Rountree, C. | Search bioRxiv

bioRxiv2025

Long-Term Potentiation and Closed-Loop Learning in Paired Brain Organoids for CNS Drug Discovery

Learning and memory, central to cognitive function and critical targets for drug discovery in neurological disorders, fundamentally rely on synaptic plasticity, such as long-term potentiation (LTP). We developed an embedded electrode array (EEA) capable of supporting paired CNS-3D brain organoids, derived from human, induced pluripotent stem cells (iPSCs), that were interconnected via guided axonal growth, as a novel functional biomarker model for probing learning-related plasticity in vitro. Using open-loop stimulation protocols, a robust, network-level LTP in trained organoids was demonstrated that was not observed in untrained organoids. Importantly, LTP was enhanced in the presence of elevated levels of brain-derived neurotrophic factor (BDNF), and it was prevented by the NMDA receptor antagonist AP5. Furthermore, a closed-loop "maze-game", inspired by Pac-Man(R), demonstrated that paired brain organoids could learn to perform better in the game when given reinforcement feedback, and that this effect depended on BDNF. This integrated platform provides a human-relevant in vitro model of synaptic plasticity and cognitive function, establishing a functional biomarker platform for central nervous system (CNS) drug discovery and linking game performance as a measurable readout of learning-related plasticity to the emerging field of organoid intelligence.

bioengineering↗

bioRxiv2025

Human Peripheral Nerve-on-a-Chip on a Multiwell Microelectrode Array as a Scalable Preclinical Neurotoxicity Assay

Reliable human-relevant models of peripheral nerve function remain a critical unmet need in preclinical drug development, particularly for predicting neurotoxicity and bridging the gap to clinical translation. Here, we introduce a next generation Nerve-on-a-Chip, PNS-3D organoids, as a novel human-cell-based 3D peripheral nerve microphysiological system (MPS) that recapitulates key functional and structural features of native nerves, including long-distance axonal outgrowth, physiological myelination, and clinically translational population level electrophysiology. The platform integrates iPSC-derived human sensory neurons and primary human Schwann cells within a spatially organized 3D environment, coupled to a custom embedded electrode array that enables high-content, longitudinal, and clinically translatable functional assessments. As a proof of concept, we evaluated the platforms predictive power using vincristine, a chemotherapeutic agent known to cause chemotherapy-induced peripheral neuropathy (CIPN). PNS-3D organoids captured dose- and time-dependent deficits in nerve conduction velocity, compound action potential amplitude, and axonal degeneration, with IC values in line with human clinical exposures-- outperforming traditional 2D cultures and in vivo benchmarks. Transcriptomic and morphological analyses further revealed neuron-specific degeneration consistent with axonopathy. These results validate the platform as a human-relevant, clinically translation, and scalable solution, enabling mechanistic safety assessment and drug discovery for neurotoxic and neuroprotective therapeutics.

pharmacology and toxicology↗