The heparin-binding domain of VEGF165 directly binds to integrin αvß3 and VEGFR2/KDR D1: a potential mechanism of negative regulation of VEGF165 signaling by αvß3.

VEGF-A is a key cytokine in tumor angiogenesis and a major therapeutic target for cancer. VEGF165 is the predominant isoform of VEGF-A, and it is the most potent angiogenesis stimulant. VEGFR2/KDR domains 2 and 3 (D2D3) bind to the N-terminal domain (NTD, residues 1-110) of VEGF165. Since removal of the heparin-binding domain (HBD, residues 111-165) markedly reduced the mitogenic activity of the growth factor, it has been proposed that the HBD plays a critical role in the mitogenicity of VEGF165. Here, we report that αvß3 specifically bound to the isolated VEGF165 HBD but not to VEGF165 NTD. Based on docking simulation and mutagenesis, we identified several critical amino acid residues within the VEGF165 HBD required for αvß3 binding, i.e., Arg123, Arg124, Lys125, Lys140, Arg145, and Arg149. We discovered that VEGF165 HBD binds to the KDR domain 1 (D1) and identified that Arg123 and Arg124 are critical for KDR D1 binding by mutagenesis, indicating that the KDR D1-binding and αvß3-binding sites overlap in the HBD. Full-length VEGF165 mutant (R123A/R124A/K125A/K140A/R145A/R149A) defective in αvß3 and KDR D1 binding failed to induce ERK1/2 phosphorylation, integrin ß3 phosphorylation, and KDR phosphorylation and did not support proliferation of endothelial cells, although the mutation did not affect the KDR D2D3 interaction with VEGF165. Since ß3-knockout mice are known to show enhanced VEGF165 signaling, we propose that the binding of KDR D1 to the VEGF165 HBD and KDR D2D3 binding to the VEGF165 NTD are critically involved in the potent mitogenicity of VEGF165. We propose that binding competition between KDR and αvß3 to the VEGF165 HBD endows integrin αvß3 with regulatory properties to act as a negative regulator of VEGF165 signaling.

The heparin-binding domain of VEGF165 directly binds to integrin αvß3 and plays a critical role in signaling.

VEGF-A is a key cytokine in tumor angiogenesis and a major therapeutic target for cancer. VEGF165 is the predominant isoform and is the most potent angiogenesis stimulant. VEGFR2/KDR domains 2 and 3 (D2D3) bind to the N-terminal domain (NTD, residues 1-110) of VEGF165. Since removal of the heparin-binding domain (HBD, residues 111-165) markedly reduced the mitogenic activity of VEGF165, it has been proposed that the HBD plays a critical role in the mitogenicity of VEGF165. Integrin αvß3 has been shown to bind to VEGF165, but the role of integrin αvß3 in VEGF165 signaling are unclear. Here we describe that αvß3 specifically bound to the isolated HBD, but not to the NTD. We identified several critical amino acid residues in HBD for integrin binding (Arg-123, Arg-124, Lys-125, Lys-140, Arg-145, and Arg-149) by docking simulation and mutagenesis, and generated full-length VEGF165 that is defective in integrin binding by including mutations in the HBD. The full-length VEGF165 mutant defective in integrin binding (R123A/R124A/K125A/K140A/R145A/R149A) was defective in ERK1/2 phosphorylation, integrin ß3 phosphorylation, and KDR phosphorylation, although the mutation did not affect KDR binding to VEGF165. We propose a model in which VEGF165 induces KDR (through NTD)-VEGF165 (through HBD)-integrin αvß3 ternary complex formation on the cell surface and this process is critically involved in potent mitogenicity of VEGF165.

Dexmedetomidine alleviates intestinal barrier dysfunction and inflammatory response in mice via suppressing TLR4/MyD88/NF-κB signaling in an experimental model of ulcerative colitis.

