Back
- School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS12LY, UK
| | - Lindsay C. Dutton
- School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS12LY, UK
| | - Angela H. Nobbs
- School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS12LY, UK
| | - Richard J. Lamont
- Department of Oral Health and Systemic Disease, University of Louisville, 570 South Preston Street, Louisville, Kentucky, 40202, USA
| | - Howard F. Jenkinson
- School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS12LY, UK
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A novel class of lipoprotein lipase-sensitive molecules mediates Toll-like receptor 2 activation by Porphyromonas gingivalis. Infect Immun 2013; 81:1277-86. [PMID: 23381996 DOI: 10.1128/iai.01036-12] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Infection by the chronic periodontitis-associated pathogen Porphyromonas gingivalis activates a Toll-like receptor 2 (TLR2) response that triggers inflammation in the host but also promotes bacterial persistence. Our aim was to define ligands on the surfaces of intact P. gingivalis cells that determine its ability to activate TLR2. Molecules previously reported as TLR2 agonists include lipopolysaccharide (LPS), fimbriae, the lipoprotein PG1828, and phosphoceramides. We demonstrate that these molecules do not comprise the major factors responsible for stimulating TLR2 by whole bacterial cells. First, P. gingivalis mutants devoid of the reported protein agonists, PG1828 and fimbriae, activate TLR2 as strongly as the wild type. Second, two-phase extraction of whole bacteria resulted in a preponderance of TLR2 agonist activity partitioning to the hydrophilic phase, demonstrating that phosphoceramides are not a major TLR2 ligand. Third, analysis of LPS revealed that TLR2 activation is independent of lipid A structural variants. Instead, activation of TLR2 and TLR2/TLR1 by LPS is in large part due to copurifying molecules that are sensitive to the action of the enzyme lipoprotein lipase. Strikingly, intact P. gingivalis bacterial cells treated with lipoprotein lipase were attenuated in their ability to activate TLR2. We propose that a novel class of molecules comprised by lipoproteins constitutes the major determinants that confer to P. gingivalis the ability to stimulate TLR2 signaling.
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Priyadarshini R, Cugini C, Arndt A, Chen T, Tjokro NO, Goodman SD, Davey ME. The nucleoid-associated protein HUβ affects global gene expression in Porphyromonas gingivalis. MICROBIOLOGY-SGM 2012; 159:219-229. [PMID: 23175503 DOI: 10.1099/mic.0.061002-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
HU is a non-sequence-specific DNA-binding protein and one of the most abundant nucleoid-associated proteins in the bacterial cell. Like Escherichia coli, the genome of Porphyromonas gingivalis is predicted to encode both the HUα (PG1258) and the HUβ (PG0121) subunit. We have previously reported that PG0121 encodes a non-specific DNA-binding protein and that PG0121 is co-transcribed with the K-antigen capsule synthesis operon. We also reported that deletion of PG0121 resulted in downregulation of capsule operon expression and produced a P. gingivalis strain that is phenotypically deficient in surface polysaccharide production. Here, we show through complementation experiments in an E. coli MG1655 hupAB double mutant strain that PG0121 encodes a functional HU homologue. Microarray and quantitative RT-PCR analysis were used to further investigate global transcriptional regulation by HUβ using comparative expression profiling of the PG0121 (HUβ) mutant strain to the parent strain, W83. Our analysis determined that expression of genes encoding proteins involved in a variety of biological functions, including iron acquisition, cell division and translation, as well as a number of predicted nucleoid associated proteins were altered in the PG0121 mutant. Phenotypic and quantitative real-time-PCR (qRT-PCR) analyses determined that under iron-limiting growth conditions, cell division and viability were defective in the PG0121 mutant. Collectively, our studies show that PG0121 does indeed encode a functional HU homologue, and HUβ has global regulatory functions in P. gingivalis; it affects not only production of capsular polysaccharides but also expression of genes involved in basic functions, such as cell wall synthesis, cell division and iron uptake.
