Treponema denticola-Induced RASA4 Upregulation Mediates Cytoskeletal Dysfunction and MMP-2 Activity in Periodontal Fibroblasts

The periodontal complex consists of the periodontal ligament (PDL), alveolar bone, and cementum, which work together to turn mechanical load into biological responses that are responsible for maintaining a homeostatic environment. However oral microbes, under conditions of dysbiosis, may challenge the actin dynamic properties of the PDL in the context of periodontal disease. To study this process, we examined host-microbial interactions in the context of the periodontium via molecular and functional cell assays and showed that human PDL cell interactions with Treponema denticola induce actin depolymerization through a novel actin reorganization signaling mechanism. This actin reorganization mechanism and loss of cell adhesion is a pathological response characterized by an initial upregulation of RASA4 mRNA expression resulting in an increase in matrix metalloproteinase-2 activity. This mechanism is specific to the T. denticola effector protein, dentilisin, thereby uncovering a novel effect for Treponema denticola-mediated RASA4 transcriptional activation and actin depolymerization in primary human PDL cells.

Download Full-text

TheTreponema denticolaChymotrypsin-Like Protease Dentilisin Induces Matrix Metalloproteinase-2-Dependent Fibronectin Fragmentation in Periodontal Ligament Cells

Infection and Immunity ◽

10.1128/iai.01001-10 ◽

2010 ◽

Vol 79 (2) ◽

pp. 806-811 ◽

Cited By ~ 14

Author(s):

Di Miao ◽

J. Christopher Fenno ◽

John C. Timm ◽

Nam Eok Joo ◽

Yvonne L. Kapila

Keyword(s):

Periodontal Disease ◽

Periodontal Ligament ◽

Alveolar Bone ◽

Inflammatory Responses ◽

Tissue Homeostasis ◽

Matrix Metalloproteinase 2 ◽

Periodontal Ligament Cells ◽

Treponema Denticola ◽

Periodontal Pathogens ◽

Culture Supernatants

ABSTRACTPeriodontal disease is a bacterially mediated chronic inflammatory disease that results in destruction of the periodontal ligament (PDL) and alveolar bone that surround and support the dentition. While their precise roles are not well understood, periodontal pathogens, includingTreponema denticola, are believed to initiate the destructive inflammatory responses and dysregulation of tissue homeostasis that characterize the disease. These responses are believed to result from both proinflammatory effects of acylated bacterial membrane components (lipopolysaccharides and lipoproteins) and degradative effects of secreted bacterial proteases. Host-derived matrix metalloproteinases (MMPs) are key enzymes both in tissue homeostasis and tissue destruction. MMP expression is modulated in part by specific proteolytic fragments of fibronectin (FN), which are associated with periodontal disease. FN is a predominant extracellular matrix component in the periodontium. We examined the ability ofTreponema denticolaand its acylated outer membrane PrtP protease complex to induce both activation of MMP-2 and generation of FN fragments in human PDL cell culture supernatants.T. denticolaparent and isogenic mutant strains, as well as MMP-2 small interfering RNA and specific inhibitors of MMP-2 and PrtP activity, were used to examine protein expression, gelatinolytic activity, and FN fragmentation in culture supernatants.T. denticolaand its purified protease induced both MMP-2 activation and FN fragmentation. Here, we demonstrate that PrtP proteolytic activity induces the activation of MMP-2 and that active MMP-2 is required for FN fragmentation. These results suggest a specific mechanism by which theT. denticolaprotease may disrupt homeostatic processes required for the maintenance of periodontal health.

Download Full-text

Second messenger Ap4A polymerizes target protein HINT1 to transduce signals in FcεRI-activated mast cells

Nature Communications ◽

10.1038/s41467-019-12710-8 ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 1

Author(s):

Jing Yu ◽

Zaizhou Liu ◽

Yuanyuan Liang ◽

Feng Luo ◽

Jie Zhang ◽

...

