An efficient lentiviral CRISPRi approach to silence genes in primary human monocytes

Human primary monocytes are critical in controlling immune responses and tissue homeostasis. However, to identify and study molecular components that underlie the function of these cells, there remains a need to develop methods to perturb genes in these cells. Here we report lentiviral-based delivery of dCas9-KRAB and guide RNAs to efficiently silent target genes, such as CD45 and CD209. We further show that sgRNAs against TICAM1 dampen proinflammatory cytokine and interferon expression in response to lipopolysaccharide. When delivered by lentivirus, sgRNAs are incorporated into the genome, thus enabling pooled screening to perturb and identify coding and non-coding elements that contribute to the functions of primary human monocytes.