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Affiliation(s)
- Richa Priyadarshini
- Department of Oral Medicine Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
- Department of Molecular Genetics, The Forsyth Institute, Cambridge, MA, USA
| | - Carla Cugini
- Department of Oral Medicine Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
- Department of Molecular Genetics, The Forsyth Institute, Cambridge, MA, USA
| | - Annette Arndt
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Tsute Chen
- Department of Oral Medicine Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
- Department of Molecular Genetics, The Forsyth Institute, Cambridge, MA, USA
| | - Natalia O Tjokro
- Division of Biomedical Sciences, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - Steven D Goodman
- Division of Biomedical Sciences, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - Mary E Davey
- Department of Oral Medicine Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
- Department of Molecular Genetics, The Forsyth Institute, Cambridge, MA, USA
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Hirano T, Beck DAC, Wright CJ, Demuth DR, Hackett M, Lamont RJ. Regulon controlled by the GppX hybrid two component system in Porphyromonas gingivalis. Mol Oral Microbiol 2012. [PMID: 23194602 DOI: 10.1111/omi.12007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The periodontal pathogen Porphyromonas gingivalis experiences a number of environmental conditions in the oral cavity, and must monitor and respond to a variety of environmental cues. However, the organism possesses only five full two-component systems, one of which is the hybrid system GppX. To investigate the regulon controlled by GppX we performed RNA-Seq on a ΔGppX mutant. Fifty-three genes were upregulated and 37 genes were downregulated in the ΔGppX mutant. Pathway analyses revealed no systemic function for GppX under nutrient-replete conditions; however, over 40% of the differentially abundant genes were annotated as encoding hypothetical proteins indicating a novel role for GppX. Abundance of small RNA was, in general, not affected by the absence of GppX. To further define the role of GppX with respect to regulation of a hypothetical protein observed with the greatest significant relative abundance change relative to a wild-type control, PGN_0151, we constructed a series of strains in which the ΔgppX mutation was complemented with a GppX protein containing specific domain and phosphotransfer mutations. The transmembrane domains, the DNA-binding domain and the phosphotransfer residues were all required for regulation of PGN_0151. In addition, binding of GppX to the PGN_0151 promoter regions was confirmed by an electrophoretic mobility shift assay. Both the ΔGppX mutant and a ΔPGN_0151 mutant were deficient in monospecies biofilm formation, suggesting a role for the GppX-PGN_0151 regulon in colonization and survival of the organism.
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Affiliation(s)
- T Hirano
- Center for Oral Health and Systemic Disease, School of Dentistry, University of Louisville, Louisville, KY, USA
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Porphyromonas gingivalis FimA fimbriae: fimbrial assembly by fimA alone in the fim gene cluster and differential antigenicity among fimA genotypes. PLoS One 2012; 7:e43722. [PMID: 22970139 PMCID: PMC3436787 DOI: 10.1371/journal.pone.0043722] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 07/23/2012] [Indexed: 11/19/2022] Open
Abstract
The periodontal pathogen Porphyromonas gingivalis colonizes largely through FimA fimbriae, composed of polymerized FimA encoded by fimA. fimA exists as a single copy within the fim gene cluster (fim cluster), which consists of seven genes: fimX, pgmA and fimA-E. Using an expression vector, fimA alone was inserted into a mutant from which the whole fim cluster was deleted, and the resultant complement exhibited a fimbrial structure. Thus, the genes of the fim cluster other than fimA were not essential for the assembly of FimA fimbriae, although they were reported to influence FimA protein expression. It is known that there are various genotypes for fimA, and it was indicated that the genotype was related to the morphological features of FimA fimbriae, especially the length, and to the pathogenicity of the bacterium. We next complemented the fim cluster-deletion mutant with fimA genes cloned from P. gingivalis strains including genotypes I to V. All genotypes showed a long fimbrial structure, indicating that FimA itself had nothing to do with regulation of the fimbrial length. In FimA fimbriae purified from the complemented strains, types I, II, and III showed slightly higher thermostability than types IV and V. Antisera of mice immunized with each purified fimbria principally recognized the polymeric, structural conformation of the fimbriae, and showed low cross-reactivity among genotypes, indicating that FimA fimbriae of each genotype were antigenically different. Additionally, the activity of a macrophage cell line stimulated with the purified fimbriae was much lower than that induced by Escherichia coli lipopolysaccharide.
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31
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Nagano K, Abiko Y, Yoshida Y, Yoshimura F. Porphyromonas gingivalis FimA fimbriae: Roles of the fim gene cluster in the fimbrial assembly and antigenic heterogeneity among fimA genotypes. J Oral Biosci 2012. [DOI: 10.1016/j.job.2012.07.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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OxyR activation in Porphyromonas gingivalis in response to a hemin-limited environment. Infect Immun 2012; 80:3471-80. [PMID: 22825453 DOI: 10.1128/iai.00680-12] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Porphyromonas gingivalis is a Gram-negative obligately anaerobic bacterium associated with several forms of periodontal disease, most closely with chronic periodontitis. Previous studies demonstrated that OxyR plays an important role in the aerotolerance of P. gingivalis by upregulating the expression of oxidative-stress genes. Increases in oxygen tension and in H(2)O(2) both induce activation of OxyR. It is also known that P. gingivalis requires hemin as an iron source for its growth. In this study, we found that a hemin-limited growth environment significantly enhanced OxyR activity in P. gingivalis. As a result, expression of sod, dps, and ahpC was also upregulated. Using a chromatin immunoprecipitation quantitative PCR (qPCR) analysis, DNA binding of activated OxyR to the promoter of the sod gene was enhanced in P. gingivalis grown under hemin-limited conditions compared to excess-hemin conditions. Cellular tolerance of H(2)O(2) was also enhanced when hemin was limited in the growth medium of P. gingivalis. Our work supports a model in which hemin serves as a signal for the regulation of OxyR activity and indicates that P. gingivalis coordinately regulates expression of oxidative-stress-related genes by this hemin concentration-dependent pathway.
