The nitrone spin trap 5,5-dimethyl-1-pyrroline N-oxide affects stress response and fate of lipopolysaccharide-primed RAW 264.7 macrophage cells.
The nitrone spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) is commonly used to study free radicals. Due to its free radical trapping properties, DMPO is thought to reduce free radial-mediated oxidative damage and other related cellular responses. The purpose of this study was to assess the effect of DMPO on lipopolysaccharide (LPS)-induced inflammation, endoplasmic reticulum (ER) stress, and apoptosis in RAW 264.7 cells. The results showed that DMPO at 50 mM inhibited inducible nitric oxide synthase expression when added shortly after LPS treatment (≤3 h). Interestingly, DMPO increased anti-inflammatory heme oxygenase-1 (HO-1) expression and reversed LPS-induced decrease in HO-1 expression. LPS could increase cellular ER stress as indicated by C/EBP homologous protein (CHOP) induction; DMPO reduced LPS effect on CHOP expression. Unexpectedly, DMPO had a synergistic effect with LPS on increased caspase-3 activity. Overall, DMPO harbors multiple modulating effects but may induce apoptosis in LPS-stressed cells when given at 50 mM, an effective dose for its anti-inflammatory activity in vitro. Our data provide clues for further understanding of the nitrone spin trap with therapeutic potential.
Department of Medicine, Section of Gastroenterology, The University of Chicago, Chicago, IL 60637, USA. zlzhai@yahoo.com
Zili
Z
Zhai
Sandra E
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Gomez-Mejiba
Dario C
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Ramirez
D048948:14-3-3 Proteins / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D002460:Cell Line; D003497:Cyclic N-Oxides / Q000494:pharmacology*; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism*; D005609:Free Radicals / Q000378:metabolism; D051547:Heme Oxygenase-1 / Q000096:biosynthesis / Q000187:drug effects; D007249:Inflammation / Q000139:chemically induced; D008070:Lipopolysaccharides; D008264:Macrophages / Q000276:immunology / Q000378:metabolism*; D008565:Membrane Proteins / Q000096:biosynthesis / Q000187:drug effects; D051379:Mice; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis / Q000187:drug effects; D009589:Nitrogen Oxides / Q000737:chemistry; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D013113:Spin Labels; D019097:Spin Trapping; D013312:Stress, Physiological; D051742:Transcription Factor CHOP / Q000096:biosynthesis / Q000187:drug effects
D048948:14-3-3 Proteins; D003497:Cyclic N-Oxides; C497250:Ddit3 protein, mouse; D005609:Free Radicals; D008070:Lipopolysaccharides; D008565:Membrane Proteins; D009589:Nitrogen Oxides; D019253:Proto-Oncogene Proteins c-bcl-2; D013113:Spin Labels; C015388:nitrones; D051742:Transcription Factor CHOP; C017245:5,5-dimethyl-1-pyrroline-1-oxide; D052247:Nitric Oxide Synthase Type II; D051547:Heme Oxygenase-1; C496542:Hmox1 protein, mouse; D053148:Caspase 3