1
|
Elashiry M, Carroll A, Yuan J, Liu Y, Hamrick M, Cutler CW, Wang Q, Elsayed R. Oral Microbially-Induced Small Extracellular Vesicles Cross the Blood-Brain Barrier. Int J Mol Sci 2024; 25:4509. [PMID: 38674094 PMCID: PMC11049816 DOI: 10.3390/ijms25084509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/08/2024] [Accepted: 04/14/2024] [Indexed: 04/28/2024] Open
Abstract
Porphyromonas gingivalis (Pg) and its gingipain proteases contribute to Alzheimer's disease (AD) pathogenesis through yet unclear mechanisms. Cellular secretion of small extracellular vesicles or exosomes (EXO) increases with aging as part of the senescence-associated secretory phenotype (SASP). We have shown that EXO isolated from Pg-infected dendritic cells contain gingipains and other Pg antigens and transmit senescence to bystander gingival cells, inducing alveolar bone loss in mice in vivo. Here, EXO were isolated from the gingiva of mice and humans with/without periodontitis (PD) to determine their ability to penetrate the blood-brain barrier (BBB) in vitro and in vivo. PD was induced by Pg oral gavage for 6 weeks in C57B6 mice. EXO isolated from the gingiva or brain of donor Pg-infected (PD EXO) or control animals (Con EXO) were characterized by NTA, Western blot, and TEM. Gingival PD EXO or Con EXO were labeled and injected into the gingiva of uninfected WT mouse model. EXO biodistribution in brains was tracked by an in vivo imaging system (IVIS) and confocal microscopy. The effect of human PD EXO on BBB integrity and permeability was examined using TEER and FITC dextran assays in a human in vitro 3D model of the BBB. Pg antigens (RGP and Mfa-1) were detected in EXO derived from gingival and brain tissues of donor Pg-infected mice. Orally injected PD EXO from donor mice penetrated the brains of recipient uninfected mice and colocalized with hippocampal microglial cells. IL-1β and IL-6 were expressed in human PD EXO and not in Con EXO. Human PD EXO promoted BBB permeability and penetrated the BBB in vitro. This is the first demonstration that microbial-induced EXO in the oral cavity can disseminate, cross the BBB, and may contribute to AD pathogenesis.
Collapse
Affiliation(s)
- Mahmoud Elashiry
- Department of Periodontics, Dental College of Georgia, Augusta University, Augusta, GA 30912, USA; (M.E.); (A.C.); (J.Y.); (C.W.C.)
| | - Angelica Carroll
- Department of Periodontics, Dental College of Georgia, Augusta University, Augusta, GA 30912, USA; (M.E.); (A.C.); (J.Y.); (C.W.C.)
| | - Jessie Yuan
- Department of Periodontics, Dental College of Georgia, Augusta University, Augusta, GA 30912, USA; (M.E.); (A.C.); (J.Y.); (C.W.C.)
| | - Yutao Liu
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA; (Y.L.); (M.H.)
| | - Mark Hamrick
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA; (Y.L.); (M.H.)
| | - Christopher W. Cutler
- Department of Periodontics, Dental College of Georgia, Augusta University, Augusta, GA 30912, USA; (M.E.); (A.C.); (J.Y.); (C.W.C.)
| | - Qin Wang
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA;
| | - Ranya Elsayed
- Department of Periodontics, Dental College of Georgia, Augusta University, Augusta, GA 30912, USA; (M.E.); (A.C.); (J.Y.); (C.W.C.)
| |
Collapse
|
2
|
Pham C, Guo S, Han X, Coleman L, Sze CW, Wang H, Liu J, Li C. A pleiotropic role of sialidase in the pathogenicity of Porphyromonas gingivalis. Infect Immun 2024; 92:e0034423. [PMID: 38376159 PMCID: PMC10929438 DOI: 10.1128/iai.00344-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 02/01/2024] [Indexed: 02/21/2024] Open
Abstract
As one of the keystone pathogens of periodontitis, the oral bacterium Porphyromonas gingivalis produces an array of virulence factors, including a recently identified sialidase (PG0352). Our previous report involving loss-of-function studies indicated that PG0352 plays an important role in the pathophysiology of P. gingivalis. However, this report had not been corroborated by gain-of-function studies or substantiated in different P. gingivalis strains. To fill these gaps, herein we first confirm the role of PG0352 in cell surface structures (e.g., capsule) and serum resistance using P. gingivalis W83 strain through genetic complementation and then recapitulate these studies using P. gingivalis ATCC33277 strain. We further investigate the role of PG0352 and its counterpart (PGN1608) in ATCC33277 in cell growth, biofilm formation, neutrophil killing, cell invasion, and P. gingivalis-induced inflammation. Our results indicate that PG0352 and PGN1608 are implicated in P. gingivalis cell surface structures, hydrophobicity, biofilm formation, resistance to complement and neutrophil killing, and host immune responses. Possible molecular mechanisms involved are also discussed. In summary, this report underscores the importance of sialidases in the pathophysiology of P. gingivalis and opens an avenue to elucidate their underlying molecular mechanisms.
Collapse
Affiliation(s)
- Christopher Pham
- Department of Oral Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Shuaiqi Guo
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
- Microbial Sciences Institute, Yale University, West Haven, Connecticut, USA
| | - Xiao Han
- Department of Oral Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Laurynn Coleman
- Department of Oral Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Ching Wooen Sze
- Department of Oral Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Huizhi Wang
- Department of Oral Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Jun Liu
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
- Microbial Sciences Institute, Yale University, West Haven, Connecticut, USA
| | - Chunhao Li
- Department of Oral Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, USA
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia, USA
| |
Collapse
|
3
|
Meghil MM, Cutler CW. Influence of Vitamin D on Periodontal Inflammation: A Review. Pathogens 2023; 12:1180. [PMID: 37764988 PMCID: PMC10537363 DOI: 10.3390/pathogens12091180] [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: 08/09/2023] [Revised: 09/09/2023] [Accepted: 09/18/2023] [Indexed: 09/29/2023] Open
Abstract
The active form of vitamin D is the hormonally active 1,25(OH)2D3 (Vit D) vitamin, which plays an important role in bone biology and host immunity. The vitamin D receptor (VDR) is a nuclear ligand-dependent transcription factor expressed by many cells. Ligation of VDR by VitD regulates a wide plethora of genes and physiologic functions through the formation of the complex Vit D-VDR signaling cascade. The influence of Vit D-VDR signaling in host immune response to microbial infection has been of interest to many researchers. This is particularly important in oral health and diseases, as oral mucosa is exposed to a complex microbiota, with certain species capable of causing disruption to immune homeostasis. In this review, we focus on the immune modulatory roles of Vit D in the bone degenerative oral disease, periodontitis.
Collapse
Affiliation(s)
- Mohamed M. Meghil
- Department of Periodontics, The Dental College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Christopher W. Cutler
- Department of Periodontics, The Dental College of Georgia, Augusta University, Augusta, GA 30912, USA
| |
Collapse
|
4
|
Fujimoto M, Naiki Y, Sakae K, Iwase T, Miwa N, Nagano K, Nawa H, Hasegawa Y. Structural and antigenic characterization of a novel genotype of Mfa1 fimbriae in Porphyromonas gingivalis. J Oral Microbiol 2023; 15:2215551. [PMID: 37223052 PMCID: PMC10201998 DOI: 10.1080/20002297.2023.2215551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 05/11/2023] [Accepted: 05/12/2023] [Indexed: 05/25/2023] Open
Abstract
Background Mfa1 fimbriae of the periodontal pathogen Porphyromonas gingivalis are responsible for biofilm formation and comprise five proteins: Mfa1-5. Two major genotypes, mfa170 and mfa153, encode major fimbrillin. The mfa170 genotype is further divided into the mfa170A and mfa170B subtypes. The properties of the novel mfa170B remain unclear. Methods Fimbriae were purified from P. gingivalis strains JI-1 (mfa170A), 1439 (mfa170B), and Ando (mfa153), and their components and their structures were analyzed. Protein expression and variability in the antigenic specificity of fimbrillins were compared using Coomassie staining and western blotting using polyclonal antibodies against Mfa170A, Mfa170B, and Mfa153 proteins. Cell surface expression levels of fimbriae were analyzed by filtration enzyme-linked immunosorbent assays. Results The composition and structures of the purified Mfa1 fimbriae of 1439 was similar to that of JI-1. However, each Mfa1 protein of differential subtype/genotype was specifically detected by western blotting. Mfa170B fimbriae were expressed in several strains such as 1439, JKG9, B42, 1436, and Kyudai-3. Differential protein expression and antigenic heterogeneities were detected in Mfa2-5 between strains. Conclusion Mfa1 fimbriae from the mfa170A and mfa170B genotypes indicated an antigenic difference suggesting the mfa170B, is to be utilized for the novel classification of P. gingivalis.
Collapse
Affiliation(s)
- Miyuna Fujimoto
- Department of Microbiology, School of Dentistry, Aichi Gakuin University, Nagoya, Japan
- Department of Pediatric Dentistry, School of Dentistry, Aichi Gakuin University, Nagoya, Japan
| | - Yoshikazu Naiki
- Department of Microbiology, School of Dentistry, Aichi Gakuin University, Nagoya, Japan
| | - Kotaro Sakae
- Department of Microbiology, School of Dentistry, Aichi Gakuin University, Nagoya, Japan
| | - Tomohiko Iwase
- Department of Microbiology, School of Dentistry, Aichi Gakuin University, Nagoya, Japan
| | - Naoyoshi Miwa
- Department of Pediatric Dentistry, School of Dentistry, Aichi Gakuin University, Nagoya, Japan
| | - Keiji Nagano
- Division of Microbiology, Department of Oral Biology, School of Dentistry, Health Sciences University of Hokkaido, Hokkaido, Japan
| | - Hiroyuki Nawa
- Department of Pediatric Dentistry, School of Dentistry, Aichi Gakuin University, Nagoya, Japan
| | - Yoshiaki Hasegawa
- Department of Microbiology, School of Dentistry, Aichi Gakuin University, Nagoya, Japan
| |
Collapse
|
5
|
He H, Hao Y, Fan Y, Li B, Cheng L. The interaction between innate immunity and oral microbiota in oral diseases. Expert Rev Clin Immunol 2023; 19:405-415. [PMID: 36803467 DOI: 10.1080/1744666x.2023.2182291] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
INTRODUCTION Innate immunity serves as the frontline to combat invading pathogens. Oral microbiota is the total collection of microorganisms colonized within the oral cavity. By recognizing the resident microorganisms through pattern recognition receptors, innate immunity is capable of interacting with oral microbiota and maintaining homeostasis. Dysregulation of interaction may lead to the pathogenesis of several oral diseases. Decoding the crosstalk between oral microbiota and innate immunity may be contributory to developing novel therapies for preventing and treating oral diseases. AREAS COVERED This article reviewed pattern recognition receptors in the recognition of oral microbiota, the reciprocal interaction between innate immunity and oral microbiota, and discussed how the dysregulation of this relationship leads to the pathogenesis and development of oral diseases. EXPERT OPINION Many studies have been conducted to illustrate the relationship between oral microbiota and innate immunity and its role in the occurrence of different oral diseases. The impact and mechanisms of innate immune cells on oral microbiota and the mechanisms of dysbiotic microbiota in altering innate immunity are still needed to be investigated. Altering the oral microbiota might be a possible solution for treating and preventing oral diseases.
Collapse
Affiliation(s)
- Hongzhi He
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu, Sichuan, China.,Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Yu Hao
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu, Sichuan, China.,Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Yu Fan
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu, Sichuan, China.,Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Bolei Li
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu, Sichuan, China.,Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Lei Cheng
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu, Sichuan, China.,Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| |
Collapse
|
6
|
Virulence Factors of the Periodontal Pathogens: Tools to Evade the Host Immune Response and Promote Carcinogenesis. Microorganisms 2023; 11:microorganisms11010115. [PMID: 36677408 PMCID: PMC9860638 DOI: 10.3390/microorganisms11010115] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/27/2022] [Accepted: 12/28/2022] [Indexed: 01/04/2023] Open
Abstract
Periodontitis is the most common chronic, inflammatory oral disease that affects more than half of the population in the United States. The disease leads to destruction of the tooth-supporting tissue called periodontium, which ultimately results in tooth loss if uncured. The interaction between the periodontal microbiota and the host immune cells result in the induction of a non-protective host immune response that triggers host tissue destruction. Certain pathogens have been implicated periodontal disease formation that is triggered by a plethora of virulence factors. There is a collective evidence on the impact of periodontal disease progression on systemic health. Of particular interest, the role of the virulence factors of the periodontal pathogens in facilitating the evasion of the host immune cells and promotion of carcinogenesis has been the focus of many researchers. The aim of this review is to examine the influence of the periodontal pathogens Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), Porphyromonas gingivalis (P. gingivalis), and Fusobacterium nucleatum (F. nucleatum) in the modulation of the intracellular signaling pathways of the host cells in order to evade the host immune response and interfere with normal host cell death and the role of their virulence factors in this regard.
