Cardiovascular Research Advance Access first published online on January 30, 2009
This version [Corrected Proof] published online on February 18, 2009
Cardiovascular Research, doi:10.1093/cvr/cvp040
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IL-10 attenuates TNF-
-induced NF
B pathway activation and cardiomyocyte apoptosis
1 Institute of Cardiovascular Sciences, St Boniface General Hospital Research Center, 351 Tache Avenue, Room R3022, Winnipeg, Manitoba, Canada R2H 2A6
2 Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada
3 Institute for Heart Research, Slovak Academy of Sciences, Bratislava, Slovak Republic
* Corresponding author. Tel: +1 204 235 3887; fax: +1 204 233 6723. E-mail address: psingal{at}sbrc.ca
Aims: We have recently reported that tumour necrosis factor-
(TNF-) 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- 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.
Methods and results: Cardiomyocytes isolated from adult Sprague–Dawley rats were exposed to TNF- (10 ng/mL), IL-10 (10 ng/mL), and IL-10+TNF- (ratio 1) for 4 h. Hydrogen peroxide and antioxidant trolox were used as positive controls. Exposure to TNF- 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- were associated with an increase in the inhibitor of 
B kinase (IKK) and nuclear factor kappa-B (NFB) phosphorylation. IL-10 by itself had no effect, but it prevented the above mentioned TNF--induced changes. Trolox also mitigated TNF- induced changes. Pre-exposure of cells to an IKK inhibitor (PS-1145) prevented TNF--induced caspase-3 and PARP cleavage. Inhibition of ERK 1/2 MAPK with PD98059 attenuated the protective role of IL-10 against TNF--induced activation of IKK and NFB as well as cardiomyocyte apoptosis.
Conclusion: The present study shows that TNF--induced activation of the NFB pathway plays a critical role in cardiomyocyte apoptosis. IL-10 prevents TNF--induced NFB activation and pro-apoptotic changes in cardiomyocytes by inhibiting IKK phosphorylation through the activation of ERK 1/2 MAPK.
KEYWORDS Signal transduction; Cell signalling; Oxidative stress; Cytokines
Time for primary review: 24 days