SOX9-induced Generation of Functional Astrocytes Supporting Neuronal Maturation in an All-human System
Katrien Neyrinck, Johanna Van Den Daele, Tim Vervliet, Jonathan De Smedt, Keimpe Wierda, Melissa Nijs, Tom Vanbokhoven, Astrid D’hondt, Mélanie Planque, Sarah‐Maria Fendt, Pei‐Yu Shih, Frederik Seibt, Juan Pita Almenar, Mohamed Kreir, Devesh Kumar, Vania Broccoli, Geert Bultynck, Andreas Ebneth, Alfredo Cabrera‐Socorro, Catherine M. Verfaillie
Abstract
Astrocytes, the main supportive cell type of the brain, show functional impairments upon ageing and in a broad spectrum of neurological disorders. Limited access to human astroglia for pre-clinical studies has been a major bottleneck delaying our understanding of their role in brain health and disease. We demonstrate here that functionally mature human astrocytes can be generated by SOX9 overexpression for 6 days in pluripotent stem cell (PSC)-derived neural progenitor cells. Inducible (i)SOX9-astrocytes display functional properties comparable to primary human astrocytes comprising glutamate uptake, induced calcium responses and cytokine/growth factor secretion. Importantly, electrophysiological properties of iNGN2-neurons co-cultured with iSOX9-astrocytes are indistinguishable from gold-standard murine primary cultures. The high yield, fast timing and the possibility to cryopreserve iSOX9-astrocytes without losing functional properties makes them suitable for scaled-up production for high-throughput analyses. Our findings represent a step forward to an all-human iPSC-derived neural model for drug development in neuroscience and towards the reduction of animal use in biomedical research.