Collapse
|
7
|
Glycosyltransferase-Related Protein GtrA Is Essential for Localization of Type IX Secretion System Cargo Protein Cellulase Cel9A and Affects Cellulose Degradation in Cytophaga hutchinsonii. Appl Environ Microbiol 2022; 88:e0107622. [PMID: 36197104 PMCID: PMC9599414 DOI: 10.1128/aem.01076-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Gram-negative bacterium Cytophaga hutchinsonii digests cellulose through a novel cellulose degradation mechanism. It possesses the lately characterized type IX secretion system (T9SS). We recently discovered that N-glycosylation of the C-terminal domain (CTD) of a hypothetical T9SS substrate protein in the periplasmic space of C. hutchinsonii affects protein secretion and localization. In this study, green fluorescent protein (GFP)-CTDCel9A recombinant protein was found with increased molecular weight in the periplasm of C. hutchinsonii. Site-directed mutagenesis studies on the CTD of cellulase Cel9A demonstrated that asparagine residue 900 in the D-X-N-X-S motif is important for the processing of the recombinant protein. We found that the glycosyltransferase-related protein GtrA (CHU_0012) located in the cytoplasm of C. hutchinsonii is essential for outer membrane localization of the recombinant protein. The deletion of gtrA decreased the abundance of the outer membrane proteins and affected cellulose degradation by C. hutchinsonii. This study provided a link between the glycosylation system and cellulose degradation in C. hutchinsonii. IMPORTANCE N-Glycosylation systems are generally limited to some pathogenic bacteria in prokaryotes. The disruption of the N-glycosylation pathway is related to adherence, invasion, colonization, and other phenotypic characteristics. We recently found that the cellulolytic bacterium Cytophaga hutchinsonii also has an N-glycosylation system. The cellulose degradation mechanism of C. hutchinsonii is novel and mysterious; cellulases and other proteins on the cell surface are involved in utilizing cellulose. In this study, we identified an asparagine residue in the C-terminal domain of cellulase Cel9A that is necessary for the processing of the T9SS cargo protein. Moreover, the glycosyltransferase-related protein GtrA is essential for the localization of the GFP-CTDCel9A recombinant protein. Deletion of gtrA affected cellulose degradation and the abundance of outer membrane proteins. This study enriched the understanding of the N-glycosylation system in C. hutchinsonii and provided a link between N-glycosylation and cellulose degradation, which also expanded the role of the N-glycosylation system in bacteria.
Collapse
|
8
|
Porphyromonas gingivalis Tyrosine Kinase Is a Fitness Determinant in Polymicrobial Infections. Infect Immun 2022; 90:e0017022. [PMID: 35575504 PMCID: PMC9202411 DOI: 10.1128/iai.00170-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Many pathogenic microbial ecosystems are polymicrobial, and community function can be shaped by interbacterial interactions. Little is known, however, regarding the genetic determinants required for fitness in heterotypic community environments. In periodontal diseases, Porphyromonas gingivalis is a primary pathogen, but only within polymicrobial communities. Here, we used a transposon sequencing (Tn-Seq) library of P. gingivalis to screen for genes that influence fitness of the organism in a coinfection murine abscess model with the oral partner species Streptococcus gordonii and Fusobacterium nucleatum. Genes impacting fitness with either organism were involved in diverse processes, including metabolism and energy production, along with cell wall and membrane biogenesis. Despite the overall similarity of function, the majority of identified genes were specific to the partner species, indicating that synergistic mechanisms of P. gingivalis vary to a large extent according to community composition. Only two genes were identified as essential for P. gingivalis fitness in abscess development with both S. gordonii and F. nucleatum: ptk1, encoding a tyrosine kinase, and inlJ, encoding an internalin family surface protein. Ptk1, but not InlJ, is required for community development with S. gordonii, and we found that the action of this kinase is similarly required for P. gingivalis to accumulate in a community with F. nucleatum. A limited number of P. gingivalis genes are therefore required for species-independent synergy, and the Ptk1 tyrosine kinase network may integrate and coordinate input from multiple organisms.
Collapse
|
9
|
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.
Collapse
|
10
|
El-Awady AR, Elashiry M, Morandini AC, Meghil MM, Cutler CW. Dendritic cells a critical link to alveolar bone loss and systemic disease risk in periodontitis: Immunotherapeutic implications. Periodontol 2000 2022; 89:41-50. [PMID: 35244951 DOI: 10.1111/prd.12428] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Extensive research in humans and animal models has begun to unravel the complex mechanisms that drive the immunopathogenesis of periodontitis. Neutrophils mount an early and rapid response to the subgingival oral microbiome, producing destructive enzymes to kill microbes. Chemokines and cytokines are released that attract macrophages, dendritic cells, and T cells to the site. Dendritic cells, the focus of this review, are professional antigen-presenting cells on the front line of immune surveillance. Dendritic cells consist of multiple subsets that reside in the epithelium, connective tissues, and major organs. Our work in humans and mice established that myeloid dendritic cells are mobilized in periodontitis. This occurs in lymphoid and nonlymphoid oral tissues, in the bloodstream, and in response to Porphyromonas gingivalis. Moreover, the dendritic cells mature in situ in gingival lamina propria, forming immune conjugates with cluster of differentiation (CD) 4+ T cells, called oral lymphoid foci. At such foci, the decisions are made as to whether to promote bone destructive T helper 17 or bone-sparing regulatory T cell responses. Interestingly, dendritic cells lack potent enzymes and reactive oxygen species needed to kill and degrade endocytosed microbes. The keystone pathogen P. gingivalis exploits this vulnerability by invading dendritic cells in the tissues and peripheral blood using its distinct fimbrial adhesins. This promotes pathogen dissemination and inflammatory disease at distant sites, such as atherosclerotic plaques. Interestingly, our recent studies indicate that such P. gingivalis-infected dendritic cells release nanosized extracellular vesicles called exosomes, in higher numbers than uninfected dendritic cells do. Secreted exosomes and inflammasome-related cytokines are a key feature of the senescence-associated secretory phenotype. Exosomes communicate in paracrine with neighboring stromal cells and immune cells to promote and amplify cellular senescence. We have shown that dendritic cell-derived exosomes can be custom tailored to target and reprogram specific immune cells responsible for inflammatory bone loss in mice. The long-term goal of these immunotherapeutic approaches, ongoing in our laboratory and others, is to promote human health and longevity.
Collapse
Affiliation(s)
- Ahmed R El-Awady
- Department of Periodontics, Dental College of Georgia at Augusta University, Augusta, Georgia, USA
| | - Mahmoud Elashiry
- Department of Periodontics, Dental College of Georgia at Augusta University, Augusta, Georgia, USA
| | - Ana C Morandini
- Department of Periodontics, Dental College of Georgia at Augusta University, Augusta, Georgia, USA.,Department of Oral Biology and Diagnostic Sciences, Dental College of Georgia at Augusta University, Augusta, Georgia, USA
| | - Mohamed M Meghil
- Department of Periodontics, Dental College of Georgia at Augusta University, Augusta, Georgia, USA
| | - Christopher W Cutler
- Department of Periodontics, Dental College of Georgia at Augusta University, Augusta, Georgia, USA
| |
Collapse
|
11
|
Abstract
Porphyromonas gingivalis is an important human pathogen and also a model organism for the Bacteroidetes phylum. O-glycosylation has been reported in this phylum with findings that include the O-glycosylation motif, the structure of the O-glycans in a few species, and an extensive O-glycoproteome analysis in Tannerella forsythia. However, O-glycosylation has not yet been confirmed in P. gingivalis. We therefore used glycoproteomics approaches including partial deglycosylation with trifluoromethanesulfonic acid as well as both HILIC and FAIMS based glycopeptide enrichment strategies leading to the identification of 257 putative glycosylation sites in 145 glycoproteins. The sequence of the major O-glycan was elucidated to be HexNAc-HexNAc(P-Gro-[Ac]0-2)-dHex-Hex-HexA-Hex(dHex). Western blot analyses of mutants lacking the glycosyltransferases PGN_1134 and PGN_1135 demonstrated their involvement in the biosynthesis of the glycan while mass spectrometry analysis of the truncated O-glycans suggested that PGN_1134 and PGN_1135 transfer the two HexNAc sugars. Interestingly, a strong bias against the O-glycosylation of abundant proteins exposed to the cell surface such as abundant T9SS cargo proteins, surface lipoproteins, and outer membrane β-barrel proteins was observed. In contrast, the great majority of proteins associated with the inner membrane or periplasm were glycosylated irrespective of their abundance. The P. gingivalis O-glycosylation system may therefore function to establish the desired physicochemical properties of the periplasm. IMPORTANCEPorphyromonas gingivalis is an oral pathogen primarily associated with severe periodontal disease and further associated with rheumatoid arthritis, dementia, cardiovascular disease, and certain cancers. Protein glycosylation can be important for a variety of reasons including protein function, solubility, protease resistance, and thermodynamic stability. This study has for the first time demonstrated the presence of O-linked glycosylation in this organism by determining the basic structure of the O-glycans and identifying 257 glycosylation sites in 145 proteins. It was found that most proteins exposed to the periplasm were O-glycosylated; however, the abundant surface exposed proteins were not. The O-glycans consisted of seven monosaccharides and a glycerol phosphate with 0–2 acetyl groups. These glycans are likely to have a stabilizing role to the proteins that bear them and must be taken into account when the proteins are produced in heterologous organisms.
Collapse
|
12
|
Elashiry M, Elsayed R, Cutler CW. Exogenous and Endogenous Dendritic Cell-Derived Exosomes: Lessons Learned for Immunotherapy and Disease Pathogenesis. Cells 2021; 11:cells11010115. [PMID: 35011677 PMCID: PMC8750541 DOI: 10.3390/cells11010115] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 12/22/2021] [Accepted: 12/23/2021] [Indexed: 12/12/2022] Open
Abstract
Immune therapeutic exosomes, derived exogenously from dendritic cells (DCs), the 'directors' of the immune response, are receiving favorable safety and tolerance profiles in phase I and II clinical trials for a growing number of inflammatory and neoplastic diseases. DC-derived exosomes (EXO), the focus of this review, can be custom tailored with immunoregulatory or immunostimulatory molecules for specific immune cell targeting. Moreover, the relative stability, small size and rapid uptake of EXO by recipient immune cells offer intriguing options for therapeutic purposes. This necessitates an in-depth understanding of mechanisms of EXO biogenesis, uptake and routing by recipient immune cells, as well as their in vivo biodistribution. Against this backdrop is recognition of endogenous exosomes, secreted by all cells, the molecular content of which is reflective of the metabolic state of these cells. In this regard, exosome biogenesis and secretion is regulated by cell stressors of chronic inflammation and tumorigenesis, including dysbiotic microbes, reactive oxygen species and DNA damage. Such cell stressors can promote premature senescence in young cells through the senescence associated secretory phenotype (SASP). Pathological exosomes of the SASP amplify inflammatory signaling in stressed cells in an autocrine fashion or promote inflammatory signaling to normal neighboring cells in paracrine, without the requirement of cell-to-cell contact. In summary, we review relevant lessons learned from the use of exogenous DC exosomes for immune therapy, as well as the pathogenic potential of endogenous DC exosomes.
Collapse
|
13
|
Hasegawa Y, Nagano K. Porphyromonas gingivalis FimA and Mfa1 fimbriae: Current insights on localization, function, biogenesis, and genotype. JAPANESE DENTAL SCIENCE REVIEW 2021; 57:190-200. [PMID: 34691295 PMCID: PMC8512630 DOI: 10.1016/j.jdsr.2021.09.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/16/2021] [Accepted: 09/21/2021] [Indexed: 11/16/2022] Open
Abstract
In general, the periodontal pathogen Porphyromonas gingivalis expresses distinct FimA and Mfa1 fimbriae. Each of these consists of five FimA–E and five Mfa1–5 proteins encoded by the fim and mfa gene clusters, respectively. The main shaft portion comprises FimA and Mfa1, whereas FimB and Mfa2 are localized on the basal portion and function as anchors and elongation terminators. FimC–E and Mfa3–5 participate in the assembly of an accessory protein complex on the tips of each fimbria. Hence, they serve as ligands for the receptors on host cells and other oral bacterial species. The crystal structures of FimA and Mfa1 fimbrial proteins were recently elucidated and new insights into the localization, function, and biogenesis of these proteins have been reported. Several studies indicated a correlation between P. gingivalis pathogenicity and the fimA genotype but not the mfa1 genotype. We recently revealed polymorphisms of all genes in the fim and mfa gene clusters. Intriguingly, mfa5 occurred in numerous different forms and underwent duplication. Detailed structural and functional knowledge of the fimbrial proteins in the context of the entire filament could facilitate the development of innovative therapeutic strategies for structure-based drug design.
