Herpesviruses and the Type Ⅲ Interferon System

Type Ⅲ interferons (IFNs) represent the most recently discovered group of IFNs.Together with type Ⅰ IFNs (e.g.IFN-α/β),type Ⅲ IFNs (IFN-λ) are produced as part of the innate immune response to virus infection,and elicit an anti-viral state by inducing expression of interferon stimulated genes (ISGs).It was initially thought that type Ⅰ IFNs and type Ⅲ IFNs perform largely redundant functions.However,it has become evident that type Ⅲ IFNs particularly play a major role in antiviral protection of mucosal epithelial barriers,thereby serving an important role in the first-line defense against virus infection and invasion at contact areas with the outside world,versus the generally more broad,potent and systemic antiviral effects of type Ⅰ IFNs.Herpesviruseses are large DNA viruses,which enter their host via mucosal surfaces and establish lifelong,latent infections.Despite the importance of mucosal epithelial cells in the pathogenesis of herpesviruses,our current knowledge on the interaction of herpesviruses with type Ⅲ IFN is limited and largely restricted to studies on the alphaherpesvirus herpes simplex virus (HSV).This review summarizes the current understanding about the role of IFN-λ in the immune response against herpesvirus infections.     

Comparison of the Regulation of β-Catenin Signaling by Type I,Type II and Type III Interferons in Hepatocellular Carcinoma Cells

Background/Objective

IFNs are a group of cytokines that possess potent antiviral and antitumor activities, while β-catenin pathway is a proliferative pathway involved in carcinogenesis. Interaction between these two pathways has not been well elaborated in hepatocellular carcinoma (HCC).

Methods

HCC cell lines, HepG2 and Huh7, were used in this study. β-catenin protein levels and corresponding signaling activities were observed by flow cytometry and luciferase assay, respectively. Cell proliferation was quantified by counting viable cells under microscope, and apoptosis by TUNEL assay. DKK1 and GSK3β levels were determined by flow cytometry. Secreted DKK1 was tested by ELISA. FLUD, S3I and aDKK1 were used to inhibit STAT1, STAT3 and DKK1 activities, respectively.

Results

Our findings show that all three types of IFNs, IFNα, IFNγ and IFNλ, are capable of inhibiting β-catenin signaling activity in HepG2 and Huh7 cells, where IFNγ was the strongest (p<0.05). They expressed suppression of cellular proliferation and induced apoptosis. IFNγ expressed greater induction ability when compared to IFNα and IFNλ (p<0.05). All tested IFNs could induce DKK1 activation but not GSK3β in HepG2 and Huh7 cells. IFNs induced STAT1 and STAT3 activation but by using specific inhibitors, we found that only STAT3 is vital for IFN-induced DKK1 activation and apoptosis. In addition, DKK1 inhibitor blocked IFN-induced apoptosis. The pattern of STAT3 activation by different IFNs is found consistent with the levels of apoptosis with the corresponding IFNs (p<0.05).

Conclusions

In hepatocellular carcinoma, all three types of IFNs are found to induce apoptosis by inhibiting β-catenin signaling pathway via a STAT3- and DKK1-dependent pathway. This finding points to a cross-talk between different IFN types and β-catenin signaling pathways which might be carrying a biological effect not only on HCC, but also on processes where the two pathways bridge.     

Conformational Analysis of the Type II and Type III Collagen α-1 Chain C-Telopeptides by 1H NMR and Circular Dichroism Spectroscopy

Abstract

The type II and type III collagen α-1 chain C-telopeptides are a 27 mer with the sequence NAc- GPGIDMSAFAGLGPREKGPDPLQYMRA and a 22mer, NAc-GGGVASLGAGEKGPVG- YGYEYR, respectively. Their conformations have been studied in CD₃OH/H₂O (80/20) solution by means of two-dimensional proton NMR and CD spectroscopy. Based on TOCSY and NOESY experiments, all resonances were assigned and the conformational properties were analyzed in terms of vicinal NH-H_α coupling constants, sequential and medium range NOEs and amide proton temperature coefficients.

