Self-made antibiotics

Human angiogenin (ANG) is a protein with roles in tumor-associated angiogenesis, but its normal physiological function has been unclear. In the January 27 Nature Immunology, Lora V. Hooper and colleagues from Washington University School of Medicine, St. Louis, USA, show that human and mouse angiogenins constitute a new class of endogenous antimicrobial protein.

Hooper et al, worked on a simplified mouse model to study commensal host–bacterial interactions in the gut. They observed that mouse Paneth cells secreted into the gut lumen the angiogenin Ang4 — a previously uncharacterized bactericidal protein. Expression of Ang4 was induced by Bacteroides thetaiotaomicron (an intestinal commensal bacterium). In addition, the authors showed that mouse Ang1 and human ANG exhibit bactericidal and fungicidal activities against known bacterial and fungal pathogens.

"The species-selective microbicidal activities and differential expression patterns of Ang family members suggest that diversification of these genes was driven by selective pressures exerted...