Glutamine addiction is a therapeutic target to block emergency myelopoiesis.

Inflammation-driven emergency myelopoiesis (EM) contributes to the progression of many solid cancers and inflammatory diseases, yet therapeutic strategies to selectively suppress EM without compromising hematopoiesis remain lacking. Here, we use functional and single-cell transcriptomic analyses to determine metabolic programs organizing the hematopoietic hierarchy, myeloid lineage commitment, and myeloid differentiation. We identify de novo glutamine biosynthesis as a stem cell-specific survival mechanism allowing independence from exogenous glutamine. We show that myeloid differentiation is characterized by Myc-driven upregulation of mitochondrial respiration, which is hyperactivated during EM and renders myeloid progenitors dependent on glutaminolysis to fuel the TCA cycle. Both genetic and pharmacologic targeting of glutaminase suppresses EM and impairs breast tumor progression by reducing intratumoral neutrophil infiltration. Our study defines a central role for Myc-glutaminolysis in driving EM, identifies glutaminolysis as a therapeutic target to normalize maladaptive EM, and highlights myeloid overproduction as a systemic problem requiring HSPC targeting.