SALSI: Modeling addiction-related interneuron dysfunction using brain organoids

The `opioid epidemic' is one of the most significant health issues facing this country today with rates of opioid-associated deaths up 200% since 2000. This epidemic is also taking its toll on pregnant women and their babies, with an annual average of ~21,000 pregnant women ages 15 to 44 who have misused opioids this past month.  Infants who have been exposed to opioid drugs  exhibit an increased risk of neurological and behavioral consequences. In spite of significant neurological deficits, two key questions remain: (1) how does maternal opioid misuse affect the developing cerebral cortex at the cellular and molecular level and (2) is there a critical window in infant cerebral cortex development where maternal opioid misuse is especially problematic? Answering these questions may limit the pathophysiologic consequences of maternal opioid misuse and lead to new therapeutic strategies to treat infants exposed to maternal opioids. The development of the human cerebral cortex requires the integration of circuits composed of glutamatergic neurons generated in the embryonic cortex and GABAergic interneurons produced in subpallium. These key developmental processes occuring in mid-to-late gestation are inaccessible in humans. Thus, human induced pluripotent stem cells (iPSCs) differentiated to form cortical interneurons in 3D culture offer a unique opportunity to develop patient-specific models of fetal brain development. Evidence from mouse models suggest that opioid exposure disrupt expression of genes critical for the migration of interneurons, a diverse set of local circuit cells that release the inhibitory neurotransmitter GABA. This proposal will extend work from mouse models to gain insight into mechanisms of opioid exposure during human brain development.  Theoverarching hypothesis of this project is that opioid exposure cause specific interneuron migration and cortical

laminar positioning defects leading to neurologic dysfunction. By capitalizing on their unique expertise in stem cell biology and neurobiology, the Hsieh and Lodge laboratories will work to: (1) differentiate a line of human iPSCs into 3D cortical and subpallium spheroids containing excitatory and inhibitory interneurons, (2) assess the effects of opioid exposure on interneuron migration and neuronal function, (3) assess opioid-induced gene expression changes, and (4) test the effects of different drugs to restore opioid-related network dysfunction. By forming a collaborative, cross-displinary team, this synergistic partnership will address a significant barrier in the field of opioid abuse, which has the potential to lead to extramural funding and have translational impact.