Project Summary Abstract Our proposal will address the impact of cocaine on exosome-mediate HIV-1 entry of the central nervous system (CNS) resident cells. Multiple studies have shown that HIV-1 patients may develop virus reservoirs that impede eradication; these reservoirs include cells found in the CNS. Many substances of abuse have been shown to increase HIV-1 Infection. HIV-infected, drug- abusing individuals may experience more severe or faster-progressing HIV-1 related neurological impairment. Some of the main mechanisms have shown that with drugs of abuse there is increased oxidative stress and increased permeability seen in the blood brain barrier (BBB). Exosomes can act as potential facilitators of HIV-1 infection in the CNS. CD4+/CCR5+ cells are the predominant target cells of HIV-1 infection. However, since evidence exists for HIV-1 infection of CD4-lacking astrocytes, these cells could have a potential role as HIV-1 reservoirs. Thus, alternative HIV-1 entry and infection mechanisms likely exist for CNS resident cells, but to date, limited information on this topic exist. Exosomes crossing the BBB, or being released from cells within the CNS (including HIV-1 infected cells of the monocytic lineage) may be an important link to alternative HIV-1 infection pathways in the CNS. Our approach will allow evaluation of exosome-mediated HIV-1 entry into CNS cells as well as immune cells within this site (in vitro). Specifically, we will test the hypothesis that exosome- mediated mechanisms significantly facilitate HIV-1 entry in the CNS, and that cocaine can augment this process of infection. These processes will be evaluated and provide a basis for new and effective therapeutics.