Single Cell Transcriptomics of the Opioid Use Disorder and HIV Syndemic in the Human Brain

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PROJECT SUMMARY Persistent immune activation is the defining feature of HIV-1 infection in vivo and a driver of progression to end-stage AIDS. Systemic immune activation in people living with HIV has been hypothesized to account for higher incidence of chronic inflammatory diseases, including HIV-associated neurocognitive disorders (HAND). While significant neurological complications associated with HIV-1 infection occur years after seroconversion and is commonly coincident with progressive immunosuppression and high viral loads, establishment of a virus reservoir in the CNS occurs with primary infection. Furthermore, acute infection in the CNS is thought to initiate a cascade of pro-inflammatory events that result in inflammation- induced neuronal injury and associated neurocognitive disorders that are evident even in the present combination antiretroviral therapy (cART) era. Approximately 12 million people inject drugs globally, 13% of these are people living with HIV. Opioid misuse is a route of HIV acquisition and a barrier to effective antiretroviral therapy (ART). However, it is unclear whether opioid misuse changes the course of HIV pathogenesis, especially on HIV-associated neurocognitive disorders. Our central hypothesis is that opioid misuse exacerbates HIV pathogenesis in the CNS by dysregulating the glial population in the brain. Our overall objective is to exploit cell type specific transcriptomic information at the single nuclei level from patient brain samples to characterize the effects of opioid use disorder on CNS neuronal and glial cells, HIV infection and HANDs. We will characterize single nuclei gene expression and identify dysregulated gene regulatory networks in each of the neuronal and glial populations associated with opioid misuse in HIV infected individuals and/or with HANDs. We will also perform computational analysis to identify neuronal and glial cell regulatory networks altered by opioid misuse. In the validation component, we will select the top 20 targets from single cell transcriptomics profiles, first validating with immunohistochemistry with fixed brain tissue, then selecting a few top targets and using 2D and 3D cultures of iPS derived neurons, microglia and astrocytes to characterize functionality with CRISPR knockout. Successful completion of these aims will have significant research and clinical impact by 1) elucidating how opioid misuse alters HIV/HAND pathogenesis in the CNS, and 2) discovering candidate molecules to regulate HIV infection or persistence in the CNS in the context of opioid misuse.