Inhibition by dexamethasone of the lipopolysaccharide-induced increase in IL-6 mRNA abundance and IL-6 production in human polymorphonuclear leukocytes.
Interleukin-6 (IL-6) is a key inflammatory cytokine that is produced by various cell types including polymorphonuclear leukocytes (PMNs). However, the pathophysiological roles of IL-6 produced by human PMNs are unclear. Bacterial lipopolysaccharide (LPS) induced marked increase in IL-6 production, determined by enzyme-linked immunosorbent assay, and IL-6 mRNA abundance determined by reverse transcription-polymerase chain reaction analysis, in purified human PMNs. Both effects of LPS were inhibited in a dose-dependent manner by dexamethasone (10(-6) to 10(-8) M). IL-6 receptor mRNA was constitutively present in PMNs and its abundance was not affected by either LPS or dexamethasone. These results indicate that PMNs are an important source of IL-6 in acute inflammatory reactions, and that the anti-inflammatory actions of dexamethasone is attributable in part to inhibition of IL-6 production by these cells. The constitutive presence of IL-6 receptor mRNA in PMNs suggests that IL-6 may exert pathophysiological effects on these cells.
Mianji
S
S
Department of Pediatrics, Saga Medical School, Japan.
Hamasaki
Y
Y
Yamamoto
S
S
Miyazaki
S
S
D003907:Dexamethasone / Q000494:pharmacology*; D006801:Humans; D015850:Interleukin-6 / Q000096:biosynthesis*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D012333:RNA, Messenger / Q000037:antagonists & inhibitors* / Q000096:biosynthesis*; D000093242:Interleukin-6 Inhibitors
D003907:Dexamethasone; D015850:Interleukin-6; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D000093242:Interleukin-6 Inhibitors