Transposable Element Mobility And Chromosomal Rearrangement In The Fungal Pathogen Cryptococcus During Human Infection
Funder
National Health and Medical Research Council
Funding Amount
$322,028.00
Summary
Pathogenic fungi present in the environment have emerged as an increasingly common threat to human health. Cryptococcus neoformans and the closely related species Cryptococcus gattii are the leading causes of life-threatening fungal meningitis, and Australia is one of the few countries where both species are prevalent. Although C. neoformans is an increasingly common cause of infection in immunocompromised patients such as those suffering from AIDS, approximately one in four infected individuals ....Pathogenic fungi present in the environment have emerged as an increasingly common threat to human health. Cryptococcus neoformans and the closely related species Cryptococcus gattii are the leading causes of life-threatening fungal meningitis, and Australia is one of the few countries where both species are prevalent. Although C. neoformans is an increasingly common cause of infection in immunocompromised patients such as those suffering from AIDS, approximately one in four infected individuals has no apparent immune system defect. For patients with AIDS, in the absence of antiretroviral therapy cryptococcal infection is incurable and requires lifelong treatment with antifungal medication to keep the infection in check. During infection, Cryptococcus is under tremendous stress enforced not only by the immune system and the presence of antifungals, but also by the high temperature, nutrient limiting environment encountered in the host. The proposed research will reveal how Cryptococcus evolves in this environment to enable persistence of infection despite medical intervention. I propose that naturally occurring mobile genetic elements present in the Cryptococcus genome cause chromosomal rearrangements during long term infection to produce gene deletions and duplications that facilitate survival. By characterising these changes and the genes associated with them, the research will identify novel genes involved in pathogenesis and will increase our understanding of the infection process. The expected outcome of this project is a detailed understanding of the roles mobile element movement and chromosomal rearrangement play in Cryptococcus during infection, and how these affect genes that contribute to the pathogenic process. The fundamental knowledge gained from this study will facilitate studies designed to combat infections in the clinical setting, provide new drug targets and help foster the development of more effective therapies.Read moreRead less
The fungal pathogen Cryptococcus neoformans is responsible for up to a million deaths annually, necessitating the development of novel antifungals. We have characterised the GTP biosynthesis enzyme IMP dehydrogenase, revealing it is critical for infection, and structural and functional analysis reveals routes to inhibitor specificity. In the proposed work will develop novel antifungal compounds that target this enzyme, as well as investigate related enzymes as potential future drug targets.
The pathogen Cryptococcus neoformans is responsible for hundreds of thousands of deaths annually. If the infection is survived, relapse caused by evolved forms of the original infecting strain is common. Our research has uncovered similar genetic changes in isolates from unrelated patients that implicate epigenetic processes in relapse and reveal potential vulnerabilities of the pathogen. The proposed work is to investigate these changes to assist in our antifungal drug development efforts.
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
Novel Antifungal Strategies Using Drug Response Networks
Funder
National Health and Medical Research Council
Funding Amount
$484,420.00
Summary
Fungal cells are quite similar to our own making it hard to find good drug targets. This project aims to enhance current antifungal drugs with agents that interfere with iron, which is needed for fungal growth. We will see how fungal cells change the genes they use when they are treated with drugs alone and combined with molecules that mop up iron. We will then track the pathways within cells that are targets of the affected genes, and find points where these pathways can be blocked.
Cryptococcal Meningoencephalitis - Fungal Determinants Of Invasion Of The CNS
Funder
National Health and Medical Research Council
Funding Amount
$587,634.00
Summary
Meningitis and brain infection (meningoencephalitis) due to the fungus Cryptococcus, affect over 1 million patients with AIDS annually, especially in developing countries; with more than 600,000 deaths. It is not known how Cryptococci cross from the blood stream into the brain; this must be elucidated in order to prevent and/or control this devastating infection. This project will determine how cryptococci influence host blood cells to act as “Trojan horses” and/or release products that initiate ....Meningitis and brain infection (meningoencephalitis) due to the fungus Cryptococcus, affect over 1 million patients with AIDS annually, especially in developing countries; with more than 600,000 deaths. It is not known how Cryptococci cross from the blood stream into the brain; this must be elucidated in order to prevent and/or control this devastating infection. This project will determine how cryptococci influence host blood cells to act as “Trojan horses” and/or release products that initiate invasion of brain tissue and meningitis.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.
Signalling Pathways And Fungal Virulence – The Inositol Polyphosphate Kinase Pathway In Cryptococcus Neoformans
Funder
National Health and Medical Research Council
Funding Amount
$545,189.00
Summary
Bloodstream fungal infections kill millions of people per year world-wide and are costly to treat. A potentially fruitful strategy for developing new, urgently-needed drugs to fight these infections, is to target signalling pathways, which in fungi, are essential for establishing infection. This proposal investigates how one such pathway, the inositolpolyphosphate kinase pathway, allows fungi to establish infection and will determine which components are suitable targets for drug development.
Fungi are increasingly causing life-threatening infections. Little is known about the mechanisms underlying these infections. We will compare the genomes of high and low virulent fungal strains to gain insides into the basis of these differences by using C. gattii as model of a globally highly pathogenic fungus. The findings will be generalized by comparing the obtained results with the genomes of other important pathogenic fungi to develop a scientific basis for better treatment strategies.