Effects of HIV-1 Tat and drugs of abuse on antiretroviral penetration inside different CNS cell types

Human immunodeficiency (HIV) infection can result in neurocognitive deficits in about one-half of infected individuals. Despite excellent systemic effectiveness, restricted antiretroviral penetration across the blood-brain barrier (BBB) is a major limitation in fighting HIV infection within the central nervous system (CNS). Drug abuse exacerbates cognitive impairment and pathologic CNS changes in HIV-infected individuals. This work investigates the effects of the HIV-1 protein, Tat, and drugs of abuse on factors affecting drug penetration into the brain. Firstly, an in vitro model of the blood-brain barrier was built to study effects of HIV-1 Tat and methamphetamine (Meth) on integrity and function of the BBB, in turn how HIV-1 Tat and meth will affect antiretroviral penetration into the brain. We found that co-exposure HIV-1 Tat and Meth results in inhibition or impairment of P-glycoprotein activity at the BBB. Also, simultaneous inhibition of P-glycoprotein (P-gp) and Multidrug Resistant Protein -1 (MRP-1), by verapamil and MK-571 causes an increase in accumulation of atazanavir inside the primary human brain endothelial cells. Secondly, we developed and validated the method for simultaneous determination of tenofovir, emtricitabine, and dolutegravir in cell extracts of CNS cells. This method was used to study how HIV-1 Tat and/or morphine affects antiretroviral penetration in CNS cells like human brain microvascular endothelial cells, human astrocytes, human microglia, and human pericytes. We found that in untreated cells, accumulation of antiretroviral drugs was higher in hCMEC/D3 cells compared to other CNS cell types. Also, HIV-1 Tat and/or morphine had no significant effect on antiretroviral penetration amongst these cell types. Overall, the rank order of intracellular accumulation observed in treated and untreated cells was dolutegravir \u3e emtricitabine \u3e tenofovir