Protein kinase C beta II upregulates intercellular adhesion molecule-1 via mitochondrial activation in cultured endothelial cells

Activation of protein kinase C (PKC) is closely linked with endothelial dysfunction. However, the effect of PKCβII on endothelial dysfunction has not been characterized in cultured endothelial cells. Here, using adenoviral PKCβII gene transfer and pharmacological inhibitors, the role of PKCβII on endothelial dysfucntion was investigated in cultured endothelial cells. Phorbol 12-myristate 13-acetate (PMA) increased reactive oxygen species (ROS), p66shc phosphorylation, intracellular adhesion molecule-1, and monocyte adhesion, which were inhibited by PKCβi (10 nM), a selective inhibitor of PKCβII. PMA increased the phosphorylation of CREB and manganese superoxide dismutase (MnSOD), which were also inhibited by PKCβi. Gene silencing of CREB inhibited PMA-induced MnSOD expression, suggesting that CREB plays a key role in MnSOD expression. Gene silencing of PKCβII inhibited PMA-induced mitochondrial ROS, MnSOD, and ICAM-1 expression. In contrast, overexpression of PKCβII using adenoviral PKCβII increased mitochondrial ROS, MnSOD, ICAM-1, and p66shc phosphorylation in cultured endothelial cells. Finally, PKCβII-induced ICAM-1 expression was inhibited by Mito-TEMPO, a mitochondrial ROS scavenger, suggesting the involvement of mitochondrial ROS in PKC-induced vascular inflammation. Taken together, the results suggest that PKCβII plays an important role in PMA-induced endothelial dysfunction, and that the inhibition of PKCβII-dependent p66shc signaling acts as a therapeutic target for vascular inflammatory diseases.

Trichostatin A Modulates Angiotensin II-induced Vasoconstriction and Blood Pressure Via Inhibition of p66shc Activation

Histone deacetylase (HDAC) has been recognized as a potentially useful therapeutic target for cardiovascular disorders. However, the effect of the HDAC inhibitor, trichostatin A (TSA), on vasoreactivity and hypertension remains unknown. We performed aortic coarctation at the inter-renal level in rats in order to create a hypertensive rat model. Hypertension induced by abdominal aortic coarctation was significantly suppressed by chronic treatment with TSA (0.5 mg/kg/day for 7 days). Nicotinamide adenine dinucleotide phosphate-driven reactive oxygen species production was also reduced in the aortas of TSA-treated aortic coarctation rats. The vasoconstriction induced by angiotensin II (Ang II, 100 nM) was inhibited by TSA in both endothelium-intact and endothelium-denuded rat aortas, suggesting that TSA has mainly acted in vascular smooth muscle cells (VSMCs). In cultured rat aortic VSMCs, Ang II increased p66shc phosphorylation, which was inhibited by the Ang II receptor type I (AT1R) inhibitor, valsartan (10 microM), but not by the AT2R inhibitor, PD123319. TSA (1~10 microM) inhibited Ang II-induced p66shc phosphorylation in VSMCs and in HEK293T cells expressing AT1R. Taken together, these results suggest that TSA treatment inhibited vasoconstriction and hypertension via inhibition of Ang II-induced phosphorylation of p66shc through AT1R.

APE1/Ref-1 as a Serological Biomarker for the Detection of Bladder Cancer / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Apurinic/apyrimidinic endonuclease 1/redox factor-1 (APE1/Ref-1) is a multifunctional protein that shows elevated expression in a number of cancers. We attempted to determine whether serum APE1/Ref-1 is elevated in patients with bladder cancer. MATERIALS AND METHODS: Serum APE1/Ref-1 levels were determined using enzyme-linked immunosorbent assay in serum from patients with bladder cancer who had not received chemotherapy or radiotherapy (n=51) and non-tumor controls (n=55). The area under the receiver operating characteristic area under the curve was applied to determine the correlation between clinical factors and the serum levels of APE1/Ref-1. RESULTS: Serum levels of APE1/Ref-1 in bladder cancer patients were significantly elevated compared to those of the control group (3.548+/-0.333 ng/100 muL [n=51] for bladder cancer vs. 1.547+/-0.319 ng/100 muL [n=55] for the control group), with a sensitivity and specificity of 93% and 59%, respectively. Serum APE1/Ref-1 levels are associated with tumor stage, grade, muscle invasion, and recurrence. CONCLUSION: Serum APE1/Ref-1 might be useful as a potential serologic biomarker for bladder cancer.

