HIV antiretrovirals have differential effects on viability and function in human iPSC-derived neurons and neural precursor cells

Combination antiretroviral therapy (cART) improves life expectancy and lowers the incidence of central nervous system (CNS) opportunistic infections, lymphomas, and HIV-associated dementia in HIV+ people. However, mild-to-moderate HIV-associated neurocognitive disorders (HAND) persist in about 50% of HIV+ people, even when HIV replication is well controlled. In vitro, animal model, and clinical studies suggest that cART neurotoxicity could be a contributing factor to the progression of HAND. In this study, we developed two in vitro model systems using glutamatergic neurons derived from human induced pluripotent stem cells (hiPSC-Gluts) and fetal neural precursor cells (hNPCs) to assay for antiretroviral (ARV) effects on mature and developing neurons, respectively. We tested four ARVs: the nucleoside/nucleotide reverse transcriptase inhibitors tenofovir disproxil fumarate (TDF) and emtricitabine (FTC) and the integrase inhibitors dolutegravir (DTG) and elvitegravir (EVG). DTG, EVG, and TDF decreased hiPSC-Glut viability and neurite length; all four antiretrovirals decreased hiPSC-Glut synapse counts; and DTG and EVG decreased the frequency and magnitude of hiPSC-Glut calcium transients. The magnitude of these neurotoxic effects increased with longer ARV exposure times and with the exposure of hiPSC-Gluts to two or three ARVs simultaneously. These results suggest that certain ARVs could cause HAND by decreasing the survival and function of CNS neurons. In fetal hNPCs, TDF decreased viability and changed the distribution of epigenetic histone modifications, suggesting that this ARV may alter neurogenesis, which could impair cognition in adults and/or CNS development for those exposed to ARV in utero or early childhood. Our study establishes human preclinical neurotoxicity systems that can screen for potential ARV CNS toxicity and develop safer cART regimens.