Protein kinase D activity controls endothelial nitric oxide synthesis

Area of Science:

• Endothelial cell biology
• Molecular signaling pathways
• Vascular physiology

Background:

• Vascular endothelial growth factor (VEGF) is vital for endothelial functions like angiogenesis and repair.
• Endothelial nitric oxide synthase (eNOS) activation is a key process regulated by VEGF.
• Protein kinase D (PKD) is activated in endothelial cells by VEGF.

Purpose of the Study:

• To investigate the role of PKD in VEGF-mediated eNOS activation.
• To elucidate the mechanism by which PKD influences endothelial cell function and vascular tone.

Main Methods:

• Mass spectrometry to identify eNOS phosphorylation sites by PKD.
• In vitro kinase assays using recombinant eNOS.
• Pharmacological inhibition and gene silencing of PKD in endothelial cells.
• In vivo studies monitoring carotid artery diameter in mice.

Main Results:

• PKD directly phosphorylates eNOS on Ser1179, leading to its activation and increased NO production.
• VEGF and phorbol ester treatment activate PKD and enhance eNOS Ser1179 phosphorylation.
• PKD inhibition or silencing impairs VEGF-induced endothelial cell migration.
• PKD inhibition in mice blocks VEGF-induced vasodilatation.

Conclusions:

• PKD is a novel kinase regulating eNOS activity in endothelial cells.
• The PKD-eNOS signaling axis is critical for endothelial cell migration and vascular tone.
• Targeting PKD may offer therapeutic strategies for vascular disorders.