June 2001: Grants Target HIV/AIDS Prevention and Treatment
In June 2001, amfAR announced basic research grant awards totaling over $3 million for new projects aimed at developing an AIDS vaccine, microbicides, new anti-HIV drugs, and methods of restoring immune function in people with HIV/AIDS. Two research awards amounting to nearly $500,000 were made as part of a new initiative that will involve the screening of libraries of chemical compounds for substances that could block the function of certain key HIV genes. The first of its kind, this effort will allow two researchers to screen so-called “combinatorial libraries” of tens of thousands of chemicals for those capable of attacking new targets in the AIDS virus. Two potential targets, the viral proteins known as Vif and ribonuclease H (RNase H), play essential roles in the replication of HIV, but have not as yet been studied as potential targets for new drugs.
The Foundation awarded 17 grants totaling more than $1.2 million for innovative new studies to develop AIDS vaccines and methods of restoring immune function in HIV-infected individuals, as well as continued efforts to identify novel viral and cellular targets for the development of new anti-HIV drugs. amfAR released $3.21 million in grants for vaccine and immune restoration studies in June 2000, and distributed an initial $1.7 million in grants for projects to identify new anti-HIV drug targets in February 2001.
The latest grant cycle also included $445,794 in grants to five researchers seeking to develop microbicides, substances that could be applied topically to neutralize the AIDS virus and block other sexually transmitted microbes that facilitate HIV transmission. The Foundation awarded an initial $875,000 in grants for targeted microbicide research in December 1999.
amfAR also announced $890,848 in funding for its Fellowship Program, which enables young investigators to conduct original AIDS research under the guidance of experienced senior scientists.
Both amfAR grantees and fellows are selected through a rigorous process of peer review by members of amfAR’s Scientific Advisory Committee, a team of highly qualified professionals who volunteer their time and expertise to evaluate proposals on the basis of scientific merit, promise, and relevance.
A complete listing of grantees, grant amounts, and brief descriptions of the research proposals follows:
COMBINATORIAL LIBRARY GRANTS
Dana Gabuzda, M.D., Dana-Farber Cancer Institute
HIV Vif as a Target for Small Molecule Inhibitors: Previous studies have shown that the viral gene Vif interferes with some component of normal cells that would otherwise prevent HIV from growing. Dr. Gabuzda will use previously-developed assays to screen large combinatorial libraries of chemicals with small molecules in order to identify substances that bind to and inhibit Vif and so would also suppress HIV replication. Such screening is intended to pave the way for the development of new anti-HIV therapies.
Michael A. Parniak, Ph.D., University of Pittsburgh
RNase H as a Target for Anti-HIV Agents: The viral protein ribonuclease H (RNase H) is essential for HIV replication, but current assays to measure RNase H activity are extremely time-consuming and cumbersome and unsuitable for high throughput screening of large numbers of chemicals. Dr. Parniak will use a new fluorescence-based assay for RNase H to screen combinatorial libraries in order to identify compounds that can inhibit RNase H activity and thus also HIV replication. This screening is also intended to lead to the development of new anti-HIV therapies.
GENERAL BASIC RESEARCH GRANTS
Etty N. Benveniste, Ph.D., University of Alabama at Birmingham
CD40/CD154 Mediated Reactivation of Latent HIV-1 Infection: Immune cells called macrophages are one reservoir of infectious HIV. This project will investigate the role of the CD40 molecule on the surface of macrophages in reactivating latent virus and attempt to determine the specific cellular factors and biochemical signals involved in CD40-mediated reactivation of latent HIV-1 infection in macrophages. It is hoped that controlled reactivation of latent HIV-1 in these cells might render the virus susceptible to both antiretrovirals drugs and the immune system response to HIV, a virus that is impervious to both in its patent form.
Andrew G. Campbell, Ph.D., Brown University
Retroviral RNase H Mutants: Selection and Drug Screening: This project seeks to (1) construct and test all possible mutations in retroviral RNase H and screen these mutants in order to identify genetic changes that allow the virus to remain active; (2) test these mutant viral RNase H proteins to determine their susceptibility or resistance to new lead compounds that show promise as anti-HIV therapeutics; and (3) develop a laboratory-based system that can be used to rapidly and safely screen for new lead compounds effective in blocking HIV replication and disease progression.