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Zheng C, Wu J, Xie H. Differential expression and adherence of Porphyromonas gingivalis FimA genotypes. Mol Oral Microbiol 2011; 26:388-95. [PMID: 22053966 DOI: 10.1111/j.2041-1014.2011.00626.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Porphyromonas gingivalis is a primary pathogen involved in the initiation and progression of adult chronic periodontitis. Its colonization on oral surfaces is a necessary first step leading to infection. FimA, a subunit protein of major (long) fimbriae, is a well-known virulence factor. Based on its nucleotide sequence, FimA is classified into several genotypes. We compared here the transcriptional levels of the fimA gene in several P. gingivalis strains using real-time polymerase chain reaction analysis, fimbrial display on the P. gingivalis surface using transmission electronic microscopy, and the adherence competencies of P. gingivalis strains carrying different types of FimAs towards saliva and Streptococcus gordonii surfaces using mutagenesis analysis. We demonstrated differential expression of each fimA gene in these P. gingivalis strains. A correlation of the transcription level of fimA and binding activity of P. gingivalis was revealed. We show that P. gingivalis strains with genotype I and II of FimA are efficient in interaction with saliva or S. gordonii. This work highlights the important role of FimA type I and II in P. gingivalis attachment to oral surfaces.
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Affiliation(s)
- C Zheng
- Department of Oral Biology, School of Dentistry, Meharry Medical College, Nashville, TN 37208, USA
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Niwa D, Nishikawa K, Nakamura H. A hybrid two-component system of Tannerella forsythia affects autoaggregation and post-translational modification of surface proteins. FEMS Microbiol Lett 2011; 318:189-96. [PMID: 21385202 DOI: 10.1111/j.1574-6968.2011.02256.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Tannerella forsythia is a Gram-negative oral anaerobe closely associated with both periodontal and periapical diseases. The ORF TF0022 of strain ATCC 43037 encodes a hybrid two-component system consisting of an N-terminal histidine kinase and a C-terminal response regulator. Disruption of the TF0022 locus enhanced autoaggregation of the broth-cultured cells. Comparative proteome analyses revealed that two S-layer proteins in the TF0022 mutant exhibited decreased apparent masses by denaturing gel electrophoresis, suggesting a deficiency in post-translational modification. Furthermore, the mutant decreased the production of a glycosyltransferase encoded by TF1061 that is located in a putative glycosylation-related gene cluster. Quantitative real-time PCR revealed reduced transcription of TF1061 and the associated genes in the TF0022 mutant. These results indicate that TF0022 upregulates the expression of the glycosylation-related genes and suggest modulation of the autoaggregation of T. forsythia cells by a possible post-translational modification of cell-surface components.
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Affiliation(s)
- Daisuke Niwa
- Department of Endodontics, School of Dentistry, Aichi Gakuin University, Chikusa-ku, Nagoya, Japan
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35
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Christopher AB, Arndt A, Cugini C, Davey ME. A streptococcal effector protein that inhibits Porphyromonas gingivalis biofilm development. MICROBIOLOGY-SGM 2010; 156:3469-3477. [PMID: 20705665 DOI: 10.1099/mic.0.042671-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Dental plaque formation is a developmental process involving cooperation and competition within a diverse microbial community, approximately 70 % of which is composed of an array of streptococci during the early stages of supragingival plaque formation. In this study, 79 cell-free culture supernatants from a variety of oral streptococci were screened to identify extracellular compounds that inhibit biofilm formation by the oral anaerobe Porphyromonas gingivalis strain 381. The majority of the streptococcal supernatants (61 isolates) resulted in lysis of P. gingivalis cells, and some (17 isolates) had no effect on cell viability, growth or biofilm formation. One strain, however, produced a supernatant that abolished biofilm formation without affecting growth rate. Analysis of this activity led to the discovery that a 48 kDa protein was responsible for the inhibition. Protein sequence identification and enzyme activity assays identified the effector protein as an arginine deiminase. To identify the mechanism(s) by which this protein inhibits biofilm formation, we began by examining the expression levels of genes encoding fimbrial subunits; surface structures known to be involved in biofilm development. Quantitative RT-PCR analysis revealed that exposure of P. gingivalis cells to this protein for 1 h resulted in the downregulation of genes encoding proteins that are the major subunits of two distinct types of thin, single-stranded fimbriae (fimA and mfa1). Furthermore, this downregulation occurred in the absence of arginine deiminase enzymic activity. Hence, our data indicate that P. gingivalis can sense this extracellular protein, produced by an oral streptococcus (Streptococcus intermedius), and respond by downregulating expression of cell-surface appendages required for attachment and biofilm development.
