title: Effects of levo- and dextrosimendan on NF-kappaB-mediated transcription, iNOS expression and NO production in response to inflammatory stimuli.
abstract: OBJECTIVE
  Levosimendan is used in the treatment of decompensated heart failure. It increases the contractility of the myocardium by sensitizing troponin C to calcium. In addition, levosimendan has been reported to have beneficial effects in experimental models of septic shock. Because heart failure and sepsis have been associated with excessive nitric oxide (NO) production through inducible NOS (iNOS), we investigated the effects of the simendans on NO production and iNOS expression and on generation of pro-inflammatory cytokines.
  
  
  METHODS
  Macrophages and fibroblasts were exposed to inflammatory stimuli to induce iNOS expression. Proteins were measured by western blot and mRNA expression was determined by quantitative RT-PCR. Promoter activity and nuclear factor-kappaB (NF-kappaB) and the gamma-activated site (GAS; binding site for signal transducer and activator of transcription 1; STAT1)-mediated transcription were investigated using luciferase reporter constructs. Cytokines tumour necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) were measured by ELISA.
  
  
  RESULTS
  Levosimendan and dextrosimendan decreased NO production in a dose-dependent manner in cells exposed to inflammatory stimuli. The simendans decreased iNOS protein and mRNA expression but did not affect iNOS mRNA decay. These compounds decreased iNOS promoter activity and inhibited NF-kappaB-mediated transcription but not that mediated by STAT1/GAS. The simendans reduced IL-6 production slightly but they had no effect on TNF-alpha synthesis.
  
  
  CONCLUSIONS
  The simendans downregulated NF-kappaB-dependent transcription and decreased iNOS promoter activity, iNOS expression and NO production. These mechanisms may contribute to their beneficial clinical effects.
authors.affiliation: The Immunopharmacology Research Group, Medical School, University of Tampere and Research Unit, Tampere University Hospital, Tampere, Finland.
authors.forename: O
authors.initials: O
authors.lastname: Sareila
authors.forename: R
authors.initials: R
authors.lastname: Korhonen
authors.forename: H
authors.initials: H
authors.lastname: Auvinen
authors.forename: M
authors.initials: M
authors.lastname: Hämäläinen
authors.forename: H
authors.initials: H
authors.lastname: Kankaanranta
authors.forename: E
authors.initials: E
authors.lastname: Nissinen
authors.forename: E
authors.initials: E
authors.lastname: Moilanen
mesh_terms: D000818:Animals; D002460:Cell Line; D005347:Fibroblasts / Q000187:drug effects; D017930:Genes, Reporter; D006835:Hydrazones / Q000737:chemistry / Q000494:pharmacology*; D007249:Inflammation / Q000235:genetics / Q000378:metabolism*; D007739:L Cells; D008156:Luciferases / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects; D051379:Mice; D015394:Molecular Structure; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism*; D011724:Pyridazines / Q000737:chemistry / Q000494:pharmacology*; D000077464:Simendan; D014158:Transcription, Genetic / Q000187:drug effects*; D014162:Transfection
chemical_list: D006835:Hydrazones; D016328:NF-kappa B; D011724:Pyridazines; D009569:Nitric Oxide; D000077464:Simendan; D008156:Luciferases; D052247:Nitric Oxide Synthase Type II