INTRODUCTION: Ulcerative colitis (UC) is a nonspecific intestinal inflammatory disease. Dexmedetomidine (DEX) is a selective alpha 2-adrenergic receptor agonist commonly used for analgesia and sedation in intensive care units. Herein, the role and mechanism of DEX in dextran sulfate sodium (DSS)-induced colitis was explored. MATERIALS AND METHODS: A murine model of DSS-induced colitis was established by adding 3.5% (w/v) DSS in drinking water to C57BL/6J female mice. The severity of colitis was measured by the disease activity index (DAI) score, colon length and body weight of mice. The serum concentration and mRNA levels of inflammatory cytokines in colon tissues were assessed by ELISA and RT-qPCR, respectively. Protein levels of apoptotic markers, tight junction proteins and genes involved in the TLR4/MyD88/NF-κB signaling were quantified utilizing Western blotting. The pathological changes of colon tissues were evaluated by hematoxylin-eosin (HE) staining and histological score. Intestinal permeability in vivo was assessed by fluorescein isothiocyanate (FITC)-dextran (FITC-D) administration. TUNEL assay was used to determine cell apoptosis in the intestinal epithelium. RESULTS: DSS administration resulted in weight loss, shortening of the colon, increased DAI score, histological abnormalities, and increased serum FITC-D levels in mice, all of which were reversed by DEX injection. Moreover, DEX attenuated DSS-triggered inflammatory response, intestinal barrier injury and intestinal epithelial cell apoptosis. Mechanically, DEX inactivated the TLR4/MyD88/NF-κB signaling in the colon tissues. CONCLUSIONS: DEX exerts beneficial effects against the intestinal barrier dysfunction, inflammatory response, and apoptosis of intestinal epithelial cells via inactivation of the TLR4/MyD88/NF-κB signaling in mice with DSS-induced colitis.

Combining CHA2DS2-VASc score into RCRI for prediction perioperative cardiovascular outcomes in patients undergoing non-cardiac surgery: a retrospective pilot study.

BACKGROUND: Treatment decisions in patients undergoing non-cardiac surgery are based on clinical assessment. The Revised Cardiac Risk Index (RCRI) is pragmatic and widely used but has only moderate discrimination. We aimed to test the efficacy of the CHA2DS2-VASc score and the combination of CHA2DS2-VASc and RCRI to predict perioperative risks for non-cardiac surgery. METHODS: This pre-specified analysis was performed in a retrospective cohort undergoing intra-abdominal surgery in our center from July 1st, 2007 to June 30th, 2008. The possible association between the baseline characteristics (as defined by CHA2DS2-VASc and RCRI) and the primary outcome of composite perioperative cardiac complications (myocardial infarction, cardiac ischemia, heart failure, arrhythmia, stroke, and/or death) and secondary outcomes of individual endpoints were explored using multivariate Logistic regression. The area under the receiver operating characteristic curve (C-statistic) was used for RCRI, CHA2DS2-VASc, and the combined models, and the net reclassification improvement (NRI) was calculated to assess the additional discriminative ability. RESULTS: Of the 1079 patients (age 57.5 ± 17.0 years), 460 (42.6%) were women. A total of 83 patients (7.7%) reached the primary endpoint. Secondary outcomes included 52 cardiac ischemic events, 40 myocardial infarction, 20 atrial fibrillation, 18 heart failure, four strokes, and 30 deaths. The endpoint events increased with the RCRI and CHA2DS2-VASc grade elevated (P < 0.05 for trend). The RCRI showed a moderate predictive ability with a C-statistics of 0.668 (95%CI 0.610-0.725) for the composite cardiac outcome. The C-statistics for the CHA2DS2-VASc was 0.765 (95% CI 0.709-0.820), indicating better performance than the RCRI (p = 0.011). Adding the CHA2DS2-VASc to the RCRI further increased the C-statistic to 0.774(95%CI 0.719-0.829), improved sensitivity, negative predictive value, and enhanced reclassification in reference to RCRI. Similar performance of the combined scores was demonstrated in the analysis of individual secondary endpoints. The best cut-off of a total of 4 scores was suggested for the combined CHA2DS2-VASc and RCRI in the prediction of the perioperative cardiac outcomes. CONCLUSIONS: The CHA2DS2-VASc score significantly enhanced risk assessment for the composite perioperative cardiovascular outcome in comparison to traditional RCRI risk stratification. Incorporation of CHA2DS2-VASc scores into clinical-decision making to improve perioperative management in patients undergoing non-cardiac surgery warrants consideration.

Differences in perioperative cardiovascular outcomes in elderly male and female patients undergoing intra-abdominal surgery: a retrospective cohort study.