Acquired Long QT Syndrome Manifesting with Torsades de Pointes in a Patient with Panhypopituitarism due to Radiotherapy

We describe a 64-year-old male patient with panhypopituitarism who experienced polymorphic ventricular tachycardia (VT) associated with long QT intervals. The panhypopituitarism developed as a sequelae of radiation therapy administered 20 years prior to his current presentation and was recently aggravated by urinary tract infection with sepsis. In this case, polymorphic VT was resistant to conventional therapy (including magnesium infusion), and QT prolongation and T wave inversion were normalized after the administration of steroid and thyroid hormones. Thyroid hormone is generally known to be associated with torsades de pointes (TdP), but steroid or other hormones may also provoke TdP. Hormonal disorders should be considered as a cause of polymorphic VT with long QT intervals. Some arrhythmias can be life-threatening, and they can be prevented with supplementation of the insufficient hormone.

A standardized bamboo leaf extract inhibits monocyte adhesion to endothelial cells by modulating vascular cell adhesion protein-1

Bamboo leaves (Phyllostachys pubescens Mazel ex J. Houz (Poacea)) have a long history of food and medical applications in Asia, including Japan and Korea. They have been used as a traditional medicine for centuries. We investigated the mechanism of anti-inflammatory activity of a bamboo leaf extract (BLE) on tumor necrosis factor-alpha (TNF-alpha)-induced monocyte adhesion in human umbilical vein endothelial cells (HUVECs). Exposure of HUVECs to BLE did not inhibit cell viability or cause morphological changes at concentrations ranging from 1 microg/ml to 1 mg/ml. Treatment with 0.1 mg/ml BLE caused 63% inhibition of monocyte adhesion in TNF-alpha-activated HUVECs, which was associated with 38.4% suppression of vascular cell adhesion molecule-1 expression. Furthermore, TNF-alpha-induced reactive oxygen species generation was decreased to 47.9% in BLE treated TNF-alpha-activated HUVECs. BLE (0.05 mg/ml) also caused about 50% inhibition of interleukin-6 secretion from lipopolysaccharide-stimulated monocyte. The results indicate that BLE may be clinically useful as an anti-inflammatory or anti-oxidant for human cardiovascular disease including atherosclerosis.

Redox Regulating Protein APE1/Ref-1 Expression is Increased in Abdominal Aortic Coarctation-induced Hypertension Rats

BACKGROUND: Aim of study is designed to investigate whether apurinic/apyrimidinic endonuclease-1/redox factor-1 (APE1/Ref-1) expression is changed in abdominal aortic coarctation models. METHODS: Male Sprague-Dawley rats were randomly assigned with abdominal aortic coarctation, repaired group, sham, and control groups. Endothelial function was assessed with endothelium-dependent relaxations. Detection of superoxide anion and lipid peroxidation was performed by lucigenin chemiluminescence and thiobarbituric acid-reactive substances assay. APE1/Ref-1 expression was measured with Western blot and immunohistochemistry. RESULTS: In anesthetized condition, the abdominal aortic coarctation rats showed hypertension as systolic/diastolic arterial pressure of 171/114 mm Hg, compared with 114/94 mm Hg of control. Endothelium-dependent relaxations were significantly impaired in the aortic coarctation which was recovered in 1 week after coarctation repair. Superoxide production and lipid peroxidation were elevated in aortic coarctation rats. In immunohistochemistry, APE1/Ref-1 expressions were increased at aorta and kidney in aortic coarctation rats. Increased APE1/Ref-1 expression in aorta was recovered by repair of coarctation. CONCLUSIONS: Taken together, it suggests that APE1/Ref-1 expression was increased in aortic coarctation-induced hypertensive rats, suggesting a biomarker for hypertension. Impaired endothelium dependent relaxation in the aortic coarctation can be modulated by repair of coarctation or the modulation of blood pressure.

