Modulation of PKCδ signaling alters the shear stress-mediated increases in endothelial nitric oxide synthase transcription: Role of STAT3

Neetu Sud, Sanjiv Kumar, Stephen Wedgwood, Stephen Matthew Black

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

We have previously shown that the regulation of endothelial nitric oxide synthase (eNOS) in endothelial cells isolated from fetal lamb under static conditions is positively regulated by PKCδ. In this study, we explore the role of PKCδ in regulating shear-induced upregulation of eNOS. We found that shear caused a decrease in PKCδ activation. Modulation of PKCδ before shear with a dominant negative mutant of PKCδ (DN PKCδ) or bryostatin (a known PKCδ activator) demonstrated that PKCδ inhibition potentiates the shear-mediated increases in eNOS expression and activity, while PKCδ activation inhibited these events. To gain insight into the mechanism by which PKCδ inhibits shear-induced eNOS expression, we examined activation of STAT3, a known target for PKCδ phosphorylation. We found that shear decreased the phosphorylation of STAT3. Further the transfection of cells with DN PKCδ reduced, while PKCδ activation enhanced, STAT3 phosphorylation in the presence of shear. Transfection of cells with a dominant negative mutant of STAT3 enhanced eNOS promoter activity and nitric oxide production in response to shear. Finally, we found that mutating the STAT3 binding site sequence within the eNOS promoter increased promoter activity in response to shear and that this was no longer inhibited by bryostatin. In conclusion, shear decreases PKCδ activity and, subsequently, reduces STAT3 binding to the eNOS promoter. This signaling pathway plays a previously unidentified role in the regulation of eNOS expression by shear stress.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Volume296
Issue number3
DOIs
StatePublished - Mar 1 2009

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Nitric Oxide Synthase Type III
Bryostatins
Phosphorylation
Transfection
Nitric Oxide
Up-Regulation
Endothelial Cells
Binding Sites

Keywords

  • Biomechanical forces
  • Cell signaling
  • Endothelial cell
  • Phosphorylation

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology

Cite this

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title = "Modulation of PKCδ signaling alters the shear stress-mediated increases in endothelial nitric oxide synthase transcription: Role of STAT3",
abstract = "We have previously shown that the regulation of endothelial nitric oxide synthase (eNOS) in endothelial cells isolated from fetal lamb under static conditions is positively regulated by PKCδ. In this study, we explore the role of PKCδ in regulating shear-induced upregulation of eNOS. We found that shear caused a decrease in PKCδ activation. Modulation of PKCδ before shear with a dominant negative mutant of PKCδ (DN PKCδ) or bryostatin (a known PKCδ activator) demonstrated that PKCδ inhibition potentiates the shear-mediated increases in eNOS expression and activity, while PKCδ activation inhibited these events. To gain insight into the mechanism by which PKCδ inhibits shear-induced eNOS expression, we examined activation of STAT3, a known target for PKCδ phosphorylation. We found that shear decreased the phosphorylation of STAT3. Further the transfection of cells with DN PKCδ reduced, while PKCδ activation enhanced, STAT3 phosphorylation in the presence of shear. Transfection of cells with a dominant negative mutant of STAT3 enhanced eNOS promoter activity and nitric oxide production in response to shear. Finally, we found that mutating the STAT3 binding site sequence within the eNOS promoter increased promoter activity in response to shear and that this was no longer inhibited by bryostatin. In conclusion, shear decreases PKCδ activity and, subsequently, reduces STAT3 binding to the eNOS promoter. This signaling pathway plays a previously unidentified role in the regulation of eNOS expression by shear stress.",
keywords = "Biomechanical forces, Cell signaling, Endothelial cell, Phosphorylation",
author = "Neetu Sud and Sanjiv Kumar and Stephen Wedgwood and Black, {Stephen Matthew}",
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T1 - Modulation of PKCδ signaling alters the shear stress-mediated increases in endothelial nitric oxide synthase transcription

T2 - Role of STAT3

AU - Sud, Neetu

AU - Kumar, Sanjiv

AU - Wedgwood, Stephen

AU - Black, Stephen Matthew

PY - 2009/3/1

Y1 - 2009/3/1

N2 - We have previously shown that the regulation of endothelial nitric oxide synthase (eNOS) in endothelial cells isolated from fetal lamb under static conditions is positively regulated by PKCδ. In this study, we explore the role of PKCδ in regulating shear-induced upregulation of eNOS. We found that shear caused a decrease in PKCδ activation. Modulation of PKCδ before shear with a dominant negative mutant of PKCδ (DN PKCδ) or bryostatin (a known PKCδ activator) demonstrated that PKCδ inhibition potentiates the shear-mediated increases in eNOS expression and activity, while PKCδ activation inhibited these events. To gain insight into the mechanism by which PKCδ inhibits shear-induced eNOS expression, we examined activation of STAT3, a known target for PKCδ phosphorylation. We found that shear decreased the phosphorylation of STAT3. Further the transfection of cells with DN PKCδ reduced, while PKCδ activation enhanced, STAT3 phosphorylation in the presence of shear. Transfection of cells with a dominant negative mutant of STAT3 enhanced eNOS promoter activity and nitric oxide production in response to shear. Finally, we found that mutating the STAT3 binding site sequence within the eNOS promoter increased promoter activity in response to shear and that this was no longer inhibited by bryostatin. In conclusion, shear decreases PKCδ activity and, subsequently, reduces STAT3 binding to the eNOS promoter. This signaling pathway plays a previously unidentified role in the regulation of eNOS expression by shear stress.

AB - We have previously shown that the regulation of endothelial nitric oxide synthase (eNOS) in endothelial cells isolated from fetal lamb under static conditions is positively regulated by PKCδ. In this study, we explore the role of PKCδ in regulating shear-induced upregulation of eNOS. We found that shear caused a decrease in PKCδ activation. Modulation of PKCδ before shear with a dominant negative mutant of PKCδ (DN PKCδ) or bryostatin (a known PKCδ activator) demonstrated that PKCδ inhibition potentiates the shear-mediated increases in eNOS expression and activity, while PKCδ activation inhibited these events. To gain insight into the mechanism by which PKCδ inhibits shear-induced eNOS expression, we examined activation of STAT3, a known target for PKCδ phosphorylation. We found that shear decreased the phosphorylation of STAT3. Further the transfection of cells with DN PKCδ reduced, while PKCδ activation enhanced, STAT3 phosphorylation in the presence of shear. Transfection of cells with a dominant negative mutant of STAT3 enhanced eNOS promoter activity and nitric oxide production in response to shear. Finally, we found that mutating the STAT3 binding site sequence within the eNOS promoter increased promoter activity in response to shear and that this was no longer inhibited by bryostatin. In conclusion, shear decreases PKCδ activity and, subsequently, reduces STAT3 binding to the eNOS promoter. This signaling pathway plays a previously unidentified role in the regulation of eNOS expression by shear stress.

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