High throughput identification of genetic regulators of microglial inflammatory processes in Alzheimer's disease.

We sought to assess at scale how AD GWAS hits influence human microglial inflammatory responses. We conducted CRISPR inhibition screens of 119 AD GWAS hits in parallel along with 52 control genes in human iPSC-derived microglia, with reactive oxygen species produced in response to the viral mimic poly(I:C) as a readout. Top hits that either decreased or increased ROS in response to poly(I:C) when knocked down were then interrogated via perturb-seq. Overall design: Human iPS-derived microglia were infected with sgRNA targeting hit of interest on day 21. Cells were treated with either vehicle or poly(I:C) on day 35 for 2 hours and collected for single-cell RNA-sequencing. CRISPR guide libraries were also generated for downstream analysis.