Regulation Of Secretion Of The Fungal Virulence Determinant, Phospholipase B
Funder
National Health and Medical Research Council
Funding Amount
$487,500.00
Summary
Serious systemic infections due to fungi have increased dramatically in the past few years, especially in people with poorly functioning immune systems. Treatment of these conditions is problematic because the few drugs which are available are not highly effective, and-or cause significant side-effects. Little is understood of how fungi cause disease, and this problem must be addressed if these infections are to be contained. We have discovered that the enzyme, phospholipase B (PLB), is secreted ....Serious systemic infections due to fungi have increased dramatically in the past few years, especially in people with poorly functioning immune systems. Treatment of these conditions is problematic because the few drugs which are available are not highly effective, and-or cause significant side-effects. Little is understood of how fungi cause disease, and this problem must be addressed if these infections are to be contained. We have discovered that the enzyme, phospholipase B (PLB), is secreted by the disease-causing fungus, Cryptococcus neoformans, and that it is important in enabling the fungus to invade the host's cells and spread around the body from the lungs to the brain, where it can cause meningoencephalitis. PLB is also produced by other disease-causing fungi. The mechanism of PLB secretion is completely unknown. In this project we aim to determine the pathways involved in PLB secretion with the intention of exploiting steps unique to pathogenic fungi, for the future design of new anti-fungal drugs.Read moreRead less
Invasive fungal infections are a serious, escalating health issue. They cause severe disease with high death rates and are very costly to the health system. Current drugs often have suboptimal efficacy and cause side effects. New drugs are needed urgently. Many fungi, including the AIDS-related pathogen, Cryptococcus neoformans, secrete phospholipase B (Plbp) to facilitate infection. We will identify and investigate the Plbp secretion pathway as a novel anti-fungal drug target.
Cryptococcal Phospholipases: Structure, And Potential Targets For Therapeutics
Funder
National Health and Medical Research Council
Funding Amount
$511,650.00
Summary
Mortality and morbidity from invasive fungal infections have increased substantially over the past two decades, especially in immunocompromised patients, such as those with AIDS. Antifungal drugs marketed at present are not very effective or are toxic. There is a need to identify new metabolic and structural targets, some of which are responsible for fungal virulence, as potential areas for development of new drugs. One such virulence factor discovered in our laboratory is an enzyme secreted by ....Mortality and morbidity from invasive fungal infections have increased substantially over the past two decades, especially in immunocompromised patients, such as those with AIDS. Antifungal drugs marketed at present are not very effective or are toxic. There is a need to identify new metabolic and structural targets, some of which are responsible for fungal virulence, as potential areas for development of new drugs. One such virulence factor discovered in our laboratory is an enzyme secreted by the pathogenic fungus, Cryptococcus neoformans, which is acquired by inhalation into the lungs where it can cause lesions, and eventually spreads to other parts of the body, including the brain (median mortality, 17%). This enzyme breaks down cell membranes, aiding invasion into the host lungs and other tissues, and is called phospholipase B (PLB). It is also produced by several other pathogenic fungi, and is different from human phospholipases. In this project we aim to understand how the PLB is constructed, so that we can work out where the cell membrane components bind to it. We will then design drugs which can bind to the PLB enzyme in place of membrane components and in this way block its harmful effects. We will test the effects of such drugs to make sure they do not interfere with human enzyme systems. Inhibitory compounds may also be able to kill the cryptococcal cells, especially if administered together with currently used therapies. Drugs developed to treat Cryptococcus will then be applicable to other systemic fungal infections - a major advance in the treatment of fungal disease, and a saving of some A$60,000 per patient (estimated from a recent U.S. study).Read moreRead less
Fungal Phospholipases: A Novel Drug Discovery Platform
Funder
National Health and Medical Research Council
Funding Amount
$588,679.00
Summary
Invasive fungal infections are a serious and escalating health issue. They cause severe disease with a high death rate and are very costly to the health system. This is especially the case in immunocompromised patients, such as those with blood malignancies, organ transplant recipients and AIDS. The number of currently available drugs for the treatment of fungal infections is limited and they are, in general, either not very effective or toxic. The development of fungal strains resistant to thes ....Invasive fungal infections are a serious and escalating health issue. They cause severe disease with a high death rate and are very costly to the health system. This is especially the case in immunocompromised patients, such as those with blood malignancies, organ transplant recipients and AIDS. The number of currently available drugs for the treatment of fungal infections is limited and they are, in general, either not very effective or toxic. The development of fungal strains resistant to these drugs is also becoming problematic. There is an urgent need to discover and develop new drugs effective against fungal infections through identifying new targets in the fungal cell and-or targets that prevent the spread of infection in the human host. We were the first to describe an enzyme, phospholipase B (PLB1), which is secreted by the medically important fungus, Cryptococcus neoformans, and is important in invasion of human tissue by the fungus. It is also important in remodelling of membranes in the fungal cell. This enzyme is sufficiently different from human phospholipases to be a good target for antifungal drugs. In this project, we aim to synthesise and test molecules which should inhibit the activity of PLB and in this way block its harmful effects. We will test the effects of such drugs to make sure they do not interfere with human enzyme systems. Inhibitory compounds may also be used to kill the fungal cells, especially if administered together with currently used therapies. The design and development of new antifungal drugs with a novel mode of action represents a major advance in the treatment of fungal disease, and a saving of some A$60000 per affected patient (estimated from a recent US study).Read moreRead less
Developing Anti-Inflammatory Drugs Based On Inhibition Of A Human Enzyme
Funder
National Health and Medical Research Council
Funding Amount
$160,000.00
Summary
Human secretory phospholipases A2 have been associated with inflammatory diseases for many years, yet very few truly potent inhibitors of the human enzymes sPLA2 (isoforms IIa, V or X) are known due to a range of problems relating to the lipid nature of substrates, unavailability of enzymes, enzyme assays that do not correlate with in vivo data. Although there remains controversy about which enzyme is responsible in vivo for degrading membrane phospholipids to inflammatory mediators like arachid ....Human secretory phospholipases A2 have been associated with inflammatory diseases for many years, yet very few truly potent inhibitors of the human enzymes sPLA2 (isoforms IIa, V or X) are known due to a range of problems relating to the lipid nature of substrates, unavailability of enzymes, enzyme assays that do not correlate with in vivo data. Although there remains controversy about which enzyme is responsible in vivo for degrading membrane phospholipids to inflammatory mediators like arachidonate, PAF, prostaglandins, leukotrienes, etc. there is a consensus that blockade of phospholipid metabolism would represent a major advance on NSAIDs as antiinflammatory agents. No sPLA2-IIa inhibitor is available yet in man. We aim to create an attractive data package showing proof of concept for a potent new type of antiinflammatory drug. This data will give us an improved negotiating position in our commercialisation of a new drug with potential multi-billion dollar markets as diverse as arthritis, asthma, reperfusion injury, organ transplantation and many other currently intractable human ailmentsRead moreRead less