Inhibition Of Interferon-alpah-beta By Chikungunya Virus And The Induction Of Arthritis
Funder
National Health and Medical Research Council
Funding Amount
$709,193.00
Summary
Chikungunya virus is a mosquito borne virus which has caused epidemics of arthritis around the world (recently 260,000 people Reunion Island, France and 1.6 million people in India). The virus is ordinarily very sensitive to the main mammalian anti-viral defence system (interferon alpha-beta). This grant seeks to understand how, despite the activation of this system during infection, the virus manages to persist and cause 3-6 months of debilitating arthritis.
Control Of Viral Replication By Non-coding Viral RNA
Funder
National Health and Medical Research Council
Funding Amount
$502,270.00
Summary
In 25 years since identified, HIV-AIDS deaths have exceeded 30 million and 40 million more are now living with HIV. The toll will soon far surpass any other infectious disease epidemic in history, or even military deaths from war in the past century. While effective combination drug therapies are available, multi-drug resistant HIV strains are commonly transmitted, leaving some patients with limited treatment options. New classes of drugs aimed at different steps in virus replication are urgentl ....In 25 years since identified, HIV-AIDS deaths have exceeded 30 million and 40 million more are now living with HIV. The toll will soon far surpass any other infectious disease epidemic in history, or even military deaths from war in the past century. While effective combination drug therapies are available, multi-drug resistant HIV strains are commonly transmitted, leaving some patients with limited treatment options. New classes of drugs aimed at different steps in virus replication are urgently needed. We have discovered that viral RNAs that do not code for protein serve important functions in HIV replication. We will study the molecular mechanisms these non-coding (intron) RNAs previously considered junk use to support of HIV gene expression and assess their potential as drug targets. First, we will investigate the role of these junk RNA loops, or lariat introns, produced in large amounts during the HIV replication cycle. Retroviruses employ RNA splicing to make mRNA for envelope and regulatory accessory genes. The complex alternative RNA splicing pattern of HIV spawns several non-coding lariats, including the lariat-intron that contains much of the removed env coding sequence. We have made the counterintuitive finding that the env-lariat dramatically enhances expression of Env protein. We will examine how this occurs and the involvement of the new class of gene-expression controlling micro-RNAs in this process. We will test for functional activity from the other lariat-introns that are produced by HIV. Second, we will characterise the mRNA-element required for efficient expression of the HIV envelope glycoprotein, Env gp160, which is essential for virus binding and entry during infection. This RNA-element directs the cell protein translation machinery to commence protein synthesis at the start of the Envgp160 rather than at upstream start sites for Vpu and Rev. We will determine how this RNA element works, its structure, and how it might be inactivated.Read moreRead less
Respiratory Syncytial Virus Matrix Protein-Host Protein Interactions As Targets For Therapeutics
Funder
National Health and Medical Research Council
Funding Amount
$686,885.00
Summary
Respiratory syncytial virus (RSV) causes more deaths in winter than influenza, being the major cause of viral pneumonia in infants worldwide, and a potent lower respiratory pathogen in the elderly and immunosuppressed adults. The present proposal will apply a range of techniques to search for new inhibitors of viral infection which target host-virus interactions, as the first step towards new generation anti-viral agents to treat RSV infection.
Even in well-resourced countries, the ability to continue treating HIV patients for their lifetime may become unaffordable, which has focused attention on developing a cure for HIV. We have exploited unique insights into a pathway for Tat expression from latent HIV to identify novel compounds that target HIV latency. This project assembles a multidisciplinary team to optimize the lead compounds, and develop novel drug regimens to fast-track into clinical development as a HIV-curative therapy.
