Gut sensor halts viral attack

Abstract

Intestinal infection with rotavirus is a major cause of diarrhoea in infants, and can be fatal. The identification of immune sensor proteins that detect and restrict this viral infection now illuminates the body's defence system. See Letter p.667 Rotaviruses cause severe and often fatal gastroenterological illnesses in young children. The mechanism by which such enteric viruses are detected and restricted in vivo is largely unknown. Richard Flavell and colleagues report how the inflammasome receptor Nlrp9 helps to defend against enteric viruses, via RNA helicase Dhx9, by interacting with double-stranded viral RNA. This interaction triggers gasdermin-D-dependent pyroptotic cell death of infected cells and secretion of IL-18. This innate immune signalling functions uniquely in intestinal epithelial cells and could reveal useful targets in the modulation of viral defences.