Platelet-Endothelial Cell Adhesion Molecule-1 Regulates Endothelial NO Synthase Activity and Localization Through Signal Transducers and Activators of Transcription 3-Dependent NOSTRIN Expression

Background-NO produced by the endothelial NO synthase (eNOS) is an important regulator of cardiovascular physiological and pathological features. eNOS is activated by numerous stimuli, and its activity is tightly regulated. Platelet-endothelial cell adhesion molecule-1 (PECAM-1) has been implicated in regulating eNOS activity in response to shear stress. The current study was conducted to determine the role of PECAM-1 in the regulation of basal eNOS activity. Methods and Results-We demonstrate that PECAM-1-knockout ECs have increased basal eNOS activity and NO production. Mechanistically, increased eNOS activity is associated with a decrease in the inhibitory interaction of eNOS with caveolin-1, impaired subcellular localization of eNOS, and decreased eNOS traffic inducer (NOSTRIN) expression in the absence of PECAM-1. Furthermore, we demonstrate that activation of blunted signal transducers and activators of transcription 3 (STAT3) in the absence of PECAM-1 results in decreased NOSTRIN expression via direct binding of the signal transducers and activators of transcription 3 to the NOSTRIN promoter. Conclusion-Our results reveal an elegant mechanism of eNOS regulation by PECAM-1 through signal transducers and activators of transcription 3-mediated transcriptional control of NOSTRIN. (Arterioscler Thromb Vasc Biol. 2011;31:643-649.)