The conformation of the type II C-telopeptide is essentially extended. Evidence from CD spectroscopy suggests that a very minor proportion of the peptide might be helical (ca. 8%), but the NMR data show no evidence for a non-linear structure. The observation of reduced amide proton temperature dependence coefficients in certain sections of the molecule can, in view of the absence of any other supporting evidence, only be interpreted in terms of local shielding from solvent for sterical reasons (large hydrophobic side-chains).

The conformation of the type III C-telopeptide is mostly extended except for a β-turn ranging from Gly⁸ to Glu¹¹, which is stabilized by a hydrogen-bond between NH of Glu¹¹ and the carbonyl group of Gly⁸. The low temperature coefficient of NH(Glu¹¹) and, in particular, the observation of a medium range NOE between H_α (A⁹) and NH(E¹¹) corroborate the existence of a β-turn in this region. Although spectral overlap prevents a precise conclusion with regard to the type of β-turn present, there is some evidence that it might be type II.     

Type II restriction endonucleases—a historical perspective and more

This article continues the series of Surveys and Summaries on restriction endonucleases (REases) begun this year in Nucleic Acids Research. Here we discuss ‘Type II’ REases, the kind used for DNA analysis and cloning. We focus on their biochemistry: what they are, what they do, and how they do it. Type II REases are produced by prokaryotes to combat bacteriophages. With extreme accuracy, each recognizes a particular sequence in double-stranded DNA and cleaves at a fixed position within or nearby. The discoveries of these enzymes in the 1970s, and of the uses to which they could be put, have since impacted every corner of the life sciences. They became the enabling tools of molecular biology, genetics and biotechnology, and made analysis at the most fundamental levels routine. Hundreds of different REases have been discovered and are available commercially. Their genes have been cloned, sequenced and overexpressed. Most have been characterized to some extent, but few have been studied in depth. Here, we describe the original discoveries in this field, and the properties of the first Type II REases investigated. We discuss the mechanisms of sequence recognition and catalysis, and the varied oligomeric modes in which Type II REases act. We describe the surprising heterogeneity revealed by comparisons of their sequences and structures.     

Type A-trichothecenes — Quantitative analysis using LC-MS and occurrence in Austrian maize and oats

During this study a method was developed for the quantitative determination of diacetoxyscirpenol (DAS), T-2 toxin and HT-2 toxin using deuterated T-2 toxin (T-2 d3 toxin) as an internal standard. The described method involves a clean up step of maize extract by the use of Mycosep® 227 columns a chromatographic separation on a Zorbax® bonus-RP-column (2,1×150mm) and the detection and quantification step on a mass spectrometer in SIM (Selected Ion Monitoring) mode.Data on the occurrence of three type A trichothecenes in Austrian maize, maize silage and oats were collected. It could be shown that maize and silage samples harvested in 2002 were only contaminated to a small extent with T-2 toxin (8% of the maize, 0% of the silage) and with HT-2 toxin (30% of the maize, 18% of the silage). But most of the analysed oats samples showed significant levels of T-2 toxin (64%) or HT-2 toxin (82%).     

Type I and II β-turns prediction using NMR chemical shifts

A method for predicting type I and II β-turns using nuclear magnetic resonance (NMR) chemical shifts is proposed. Isolated β-turn chemical-shift data were collected from 1,798 protein chains. One-dimensional statistical analyses on chemical-shift data of three classes β-turn (type I, II, and VIII) showed different distributions at four positions, (i) to (i + 3). Considering the central two residues of type I β-turns, the mean values of C_ο, C_α, H_N, and N_H chemical shifts were generally (i + 1) > (i + 2). The mean values of C_β and H_α chemical shifts were (i + 1) < (i + 2). The distributions of the central two residues in type II and VIII β-turns were also distinguishable by trends of chemical shift values. Two-dimensional cluster analyses on chemical-shift data show positional distributions more clearly. Based on these propensities of chemical shift classified as a function of position, rules were derived using scoring matrices for four consecutive residues to predict type I and II β-turns. The proposed method achieves an overall prediction accuracy of 83.2 and 84.2 % with the Matthews correlation coefficient values of 0.317 and 0.632 for type I and II β-turns, indicating that its higher accuracy for type II turn prediction. The results show that it is feasible to use NMR chemical shifts to predict the β-turn types in proteins. The proposed method can be incorporated into other chemical-shift based protein secondary structure prediction methods.     

