Abstract
Shigellosis, the primary cause of diarrheal deaths worldwide, particularly affects children living in low and middle-income countries1. The causative agent, Shigella spp., invades and replicates in the epithelium of the large intestine, eliciting an intense inflammatory response and tissue destruction2. However, how Shigella rewires macrophages prior to epithelial cell invasion3 is poorly understood. Here we show that Shigella flexneri induces the production of pro-inflammatory cytokines and chemokines and triggers host pyruvate catabolism for energy acquisition before rapidly killing macrophages. To identify host factors modulated by S. flexneri, we performed genome-wide and focused secondary CRISPR knockout and CRISPRi screens in human monocytic THP-1 cells infected with S. flexneri and evaluated host cell survival. Knockdown of key components of the Toll-like receptor 1/2 signaling pathway significantly reduced pro-inflammatory cytokine and chemokine production, enhanced host cell survival, and controlled intracellular pathogen growth. Knockdown of the enzymatic component of the mitochondrial pyruvate dehydrogenase complex also enhanced THP-1 cell survival. Small molecule inhibitors, which selectively inhibit key components of these pathways, enhanced host survival and limited intracellular pathogen growth. High-throughput CRISPR screens provide insights into the specific effects of S. flexneri on macrophages; these insights can potentially guide development of new therapies for shigellosis.
Competing Interest Statement
T.K.L. is a co-founder of Senti Biosciences, Synlogic, Engine Biosciences, Tango Therapeutics, Corvium, BiomX, and Eligo Biosciences. T.K.L. also holds financial interests in nest.bio, Ampliphi, IndieBio, MedicusTek, Quark Biosciences, and Personal Genomics. Y.L. and T.K.L. are co-inventors on a US provisional patent application (no. 62/909727), which is based on discoveries described in this paper.