Novel Antiviral Strategies Targeting the Human Immunodeficiency Virus Type 1 (HIV-1) Viral Protein R and Its Cellular Partner, the Glucocorticoid Receptor

摘要

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.