Keyword(s):

Mast Cells ◽

Transcriptional Activation ◽

Second Messenger ◽

Signaling Mechanism ◽

Cellular Processes ◽

Negative Stain ◽

Competitive Mechanism ◽

Rat Basophilic Leukemia Cells ◽

Negative Stain Electron Microscopy ◽

Basophilic Leukemia

Abstract Signal transduction systems enable organisms to monitor their external environments and accordingly adjust the cellular processes. In mast cells, the second messenger Ap4A binds to the histidine triad nucleotide-binding protein 1 (HINT1), disrupts its interaction with the microphthalmia-associated transcription factor (MITF), and eventually activates the transcription of genes downstream of MITF in response to immunostimulation. How the HINT1 protein recognizes and is regulated by Ap4A remain unclear. Here, using eight crystal structures, biochemical experiments, negative stain electron microscopy, and cellular experiments, we report that Ap4A specifically polymerizes HINT1 in solution and in activated rat basophilic leukemia cells. The polymerization interface overlaps with the area on HINT1 for MITF interaction, suggesting a possible competitive mechanism to release MITF for transcriptional activation. The mechanism depends precisely on the length of the phosphodiester linkage of Ap4A. These results highlight a direct polymerization signaling mechanism by the second messenger.

Download Full-text

Invasion of Oral and Aortic Tissues by Oral Spirochete Treponema denticola in ApoE−/−Mice Causally Links Periodontal Disease and Atherosclerosis

Infection and Immunity ◽

10.1128/iai.01511-14 ◽

2014 ◽

Vol 82 (5) ◽

pp. 1959-1967 ◽

Cited By ~ 32

Author(s):

Sasanka S. Chukkapalli ◽

Mercedes F. Rivera ◽

Irina M. Velsko ◽

Ju-Youn Lee ◽

Hao Chen ◽

...

Keyword(s):

Periodontal Disease ◽

Alveolar Bone ◽

Tissue Growth ◽

Aortic Tissue ◽

Treponema Denticola ◽

Rapid Progression ◽

Causative Role ◽

Igg Antibody ◽

Content Type ◽

Periodontal Infection

ABSTRACTTreponema denticolais a predominantly subgingival oral spirochete closely associated with periodontal disease and has been detected in atherosclerosis. This study was designed to evaluate causative links between periodontal disease induced by chronic oralT. denticolainfection and atherosclerosis in hyperlipidemic ApoE−/−mice. ApoE−/−mice (n= 24) were orally infected withT. denticolaATCC 35404 and were euthanized after 12 and 24 weeks.T. denticolagenomic DNA was detected in oral plaque samples, indicating colonization of the oral cavity. Infection elicited significantly (P= 0.0172) higher IgG antibody levels and enhanced intrabony defects than sham infection.T. denticola-infected mice had higher levels of horizontal alveolar bone resorption than sham-infected mice and an associated significant increase in aortic plaque area (P≤ 0.05). Increased atherosclerotic plaque correlated with reduced serum nitric oxide (NO) levels and increased serum-oxidized low-density lipoprotein (LDL) levels compared to those of sham-infected mice.T. denticolainfection altered the expression of genes known to be involved in atherosclerotic development, including the leukocyte/endothelial cell adhesion gene (Thbs4), the connective tissue growth factor gene (Ctgf), and the selectin-E gene (Sele). Fluorescentin situhybridization (FISH) revealedT. denticolaclusters in both gingival and aortic tissue of infected mice. This is the first study examining the potential causative role of chronicT. denticolaperiodontal infection and vascular atherosclerosisin vivoin hyperlipidemic ApoE−/−mice.T. denticolais closely associated with periodontal disease and the rapid progression of atheroma in ApoE−/−mice. These studies confirm a causal link for active oralT. denticolainfection with both atheroma and periodontal disease.

