Cell-based screen identifies human type I interferon-stimulated regulators ofToxoplasma gondiiInfection

Abstract

AbstractMacrophages activated with interferons (IFNs) respond with transcriptional changes that enhance clearance of intracellular pathogens such asToxoplasma, a ubiquitous apicomplexan parasite that infects more than a billion people worldwide. Although IFNs generally inhibitToxoplasma, the parasite can also induce components of the host IFN signalling pathway to enhance survival in host cells. Compared to the type II IFN gamma (IFNγ), the role of type I IFNs in macrophage response toToxoplasmais relatively not well characterized. Here, using fluorescentToxoplasmaand a CRISPR/Cas9 knockout library that only targets interferon-stimulated genes (ISGs), we adapted a loss-of-function flow cytometry-based approach to systematically identify type I ISGs that controlToxoplasmagrowth in THP-1 cells, a human macrophage cell line. The system enabled the rapid screening of more than 1900 ISGs for type I (IFNα)-induced inhibitors and enhancers ofToxoplasmagrowth in THP-1 cells. We identified 26 genes that are associated withToxoplasmagrowth arrest out of which we confirmedMAX, SNX5, F2RL2, andSSB, as potent IFNα-induced inhibitors ofToxoplasmain THP1 cells. These findings provide a genetic and experimental roadmap to elucidate type I IFN-induced cell-autonomous responses toToxoplasma.