Protocol for pooled FACS-based CRISPR knockout screening in human iPSC-derived microglia

Here, we present a protocol for CRISPR knockout screening in human induced pluripotent stem cell (hiPSC)-derived microglia (iMGL) using lentiviral delivery of CRISPR-Cas9 and co-transduction of VPX virus-like particles (VPX-VLPs). We first describe large-scale production of iMGL from hiPSCs, production of the lentiviral and VPX-VLP libraries, and titration. Next, we describe how to perform a pooled CRISPR screen for phagocytosis including the computational analysis pipeline of CRISPR screening data. For complete details on the use and execution of this protocol, please refer to Perez-Alcantara et al.1. Keywords: CRISPR; cell culture; high-throughput screening; sequencing; stem cells.