Download Full-text

Induction of De Novo Subcortical Actin Filament Assembly by Treponema denticola Major Outer Sheath Protein

Infection and Immunity ◽

10.1128/iai.72.6.3650-3654.2004 ◽

2004 ◽

Vol 72 (6) ◽

pp. 3650-3654 ◽

Cited By ~ 20

Author(s):

Mohsen Amin ◽

Andy C. S. Ho ◽

Jenny Y. Lin ◽

Andre Paes Batista da Silva ◽

Michael Glogauer ◽

...

Keyword(s):

Actin Filament ◽

De Novo ◽

Cell Types ◽

Treponema Denticola ◽

Actin Reorganization ◽

Filament Assembly ◽

Outer Sheath

ABSTRACT Treponema denticola and its major outer sheath protein (Msp) induce actin reorganization in fibroblasts. We adapted a barbed-end labeling/imaging assay to monitor Msp-induced subcortical actin filament assembly in neutrophils and fibroblasts. Msp, at an actin-reorganizing concentration, inhibited migration of these dissimilar cell types, whose cytoskeletal functions in locomotion and phagocytosis are crucial for immunity and healing of peripheral infections.

Download Full-text

Trypsin Mediates Growth Phase-Dependent Transcriptional Regulation of Genes Involved in Biosynthesis of Ruminococcin A, a Lantibiotic Produced by a Ruminococcus gnavus Strain from a Human Intestinal Microbiota

Journal of Bacteriology ◽

10.1128/jb.184.1.18-28.2002 ◽

2002 ◽

Vol 184 (1) ◽

pp. 18-28 ◽

Cited By ~ 35

Author(s):

Ana Gomez ◽

Monique Ladiré ◽

Françoise Marcille ◽

Michel Fons

Keyword(s):

Intestinal Microbiota ◽

Growth Phase ◽

Transcriptional Activation ◽

Biosynthetic Gene Cluster ◽

Proteolytic Processing ◽

Open Reading Frames ◽

Signaling Mechanism ◽

Human Intestinal Microbiota ◽

Complex Signaling

ABSTRACT Ruminococcin A (RumA) is a trypsin-dependent lantibiotic produced by Ruminococcus gnavus E1, a gram-positive strict anaerobic strain isolated from a human intestinal microbiota. A 12.8-kb region from R. gnavus E1 chromosome, containing the biosynthetic gene cluster of RumA, has been cloned and sequenced. It consisted of 13 open reading frames, organized in three operons with predicted functions in lantibiotic biosynthesis, signal transduction regulation, and immunity. One unusual feature of the locus is the presence of three almost identical structural genes, all of them encoding the RumA precursor. In order to determine the role of trypsin in RumA production, the transcription of the rum genes has been investigated under inducing and noninducing conditions. Trypsin activity is needed for the growth phase-dependent transcriptional activation of RumA operons. Our results suggest that bacteriocin production by R. gnavus E1 is controlled through a complex signaling mechanism involving the proteolytic processing of a putative extracellular inducer-peptide by trypsin, a specific environmental cue of the digestive ecosystem.

Download Full-text

USING BIOPHOTONICS TO STUDY SIGNALING MECHANISMS IN A SINGLE LIVING CELL

International Journal of Modern Physics B ◽

10.1142/s0217979207045268 ◽

2007 ◽

Vol 21 (23n24) ◽

pp. 4091-4103

Author(s):

DONALD C. CHANG

Keyword(s):

Living Cell ◽

Life Science ◽

Dynamic Properties ◽

Signaling Proteins ◽

Signaling Mechanism ◽

Signaling Mechanisms ◽

Single Living Cell ◽

Biophysical Approach ◽

Single Living ◽

Insight Into

To illustrate the power of the biophysical approach in solving important problems in life science, I present here one of our current research projects as example. We have developed special biophotonic techniques to study the dynamic properties of signaling proteins in a single living cell. This study allowed us to gain new insight into the signaling mechanism regulating programmed cell death.

