Silent Mutations In The HIV-1 Reverse Transcriptase Selected During Antiretroviral Therapy
Funder
National Health and Medical Research Council
Funding Amount
$555,325.00
Summary
This project seeks to determine the role of silent mutations in the HIV reverse transcriptase that are selected during drug therapy in HIV infected individuals on HIV fitness, reverse transcriptase function and the emergence of drug resistance. This study will increase our understanding of the mechanisms by which the virus evades the effects of antiretrovirals and will provide a rationale for deciding on the best drug combinations for use in patients infected with specific HIV strains (clades).
Cell Type Specific Biologic Responses To HIV Infection
Funder
National Health and Medical Research Council
Funding Amount
$636,242.00
Summary
The way in which HIV alters the internal environment of its target cells to facilitate its growth will be examined. These changes enhance its ability to gain a toehold in the human body after entering the genital tract and its persistence for life in the brain and elsewhere in the body.
An RNA Element Negatively Regulates Initation HIV-1 Reverse Transcription And Inhibits Proviral Integration
Funder
National Health and Medical Research Council
Funding Amount
$581,524.00
Summary
We recently made the discovery that the virus that causes AIDS can be potently inhibited by stimulating a specific step in the virus life cycle. Our evidence suggests this stimulation is controlled by a host factor which will be identified in this study. Its discovery would be an important step towards a new means to fight HIV infection.
Elucidating The Flexibility Of Coreceptor Engagement By HIV-1 Important For Macrophage Tropism And Escape From Entry Inhibitors
Funder
National Health and Medical Research Council
Funding Amount
$635,506.00
Summary
CCR5 antagonists are a new type of anti-HIV-1 drug that stops the virus from entering cells. We have evidence to suggest that the ability of CCR5 antagonists to function properly is linked to the ability of HIV-1 to infect a type of immune cell called macrophages. In this proposal, we will investigate precisely how HIV-1 enters macrophage cells, and then determine how this may influence the outcome of patients who are receiving these drugs as part of their clinical care.
Elucidating The Mechanism Of Action Of Dendrimer Nanoparticles Against HIV
Funder
National Health and Medical Research Council
Funding Amount
$559,354.00
Summary
Dendrimers are nanoparticles with highly branched structures and they are being developed as topical microbicides to prevent the sexual transmission of HIV. This study will determine how dendrimers block HIV entry into host cells so that we can design more effective inhibitors and microbicides.
Adaptive Changes In HIV-1 Subtype C Envelope Glycoproteins Contributing To Pathogenicity.
Funder
National Health and Medical Research Council
Funding Amount
$427,648.00
Summary
HIV exists as multiple subtypes. The most commonly studied is type B (B-HIV). B-HIV is common in North America, Europe and Asia, but accounts for only a small fraction of HIV infections worldwide. Type C HIV (C-HIV) in Africa and Asia accounts for the majority of infections worldwide, yet very little is known about how C-HIV causes AIDS. We aim to understand how C-HIV causes AIDS. This is critical for development of drugs and vaccines specifically designed for those who are most urgently need.
