Gut bacteria produce small organic compounds known as N-acyl amides that interact with receptors to mediate human health and physiology, research published online in Nature this week suggests. N-acyl amides are an important class of human signalling molecule that has been implicated in various aspects of physiology, including immunology, behaviour and metabolism.

Although the human microbiome is thought to have an important role in physiology and health, the underlying mechanisms remain poorly understood. Bacteria rely on small molecules to interact with their environment and it has been suggested that the human microbiota also uses small molecules to interact with its human host. However, the identity of the potential molecules involved and how they function has been unknown.

Sean Brady and colleagues report that human gut bacteria produce N-acyl amides that interact with five different human G-protein-coupled receptors (GPCRs; a family of membrane proteins that are common drug targets). The authors analyse mouse- and cell-based data and show that these bacterial metabolites activate a GPCR known as GPR119 and that they have the potential to regulate metabolic hormones and glucose homeostasis in mice. The findings suggest that small molecules produced by the microbiota can mimic bacterial signalling molecules, and that this mimicry may represent an avenue that could potentially be exploited in future therapeutic strategies for the treatment of diseases, such as diabetes and obesity.