APE1/Ref-1 Inhibits Adipogenic Transcription Factors during Adipocyte Differentiation in 3T3-L1 Cells.

Apurinic/apyrimidinic endonuclease 1/redox factor-1 (APE1/Ref-1) is a multifunctional protein involved in DNA repair and redox regulation. The redox activity of APE1/Ref-1 is involved in inflammatory responses and regulation of DNA binding of transcription factors related to cell survival pathways. However, the effect of APE1/Ref-1 on adipogenic transcription factor regulation remains unknown. In this study, we investigated the effect of APE1/Ref-1 on the regulation of adipocyte differentiation in 3T3-L1 cells. During adipocyte differentiation, APE1/Ref-1 expression significantly decreased with the increased expression of adipogenic transcription factors such as CCAAT/enhancer binding protein (C/EBP)-α and peroxisome proliferator-activated receptor (PPAR)-γ, and the adipocyte differentiation marker adipocyte protein 2 (aP2) in a time-dependent manner. However, APE1/Ref-1 overexpression inhibited C/EBP-α, PPAR-γ, and aP2 expression, which was upregulated during adipocyte differentiation. In contrast, silencing APE1/Ref-1 or redox inhibition of APE1/Ref-1 using E3330 increased the mRNA and protein levels of C/EBP-α, PPAR-γ, and aP2 during adipocyte differentiation. These results suggest that APE1/Ref-1 inhibits adipocyte differentiation by regulating adipogenic transcription factors, suggesting that APE1/Ref-1 is a potential therapeutic target for regulating adipocyte differentiation.

ATP Binding Cassette Transporter A1 is Involved in Extracellular Secretion of Acetylated APE1/Ref-1.

Acetylation of nuclear apurinic/apyrimidinic endonuclease-1/redox factor-1 (APE1/Ref-1) is associated with its extracellular secretion, despite the lack of an N-terminal protein secretion signal. In this study, we investigated plasma membrane targeting and translocation of APE1/Ref-1 in HEK293T cells with enhanced acetylation. While APE1/Ref-1 targeting was not affected by inhibition of the endoplasmic reticulum/Golgi-dependent secretion, its secretion was reduced by inhibitors of ATP-binding cassette (ABC) transporters, and siRNA-mediated down-regulation of ABC transporter A1. The association between APE1/Ref-1 and ABCA1 transporter was confirmed by proximal ligation assay and immunoprecipitation experiments. An APE1/Ref-1 construct with mutated acetylation sites (K6/K7R) showed reduced co-localization with ABC transporter A1. Exposure of trichostatin A (TSA) induced the acetylation of APE1/Ref-1, which translocated into membrane fraction. Taken together, acetylation of APE1/Ref-1 is considered to be necessary for its extracellular targeting via non-classical secretory pathway using the ABCA1 transporter.

Anthocyanin-Rich Extract from Red Chinese Cabbage Alleviates Vascular Inflammation in Endothelial Cells and Apo E-/- Mice.

Anthocyanins, the most prevalent flavonoids in red/purple fruits and vegetables, are known to improve immune responses and reduce chronic disease risks. In this study, the anti-inflammatory activities of an anthocyanin-rich extract from red Chinese cabbage (ArCC) were shown based on its inhibitory effects in cultured endothelial cells and hyperlipidemic apolipoprotein E-deficient mice. ArCC treatment suppressed monocyte adhesion to tumor necrosis factor-α-stimulated endothelial cells. This was validated by ArCC's ability to downregulate the expression and transcription of endothelial adhesion molecules, determined by immunoblot and luciferase promoter assays, respectively. The regulation of adhesion molecules was accompanied by transcriptional inhibition of nuclear factor-κB, which restricted cytoplasmic localization as shown by immunocytochemistry. Administration of ArCC (150 or 300 mg/kg/day) inhibited aortic inflammation in hyperlipidemic apolipoprotein E-deficient mice, as shown by in vivo imaging. Immunohistochemistry and plasma analysis showed that the aortas from these mice exhibited markedly lower leukocyte infiltration, reduced plaque formation, and lower concentrations of blood inflammatory cytokines than those observed in the control mice. The results suggest that the consumption of anthocyanin-rich red Chinese cabbage is closely correlated with lowering the risk of vascular inflammatory diseases.

