On macrophage diversity and inflammatory metabolic timers

Key papers were published in 2019 that solidify the notion that macrophage gene expression is remarkably diverse; single-cell sequencing combined with new macrophage-specific genetic tools has provided unexpected insights into the tissue-specific and inflammatory diversity of macrophages. In addition, a new mechanism of inflammatory control of macrophage diversity based on lactate-mediated histone modifications was discovered. In 2019, single-cell sequencing studies provided important insight into the diverse gene expression profiles of tissue macrophages, and new systems for specifically deleting macrophages were reported. A lactate ‘timer’ that controls inflammatory responses in macrophages was also described.