Several members of the Flaviviridae family are major pathogens of humans including dengue (DEN), yellow fever (YF), tick-borne encephalitis (TBE), Murray valley encephalitis (MVE), Japanese encephalitis (JE), and hepatitis C virus (HCV). An Australian flavivirus Kunjin (KUN), however, appears to be naturally attenuated and does not cause an overt disease in humans. In contrast, genetically and antigenically closely related to KUN, New York strain of West Nile virus (NY WN) has already caused ~50 ....Several members of the Flaviviridae family are major pathogens of humans including dengue (DEN), yellow fever (YF), tick-borne encephalitis (TBE), Murray valley encephalitis (MVE), Japanese encephalitis (JE), and hepatitis C virus (HCV). An Australian flavivirus Kunjin (KUN), however, appears to be naturally attenuated and does not cause an overt disease in humans. In contrast, genetically and antigenically closely related to KUN, New York strain of West Nile virus (NY WN) has already caused ~500 deaths and over 20,000 registered infections since its emergence in North America in 1999, including 223 deaths and 9122 infections in 2003 alone. Recent studies with DEN indicated that flaviviruses may interfere with early steps of IFN-signalling pathway. The type I Interferon (IFN) response is the first line of defence against viral infections and many viruses have developed different strategies to counteract this response in order to ensure their survival in the infected host. In this grant we seek to exploit our extensive understanding of the molecular biology of KUN virus and the contrasting behaviour of KUN and NY WN viruses to gain an understanding of the role of flavivirus-mediated suppression of host anti-viral IFN response in virus-host relationships and its importance in determining virus virulence.Read moreRead less
Cellular Microenvironments Facilitating The Replication And Propagation Of Flaviviruses
Funder
National Health and Medical Research Council
Funding Amount
$505,279.00
Summary
Flaviviruses are the agents of many mosquito-transmitted infections and many deaths globally each year. The emerging virus West Nile virus (strain New York) is a member of this virus family and shares 99% amino acid homology with the endemic Australian virus Kunjin virus. During virus growth in cells, cellular membrane structures are induced or rearranged by these viruses for their own purpose. That being the production of more virus particles for reinfection of other cells. Using Kunjin virus a ....Flaviviruses are the agents of many mosquito-transmitted infections and many deaths globally each year. The emerging virus West Nile virus (strain New York) is a member of this virus family and shares 99% amino acid homology with the endemic Australian virus Kunjin virus. During virus growth in cells, cellular membrane structures are induced or rearranged by these viruses for their own purpose. That being the production of more virus particles for reinfection of other cells. Using Kunjin virus as a model, and advanced techniques in biochemistry and electron microscopy, we have identified for the first time these membrane structures as the apparent sites of replication of the viral RNA or genetic material, and of the viral proteins involved. We have also observed how new virus particles are able to get out of infected cells and shown how some drugs can prevent this occurring thus limiting their transmission. This research will focus on how the membrane structures are formed in infected cells. The research will determine what cellular components are required by the virus to help it propagate. In particular specific cellular proteins and membrane components that are captured by the virus and moved to different sites in the infected cells. These apparent requirements could possibly lead us to a greater understanding of the complex interactions that occur between the invading virus and the host cells. We aim to directly visualize the process of infection within living cells using new and innovative microscopic techniques. Another of our objectives is to determine the effects of infection on normal cells. The question being whether flavivirus infection disrupts normalcell fuctions like secretion etc. An understanding of these processes, and how the viral RNA is copied into new RNA for more virus particles, will assist in the development of antiviral drugs for treatment of this pathogenic group of viruses.Read moreRead less
Roles Of Virus-integrin Interactions And Rotavirus Modulation Of Host Cell Responses In Viral Pathogenesis
Funder
National Health and Medical Research Council
Funding Amount
$474,000.00
Summary
Rotaviruses are the main cause of severe gastroenteritis in children, and cause 1 in 27 Australian children under the age of 5 years to spend time in hospital. There is currently no rotavirus vaccine available. We aim to discover how rotavirus interacts with host cells. This information is necessary to formulate a safe and effective vaccine, or a therapeutic agent that can block virus growth in host cells. Previously, we showed that rotavirus attaches to cells and enters them using several membe ....Rotaviruses are the main cause of severe gastroenteritis in children, and cause 1 in 27 Australian children under the age of 5 years to spend time in hospital. There is currently no rotavirus vaccine available. We aim to discover how rotavirus interacts with host cells. This information is necessary to formulate a safe and effective vaccine, or a therapeutic agent that can block virus growth in host cells. Previously, we showed that rotavirus attaches to cells and enters them using several members of the integrin protein family that are present on the surface of the cells. Integrins are critical for cell adhesion, survival and communication. In this project, we will identify how rotavirus usage of integrins modulates cell functions. This will help us understand how rotavirus causes disease, how virus spreads in the body and how the immune response defends us from rotavirus. Rotavirus binds integrins using particular stretches of protein sequence that we have shown are also present in other human viral pathogens that cause hepatitis, AIDS and measles. We will determine if these other viruses also recognize integrins.Read moreRead less
