Human immunodeficiency virus type 1 (HIV-1) infection can lead to severe central nervous system (CNS) dysfunctions. A syndrome consisting of cognitive and motor function abnormalities entitled the acquired immunodeficiency syndrome (AIDS) dementia complex (ADC) may occur in a significant portion of individuals infected with HIV-1. The pathogenesis of ADC remains enigmatic and molecular mechanisms leading to neuronal and glial cell damage and death may involve toxic effects from viral proteins and proinflammatory cytokines. Recently, these laboratories have developed an in vitro blood-brain barrier (BBB) system with which to model HIV-1 CNS therapeutics. In the first specific aim of this proposal, they will use this newly developed in vitro BBB system, which contains human CNS microvascular endothelial cells (MVEC), human fetal astrocytes, neuronal elements, and microglia/macrophages, to study molecular therapeutics to inhibit HIV-1 infection in the CNS. Both RNA- and protein-based approaches will be utilized to inhibit HIV-1 expression in isolated CNS-based cell-types and in the in vitro BBB system. In addition, molecular therapeutics will also be modeled in macaque CNS cell-types, utilizing molecular moieties which inhibit simian immunodeficiency virus (SIV). As such, it is hoped that these initial studies will be useful in the design of animal models to explore molecular therapeutics for lentiviral infection of the CNS in vivo. In the second specific aim, pharmacological therapeutics will be utilized in these in vitro model systems to inhibit HIV-1 infection in CNS-based cells. There has been significant progress in treating HIV-1 infection, utilizing combination therapeutics which inhibit the reverse transcriptase (RT) and the protease of HIV-1. Nevertheless, the CNS may be a critical """"""""sanctuary site"""""""" in the treatment of individuals with these combination modalities. As such, experiments will be performed to analyze a variety of combination therapeutics for their viral inhibitory properties and potential for crossing the BBB during therapy. Relevant protease and RT inhibitors will be utilized in these studies. As such, these specific aims hope to yield critical data in the design of therapeutics to alter HIV-1 infection in CNS-based cells, and potentially for ADC in HIV-1-infected-individuals.