Thomas B. Campbell, M.D., University of Colorado Health Sciences Center
Latent HIV-1 Induced by Stem Cell Mobilization: In preliminary studies, treatment of HIV-infected individuals with a drug that increased the number of stem cells in the blood (stem cell mobilization) also caused a temporary increase in HIV production, suggesting that stem cells may be reservoirs of HIV infection. Moreover, the HIV produced during stem cell mobilization differed from the virus present in the blood prior to treatment. In an effort to better understand how HIV is able to remain latent in infected individuals, Dr. Campbell will explore whether stem cell mobilization activates latent HIV, the relationship between the virus produced during stem cell mobilization and that existing beforehand, and the exact source of the HIV produced during stem cell mobilization.
Paul Clapham, Ph.D., University of Massachusetts Medical School
Astrocyte Receptors and HIV-1 Brain Envelopes: Some 20 to 30 percent of AIDS patients suffer from neurological disorders, including dementia, that result from HIV infection of brain tissue. In addition to infecting immune cells called microglia, there is growing evidence that HIV may directly infect brain cells called astrocytes. Astrocytes do not have the same surface receptors that HIV uses to infect immune cells, and this project seeks to determine whether HIV in the brain has adapted to use astrocyte receptors. If so, such receptors would be potential targets for new anti-HIV drugs.
Kelly Stefano Cole, Ph.D., University of Pittsburgh
Immune Maturation and AIDS Vaccine Protection: Dr. Cole’s laboratory has developed two new tests that have helped clarify the specific regions of simian immunodeficiency virus (SIV) envelope proteins responsible for eliciting antibody responses. They are currently being tested as immune correlates of SIV vaccine efficacy. The research proposed will expand these studies to evaluate antibody responses to specific segments of HIV’s envelope. By making complementary HIV envelope antigens and using these new antigens to characterize antibody responses elicited by experimental SHIV infection and vaccination, the project will attempt to identify reliable correlates of protection that can be used to evaluate candidate AIDS vaccines.
Cynthia Derdeyn, Ph.D., University of Alabama at Birmingham
Sensitivity of Primary HIV-1 to Fusion Inhibitors: A new class of anti-HIV drugs called fusion inhibitors can inhibit viral replication of HIV-1 in cultured cells and interfere with the changes in HIV’s envelope proteins that mediate entry into target cells. Previous studies have shown that laboratory-derived viruses that use the CCR5 co-receptor are more difficult to inhibit than similar viruses that use the alternate co-receptor CXCR4, and that small differences in HIV’s envelope proteins can affect sensitivity to specific inhibitors. The current project will investigate the role of the HIV envelope proteins and target cell receptors in determining sensitivity to anti-HIV fusion inhibitors.
Ganjam V. Kalpana, Ph.D., Albert Einstein College of Medicine
Role of Nuclear Export of INI1 in HIV-1 Replication: HIV’s integrase protein is responsible for insertion of the viral DNA into the host cell genome. Recent studies have confirmed a direct, physical association between integrase and a human protein integrase interactor 1 (INI1), that normally resides in the cell nucleus but migrates into the cytoplasm after HIV infection occurs and then returns to the nucleus. It is hypothesized that the HIV-1 induced dynamic shuttling of INI1 between the nucleus and cytoplasm is a necessary event for successful viral replication. This study will attempt to identify the specific factors that mediate the shuttling of INI1 and determine whether and how this shuttling facilitates viral replication.
Lawrence Kleiman, Ph.D., Sir Mortimer B. Davis–Jewish General Hospital
Incorporation of LYSYL t-RNA Synthetase into HIV-1: In order for HIV to grow, it must co-opt several normal cell proteins. One such key protein is transfer RNA (tRNA). tRNA binds to the genetic material or viral RNA of HIV, thereby permitting the virus’ reverse transcriptase to function. Dr. Kleiman will explore the role of a cell protein known as lysyl tRNA in this process, with the goal of establishing a potential new target for anti-HIV drugs.
