Expression of interleukin-8 by lipopolysaccharide-stimulated bone marrow-derived mononuclear cells.
Interleukin-8 (IL-8) is a potent neutrophil chemoattractant, produced by a variety of immune and nonimmune cells in response to exogenous and host-derived inflammatory stimuli. We demonstrate here that a suspension of normal bone marrow mononuclear cells, consisting principally of myeloid precursors, produces IL-8 in response to stimulation with lipopolysaccharide (LPS). IL-8-specific mRNA is rapidly induced, being detected first 30 min after stimulation. IL-8 is detected by enzyme-linked immunosorbent assay within 2 h of stimulation, with steady a increase in its level through 72 h. Further studies demonstrated that LPS could serve as a primary stimulus for the expression of IL-8, since LPS challenge in the presence of cycloheximide resulted in superinduction of bone marrow mononuclear cell-derived IL-8 mRNA. These investigations suggest that the stimulatory effect of LPS is independent of other cytokines such as IL-1 beta. When compared with LPS, IL-1 beta proved to be a weak signal for the expression of IL-8 by bone marrow mononuclear cells. In a dose-response study, the maximum stimulatory concentration of IL-1 beta (300 pg/ml) resulted in the production of 500 pg of IL-8 per 10(6) cells, whereas 1 microgram of LPS resulted in the production of 5.5 ng/10(6) cells. Although IL-1 beta was not a particularly potent stimulus for IL-8 production by bone marrow mononuclear cells, peripheral blood mononuclear cells were highly susceptible to IL-1 beta challenge. In addition, the potential dependence of LPS-induced marrow-derived IL-8 production on the intermediate synthesis of IL-1 beta was further investigated. Results of studies assessing kinetics, addition of cycloheximide, and blocking with IL-1 beta neutralizing antibody were all consistent with the ability of LPS to directly induce bone marrow-derived IL-8 independently of IL-1 beta. These investigations demonstrate that bone marrow may be a significant source of IL-8 and may play a significant role in acute infectious, inflammatory responses.
Dibb
C R
CR
Department of Internal Medicine, University of Michigan Medical School, Ann Arbor 48109-0602.
Strieter
R M
RM
Burdick
M
M
Kunkel
S L
SL
D001483:Base Sequence; D001853:Bone Marrow / Q000378:metabolism*; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D006801:Humans; D007375:Interleukin-1 / Q000235:genetics; D016209:Interleukin-8 / Q000096:biosynthesis* / Q000235:genetics; D007700:Kinetics; D008070:Lipopolysaccharides; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis
D007375:Interleukin-1; D016209:Interleukin-8; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D003513:Cycloheximide