Clearing Chronic Infectious Diseases – Enhancing Host Immune Effector Function
Funder
National Health and Medical Research Council
Funding Amount
$92,314.00
Summary
Chronic infections produced by pathogens such as HIV, overwhelm our immune system leading to an exhausted state where cells responsible for the clearance of invading microorganisms are unable to respond effectively. We have recently identified a highly promising therapeutic target that enhances immune effector function. We seek to understand the underlying mechanism, and to explore the therapeutic potential of this approach for the treatment of a broad range of pathogens, including those respons ....Chronic infections produced by pathogens such as HIV, overwhelm our immune system leading to an exhausted state where cells responsible for the clearance of invading microorganisms are unable to respond effectively. We have recently identified a highly promising therapeutic target that enhances immune effector function. We seek to understand the underlying mechanism, and to explore the therapeutic potential of this approach for the treatment of a broad range of pathogens, including those responsible for chronic disease.Read moreRead less
Functions Of Viral Chemokine Receptor Homologues Important For Cytomegalovirus Pathogenesis And Latency
Funder
National Health and Medical Research Council
Funding Amount
$461,597.00
Summary
Cytomegalovirus (CMV) causes life-threatening disease in babies, transplant recipients and HIV-AIDS patients. We will focus on a CMV gene that has been 'hijacked' from the host cell and enables the virus to switch on signalling molecules within infected cells. We will determine how these signals enable CMV to infect sites of the body that are critical for virus transmission and contribute to long-term virus persistence. Our results will provide new strategies for drugs against CMV.
The Role Of The Inflammasome In Modulating Disease During Influenza Virus Infection
Funder
National Health and Medical Research Council
Funding Amount
$616,979.00
Summary
Highly pathogenic influenza A virus (IAV) infections in humans are associated with high mortality rates. This project will provide global and fundamental insights into our understanding of why IAV often cause fatal disease. It will advance knowledge of the mechanisms by which the host and virus interact and elucidate how the host's immune system responds to the infection and modulates disease, to facilitate the development of improved treatments for severe IAV infections.
Determination Of The Mechanisms Of Action Of A Cytomegalovirus Chemokine Receptor Homologue In Pathogenesis
Funder
National Health and Medical Research Council
Funding Amount
$251,341.00
Summary
A number of herpesviruses encode proteins that are similar to proteins of our immune system. These pirated proteins are exploited by the virus to enable it to replicate and persist in the infected individual, usually by evading or gaining advantage from the normal immune response. This project will investigate the role of one such protein found in both human and animal herpesviruses (specifically cytomegaloviruses (CMV)) that is conserved with cellular cell surface proteins (receptors) that bind ....A number of herpesviruses encode proteins that are similar to proteins of our immune system. These pirated proteins are exploited by the virus to enable it to replicate and persist in the infected individual, usually by evading or gaining advantage from the normal immune response. This project will investigate the role of one such protein found in both human and animal herpesviruses (specifically cytomegaloviruses (CMV)) that is conserved with cellular cell surface proteins (receptors) that bind immune signaling molecules (chemokines). Chemokines are important proteins in the early response to infection. Binding of chemokines to their receptors initiates a cascade of signals within the cell that has profound effects on cellular responses to environmental stimuli. Thus, it is believed that herpesviruses have acquired chemokine receptors to modify or react to the immune response, causing infected cells to behave abnormally either despite or in response to chemokine signals. This project will determine how this CMV specific protein affects the function of cells that CMV infects and how this may promote virus replication, dissemination and persistence in infected hosts. We will also engineer CMVs where the activity of the target protein can be inhibited by administration of prototype antiviral drugs. If inhibition of the activity of the protein is found to reduce virus replication, dissemination or persistence, then this will demonstrate that this type of protein would be a suitable target for the development of novel drugs active against CMV infections. CMV can cause serious (potentially life threatening) disease in newborn children (following infection in the uterus) and immunosuppressed people (eg. organ transplant recipients and people with HIV-AIDS). Our studies will improve our understanding of the contribution of a specific CMV protein to disease, thereby assisting efforts to reduce the impact of CMV infections.Read moreRead less
The Role Of Noncoding Viral RNAs In Flavivirus Infection And Exosomal Signalling
Funder
National Health and Medical Research Council
Funding Amount
$683,447.00
Summary
The application is aimed at investigating the novel role for viral noncoding RNAs in exosomal antiviral signalling and associated outcome of infection with West Nile virus. We will identify host enzymes involved in generation of viral noncoding RNAs, determine which host proteins they interact with and how these interactions determine their incorporation into secreted exosomes to influence outcome of infection.
NEW INSIGHT INTO GLYCAN REQUIREMENTS FOR ROTAVIRUS-CELL ATTACHMENT AND ENTRY
Funder
National Health and Medical Research Council
Funding Amount
$1,068,758.00
Summary
Rotavirus causes significant infection and loss of life in children, particularly in underdeveloped countries. This project will investigate the role of carbohydrates as contact points for this deadly virus towards the goal of developing novel vaccines and drug therapies.