KCTD20 suppression mitigates excitotoxicity in tauopathy patient organoids

Excitotoxicity is a major pathologic mechanism in patients with tauopathy and other neurodegenerative diseases. However, the key neurotoxic drivers and most effective strategies for mitigating these degenerative processes are unclear. Here, we show that glutamate treatment of induced pluripotent stem cell (iPSC)-derived cerebral organoids induces tau oligomerization and neurodegeneration, and that these phenotypes are enhanced in organoids derived from tauopathy patients. Using a genome-wide CRISPR interference (CRISPRi) screen, we find that suppression of KCTD20 potently ameliorates tau pathology and neurodegeneration in glutamate-treated organoids and mice, as well as in transgenic mice overexpressing mutant human tau. KCTD20 suppression reduces oligomeric tau and improves neuron survival by activating lysosomal exocytosis, which clears pathological tau. Our results show that glutamate signaling can induce neuronal tau pathology and identify KCTD20 suppression and lysosomal exocytosis as effective strategies for clearing neurotoxic tau species. Overall design: ASO-treated wildtype, isogenic, and MAPT V337M mutant organoids were collected 3 or 6 days after glutamate treatment for scRNA seq. Conditions were multiplexed to save on cost. Please note that processed data generated from both replicate (e.g. *A*B*.gz files) are linked to the corresponding first replicate '*glut 1' sample record.