Genome-wide CRISPRi Screen in Human iNeurons to Identify Novel Focal Cortical Dysplasia Genes.
Andrew M TidballJinghui LuoJ Clayton WalkerTaylor N TaklaGemma L CarvillJack M ParentPublished in: bioRxiv : the preprint server for biology (2023)
Focal cortical dysplasia (FCD) is a common cause of focal epilepsy that typically results from brain mosaic mutations in the mTOR cell signaling pathway. To identify new FCD genes, we developed an in vitro CRISPRi screen in human neurons and used FACS enrichment based on the FCD biomarker, phosphorylated S6 ribosomal protein (pS6). Using whole-genome (110,000 gRNAs) and candidate (129 gRNAs) libraries, we discovered 12 new genes that significantly increase pS6 levels. Interestingly, positive hits were enriched for brain-specific genes, highlighting the effectiveness of using human iPSC-derived induced neurons (iNeurons) in our screen. We investigated the signaling pathways of six candidate genes: LRRC4 , EIF3A, TSN, HIP1, PIK3R3, and URI1 . All six genes increased phosphorylation of S6. However, only two genes, PIK3R3 and HIP1, caused hyperphosphorylation more proximally in the AKT/mTOR/S6 signaling pathway. Importantly, these two genes have recently been found independently to be mutated in resected brain tissue from FCD patients, supporting the predictive validity of our screen. Knocking down each of the other four genes ( LRRC4, EIF3A, TSN, and URI1 ) in iNeurons caused them to become resistant to the loss of growth factor signaling; without growth factor stimulation, pS6 levels were comparable to growth factor stimulated controls. Our data markedly expand the set of genes that are likely to regulate mTOR pathway signaling in neurons and provide additional targets for identifying somatic gene variants that cause FCD.
Keyphrases
- genome wide
- growth factor
- signaling pathway
- genome wide identification
- dna methylation
- bioinformatics analysis
- endothelial cells
- copy number
- randomized controlled trial
- genome wide analysis
- high throughput
- cell proliferation
- spinal cord
- epithelial mesenchymal transition
- end stage renal disease
- induced pluripotent stem cells
- pi k akt
- resting state
- chronic kidney disease
- systematic review
- transcription factor
- stem cells
- functional connectivity
- newly diagnosed
- prognostic factors
- electronic health record
- oxidative stress
- bone marrow
- protein protein
- atomic force microscopy