Collapse
Affiliation(s)
- Yoshiaki Hasegawa
- Department of Microbiology, School of Dentistry, Aichi Gakuin University, Nagoya, Japan
| | - Keiji Nagano
- Division of Microbiology, Department of Oral Biology, School of Dentistry, Health Sciences University of Hokkaido, Hokkaido, Japan
| |
Collapse
|
14
|
N-glycosylation of a cargo protein C-terminal domain recognized by the type IX secretion system in Cytophaga hutchinsonii affects protein secretion and localization. Appl Environ Microbiol 2021; 88:e0160621. [PMID: 34644163 DOI: 10.1128/aem.01606-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cytophaga hutchinsonii is a Gram-negative bacterium belonging to the phylum Bacteroidetes. It digests crystalline cellulose with an unknown mechanism, and possesses a type IX secretion system (T9SS) that can recognize the C-terminal domain (CTD) of the cargo protein as a signal. In this study, the functions of CTD in the secretion and localization of T9SS substrates in C. hutchinsonii were studied by fusing the green fluorescent protein (GFP) with CTD from CHU_2708. CTD is necessary for the secretion of GFP by C. hutchinsonii T9SS. The GFP-CTDCHU_2708 fusion protein was found to be glycosylated in the periplasm with a molecular mass about 5 kDa higher than that predicted from its sequence. The glycosylated protein was sensitive to peptide-N-glycosidase F which can hydrolyze N-linked oligosaccharides. Analyses of mutants obtained by site-directed mutagenesis of asparagine residues in the N-X-S/T motif of CTDCHU_2708 suggest that N-glycosylation occurred on the CTD. CTD N-glycosylation is important for the secretion and localization of GFP-CTD recombinant proteins in C. hutchinsonii. Glycosyltransferase encoding gene chu_3842, a homologous gene of Campylobacter jejuni pglA, was found to participate in the N-glycosylation of C. hutchinsonii. Deletion of chu_3842 affected cell motility, cellulose degradation, and cell resistance to some chemicals. Our study provided the evidence that CTD as the signal of T9SS was N-glycosylated in the periplasm of C. hutchinsonii. IMPORTANCE The bacterial N-glycosylation system has previously only been found in several species of Proteobacteria and Campylobacterota, and the role of N-linked glycans in bacteria is still not fully understood. C. hutchinsonii has a unique cell-contact cellulose degradation mechanism, and many cell surface proteins including cellulases are secreted by the T9SS. Here, we found that C. hutchinsonii, a member of the phylum Bacteroidetes, has an N-glycosylation system. Glycosyltransferase CHU_3842 was found to participate in the N-glycosylation of C. hutchinsonii proteins, and had effects on cell resistance to some chemicals, cell motility, and cellulose degradation. Moreover, N-glycosylation occurs on the CTD translocation signal of T9SS. The glycosylation of CTD apears to play an important role in affecting T9SS substrates transportation and localization. This study enriched our understanding of the widespread existence and multiple biological roles of N-glycosylation in bacteria.
Collapse
|
15
|
Potempa J, Madej M, Scott DA. The RagA and RagB proteins of Porphyromonas gingivalis. Mol Oral Microbiol 2021; 36:225-232. [PMID: 34032024 DOI: 10.1111/omi.12345] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 05/05/2021] [Accepted: 05/07/2021] [Indexed: 11/27/2022]
Abstract
RagA and RagB proteins are major components of the outer membrane of the oral pathogen Porphyromonas gingivalis and, while recently suggested to represent a novel peptide uptake system, their full function is still under investigation. Herein, we (a) discuss the evidence that the rag locus contributes to P. gingivalis virulence; (b) provide insight to Rag protein potential biological function in macromolecular transport and other aspects of bacterial physiology; (c) address the host response to Rag proteins which are immunodominant and immunomodulatory; and (d) review the potential of Rag-focused therapeutic strategies for the control of periodontal diseases.
Collapse
Affiliation(s)
- Jan Potempa
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry, Louisville, Kentucky, USA.,Faculty of Biochemistry, Biophysics and Biotechnology, Department of Microbiology, Jagiellonian University, Kraków, Poland
| | - Mariusz Madej
- Faculty of Biochemistry, Biophysics and Biotechnology, Department of Microbiology, Jagiellonian University, Kraków, Poland
| | - David A Scott
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry, Louisville, Kentucky, USA
| |
Collapse
|
16
|
Elsayed R, Elashiry M, Liu Y, El-Awady A, Hamrick M, Cutler CW. Porphyromonas gingivalis Provokes Exosome Secretion and Paracrine Immune Senescence in Bystander Dendritic Cells. Front Cell Infect Microbiol 2021; 11:669989. [PMID: 34141629 PMCID: PMC8204290 DOI: 10.3389/fcimb.2021.669989] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 05/11/2021] [Indexed: 12/13/2022] Open
Abstract
Periodontitis is a disease of ageing or inflammaging, and is comorbid with other more severe age-related chronic diseases. With advanced age comes an increase in accumulation of senescent cells that release soluble and insoluble pro-inflammatory factors collectively termed the senescence associated secretory phenotype (SASP). In the present report, we examined whether immune cells typical of those at the oral mucosa-microbe interface, are vulnerable to cellular senescence (CS) and the role of dysbiotic oral pathogen Porphyromonas gingivalis. Bone marrow-derived dendritic cells (DCs) from young (yDCs) and old (oDCs) mice were co-cultured in vitro with CS inducer doxorubicin or P.gingivalis (Pg), plus or minus senolytic agent rapamycin. CS profiling revealed elevated CS mediators SA-β-Gal, p16 INK4A, p53, and p21Waf1/Clip1 in oDCs, or yDCs in response to doxorubicin or P. gingivalis, reversible with rapamycin. Functional studies indicate impaired maturation function of oDCs, and yDC exposed to P. gingivalis; moreover, OVA-driven proliferation of CD4+ T cells from young OTII transgenic mice was impaired by oDCs or yDCs+Pg. The SASP of DCs, consisting of secreted exosomes and inflammasome-related cytokines was further analyzed. Exosomes of DCs cocultured with P. gingivalis (PgDCexo) were purified, quantitated and characterized. Though typical in terms of size, shape and phenotype, PgDCexo were 2-fold greater in number than control DCs, with several important distinctions. Namely, PgDCexo were enriched in age-related miRNAs, and miRNAs reported to disrupt immune homeostasis through negative regulation of apoptosis and autophagy functions. We further show that PgDCexo were enriched in P. gingivalis fimbrial adhesin protein mfa1 and in inflammasome related cytokines IL-1β, TNFα and IL-6. Functionally PgDCexo were readily endocytosed by recipient yDCs, amplifying functional impairment in maturation and ability to promote Ova-driven proliferation of OTII CD4+ T cells from young mice. In conclusion P. gingivalis induces premature (autocrine) senescence in DCs by direct cellular invasion and greatly amplifies senescence, in paracrine, of bystander DCs by secretion of inflammatory exosomes. The implications of this pathological pathway for periodontal disease in vivo is under investigation in mouse models.
Collapse
Affiliation(s)
- Ranya Elsayed
- Department of Periodontics, Dental College of Georgia, Augusta University, Augusta, GA, United States
| | - Mahmoud Elashiry
- Department of Periodontics, Dental College of Georgia, Augusta University, Augusta, GA, United States
| | - Yutao Liu
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta, GA, United States
| | - Ahmed El-Awady
- Department of Periodontics, Dental College of Georgia, Augusta University, Augusta, GA, United States
| | - Mark Hamrick
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta, GA, United States
| | - Christopher W. Cutler
- Department of Periodontics, Dental College of Georgia, Augusta University, Augusta, GA, United States,*Correspondence: Christopher W. Cutler,
| |
Collapse
|
17
|
Jakubovics NS, Goodman SD, Mashburn-Warren L, Stafford GP, Cieplik F. The dental plaque biofilm matrix. Periodontol 2000 2021; 86:32-56. [PMID: 33690911 PMCID: PMC9413593 DOI: 10.1111/prd.12361] [Citation(s) in RCA: 132] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
| | - Steven D Goodman
- Center for Microbial Pathogenesis, The Abigail Wexner Research Institute at Nationwide Children's Hospital, The Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Lauren Mashburn-Warren
- Center for Microbial Pathogenesis, The Abigail Wexner Research Institute at Nationwide Children's Hospital, The Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Graham P Stafford
- Integrated Biosciences, School of Clinical Dentistry, University of Sheffield, Sheffield, UK
| | - Fabian Cieplik
- Department of Conservative Dentistry and Periodontology, University Hospital Regensburg, Regensburg, Germany
| |
Collapse
|
18
|
Murakami Y, Nagano K, Hasegawa Y. Separation of Glycosylated OmpA-Like Proteins from Porphyromonas gingivalis and Tannerella forsythia. Methods Mol Biol 2021; 2210:143-155. [PMID: 32815135 DOI: 10.1007/978-1-0716-0939-2_14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
OmpA-like proteins located in the outer bacterial membrane are potential virulence factors from the major periodontal pathogens Porphyromonas gingivalis and Tannerella forsythia. Our previous studies have shown that OmpA-like proteins are glycosylated by O-linked N-acetylglucosamine (O-GlcNAc) and are strongly reactive to wheat germ agglutinin (WGA) lectin, which shows sugar specificity to GlcNAc. Utilizing this property, we have developed a separation method for OmpA-like proteins by affinity chromatography using WGA lectin-agarose. The purity of enriched native OmpA-like proteins were confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Coomassie Brilliant Blue (CBB) staining. More importantly, the purified OmpA-like proteins formed a unique trimeric structure keeping their bioactivity intact. In this chapter, we describe a detailed procedure to separate OmpA-like proteins, which may be used to further progress the biological studies of OmpA-like proteins.
Collapse
Affiliation(s)
- Yukitaka Murakami
- Department of Dental Basic Education (Biology), Asahi University School of Dentistry, Mizuho, Gifu, Japan.
| | - Keiji Nagano
- Division of Microbiology, Department of Oral Biology, School of Dentistry, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido, Japan
| | - Yoshiaki Hasegawa
- Department of Microbiology, School of Dentistry, Aichi Gakuin University, Nisshin, Aichi, Japan
| |
Collapse
|
19
|
Enterococcus faecalis Induces Differentiation of Immune-Aberrant Dendritic Cells from Murine Bone Marrow-Derived Stem Cells. Infect Immun 2020; 88:IAI.00338-20. [PMID: 32839187 DOI: 10.1128/iai.00338-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 08/19/2020] [Indexed: 12/13/2022] Open
Abstract
Enterococcus faecalis, long implicated in serious systemic infections and failure of root canal treatment, is a persistent inhabitant of oral periapical lesions. Dendritic cells (DCs) and other innate immune cells patrol the oral mucosa for infecting microbes. Dendritic cells are efficient at capturing microbes when immature, whereupon they can transform into potent antigen-presenting cells upon full maturation. Autophagy, a sophisticated intracellular process first described for elimination of damaged organelles, regulates DC maturation and other important immune functions of DCs. The present study examined how E. faecalis influences the differentiation of murine bone marrow-derived stem cells (BMSCs) into functional DCs in the presence of the cytokines granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4). Although the viability and differentiation of DCs were not affected by E. faecalis, expression of the autophagy-related proteins ATG7, Beclin1, and LC3bI/II were significantly suppressed in an mTOR-dependent manner. Ultrastructurally, E. faecalis was identified in single-membrane vacuoles, some of which were in the process of binary fission. Bacterium-containing autophagosomes were absent within the cytoplasm. Accessory molecules (major histocompatibility complex class II [MHC-II], CD80, and CD86) and anti-inflammatory cytokine (transforming growth factor β1 [TGF-β1]) were suppressed in E. faecalis-induced DCs, while IL-1β, tumor necrosis factor alpha (TNF-α), and IL-12 levels were upregulated. When pulsed with ovalbumin (OVA), the E. faecalis-induced DCs showed reduction in CD4+ OVA-specific OT-II T cell proliferation. It is concluded that E. faecalis promotes the differentiation of bone marrow stem cells into CD11c-positive DCs with aberrant immune functions while retaining the capability of proinflammatory cytokine induction.
Collapse
|
20
|
Meghil MM, Cutler CW. Oral Microbes and Mucosal Dendritic Cells, "Spark and Flame" of Local and Distant Inflammatory Diseases. Int J Mol Sci 2020; 21:E1643. [PMID: 32121251 PMCID: PMC7084622 DOI: 10.3390/ijms21051643] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 02/24/2020] [Accepted: 02/25/2020] [Indexed: 12/20/2022] Open
Abstract
Mucosal health and disease is mediated by a complex interplay between the microbiota ("spark") and the inflammatory response ("flame"). Pathobionts, a specific class of microbes, exemplified by the oral microbe Porphyromonas gingivalis, live mostly "under the radar" in their human hosts, in a cooperative relationship with the indigenous microbiota. Dendritic cells (DCs), mucosal immune sentinels, often remain undisturbed by such microbes and do not alert adaptive immunity to danger. At a certain tipping point of inflammation, an "awakening" of pathobionts occurs, wherein their active growth and virulence are stimulated, leading to a dysbiosis. Pathobiont becomes pathogen, and commensal becomes accessory pathogen. The local inflammatory outcome is the Th17-mediated degenerative bone disease, periodontitis (PD). In systemic circulation of PD subjects, inflammatory DCs expand, carrying an oral microbiome and promoting Treg and Th17 responses. At distant peripheral sites, comorbid diseases including atherosclerosis, Alzheimer's disease, macular degeneration, chronic kidney disease, and others are reportedly induced. This review will review the immunobiology of DCs, examine the complex interplay of microbes and DCs in the pathogenesis of PD and its comorbid inflammatory diseases, and discuss the role of apoptosis and autophagy in this regard. Overall, the pathophysiological mechanisms of DC-mediated chronic inflammation and tissue destruction will be summarized.
