Selective Inhibitors of Kv11.1 Regulate IL-6 Expression by Macrophages in Response to TLR/IL-1R Ligands
The mechanism by which the platelet-endothelial cell adhesion molecule PECAM-1 regulates leukodiapedesis, vascular endothelial integrity, and proinflammatory cytokine expression in vivo is not known. We recently identified PECAM-1 as a negative regulator of Kv11.1, a specific voltage-gated potassium...
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doaj-8514cad6c1cf44c39b795c73f6f6edbe2020-11-25T02:19:31ZengHindawi LimitedThe Scientific World Journal1537-744X2010-01-01101580159610.1100/tsw.2010.155Selective Inhibitors of Kv11.1 Regulate IL-6 Expression by Macrophages in Response to TLR/IL-1R LigandsCheryl Hunter0Tejas B. Kadakia1Dianne Cooper2Mauro Perretti3Richard C. Schwartz4Simon B. Brown5MRC Centre for Inflammation Research, Queen's Medical Research Institute, College of Medicine and Veterinary Medicine, University of Edinburgh, UKDepartment of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USAWilliam Harvey Research Institute, Barts and The London School of Medicine, Queen Mary University of London, UKWilliam Harvey Research Institute, Barts and The London School of Medicine, Queen Mary University of London, UKDepartment of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USAMRC Centre for Inflammation Research, Queen's Medical Research Institute, College of Medicine and Veterinary Medicine, University of Edinburgh, UKThe mechanism by which the platelet-endothelial cell adhesion molecule PECAM-1 regulates leukodiapedesis, vascular endothelial integrity, and proinflammatory cytokine expression in vivo is not known. We recently identified PECAM-1 as a negative regulator of Kv11.1, a specific voltage-gated potassium channel that functioned in human macrophages to reset a resting membrane potential following depolarization. We demonstrate here that dofetilide (DOF), a selective inhibitor of the Kv11.1 current, had a profound inhibitory effect on neutrophil recruitment in mice following TLR/IL-1R–elicited peritonitis or intrascrotal injection of IL-1β, but had no effect on responses seen with TNFα. Furthermore, inhibitors of Kv11.1 (DOF, E4031, and astemizole), but not Kv1.3 (margatoxin), suppressed the expression of IL-6 and MCP-1 cytokines by murine resident peritoneal macrophages, while again having no effect on TNFα. In contrast, IL-6 expression by peritoneal mesothelial cells was unaffected. Using murine P388 cells, which lack endogenous C/EBPβexpression and are unresponsive to LPS for the expression of both IL-6 and MCP-1, we observed that DOF inhibited LPS-induced expression of IL-6 mRNA following ectopic expression of wild-type C/EBPβ, but not a serine-64 point mutant. Finally, DOF inhibited the constitutive activation of cdk2 in murine peritoneal macrophages; cdk2 is known to phosphorylate C/EBPβ at serine-64. Taken together, our results implicate a potential role for Kv11.1 in regulating cdk2 and C/EBPβ activity, where robust transactivation of both IL-6 and MCP-1 transcription is known to be dependent on serine-64 of C/EBPβ. Our data might also explain the altered phenotypes displayed by PECAM-1 knockout mice in several disease models.http://dx.doi.org/10.1100/tsw.2010.155 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Cheryl Hunter Tejas B. Kadakia Dianne Cooper Mauro Perretti Richard C. Schwartz Simon B. Brown |
spellingShingle |
Cheryl Hunter Tejas B. Kadakia Dianne Cooper Mauro Perretti Richard C. Schwartz Simon B. Brown Selective Inhibitors of Kv11.1 Regulate IL-6 Expression by Macrophages in Response to TLR/IL-1R Ligands The Scientific World Journal |
author_facet |
Cheryl Hunter Tejas B. Kadakia Dianne Cooper Mauro Perretti Richard C. Schwartz Simon B. Brown |
author_sort |
Cheryl Hunter |
title |
Selective Inhibitors of Kv11.1 Regulate IL-6 Expression by Macrophages in Response to TLR/IL-1R Ligands |
title_short |
Selective Inhibitors of Kv11.1 Regulate IL-6 Expression by Macrophages in Response to TLR/IL-1R Ligands |
title_full |
Selective Inhibitors of Kv11.1 Regulate IL-6 Expression by Macrophages in Response to TLR/IL-1R Ligands |
title_fullStr |
Selective Inhibitors of Kv11.1 Regulate IL-6 Expression by Macrophages in Response to TLR/IL-1R Ligands |
title_full_unstemmed |
Selective Inhibitors of Kv11.1 Regulate IL-6 Expression by Macrophages in Response to TLR/IL-1R Ligands |
title_sort |
selective inhibitors of kv11.1 regulate il-6 expression by macrophages in response to tlr/il-1r ligands |
publisher |
Hindawi Limited |
series |
The Scientific World Journal |
issn |
1537-744X |
publishDate |
2010-01-01 |
description |
The mechanism by which the platelet-endothelial cell adhesion molecule PECAM-1 regulates leukodiapedesis, vascular endothelial integrity, and proinflammatory cytokine expression in vivo is not known. We recently identified PECAM-1 as a negative regulator of Kv11.1, a specific voltage-gated potassium channel that functioned in human macrophages to reset a resting membrane potential following depolarization. We demonstrate here that dofetilide (DOF), a selective inhibitor of the Kv11.1 current, had a profound inhibitory effect on neutrophil recruitment in mice following TLR/IL-1R–elicited peritonitis or intrascrotal injection of IL-1β, but had no effect on responses seen with TNFα. Furthermore, inhibitors of Kv11.1 (DOF, E4031, and astemizole), but not Kv1.3 (margatoxin), suppressed the expression of IL-6 and MCP-1 cytokines by murine resident peritoneal macrophages, while again having no effect on TNFα. In contrast, IL-6 expression by peritoneal mesothelial cells was unaffected. Using murine P388 cells, which lack endogenous C/EBPβexpression and are unresponsive to LPS for the expression of both IL-6 and MCP-1, we observed that DOF inhibited LPS-induced expression of IL-6 mRNA following ectopic expression of wild-type C/EBPβ, but not a serine-64 point mutant. Finally, DOF inhibited the constitutive activation of cdk2 in murine peritoneal macrophages; cdk2 is known to phosphorylate C/EBPβ at serine-64. Taken together, our results implicate a potential role for Kv11.1 in regulating cdk2 and C/EBPβ activity, where robust transactivation of both IL-6 and MCP-1 transcription is known to be dependent on serine-64 of C/EBPβ. Our data might also explain the altered phenotypes displayed by PECAM-1 knockout mice in several disease models. |
url |
http://dx.doi.org/10.1100/tsw.2010.155 |
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