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Affiliation(s)
| | - Annette Arndt
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Carla Cugini
- Department of Molecular Genetics, The Forsyth Institute, Boston, MA, USA
| | - Mary E Davey
- Department of Molecular Genetics, The Forsyth Institute, Boston, MA, USA
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Nagano K, Hasegawa Y, Murakami Y, Nishiyama S, Yoshimura F. FimB regulates FimA fimbriation in Porphyromonas gingivalis. J Dent Res 2010; 89:903-8. [PMID: 20530728 DOI: 10.1177/0022034510370089] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The periodontitis-associated pathogen Porphyromonas gingivalis colonizes and forms a biofilm in gingival crevices through fimbriae. It is known that the often-used strains ATCC 33277 and 381 produce long FimA fimbriae. We found a possible nonsense mutation within fimB, immediately downstream from fimA, coding a major subunit of FimA fimbriae of the strains. Indeed, P. gingivalis strains, except for ATCC 33277 and 381, universally expressed FimB, the gene product of fimB. Electron micrographs revealed that a FimB-restored strain had short and dense, "toothbrush"-like, FimA fimbriae. FimA overexpression elongated the fimbriae, whereas FimB overexpression shortened them. FimB restoration increased production of FimA and its accessory proteins. Thus, FimB regulates the length and expression of FimA fimbriae. Additionally, FimB restoration significantly reduced the release of FimA fimbriae from the cell surface, suggesting that FimB functions as an anchor of the fimbriae. The restoration enhanced adherent activity as well.
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Affiliation(s)
- K Nagano
- Department of Microbiology, School of Dentistry, Aichi-Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya, Aichi 464-8650, Japan.
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38
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Histidine kinase-mediated production and autoassembly of Porphyromonas gingivalis fimbriae. J Bacteriol 2010; 192:1975-87. [PMID: 20118268 DOI: 10.1128/jb.01474-09] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Porphyromonas gingivalis, a Gram-negative oral anaerobe, is strongly associated with chronic adult periodontitis, and it utilizes FimA fimbriae to persistently colonize and evade host defenses in the periodontal crevice. The FimA-related gene cluster (the fim gene cluster) is positively regulated by the FimS-FimR two-component system. In this study, comparative analyses between fimbriate type strain ATCC 33277 and fimbria-deficient strain W83 revealed differences in their fimS loci, which encode FimS histidine kinase. Using a reciprocal gene exchange system, we established that FimS from W83 is malfunctional. Complementation analysis with chimeric fimS constructs revealed that W83 FimS has a defective kinase domain due to a truncated conserved G3 box motif that provides an ATP-binding pocket. The introduction of the functional fimS from 33277 restored the production, but not polymerization, of endogenous FimA subunits in W83. Further analyses with a fimA-exchanged W83 isogenic strain showed that even the fimbria-deficient W83 retains the ability to polymerize FimA from 33277, indicating the assembly of mature FimA by a primary structure-dependent mechanism. It also was shown that the substantial expression of 33277-type FimA fimbriae in the W83 derivative requires the introduction and expression of the functional 33277 fimS. These findings indicate that FimSR is the unique and universal regulatory system that activates the fim gene cluster in a fimA genotype-independent manner.
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Wang M, Liang S, Hosur KB, Domon H, Yoshimura F, Amano A, Hajishengallis G. Differential virulence and innate immune interactions of Type I and II fimbrial genotypes of Porphyromonas gingivalis. ACTA ACUST UNITED AC 2010; 24:478-84. [PMID: 19832800 DOI: 10.1111/j.1399-302x.2009.00545.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
INTRODUCTION The fimA-encoded fimbriae of the periodontal pathogen Porphyromonas gingivalis display genetic diversity. Type I fimbriated P. gingivalis (Pg-I) has been most widely studied at the molecular level, whereas Pg-II is the most frequent isolate from severe periodontitis. METHODS To investigate virulence differences between Types I and II fimbriae, we examined strains 33277 (Pg-I) and OMZ314 (Pg-II), reciprocal swap mutants (i.e. expressing the heterologous fimbrial type), and their respective FimA-deficient derivatives. These organisms were tested in a mouse periodontitis model and in interactions with mouse macrophages, a cell type that plays important roles in chronic infections. RESULTS Strain 33277 induced significantly more periodontal bone loss than OMZ314 and substitution of Type II fimbriae with Type I in OMZ314 resulted in a more virulent strain than the parent organism. However, the presence of Type II fimbriae was associated with increased proinflammatory and invasive activities in macrophages. CONCLUSION The inverse relationship between proinflammatory potential and ability to cause experimental periodontitis may suggest that an aggressive phenotype could provoke a host response that would compromise the persistence of the pathogen.
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Affiliation(s)
- M Wang
- Department of Periodontics/Oral Health and Systemic Disease, University of Louisville School of Dentistry, Louisville, KY 40292, USA
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40
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FimR and FimS: biofilm formation and gene expression in Porphyromonas gingivalis. J Bacteriol 2010; 192:1332-43. [PMID: 20061484 DOI: 10.1128/jb.01211-09] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Porphyromonas gingivalis is a late-colonizing bacterium of the subgingival dental plaque biofilm associated with periodontitis. Two P. gingivalis genes, fimR and fimS, are predicted to encode a two-component signal transduction system comprising a response regulator (FimR) and a sensor histidine kinase (FimS). In this study, we show that fimS and fimR, although contiguous on the genome, are not part of an operon. We inactivated fimR and fimS in both the afimbriated strain W50 and the fimbriated strain ATCC 33277 and demonstrated that both mutants formed significantly less biofilm than their respective wild-type strains. Quantitative reverse transcription-real-time PCR showed that expression of fimbriation genes was reduced in both the fimS and fimR mutants of strain ATCC 33277. The mutations had no effect, in either strain, on the P. gingivalis growth rate or on the response to hydrogen peroxide or growth at pH 9, at 41 degrees C, or at low hemin availability. Transcriptome analysis using DNA microarrays revealed that inactivation of fimS resulted in the differential expression of 10% of the P. gingivalis genome (>1.5-fold; P < 0.05). Notably genes encoding seven different transcriptional regulators, including the fimR gene and three extracytoplasmic sigma factor genes, were differentially expressed in the fimS mutant.
