LAUSR

Summary There is a growing body of research on the neural control of immunity and inflammation. However, it is not known whether the nervous system can regulate the production of inflammatory myeloid cells from hematopoietic progenitor cells in disease conditions. Myeloid cell numbers in diabetic patients were strongly correlated with plasma concentrations of norepinephrine, suggesting the role of sympathetic neuronal activation in myeloid cell production. The spleens of diabetic patients and mice contained higher numbers of tyrosine hydroxylase (TH)‐expressing leukocytes that produced catecholamines. Granulocyte macrophage progenitors (GMPs) expressed the &bgr;2 adrenergic receptor, a target of catecholamines. Ablation of splenic sympathetic neuronal signaling using surgical, chemical, and genetic approaches diminished GMP proliferation and myeloid cell development. Finally, mice lacking TH‐producing leukocytes had reduced GMP proliferation, resulting in diminished myelopoiesis. Taken together, our study demonstrates that catecholamines produced by leukocytes and sympathetic nerve termini promote GMP proliferation and myeloid cell development. Graphical Abstract Figure. No caption available. HighlightsSympathetic nervous system (SNS) mediates differentiation of myeloid progenitorsTH+ leukocytes express high amounts of neuropeptide Y receptors (NPYRs)TH+ cells are required for myeloid cell generation during “emergency” hematopoiesisRegulation of myelopoiesis by the &bgr;2 adrenergic receptor expressed by GMPs &NA; Neural control of immunity and inflammation has been reported. Vasamsetti and colleagues demonstrate that the sympathetic nervous system controls the development of inflammatory myeloid cells from their progenitors in inflammatory conditions.