Kaposi's sarcoma-associated herpesvirus OX2 glycoprotein activates myeloid-lineage cells to induce inflammatory cytokine production

Kaposi's sarcoma is an inflammatory cytokine-mediated angioproliferative disease which is triggered by infection by Kaposi's sarcoma-associated herpesvirus (KSHV). KSHV contains an open reading frame, K14, that has significant homology with cellular OX2, designated viral OX2 (vOX2). In this report, we demonstrate that vOX2 encodes a glycosylated cell surface protein with an apparent molecular mass of 55 kDa. Purified glycosylated vOX2 protein dramatically stimulated primary monocytes, macrophages, and dendritic cells to produce the inflammatory cytokines interleukin 1beta (IL-1beta), IL-6, monocyte chemoattractant protein 1, and TNF-alpha. Furthermore, expression of vOX2 on B lymphocytes stimulated monocytes to produce inflammatory cytokines in mixed culture. These results demonstrate that like its cellular counterpart, vOX2 targets myeloid-lineage cells, but unlike cellular OX2, which delivers a restrictive signal, KSHV vOX2 provides an activating signal, resulting in the production of inflammatory cytokines. Thus, this is a novel viral strategy where KSHV has acquired the cellular OX2 gene to induce inflammatory cytokine production, which potentially promotes the cytokine-mediated angiogenic proliferation of KSHV-infected cells.     

Oxidative stress caused by pyocyanin impairs CFTR Cl(-) transport in human bronchial epithelial cells

Pyocyanin (N-methyl-1-hydroxyphenazine), a redox-active virulence factor produced by the human pathogen Pseudomonas aeruginosa, is known to compromise mucociliary clearance. Exposure of human bronchial epithelial cells to pyocyanin increased the rate of cellular release of H(2)O(2) threefold above the endogenous H(2)O(2) production. Real-time measurements of the redox potential of the cytosolic compartment using the redox sensor roGFP1 showed that pyocyanin (100 microM) oxidized the cytosol from a resting value of -318+/-5 mV by 48.0+/-4.6 mV within 2 h; a comparable oxidation was induced by 100 microM H(2)O(2). Whereas resting Cl(-) secretion was slightly activated by pyocyanin (to 10% of maximal currents), forskolin-stimulated Cl(-) secretion was inhibited by 86%. The decline was linearly related to the cytosolic redox potential (1.8% inhibition/mV oxidation). Cystic fibrosis bronchial epithelial cells homozygous for DeltaF508 CFTR failed to secrete Cl(-) in response to pyocyanin or H(2)O(2), indicating that these oxidants specifically target the CFTR and not other Cl(-) conductances. Treatment with pyocyanin also decreased total cellular glutathione levels to 62% and cellular ATP levels to 46% after 24 h. We conclude that pyocyanin is a key factor that redox cycles in the cytosol, generates H(2)O(2), depletes glutathione and ATP, and impairs CFTR function in Pseudomonas-infected lungs.     

Long-Term Clinical Outcome of Internal Globus Pallidus Deep Brain Stimulation for Dystonia

Background

GPi (Internal globus pallidus) DBS (deep brain stimulation) is recognized as a safe, reliable, reversible and adjustable treatment in patients with medically refractory dystonia.

Objectives

This report describes the long-term clinical outcome of 36 patients implanted with GPi DBS at the Neurosurgery Department of Seoul National University Hospital.

Methods

Nine patients with a known genetic cause, 12 patients with acquired dystonia, and 15 patients with isolated dystonia without a known genetic cause were included. When categorized by phenomenology, 29 patients had generalized, 5 patients had segmental, and 2 patients had multifocal dystonia. Patients were assessed preoperatively and at defined follow-up examinations postoperatively, using the Burke-Fahn-Marsden dystonia rating scale (BFMDRS) for movement and functional disability assessment. The mean follow-up duration was 47 months (range, 12–84)

Results

The mean movement scores significantly decreased from 44.88 points preoperatively to 26.45 points at 60-month follow up (N = 19, P = 0.006). The mean disability score was also decreased over time, from 11.54 points preoperatively to 8.26 points at 60-month follow up, despite no statistical significance (N = 19, P = 0.073). When analyzed the movement and disability improvement rates at 12-month follow up point, no significant difference was noted according to etiology, disease duration, age at surgery, age of onset, and phenomenology. However, the patients with DYT-1 dystonia and isolated dystonia without a known genetic cause showed marked improvement.

Conclusions

GPi DBS is a safe and efficient therapeutic method for treatment of dystonia patients to improve both movement and disability. However, this study has some limitations caused by the retrospective design with small sample size in a single-center.     

Assignment of heme methyl 1H-NMR resonances of high-spin and low-spin ferric complexes of cytochrome p450cam using one-dimensional and two-dimensional paramagnetic signals enhancement (PASE) magnetization transfer experiments.

An 1H-NMR study of ferric cytochrome P450cam in different paramagnetic states was performed. Assignment of three heme methyl resonances of the isocyanide adduct of cytochrome P450 in the ferric low-spin state was recently performed using electron exchange in the presence of putidaredoxin [Mouro, C., Bondon, A., Jung, C., Hui Bon Hoa, G., De Certaines, J.D., Spencer, R.G.S. & Simonneaux, G. (1999) FEBS Lett. 455, 302-306]. In this study, heme methyl protons of cytochrome P450 in the native high-spin and low-spin states were assigned through one-dimensional and two-dimensional magnetization transfer spectroscopy using the paramagnetic signals enhancement (PASE) method. The order of the methyl proton chemical shifts is inverted between high-spin and low-spin states. The methyl order observed in the ferric low-spin isocyanide complexes is related to the orientation of the cysteinate ligand.     