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Hasegawa Y, Iwami J, Sato K, Park Y, Nishikawa K, Atsumi T, Moriguchi K, Murakami Y, Lamont RJ, Nakamura H, Ohno N, Yoshimura F. Anchoring and length regulation of Porphyromonas gingivalis Mfa1 fimbriae by the downstream gene product Mfa2. MICROBIOLOGY-SGM 2009; 155:3333-3347. [PMID: 19589838 DOI: 10.1099/mic.0.028928-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Porphyromonas gingivalis, a causative agent of periodontitis, has at least two types of thin, single-stranded fimbriae, termed FimA and Mfa1 (according to the names of major subunits), which can be discriminated by filament length and by the size of their major fimbrilin subunits. FimA fimbriae are long filaments that are easily detached from cells, whereas Mfa1 fimbriae are short filaments that are tightly bound to cells. However, a P. gingivalis ATCC 33277-derived mutant deficient in mfa2, a gene downstream of mfa1, produced long filaments (10 times longer than those of the parent), easily detached from the cell surface, similar to FimA fimbriae. Longer Mfa1 fimbriae contributed to stronger autoaggregation of bacterial cells. Complementation of the mutant with the wild-type mfa2 allele in trans restored the parental phenotype. Mfa2 is present in the outer membrane of P. gingivalis, but does not co-purify with the Mfa1 fimbriae. However, co-immunoprecipitation demonstrated that Mfa2 and Mfa1 are associated with each other in whole P. gingivalis cells. Furthermore, immunogold microscopy, including double labelling, confirmed that Mfa2 was located on the cell surface and likely associated with Mfa1 fimbriae. Mfa2 may therefore play a role as an anchor for the Mfa1 fimbriae and also as a regulator of Mfa1 filament length. Two additional downstream genes (pgn0289 and pgn0290) are co-transcribed with mfa1 (pgn0287) and mfa2 (pgn0288), and proteins derived from pgn0289, pgn0290 and pgn0291 appear to be accessory fimbrial components.
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Affiliation(s)
- Yoshiaki Hasegawa
- Department of Microbiology, School of Dentistry, Aichi-Gakuin University, Nagoya, Aichi 464-8650, Japan
| | - Jun Iwami
- Department of Endodontology, School of Dentistry, Aichi-Gakuin University, Nagoya, Aichi 464-8650, Japan.,Department of Microbiology, School of Dentistry, Aichi-Gakuin University, Nagoya, Aichi 464-8650, Japan
| | - Keiko Sato
- Department of Microbiology, School of Dentistry, Aichi-Gakuin University, Nagoya, Aichi 464-8650, Japan
| | - Yoonsuk Park
- Department of Oral Biology, University of Florida, Gainesville, FL 32610, USA
| | - Kiyoshi Nishikawa
- Department of Microbiology, School of Dentistry, Aichi-Gakuin University, Nagoya, Aichi 464-8650, Japan
| | - Tatsuo Atsumi
- Department of Medical Technology, Gifu University of Medical Science, Seki, Gifu 501-3892, Japan.,Department of Microbiology, School of Dentistry, Aichi-Gakuin University, Nagoya, Aichi 464-8650, Japan
| | - Keiichi Moriguchi
- Department of Anatomy, School of Dentistry, Aichi-Gakuin University, Nagoya, Aichi 464-8650, Japan
| | - Yukitaka Murakami
- Department of Microbiology, School of Dentistry, Aichi-Gakuin University, Nagoya, Aichi 464-8650, Japan
| | - Richard J Lamont
- Department of Oral Biology, University of Florida, Gainesville, FL 32610, USA
| | - Hiroshi Nakamura
- Department of Endodontology, School of Dentistry, Aichi-Gakuin University, Nagoya, Aichi 464-8650, Japan
| | - Norikazu Ohno
- Department of Anatomy, School of Dentistry, Aichi-Gakuin University, Nagoya, Aichi 464-8650, Japan
| | - Fuminobu Yoshimura
- Department of Microbiology, School of Dentistry, Aichi-Gakuin University, Nagoya, Aichi 464-8650, Japan
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42
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Lo AW, Seers CA, Boyce JD, Dashper SG, Slakeski N, Lissel JP, Reynolds EC. Comparative transcriptomic analysis of Porphyromonas gingivalis biofilm and planktonic cells. BMC Microbiol 2009; 9:18. [PMID: 19175941 PMCID: PMC2637884 DOI: 10.1186/1471-2180-9-18] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2008] [Accepted: 01/29/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Porphyromonas gingivalis in subgingival dental plaque, as part of a mature biofilm, has been strongly implicated in the onset and progression of chronic periodontitis. In this study using DNA microarray we compared the global gene expression of a P. gingivalis biofilm with that of its planktonic counterpart grown in the same continuous culture. RESULTS Approximately 18% (377 genes, at 1.5 fold or more, P-value < 0.01) of the P. gingivalis genome was differentially expressed when the bacterium was grown as a biofilm. Genes that were down-regulated in biofilm cells, relative to planktonic cells, included those involved in cell envelope biogenesis, DNA replication, energy production and biosynthesis of cofactors, prosthetic groups and carriers. A number of genes encoding transport and binding proteins were up-regulated in P. gingivalis biofilm cells. Several genes predicted to encode proteins involved in signal transduction and transcriptional regulation were differentially regulated and may be important in the regulation of biofilm growth. CONCLUSION This study analyzing global gene expression provides insight into the adaptive response of P. gingivalis to biofilm growth, in particular showing a down regulation of genes involved in growth and metabolic activity.
