The influence of microbiota-derived metabolites on viral infections.

Intestinal microbiota have profound effects on viral infections locally and systemically. While they can directly influence enteric virus infections, there is also an increasing appreciation for the role of microbiota-derived metabolites in regulating virus infections. Because metabolites diffuse across the intestinal epithelium and enter circulation, they can influence host response to pathogens at extraintestinal sites. In this review, we summarize the effects of three types of microbiota-derived metabolites on virus infections. While short-chain fatty acids serve to regulate the extent of inflammation associated with viral infections, the flavonoid desaminotyrosine and bile acids generally regulate interferon responses. A common theme that emerges is that microbiota-derived metabolites can have proviral and antiviral effects depending on the virus in question. Understanding the molecular mechanisms by which microbiota-derived metabolites impact viral infections and the highly conditional nature of these responses should pave the way to developing novel rational antivirals.