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
Immunopathogenesis Of Varicella Zoster Virus Infection
Funder
National Health and Medical Research Council
Funding Amount
$346,250.00
Summary
Varicella zoster virus (VZV) is a herpesvirus which infects up to 90% of the population. VZV causes chicken pox (varicella) predominantly in childhood and shingles (herpes zoster) in middle to old age people. Whilst VZV usually causes relatively mild disease in healthy individuals, VZV still causes significant morbidity in children and adults. VZV causes life-threatening disease in immunocompromised individuals such as patients who are elderly or have HIV disease. Shingles affects many elderly i ....Varicella zoster virus (VZV) is a herpesvirus which infects up to 90% of the population. VZV causes chicken pox (varicella) predominantly in childhood and shingles (herpes zoster) in middle to old age people. Whilst VZV usually causes relatively mild disease in healthy individuals, VZV still causes significant morbidity in children and adults. VZV causes life-threatening disease in immunocompromised individuals such as patients who are elderly or have HIV disease. Shingles affects many elderly individuals and a major complication is prolonged severe pain or post-herpetic neuralgia (PHN), which can be severely debilitating and often requires follow-up medical care for months or even years after the initial attack. Despite its significant impact on the community, little is known about how this virus functions and causes disease. This project aims to improve our understanding of how VZV infection affects specialised human cells in order to provide novel information for the development of therapies aimed at lessening the impact of VZV disease on the community. This project has four components: (1) We will continue studies which have shown that VZV causes programmed cell death (apoptosis) in human skin cells (fibroblasts) but not human nerve cells (neurons). We aim to identify viral genes responsible for the cell-type specific modulation of apoptosis in human neurons and fibroblasts (2) We will examine human sensory ganglia (clusters of human nerve cells) during shingles and determine what immune cells are present and whether neurons are undergoing apoptosis (3) To assess the impact of VZV infection on the ability of specialized immune cells (called dendritic cells) to mature properly (4) We have shown that VZV may actively avoid immune detection by interfering with the function of dendritic cells. We aim to identify the mechanism responsible for the virus interfering with the expression of immune molecules which are essential for our immune system.Read moreRead less
Discovery Of A Novel Immune Evasion Strategy Employed By Mosquito Borne Viruses To Suppress Antiviral Immune Responses
Funder
National Health and Medical Research Council
Funding Amount
$418,642.00
Summary
The transition from mosquitoes, ticks, or other invertebrate vectors to the human hosts represents a crucial step in the successful establishment of arthropod borne viruses (arboviruses). The incidence of arbovirus infections such as dengue virus, West Nile virus, Ross River virus is increasing at an alarming rate in various parts of the world. In addition, the emergence of new viruses resulting in significant mortality in the population is of utmost concern. Vaccines for many of these viruses r ....The transition from mosquitoes, ticks, or other invertebrate vectors to the human hosts represents a crucial step in the successful establishment of arthropod borne viruses (arboviruses). The incidence of arbovirus infections such as dengue virus, West Nile virus, Ross River virus is increasing at an alarming rate in various parts of the world. In addition, the emergence of new viruses resulting in significant mortality in the population is of utmost concern. Vaccines for many of these viruses remain elusive. One factor that contributes to this is the ability of viruses to develop ingenious strategies to avoid or suppress the host defence systems, which enable its successful establishment in the host. Understanding how viruses evade-suppress host defence machinery will certainly enhance and improve our approaches to fight them. For the first time internationally we have discovered a new and novel pathway employed by arboviruses to suppress antiviral immune responses in the host. We have discovered that naturally occurring carbohydrates on viruses derived from mosquito cells, would influence these virus s ability to evade-suppress host antiviral proteins such as interferons. This may be a general effect of arboviruses or may even extend to other viruses , which include a number of deadly pathogens (HIV, Influenza). This research has the potential to significantly expand our understanding of how these viruses establish infection and cause disease. Also this discovery has broader implications for understanding inflammatory processes and their regulation.Read moreRead less
Herpesviruses infect most Australians and cause recurrent ulcers, birth defects and cancer. Infection lasts lifelong, and spreads to close contacts without obvious clinical signs. Thus disease is hard to prevent. However we can learn much from related animal infections. We have shown that both mouse and human herpesviruses enter mice via cells in the nose. Thus human infections might follow the same route. We will define what body defences work here and whether vaccines can prevent infection.
Human ?-herpesviruses persist for life, cause cancers and emerge with particular virulence when the immune system is weak. Vaccination against them is therefore an important health priority. We have shown for a related ?-herpesvirus of mice that live vaccines protect. Antibody seems to play a major role. We will test whether safer, recombinant vaccines are also sufficient to elicit protective antibody. Thus we can establish a viable strategy for preventing virus-induced human cancers.