APE1/Ref-1 Inhibits Phosphate-Induced Calcification and Osteoblastic Phenotype Changes in Vascular Smooth Muscle Cells.

Vascular calcification plays a role in the pathogenesis of atherosclerosis, diabetes, and chronic kidney disease; however, the role of apurinic/apyrimidinic endonuclease 1/redox factor-1 (APE1/Ref-1) in inorganic phosphate (Pi)-induced vascular smooth muscle cell (VSMC) calcification remains unknown. In this study, we investigated the possible role of APE1/Ref-1 in Pi-induced VSMC calcification. We observed that Pi decreased endogenous APE1/Ref-1 expression and promoter activity in VSMCs, and that adenoviral overexpression of APE1/Ref-1 inhibited Pi-induced calcification in VSMCs and in an ex vivo organ culture of a rat aorta. However, a redox mutant of APE1/Ref-1(C65A/C93A) did not reduce Pi-induced calcification in VSMCs, suggesting APE1/Ref-1-mediated redox function against vascular calcification. Additionally, APE1/Ref-1 overexpression inhibited Pi-induced intracellular and mitochondrial reactive oxygen species production, and APE1/Ref-1 overexpression resulted in decreased Pi-induced lactate dehydrogenase activity, pro-apoptotic Bax levels, and increased anti-apoptotic Bcl-2 protein levels. Furthermore, APE1/Ref-1 inhibited Pi-induced osteoblastic differentiation associated with alkaline phosphatase activity and inhibited Pi-exposure-induced loss of the smooth muscle phenotype. Our findings provided valuable insights into the redox function of APE1/Ref-1 in preventing Pi-induced VSMC calcification by inhibiting oxidative stress and osteoblastic differentiation, resulting in prevention of altered osteoblastic phenotypes in VSMCs.

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 PKCßII on endothelial dysfunction has not been characterized in cultured endothelial cells. Here, using adenoviral PKCßII gene transfer and pharmacological inhibitors, the role of PKCßII 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 PKCßi (10 nM), a selective inhibitor of PKCßII. PMA increased the phosphorylation of CREB and manganese superoxide dismutase (MnSOD), which were also inhibited by PKCßi. Gene silencing of CREB inhibited PMA-induced MnSOD expression, suggesting that CREB plays a key role in MnSOD expression. Gene silencing of PKCßII inhibited PMA-induced mitochondrial ROS, MnSOD, and ICAM-1 expression. In contrast, overexpression of PKCßII using adenoviral PKCßII increased mitochondrial ROS, MnSOD, ICAM-1, and p66shc phosphorylation in cultured endothelial cells. Finally, PKCßII-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 PKCßII plays an important role in PMA-induced endothelial dysfunction, and that the inhibition of PKCßII-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 µM), but not by the AT2R inhibitor, PD123319. TSA (1~10 µM) 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.

Heterozygous Apex1 deficiency exacerbates lipopolysaccharide-induced systemic inflammation in a murine model.

The biological role of apurinic/apyrimidinic endonuclease 1/redox factor-1 (Apex1) in modulating systemic inflammation remains unclear. This study aimed to assess the impact of Apex1 deficiency on systemic inflammation triggered by lipopolysaccharide (LPS) in a murine model. The methods involved transcriptomic analysis and assessments of inflammatory responses in age-matched 8-week-old Apex1+/- and wild-type Apex1+/+ mice, generated using the CRISPR/Cas9 system. Apex1+/- mice displayed no overt changes in body weight, however, Apex1 protein expressions in tissues were significantly reduced compared to wild-type mice. Furthermore, in Apex1+/- mice transcriptomic analysis showed that genes associated with antioxidant pathways were downregulated, and levels of superoxide production, 8-hydroxy-2'-deoxyguanosine (8-OHdG), and malondialdehyde (MDA) were increased. Moreover, hematological analysis showed increased neutrophil levels and a twofold increase in the count of splenic lymphocyte antigen 6 family member G+ (Ly6G+) neutrophils in the Apex1+/- mice compared to those in Apex1+/+ mice. Furthermore, following LPS treatment, the levels of cytokines and chemokines, including interleukin-1ß, interleukin-10, tumor necrosis factor-α, and monocyte chemoattractant protein 1, increased in the Apex1+/- mice. The Kaplan-Meier curve showed a significant reduction in the survival rates of Apex1+/- mice treated with LPS compared to those of Apex1+/+ mice. The hepatic and lung injury scores and Ly6G+ neutrophil infiltration levels also increased in Apex1+/- mice after LPS treatment. These results showed that Apex1 deficiency exacerbated the LPS-induced tissue damage in the lung and liver. These findings illustrate that in vivo Apex1 deficiency exacerbates LPS-induced systemic inflammation, tissue damage, and mortality in a murine model, highlighting the crucial role of Apex1 in mitigating inflammatory responses and maintaining a holistic physiological equilibrium.