Vasorelaxing Activity of Ulmus davidiana Ethanol Extracts in Rats: Activation of Endothelial Nitric Oxide Synthase

Ulmus davidiana var. japonica Rehder (Urticales: Ulmaceae) (UD) is a tree widespread in northeast Asia. It is traditionally used for anticancer and anti-inflammatory therapy. The present study investigated the effect of an ethanol extract of UD on vascular tension and its underlying mechanism in rats. The dried root bark of UD was ground and extracted with 80% ethanol. The prepared UD extract was used in further analysis. The effect of UD on the cell viability, vasoreactivity and hemodynamics were investigated using propidium iodide staining in cultured cells, isometric tension recording and blood pressure analysis, respectively. Low dose of UD (10~100microg/ml) did not affect endothelial cell viability, but high dose of UD reduced cell viability. UD induced vasorelaxation in the range of 0.1~10microg/ml with an ED50 value of 2microg/ml. UD-induced vasorelaxation was completely abolished by removal of the endothelium or by pre-treatment with L-NAME, an inhibitor of nitric oxide synthase. UD inhibited calcium influx induced by phenylephrine and high K+ and also completely abolished the effect of L-NAME. Intravenous injection of UD extracts (10~100 mg/kg) decreased arterial and ventricular pressure in a dose-dependent manner. Moreover, UD extracts reduced the ventricular contractility (+dP/dt) in anesthetized rats. However, UD-induced hypotensive actions were minimized in L-NAME-treated rats. Taken together, out results showed that UD induced vasorelaxation and has antihypertensive properties, which may be due the activation of nitric oxide synthase in endothelium.

Redox Factor-1 Inhibits Cyclooxygenase-2 Expression via Inhibiting of p38 MAPK in the A549 Cells

In this study, we evaluated the role of apurinic/apyrimidinic endonuclease1/redox factor-1 (Ref-1) on the tumor necrosis factor-alpha (TNF-alpha) induced cyclooxygenase-2 (COX-2) expression using A549 lung adenocarcinoma cells. TNF-alpha induced the expression of COX-2 in A549 cells, but did not induce BEAS-2B expression. The expression of COX-2 in A549 cells was TNF-alpha dose-dependent (5~100 ng/ml). TNF-alpha-stimulated A549 cells evidenced increased Ref-1 expression in a dose-dependent manner. The adenoviral transfection of cells with AdRef-1 inhibited TNF-alpha-induced COX-2 expression relative to that seen in the control cells (Ad beta gal). Pretreatment with 10 micrometer of SB203580 suppressed TNF-alpha-induced COX-2 expression, thereby suggesting that p38 MAPK might be involved in COX-2 expression in A549 cells. The phosphorylation of p38 MAPK was increased significantly after 5 minutes of treatment with TNF-alpha, reaching a maximum level at 10 min which persisted for up to 60 min. However, p38MAPK phosphorylation was markedly suppressed in the Ref-1-overexpressed A549 cells. Taken together, our results appear to indicate that Ref-1 negatively regulates COX-2 expression in response to cytokine stimulation via the inhibition of p38 MAPK phosphorylation. In the lung cancer cell lines, Ref-1 may be involved as an important negative regulator of inflammatory gene expression.

Overexpression of Ref-1 Inhibits Lead-induced Endothelial Cell Death via the Upregulation of Catalase

The role of apurinic/apyrimidinic endonuclease1/redox factor-1 (Ref-1) on the lead (Pb)-induced cellular response was investigated in the cultured endothelial cells. Pb caused progressive cellular death in endothelial cells, which occurred in a concentration- and time-dependent manner. However, Ref-1 overexpression with AdRef-1 significantly inhibited Pb-induced cell death in the endothelial cells. Also the overexpression of Ref-1 significantly suppressed Pb-induced superoxide and hydrogen peroxide elevation in the endothelial cells. Pb exposure induced the downregulation of catalase, it was inhibited by the Ref-1 overexpression in the endothelial cells. Taken together, our data suggests that the overexpression of Ref-1 inhibited Pb-induced cell death via the upregulation of catalase in the cultured endothelial cells.