Dopamine D1-like receptor stimulation promotes HIV neuroimmune pathogenesis in iPSC-derived human cortical assembloids

About This Grant

Neurologic complications remain prevalent in nearly 50% of people with HIV (PWH) and persist despite viral suppression with antiretroviral therapy (ART). Though the exact processes mediating HIV neuropathogenesis are not well understood, co-morbidities such as substance use disorders (SUD), which are higher in PWH compared to the general population, exacerbate neuropathogenesis of HIV and worsen outcomes. Multiple substances of misuse are reported to increase HIV replication, induce inflammatory signaling, and amplify neurodegenerative phenotypes. Thus, there is a significant need to understand the intersection between SUD and NeuroHIV to improve longitudinal care and inform the public. The overlapping effects of distinct substances of misuse on HIV pathogenesis in the CNS suggest that a common pathway may be involved through presently undefined mechanisms. All addictive substances increase extracellular dopamine in the central nervous system (CNS), which signals neurons and other nearby glial cells expressing dopamine receptors. Our lab has shown that myeloid cells such as macrophages and microglia, which are major HIV reservoirs in the brain, express dopamine receptors more D1-like receptors (D1 and D5) than D2-like receptors (D2, D3, D4). Treatment of macrophages and microglia with micromolar concentrations of dopamine increased pro-inflammatory signaling, increased viral entry, and potentiated viral secretion in vitro. We recently found that a higher D1-like to D2-like ratio is associated with a more pro-inflammatory response in microglia. Further, we showed that dopamine increases activation of nuclear factor-kappa B (NF-κB) in macrophages, and that inhibition of NF-κB can block the pro-inflammatory effects of dopamine. Together, these data suggest that dopamine-enriched brain regions, such as the cortex and striatum, may be especially vulnerable to HIV and neuroinflammation in PWH and co-morbid addiction through the action of dopamine on microglia. Therefore, the central hypothesis of this proposal is that dopamine D1-like receptor activation promotes HIV infection and NF-κB-mediated inflammation in microglia to worsen neurodegeneration. This hypothesis will be tested using human induced pluripotent stem cell (iPSC)-derived brain human cortical assembloids and several orthogonal assays to explore the dopamine-mediated pathways that modulate HIV neuroimmune pathogenesis. We will use pharmacologic activation of dopamine receptors in cortical assembloids to assess viral kinetics (Aim 1), neuroinflammation (Aim 2), and neuronal degeneration of synapses and dendrites (Aim 3). Together, these studies will significantly advance our understanding of dopamine as an immunomodulatory signaling molecule in the context of substance use and HIV, as well as expand the approaches to studying neuroimmune pharmacology using human micro-physiological systems.