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Affiliation(s)
- Alvin W Lo
- Cooperative Research Centre for Oral Health Science, Melbourne Dental School and the Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia.
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43
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Regulation of hemin binding proteins by a novel transcriptional activator in Porphyromonas gingivalis. J Bacteriol 2008; 191:115-22. [PMID: 18931136 DOI: 10.1128/jb.00841-08] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
One of the features of the periodontal pathogen Porphyromonas gingivalis is the presence of complex iron acquisition systems that include an hmuYRSTUV locus. HmuY and HmuR are hemin binding proteins required for P. gingivalis growth. Previous studies have demonstrated that expression of the hmu locus is regulated in response to environmental changes, such as growth phases. However, the mechanisms involved in hmu gene regulation are poorly understood. Here we report that a novel transcriptional activator, PG1237, is required for the expression of humY and humR, but not other iron acquisition-related genes, such as fetB and tlr, which also encode hemin binding proteins. Real-time reverse transcription-PCR analysis revealed that a mutation in the pg1237 gene decreased expression of hmuY and hmuR 149- and 25-fold, respectively, compared to that observed in the wild-type strain. In addition, differential expression of hmuY, hmuR, and the pg1237 gene was found to be quorum-sensing dependent, such that higher expression levels of these genes were observed when P. gingivalis was grown at a lower cell density, such as that seen during the early exponential growth phase. This work demonstrates the involvement of a novel transcriptional activator, PG1237, in expression of the hmu operon in a cell density-dependent fashion.
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Yoshimura F, Murakami Y, Nishikawa K, Hasegawa Y, Kawaminami S. Surface components of Porphyromonas gingivalis. J Periodontal Res 2008; 44:1-12. [PMID: 18973529 DOI: 10.1111/j.1600-0765.2008.01135.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND AND OBJECTIVE Research on Porphyromonas gingivalis, a periodontopathogen, has provided a tremendous amount of information over the last 20 years, which may exceed in part than that on other closely related members in terms of phylogenetic as well as proteomic criteria, including Bacteroides fragilis and B. thetaiotaomicron as major anaerobic, opportunistic pathogens in the medical field. In this minireview, we focused on recent research findings concerning surface components such as outer membrane proteins and fimbriae, of P. gingivalis. MATERIAL AND METHODS Elucidation of the surface components in P. gingivalis was especially difficult because outer membrane proteins are tightly bound to lipopolysaccharide and they are resistant to dissociation and separation from each other, even during sodium dodecyl sulfate-polyacrylamide gel electrophoresis, unless samples are appropriately heated. In addition, P. gingivalis is asaccharolytic and therefore a potent proteolytic bacterium, another factor causing difficulty in research. The study of the surface components was carefully carried out considering these unique features in P. gingivalis when compared with other gram-negative bacteria, including Escherichia coli and Pseudomonas aeruginosa. RESULTS Separation of outer membrane proteins, and characterization of OmpA-like proteins and RagAB as major proteins, is described herein. Our recent findings on FimA and Mfa1 fimbriae, two unique appendages in this organism, and on their regulation of expression are also described briefly. CONCLUSION Surface components of P. gingivalis somehow have contact with host tissues and cells because of the outermost cell elements. Therefore, such bacterial components are potentially important in the occurrence of periodontal diseases.
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Affiliation(s)
- F Yoshimura
- Department of Microbiology, School of Dentistry, Aichi-Gakuin University, Nagoya, Aichi, Japan.
