DECIPHERING PSYCHIATRIC DISEASE ASSOCIATED CHANGES IN HUMAN NEURONS BY COMBINATORIAL GENE KNOCKDOWN

Schizophrenia (SCZ) is a complex brain disorder that is heterogeneous among affected individuals not only in its clinical presentation but also its high polygenic nature. The large variation in how the disease manifests makes it difficult to pinpoint one biological pathway to treat. Therefore, a key step in gaining a better understanding of SCZ is to disentangle the contribution of various genes. To this end, we study human induced pluripotent stem cell-derived neurons in which several SCZ-associated genes are knocked down simultaneously. Using RNA interference to reduce gene expression, we validated the knockdown with a combination of several genes. Then, we investigated how multiple downregulated risk genes influence neuronal development by screening for certain endophenotypes such as alterations in neurite morphology and synapse formation, as well as performing an unbiased phenotypic profiling with the Cell Painting assay. Bioinformatic analyses of this data can reveal synergistic or additive effects. For example, some genes that do not have a significant effect at the individual level may have more pronounced effects at the group level, suggesting a functional relationship between them. In summary, gene interactions driving morphological changes that deviate from the control can provide insight into dysregulated biological pathways underlying psychiatric disorders. Disease signatures generated through high-throughput imaging, along with a functional interaction map of selected SCZ-related genes, will be valuable for further applications such as target-agnostic compound screening.