Identification of plasma APE1/Ref-1 in lipopolysaccharide-induced endotoxemic rats: implication of serological biomarker for an endotoxemia.

Apurinic/apyrimidinic endonuclease1/Redox factor-1 (APE1/Ref-1) is a multifunctional protein involved in base excision DNA repair and in transcriptional regulation of gene expression. We investigated whether APE1/Ref-1 increased in plasma of endotoxemic rats. Lipopolysaccharide (LPS) was used to induce endotoxemia in rats. Administration of LPS (10 mg/kg, i.p.) significantly induced plasma nitrite production and tumor necrosis factor-α (TNF-α). A 37 kDa immunoreactive band was detected in cell-free plasma of LPS-treated rats using anti-APE1/Ref-1, which reached a maximum at 12 h after the LPS injection. The 37 kDa immunoreactive band was identified as rat APE1/Ref-1 by liquid chromatography/tandem mass spectrometry. Interestingly, treatment with recombinant human APE1/Ref-1 protein (2-5 µg/ml for 18 h) inhibited TNF-α-induced vascular cell adhesion molecule-1 expression in human umbilical vein endothelial cells. Taken together, the level of plasma APE1/Ref-1 increased in LPS-induced endotoxemic rats, suggesting that plasma APE1/Ref-1 might serve as a serological biomarker for endotoxemia.

Histone deacetylases inhibitor trichostatin A modulates the extracellular release of APE1/Ref-1.

Apurinic/apyrimidinic endonuclease 1/Redox factor-1 (APE1/Ref-1) can be acetylated via post-translational modification. We investigated the effect of an inhibitor of histone deacetylases on the extracellular release of APE1/Ref-1 in HEK293 cells. Trichostatin A (TSA), an inhibitor of histone deacetylases, induced APE1/Ref-1 secretion without changing cell viability. In a fluorescence quantitative assay, the secreted APE1/Ref-1 was estimated to be about 10 ng/mL in response to TSA (1 µM). However, TSA did not induce the secretion of lysine-mutated APE1/Ref-1 (K6R/K7R). TSA also caused nuclear to cytoplasmic translocation of APE1/Ref-1. Taken together, these findings suggest that APE1/Ref-1 is a protein whose secretion is governed by lysine acetylation.

Capsanthin Inhibits Atherosclerotic Plaque Formation and Vascular Inflammation in ApoE-/- Mice.

Capsanthin is a red pigment and the major carotenoid component of red paprika (Capsicum annuum L.). However, its role in atherosclerosis is yet to be fully elucidated. This study investigated the role of dietary capsanthin in vascular inflammation in atherosclerotic mice. We evaluated the anti-atherosclerotic effects of daily oral administration of capsanthin (0.5 mg/kg of body weight/day) in apolipoprotein E-deficient (ApoE-/-) mice fed a Western-type diet (WD). Capsanthin treatment inhibited vascular cell adhesion molecule 1 expression and nuclear factor-κB ser536 phosphorylation in tumor necrosis factor-α-stimulated cultured endothelial cells. Dietary capsanthin significantly inhibited the WD-induced elevation in the plasma levels of total cholesterol, low-density lipoprotein cholesterol (LDL-C), and triglyceride in mice. Interestingly, capsanthin reduced aortic plaque formation and VCAM-1 expression, which is vascular inflammation, in atherosclerotic mice. In addition, the neutrophil-lymphocyte ratio, a systemic inflammatory marker, was inhibited in capsanthin-treated mice. Furthermore, capsanthin significantly reduced the levels of proinflammatory cytokines, such as TNF-α, interleukin-6, and monocyte chemoattractant protein-1, in the plasma of atherosclerotic mice. Collectively, our data demonstrate that dietary capsanthin plays a protective role against atherosclerosis in hyperlipidemic mice. This protective effect could be attributed to the anti-inflammatory properties of capsanthin.

