Creating an environment that nurtures the trillions of beneficial microbes in our gut and, at the same time, protects us against invasion by food-borne pathogens is a challenge. A study published on August 8 in PLOS Pathogens reveals the role of a key player in this balancing act.
SIGIRR is a protein present at the surface of the cells that line the gut that dampens the innate (non-specific) immune response of these cells to bacteria. The new study, led by Xiaoxia Li (from the Lerner Research Institute in Cleveland, USA) and Bruce Vallance (from BC’s Childrens’ Hospital and the University of British Columbia in Vancouver, Canada), now shows that SIGIRR function in mice (and presumably also in humans) is necessary to protect the gut against “hostile takeover” by bacteria that cause serious food poisoning and bowel inflammation.
The researchers infected mice that were missing the Sigirr gene with bacterial pathogens that cause food poisoning in rodents (either a relative of toxic E. coli or Salmonella Typhimurium). And even though these mice had a much stronger intestinal innate immune response than mice with intact SIGIRR function, they were unable to defend themselves against the pathogens and got much sicker than their normal counterparts.
Primary source: PLOS Pathogens