Hyperosmotic stress as a stimulant for proinflammatory cytokine production.
The synthesis of proinflammatory cytokines involves members of the mitogen-activated protein (MAP) kinase stress pathway, particularly p38 MAP kinase and c-jun NH2-terminal kinase. In this report we used hyperosmotic stress to study changes in steady-state mRNA levels and synthesis of proinflammatory cytokines in freshly obtained human peripheral blood mononuclear cells (PBMC) in vitro. There was no evidence of interleukin (IL)-8 gene expression in freshly obtained human blood despite 30 cycles of amplification of reverse-transcribed mRNA using the polymerase chain reaction. In contrast, exposure of PBMC to hyperosmotic conditions (330-410 mOsM) by the addition of NaCl to tissue culture medium induced gene expression for IL-1 alpha, IL-1 beta, and IL-8. Routine tissue culture medium is hyperosmotic (305 mOsM) compared to human plasma (280-295 mOsM), but decreasing the osmolarity to the physiological range resulted in a 50% reduction in baseline IL-8 synthesis (P < 0.001). Although hyperosmotically induced accumulation of steady-state mRNA levels for IL-1 alpha and IL-1 beta increased 50- and 7-fold over control, respectively, these were poorly translated into each respective cytokine. However, in PBMC stimulated by hyperosmotic stress, the addition of femtomolar concentrations of bacterial lipopolysaccharide, IL-1, or 1% normal human serum resulted in a synergistic synthesis (at least twice that expected) of IL-1 alpha, IL-1 beta, TNF-alpha, and IL-8.
Shapiro
L
L
Department of Medicine, Tufts University School of Medicine, Boston, Massachusetts 02111, USA.
Dinarello
C A
CA
D000328:Adult; D002478:Cells, Cultured; D003470:Culture Media / Q000494:pharmacology; D004357:Drug Synergism; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D007375:Interleukin-1 / Q000096:biosynthesis* / Q000235:genetics / Q000494:pharmacology; D016209:Interleukin-8 / Q000096:biosynthesis* / Q000235:genetics; D007963:Leukocytes, Mononuclear / Q000187:drug effects* / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008213:Lymphocyte Activation; D009997:Osmotic Pressure; D012462:Saline Solution, Hypertonic / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis* / Q000235:genetics
D003470:Culture Media; D007375:Interleukin-1; D016209:Interleukin-8; D008070:Lipopolysaccharides; D012462:Saline Solution, Hypertonic; D014409:Tumor Necrosis Factor-alpha