Microbial trash to metabolic treasure.

In a recent publication, Lesbats et al uncover the molecular fate of phagocytosed bacterial contents. The authors observed incorporation of bacterial biomolecules (amino acids, metabolites) into those of the host macrophage through stable isotope labeling and mass spectrometry. Further, the authors found that the state of the phagocytosed bacteria, living or dead, dramatically alters the macrophage's metabolic program toward either a pro-inflammatory or a "recycling" direction, respectively. This commentary summarizes these findings and further discusses the implications of this work in a broader sense.