KCNJ2 inhibition mitigates mechanical injury in human brain organoids

Traumatic brain injury (TBI) strongly correlates with neurodegenerative disease. However, it remains unclear which neurodegenerative mechanisms are intrinsic to the brain itself and which strategies most potently mitigate these processes, particularly in individuals genetically predisposed to neurodegeneration. We developed a high-intensity ultrasound platform to inflict mechanical injury to iPSC-derived cortical organoids. Mechanically injured organoids elicit several classic hallmarks of TBI including neuron death, tau phosphorylation, and TDP-43 phosphorylation and nuclear egress. We found that deep layer excitatory neurons were particularly vulnerable to injury and that TDP-43 proteinopathy promotes loss-of-function and cell death. Injured organoids derived from C9ORF72 amyotrophic lateral sclerosis/frontotemporal dementia (ALS/FTD) patients displayed exacerbated TDP-43 dysfunction. Using genome-wide CRISPR interference screening, we identified a mechanosensory channel, KCNJ2, whose inhibition potently mitigated neurodegenerative processes in vitro and in vivo, including in C9ORF72 ALS/FTD organoids. Thus, targeting KCNJ2 may reduce acute neuron death after brain injury, and we present a scalable, genetically-flexible cerebral organoid model that may enable identification of additional modifiers downstream of mechanical stress.