A HARMLESS gut bacterium has yielded up a secret that could herald new treatments for inflammatory bowel disease and other chronic gut disorders.
The abundant gut bacterium Bacteroides thetaiotaomicron has an unexpected knack for soothing inflammation that occurs after the gut鈥檚 immune system has dealt with dangerous bacteria. The guts of patients with inflammatory bowel disease lack this response, so the hope is that it might be possible to treat the condition with drugs that mimic the bacterial trick, or even by simply eating the friendly bacteria.
Through experiments on cell cultures and in rats, Denise Kelly and her colleagues at the Rowett Research Institute in Aberdeen, Scotland, discovered that B. thetaiotaomicron calms inflammation by sending chemical signals to the epithelial cells that line the gut. The signals deactivate nuclear factor-kappa B (NF-&kgr;B), a molecular master switch that controls genes linked with inflammation.
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Inflammation genes can only be activated if NF-&kgr;B is transported into the cell鈥檚 nucleus from the surrounding cellular fluid, where it is normally stored. Kelly鈥檚 team reports that B. thetaiotaomicron somehow orders the gut cells to produce a second protein that keeps NF-&kgr;B harmlessly outside the nucleus (Nature Immunology, DOI: 10.1038/ni1018). 鈥淲e hope to make drugs that do the same thing,鈥� says Kelly.