The effects of cART and HIV-1 infection on neural circuitry - ABSTRACT A significant proportion of individuals receiving antiretroviral therapy (ART) for HIV-1 infection develop cognitive deficits. This may be due solely to the HIV-1 infection; however, this may also indicate that prolonged ART itself may contribute to the impairments, particularly in the context of HIV-1 infection. The latter possibility is of particular concern given that a growing number of uninfected individuals use antiretrovirals (ARVs) as pre- exposure prophylaxis (PrEP). The brain circuitry that may be affected by prolonged treatment with ARVs or by ARVs in the context of HIV-1 infection is unknown. We propose to apply our recently developed array of new tools for constructing, comparing, and analyzing 3D whole-brain maps of neuronal activation in the mouse brain to reveal the critical neural circuitry affected by ARVs, HIV-1 infection, and their combination. Our hypothesis is that 3D patterns of neuronal activation in animals exposed to ARVs, HIV-1, and ARV/HIV-1 and involved in challenging behavioral tasks can both reveal the crucial circuitry defining these effects and serve as unique signatures of the treatments' effects. In specific aim 1, we will determine the critical shared components of neural circuitry affected by prolonged exposure to select ARVs. We will generate mesoscopic global maps of neuronal activation in mice presented with relevant cognitive challenges after exposure to ARVs. We will then subject the mapping datasets to our stepwise selection pipeline to identify the critical brain regions and neural circuits altered by the treatments. In specific aim 2, we will determine the components of neural circuitry in NOD-hIL-34 mice, a humanized animal model of HIV-1 infection, that are affected by exposure to select ARVs in the context of infection. Finally, in specific aim 3, we will validate and extend the conclusions of our in silico investigations: we will monitor neuronal activity in the candidate regions in vivo on the single-cell and population levels; apply monosynaptic tracing to determine whether ARV treatment induces long-term changes in neuronal connections; and use chemogenetics to manipulate neuronal activity in the key components of the inferred circuitry. Our experiments will create a circuitry map space for the action of ARVs in the context of HIV-1 infection, upon which other circuitry maps that describe various behavioral states and responses to treatments can be projected and compared. Our results will help to characterize cognitive impairments in HIV-1 infected individuals receiving ART and in those using ARVs as PrEP, and will inform future therapeutic efforts to treat HIV-associated neurocognitive impairment.
