GFP-Lentiviral Vectors Targeting for NeuroAIDS

Abstract

Human immunodeficiency virus type 1 (HIV-1) is the causative agent of acquired immunodeficiency syndrome (AIDS). HIV-1 can infect human brain macrophages and microglial cells, causing HIV-associated dementia, or neuroAIDS, an increasingly common disorder of the central nervous system (CNS) that affects 20% of HIV-1-infected individuals. Current treatments for neuroAIDS are hampered by the poor efficiency of many antiretroviral drugs to cross the blood-brain barrier (BBB). Circulating blood monocytes and their derived macrophages are known to migrate across the BBB and enter the CNS under normal physiologic conditions and certain circumstances; some of these cells can subsequently mature into long-lived tissue-resident brain macrophages and microglia. Thus, the natural homing/migratory properties of blood monocyte-derived macrophages (MDM) can be potentially utilized as an effective genetic tool for delivering anti-HIV-1 genes to the CNS in a noninvasive and nonsurgical manner. To test and establish this macrophage-based gene therapy for the CNS, we have constructed and generated high-titered defective lentiviral vectors (DLV) expressing enhanced green fluorescent protein (GFP) as a reporter and optimized protocols for the isolation and long-term cultivation of primary MDM from humans and mice. We have demonstrated that primary cultures of human and mouse MDM can be efficiently modified in vitro using GFP-DLV vectors without apparently adverse effects on cellular biological properties. We have also shown that primary mouse MDM can enter the brain. The efficiency of CNS uptake of these cells can be enhanced through the use of bradykinin or a hypertonic mannitol solution for transient disruption of the BBB. These experimental methods and findings lay the initial groundwork for future in vivo studies on the ability of GFP-DLV-modified blood MDM to introduce anti-HIV-1 and neuroprotective genes into the CNS.