OBJECTIVE: Perioperative cardiovascular events constitute the majority of complications in noncardiac surgery. Older and female patients have been less investigated. We aimed to evaluate differences in perioperative cardiovascular outcomes by age and sex. METHODS: We enrolled 1079 patients (57.5 ± 17.0 years, 42.6% women) undergoing intra-abdominal surgery from July 2007 to June 2008 and compared occurrence of perioperative cardiac events by age (≥65 vs. <65 years) and sex. Multivariable logistic regression was used to investigate associations between age, sex, and outcomes. RESULTS: Age ≥65 years was associated with perioperative myocardial infarction (MI) (odds ratio [OR] 2.9, 95% confidence interval [CI]: 1.3-6.6) and total cardiovascular events (OR 2.4, 95% CI: 1.3-4.2). Age ≥65 years was associated with higher perioperative MI risks in men (OR 4.7, 95% CI: 1.3-17.6) than in women (OR 3.1, 95% CI: 1.2-8.3). Advanced age was associated with heart failure in women (OR 13.9, 95% CI: 1.7-110.5). Female sex was a risk factor for heart failure in elderly patients (OR 4.2, 95% CI: 1.1-15.7). CONCLUSIONS: Advanced age appeared to be associated with increased perioperative cardiac risk but differed by sex. Tailored strategies should be considered with respect to the patient's sex.

Urotensin II promotes secretion of LTB4 through 5-lipoxygenase via the UT-ROS-Akt pathway in RAW264.7 macrophages.

INTRODUCTION: Urotensin II (UII) is an important vasoactive peptide involved in the pathogenesis of atherosclerosis. Monocytes/macrophages play important roles in every step of atherosclerosis. Although UII has a chemoattractant effect on monocytes, it is unclear whether UII regulates inflammatory responses in macrophages. The present study sought to explore whether UII can promote leukotriene B4 (LTB4) production by macrophages. MATERIAL AND METHODS: The mRNA expression level of LTB4 and 5-lipoxygenase were determined by real-time polymerase chain reaction. The protein level of LTB4 and 5-lipoxygenase expression was assayed by enzyme-linked immunosorbent assay and Western blot, respectively. Western blot analysis was also employed to determine the phosphorylated forms of Akt. Reactive oxygen species (ROS) level was detected by the fluorescent probe 2',7'-dichlorofluorescin diacetate and fluorescence intensity was measured with a multiwell fluorescence plate reader. RESULTS: Urotensin II promoted LTB4 release and increased 5-lipoxygenase expression in a concentration- and time-dependent manner in RAW264.7 cells. Leukotriene B4 production and 5-lipoxygenase expression were decreased by blocking the UII receptor (UT) with urantide, eliminating ROS with N-acetylcysteine and diphenyliodonium, and inhibiting Akt phosphorylation with LY294002. UII significantly elevated ROS production, whereas urantide, N-acetylcysteine and diphenyliodonium substantially attenuated this effect. UII also enhanced Akt phosphorylation significantly, and this effect was potently inhibited by urantide, N-acetylcysteine, diphenyliodonium and LY294002. CONCLUSIONS: Urotensin II may promote 5-lipoxygenase expression and LTB4 release in RAW264.7 macrophages via UT-ROS-Akt pathways. These results indicate that UII may participate in macrophage activation and suggest a potential new mechanism underlying atherosclerosis.

A new species of Scytalidium causing slippery scar on cultivated Auricularia polytricha in China.

Slippery scar is one of the most destructive diseases encountered in the cultivation of Auricularia polytricha (hairy wood ear); however, the identity of the pathogenic agent has remained uncertain. This study was designed to identify the causative pathogen of slippery scar in A. polytricha and to investigate the taxonomic classification of the pathogen by morphological observations, in vivo pathogenicity tests, and molecular evidences of ITS and RPB2 sequences. The results showed that the pathogen was a new Scytalidium species, here named Scytalidium auriculariicola. Scytalidium auriculariicola was characterized by its rapid growth rate, the catenate conidia of variable size, and the pale brown to brown chlamydoconidia. Phylogenetic analyses based on internal transcribed spacer regions and RPB2 sequences on the pathogen isolated and related species supported that S. auriculariicola was a true Scytalidium species. It was congeneric with and close to Scytalidium lignicola, the type species of Scytalidium. However, it differed from the latter species in the size of conidia, 33 different nucleotide bases in ITS sequences and 30 different nucleotide bases in RPB2 sequences.

