Human pluripotent stem cell-derived microglia shape neuronal morphology and enhance network activity in vitro

Microglia, the resident immune cells of the central nervous system, play a critical role in maintaining neuronal health, but are often overlooked in traditional neuron-focused in vitro models. In this study, we developed a novel co-culture system of human pluripotent stem cell (hPSC)-derived microglia and neurons to investigate how hPSC-derived microglia influence neuronal morphology and network activity. Using high-content morphological analysis and multi-electrode arrays (MEA), we demonstrate that these microglia successfully incorporate into neuronal networks and modulate key aspects of neuronal function. hPSC-derived microglia significantly reduced cellular debris and altered neuronal morphology by decreasing axonal and dendritic segments and reducing synapse density. Interestingly, despite the decrease in synapse density, neuronal network activity increased. Our findings underscore the importance of including hPSC-derived microglia in in vitro models to better simulate in vivo neuroglial interactions and provide a platform for investigating neuron-glia dynamics in health and disease. • Developed a novel co-culture model of hPSC-derived microglia and neurons. • hPSC-derived microglia reduced cellular debris and influenced neuronal morphology in co-cultures. • hPSC-derived microglia decreased synapse density but increased neuronal network activity. • This model provides a platform for studying neuron-glia dynamics in health and disease.