Figure 1.

Regulation of hematopoiesis by microbes. Left panel: Microbial components and metabolites derived from commensal microbes in the healthy gut maintain balanced hematopoiesis in the steady state. Middle panel: During infection, invading pathogens and their components induce myeloid-biased hematopoiesis (emergency myelopoiesis). Right panel: Myeloid-biased hematopoiesis during aging and under stress conditions such as obesity and type II diabetes may be a consequence of commensal microbial dysbiosis and intestinal permeability, which results in elevated levels of microbes and microbiome-derived components in the circulation.