Human HOXA5 homeodomain enhances protein transduction and its application to vascular inflammation.

Cellular protein delivery is an emerging technique by which exogenous recombinant proteins are delivered into mammalian cells across the membrane. We have developed an Escherichia coli expression vector including human specific gene sequences for protein cellular delivery. The plasmid was generated by ligation the nucleotides 770-817 of the homeobox A5 mRNA sequence which was matched with protein transduction domain (PTD) of homeodomain protein A5 (HOXA5) into pET expression vector. The cellular uptake of HOXA5-PTD-EGFP was detected in 1min and its transduction reached a maximum at 1h within cell lysates. The cellular uptake of HOXA5-EGFP at 37°C was greater than in 4°C. For study for the functional role of human HOXA5-PTD, we purified HOXA5-APE1/Ref-1 and applied it on monocyte adhesion. Pretreatment with HOXA5-APE1/Ref-1 (100nM) inhibited TNF-α-induced monocyte adhesion to endothelial cells, compared with HOXA5-EGFP. Taken together, our data suggested that human HOXA5-PTD vector provides a powerful research tools for uncovering cellular functions of proteins or for the generation of human PTD-containing proteins.

17ß-Estradiol Increases APE1/Ref-1 Secretion in Vascular Endothelial Cells and Ovariectomized Mice: Involvement of Calcium-Dependent Exosome Pathway.

Apurinic/apyrimidinic endonuclease-1/redox factor-1 (APE1/Ref-1) is a multifunctional protein that can be secreted, and recently suggested as new biomarker for vascular inflammation. However, the endogenous hormones for APE1/Ref-1 secretion and its underlying mechanisms are not defined. Here, the effect of twelve endogenous hormones on APE1/Ref-1 secretion was screened in cultured vascular endothelial cells. The endogenous hormones that significantly increased APE1/Ref-1 secretion was 17ß-estradiol (E2), 5?-dihydrotestosterone, progesterone, insulin, and insulin-like growth factor. The most potent hormone inducing APE1/Ref-1 secretion was E2, which in cultured endothelial cells, E2 for 24 h increased APE1/Ref-1 secretion level of 4.56 ± 1.16 ng/mL, compared to a basal secretion level of 0.09 ± 0.02 ng/mL. Among the estrogens, only E2 increased APE1/Ref-1 secretion, not estrone and estriol. Blood APE1/Ref-1 concentrations decreased in ovariectomized (OVX) mice but were significantly increased by the replacement of E2 (0.39 ± 0.09 ng/mL for OVX vs. 4.67 ± 0.53 ng/mL for OVX + E2). E2-induced APE1/Ref-1secretion was remarkably suppressed by the estrogen receptor (ER) blocker fulvestrant and intracellular Ca2+ chelator 1,2-Bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis (acetoxymethyl ester) (BAPTA-AM), suggesting E2-induced APE1/Ref-1 secretion was dependent on ER and intracellular calcium. E2-induced APE1/Ref-1 secretion was significantly inhibited by exosome inhibitor GW4869. Furthermore, APE1/Ref-1 level in CD63-positive exosome were increased by E2. Finally, fluorescence imaging data showed that APE1/Ref-1 co-localized with CD63-labled exosome in the cytoplasm of cells upon E2 treatment. Taken together, E2 was the most potent hormone for APE1/Ref-1 secretion, which appeared to occur through exosomes that were dependent on ER and intracellular Ca2+. Furthermore, hormonal effects should be considered when analyzing biomarkers for vascular inflammation.

Protective Role of Dietary Capsanthin in a Mouse Model of Nonalcoholic Fatty Liver Disease.

