To establish an optimal protocol to obtain resting astrocytes derived from human induced pluripotent stem cells (hiPSC) and to examine how these cells react to multiple sclerosis (MS)-crucial cytokines.

Recent studies highlighted the importance of astrocytes in neuroinflammatory diseases, interacting closely with other CNS cells but also with the immune system. Regarding MS in particular, mouse models suggest that astrocytes are essential players in the disease and may exert a protective effect in the early phase but a deleterious effect during the chronic stage. However, due to the difficulty in obtaining human astrocytes, their role in the human disease is still poorly characterized.

Gene expression and functional assays show that our protocol consistently yields a highly enriched population of resting mature astrocytes across the thirteen hiPSC lines differentiated. Using this new model, we first highlight the importance of serum-free media for astrocyte culture to generate resting astrocytes. Second, we assess the astrocytic response to IL-1β, TNFα and IL-6, all cytokines important in neuroinflammation, such as multiple sclerosis.

Here, we developed a new serum-free protocol to differentiate human iPSCs into astrocytes. Our study reveals very specific profiles of reactive astrocytes depending on the triggering stimulus. This new model provides ideal conditions for in-depth and unbiased characterization of astrocyte reactivity in neuroinflammatory conditions.