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45
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Boisvert H, Duncan MJ. Clathrin-dependent entry of a gingipain adhesin peptide and Porphyromonas gingivalis into host cells. Cell Microbiol 2008; 10:2538-52. [PMID: 18717820 DOI: 10.1111/j.1462-5822.2008.01228.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Porphyromonas gingivalis, a Gram-negative oral anaerobe, is associated with periodontitis, a disease that in some form affects up to 80% of the adult population in the USA. The organism interacts with gingival epithelium and surrounding tissue, and in this study we analysed interactions initiated by P. gingivalis and by a peptide derived from the adhesin domain of arg-gingipain A, a member of a family of surface cysteine proteinases. Recombinant peptide A44 blocked adherence of bacteria to host cell monolayers, and bound to components of the cell membrane fraction. In pull-down assays A44 associated with proteins involved in a clathrin-dependent endocytosis pathway. Inhibitor studies confirmed a role for clathrin, and confocal microscopy demonstrated that both A44-coated beads and intact bacteria colocalized with GFP-clathrin in host cells. Finally, we used siRNA to determine whether clathrin or caveolin-1 was involved in association of peptide and intact bacteria with host cells. Again, the results of these assays indicated that association of both A44 and P. gingivalis depended on the presence of clathrin, and support a working model in which A44 initiates a clathrin-dependent pathway that potentially leads to internalization of peptide or bacteria by host epithelial cells.
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Affiliation(s)
- Heike Boisvert
- Department of Molecular Genetics, The Forsyth Institute, Boston, MA 02115, USA
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46
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Wu J, Lin X, Xie H. OxyR is involved in coordinate regulation of expression of fimA and sod genes in Porphyromonas gingivalis. FEMS Microbiol Lett 2008; 282:188-95. [PMID: 18355277 PMCID: PMC2430334 DOI: 10.1111/j.1574-6968.2008.01116.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Survival of Porphyromonas gingivalis in the constantly changing oral environment depends on its ability to alter gene expression. We demonstrate here that P. gingivalis activates superoxide dismutase expression in response to oxidative stress and represses expression of FimA, a subunit of major fimbriae. Coordinated expression of fimA and sod is regulated by the redox-sensing transcription factor OxyR. Mutations in the oxyR gene result in a decreased expression of sod and in an elevated expression of fimA. In addition, we provide evidence that regulation of expression of fimA and sod by OxyR is mediated by direct interaction of OxyR and the promoters of these two genes. These results suggest that OxyR plays an important role in regulation of expression of virulence genes in P. gingivalis.
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Affiliation(s)
- Jie Wu
- School of Dentistry, Meharry Medical College, Nashville, TN 37208, USA
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47
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Abstract
Porphyromonas gingivalis is a Gram-negative oral anaerobe associated with chronic adult periodontitis. Its ecological niche is the gingival crevice, where the organism adapts to the challenges of the infectious process such as host defence and bacterial products. Bacterial responses to environmental changes are partly regulated by two-component signal transduction systems. Several intact systems were annotated in the genome of P. gingivalis, as well as an orphan regulator encoding a homologue of RprY, a response regulator from Bacteroides fragilis. With the goal of defining the environmental cues that activate RprY in P. gingivalis, we used several strategies to identify its regulon. Results from gene expression and DNA-protein binding assays identified target genes that were either involved in transport functions or associated with oxidative stress, and indicated that RprY can act as an activator and a repressor. RprY positively activated the primary sodium pump, NADH : ubiquinone oxidoreductase (NQR), and RprY protein also interacted with the promoter regions of nqrA genes from B. fragilis and Vibrio cholerae. Given that gingival bleeding and infiltration of host defence cells are symptoms of periodontal infection, iron products released from blood and reactive oxygen species from polymorphonuclear leucocytes may be potential inducers of the RprY regulon.
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Affiliation(s)
- Ana E Duran-Pinedo
- Department of Molecular Genetics, Forsyth Institute, Boston, MA 02115, USA
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48
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Nishiyama SI, Murakami Y, Nagata H, Shizukuishi S, Kawagishi I, Yoshimura F. Involvement of minor components associated with the FimA fimbriae of Porphyromonas gingivalis in adhesive functions. MICROBIOLOGY-SGM 2007; 153:1916-1925. [PMID: 17526848 DOI: 10.1099/mic.0.2006/005561-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The FimA fimbriae of Porphyromonas gingivalis, the causative agent of periodontitis, have been implicated in various aspects of pathogenicity, such as colonization, adhesion and aggregation. In this study, the four open reading frames (ORF1, ORF2, ORF3 and ORF4) downstream of the fimbrilin gene (fimA) in strain ATCC 33277 were examined. ORF2, ORF3 and ORF4 were demonstrated to encode minor components of the fimbriae and were therefore renamed fimC, fimD and fimE, respectively. Immunoblotting analyses revealed that inactivation of either fimC or fimD by an ermF-ermAM insertion, but not inactivation of ORF1, was accompanied by concomitant loss of the products from the downstream genes, raising the possibility that fimC, fimD and fimE constitute a transcription unit. The fimE mutant produced FimC and FimD, but fimbriae purified from it contained neither protein, suggesting that FimE is required for the assembly of FimC and FimD onto the fimbrilin (FimA) fibre. The fimC, fimD and fimE mutants lost autoaggregation abilities. Fimbriae purified from these three mutants showed attenuated binding activities to glyceraldehyde-3-phosphate dehydrogenase of Streptococcus oralis and to two extracellular matrix proteins, fibronectin and type I collagen. These results suggest that FimE, as well as FimC and FimD, play critical roles in the adhesive activities of the mature FimA fimbriae in P. gingivalis.