Capsanthin is the main carotenoid compound in red paprika (Capsicum annuum L.). However, little is known about the beneficial effects of capsanthin in nonalcoholic fatty liver disease (NAFLD). In this study, the hepatoprotective activity of capsanthin was investigated in a mouse model of NAFLD. Apolipoprotein-E knockout mice were fed with normal diet, Western-type diet (WD, NAFLD model), WD with capsanthin (0.5 mg/kg of body weight/day, CAP), WD with capsanthin-rich extract (25 mg/kg of body weight/day; CRE), or WD with red paprika powder (25 mg/kg of body weight/day, RPP) for 12 weeks. The carotenoid content in CRE or RPP was analyzed using ultraperformance liquid chromatography. The capsanthin concentration in CRE was 2067 mg/100 g of dry weight, which was 63% of total carotenoids. The oral administration of CRE or capsanthin significantly reduced the WD-induced increase in body weight and lipid accumulation in the liver (vs. the RPP group). In addition, CRE or capsanthin significantly inhibited the WD-induced increase in cholesterol and low-density lipoprotein levels. Furthermore, CRE or capsanthin showed reduced levels of plasma alanine and aspartate aminotransferase (ALT and AST, respectively), suggesting a steatohepatitis protective effect. Capsanthin regulated mRNA levels of peroxisome proliferator-activated receptor alpha (Pparα), carnitine palmitoyltransferase 1A (Cpt1a), acyl-CoA oxidase 1 (Acox1), and sterol regulatory element binding protein-1c (Srebp1c), which are associated with hepatic fatty acid metabolism. Overall, our results suggest that the capsanthin of red paprika plays a protective role against hepatic steatosis/steatohepatitis in NAFLD.

Elevated APE1/Ref-1 Levels of Synovial Fluids in Patients with Rheumatoid Arthritis: Reflection of Disease Activity.

There is growing evidence that apurinic/apyrimidinic endonuclease 1/redox factor-1 (APE1/Ref-1) regulates inflammatory responses. Rheumatoid arthritis (RA) is an autoimmune disease, which is characterized with synovitis and joint destruction. Therefore, this study was planned to investigate the relationship between APE1/Ref-1 and RA. Serum and synovial fluid (SF) were collected from 46 patients with RA, 45 patients with osteoarthritis (OA), and 30 healthy control (HC) patients. The concentration of APE1/Ref-1 in serum or SF was measured using the sandwich enzyme-linked immunosorbent assay (ELISA). The disease activity in RA patients was measured using the 28-joint disease activity score (DAS28). The serum APE1/Ref-1 levels in RA patients were significantly increased compared to HC and OA patients (0.44 ± 0.39 ng/mL for RA group vs. 0.19 ± 0.14 ng/mL for HC group, p < 0.05 and vs. 0.19 ± 0.11 ng/mL for OA group, p < 0.05). Likewise, the APE1/Ref-1 levels of SF in RA patients were also significantly increased compared to OA patients (0.68 ± 0.30 ng/mL for RA group vs. 0.31 ± 0.12 ng/mL for OA group, p < 0.001). The APE1/Ref-1 concentration in SF of RA patients was positively correlated with DAS28. Thus, APE1/Ref-1 may reflect the joint inflammation and be associated with disease activity in RA.

The Biological Role of Apurinic/Apyrimidinic Endonuclease1/Redox Factor-1 as a Therapeutic Target for Vascular Inflammation and as a Serologic Biomarker.

Endothelial dysfunction promotes vascular inflammation by inducing the production of reactive oxygen species and adhesion molecules. Vascular inflammation plays a key role in the pathogenesis of vascular diseases and atherosclerotic disorders. However, whether there is an endogenous system that can participate in circulating immune surveillance or managing a balance in homeostasis is unclear. Apurinic/apyrimidinic endonuclease 1/redox factor-1 (henceforth referred to as APE1/Ref-1) is a multifunctional protein that can be secreted from cells. It functions as an apurinic/apyrimidinic endonuclease in the DNA base repair pathway and modulates redox status and several types of transcriptional factors, in addition to its anti-inflammatory activity. Recently, it was reported that the secretion of APE1/Ref-1 into the extracellular medium of cultured cells or its presence in the plasma can act as a serological biomarker for certain disorders. In this review, we summarize the possible biological functions of APE1/Ref-1 according to its subcellular localization or its extracellular secretions, as therapeutic targets for vascular inflammation and as a serologic biomarker.

Mosapride Improves Lower Esophageal Sphincter and Esophageal Body Function in Patients With Minor Disorders of Esophageal Peristalsis.