David M. Lukac, Ph.D., University of Medicine and Dentistry of New Jersey, New Jersey Medical School
Synergy of KSHV ORF57 with the Viral Lytic Switch Protein: Kaposi’s Sarcoma-Associated Herpesvirus, or KSHV, infects the B cells of the immune system, where it remains latent. Once reactivated, KSHV is associated with increased risk of primary effusion lymphoma and Kaposi’s Sarcoma. This study seeks to identify the molecular mechanisms by which a viral protein called ORF50 reactivates latent HIV infection, and a second protein called ORF57 enhances ORF50’s function, in the hopes of discovering methods of inhibiting one or both mechanisms.
David M. Margolis, M.D., University of Texas Southwestern Medical Center at Dallas
Towards Therapeutic Modulation of HIV Expression: Human cellular components can inhibit HIV’s genetic expression or growth. These host factors act on HIV’s “on-off” switches, one of which is referred to as LAR, to suppress HIV gene expression. Dr. Marigolis will study a group of host cell repression factors that have been found to inhibit the LAR, in the hopes of developing therapies that could specifically regulate HIV gene expression.
Olympia Meucci, M.D., Ph.D., MCP–Hahnemann University
Role of Cell Cycle Proteins in HIV-1 Neurodegeneration: While HIV does not infect neurons directly, death of neurons occurs in the brains of both adult and pediatric AIDS patients, and neuronal dysfunction and loss has been found to be a direct consequence of HIV infection of the brain. All the major cell types in the brain, including neurons, possess proteins on their surface called chemokine receptors, which seem to be implicated in neuronal survival as well as in HIV pathogenesis. This project will study whether chemokine receptors affect the activity of cell cycle proteins that regulate cell division in order to determine whether the interaction of HIV’s gp120 envelope protein with chemokine receptors somehow induces the cell cycle machinery to signal neuronal death.
Richard A. Oberhelman, M.D., Tulane School of Public Health and Tropical Medicine
New Orleans, LA
Diagnosis of AIDS-Related Pediatric TB (Peru): Dr. Oberhelman’s project will evaluate novel approaches to diagnosing tuberculosis (TB) in children who don’t have the usual chest x-ray signs of the disease, testing (1) less invasive methods than those now commonly used, i.e., nasal washings instead of stomach aspiration; and (2) simple, rapid, and inexpensive methods of culturing the TB bacterium that could significantly simplify the diagnosis of a disease that is the major infectious cause of death among people with AIDS in the developing world.
Griffith D. Parks, Ph.D., Wake Forrest University School of Medicine
Simian Virus 5 as a Novel HIV Vaccine Vector: Recombinant viruses represent a powerful tool for the delivery of vaccines, and this project will test the effectiveness of genetically engineered RNA virus simian virus 5 (SV5) as a vector for delivering a vaccine that can elicit a potent anti-HIV cellular immune response.
Nahum Sonenberg, Ph.D., McGill University
Translational Mechanisms of HIV-1: The translation of the cellular messenger RNAs that initiate viral protein synthesis is mediated by an unusual mechanism involving an internal ribosome entry site (IRES). This project seeks to identify cellular proteins and other factors capable of modulating IRES activity and to characterize the RNA-protein interactions involved in its regulation, with the goal of facilitating the design of drugs to inhibit IRES activity.
Lishan Su, Ph.D., University of North Carolina, Chapel Hill
Chapel Hill, NC
Nonlytic CD8 T Cell Factors Associated with HIV LTNP: AIDS progression has an inverse correlation to the CD8+ cell antiviral factor (CAF) activity, suggesting that this factor or group of factors can control HIV replication. There is also evidence that CAF activity may help protect against primary HIV infection. Thus, an effective AIDS vaccine should enhance CAF activity. Dr. Su will attempt to use a new assay to isolate antiviral factors produced from the T cells of HIV-infected patients who show no disease progression, and to characterize the mechanisms of CAF and other potential anti-HIV suppressive factors.
Richard E. Sutton, M.D., Ph.D., Baylor College of Medicine
Development of a Mouse Model for HIV/AIDS: A mouse animal model would greatly simplify the testing of potential AIDS vaccines, but researchers have been unable to grow HIV in mouse cells, even with the addition of three human proteins that mouse cells lack. This project will utilize two different genetic approaches in an effort to isolate and characterize any novel human host factors that will allow HIV to replicate in mouse cells.
