Rhythmic Modulation of the Hematopoietic Niche
In a current publication in Cell, Andres Hidalgo and colleagues, including SFB 914 principal investigator Christian Weber, describe that the clearance of aged neutrophils from the circulation by macrophages in the bone marrow is coupled to the systemic egress of hematopoietic precursors from their niche.
Neutrophil clearance influences hematopoietic niche
Unique among leukocytes, neutrophils follow daily cycles of release from and migration back into the bone marrow, where they are eliminated. Because removal of dying cells generates homeostatic signals, the authors explored whether neutrophil elimination triggers circadian events in the steady state.
The authors report that the homeostatic clearance of neutrophils provides cues that modulate the physiology of the bone marrow. They identify a population of CD62LLO CXCR4HI neutrophils that have “aged” in the circulation and are eliminated at the end of the resting period in mice.
Aged neutrophils infiltrate the bone marrow and promote reductions in the size and function of the hematopoietic niche. Modulation of the niche depends on macrophages and activation of cholesterol-sensing nuclear receptors and is essential for the rhythmic egress of hematopoietic progenitors into the circulation.
The published results unveil a process that synchronizes immune and hematopoietic rhythms and expand the ascribed functions of neutrophils beyond inflammation.
Casanova-Acebes M, Pitaval C, Weiss LA, Nombela-Arrieta C, Chèvre R, A-González N, Kunisaki Y, Zhang D, van Rooijen N, Silberstein LE, Weber C, Nagasawa T, Frenette PS, Castrillo A, Hidalgo A. (2013)
Rhythmic Modulation of the Hematopoietic Niche through Neutrophil Clearance.
Prof. Dr. med. Christian Weber
Institut für Prophylaxe und Epidemiologie der Kreislaufkrankheiten (IPEK)
Klinikum der Universität München
Tel.: +49 (0)89-5160-4351