The hCNS-HIV/ARV assay system, a platform utilizing human iPSC-neurons/-microglia/-astrocytes to test HIV/AIDS therapeutics for neurotoxicity related to HIV-associated cognitive disroder (HAND)

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Globally, about 40 million people live with HIV/AIDS, and HIV antiretroviral agents (ARVs) are a multi-billion dollar pharmaceutical sector with continued development of agents. Thanks to combination antiretroviral therapy (cART, in which 2 to 4 ARVs are given, simultaneously) HIV+ people have a near-normal life-span. HIV+ pregnant women also receive cART, and their children are given cART prophylactically at birth (in general, cART is given to all HIV+ infants and children). For all HIV+ patients, if cART is stopped, HIV replication restarts; thus, HIV+ people must remain on cART for the rest of their lives. For HIV+ adults, ARVs are present during aging, in which loss of central nervous system (CNS) neurons contributes to loss of cognition/dementia. For HIV+ infants and children, ARVs are present during neurodevelopment. HIV+ individuals frequently develop HIV-Associated Cognitive Disorders (HAND), which includes HIV-associated dementia (HAD,common in AIDS), and less severe forms (asymptomatic neurocognitive impairment and mild neurocognitive disorder (MND). While cART has reduced the incidence of HAD, ANI and MND remain at high levels, even when HIV load is very low. In fact, certain ARVs may contribute to HAND, and alarmingly, HIV+children on cART exhibit developmental delays in intellectual performance. Also, HIV infects/replicates in microglia (MG), an innate immune cell of the CNS, and MG are out of the reach of ARVs that are poor at crossing the blood:brain barrier. More brain-penetrant ARVs were developed, but, unexpectedly, these are linked to greater incidence of HAND. Preclinical research on ARV neurotoxicity has been conducted on primary rodent neurons and glial. Our goal is to develop an assay system (dubbed the hCNS-HIV/ARV platform) for testing ARVs for neurotoxicity and efficacy at inhibiting HIV, neurons, MG and astrocytes (another glial cells), derived from human induced pluripotent stem cells (hiPSC-neurons, hiPSC-MG, and hiPSC-ACs). In phase I, we developed methods for testing ARVs on hiPSC-neurons plated in 384-well dishes, utilizing high-throughput digital microscopy/analysis. We found neurotoxicity (reductions in neurites, synapses, and calcium transients) for elvitegravir (EVG, strongest effect, matching data with rat neurons), dolutegravir (DTG, linked to birth defects), and tenofovir disoproxil fumerate (TDF) and certain combinations of ARVs representing cART had stronger effects than the ARVs, alone. TDF also reduced the viability and elicited epigenetic changes in human neural precursor cells (hNPCs), suggesting that TDF may affect neurogenesis, a process critical for neurodevelopment and cognition. In phase II we will develop standard assay protocols/analysis methods for testing ARVs and HIV infection, itself, on hiPSC-neurons/-MG/-ACs, and on hiPSC-NPCs. The hCNS- HIV/ARV platform will enable development of ARVs that inhibit HIV with minimal neurotoxicity and will be marketed to pharmaceutical companies developing novel therapeutics for HIV/AIDs.