Expression data from control, aged and activated neutrophils in mouse blood

Neutrophils provide immune protection against pathogens but also may promote tissue injury in inflammatory diseases. Although neutrophils are generally considered as a relatively homogeneous population, evidence for heterogeneity is emerging. Under steady-state conditions, neutrophil heterogeneity may arise from ageing and the replenishment by newly released neutrophils from the bone marrow. We used microarray to globally analyze gene expression in aged neutrophils and characterize the inflammatory programs that are activated during the aging process in the circulation. Control, aged and activated neutrophils were sorted directly from mouse blood for RNA extraction and hybridization on Affymetrix microarrays. We transfused whole blood and harvested donor neutrophils marked by the CD45.1 allele 6h later to derive neutrophils that had truly aged in vivo. Sorted neutrophils were compared to control donor neutrophils that had been transferred for only 10 min. Additionally, we harvested circulating neutrophils from TNF-α treated mice for comparison with neutrophils activated by systemic inflammation.