Collapse
Affiliation(s)
| | - Christopher W. Cutler
- Department of Periodontics, The Dental College of Georgia at Augusta University, Augusta, GA 30912, USA;
| |
Collapse
|
21
|
Roky M, Trent JO, Demuth DR. Identification of functional domains of the minor fimbrial antigen involved in the interaction of Porphyromonas gingivalis with oral streptococci. Mol Oral Microbiol 2020; 35:66-77. [PMID: 31994329 PMCID: PMC7078856 DOI: 10.1111/omi.12280] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/23/2020] [Accepted: 01/24/2020] [Indexed: 12/20/2022]
Abstract
Porphyromonas gingivalis is associated with chronic periodontitis and may initially colonize the oral cavity by adhering to streptococci. Adhesion to streptococci is driven by interaction of the minor fimbrial antigen (Mfa1) with streptococcal antigen I/II. We identified the region of antigen I/II required for this interaction and developed small molecule mimetics that inhibited P. gingivalis adherence. However, the functional motifs of Mfa1 involved in the interaction with antigen I/II remain uncharacterized. A series of N- and C-terminal peptide fragments of Mfa1 were expressed and tested for inhibition of P. gingivalis adherence to S. gordonii. This approach identified residues 225-400 of Mfa1 as essential for P. gingivalis adherence. Using the three-dimensional structure of Mfa1, a putative binding cleft was identified using SiteMap and five small molecule mimetics could dock in this site. Site-specific mutation of residues in the predicted cleft, including R240A, W275A, D321A and A357P inhibited the interaction of Mfa1 with streptococci, whereas mutation of residues not in the predicted cleft (V238A, I252F and ΔK253) had no effect. Complementation of an Mfa1-deficient P. gingivalis strain with wild-type mfa1 restored adherence to streptococci, whereas complementation with full-length mfa1 containing the R240A or A357P mutations did not restore adherence. The mutations did not affect polymerization of Mfa1, suggesting that the complemented strains produced intact minor fimbriae. These results identified specific residues and structural motifs required for the Mfa1-antigen I/II interaction and will facilitate the design of small molecule therapeutics to prevent P. gingivalis colonization of the oral cavity.
Collapse
Affiliation(s)
- Mohammad Roky
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry, Louisville, KY, USA.,Department of Microbiology and Immunology, University of Louisville School of Medicine, Louisville, KY, USA
| | - John O Trent
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY, USA
| | - Donald R Demuth
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry, Louisville, KY, USA.,Department of Microbiology and Immunology, University of Louisville School of Medicine, Louisville, KY, USA
| |
Collapse
|
22
|
Meghil MM, Tawfik OK, Elashiry M, Rajendran M, Arce RM, Fulton DJ, Schoenlein PV, Cutler CW. Disruption of Immune Homeostasis in Human Dendritic Cells via Regulation of Autophagy and Apoptosis by Porphyromonas gingivalis. Front Immunol 2019; 10:2286. [PMID: 31608069 PMCID: PMC6769118 DOI: 10.3389/fimmu.2019.02286] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 09/10/2019] [Indexed: 12/11/2022] Open
Abstract
As fundamental processes of immune homeostasis, autophagy, and apoptosis must be maintained to mitigate risk of chronic inflammation and autoimmune diseases. Periodontitis is a chronic inflammatory disease characterized by oral microbial dysbiosis, and dysregulation of dendritic cell (DC) and T cell responses. The aim of this study was to elucidate the underlying mechanisms by which the oral microbe Porphyromonas gingivalis (P. gingivalis) manipulates dendritic cell signaling to perturb both autophagy and apoptosis. Using a combination of Western blotting, flow cytometry, qRT-PCR and immunofluorescence analysis, we show a pivotal role for the minor (Mfa1) fimbriae of P. gingivalis in nuclear/cytoplasmic shuttling of Akt and FOXO1 in human monocyte-derived DCs. Mfa1-induced Akt nuclear localization and activation ultimately induced mTOR. Activation of the Akt/mTOR axis downregulated intracellular LC3II, also known as Atg8, required for autophagosome formation and maturation. Use of allosteric panAkt inhibitor MK2206 and mTOR inhibitor rapamycin confirmed the role of Akt/mTOR signaling in autophagy inhibition by P. gingivalis in DCs. Interestingly, this pathway was also linked to induction of the anti-apoptotic protein Bcl2, decreased caspase-3 cleavage and decreased expression of pro-apoptotic proteins Bax and Bim, thus promoting longevity of host DCs. Addition of ABT-199 peptide to disrupt the interaction of antiapoptotic Bcl2 and its proapoptotic partners BAK/BAX restored apoptotic death to P. gingivalis-infected DC cells. In summary, we have identified the underlying mechanism by which P. gingivalis promotes its own survival and that of its host DCs.
Collapse
Affiliation(s)
- Mohamed M Meghil
- Department of Periodontics, Dental College of Georgia at Augusta University, Augusta, GA, United States.,Department of Oral Biology and Diagnostic Sciences, Dental College of Georgia at Augusta University, Augusta, GA, United States
| | - Omnia K Tawfik
- Department of Periodontics, Dental College of Georgia at Augusta University, Augusta, GA, United States
| | - Mahmoud Elashiry
- Department of Periodontics, Dental College of Georgia at Augusta University, Augusta, GA, United States.,Department of Oral Biology and Diagnostic Sciences, Dental College of Georgia at Augusta University, Augusta, GA, United States
| | - Mythilypriya Rajendran
- Department of Periodontics, Dental College of Georgia at Augusta University, Augusta, GA, United States
| | - Roger M Arce
- Department of Periodontics, Dental College of Georgia at Augusta University, Augusta, GA, United States
| | - David J Fulton
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, GA, United States
| | - Patricia V Schoenlein
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States
| | - Christopher W Cutler
- Department of Periodontics, Dental College of Georgia at Augusta University, Augusta, GA, United States
| |
Collapse
|
23
|
Rabelo MDS, El-Awady A, Moura Foz A, Hisse Gomes G, Rajendran M, Meghil MM, Lowry S, Romito GA, Cutler CW, Susin C. Influence of T2DM and prediabetes on blood DC subsets and function in subjects with periodontitis. Oral Dis 2019; 25:2020-2029. [PMID: 31541516 DOI: 10.1111/odi.13200] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 09/06/2019] [Accepted: 09/13/2019] [Indexed: 01/25/2023]
Abstract
OBJECTIVE To compare the myeloid and plasmacytoid DC counts and maturation status among subjects with/without generalized periodontitis (GP) and type 2 diabetes mellitus (T2DM). METHODS The frequency and maturation status of myeloid and plasmacytoid blood DCs were analyzed by flow cytometry in four groups of 15 subjects: healthy controls, T2DM with generalized CP (T2DM + GP), prediabetes with GP (PD + GP), and normoglycemics with GP (NG + GP). RT-PCR was used to determine levels of Porphyromonas gingivalis in the oral biofilms and within panDCs. The role of exogenous glucose effects on differentiation and apoptosis of healthy human MoDCs was explored in vitro. RESULTS Relative to controls and to NG + GP, T2DM + GP showed significantly lower CD1c + and CD303 + DC counts, while CD141 + DCs were lower in T2DM + GP relative to controls. Blood DC maturation required for mobilization and immune responsiveness was not observed. A statistically significant trend was observed for P. gingivalis levels in the biofilms of groups as follows: controls <NG+GP < PD+GP < T2DM+GP. Moreover, significantly higher P. gingivalis levels were observed in blood DCs of NG + GP than controls, whereas no differences were observed between controls and PD + GP/T2DM + GP. In vitro differentiation of MoDCs was significantly decreased, and apoptosis was increased by physiologically relevant glucose levels. CONCLUSION Type 2 diabetes mellitus appears to inhibit important DC immune homeostatic functions, including expansion and bacterial scavenging, which might be mediated by hyperglycemia.
Collapse
Affiliation(s)
- Mariana de Sousa Rabelo
- Division of Periodontics, Department of Stomatology, School of Dentistry, University of São Paulo, São Paulo, Brazil.,Department of Periodontics, The Dental College of Georgia, Augusta University, Augusta, GA, USA
| | - Ahmed El-Awady
- Department of Periodontics, The Dental College of Georgia, Augusta University, Augusta, GA, USA
| | - Adriana Moura Foz
- Division of Periodontics, Department of Stomatology, School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Giovane Hisse Gomes
- Division of Periodontics, Department of Stomatology, School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Mythilpriya Rajendran
- Department of Periodontics, The Dental College of Georgia, Augusta University, Augusta, GA, USA
| | - Mohamed M Meghil
- Department of Periodontics, The Dental College of Georgia, Augusta University, Augusta, GA, USA
| | - Scott Lowry
- Department of Periodontics, The Dental College of Georgia, Augusta University, Augusta, GA, USA
| | - Giuseppe Alexandre Romito
- Division of Periodontics, Department of Stomatology, School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Christopher W Cutler
- Department of Periodontics, The Dental College of Georgia, Augusta University, Augusta, GA, USA
| | - Cristiano Susin
- Department of Periodontology, Adams School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| |
Collapse
|
24
|
Śmiga M, Stępień P, Olczak M, Olczak T. PgFur participates differentially in expression of virulence factors in more virulent A7436 and less virulent ATCC 33277 Porphyromonas gingivalis strains. BMC Microbiol 2019; 19:127. [PMID: 31185896 PMCID: PMC6558696 DOI: 10.1186/s12866-019-1511-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 06/04/2019] [Indexed: 12/19/2022] Open
Abstract
Background Porphyromonas gingivalis is considered a keystone pathogen responsible for chronic periodontitis. Although several virulence factors produced by this bacterium are quite well characterized, very little is known about regulatory mechanisms that allow different strains of P. gingivalis to efficiently survive in the hostile environment of the oral cavity, a typical habitat characterized by low iron and heme concentrations. The aim of this study was to characterize P. gingivalis Fur homolog (PgFur) in terms of its role in production of virulence factors in more (A7436) and less (ATCC 33277) virulent strains. Results Expression of a pgfur depends on the growth phase and iron/heme concentration. To better understand the role played by the PgFur protein in P. gingivalis virulence under low- and high-iron/heme conditions, a pgfur-deficient ATCC 33277 strain (TO16) was constructed and its phenotype compared with that of a pgfur A7436-derived mutant strain (TO6). In contrast to the TO6 strain, the TO16 strain did not differ in the growth rate and hemolytic activity compared with the ATCC 33277 strain. However, both mutant strains were more sensitive to oxidative stress and they demonstrated changes in the production of lysine- (Kgp) and arginine-specific (Rgp) gingipains. In contrast to the wild-type strains, TO6 and TO16 mutant strains produced larger amounts of HmuY protein under high iron/heme conditions. We also demonstrated differences in production of glycoconjugates between the A7436 and ATCC 33277 strains and we found evidence that PgFur protein might regulate glycosylation process. Moreover, we revealed that PgFur protein plays a role in interactions with other periodontopathogens and is important for P. gingivalis infection of THP-1-derived macrophages and survival inside the cells. Deletion of the pgfur gene influences expression of many transcription factors, including two not yet characterized transcription factors from the Crp/Fnr family. We also observed lower expression of the CRISPR/Cas genes. Conclusions We show here for the first time that inactivation of the pgfur gene exerts a different influence on the phenotype of the A7436 and ATCC 33277 strains. Our findings further support the hypothesis that PgFur regulates expression of genes encoding surface virulence factors and/or genes involved in their maturation. Electronic supplementary material The online version of this article (10.1186/s12866-019-1511-x) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Michał Śmiga
- Laboratory of Medical Biology, Faculty of Biotechnology, University of Wrocław, F. Joliot-Curie 14A St, 50-383, Wrocław, Poland
| | - Paulina Stępień
- Laboratory of Medical Biology, Faculty of Biotechnology, University of Wrocław, F. Joliot-Curie 14A St, 50-383, Wrocław, Poland
| | - Mariusz Olczak
- Laboratory of Medical Biology, Faculty of Biotechnology, University of Wrocław, F. Joliot-Curie 14A St, 50-383, Wrocław, Poland
| | - Teresa Olczak
- Laboratory of Medical Biology, Faculty of Biotechnology, University of Wrocław, F. Joliot-Curie 14A St, 50-383, Wrocław, Poland.
| |
Collapse
|
25
|
Rajendran M, Looney S, Singh N, Elashiry M, Meghil MM, El-Awady AR, Tawfik O, Susin C, Arce RM, Cutler CW. Systemic Antibiotic Therapy Reduces Circulating Inflammatory Dendritic Cells and Treg-Th17 Plasticity in Periodontitis. THE JOURNAL OF IMMUNOLOGY 2019; 202:2690-2699. [PMID: 30944162 DOI: 10.4049/jimmunol.1900046] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 03/05/2019] [Indexed: 01/08/2023]
Abstract
Periodontitis (PD) is a common dysbiotic inflammatory disease that leads to local bone deterioration and tooth loss. PD patients experience low-grade bacteremias with oral microbes implicated in the risk of heart disease, cancer, and kidney failure. Although Th17 effectors are vital to fighting infection, functional imbalance of Th17 effectors and regulatory T cells (Tregs) promote inflammatory diseases. In this study, we investigated, in a small pilot randomized clinical trial, whether expansion of inflammatory blood myeloid dendritic cells (DCs) and conversion of Tregs to Th17 cells could be modulated with antibiotics (AB) as part of initial therapy in PD patients. PD patients were randomly assigned to either 7 d of peroral metronidazole/amoxicillin AB treatment or no AB, along with standard care debridement and chlorhexidine mouthwash. 16s ribosomal RNA analysis of keystone pathogen Porphyromonas gingivalis and its consortium members Fusobacterium nucleatum and Streptococcus gordonii confirmed the presence of all three species in the reservoirs (subgingival pockets and blood DCs) of PD patients before treatment. Of the three species, P. gingivalis was reduced in both reservoirs 4-6 wk after therapy. Further, the frequency of CD1C+CCR6+ myeloid DCs and IL-1R1 expression on IL-17A+FOXP3+CD4+ T cells in PD patients were reduced to healthy control levels. The latter led to decreased IL-1β-stimulated Treg plasticity in PD patients and improvement in clinical measures of PD. Overall, we identified an important, albeit short-term, beneficial role of AB therapy in reducing inflammatory DCs and Treg-Th17 plasticity in humans with PD.
