Air-liquid interface culture of midbrain organoids improves neuronal functionality and integration of microglia

Midbrain organoids derived from human induced pluripotent stem cells have emerged as a promising in vitro model for studying the molecular and cellular mechanisms in Parkinson’s disease. However, the absence of microglia and the development of a necrotic core in mature organoids have remained key limitations on their utility as functional models of the human midbrain. Here we propose a novel methodology for extended cultivation of midbrain organoid slices, which involves the incorporation of microglia and utilizes an air-liquid culture system. Compared to conventional whole organoids, we found that our model increased the efficacy and consistency of the integration of microglia progenitors. Using single-cell RNA sequencing, we showed that organoid slices maturated in ALI give rise to astrocytes and oligodendrocyte progenitors. Furthermore, the cultivation in air-liquid interface greatly improved neuronal functionality in response to stimulation by NMDA. This stimulation consistently induced robust and stable network activity evaluated by microelectrode array recording. Our newly developed midbrain organoid model with its improved cell type composition and neuronal functionality has potential applications in basic research of Parkinson’s disease and in the development of therapeutics. ![Figure][1] ### Competing Interest Statement The authors have declared no competing interest. [1]: pending:yes