Image of the Day: Flushing the Gut

In response to a bacterial infection, an immune signal in mice's guts triggers a molecular cascade that promotes diarrhea, which, researchers demonstrate, is important for ridding them of the bacteria.  

Jun 19, 2017
The Scientist Staff

An immunofluorescence microscopy image depicts the intestinal lumen of a mouse lacking claudin-2, a diarrhea-inducing tight junction protein. In these deficient mice, C. rodentium bacteria (red) infiltrate the intestines. DNA stained in blue; F-actin (denoting cells' external-facing surfaces) in green.

TURNER LABORATORY AT BRIGHAM AND WOMEN’S HOSPITAL

           Scientists investigating the functional role of diarrhea found that bacterial pathogens stimulate the immune signaling protein IL-22, which increases claudin-2 expression and facilitates the outflow of water and subsequently, diarrhea. According to a news release, this “play[s] a critical role in pathogen clearance in the early stages of infection.”

See P.-Y. Tsai et al., “IL-22 upregulates epithelial claudin-2 to drive diarrhea and enteric pathogen clearance,” Cell Host & Microbe, doi:10.1016/j.chom.2017.05.009, 2017.