α Cell Function and Gene Expression Are Compromised in Type 1 Diabetes

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Type I β-lactamases ofEnterobacter cloacae and resistance to β-lactam antibiotics

The interaction of type-I β-lactamases fromEnterobacter cloacae with diverse β-lactam compounds was examined. The ability of penicillin and cefoxitin to induce β-lactamase production in this strain was assessed. The effect of β-lactamase inhibitors was measured on β-lactamase extracts and on intact cells.E. cloacae 78 strain is a stably derepressed mutant showing limited susceptibility to a number of antibiotics except imipenem. Imipenem would therefore be the appropiate choice for therapy of infections caused by stably derepressed mutants ofEnterobacter sp. producing type-I β-lactamases.     

Type I IFN and TNFα cross-regulation in immune-mediated inflammatory disease: basic concepts and clinical relevance

A cross-regulation between type I IFN and TNFα has been proposed recently, where both cytokines are hypothesized to counteract each other. According to this model, different autoimmune diseases can be viewed as disequilibrium between both cytokines. As this model may have important clinical implications, the present review summarizes and discusses the currently available clinical evidence arguing for or against the proposed cross-regulation between TNFα and type I IFN. In addition, we review how this cross-regulation works at the cellular and molecular levels. Finally, we discuss the clinical relevance of this proposed cross-regulation for biological therapies such as type I IFN or anti-TNFα treatment.     

Expression and Localization of Type II Diacylglycerol Kinase Isozymes δ and η in the Developing Mouse Brain

The functions of type II diacylglycerol kinase (DGK) δ and -η in the brain are still unclear. As a first step, we investigated the spatial and temporal expression of DGKδ and -η in the brains of mice. DGKδ2, but not DGKδ1, was highly expressed in layers II–VI of the cerebral cortex; CA–CA3 regions and dentate gyrus of hippocampus; mitral cell, glomerular and granule cell layers of the olfactory bulb; and the granule cell layer in the cerebellum in 1- to 32-week-old mice. DGKδ2 was expressed just after birth, and its expression levels dramatically increased from weeks 1 to 4. A substantial amount of DGKη (η1/η2) was detected in layers II–VI of the cerebral cortex, CA1 and CA2 regions and dentate gyrus of the hippocampus, mitral cell and glomerular layers of the olfactory bulb, and Purkinje cells in the cerebellum of 1- to 32-week-old mice. DGKη2 expression reached maximum levels at P5 and decreased by 4 weeks, whereas DGKη1 increased over the same time frame. These results indicate that the expression patterns of DGK isozymes differ from each other and also from other isozymes, and this suggests that DGKδ and -η play distinct and specific roles in the brain.     

Integrated Model of Metabolism and Autoimmune Response in β-Cell Death and Progression to Type 1 Diabetes

Progression to type 1 diabetes is characterized by complex interactions of environmental, metabolic and immune system factors, involving both degenerative pathways leading to loss of pancreatic β-cells as well as protective pathways. The interplay between the degenerative and protective pathways may hold the key to disease outcomes, but no models have so far captured the two together. Here we propose a mathematical framework, an ordinary differential equation (ODE) model, which integrates metabolism and the immune system in early stages of disease process. We hypothesize that depending on the degree of regulation, autoimmunity may also play a protective role in the initial response to stressors. We assume that β-cell destruction follows two paths of loss: degenerative and autoimmune-induced loss. The two paths are mutually competing, leading to termination of the degenerative loss and further to elimination of the stress signal and the autoimmune response, and ultimately stopping the β-cell loss. The model describes well our observations from clinical and non-clinical studies and allows exploration of how the rate of β-cell loss depends on the amplitude and duration of autoimmune response.     

