Rotavirus, a leading cause of severe gastroenteritis and diarrhoea in young children, accounts for around 215,000 deaths annually worldwide. Rotavirus specifically infects the intestinal epithelial cells in the host small intestine and has evolved strategies to antagonize interferon and NF-κB signalling, raising the question as to whether other host factors participate in antiviral responses in intestinal mucosa. The mechanism by which enteric viruses are sensed and restricted in vivo, especially by NOD-like receptor (NLR) inflammasomes, is largely unknown. Here we uncover and mechanistically characterize the NLR Nlrp9b that is specifically expressed in intestinal epithelial cells and restricts rotavirus infection. Our data show that, via RNA helicase Dhx9, Nlrp9b recognizes short double-stranded RNA stretches and forms inflammasome complexes with the adaptor proteins Asc and caspase-1 to promote the maturation of interleukin (Il)-18 and gasdermin D (Gsdmd)-induced pyroptosis. Conditional depletion of Nlrp9b or other inflammasome components in the intestine in vivo resulted in enhanced susceptibility of mice to rotavirus replication. Our study highlights an important innate immune signalling pathway that functions in intestinal epithelial cells and may present useful targets in the modulation of host defences against viral pathogens.
Pubmed ID: 28636595 RIS Download
Mesh terms: Animals | Apoptosis Regulatory Proteins | CARD Signaling Adaptor Proteins | Caspase 1 | DEAD-box RNA Helicases | Epithelial Cells | Female | Immunity, Innate | Inflammasomes | Interleukin-18 | Intestines | Male | Mice | Mice, Inbred C57BL | Pyroptosis | RNA, Double-Stranded | Receptors, G-Protein-Coupled | Rotavirus | Rotavirus Infections
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Center that produces knockout mice and carries out high-throughput phenotyping of each line in order to determine the function of every gene in the mouse genome. These mice will be preserved in repositories and made available to the scientific community representing a valuable resource for basic scientific research as well as generating new models for human diseases.
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