A genetic screen identifies a protective type III interferon response toCryptosporidiumthat requires TLR3 dependent recognition

Autor: Adam Sateriale, Christopher A. Hunter, Daniel P. Beiting, Boris Striepen, Alexis R. Gibson, Jodi A. Gullicksrud, John G. Doench, Julie B. Engiles, Keenan O’Dea, Jennifer E. Dumaine
Rok vydání: 2021
Předmět:
Popis: Cryptosporidiumis a leading cause of severe diarrhea and diarrheal-related death in children worldwide. As an obligate intracellular parasite,Cryptosporidiumrelies on intestinal epithelial cells to provide a niche for its growth and survival, but little is known about the contributions that the infected cell makes to this relationship. Here we conducted a genome wide CRISPR/Cas9 knockout screen to discover host genes required forCryptosporidium parvuminfection and/or host cell survival. Gene enrichment analysis indicated that the host interferon response, glycosaminoglycan (GAG) and glycosylphosphatidylinositol (GPI) anchor biosynthesis are important determinants of susceptibility toC. parvuminfection. Several of these pathways are linked to parasite attachment and invasion and C-type lectins on the surface of the parasite. Evaluation of transcript and protein induction of innate interferons revealed a pronounced type III interferon response toCryptosporidiumin human cells as well as in mice. Treatment of mice with IFNλ reduced infection burden and protected immunocompromised mice from severe outcomes including death, with effects that required STAT1 signaling in the enterocyte. Initiation of this type III interferon response was dependent on sustained intracellular growth and mediated by the pattern recognition receptor TLR3. We conclude that host cell intrinsic recognition ofCryptosporidiumresults in IFNλ production critical to early protection against this infection.Author SummaryCryptosporidiuminfection is an important contributor to global childhood mortality. There are currently no vaccines available, and the only drug has limited efficacy in immunocompromised individuals and malnourished children who need it most. To discover which host proteins are essential forCryptosporidiuminfection, we conducted a genome wide knockout screen in human host cells. Our results confirm the importance of glycosaminoglycans on the surface of epithelial cells for attachment and invasion of the parasite. We also found that host GPI anchor biosynthesis and interferon signaling pathways were enriched by our screen. Examining the role of interferon signaling further we found a type III interferon response, IFNλ, was generated in response to infection and shown to be initiated in the infected cell. Utilizing mouse models of infection, we found that the type III interferon response was important early during infection with its induction likely preceding IFNγ, a key cytokine for the control of this infection. We also determined that TLR3 was the pattern recognition receptor responsible for IFNλ production duringCryptosporidiuminfection. Our work shows that IFNλ acts directly on the enterocyte and its use in treating immunocompromised mice produced striking reductions in infection.
Databáze: OpenAIRE