Jerome A. Zack, Ph.D., University of California, Los Angeles
Los Angeles, CA
Induction of Expression of Latent HIV by Prostratin: If reservoirs of latent virus could be eliminated, patients might eventually be able to discontinue antiretroviral therapy. Dr. Zack’s laboratory has developed an animal model that can be used to test the ability of drugs to activate the expression of latent HIV, which might give the immune system an opportunity to kill HIV-infected cells and prevent the spread of infection to additional cells. This project will test the ability of a new agent called prostratin to activate latent HIV and study its effect on immune system organs that participate in the development of T cells.
Andrew V. Albright, Ph.D., University of Pennsylvania
A Novel HIV Latency System: This study will explore how HIV infects and remains latent in the macrophages of the central nervous system (known as microglia); which cellular and viral components induce either latent infection or the reactivation of HIV; which class of antiretrovirals can block the release of infectious HIV from microglia; and whether latent HIV infection in the central nervous system can destroy brain tissue.
Michelle A. Barron, M.D., University of Colorado Health Sciences Center
Recombinant Yeast Vaccines for HIV-1: Dr. Barron seeks to use whole genetically modified Brewer’s yeast as a vector for a therapeutic AIDS vaccine that can hopefully elicit strong immune responses from the dendritic cells that alert CD4+ helper T cells and CD8+ “killer” T cells to the presence of HIV. Ultimately, it is hoped that combining antiretroviral therapy with a therapeutic vaccine will result in immune responses specifically directed against HIV and allow for more complete control of viral replication in the event that antiviral therapy fails or can no longer be tolerated.
Daniel Boden, M.D., Aaron Diamond AIDS Research Center
New York, NY
Integrase-Deleted HIV-1 Mutants: A Potential Vaccine: This project seeks to construct a virus that mimics the natural behavior of HIV but is unable to repeatedly multiply in human cells. Specifically, deleting a large part of the integrase gene that is essential to HIV’s replication may produce a virus that can continuously express low levels of natural viral proteins, thus inducing the persistent production of antibodies and immune cells directed against HIV without the risk of infection associated with live attenuated viruses.
Maria Pia de Pasquale, Ph.D., Massachusetts General Hospital
Drug Transporters and HIV-1 Pathogenesis During Therapy: The failure of antiretroviral therapy is not always due to the development of drug-resistant HIV strains or to low levels of anti-HIV drugs in the blood. This project will explore whether antiretrovirals, or HIV infection itself, induce the production of specific cellular factors known as cellular “drug transporters” that can move protease and reverse transcriptase inhibitors out of HIV-infected cells.
Nedim Ince, M.D., Center for Blood Research
Inhibitory Receptors and CTL Function in HIV Disease: Dr. Ince seeks to identify the role of inhibitory receptors on CD8 cytotoxic T cells that interfere with the ability of these T cells to kill HIV-infected cells and secrete substances called cytokines that regulate immune function. The study will focus particular attention on how an inhibitory receptor called immunoglobulin-like transcript-2 (ILT2) may interfere with CD8 cell activation and whether stimulation of a cytokine called interleukin-2 (IL-2) reduces ILT2 expression as it restores CD8 T cell function.
Georgette Kanmogne, Ph.D., University of Oklahoma Health Sciences Center
Oklahoma City, OK
Cellular Mechanisms in AIDS Dementia: Approximately one-quarter of AIDS patients develop severe mental impairments and cognitive deficits called AIDS dementia. This study will test the hypothesis that HIV infection of immune cells in the brain called microglia ultimately causes brain nerve cell death through a series of biochemical events, including stimulation of specific cell surface proteins, activation of internal cellular signal pathways, and the release of HIV molecules from infected microglia.
James J. Kohler, Ph.D., University of Florida
JAK/STAT Activation Via HIV gp120 Binding to CD4: Preliminary studies have shown that so-called STAT proteins are activated following the binding of HIV’s gp120 envelope protein with the CD4 cellular receptor. Activation of specific STAT proteins signals production of cytokines that can either boost or suppress an immune response. Dr. Kohler seeks to determine which specific STAT proteins are activated either directly or indirectly by HIV, and how the signaling pathway involving STAT molecules impacts immune function.