In Africa, Plasmodium falciparum malaria and HIV infection are devastating health problems, and HIV makes malaria worse, especially in pregnancy. Recently, we showed why this may be. In pregnancy, antibodies to proteins expressed on the surface of malaria infected cells protect against malaria in the placenta. Levels of these antibodies were decreased by HIV infection, and lowest in women with AIDS. Both first-time and experienced mothers lacked antibody. Now we will investigate the function of ....In Africa, Plasmodium falciparum malaria and HIV infection are devastating health problems, and HIV makes malaria worse, especially in pregnancy. Recently, we showed why this may be. In pregnancy, antibodies to proteins expressed on the surface of malaria infected cells protect against malaria in the placenta. Levels of these antibodies were decreased by HIV infection, and lowest in women with AIDS. Both first-time and experienced mothers lacked antibody. Now we will investigate the function of these antibodies. They might block adhesion to placental receptors, decreasing parasite numbers in the placenta. Or they might coat infected red cells, making them targets for phagocytosis (eating) by macrophages (white blood cells). We will examine the effects of HIV on each process, to find out how reduced antibody might affect the pregnant woman. HIV also affects macrophages and related immune cells, monocytes and dendritic cells. We will study how HIV infection in these cells impairs the way they eat malaria cells, and whether it alters the way they become activated and produce infection-fighting proteins when they encounter malaria. Without these proteins, malaria may grow unchallenged. Using our new assays we will study these responses in African women. We will discover whether HIV also affects antibodies to proteins expressed by parasites infecting children, who are at highest risk of malaria. HIV particularly decreases development of antibody to new targets, so children with little malaria experience may lack antibodies to many different proteins. We will find out whether low levels of malaria antibody in children may be the reason why the get more severe malaria. By understanding how HIV affects malaria immunity, we can develop better ways to protect people at risk from malaria. These findings will also be important to work on malaria vaccines. If HIV infected people respond poorly to natural infection, they may also fail to respond to vaccines.Read moreRead less
The Role Of Chemokines In Establishing HIV Latency
Funder
National Health and Medical Research Council
Funding Amount
$372,049.00
Summary
Although antiviral therapy is effective in controlling HIV, therapy must be continued life-long because the virus cannot be cleared from long lived infected CD4+ T cells that are silently or latently infected. In this proposal we will explore the mechanism of how HIV can enter these resting CD4+ T-cells and establish long lived latent infection. Understanding this process may potentially lead to new strategies to cure HIV infection.
Molecular Studies Of The Astrocyte Reservoir Of HIV-1 In The Central Nervous System
Funder
National Health and Medical Research Council
Funding Amount
$592,661.00
Summary
HIV infects the brain causing dementia in 10-20% patients. Strategies aimed at eradicating HIV infection fail to take into account CNS infection. Understanding the way in which HIV enters, infects and replicates in the brain is pivotal in development of drugs to prevent brain infection and dementia. Our studies have shown that HIV infection of the brain involves mechanisms distinct to those observed for blood and other organs. This study seeks to clarify such mechanisms.
Worldwide there are approximately 40 million people living with HIV-AIDS. An effective HIV vaccine does not exist at present. Therefore, current strategies to control the HIV pandemic include the use of life saving antiretroviral drugs. While the current drugs are successful in controlling infections, new and more effective agents are needed that inhibit HIV replication by distinct mechanisms due to the inevitable development of drug resistant strains of HIV. The HIV reverse transcriptase enzyme ....Worldwide there are approximately 40 million people living with HIV-AIDS. An effective HIV vaccine does not exist at present. Therefore, current strategies to control the HIV pandemic include the use of life saving antiretroviral drugs. While the current drugs are successful in controlling infections, new and more effective agents are needed that inhibit HIV replication by distinct mechanisms due to the inevitable development of drug resistant strains of HIV. The HIV reverse transcriptase enzyme is essential for HIV replication and has been a successful target for nucleoside reverse transcriptase inhibitors (NRTIs) and nonnucleoside reverse transcriptase inhibitors (NNRTIs). NNRTIs act in part by stabilizing the reverse transcriptase enzyme, thus blocking enzyme function. However, no drugs have been developed that can specifically prevent formation of the reverse transcriptase enzyme, which would result in the production of noninfectious viral particles. We propose that formation of the active reverse transcriptase enzyme, from a large polyprotein called Gag-Pol, proceeds through a homodimer intermediate, which represents an ideal target for blocking reverse transcriptase formation in HIV infected cells. This homodimer intermediate is an attractive target with greater potential for disruption with small molecule inhibitors compared to the mature reverse transcriptase enzyme as it is less stable than the reverse transcriptase found in viruses. This study will determine whether formation of the active RT enzyme is dependent on this intermediate. In addition, we will examine how the reverse transcriptase encoded on Gag-Pol regulates activation of the HIV protease, which is also critical for the formation of infectious virus particles. These studies will increase our understanding of how the virus produces infectious particles and will identify new approaches for targeting the HIV reverse transcriptase enzyme.Read moreRead less