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Affiliation(s)
- So-Ichiro Nishiyama
- Department of Microbiology, School of Dentistry, Aichi-Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya, Aichi 464-8650, Japan
| | - Yukitaka Murakami
- Department of Microbiology, School of Dentistry, Aichi-Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya, Aichi 464-8650, Japan
| | - Hideki Nagata
- Department of Preventive Dentistry, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Satoshi Shizukuishi
- Department of Preventive Dentistry, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Ikuro Kawagishi
- Department of Biological Science, Graduate School of Science and Institute for Advanced Research, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Fuminobu Yoshimura
- Department of Microbiology, School of Dentistry, Aichi-Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya, Aichi 464-8650, Japan
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49
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Wang M, Shakhatreh MAK, James D, Liang S, Nishiyama SI, Yoshimura F, Demuth DR, Hajishengallis G. Fimbrial proteins of porphyromonas gingivalis mediate in vivo virulence and exploit TLR2 and complement receptor 3 to persist in macrophages. THE JOURNAL OF IMMUNOLOGY 2007; 179:2349-58. [PMID: 17675496 DOI: 10.4049/jimmunol.179.4.2349] [Citation(s) in RCA: 149] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Porphyromonas gingivalis is an oral/systemic pathogen implicated in chronic conditions, although the mechanism(s) whereby it resists immune defenses and persists in the host is poorly understood. The virulence of this pathogen partially depends upon expression of fimbriae comprising polymerized fimbrillin (FimA) associated with quantitatively minor proteins (FimCDE). In this study, we show that isogenic mutants lacking FimCDE are dramatically less persistent and virulent in a mouse periodontitis model and express shorter fimbriae than the wild type. Strikingly, native fimbriae allowed P. gingivalis to exploit the TLR2/complement receptor 3 pathway for intracellular entry, inhibition of IL-12p70, and persistence in macrophages. This virulence mechanism also required FimCDE; indeed, mutant strains exhibited significantly reduced ability to inhibit IL-12p70, invade, and persist intracellularly, attributable to failure to interact with complement receptor 3, although not with TLR2. These results highlight a hitherto unknown mechanism of immune evasion by P. gingivalis that is surprisingly dependent upon minor constituents of its fimbriae, and support the concept that pathogens evolved to manipulate innate immunity for promoting adaptive fitness and thus their capacity to cause disease.
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MESH Headings
- Adaptation, Biological/genetics
- Adaptation, Biological/immunology
- Animals
- Bacterial Proteins/immunology
- Bacteroidaceae Infections/genetics
- Bacteroidaceae Infections/immunology
- Bacteroidaceae Infections/pathology
- Biological Evolution
- CD11b Antigen/genetics
- CD11b Antigen/immunology
- Cells, Cultured
- Chronic Disease
- Disease Models, Animal
- Fimbriae Proteins/deficiency
- Fimbriae Proteins/genetics
- Fimbriae Proteins/immunology
- Immunity, Innate/genetics
- Interleukin-12/genetics
- Interleukin-12/immunology
- Macrophages, Peritoneal/immunology
- Macrophages, Peritoneal/microbiology
- Macrophages, Peritoneal/pathology
- Mice
- Mice, Knockout
- Periodontitis/genetics
- Periodontitis/immunology
- Periodontitis/pathology
- Porphyromonas gingivalis/genetics
- Porphyromonas gingivalis/immunology
- Porphyromonas gingivalis/pathogenicity
- Receptors, Complement/deficiency
- Receptors, Complement/immunology
- Toll-Like Receptor 2/deficiency
- Toll-Like Receptor 2/immunology
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Affiliation(s)
- Min Wang
- Department of Periodontics/Oral Health and Systemic Disease, University of Louisville Health Sciences Center, Louisville, KY 40292, USA
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50
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Park Y, Xie H, Lamont RJ. Transcriptional organization of the Porphyromonas gingivalis fimA locus. FEMS Microbiol Lett 2007; 273:103-8. [PMID: 17559391 DOI: 10.1111/j.1574-6968.2007.00782.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Two different transcriptional start sites, as well as promoter regions and translational starts, have been proposed for the fimA gene encoding a long fimbriae subunit protein of Porphyromonas gingivalis. In this study, the fimA promoter regions and organization of the fimA operon were characterized. The two putative promoter regions for fimA were fused with a lacZ reporter gene, cloned into the shuttle plasmid vector pT-COW, and the recombinant plasmids were introduced to P. gingivalis 33277. Reverse transcriptase-polymerase chain reaction demonstrated mRNA production from the promoter proximal to the translational start. LacZ activities of P. gingivalis containing the recombinant plasmids showed that maximal expression of fimA was promoted by the proximal promoter in combination with distal regulatory sequences. A polycistronic message spanning PG2130, PG2131 and fimA (PG2132) was observed, thus fimA transcripts may also be generated by processing of the polycistronic message.
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Affiliation(s)
- Yoonsuk Park
- Department of Oral Biology, University of Florida, Gainesville, FL 32610, USA.
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