Although the precise mechanisms whereby HIV-1 infection induces neurodegeneration have yet to be determined, a large body of evidence has incriminated glial cells and the production of proinflammatory mediators. For this reason, ideal therapeutic agents for the treatment of AIDS dementia would possess anti-inflammatory as well as anti-viral properties. Benzodiazepines, such as diazepam (Valium), are extensively prescribed drugs for anxiety disorders which readily cross the blood-brain barrier and have demonstrated immunomodulatory properties as well as antiviral activity in HIV-1-infected cell lines. In this application, the central hypothesis to be tested is that anxiolytic drugs attenuate HIV-1 neuropathogenesis through both inhibition of viral expression and suppression of brain cell-produced immune mediators. To characterize their inhibitory effects on HIV-1 expression in brain cells, human glial and mixed glial/neuronal cell cultures, as well as chronically infected promonocytes (U1 cells), will be infected with HIV-1 and maintained in the presence or absence of anxiolytic drugs. Expression of HIV-1 p24 Ag in culture supernatants will be quantified by ELISA. To test the hypothesis that the antiviral properties of anxiolytic drugs are mediated through an inhibition of cellular transcription factor activation, nuclear extracts from HIV-1-infected human glial cells as well as U1 cells, incubated in the presence or absence of anxiolytic drugs, will be probed for nuclear factor kappa B (NF-kB) activation. To link the effects of anxiolytic drug-induced inhibition of NK-kB with direct inhibition of HIV-1, transient transfection assays using HIV-1 promoter-reporter gene constructs, which contain either normal or mutated NF-kB consensus sequences, will be performed. To test the hypothesis that anxiolytic drugs attenuate HIV-1 neuropathogenesis by inhibiting the production of immune mediators, glial and mixed glial/neuronal cell cultures will be infected with HIV-1 and examined for the production of proinflammatory cytokines and beta-chemokines. The results of the proposed studies aims to contribute to a further understanding of HIV-1 neuropathogenesis and will hopefully have therapeutic implications regarding suppressing viral replication and neurodegeneration in HIV-1-infected patients.
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