Most highly active anti-retroviral treatment (HAART) regimens eventually fail to provide complete and long-term suppression of virus replication due to the inability to fully clear virus from cellular reservoirs. The HIV-1 viral protein R, Vpr, increases virus replication in T cells and is necessary for the optimal infection of primary monocytes/macrophages and other non-dividing cells. In this essay, it is demonstrated that Vpr interacts with the cellular Glucocorticoid Receptor (GR) and transactivates the HIV-1 LTR through GRE and that this event can be blocked by the GR antagonist, mifepristone. Based on these observations, it is shown that targeting Vpr-mediated virus transcription with the glucocorticoid antagonist, mifepristone, can demonstrate a potent anti-retroviral therapy.
Results demonstrated that Vpr-induced transactivation of both autologous and heterologous promoters was inhibited by mifepristone in a dose-dependent manner by >90% at a 1 µM concentration. Infectivity assays using T-tropic, dual-tropic, and macrophage-tropic viruses demonstrated antiviral effects on a dose-dependent regimen of mifepristone. The effects of mifepristone were also tested in HIV-1 latent cells that could be activated with extracellular viral protein and results exhibited a greater than 90% inhibition of re-activation in the presence of this antagonist. Cytotoxic effects of mifepristone demonstrated a CT50 from 10 to 100 µM in normal human primary cells, HeLa, HEK293, and CV-1 cells.
Statement of Public Health Relevance: By utilizing the interaction between Vpr and the glucocortoicoid receptor, glucocorticoid antagonists such as mifepristone hold promise for anti-retroviral therapy by both preventing viral transactivation in currently-infected cell populations as well as preventing the reactivation of latent virus.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-07292005-211913 |
| Date | 29 September 2005 |
| Creators | Schafer, Elizabeth Ann |
| Contributors | Dr. Meryl Karol, Dr. Phalguni Gupta, Dr. Velpandi Ayyavoo |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-07292005-211913/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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