Characterization Of A Novel Secretion And Attachment System Necessary For The Formation Of A Virulence Coat In Porphyromonas Gingivalis
Funder
National Health and Medical Research Council
Funding Amount
$828,857.00
Summary
In this study we will characterize a novel bacterial secretion system that we have discovered. This system mediates the secretion of proteins from the bacterial cell and their attachment to the cell surface. This system is essential for the virulence of a bacterium associated with severe gum disease. The chacterization of this system may offer opportunities for the development of new treatments to target this disease.
The Role Of Porphyromonas Gingivalis Outer Membrane Vesicle Biogenesis In Virulence And Immunomodulation
Funder
National Health and Medical Research Council
Funding Amount
$734,288.00
Summary
Porphyromonas gingivalis is a keystone pathogen in chronic periodontitis. This bacterium exists as part of a biofilm on the surface of the tooth and selectively packages enzymes, toxins and antigens on to vesicles that penetrate host tissue and cause the inflammatory response that is associated with disease progression. In this study we will determine the host response to vesicles and determine the role of a specific protein in vesicle biogenesis.
Polymicrobial Interactions In Chronic Periodontitis
Funder
National Health and Medical Research Council
Funding Amount
$413,133.00
Summary
In this study we will determine how three pathogenic species of bacteria interact. Together these species are associated with periodontitis and they produce toxic compounds that may cause tissue damage. Using the newly emerging technologies of metabolomics and transcriptomics we will characterise these interactions. This will identify potential diagnostic biomarkers of disease and therapeutic targets.
Regulation Of Porphyromonas Gingivalis Gene Expression
Funder
National Health and Medical Research Council
Funding Amount
$531,696.00
Summary
Chronic periodontitis (gum disease) is a chronic inflammatory disease of the supporting tissues of the teeth associated with bacteria that results in the destruction of tooth support and can ultimately lead to tooth loss. The disease is a major public health problem with a large economic burden and has been associated with an increased risk of cardiovascular disease. The bacterium Porphyromonas gingivalis is recognized as the major causative pathogen in the development of chronic periodontitis. ....Chronic periodontitis (gum disease) is a chronic inflammatory disease of the supporting tissues of the teeth associated with bacteria that results in the destruction of tooth support and can ultimately lead to tooth loss. The disease is a major public health problem with a large economic burden and has been associated with an increased risk of cardiovascular disease. The bacterium Porphyromonas gingivalis is recognized as the major causative pathogen in the development of chronic periodontitis. This bacterium is part of subgingival dental plaque, a biofilm attached to the surface of the tooth below the gum line, and releases a range of proteins and cytotoxic agents that cause damage to the tooth's supporting tissues both directly and indirectly through the dysregulation of the host's immune response. To cause disease this bacterium must be able to grow as a biofilm and withstand the immune response of the host. Detailed knowledge of how this bacterium is able to establish and proliferate in subgingival plaque, tolerate the oxidative attack and elevated temperatures that are part of the immune response and obtain the essential micronutrient iron will provide new targets for the development of specific inhibitors that may have utility as an adjunctive therapeutic for the control of chronic periodontitis. We will use a state of the art DNA microarray analysis to determine the proteins that regulate genes associated with the virulence of this bacterium. The insights we gain from this study will have broader application for the understanding of human disease that is caused by bacteria that grow as biofilms on various surfaces of the human body.Read moreRead less
Characterisation Of A Novel Porphyromonas Gingivalis Regulatory Protein That Controls Virulence Related Gene Expression
Funder
National Health and Medical Research Council
Funding Amount
$569,620.00
Summary
In this study we will characterise the manner in which genes essential for the virulence of Porphyromonas gingivalis, a bacterium associated with chronic periodontitis, are regulated. This will provide information on how this bacterium causes disease and may offer opportunities for the development of new treatment strategies.
Characterization Of A Novel Secretion System Necessary For Porphyromonas Gingivalis Virulence.
Funder
National Health and Medical Research Council
Funding Amount
$596,412.00
Summary
In this study we will characterize a novel bacterial secretion system that we have discovered. This sytem mediates the secretion of proteins from the bacterial cell and their attachment to the cell surface. This system is essential for the virulence of Porphyromonas gingivalis, a bacterium associated with chronic periodontitis. The chacterization of this system may offer opportunities for the development of new treatments to target this disease.
