Interleukin-1alpha stimulates proinflammatory cytokine expression in human cardiac myofibroblasts.
Cardiac myofibroblasts (CMF) play a key role in infarct repair and scar formation following myocardial infarction (MI) and are also an important source of proinflammatory cytokines. We postulated that interleukin-1alpha (IL-1alpha), a potential early trigger of acute inflammation post-MI, could stimulate human CMF to express additional proinflammatory cytokines. Furthermore, we hypothesized that these effects may be modulated by the anti-inflammatory cytokine interleukin-10 (IL-10). Human CMF were cultured from atrial biopsies from multiple patients. Interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and cardiotrophin-1 (CT-1) mRNA expression and secretion were measured using quantitative real-time RT-PCR and enzyme-linked immunosorbent assay. IL-1alpha (0.001-10 ng/ml, 0-6 h) stimulated IL-1beta, TNF-alpha, and IL-6 mRNA expression with distinct temporal and concentration profiles, resulting in increased cytokine secretion. The response to IL-1alpha was much greater than with TNF-alpha. Neither IL-1alpha nor TNF-alpha treatment modulated CT-1 mRNA expression. Immunoblotting with phosphospecific antibodies revealed that IL-1alpha stimulated the extracellular signal-regulated kinase (ERK)-1/2, p38 mitogen-activated protein kinase (MAPK), c-Jun NH(2)-terminal kinase (JNK), phosphatidylinositol 3-kinase (PI 3-kinase)/protein kinase B (Akt), and nuclear factor (NF)-kappaB signaling pathways. Pharmacological inhibitor studies indicated roles for PI 3-kinase/Akt and NF-kappaB pathways in mediating IL-1beta expression, and for NF-kappaB and p38 MAPK pathways in mediating TNF-alpha expression. IL-1alpha-induced IL-6 mRNA expression was reduced by p38 MAPK inhibition, but increased by ERK and JNK pathway inhibitors. IL-10 produced a consistent but modest reduction in IL-1alpha-induced IL-6 mRNA levels (not IL-1beta or TNF-alpha), but this was not reflected by reduced IL-6 protein secretion. In conclusion, IL-1alpha stimulates human CMF to express IL-1beta, TNF-alpha, and IL-6 via specific signaling pathways, responses that are unaffected by IL-10 exposure.
Turner
Neil A
NA
Division of Cardiovascular and Neuronal Remodelling, Leeds Institute of Genetics, Health, and Therapeutics, University of Leeds, Leeds LS2 9JT, United Kingdom. n.a.turner@leeds.ac.uk
Das
Anupam
A
Warburton
Philip
P
O'Regan
David J
DJ
Ball
Stephen G
SG
Porter
Karen E
KE
D002478:Cells, Cultured; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D006801:Humans; D016753:Interleukin-10 / Q000276:immunology / Q000494:pharmacology; D053582:Interleukin-1alpha / Q000276:immunology* / Q000378:metabolism / Q000494:pharmacology; D053583:Interleukin-1beta / Q000235:genetics / Q000378:metabolism; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000276:immunology; D009205:Myocarditis / Q000276:immunology*; D009206:Myocardium / Q000166:cytology / Q000276:immunology*; D016328:NF-kappa B / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism
C508609:IL10 protein, human; C508600:IL6 protein, human; D053582:Interleukin-1alpha; D053583:Interleukin-1beta; D015850:Interleukin-6; D016328:NF-kappa B; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases