Leveraging Directly Reprogrammed Human Neurons to Investigate the Molecular Impact of Age and Distinct Antiretroviral Therapies in Individuals Living with HIV-1

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PROJECT SUMMARY/ABSTRACT Despite advances in clinical care, people living with HIV-1 (PLWH) on long-term antiretroviral therapy (ART) still present with cognitive and behavioral deficits and the prevalence of HIV-1 associated neurocognitive disorders (HANDs) is 30%-50%. The mechanisms underlying HIV-induced central nervous system (CNS) dysfunction in these patients are complex, multifactorial and difficult to study using current methods. In this proposal, we will investigate modifiable mechanistic pathways of neuronal aging in HIV-1 using physiologically relevant, participant-derived cell models. In recent years, the ability to generate directly induced neurons (iNs) from patient-derived fibroblasts has been demonstrated. Unlike the immature neuronal populations generated from induced pluripotent stem cells (iPSCs), iNs retain neuron-specific, aging-associated gene-expression characteristics of the donor. As a result, these iNs represent a major technological advance. Our preliminary data demonstrates our ability to generate iNs from the skin biopsies of PLWH. To our knowledge, this makes us the first group to apply this technology to study of neuronal health in HIV-1. We now propose to use these tools to determine if differences in gene expression reflective of accelerated age- and/or additional HIV disease- associated transcriptional signatures are evident through the transcriptional phenotyping of iNs derived from age-matched young and older HIV-negative and HIV-positive cohorts. Functional analyses of the iNs will test hypothesized pathomechanisms of neuronal aging. A growing body of scientific evidence also suggests that antiretroviral drugs (ARVs) widely used in HIV-1 therapy and known to cross the blood-brain barrier to varying degrees may have class- and/or drug-specific deleterious effects on neuronal health. We therefore, in exploratory secondary analyses, hypothesize that there are potentially modifiable, mechanistic pathways of neuronal injury in HIV-1 that are also ARV class dependent. We will investigate our hypotheses in two specific aims. In AIM 1, we will generate patient-derived iNs from clinically well-characterized participants. We will generate iNs as per Mertens et al. (Cell Stem Cell, 2015) from the skin biopsies of 6 clinically well-defined cohorts stratified by age, HIV-1 status and use of protease-inhibitor (PI)- versus Integrase strand transfer inhibitor (INSTI)-based ART. In AIM 2, we will determine neuronal-associated gene-expression pathways modulated by age, HIV-1 status and cART usage through transcriptional profiling of iNs from well- defined clinical cohorts. Differential gene expression analysis will be performed across cohorts in attempts to determine, age (old vs. young), and in secondary exploratory analyses, HIV-1 (positive vs. negative) and ARV (PI vs. INSTI) effects on gene transcription. We will then determine if age-dependent nucleocytoplasmic compartmentalization (NCC) impairments characterize iNs from older, HIV-1 positive cohorts. Our novel application of this iNs technology to the translational study of PLWH allows us the opportunity to fill a gap in our understanding of neuronal aging in HIV-1 and identify therapeutic targets for improved cognition.