Collapse
Affiliation(s)
- Mythilypriya Rajendran
- Department of Periodontics, Dental College of Georgia at Augusta University, Augusta, GA 30912
| | - Stephen Looney
- Department of Biostatistics and Epidemiology, Medical College of Georgia, Augusta University, Augusta, GA 30912
| | - Nagendra Singh
- Department of Biochemistry and Molecular Biology, Augusta University, Augusta, GA 30912.,Cancer Research Center, Augusta University, Augusta, GA 30912
| | - Mahmoud Elashiry
- Department of Periodontics, Dental College of Georgia at Augusta University, Augusta, GA 30912
| | - Mohamed M Meghil
- Department of Periodontics, Dental College of Georgia at Augusta University, Augusta, GA 30912
| | - Ahmed R El-Awady
- Department of Research, Immunology Program, Children's Cancer Hospital, Cairo 57357, Egypt
| | - Omnia Tawfik
- Department of Oral Medicine and Periodontology, Cairo University, Cairo 12613, Egypt; and
| | - Cristiano Susin
- Department of Periodontology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Roger M Arce
- Department of Periodontics, Dental College of Georgia at Augusta University, Augusta, GA 30912
| | - Christopher W Cutler
- Department of Periodontics, Dental College of Georgia at Augusta University, Augusta, GA 30912;
| |
Collapse
|
26
|
Polymicrobial synergy within oral biofilm promotes invasion of dendritic cells and survival of consortia members. NPJ Biofilms Microbiomes 2019; 5:11. [PMID: 32179736 PMCID: PMC6423025 DOI: 10.1038/s41522-019-0084-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 02/21/2019] [Indexed: 12/12/2022] Open
Abstract
Years of human microbiome research have confirmed that microbes rarely live or function alone, favoring diverse communities. Yet most experimental host-pathogen studies employ single species models of infection. Here, the influence of three-species oral microbial consortium on growth, virulence, invasion and persistence in dendritic cells (DCs) was examined experimentally in human monocyte-derived dendritic cells (DCs) and in patients with periodontitis (PD). Cooperative biofilm formation by Streptococcus gordonii, Fusobacterium nucleatum and Porphyromonas gingivalis was documented in vitro using growth models and scanning electron microscopy. Analysis of growth rates by species-specific 16s rRNA probes revealed distinct, early advantages to consortium growth for S. gordonii and F. nucleatum with P. gingivalis, while P. gingivalis upregulated its short mfa1 fimbriae, leading to increased invasion of DCs. F. nucleatum was only taken up by DCs when in consortium with P. gingivalis. Mature consortium regressed DC maturation upon uptake, as determined by flow cytometry. Analysis of dental plaques of PD and healthy subjects by 16s rRNA confirmed oral colonization with consortium members, but DC hematogenous spread was limited to P. gingivalis and F. nucleatum. Expression of P. gingivalis mfa1 fimbriae was increased in dental plaques and hematogenous DCs of PD patients. P. gingivalis in the consortium correlated with an adverse clinical response in the gingiva of PD subjects. In conclusion, we have identified polymicrobial synergy in a three-species oral consortium that may have negative consequences for the host, including microbial dissemination and adverse peripheral inflammatory responses.
Collapse
|
27
|
Wu L, Gong T, Zhou X, Zeng J, Huang R, Wu Y, Li Y. Global analysis of lysine succinylome in the periodontal pathogen Porphyromonas gingivalis. Mol Oral Microbiol 2019; 34:74-83. [PMID: 30672658 DOI: 10.1111/omi.12255] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 12/22/2018] [Accepted: 01/21/2019] [Indexed: 02/05/2023]
Abstract
The gram-negative anaerobe Porphyromonas gingivalis is not only a keystone periodontal pathogen but also an emerging systemic pathogen. Although the newly discovered protein post-translational modification (PTM), lysine succinylation (Ksuc), appears to play an important role in modulating metabolic processes in bacteria, this PTM has not been investigated in P gingivalis. In this study, we used a highly sensitive proteomics approach combining affinity enrichment with high-resolution liquid chromatography coupled with tandem mass spectrometry to examine Ksuc in P gingivalis. In total, 345 Ksuc sites in 233 proteins were identified and determined to be involved in a variety of cellular processes. In the region surrounding Ksuc sites, lysine residues were drastically overrepresented and sequence motifs with succinyl-lysine flanked by a lysine at the +3 or +6 positions appear to be unique to this pathogen. Additionally, our results suggest a crosstalk between Ksuc and glycosylation, but the overlap between Ksuc and acetylation in P gingivalis is quite different from that observed in other organisms. Notably, Ksuc was observed in proteins associated with established virulence factors, including gingipains, fimbriae, RagB, and PorR. Moreover, products of the factors necessary for P gingivalis in vitro survival (18.5%) were found to be succinylated at lysine sites and the same was observed in products of fitness factors for P gingivalis survival in both abscess and epithelial cell colonization environments (12%). Collectively, these results suggest that Ksuc may be a new mechanism in modulating the virulence, adaptation, and fitness of P gingivalis.
Collapse
Affiliation(s)
- Leng Wu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China.,Department of Stomatology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, PR China
| | - Tao Gong
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China
| | - Jumei Zeng
- Department of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Ruijie Huang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China
| | - Yafei Wu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China
| | - Yuqing Li
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China
| |
Collapse
|
28
|
Arjunan P, Meghil MM, Pi W, Xu J, Lang L, El-Awady A, Sullivan W, Rajendran M, Rabelo MS, Wang T, Tawfik OK, Kunde-Ramamoorthy G, Singh N, Muthusamy T, Susin C, Teng Y, Arce RM, Cutler CW. Oral Pathobiont Activates Anti-Apoptotic Pathway, Promoting both Immune Suppression and Oncogenic Cell Proliferation. Sci Rep 2018; 8:16607. [PMID: 30413788 PMCID: PMC6226501 DOI: 10.1038/s41598-018-35126-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 10/30/2018] [Indexed: 12/25/2022] Open
Abstract
Chronic periodontitis (CP) is a microbial dysbiotic disease linked to increased risk of oral squamous cell carcinomas (OSCCs). To address the underlying mechanisms, mouse and human cell infection models and human biopsy samples were employed. We show that the ‘keystone’ pathogen Porphyromonas gingivalis, disrupts immune surveillance by generating myeloid-derived dendritic suppressor cells (MDDSCs) from monocytes. MDDSCs inhibit CTLs and induce FOXP3 + Tregs through an anti-apoptotic pathway. This pathway, involving pAKT1, pFOXO1, FOXP3, IDO1 and BIM, is activated in humans with CP and in mice orally infected with Mfa1 expressing P. gingivalis strains. Mechanistically, activation of this pathway, demonstrating FOXP3 as a direct FOXO1-target gene, was demonstrated by ChIP-assay in human CP gingiva. Expression of oncogenic but not tumor suppressor markers is consistent with tumor cell proliferation demonstrated in OSCC-P. gingivalis cocultures. Importantly, FimA + P. gingivalis strain MFI invades OSCCs, inducing inflammatory/angiogenic/oncogenic proteins stimulating OSCCs proliferation through CXCR4. Inhibition of CXCR4 abolished Pg-MFI-induced OSCCs proliferation and reduced expression of oncogenic proteins SDF-1/CXCR4, plus pAKT1-pFOXO1. Conclusively, P. gingivalis, through Mfa1 and FimA fimbriae, promotes immunosuppression and oncogenic cell proliferation, respectively, through a two-hit receptor-ligand process involving DC-SIGN+hi/CXCR4+hi, activating a pAKT+hipFOXO1+hiBIM−lowFOXP3+hi and IDO+hi- driven pathway, likely to impact the prognosis of oral cancers in patients with periodontitis.
Collapse
Affiliation(s)
- Pachiappan Arjunan
- Department of Periodontics, Dental College of Georgia, Augusta University, Augusta, Georgia, United States of America.
| | - Mohamed M Meghil
- Department of Periodontics, Dental College of Georgia, Augusta University, Augusta, Georgia, United States of America.,Department of Oral Biology, Augusta University, Augusta, Georgia, United States of America
| | - Wenhu Pi
- Department of Radiation Oncology, Indiana University, Indianapolis, Indiana, United States of America
| | - Jinxian Xu
- Department of Periodontics, Dental College of Georgia, Augusta University, Augusta, Georgia, United States of America
| | - Liwei Lang
- Department of Oral Biology, Augusta University, Augusta, Georgia, United States of America
| | - Ahmed El-Awady
- Department of Periodontics, Dental College of Georgia, Augusta University, Augusta, Georgia, United States of America
| | - William Sullivan
- Department of Energy, Joint Genome Institute, California, United States of America
| | - Mythilypriya Rajendran
- Department of Periodontics, Dental College of Georgia, Augusta University, Augusta, Georgia, United States of America
| | - Mariana Sousa Rabelo
- Department of Periodontics, Dental College of Georgia, Augusta University, Augusta, Georgia, United States of America.,Department of Periodontics, University of São Paulo, Sao Paulo, Brazil
| | - Tong Wang
- Department of Periodontics, Dental College of Georgia, Augusta University, Augusta, Georgia, United States of America
| | - Omnia K Tawfik
- Department of Periodontics, Dental College of Georgia, Augusta University, Augusta, Georgia, United States of America
| | | | - Nagendra Singh
- Department of Biochemistry & Molecular Biology, Cancer Research Center, Augusta University, Augusta, Georgia, United States of America
| | - Thangaraju Muthusamy
- Department of Biochemistry & Molecular Biology, Cancer Research Center, Augusta University, Augusta, Georgia, United States of America
| | - Cristiano Susin
- Department of Periodontics, Dental College of Georgia, Augusta University, Augusta, Georgia, United States of America
| | - Yong Teng
- Department of Oral Biology, Augusta University, Augusta, Georgia, United States of America
| | - Roger M Arce
- Department of Periodontics, Dental College of Georgia, Augusta University, Augusta, Georgia, United States of America
| | - Christopher W Cutler
- Department of Periodontics, Dental College of Georgia, Augusta University, Augusta, Georgia, United States of America.
| |
Collapse
|
29
|
Tyagi RK, Miles B, Parmar R, Garg NK, Dalai SK, Baban B, Cutler CW. Human IDO-competent, long-lived immunoregulatory dendritic cells induced by intracellular pathogen, and their fate in humanized mice. Sci Rep 2017; 7:41083. [PMID: 28198424 PMCID: PMC5309771 DOI: 10.1038/srep41083] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 12/08/2016] [Indexed: 02/06/2023] Open
Abstract
Targeting of myeloid-dendritic cell receptor DC-SIGN by numerous chronic infectious agents, including Porphyromonas gingivalis, is shown to drive-differentiation of monocytes into dysfunctional mDCs. These mDCs exhibit alterations of their fine-tuned homeostatic function and contribute to dysregulated immune-responses. Here, we utilize P. gingivalis mutant strains to show that pathogen-differentiated mDCs from primary human-monocytes display anti-apoptotic profile, exhibited by elevated phosphorylated-Foxo1, phosphorylated-Akt1, and decreased Bim-expression. This results in an overall inhibition of DC-apoptosis. Direct stimulation of complex component CD40 on DCs leads to activation of Akt1, suggesting CD40 involvement in anti-apoptotic effects observed. Further, these DCs drove dampened CD8+ T-cell and Th1/Th17 effector-responses while inducing CD25+Foxp3+CD127- Tregs. In vitro Treg induction was mediated by DC expression of indoleamine 2,3-dioxygenase, and was confirmed in IDO-KO mouse model. Pathogen-infected &CMFDA-labeled MoDCs long-lasting survival was confirmed in a huMoDC reconstituted humanized mice. In conclusion, our data implicate PDDCs as an important target for resolution of chronic infection.
