scholarly journals Phytoestrogen Genistein Up-Regulates Endothelial Nitric Oxide Synthase Expression Via Activation of cAMP Response Element-Binding Protein in Human Aortic Endothelial Cells

Endocrinology ◽  
2012 ◽  
Vol 153 (7) ◽  
pp. 3190-3198 ◽  
Author(s):  
Hongwei Si ◽  
Jie Yu ◽  
Hongling Jiang ◽  
Hazel Lum ◽  
Dongmin Liu

We previously reported that genistein, a phytoestrogen, up-regulates endothelial nitric oxide synthase (eNOS) and prevents hypertension in rats that are independent of estrogen signaling machinery. However, how genistein regulates eNOS expression is unknown. In the present study, we show that genistein enhanced eNOS expression and NO synthesis in primary human aortic endothelial cells. Inhibition of extracellular signal regulated kinase, phosphoinositol-3 kinase, or protein kinase C did not affect genistein-enhanced eNOS expression and NO synthesis. However, chemical inhibition of protein kinase A (PKA) or adenoviral transfer of the specific endogenous PKA inhibitor gene completely abolished PKA activity and genistein-stimulated eNOS expression and NO production. Accordingly, genistein induced PKA activity and subsequent phosphorylation of cAMP response element (CRE)-binding protein (CREB) at Ser133. Suppression of CREB by small interfering RNA transfection abolished genistein-enhanced eNOS expression and NO production. Consistently, deletion of the CRE site within human eNOS promoter eliminated genistein-stimulated eNOS promoter activity. These findings provide the first evidence to our knowledge that genistein may play a beneficial role in vascular function through targeting the PKA/CREB/eNOS/NO signaling pathway.

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Xu-Ping Wang ◽  
Zhen-Ying Cheng ◽  
Katrina L. Schmid

GABABreceptors regulate the intracellular Ca2+concentration ([Ca2+]i) in a number of cells (e.g., retina, airway epithelium and smooth muscle), but whether they are expressed in vascular endothelial cells and similarly regulate the [Ca2+]iis not known. The purpose of this study was to investigate the expression of GABABreceptors, a subclass of receptors to the inhibitory neurotransmitterγ-aminobutyric acid (GABA), in cultured human aortic endothelial cells (HAECs), and to explore if altering receptor activation modified [Ca2+]iand endothelial nitric oxide synthase (eNOS) translocation. Real-time PCR, western blots and immunofluorescence were used to determine the expression of GABAB1and GABAB2in cultured HAECs. The effects of GABABreceptors on [Ca2+]iin cultured HAECs were demonstrated using fluo-3. The influence of GABABreceptors on eNOS translocation was assessed by immunocytochemistry. Both GABAB1and GABAB2mRNA and protein were expressed in cultured HAECs, and the GABAB1and GABAB2proteins were colocated in the cell membrane and cytoplasm. One hundredμM baclofen caused a transient increase of [Ca2+]iand eNOS translocation in cultured HAECs, and the effects were attenuated by pretreatment with the selective GABABreceptor antagonists CGP46381 and CGP55845. GABABreceptors are expressed in HAECs and regulate the [Ca2+]iand eNOS translocation. Cultures of HAECs may be a usefulin vitromodel for the study of GABABreceptors and vascular biology.


2002 ◽  
Vol 22 (24) ◽  
pp. 8467-8477 ◽  
Author(s):  
Xiu-Fen Ming ◽  
Hema Viswambharan ◽  
Christine Barandier ◽  
Jean Ruffieux ◽  
Kozo Kaibuchi ◽  
...  

ABSTRACT Endothelial nitric oxide synthase (eNOS) is an important regulator of cardiovascular homeostasis by production of nitric oxide (NO) from vascular endothelial cells. It can be activated by protein kinase B (PKB)/Akt via phosphorylation at Ser-1177. We are interested in the role of Rho GTPase/Rho kinase (ROCK) pathway in regulation of eNOS expression and activation. Using adenovirus-mediated gene transfer in human umbilical vein endothelial cells (HUVECs), we show here that both active RhoA and ROCK not only downregulate eNOS gene expression as reported previously but also inhibit eNOS phosphorylation at Ser-1177 and cellular NO production with concomitant suppression of PKB activation. Moreover, coexpression of a constitutive active form of PKB restores the phosphorylation but not gene expression of eNOS in the presence of active RhoA. Furthermore, we show that thrombin inhibits eNOS phosphorylation, as well as expression via Rho/ROCK pathway. Expression of the active PKB reverses eNOS phosphorylation but has no effect on downregulation of eNOS expression induced by thrombin. Taken together, these data demonstrate that Rho/ROCK pathway negatively regulates eNOS phosphorylation through inhibition of PKB, whereas it downregulates eNOS expression independent of PKB.


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