BACKGROUND/AIMS: High-resolution manometry (HRM) has broadened the awareness of minor esophageal peristaltic disorders. However, the treatments for these minor disorders are limited and the role of prokinetics has been controversial. This study evaluates the effect of mosapride in patients with minor peristaltic disorders. METHODS: This study prospectively enrolled 21 patients with esophageal symptoms who were diagnosed with minor peristaltic disorders by gastroscopy and HRM using the Chicago classification version 3.0. Patients received mosapride 30 mg daily for 2 weeks. Symptoms were assessed using the abbreviated World Health Organization quality of life scale (WHOQOL-BREF) and a HRM study was performed before and after 2 weeks of treatment. RESULTS: HRM metrics of lower esophageal sphincter (LES) respiratory mean pressure (median 14.6 mmHg vs 17.3 mmHg; interquartile range [IQR] 8.7-22.5 mmHg vs 12.5-25.9 mmHg; P = 0.004) and distal contractile integral (median 343.8 mmHg·sec·cm vs 698.1 mmHg·sec·cm; IQR 286.5-795.9 mmHg·sec·cm vs 361.0-1127.6 mmHg·sec·cm; P = 0.048) were significantly increased after treatment. Complete response (≥ 80.0%), satisfactory response (≥ 50.0%), partial response (< 50.0%), and refractory response rates were 19.0%, 52.4%, 14.3%, and 14.3%, respectively. However, there was no statistical difference in all WHOQOL-BREF scores before and after treatment. Univariate analysis showed LES respiratory mean pressure (P = 0.036) was associated with symptom improvement (complete + satisfactory group). However, no statistical difference was found in other factors after multivariate analysis. CONCLUSIONS: Mosapride improved esophageal symptoms and significantly increased LES respiratory mean pressure and distal contractile integral. Therefore, mosapride could enhance LES and esophageal body contraction pressures in patients with minor peristaltic disorders.

Plasma APE1/Ref-1 Correlates with Atherosclerotic Inflammation in ApoE-/- Mice.

Apurinic/apyrimidinic endonuclease 1/redox factor-1 (APE1/Ref-1) is involved in DNA base repair and reducing activity. However, the role of APE1/Ref-1 in atherosclerosis is unclear. Herein, we investigated the role of APE1/Ref-1 in atherosclerotic apolipoprotein E (ApoE-/-) mice fed with a Western-type diet. We found that serologic APE1/Ref-1 was strongly correlated with vascular inflammation in these mice. Neutrophil/lymphocyte ratio (NLR), endothelial cell/macrophage activation, and atherosclerotic plaque formation, reflected by atherosclerotic inflammation, were increased in the ApoE-/- mice fed with a Western-type diet. APE1/Ref-1 expression was upregulated in aortic tissues of these mice, and was co-localized with cells positive for cluster of differentiation 31 (CD31) and galectin-3, suggesting endothelial cell/macrophage expression of APE1/Ref-1. Interestingly, APE1/Ref-1 plasma levels of ApoE-/- mice fed with a Western-type diet were significantly increased compared with those of the mice fed with normal diet (15.76 ± 3.19 ng/mL vs. 3.51 ± 0.50 ng/mL, p < 0.05), and were suppressed by atorvastatin administration. Correlation analysis showed high correlation between plasma APE1/Ref-1 levels and NLR, a marker of systemic inflammation. The cut-off value for APE1/Ref-1 for predicting atherosclerotic inflammation at 4.903 ng/mL showed sensitivity of 100% and specificity of 91%. We conclude that APE1/Ref-1 expression is upregulated in aortic endothelial cells/macrophages of atherosclerotic mice, and that plasma APE1/Ref-1 levels could predict atherosclerotic inflammation.

Endothelial nitric oxide synthase activation contributes to post-exercise hypotension in spontaneously hypertensive rats.

We investigated the role that endothelial nitric oxide synthase plays in post-exercise hypotension in spontaneously hypertensive rats. To accomplish this, rats were subjected to a single bout of dynamic exercise on a treadmill at 15 m/min for 20 min. L-nitroarginine methyl ester (L-NAME, 40 mg/kg, i.p.) significantly inhibited post-exercise hypotension (25+/-11 and 5+/-3 mm Hg, respectively; P<0.05). In addition, the superoxide anion generation was decreased, while the plasma nitrite production and serine phosphorylation of endothelial nitric oxide synthase were significantly elevated in spontaneously hypertensive rats at 30 min after the termination of exercise. Taken together, these data demonstrate that the increased phosphorylation of endothelial nitric oxide synthase plays a crucial role in the reduction of arterial pressure following a single bout of dynamic exercise in spontaneously hypertensive rats.