Collapse
MESH Headings
- Animals
- Apoptosis
- Bcl-2-Like Protein 11/metabolism
- CD40 Antigens/metabolism
- CD8-Positive T-Lymphocytes/cytology
- CD8-Positive T-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/metabolism
- Cell Differentiation
- Cytokines/metabolism
- Dendritic Cells/immunology
- Dendritic Cells/metabolism
- Dendritic Cells/microbiology
- Forkhead Box Protein O1/metabolism
- Humans
- Indoleamine-Pyrrole 2,3,-Dioxygenase/deficiency
- Indoleamine-Pyrrole 2,3,-Dioxygenase/genetics
- Indoleamine-Pyrrole 2,3,-Dioxygenase/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Monocytes/cytology
- Monocytes/metabolism
- Porphyromonas gingivalis/genetics
- Porphyromonas gingivalis/pathogenicity
- Proto-Oncogene Proteins c-akt/metabolism
- T-Lymphocytes, Regulatory/cytology
- T-Lymphocytes, Regulatory/immunology
- T-Lymphocytes, Regulatory/metabolism
- Th1 Cells/immunology
- Th1 Cells/metabolism
- Th17 Cells/cytology
- Th17 Cells/immunology
- Th17 Cells/metabolism
Collapse
Affiliation(s)
- Rajeev K. Tyagi
- Department of Periodontics, College of Dental Medicine, Georgia Regents University, Augusta, GA 30912, USA
- Institute of Science, Nirma University, Sarkhej-Gandhinagar Highway, Ahmedabad 382481, Gujarat, India
| | - Brodie Miles
- Division of Infectious Diseases, Anschutz Medical Campus, University of Colorado Denver, Aurora, CO 80045, USA
| | - Rajesh Parmar
- Institute of Science, Nirma University, Sarkhej-Gandhinagar Highway, Ahmedabad 382481, Gujarat, India
| | - Neeraj K. Garg
- Drug Delivery Research Group, University Institute of Pharmaceutical Sciences, UGC center of Advanced Studies, Panjab University, Chandigarh, India
| | - Sarat K. Dalai
- Institute of Science, Nirma University, Sarkhej-Gandhinagar Highway, Ahmedabad 382481, Gujarat, India
| | - Babak Baban
- Department of Oral Biology, Georgia Regents University, Augusta, GA 30912, USA
| | - Christopher W. Cutler
- Department of Periodontics, College of Dental Medicine, Georgia Regents University, Augusta, GA 30912, USA
| |
Collapse
|
30
|
El-Awady AR, Arce RM, Cutler CW. Dendritic cells: microbial clearance via autophagy and potential immunobiological consequences for periodontal disease. Periodontol 2000 2017; 69:160-80. [PMID: 26252408 PMCID: PMC4530502 DOI: 10.1111/prd.12096] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/24/2015] [Indexed: 12/15/2022]
Abstract
Dendritic cells are potent antigen‐capture and antigen‐presenting cells that play a key role in the initiation and regulation of the adaptive immune response. This process of immune homeostasis, as maintained by dendritic cells, is susceptible to dysregulation by certain pathogens during chronic infections. Such dysregulation may lead to disease perpetuation with potentially severe systemic consequences. Here we discuss in detail how intracellular pathogens exploit dendritic cells and escape degradation by altering or evading autophagy. This novel mechanism explains, in part, the chronic, persistent nature observed in several immuno‐inflammatory diseases, including periodontal disease. We also propose a hypothetical model of the plausible role of autophagy in the context of periodontal disease. Promotion of autophagy may open new therapeutic strategies in the search of a ‘cure’ for periodontal disease in humans.
Collapse
|
31
|
Goulas T, Garcia-Ferrer I, Hutcherson JA, Potempa BA, Potempa J, Scott DA, Gomis-Rüth FX. Structure of RagB, a major immunodominant outer-membrane surface receptor antigen of Porphyromonas gingivalis. Mol Oral Microbiol 2016; 31:472-485. [PMID: 26441291 PMCID: PMC4823178 DOI: 10.1111/omi.12140] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2015] [Indexed: 12/14/2022]
Abstract
Porphyromonas gingivalis is the main causative agent of periodontitis. It deregulates the inflammatory and innate host immune responses through virulence factors, which include the immunodominant outer-membrane surface receptor antigens A (PgRagA) and B (PgRagB), co-transcribed from the rag pathogenicity island. The former is predicted to be a Ton-dependent porin-type translocator but the targets of this translocation and the molecular function of PgRagB are unknown. Phenomenologically, PgRagB has been linked with epithelial cell invasion and virulence according to murine models. It also acts as a Toll-like receptor agonist and promotes multiple mediators of inflammation. Hence, PgRagB is a candidate for the development of a periodontitis vaccine, which would be facilitated by the knowledge of its atomic structure. Here, we crystallized and solved the structure of 54-kDa PgRagB, which revealed a single domain centered on a curved helical scaffold. It consists of four tetratrico peptide repeats (TPR1-4), each arranged as two helices connected by a linker, plus two extra downstream capping helices. The concave surface bears four large intertwined irregular inserts (A-D), which contribute to an overall compact moiety. Overall, PgRagB shows substantial structural similarity with Bacteroides thetaiotaomicron SusD and Tannerella forsythia NanU, which are, respectively, engaged in binding and uptake of malto-oligosaccharide/starch and sialic acid. This suggests a similar sugar-binding function for PgRagB for uptake by the cognate PgRagA translocator, and, consistently, three potential monosaccharide-binding sites were tentatively assigned on the molecular surface.
Collapse
Affiliation(s)
- T Goulas
- Proteolysis Laboratory, Department of Structural Biology ('María de Maeztu' Unit of Excellence), Molecular Biology Institute of Barcelona, CSIC, Barcelona, Spain
| | - I Garcia-Ferrer
- Proteolysis Laboratory, Department of Structural Biology ('María de Maeztu' Unit of Excellence), Molecular Biology Institute of Barcelona, CSIC, Barcelona, Spain
| | - J A Hutcherson
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry, Louisville, KY, USA
| | - B A Potempa
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry, Louisville, KY, USA
| | - J Potempa
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry, Louisville, KY, USA
- Małopolska Center of Biotechnology and Department Laboratory of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - D A Scott
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry, Louisville, KY, USA
- Department of Microbiology and Immunology, University of Louisville School of Dentistry, Louisville, KY, USA
| | - F Xavier Gomis-Rüth
- Proteolysis Laboratory, Department of Structural Biology ('María de Maeztu' Unit of Excellence), Molecular Biology Institute of Barcelona, CSIC, Barcelona, Spain.
| |
Collapse
|
32
|
Horie T, Inomata M, Into T, Hasegawa Y, Kitai N, Yoshimura F, Murakami Y. Identification of OmpA-Like Protein of Tannerella forsythia as an O-Linked Glycoprotein and Its Binding Capability to Lectins. PLoS One 2016; 11:e0163974. [PMID: 27711121 PMCID: PMC5053532 DOI: 10.1371/journal.pone.0163974] [Citation(s) in RCA: 8] [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: 06/15/2016] [Accepted: 09/16/2016] [Indexed: 11/22/2022] Open
Abstract
Bacterial glycoproteins are associated with physiological and pathogenic functions of bacteria. It remains unclear whether bacterial glycoproteins can bind to specific classes of lectins expressed on host cells. Tannerella forsythia is a gram-negative oral anaerobe that contributes to the development of periodontitis. In this study, we aimed to find lectin-binding glycoproteins in T. forsythia. We performed affinity chromatography of wheat germ agglutinin, which binds to N-acetylglucosamine (GlcNAc) and sialic acid (Sia), and identified OmpA-like protein as the glycoprotein that has the highest affinity. Mass spectrometry revealed that OmpA-like protein contains O-type N-acetylhexosamine and hexose. Fluorometry quantitatively showed that OmpA-like protein contains Sia. OmpA-like protein was found to bind to lectins including E-selectin, P-selectin, L-selectin, Siglec-5, Siglec-9, Siglec-10, and DC-SIGN. The binding of OmpA-like protein to these lectins, except for the Siglecs, depends on the presence of calcium. N-acetylneuraminic acid (NeuAc), which is the most abundant Sia, inhibited the binding of OmpA-like protein to all of these lectins, whereas GlcNAc and mannose only inhibited the binding to DC-SIGN. We further found that T. forsythia adhered to human oral epithelial cells, which express E-selectin and P-selectin, and that this adhesion was inhibited by addition of NeuAc. Moreover, adhesion of an OmpA-like protein-deficient T. forsythia strain to the cells was reduced compared to that of the wild-type strain. Our findings indicate that OmpA-like protein of T. forsythia contains O-linked sugar chains that can mediate interactions with specific lectins. This interaction is suggested to facilitate adhesion of T. forsythia to the surface of host cells.
Collapse
Affiliation(s)
- Toshi Horie
- Department of Oral Microbiology, Division of Oral Infections and Health Sciences, Asahi University School of Dentistry, Mizuho, Gifu, Japan
- Department of Orthodontics, Division of Oral Structure, Function and Development, Asahi University School of Dentistry, Mizuho, Gifu, Japan
| | - Megumi Inomata
- Department of Oral Microbiology, Division of Oral Infections and Health Sciences, Asahi University School of Dentistry, Mizuho, Gifu, Japan
- * E-mail:
| | - Takeshi Into
- Department of Oral Microbiology, Division of Oral Infections and Health Sciences, Asahi University School of Dentistry, Mizuho, Gifu, Japan
| | - Yoshiaki Hasegawa
- Department of Microbiology, School of Dentistry, Aichi Gakuin University, Nagoya, Aichi, Japan
| | - Noriyuki Kitai
- Department of Orthodontics, Division of Oral Structure, Function and Development, Asahi University School of Dentistry, Mizuho, Gifu, Japan
| | - Fuminobu Yoshimura
- Department of Microbiology, School of Dentistry, Aichi Gakuin University, Nagoya, Aichi, Japan
| | - Yukitaka Murakami
- Department of Oral Microbiology, Division of Oral Infections and Health Sciences, Asahi University School of Dentistry, Mizuho, Gifu, Japan
| |
Collapse
|
33
|
Li H, Debowski AW, Liao T, Tang H, Nilsson HO, Marshall BJ, Stubbs KA, Benghezal M. Understanding protein glycosylation pathways in bacteria. Future Microbiol 2016; 12:59-72. [PMID: 27689684 DOI: 10.2217/fmb-2016-0166] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Through advances in analytical methods to detect glycoproteins and to determine glycan structures, there have been increasing reports of protein glycosylation in bacteria. In this review, we summarize the known pathways for bacterial protein glycosylation: lipid carrier-mediated 'en bloc' glycosylation; and cytoplasmic stepwise protein glycosylation. The exploitation of bacterial protein glycosylation systems, especially the 'mix and match' of three independent but similar pathways (oligosaccharyltransferase-mediated protein glycosylation, lipopolysaccharide and peptidoglycan biosynthesis) in Gram-negative bacteria for glycoengineering recombinant glycoproteins is also discussed.
Collapse
Affiliation(s)
- Hong Li
- West China Marshall Research Centre for Infectious Diseases, Centre of Infectious Diseases, West China Hospital of Sichuan University, Chengdu 610041, China.,Helicobacter Pylori Research Laboratory, School of Pathology & Laboratory Medicine, Marshall Centre for Infectious Disease Research & Training, The University of Western Australia, M504, L Block, QEII Medical Centre, Nedlands, WA 6009, Australia
| | - Aleksandra W Debowski
- Helicobacter Pylori Research Laboratory, School of Pathology & Laboratory Medicine, Marshall Centre for Infectious Disease Research & Training, The University of Western Australia, M504, L Block, QEII Medical Centre, Nedlands, WA 6009, Australia.,School of Chemistry & Biochemistry, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Tingting Liao
- Helicobacter Pylori Research Laboratory, School of Pathology & Laboratory Medicine, Marshall Centre for Infectious Disease Research & Training, The University of Western Australia, M504, L Block, QEII Medical Centre, Nedlands, WA 6009, Australia
| | - Hong Tang
- West China Marshall Research Centre for Infectious Diseases, Centre of Infectious Diseases, West China Hospital of Sichuan University, Chengdu 610041, China
| | - Hans-Olof Nilsson
- Ondek Pty Ltd, School of Pathology & Laboratory Medicine, Marshall Centre for Infectious Disease Research & Training, The University of Western Australia, M504, L Block, QEII Medical Centre, Nedlands, WA 6009, Australia
| | - Barry J Marshall
- Helicobacter Pylori Research Laboratory, School of Pathology & Laboratory Medicine, Marshall Centre for Infectious Disease Research & Training, The University of Western Australia, M504, L Block, QEII Medical Centre, Nedlands, WA 6009, Australia
| | - Keith A Stubbs
- School of Chemistry & Biochemistry, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Mohammed Benghezal
- Helicobacter Pylori Research Laboratory, School of Pathology & Laboratory Medicine, Marshall Centre for Infectious Disease Research & Training, The University of Western Australia, M504, L Block, QEII Medical Centre, Nedlands, WA 6009, Australia.,Swiss Vitamin Institute, Route de la Corniche 1, CH-1066 Epalinges, Switzerland
| |
Collapse
|
34
|
Schäffer C, Messner P. Emerging facets of prokaryotic glycosylation. FEMS Microbiol Rev 2016; 41:49-91. [PMID: 27566466 DOI: 10.1093/femsre/fuw036] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 02/17/2016] [Accepted: 08/01/2016] [Indexed: 12/16/2022] Open
Abstract
Glycosylation of proteins is one of the most prevalent post-translational modifications occurring in nature, with a wide repertoire of biological implications. Pathways for the main types of this modification, the N- and O-glycosylation, can be found in all three domains of life-the Eukarya, Bacteria and Archaea-thereby following common principles, which are valid also for lipopolysaccharides, lipooligosaccharides and glycopolymers. Thus, studies on any glycoconjugate can unravel novel facets of the still incompletely understood fundamentals of protein N- and O-glycosylation. While it is estimated that more than two-thirds of all eukaryotic proteins would be glycosylated, no such estimate is available for prokaryotic glycoproteins, whose understanding is lagging behind, mainly due to the enormous variability of their glycan structures and variations in the underlying glycosylation processes. Combining glycan structural information with bioinformatic, genetic, biochemical and enzymatic data has opened up an avenue for in-depth analyses of glycosylation processes as a basis for glycoengineering endeavours. Here, the common themes of glycosylation are conceptualised for the major classes of prokaryotic (i.e. bacterial and archaeal) glycoconjugates, with a special focus on glycosylated cell-surface proteins. We describe the current knowledge of biosynthesis and importance of these glycoconjugates in selected pathogenic and beneficial microbes.
