Human iPSC-derived neurons reveal NMDAR-independent dysfunction following HIV-associated insults

The central nervous system encounters a number of challenges following HIV infection, leading to increased risk for a collection of neurocognitive symptoms clinically classified as HIV-associated neurocognitive disorders (HAND). Studies attempting to identify causal mechanisms and potential therapeutic interventions have historically relied on primary rodent neurons, but a number of recent reports take advantage of iPSC-derived neurons in order to study these mechanisms in a readily-reproducible, human model. We found that iPSC-derived neurons differentiated via an inducible neurogenin-2 transcription factor were resistant to gross toxicity from a number of HIV-associated insults previously reported to be toxic in rodent models, including HIV-infected myeloid cell supernatants and the integrase inhibitor antiretroviral drug, elvitegravir. Further examination of these cultures revealed robust resistance to NMDA receptor-mediated toxicity. We then performed a comparative analysis of iPSC neurons exposed to integrase inhibitors and activated microglial supernatants to study sub-cytotoxic alterations in micro electrode array (MEA)-measured neuronal activity and gene expression, identifying extracellular matrix interaction/morphogenesis as the most consistently altered pathways across HIV-associated insults. These findings illustrate that HIV-associated insults dysregulate human neuronal activity and organization even in the absence of gross NMDA-mediated neurotoxicity, which has important implications on the effects of these insults in neurodevelopment and on the interpretation of primary vs. iPSC in vitro neuronal studies. Human iPSC-derived cortical neurons (WTC11 i3 neurons) were cultured for 19 days and exposed to either Veh (DMSO), Raltegravir (0.1 or 1 uM), Elivtegravir (1 or 10 uM), or supernatants from untreated and LPS+ATP treated ipSC-derived microglial supernatants (iMG Sups). Following a multi-day MEA recording experiment, total RNA was isolated from these neurons and analyzed via RNA-seq to observe transcriptional alterations associated with exposure to integrase inhibitor antiretroviral drugs and activated myeloid cell supernatants.