House dust mite extract activates apical Cl− channels through protease‐activated receptor 2 in human airway epithelia

Adequate fluid secretion from airway mucosa is essential for maintaining mucociliary clearance, and fluid hypersecretion is a prominent feature of inflammatory airway diseases such as allergic rhinitis. House dust mite extract (HDM) has been reported to activate protease‐activated receptors (PARs), which play various roles in airway epithelia. However, the role of HDM in regulating ion transporters and fluid secretion has not been investigated. We examined the effect of HDM on ion transport in human primary nasal epithelial cells. The Ca²⁺‐sensitive dye Fura2‐AM was used to determine intracellular Ca²⁺ concentration ([Ca²⁺]_i) by means of spectrofluorometry in human normal nasal epithelial cells (NHNE). Short‐circuit current (Isc) was measured using Ussing chambers. Fluid secretion from porcine airway mucosa was observed by optical measurement. HDM extract (10 µg/Ml) effectively cleaved the PAR‐2 peptide and induced an increase of [Ca²⁺]_i that was abolished by desensitization with trypsin, but not with thrombin. Apical application of HDM‐induced Isc sensitive to both a cystic fibrosis transmembrane conductance regulator (CFTR) inhibitor and a Ca²⁺‐activated Cl^? channel (CaCC) inhibitor. HDM extract also stimulated fluid secretion from porcine airway mucosa. HDM extract activated PAR‐2 and apical Cl^? secretion via CaCC and CFTR, and HDM‐induced fluid secretion in porcine airway mucosa. Our results suggest a role for PAR‐2 in mucociliary clearance and fluid hypersecretion of airway mucosa in response to air‐borne allergens such as HDM. J. Cell. Biochem. 109: 1254–1263, 2010. © 2010 Wiley‐Liss, Inc.     

Anti-apoptotic effect of magnolol in myocardial ischemia and reperfusion injury requires extracellular signal-regulated kinase1/2 pathways in rat in vivo

Magnolol, an active component extracted from Magnolia officinalis, has been reported to have protective effect on ischemia and reperfusion (I/R)-induced injury in experimental animals. The aim of the present investigation was to further evaluate the mechanism(s) by which magnolol reduces I/R-induced myocardial injury in rats in vivo. Under anesthesia, left anterior descending (LAD) coronary artery was occluded for 30 min followed by reperfusion for 24 h (for infarct size and cardiac function analysis). In some experiments, reperfusion was limited to 1 h or 6 h for analysis of biochemical and molecular events. Magnolol and DMSO solution (vehicle) were injected intra-peritoneally 1 h prior to I/R insult. The infarct size was measured by TTC technique and heart function was monitored by Millar Catheter. Apoptosis related events such as p-ERK, p-Bad, Bcl-xl and cytochrome c expression were evaluated by Western blot analysis and myocardial caspase-3 activity was also measured. Magnolol (10 mg/kg) reduced infarct size by 50% (P < 0.01 versus vehicle), and also improved I/R-induced myocardial dysfunction. Left ventricular systolic pressure and positive and negative maximal values of the first derivative of left ventricular pressure (dP/dt) were significantly improved in magnolol-treated rats. Magnolol increased the expression of phosphor ERK and Bad which resulted in inhibition of myocardial apoptosis as evidenced by TUNEL analysis and DNA laddering experiments. Application of PD 98059, a selective MEK1/2 inhibitor, strongly antagonized the effect of magnolol. Taken together, we concluded that magnolol inhibits apoptosis through enhancing the activation of ERK1/2 and modulation of the Bcl-xl proteins which brings about reduction of infarct size and improvement of cardiac function in I/R-induced injury.     

Investigation of a Family with Autosomal Dominant Dilated Cardiomyopathy Defines a Novel Locus on Chromosome 2q14-q22

Dilated cardiomyopathy (DCM) is a leading cause of heart failure and the most frequent indication for heart transplantation in young patients. Probably >25% of DCM cases are of familial etiology. We report here genetic localization in a three-generation German family with 12 affected individuals with autosomal dominant familial DCM characterized by ventricular dilatation, impaired systolic function, and conduction disease. After exclusion of known DCM loci, we performed a whole-genome screen and detected linkage of DCM to chromosome 2q14-q22. Investigation of only affected individuals defines a 24-cM interval between markers D2S2224 and D2S2324; when unaffected individuals are also included, the critical region decreases to 11 cM between markers D2S2224 and D2S112, with a peak LOD score of 3.73 at recombination fraction 0 at D2S2339. The identification of an additional locus for familial autosomal dominant DCM underlines the genetic heterogeneity and may assist in the elucidation of the causes of this disease.     

Apoptosis signal-regulating kinase 1 regulates the expression of caspase-11

Caspase-11 is an inducible caspase involved in the regulation of cell death and inflammation. In the present study, we examined whether apoptosis signal-regulating kinase 1 (Ask1)-mediated signaling pathway is involved in the expression of caspase-11 induced by lipopolysaccharide (LPS). We found that the induction of caspase-11 was suppressed by the inhibitors of NADPH oxidase (Nox) or knockdown of Nox4 that acts downstream of toll-like receptor 4 and generates Ask1-activating reactive oxygen species. Overexpression of dominant negative tumor necrosis factor receptor associate factor 6 also suppressed the induction of caspase-11. Importantly, knockdown or dominant negative form of Ask1 suppressed the induction of caspase-11 following LPS stimulation. Taken together, our results show that Ask1 regulates the expression of caspase-11 following LPS stimulation.