Collapse
Affiliation(s)
- Christina Schäffer
- Department of NanoBiotechnology, Institute of Biologically Inspired Materials, NanoGlycobiology unit, Universität für Bodenkultur Wien, A-1180 Vienna, Austria
| | - Paul Messner
- Department of NanoBiotechnology, Institute of Biologically Inspired Materials, NanoGlycobiology unit, Universität für Bodenkultur Wien, A-1180 Vienna, Austria
| |
Collapse
|
35
|
Reyes L, Herrera D, Kozarov E, Roldán S, Progulske-Fox A. Periodontal bacterial invasion and infection: contribution to atherosclerotic pathology. J Clin Periodontol 2016; 40 Suppl 14:S30-50. [PMID: 23627333 DOI: 10.1111/jcpe.12079] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/14/2012] [Indexed: 12/16/2022]
Abstract
OBJECTIVE The objective of this review was to perform a systematic evaluation of the literature reporting current scientific evidence for periodontal bacteria as contributors to atherosclerosis. METHODS Literature from epidemiological, clinical and experimental studies concerning periodontal bacteria and atherosclerosis were reviewed. Gathered data were categorized into seven "proofs" of evidence that periodontal bacteria: 1) disseminate from the oral cavity and reach systemic vascular tissues; 2) can be found in the affected tissues; 3) live within the affected site; 4) invade affected cell types in vitro; 5) induce atherosclerosis in animal models of disease; 6) non-invasive mutants of periodontal bacteria cause significantly reduced pathology in vitro and in vivo; and 7) periodontal isolates from human atheromas can cause disease in animal models of infection. RESULTS Substantial evidence for proofs 1 to 6 was found. However, proof 7 has not yet been fulfilled. CONCLUSIONS Despite the lack of evidence that periodontal bacteria obtained from human atheromas can cause atherosclerosis in animal models of infection, attainment of proofs 1 to 6 provides support that periodontal pathogens can contribute to atherosclerosis.
Collapse
Affiliation(s)
- Leticia Reyes
- Department of Oral Biology, College of Dentistry and Center for Molecular Microbiology, University of Florida, Gainesville, FL 32610-0424, USA
| | | | | | | | | |
Collapse
|
36
|
Zenobia C, Hajishengallis G. Porphyromonas gingivalis virulence factors involved in subversion of leukocytes and microbial dysbiosis. Virulence 2016; 6:236-43. [PMID: 25654623 PMCID: PMC4601496 DOI: 10.1080/21505594.2014.999567] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The oral bacterium Porphyromonas gingivalis has special nutrient requirements due to its asaccharolytic nature subsisting on small peptides cleaved from host proteins. Using proteases and other virulence factors, P. gingivalis thrives as a component of a polymicrobial community in nutritionally favorable inflammatory environments. In this regard, P. gingivalis has a number of strategies that subvert the host immune response in ways that promote its colonization and facilitate the outgrowth of the surrounding microbial community. The focus of this review is to discuss at the molecular level how P. gingivalis subverts leukocytes to create a favorable environment for a select community of bacteria that, in turn, adversely affects the periodontal tissues.
Collapse
Affiliation(s)
- Camille Zenobia
- a Department of Microbiology; University of Pennsylvania School of Dental Medicine ; Philadelphia , PA , USA
| | | |
Collapse
|
37
|
Zhu F, Wu H. Insights into bacterial protein glycosylation in human microbiota. SCIENCE CHINA. LIFE SCIENCES 2016; 59:11-8. [PMID: 26712033 PMCID: PMC5298937 DOI: 10.1007/s11427-015-4980-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Accepted: 11/05/2015] [Indexed: 01/14/2023]
Abstract
The study of human microbiota is an emerging research topic. The past efforts have mainly centered on studying the composition and genomic landscape of bacterial species within the targeted communities. The interaction between bacteria and hosts is the pivotal event in the initiation and progression of infectious diseases. There is a great need to identify and characterize the molecules that mediate the bacteria-host interaction. Bacterial surface exposed proteins play an important role in the bacteria- host interaction. Numerous surface proteins are glycosylated, and the glycosylation is crucial for their function in mediating the bacterial interaction with hosts. Here we present an overview of surface glycoproteins from bacteria that inhabit three major mucosal environments across human body: oral, gut and skin. We describe the important enzymes involved in the process of protein glycosylation, and discuss how the process impacts the bacteria-host interaction. Emerging molecular details underlying glycosylation of bacterial surface proteins may lead to new opportunities for designing anti-infective small molecules, and developing novel vaccines in order to treat or prevent bacterial infection.
Collapse
Affiliation(s)
- Fan Zhu
- Departments of Microbiology and Pediatric Dentistry, Schools of Dentistry and Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Hui Wu
- Departments of Microbiology and Pediatric Dentistry, Schools of Dentistry and Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
| |
Collapse
|
38
|
Arjunan P, El-Awady A, Dannebaum RO, Kunde-Ramamoorthy G, Cutler CW. High-throughput sequencing reveals key genes and immune homeostatic pathways activated in myeloid dendritic cells by Porphyromonas gingivalis 381 and its fimbrial mutants. Mol Oral Microbiol 2015; 31:78-93. [PMID: 26466817 DOI: 10.1111/omi.12131] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2015] [Indexed: 12/14/2022]
Abstract
The human microbiome consists of highly diverse microbial communities that colonize our skin and mucosal surfaces, aiding in maintenance of immune homeostasis. The keystone pathogen Porphyromonas gingivalis induces a dysbiosis and disrupts immune homeostasis through as yet unclear mechanisms. The fimbrial adhesins of P. gingivalis facilitate biofilm formation, invasion of and dissemination by blood dendritic cells; hence, fimbriae may be key factors in disruption of immune homeostasis. In this study we employed RNA-sequencing transcriptome profiling to identify differentially expressed genes (DEGs) in human monocyte-derived dendritic cells (MoDCs) in response to in vitro infection/exposure by Pg381 or its isogenic mutant strains that solely express minor-Mfa1 fimbriae (DPG3), major-FimA fimbriae (MFI) or are deficient in both fimbriae (MFB) relative to uninfected control. Our results yielded a total of 479 DEGs that were at least two-fold upregulated and downregulated in MoDCs significantly (P ≤ 0.05) by all four strains and certain DEGs that were strain-specific. Interestingly, the gene ontology biological and functional analysis shows that the upregulated genes in DPG3-induced MoDCs were more significant than other strains and associated with inflammation, immune response, anti-apoptosis, cell proliferation, and other homeostatic functions. Both transcriptome and quantitative polymerase chain reaction results show that DPG3, which solely expresses Mfa1, increased ZNF366, CD209, LOX1, IDO1, IL-10, CCL2, SOCS3, STAT3 and FOXO1 gene expression. In conclusion, we have identified key DC-mediated immune homeostatic pathways that could contribute to dysbiosis in periodontal infection with P. gingivalis.
Collapse
Affiliation(s)
- P Arjunan
- Department of Periodontics, Georgia Regents University, Augusta, GA, USA
| | - A El-Awady
- Department of Periodontics, Georgia Regents University, Augusta, GA, USA
| | - R O Dannebaum
- Department of Energy, Joint Genome Institute, Walnut Creek, CA, USA
| | - G Kunde-Ramamoorthy
- Department of Energy, Joint Genome Institute, Walnut Creek, CA, USA.,Department of Biochemistry, National University of Singapore, Singapore
| | - C W Cutler
- Department of Periodontics, Georgia Regents University, Augusta, GA, USA
| |
Collapse
|
39
|
Shoji M, Nakayama K. Glycobiology of the oral pathogen Porphyromonas gingivalis and related species. Microb Pathog 2015; 94:35-41. [PMID: 26456570 DOI: 10.1016/j.micpath.2015.09.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 09/29/2015] [Accepted: 09/30/2015] [Indexed: 10/22/2022]
Abstract
Until recently, glycoproteins had only been described in eukaryotes. However, advances in detection methods and genome analyses have allowed the discovery of N-linked or O-linked glycoproteins, similar to those found in eukaryotes, in some bacterial species. These prokaryotic glycoproteins play roles in adhesion, solubility, formation of protein complexes, protection from protein degradation, and changes in antigenicity. Periodontal pathogen Porphyromonas gingivalis secretes virulence proteins via the type IX secretion system, some of which localize on the cell surface by binding to lipopolysaccharide (LPS). These virulence proteins have a conserved C-terminal domain (CTD) region, which is used as a secretion signal. However, it is still uncertain how the secreted proteins on the cell surface bind to LPS. In this review, we discuss the synthesis of P. gingivalis O polysaccharide, which plays a role in anchoring the CTD protein on the cell surface, and recent discoveries of glycoproteins in P. gingivalis as well as other species in the phylum Bacteroidetes.
Collapse
Affiliation(s)
- Mikio Shoji
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, 852-8588, Japan
| | - Koji Nakayama
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, 852-8588, Japan.
| |
Collapse
|
40
|
The sweet tooth of bacteria: common themes in bacterial glycoconjugates. Microbiol Mol Biol Rev 2015; 78:372-417. [PMID: 25184559 DOI: 10.1128/mmbr.00007-14] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Humans have been increasingly recognized as being superorganisms, living in close contact with a microbiota on all their mucosal surfaces. However, most studies on the human microbiota have focused on gaining comprehensive insights into the composition of the microbiota under different health conditions (e.g., enterotypes), while there is also a need for detailed knowledge of the different molecules that mediate interactions with the host. Glycoconjugates are an interesting class of molecules for detailed studies, as they form a strain-specific barcode on the surface of bacteria, mediating specific interactions with the host. Strikingly, most glycoconjugates are synthesized by similar biosynthesis mechanisms. Bacteria can produce their major glycoconjugates by using a sequential or an en bloc mechanism, with both mechanistic options coexisting in many species for different macromolecules. In this review, these common themes are conceptualized and illustrated for all major classes of known bacterial glycoconjugates, with a special focus on the rather recently emergent field of glycosylated proteins. We describe the biosynthesis and importance of glycoconjugates in both pathogenic and beneficial bacteria and in both Gram-positive and -negative organisms. The focus lies on microorganisms important for human physiology. In addition, the potential for a better knowledge of bacterial glycoconjugates in the emerging field of glycoengineering and other perspectives is discussed.
Collapse
|
41
|
Abstract
Periodontitis is a dysbiotic inflammatory disease with an adverse impact on systemic health. Recent studies have provided insights into the emergence and persistence of dysbiotic oral microbial communities that can mediate inflammatory pathology at local as well as distant sites. This Review discusses the mechanisms of microbial immune subversion that tip the balance from homeostasis to disease in oral or extra-oral sites.
Collapse
|
42
|
Abstract
Oral colonising bacteria are highly adapted to the various environmental niches harboured within the mouth, whether that means while contributing to one of the major oral diseases of caries, pulp infections, or gingival/periodontal disease or as part of a commensal lifestyle. Key to these infections is the ability to adhere to surfaces via a range of specialised adhesins targeted at both salivary and epithelial proteins, their glycans and to form biofilm. They must also resist the various physical stressors they are subjected to, including pH and oxidative stress. Possibly most strikingly, they have developed the ability to harvest both nutrient sources provided by the diet and those derived from the host, such as protein and surface glycans. We have attempted to review recent developments that have revealed much about the molecular mechanisms at work in shaping the physiology of oral bacteria and how we might use this information to design and implement new treatment strategies.
Collapse
|
43
|
Characterization of wheat germ agglutinin lectin-reactive glycosylated OmpA-like proteins derived from Porphyromonas gingivalis. Infect Immun 2014; 82:4563-71. [PMID: 25135681 DOI: 10.1128/iai.02069-14] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Glycosylation is one of the common posttranslational modifications in eukaryotes. Recently, glycosylated proteins have also been identified in prokaryotes. A few glycosylated proteins, including gingipains, have been identified in Porphyromonas gingivalis, a major pathogen associated with chronic periodontitis. However, no other glycosylated proteins have been found. The present study identified glycoproteins in P. gingivalis cell lysates by lectin blotting. Whole-cell lysates reacted with concanavalin A (ConA), Lens culinaris agglutinin (LCA), Phaseolus vulgaris erythroagglutinin (PHA-E4), and wheat germ agglutinin (WGA), suggesting the presence of mannose-, N-acetylgalactosamine-, or N-acetylglucosamine (GlcNAc)-modified proteins. Next, glycoproteins were isolated by ConA-, LCA-, PHA-E4-, or WGA-conjugated lectin affinity chromatography although specific proteins were enriched only by the WGA column. Mass spectrometry analysis showed that an OmpA-like, heterotrimeric complex formed by Pgm6 and Pgm7 (Pgm6/7) was the major glycoprotein isolated from P. gingivalis. Deglycosylation experiments and Western blotting with a specific antibody indicated that Pgm6/7 was modified with O-GlcNAc. When whole-cell lysates from P. gingivalis mutant strains with deletions of Pgm6 and Pgm7 were applied to a WGA column, homotrimeric Pgm7, but not Pgm6, was isolated. Heterotrimeric Pgm6/7 had the strongest affinity for fibronectin of all the extracellular proteins tested, whereas homotrimeric Pgm7 showed reduced binding activity. These findings suggest that the heterotrimeric structure is important for the biological activity of glycosylated WGA-binding OmpA-like proteins in P. gingivalis.