Salman Muzammil, Ph.D., Johns Hopkins University
Amino Acid Polymorphisms and HIV-1 Protease Inhibition: This project seeks to understand the mechanisms by which specific mutations or amino acid polymorphisms in the protease molecule of HIV-1 elicit resistance to protease inhibitors by preventing those drugs from binding effectively to the viral protease; to identify the differences between first and second generation inhibitors and determine whether second generation inhibitors are any less susceptible to mutations than first generation inhibitors, and to develop guidelines for the design of new, more powerful inhibitors that will be less susceptible to drug resistance.
Andrew C.S. Saphire, Ph.D., Scripps Research Institute
La Jolla, CA
Role of Cyclophilin A in HIV-1 Replication: The human protein cyclophilin A acts as a key mediator in the initial attachment of HIV-1 to human cells and represents an attractive new target for the development of antiviral drugs. Antibodies against cyclophilin A are known to block HIV infection, and because cyclophilin is a human protein, it is much less likely to mutate and develop resistance to existing antiretrovirals. Dr. Saphire will attempt to systematically analyze how HIV-1 uses cyclophilin A to attach to and infect human cells with the goal of uncovering novel targets for new anti-HIV therapies.
Gadi Borkow, Ph.D., Ruth Ben-Ari Institute of Clinical Immunology and AIDS Center,
Kaplan Medical Center
UC781, Potent Microbicide in a Human Cervical Model: Previous studies have demonstrated the effectiveness of a non-toxic, highly specific HIV-1 inhibitor called UC781 in destroying the infectiousness of a variety of HIV-1 wild type and resistant viruses. Dr. Borkow seeks to advance this microbicide candidate to the final stage of eligibility for clinical trials by using a novel human cervical culture model to test the capacity of UC781 as part of a gel ointment in blocking cell-free and cell-associated HIV-1 infection of the cervix.
Salvatore T. Butera, D.V.M., Ph.D., Centers for Disease Control and Prevention
Soluble DC-SIGN to Prevent Mucosal HIV Transmission: Following sexual transmission, HIV’s outer envelope latches on to the dendritic cells in the mucosal tissues of the vagina and rectum via a receptor on the dendritic cell surface called DC-SIGN. The dendritic cells then carry HIV to the lymph nodes, where the virus launches its attack on the immune system. This study will attempt to develop a gel or suppository containing a soluble form of DC-SIGN that would effectively coat the outer surface of all incoming HIV viruses. The goal is to prevent HIV attachment to dendritic cells and subsequent transport to the lymph nodes, and possibly contain HIV infection at the site of initial infection where it can be effectively attacked by the immune system.
Akiko Iwasaki, Ph.D., Yale University School of Medicine
New Haven, CT
Rectal and Vaginal Dendritic Cells in SIV Infection: Using a simian immunodeficiency virus (SIV) in rhesus monkeys, this project will study infection of the rectal and vaginal mucosa in order to better understand both the role of dendritic cells in facilitating viral entry and inducing immune response at these mucosal sites, and to explore how the menstrual cycle may affect viral pathogenesis during vaginal exposure.
David F. Katz, Ph.D., Duke University
Biophysical Analysis of Topical Microbicides: This study will obtain direct measurements of the spread and retention (or deployment) of vaginal microbicide formulations in women and interpret these results using fundamental analysis of the biophysics of such deployment. Currently, vaginal microbicides are being developed with very little information on how to select the best formulation, e.g., gel, cream, foam, etc. Dr. Katz has devised a mechanical means of assessing the dynamics of fluid flow in the human vagina before and during sexual intercourse, which will help predict which microbicide products might be the most effective and long-lasting.
Quentin Sattentau, Ph.D., Imperial College of Science, Technology and Medicine
Mechanisms of Polyanion Inhibition of HIV Infection: Negatively charged, sugar-based molecules called polyanions that seem to react with HIV’s surface gp120 protein have been incorporated in a number of microbicide candidates. This study will use biophysical analysis in order to identify the precise regions of gp120 involved in binding polyanions and which polyanions are most potent in inhibiting HIV infectivity in culture, and potentially screen novel candidate inhibitors that have greater selectivity and potency.