Download Full-text

Heme-Responsive Transcriptional Activation of Bordetella bhu Genes

Journal of Bacteriology ◽

10.1128/jb.185.3.909-917.2003 ◽

2003 ◽

Vol 185 (3) ◽

pp. 909-917 ◽

Cited By ~ 48

Author(s):

Carin K. Vanderpool ◽

Sandra K. Armstrong

Keyword(s):

Transcriptional Activation ◽

Gene Activation ◽

Preliminary Evidence ◽

Heme Iron ◽

Respiratory Pathogens ◽

Iron Starvation ◽

Positive Regulation ◽

Signaling Mechanism ◽

Σ Factor ◽

Regulator Genes

ABSTRACT Bordetella pertussis and Bordetella bronchiseptica, gram-negative respiratory pathogens of mammals, possess a heme iron utilization system encoded by the bhuRSTUV genes. Preliminary evidence suggested that expression of the BhuR heme receptor was stimulated by the presence of heme under iron-limiting conditions. The hurIR (heme uptake regulator) genes were previously identified upstream of the bhuRSTUV gene cluster and are predicted to encode homologs of members of the iron starvation subfamily of extracytoplasmic function (ECF) regulators. In this study, B. pertussis and B. bronchiseptica ΔhurI mutants, predicted to lack an ECF σ factor, were constructed and found to be deficient in the utilization of hemin and hemoglobin. Genetic complementation of ΔhurI strains with plasmid-borne hurI restored wild-type levels of heme utilization. B. bronchiseptica ΔhurI mutant BRM23 was defective in heme-responsive production of the BhuR heme receptor; hurI in trans restored heme-inducible BhuR expression to the mutant and resulted in BhuR overproduction. Transcriptional analyses with bhuR-lacZ fusion plasmids confirmed that bhuR transcription was activated in iron-starved cells in response to heme compounds. Heme-responsive bhuR transcription was not observed in mutant BRM23, indicating that hurI is required for positive regulation of bhu gene expression. Furthermore, bhuR was required for heme-inducible bhu gene activation, supporting the hypothesis that positive regulation of bhuRSTUV occurs by a surface signaling mechanism involving the heme-iron receptor BhuR.

Download Full-text

Immune Response and Alveolar Bone Resorption in a Mouse Model of Treponema denticola Infection

Infection and Immunity ◽

10.1128/iai.01004-08 ◽

2008 ◽

Vol 77 (2) ◽

pp. 694-698 ◽

Cited By ~ 32

Author(s):

Song F. Lee ◽

Elisoa Andrian ◽

Elden Rowland ◽

Ignacio Christian Marquez

Keyword(s):

Immune Response ◽

Bone Resorption ◽

Alveolar Bone ◽

Interleukin 10 ◽

Oral Infection ◽

Infection Model ◽

Treponema Denticola ◽

Outer Sheath ◽

Oral Inoculation ◽

Animal Infection

ABSTRACT Treponema denticola is considered to be an agent strongly associated with periodontal disease. The lack of an animal infection model has hampered the understanding of T. denticola pathogenesis and the host's immune response to infection. In this study, we have established an oral infection model in mice, demonstrating that infection by oral inoculation is feasible. The presence of T. denticola in the oral cavities of the animals was confirmed by PCR. Mice given T. denticola developed a specific immune response to the bacterium. The antibodies generated from the infection were mainly of the immunoglobulin G1 subclass, indicating a Th2-tilted response. The antibodies recognized 11 T. denticola proteins, of which a 62-kDa and a 53-kDa protein were deemed immunodominant. The two proteins were identified, respectively, as dentilisin and the major outer sheath protein by mass spectrometry. Splenocytes cultured from the infected mice no longer produced interleukin-10 and produced markedly reduced levels of gamma interferon relative to those produced by naïve splenocytes upon stimulation with T. denticola. Mandibles of infected mice showed significantly greater bone resorption (P < 0.01) than those of mock-infected controls.

Download Full-text