Plasma levels and diagnostic value of catestatin in patients with heart failure.

Catestatin (CST) is an endogenous neuropeptide with multiple cardiovascular activities. The study is to investigate circulating CST levels in heart failure (HF) patients and to evaluate the role of CST as a biomarker for HF. Plasma CST concentrations were measured by enzyme-linked immunosorbent assay in 228 HF patients and 172 controls. Plasma CST gradually increased in patients from NYHA class I to class IV. No significant differences in CST were found among NYHA I, NYHA II patients and controls. Plasma CST in NYHA III and IV patients was higher compared to other groups. Plasma CST levels in HF patients after treatment were similar to admission, but still higher than controls. In a subgroup analysis among the patients with NYHA class III or IV, patients with ischemic etiology had significantly higher CST. Plasma CST levels were similar between patients with preserved and reduced ejection fraction. Multivariable analysis showed that NYHA classes, the etiology of HF (ischemic or not) and estimated glomerular filtration rate independently predicted plasma LogCST levels (P<0.05). The area under ROC for CST and BNP in moderate to severe HF diagnosis was 0.626 and 0.831, respectively, combining CST and BNP did not improve the accuracy.

Urotensin II promotes the production of LTC4 in rat aortic adventitial fibroblasts through NF-κB-5-LO pathway by p38 MAPK and ERK activations.

Adventitia is the outer part of the arterial wall where the inflammatory response often occurs. Urotensin II (UII) is a potent vasoconstrictive peptide that also promotes the inflammatory process in patients with cardiovascular disease. Leukotriene C4 (LTC4), a lipid mediator, was recently found to play a role in the inflammatory process in the artery. We hypothesized that the adventitia is one of the resources of LTC4 and that UII may promote LTC4 production through the 5-LO (5-lipoxygenase) pathway in adventitial fibroblasts. Rat adventitial fibroblasts were isolated and incubated in serum-free medium with either UII alone or in combination with inhibitors of p38 MAPK, ERK, and UII receptors. The expression of 5-LO was detected using real-time polymerase chain reaction and Western blot. The translocation and binding activity of nuclear factor (NF)-κB were measured using immunofluorescence and electrophoretic mobility shift assay, respectively. The production of LTC4 was measured by enzyme-linked immunosorbent assay. The results indicated that: (1) adventitial fibroblasts were a source of LTC4 production; (2) UII increased the expression of the 5-LO mRNA and the protein by NF-κB activation through p38 MAPK and ERK pathways; and (3) UII promoted the LTC4 release in fibroblasts through the 5-LO pathway by p38 MAPK and ERK activations. The 5-LO pathway mediates LTC4 production, which may be a new mechanism in the pathogenesis of the vascular adventitial inflammation caused by UII.

Plasma catecholamine release-inhibitory peptide catestatin in patients with essential hypertension.

BACKGROUND: Catestatin plays an important role in the adjustment of blood pressure and cardiac function. We investigated levels of plasma catestatin in essential hypertension and the relationship between catestatin and left ventricular hypertrophy. METHODS: Plasma was collected from 136 patients with essential hypertension and 61 healthy controls. Plasma catestatin was measured by enzyme-linked immunosorbent assay (ELISA). Plasma norepinephrine was measured by high-performance liquid chromatography. All patients underwent echocardiography, measurement of fasting blood glucose, body mass index (BMI) and lipid levels. RESULTS: Plasma levels of catestatin and norepinephrine were significantly higher in patients with essential hypertension than in normal controls (both P<0.01). The ratio of catestatin to norepinephrine was significantly lower in patients with essential hypertension than in normal controls (P<0.01). In patients with essential hypertension, plasma norepinephrine level was significantly higher in patients with than without left ventricular hypertrophy (P<0.01). Plasma catestatin level was lower, but not significantly, in patients with than without left ventricular hypertrophy. The ratio of catestatin to norepinephrine was significantly lower in patients with than without left ventricular hypertrophy (P<0.01). CONCLUSION: Plasma catestatin is elevated in patients with essential hypertension. The ratio of catestatin to norepinephrine was lower in patients with left ventricular hypertrophy. Catestatin might participate in the development of hypertension and left ventricular hypertrophy.