Recurrent infection progressively disables host protection against intestinal inflammation

Abstract

Minor infections cause big problems Pathogenic infection has been implicated in the chronic inflammation seen in inflammatory bowel diseases (IBDs) such as ulcerative colitis and Crohn's disease. Yang et al. show that recurrent, low-level, and fully resolving Salmonella enterica Typhimurium (ST) infections can precipitate severe colonic inflammation in mice. ST-induced TLR4 activation resulted in increased neuraminidase 3 (Neu3) production and activity in the duodenum. This led to intestinal alkaline phosphatase (IAP) desialylation and degradation. IAP deficiency caused a marked increase in commensal bacteria-generated lipopolysaccharide-phosphate in the colon, provoking inflammation. Treatment with calf IAP or the antiviral drug zanamivir (which inhibits Neu3 activity) prevented this inflammatory cascade. This pathway may serve as an effective target for future human IBD therapies. Science , this issue p. eaao5610