Collapse
|
44
|
Shoji M, Sato K, Yukitake H, Naito M, Nakayama K. Involvement of the Wbp pathway in the biosynthesis of Porphyromonas gingivalis lipopolysaccharide with anionic polysaccharide. Sci Rep 2014; 4:5056. [PMID: 24852504 PMCID: PMC4031482 DOI: 10.1038/srep05056] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 05/06/2014] [Indexed: 11/15/2022] Open
Abstract
The periodontal pathogen Porphyromonas gingivalis has two different lipopolysaccharide (LPS) molecules, O-LPS and A-LPS. We have recently shown that P. gingivalis strain HG66 lacks A-LPS. Here, we found that introduction of a wild-type wbpB gene into strain HG66 restored formation of A-LPS. Sequencing of the wbpB gene from strain HG66 revealed the presence of a nonsense mutation in the gene. The wbpB gene product is a member of the Wbp pathway, which plays a role in the synthesis of UDP-ManNAc(3NAc)A in Pseudomonas aeruginosa; UDP-ManNAc(3NAc)A is sequentially synthesized by the WbpA, WbpB, WbpE, WbpD and WbpI proteins. We then determined the effect of the PGN_0002 gene, a wbpD homolog, on the biosynthesis of A-LPS. A PGN_0002-deficient mutant demonstrated an A-LPS biosynthesis deficiency. Taken together with previous studies, the present results suggest that the final product synthesized by the Wbp pathway is one of the sugar substrates necessary for the biosynthesis of A-LPS.
Collapse
Affiliation(s)
- Mikio Shoji
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, 852-8588, Japan
| | - Keiko Sato
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, 852-8588, Japan
| | - Hideharu Yukitake
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, 852-8588, Japan
| | - Mariko Naito
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, 852-8588, Japan
| | - Koji Nakayama
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, 852-8588, Japan
| |
Collapse
|
45
|
Miles B, Abdel-Ghaffar KA, Gamal AY, Baban B, Cutler CW. Blood dendritic cells: "canary in the coal mine" to predict chronic inflammatory disease? Front Microbiol 2014; 5:6. [PMID: 24478766 PMCID: PMC3902297 DOI: 10.3389/fmicb.2014.00006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 01/07/2014] [Indexed: 12/19/2022] Open
Abstract
The majority of risk factors for chronic inflammatory diseases are unknown. This makes personalized medicine for assessment, prognosis, and choice of therapy very difficult. It is becoming increasingly clear, however, that low-grade subclinical infections may be an underlying cause of many chronic inflammatory diseases and thus may contribute to secondary outcomes (e.g., cancer). Many diseases are now categorized as inflammatory-mediated diseases that stem from a dysregulation in host immunity. There is a growing need to study the links between low-grade infections, the immune responses they elicit, and how this impacts overall health. One such link explored in detail here is the extreme sensitivity of myeloid dendritic cells (mDCs) in peripheral blood to chronic low-grade infections and the role that these mDCs play in arbitrating the resulting immune responses. We find that emerging evidence supports a role for pathogen-induced mDCs in chronic inflammation leading to increased risk of secondary clinical disease. The mDCs that are elevated in the blood as a result of low-grade bacteremia often do not trigger a productive immune response, but can disseminate the pathogen throughout the host. This aberrant trafficking of mDCs can accelerate systemic inflammatory disease progression. Conversely, restoration of dendritic cell homeostasis may aid in pathogen elimination and minimize dissemination. Thus it would seem prudent when assessing chronic inflammatory disease risk to consider blood mDC numbers, and the microbial content (microbiome) and activation state of these mDCs. These may provide important clues (“the canary in the coal mine”) of high inflammatory disease risk. This will facilitate development of novel immunotherapies to eliminate such smoldering infections in atherosclerosis, cancer, rheumatoid arthritis, and pre-eclampsia.
Collapse
Affiliation(s)
- Brodie Miles
- Department of Periodontics, College of Dental Medicine, Georgia Regents University Augusta, GA, USA
| | | | | | - Babak Baban
- Department of Oral Biology, Georgia Regents University Augusta, GA, USA
| | - Christopher W Cutler
- Department of Periodontics, College of Dental Medicine, Georgia Regents University Augusta, GA, USA
| |
Collapse
|
46
|
Settem RP, Honma K, Stafford GP, Sharma A. Protein-linked glycans in periodontal bacteria: prevalence and role at the immune interface. Front Microbiol 2013; 4:310. [PMID: 24146665 PMCID: PMC3797959 DOI: 10.3389/fmicb.2013.00310] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 09/27/2013] [Indexed: 12/20/2022] Open
Abstract
Protein modification with complex glycans is increasingly being recognized in many pathogenic and non-pathogenic bacteria, and is now thought to be central to the successful life-style of those species in their respective hosts. This review aims to convey current knowledge on the extent of protein glycosylation in periodontal pathogenic bacteria and its role in the modulation of the host immune responses. The available data show that surface glycans of periodontal bacteria orchestrate dendritic cell cytokine responses to drive T cell immunity in ways that facilitate bacterial persistence in the host and induce periodontal inflammation. In addition, surface glycans may help certain periodontal bacteria protect against serum complement attack or help them escape immune detection through glycomimicry. In this review we will focus mainly on the generalized surface-layer protein glycosylation system of the periodontal pathogen Tannerella forsythia in shaping innate and adaptive host immunity in the context of periodontal disease. In addition, we will also review the current state of knowledge of surface protein glycosylation and its potential for immune modulation in other periodontal pathogens.
Collapse
Affiliation(s)
- Rajendra P Settem
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, State University of New York Buffalo, NY, USA
| | | | | | | |
Collapse
|
47
|
Secondary lymphoid organ homing phenotype of human myeloid dendritic cells disrupted by an intracellular oral pathogen. Infect Immun 2013; 82:101-11. [PMID: 24126519 DOI: 10.1128/iai.01157-13] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Several intracellular pathogens, including a key etiological agent of chronic periodontitis, Porphyromonas gingivalis, infect blood myeloid dendritic cells (mDCs). This infection results in pathogen dissemination to distant inflammatory sites (i.e., pathogen trafficking). The alteration in chemokine-chemokine receptor expression that contributes to this pathogen trafficking function, particularly toward sites of neovascularization in humans, is unclear. To investigate this, we utilized human monocyte-derived DCs (MoDCs) and primary endothelial cells in vitro, combined with ex vivo-isolated blood mDCs and serum from chronic periodontitis subjects and healthy controls. Our results, using conditional fimbria mutants of P. gingivalis, show that P. gingivalis infection of MoDCs induces an angiogenic migratory profile. This profile is enhanced by expression of DC-SIGN on MoDCs and minor mfa-1 fimbriae on P. gingivalis and is evidenced by robust upregulation of CXCR4, but not secondary lymphoid organ (SLO)-homing CCR7. This disruption of SLO-homing capacity in response to respective chemokines closely matches surface expression of CXCR4 and CCR7 and is consistent with directed MoDC migration through an endothelial monolayer. Ex vivo-isolated mDCs from the blood of chronic periodontitis subjects, but not healthy controls, expressed a similar migratory profile; moreover, sera from chronic periodontitis subjects expressed elevated levels of CXCL12. Overall, we conclude that P. gingivalis actively "commandeers" DCs by reprogramming the chemokine receptor profile, thus disrupting SLO homing, while driving migration toward inflammatory vascular sites.
Collapse
|
48
|
Wang Q, Wright CJ, Dingming H, Uriarte SM, Lamont RJ. Oral community interactions of Filifactor alocis in vitro. PLoS One 2013; 8:e76271. [PMID: 24098460 PMCID: PMC3789735 DOI: 10.1371/journal.pone.0076271] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 08/23/2013] [Indexed: 11/18/2022] Open
Abstract
Filifactor alocis is a gram positive anaerobe that is emerging as an important periodontal pathogen. In the oral cavity F. alocis colonizes polymicrobial biofilm communities; however, little is known regarding the nature of the interactions between F. alocis and other oral biofilm bacteria. Here we investigate the community interactions of two strains of F. alocis with Streptococcus gordonii, Fusobacterium nucleatum, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, organisms with differing pathogenic potential in the oral cavity. In an in vitro community development model, S. gordonii was antagonistic to the accumulation of F. alocis into a dual species community. In contrast, F. nucleatum and the type strain of F. alocis formed a synergistic partnership. Accumulation of a low passage isolate of F. alocis was also enhanced by F. nucleatum. In three species communities of S. gordonii, F. nucleatum and F. alocis, the antagonistic effects of S. gordonii superseded the synergistic effects of F. nucleatum toward F. alocis. The interaction between A. actinomycetemcomitans and F. alocis was strain specific and A. actinomycetemcomitans could either stimulate F. alocis accumulation or have no effect depending on the strain. P. gingivalis and F. alocis formed heterotypic communities with the amount of P. gingivalis greater than in the absence of F. alocis. However, while P. gingivalis benefited from the relationship, levels of F. alocis in the dual species community were lower compared to F. alocis alone. The inhibitory effect of P. gingivalis toward F. alocis was dependent, at least partially, on the presence of the Mfa1 fimbrial subunit. In addition, AI-2 production by P. gingivalis helped maintain levels of F. alocis. Collectively, these results show that the pattern of F. alocis colonization will be dictated by the spatial composition of microbial microenvironments, and that the organism may preferentially accumulate at sites rich in F. nucleatum.
Collapse
Affiliation(s)
- Qian Wang
- Center for Oral Health and Systemic Disease, School of Dentistry, University of Louisville, Louisville, Kentucky, United States of America
- State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, China
| | - Christopher J. Wright
- Center for Oral Health and Systemic Disease, School of Dentistry, University of Louisville, Louisville, Kentucky, United States of America
| | - Huang Dingming
- State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, China
| | - Silvia M. Uriarte
- Department of Medicine, University of Louisville, Louisville, Kentucky, United States of America
| | - Richard J. Lamont
- Center for Oral Health and Systemic Disease, School of Dentistry, University of Louisville, Louisville, Kentucky, United States of America
- * E-mail:
| |
Collapse
|
49
|
Miles B, Scisci E, Carrion J, Sabino GJ, Genco CA, Cutler CW. Noncanonical dendritic cell differentiation and survival driven by a bacteremic pathogen. J Leukoc Biol 2013; 94:281-9. [PMID: 23729500 DOI: 10.1189/jlb.0213108] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Maintenance of blood DC homeostasis is essential to preventing autoimmunity while controlling chronic infection. However, the ability of bacteremic pathogens to directly regulate blood DC homeostasis has not been defined. One such bacteremic pathogen, Porphyromonas gingivalis, is shown by our group to survive within mDCs under aerobic conditions and therein, metastasize from its oral mucosal niche. This is accompanied by expansion of the blood mDC pool in vivo, independently of canonical DC poietins. We presently know little of how this bacteremic pathogen causes blood DC expansion and the pathophysiological significance. This work shows that optimum differentiation of MoDCs from primary human monocytes, with or without GM-CSF/IL-4, is dependent on infection with P. gingivalis strains expressing the DC-SIGN ligand mfa-1. DC differentiation is lost when DC-SIGN is blocked with its ligand HIV gp120 or knocked out by siRNA gene silencing. Thus, we have identified a novel, noncanonical pathway of DC differentiation. We term these PDDCs and show that PDDCs are bona fide DCs, based on phenotype and phagocytic activity when immature and the ability to up-regulate accessory molecules and stimulate allo-CD4(+) T cell proliferation when matured. The latter is dependent on the P. gingivalis strain used to initially "educate" PDDCs. Moreover, we show that P. gingivalis-infected, conventional MoDCs become resistant to apoptosis and inflammatory pyroptosis, as determined by levels of Annexin V and caspase-8, -3/7, and -1. Taken together, we provide new insights into how a relatively asymptomatic bacteremia may influence immune homeostasis and promote chronic inflammation.
Collapse
Affiliation(s)
- Brodie Miles
- 1.Georgia Regent University Augusta, 1120 15th St., GC-1335, Augusta, GA 30912, USA.
| | | | | | | | | | | |
Collapse
|
50
|
Shoji M, Yukitake H, Sato K, Shibata Y, Naito M, Aduse-Opoku J, Abiko Y, Curtis MA, Nakayama K. Identification of an O-antigen chain length regulator, WzzP, in Porphyromonas gingivalis. Microbiologyopen 2013; 2:383-401. [PMID: 23509024 PMCID: PMC3684754 DOI: 10.1002/mbo3.84] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 02/11/2013] [Accepted: 02/19/2013] [Indexed: 01/22/2023] Open
Abstract
The periodontal pathogen Porphyromonas gingivalis has two different lipopolysaccharides (LPSs) designated O-LPS and A-LPS, which are a conventional O-antigen polysaccharide and an anionic polysaccharide that are both linked to lipid A-cores, respectively. However, the precise mechanisms of LPS biosynthesis remain to be determined. In this study, we isolated a pigment-less mutant by transposon mutagenesis and identified that the transposon was inserted into the coding sequence PGN_2005, which encodes a hypothetical protein of P. gingivalis ATCC 33277. We found that (i) LPSs purified from the PGN_2005 mutant were shorter than those of the wild type; (ii) the PGN_2005 protein was located in the inner membrane fraction; and (iii) the PGN_2005 gene conferred Wzz activity upon an Escherichia coli wzz mutant. These results indicate that the PGN_2005 protein, which was designated WzzP, is a functional homolog of the Wzz protein in P. gingivalis. Comparison of amino acid sequences among WzzP and conventional Wzz proteins indicated that WzzP had an additional fragment at the C-terminal region. In addition, we determined that the PGN_1896 and PGN_1233 proteins and the PGN_1033 protein appear to be WbaP homolog proteins and a Wzx homolog protein involved in LPS biosynthesis, respectively.
Collapse
Affiliation(s)
- Mikio Shoji
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, 852-8588, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|