Patterning ganglionic eminences in developing human brain organoids using morphogen gradient inducing device
In early neurodevelopment, the central nervous system is established through the coordination of various neural organizers directing tissue patterning and cell differentiation. Better recapitulation of morphogen gradient production and signaling will be crucial for establishing improved developmental models of the brain in vitro. Here, we developed a method by assembling polydimethylsiloxane (PDMS) devices capable of generating a sustained chemical gradient to produce patterned brain organoids, which we termed Morphogen-gradient Induced Brain Organoids (MIBOs). At 3.5 weeks, MIBOs replicated Dorsal-Ventral patterning observed in the Ganglionic Eminence (GE). Analysis of matured MIBOs through single-cell RNA sequencing revealed distinct Dorsal GE derived CALB2+ interneurons (INs), Medium Spiny Neurons (MSNs), and MGE derived cell types. Finally, we demonstrate long term culturing capabilities with MIBOs maintaining stable neural activity in cultures grown up to 5.5 months. MIBOs demonstrate a versatile approach for generating spatially patterned brain organoids for embryonic development and disease modeling. MotivationThe use of small molecules for the guided differentiation of brain organoids has proven to be a useful tool for modeling various aspects of early neurodevelopment. Still, the embryonic brain is patterned through a combination of morphogen gradients stemming from organizer regions. To address this inconsistency, we designed a device capable of mimicking neural organizers by maintaining a steady morphogen gradient. We used this device to expose forebrain organoids to multiple gradient conditions and cataloged the diversity of cell types produced.