Midazolam inhibits tumor necrosis factor-alpha-induced endothelial activation: involvement of the peripheral benzodiazepine receptor.

BACKGROUND: Midazolam is widely used as an intravenous sedative. However, the role of midazolam on vascular endothelial activation is still unknown. The present study explores the action of midazolam on endothelial activation and its role to peripheral benzodiazepine receptor (PBR) in cultured human umbilical vein endothelial cells. METHODS: Intracellular localization of PBR in human umbilical vein endothelial cells was visualized with immunofluorescent staining. Monocyte adhesion and vascular cell adhesion molecule-1 expression were measured with monocyte adhesion assay and Western blot analysis. Involvement of PBR was assessed by using specific antagonists and small interfering RNA against PBR. RESULTS: PBR was localized in the mitochondria of human umbilical vein endothelial cells. Midazolam significantly inhibited tumor necrosis factor-alpha-induced vascular cell adhesion molecule-1 and monocyte adhesion in a dose-dependent manner (1-30 microM). The midazolam-mediated suppression on the tumor necrosis factor-alpha-induced vascular cell adhesion molecule-1 expression and monocyte adhesion were inhibited by the pretreatment of PK11195 and not inhibited by the flumazenil. Transfection of small interfering RNA for PBR decreased the expression of PBR (18 kDa) in human umbilical vein endothelial cells. Midazolam-mediated suppression on the tumor necrosis factor-alpha-induced vascular cell adhesion molecule-1 expression was abrogated by the transfection of small interfering RNA for PBR. CONCLUSION: These results suggest that midazolam has an inhibitory action on the endothelial activation and that its action is related to the activation of peripheral benzodiazepine receptor localized in mitochondria of the endothelial cells.

The extracellular role of Ref-1 as anti-inflammatory function in lipopolysaccharide-induced septic mice.

Apurinic/apyrimidinic endonuclease/redox factor-1 (Ref-1), a multifunctional protein secreted from stimulated cells, has been identified as a new serological biomarker. Despite recent reports on the role of Ref-1 in inflammation, the biological function of secreted Ref-1 remains unknown, especially in vivo. This study aimed to evaluate the possible roles of secreted Ref-1 in lipopolysaccharide-induced systemic inflammation in vivo. We generated a secretory Ref-1 adenoviral vector system, AdPPT-LS-Ref-1, by conjugation of preprotrypsin leading sequence (PPT-LS) with full-length Ref-1 sequences. Expression of tumor necrosis factor-α (TNF-α)-induced vascular cell adhesion molecule-1 (VCAM-1) in endothelial cells and lipopolysaccharide (LPS)-induced cyclooxygenase-2 in Raw264.7 cells was inhibited by secretory Ref-1, and this inhibitory effect was abrogated following neutralization of Ref-1 with anti-Ref-1 antibody. Plasma Ref-1 levels following administration of AdPPT-LS-Ref-1 (2 × 109 ifu, i.p.) for 24 h were substantially higher than those recorded following administration of Adßgal (84.6 ±â€¯7.2 ng/ml vs. 4.4 ±â€¯1.5 ng/ml). Treatment with LPS (10 mg/kg, i.v. for 6 h) markedly increased VCAM-1 expression, cathepsin or myeloperoxidase activity, which were significantly suppressed by treatment with AdPPT-LS-Ref-1. Furthermore, LPS-induced cytokines, such as TNF-α, interleukin (IL)-1ß, IL-6, and monocyte chemoattractant protein 1, were significantly inhibited in AdPPT-LS-Ref-1-treated mice. However, LPS-induced myeloperoxidase activities were not suppressed by treatment with the redox mutant of secretory Ref-1, AdPPT-LS-Ref-1(C65A/C93A), or wild-type AdRef-1. Collectively, these results suggest that secreted Ref-1 has anti-inflammatory properties and that its redox cysteine residue is associated with the anti-inflammatory activity in vivo. Furthermore, our findings indicate that secretory Ref-1 may be useful as a therapeutic biomolecule against systemic inflammation.