Leveraging Brain Organoids to Explore Congenital Central Hypoventilation Syndrome (CCHS)

The human brain is a complex organ, and its features of neurodevelopment and disease remain largely unexplored due to limited accessibility of living tissue. Recently, the human induced pluripotent stem cells (hiPSC) technology allowed to model the human brain in vitro, generating 3D organoids. We focused on the study of Congenital Central Hypoventilation Syndrome (CCHS). CCHS is a rare genetic disorder affecting the autonomic nervous system (ANS) and central chemosensitivity caused by the loss of retrotrapezoid nucleus (RTN) neurons in the brainstem. Mutations of the PHOX2B master gene affect the development of the ANS and central structures (RTN) that participate in breathing control. Given its fundamental role, CCHS animal models die in utero: to overcome this issue and have an insight in PHOX2B’s function during the first stages of human neurodevelopment, we used CCHS patient-derived iPSCs carrying different PHOX2B mutations. We developed brain and region-specific brainstem organoids (hBSOs), characterized them by fluorescent IHC to evaluate neuronal differentiation and brain regionalization, confirming that they contain cytoarchitectures resembling central chemoreceptors. This new personalized disease-in-a-dish model of CCHS will allow to identify molecular and cellular defects induced by PHOX2B mutations as well as modelling for drug discovery and screening for therapeutic perspectives.