title: IL-10 attenuates TNF-alpha-induced NF kappaB pathway activation and cardiomyocyte apoptosis.
abstract: OBJECTIVE
  We have recently reported that tumour necrosis factor-alpha (TNF-alpha) increases oxidative stress and apoptosis in cardiomyocytes by upregulating p38 mitogen-activated protein (MAP) kinase (MAPK) phosphorylation. Interleukin-10 (IL-10) blocked these effects of TNF-alpha by upregulating extracellular signal-regulated kinase 1/2 (ERK 1/2) MAPK phosphorylation. However, the precise site of this IL-10 action is still unknown, and this is investigated in the present study.
  
  
  RESULTS
  Cardiomyocytes isolated from adult Sprague-Dawley rats were exposed to TNF-alpha (10 ng/mL), IL-10 (10 ng/mL), and IL-10+TNF-alpha (ratio 1) for 4 h. Hydrogen peroxide and antioxidant trolox were used as positive controls. Exposure to TNF-alpha resulted in an increase in the production of reactive oxygen species, the number of apoptotic cells, caspase-3 activation, and poly-ADP ribose polymerase (PARP) cleavage. Increased oxidative stress by using hydrogen peroxide also caused apoptosis. The changes due to TNF-alpha were associated with an increase in the inhibitor of kappaB kinase (IKK) and nuclear factor kappa-B (NF kappaB) phosphorylation. IL-10 by itself had no effect, but it prevented the above mentioned TNF-alpha-induced changes. Trolox also mitigated TNF-alpha induced changes. Pre-exposure of cells to an IKK inhibitor (PS-1145) prevented TNF-alpha-induced caspase-3 and PARP cleavage. Inhibition of ERK 1/2 MAPK with PD98059 attenuated the protective role of IL-10 against TNF-alpha-induced activation of IKK and NF kappaB as well as cardiomyocyte apoptosis.
  
  
  CONCLUSIONS
  The present study shows that TNF-alpha-induced activation of the NF kappaB pathway plays a critical role in cardiomyocyte apoptosis. IL-10 prevents TNF-alpha-induced NF kappaB activation and pro-apoptotic changes in cardiomyocytes by inhibiting IKK phosphorylation through the activation of ERK 1/2 MAPK.
authors.affiliation: Institute of Cardiovascular Sciences, St Boniface General Hospital Research Center, 351 Tache Avenue, Winnipeg, Manitoba, Canada.
authors.forename: Sanjiv
authors.initials: S
authors.lastname: Dhingra
authors.forename: Anita K
authors.initials: AK
authors.lastname: Sharma
authors.forename: Rakesh C
authors.initials: RC
authors.lastname: Arora
authors.forename: Jan
authors.initials: J
authors.lastname: Slezak
authors.forename: Pawan K
authors.initials: PK
authors.lastname: Singal
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism; D002478:Cells, Cultured; D002839:Chromans / Q000494:pharmacology; D004789:Enzyme Activation; D005419:Flavonoids / Q000494:pharmacology; D006575:Heterocyclic Compounds, 3-Ring / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D051550:I-kappa B Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism; D016753:Interleukin-10 / Q000378:metabolism*; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000201:enzymology / Q000276:immunology* / Q000473:pathology; D016328:NF-kappa B / Q000378:metabolism*; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress; D010766:Phosphorylation; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D002839:Chromans; D005419:Flavonoids; D006575:Heterocyclic Compounds, 3-Ring; D016328:NF-kappa B; D016877:Oxidants; C456319:PS1145; D047428:Protein Kinase Inhibitors; D011725:Pyridines; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D006861:Hydrogen Peroxide; D011065:Poly(ADP-ribose) Polymerases; D051550:I-kappa B Kinase; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; C505410:Casp3 protein, rat; D053148:Caspase 3; C010643:6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one