The RgpA-Kgp Proteinase-adhesin Complex And Virulence Of Porphyromonas Gingivalis
Funder
National Health and Medical Research Council
Funding Amount
$527,310.00
Summary
Periodontitis is a bacterial-associated inflammatory disease of the supporting tissues of the teeth which can result in tooth loss. The disease is a major public health problem with a large economic burden. A bacterium Porphyromonas gingivalis has now been identified as a major causative agent of chronic periodontitis. We have identified a major virulence factor of P. gingivalis. This virulence factor is a complex of proteins, encoded by two genes, and is involved in binding and destruction of h ....Periodontitis is a bacterial-associated inflammatory disease of the supporting tissues of the teeth which can result in tooth loss. The disease is a major public health problem with a large economic burden. A bacterium Porphyromonas gingivalis has now been identified as a major causative agent of chronic periodontitis. We have identified a major virulence factor of P. gingivalis. This virulence factor is a complex of proteins, encoded by two genes, and is involved in binding and destruction of host tissue. When used as a vaccine in animal models the protein complex protects against P. gingivalis infection. Animal protective sera recognises a segment of the protein complex involved in binding to host substrates. The aim of this project is to continue this work on the characterisation of this complex and its role in virulence in an approach to ultimately develop a defined vaccine against P. gingivalis based on this protein complex, in particular the sequences involved in binding. The expected outcome of this research is the further biochemical characterisation of the RgpA-Kgp protein complex and its role in virulence as well as development of a defined vaccine prepared using recombinant DNA and chemical synthesis techniques that protects against P. gingivalis infection in animal models of disease.Read moreRead less
Polymicrobial Pathogenesis In A Murine Periodontitis Model.
Funder
National Health and Medical Research Council
Funding Amount
$235,500.00
Summary
Severe periodontal disease is a chronic inflammatory disease of the tooth's supporting tissues and is associated with specific pathogenic bacteria. The disease has a large economic burden and is a major public health problem. Three bacterial species have recently been shown to be closely associated with advanced periodontal disease in humans. One of these three bacterial species has been shown to produce periodontal disease in a mouse model of disease and the major proteins on the cell surface o ....Severe periodontal disease is a chronic inflammatory disease of the tooth's supporting tissues and is associated with specific pathogenic bacteria. The disease has a large economic burden and is a major public health problem. Three bacterial species have recently been shown to be closely associated with advanced periodontal disease in humans. One of these three bacterial species has been shown to produce periodontal disease in a mouse model of disease and the major proteins on the cell surface of this bacterium have been characterized. Further, in this mouse model it has been demonstrated that killed cells of the bacterium or the major surface proteins when used as a vaccine prevent development of disease. The purpose of the current proposal is to extend this work to include all three bacterial species that have been associated with disease in humans. The major surface proteins of all these bacterial species when grown together as high density polymicrobial complexes will be determined. Recent results have shown that in high-density, polymicrobial cultures bacteria communicate using signalling systems which can alter the expression of cell surface proteins associated with disease. The ability of the three bacterial species, when grown in polymicrobial culture, to cause periodontal disease in the mouse model will be determined. This will allow the determination of whether a single species and-or multispecies vaccine is capable of protecting against disease in this model. The significance of the work is that it will increase our understanding of the bacteria associated with periodontal disease and it may lead to the development of an effective vaccine to help prevent disease in humans.Read moreRead less
Porphyromonas Gingivalis Cysteine Proteinases In Modulation Of Cell-mediated Immune Response In Periodontitis
Funder
National Health and Medical Research Council
Funding Amount
$228,000.00
Summary
Chronic inflammatory diseases of the tissues supporting the teeth comprise some of the most widespread and common diseases to affect mankind. Recent research has indicated the major contributor to the most common form of destructive periodontal disease is the bacterium Porphyromonas gingivalis. This organism produces powerful enzymes which overcome the body's attempts to neutralise them. It is also known that the destructive phase of the disease is characterised by a change in the behaviour of t ....Chronic inflammatory diseases of the tissues supporting the teeth comprise some of the most widespread and common diseases to affect mankind. Recent research has indicated the major contributor to the most common form of destructive periodontal disease is the bacterium Porphyromonas gingivalis. This organism produces powerful enzymes which overcome the body's attempts to neutralise them. It is also known that the destructive phase of the disease is characterised by a change in the behaviour of the immune system cells which accumulate in the diseased tissues. This is manifest as a loss of protective immunity and replacement by ineffective or even tissue damaging responses. Critical in directing the pattern of behaviour of the immune system cells are the potent messenger molecules or cytokines which pass between cells. We have demonstrated that the bacterial proteinases can destroy a critical messenger molecule that instructs the defensive phagocytic cells to attack bacteria. These cells in return normally send a powerful signal back to the controlling T lymphocyte to amplify the protective signals. Associated bacterial molecules stimulate more secretion of messenger molecules which are paradoxically destroyed by the bacterial enzymes. This could cause chaos in the local tissue environment. Further, the bacterial proteinases can also eliminate some important surface molecules of T lymphocyte that are important in the activation process. The effect of this could produce impairment of T lymphocyte at periodontal sites. The planned research will define how the proteinases modulate T lymphocyte immune response. Further, the relation between the capacity of the bacterial enzymes to disrupt the vascular cells and the progression of periodontitis will also be determined.Read moreRead less