Type 2 Diabetes and Congenital Hyperinsulinism Cause DNA Double-Strand Breaks and p53 Activity in β Cells

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c-Cbl-Mediated Neddylation Antagonizes Ubiquitination and Degradation of the TGF-β Type II Receptor

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Highlights? c-Cbl is a NEDD8 E3 ligase of TβRII ? c-Cbl neddylates TβRII at Lys556 and Lys567 ? Neddylation stabilizes TβRII by regulating receptor endocytic routes ? Aberrant neddylation of TβRII is associated with leukemia     

Effect of Oil Type on Formation,Structure and Thermal Properties of γ-oryzanol and β-sitosterol-Based Organogels

Oil sources characterized of increasing viscosity and polarity (flax-seed oil, sunflower oil, extra virgin olive oil, triolein, castor oil) were gelled by using mixtures of β-sitosterol and γ-oryzanol (5, 10 and 20 % w/w). The gelling time, thermal properties as well as structure characteristics were determined. As the oil viscosity increased the gelling time increased. The effect of oil type resulted more evident as the structurant concentration decreased. Samples containing 5 % of the most viscous and polar castor oil did not gelled over the entire experiment. When gels were formed, the firmness of samples decreased in concomitance with modifications of thermal data as the oil viscosity increased. During storage at 20 °C the gels became stronger as consequence of the progression of the aggregation among sterol-sterol ester assemblages. Once again, less structurants were in the mixture more evident was the influence of oil type. These results were attributed to the increase of the difficulty of β-sitosterol and γ-oryzanol molecules to pack together as the oil viscosity increased.     

Angiotensin II Type 2 Receptor Decreases Transforming Growth Factor-β Type II Receptor Expression and Function in Human Renal Proximal Tubule Cells

Transforming growth factor-β (TGF-β), via its receptors, induces epithelial-mesenchymal transition (EMT) and plays an important role in the development of renal tubulointersitial fibrosis. Angiotensin II type 2 receptor (AT₂R), which mediates beneficial renal physiological functions, has received attention as a prospective therapeutic target for renoprotection. In this study, we investigated the effect and underlying mechanism of AT₂R on the TGF-β receptor II (TGF-βRII) expression and function in human proximal tubular cells (HK-2). Here, we show that the AT₂R agonist CGP42112A decreased TGF-βRII protein expression in a concentration- and time-dependent manner in HK-2 cells. The inhibitory effect of the AT₂R on TGF-βRII expression was blocked by the AT₂R antagonists PD123319 or PD123177. Stimulation with TGF-β1 enhanced EMT in HK-2 cells, which was prevented by pre-treatment with CGP42112A. One of mechanisms in this regulation is associated with the increased TGF-βRII degradation after activation of AT₂R. Furthermore, laser confocal immunofluorescence microscopy showed that AT₂R and TGF-βRII colocalized in HK-2 cells. AT₂R and TGF-βRII coimmunoprecipitated and this interaction was increased after AT₂R agonist stimulation for 30 min. The inhibitory effect of the AT₂R on TGF-βRII expression was also blocked by the nitric oxide synthase inhibitor L-NAME, indicating that nitric oxide is involved in the signaling pathway. Taken together, our study indicates that the renal AT₂R regulates TGF-βRII expression and function via the nitric oxide pathway, which may be important in the control of renal tubulointerstitial fibrosis.     

Calcium signaling in pancreatic β-cells in health and in Type 2 diabetes

Changes in cytosolic free Ca²⁺ concentration ([Ca²⁺]_c) play a crucial role in the control of insulin secretion from the electrically excitable pancreatic β-cell. Secretion is controlled by the finely tuned balance between Ca²⁺ influx (mainly through voltage-dependent Ca²⁺ channels, but also through voltage-independent Ca²⁺ channels like store-operated channels) and efflux pathways. Changes in [Ca²⁺]_c directly affect [Ca²⁺] in various organelles including the endoplasmic reticulum (ER), mitochondria, the Golgi apparatus, secretory granules and lysosomes, as imaged using recombinant targeted probes. Because most of these organelles have specific Ca²⁺ influx and efflux pathways, they mutually influence free [Ca²⁺] in the others. In this article, we review the mechanisms of control of [Ca²⁺] in various compartments and particularly the cytosol, the endoplasmic reticulum ([Ca²⁺]_ER), acidic stores and mitochondrial matrix ([Ca²⁺]_mito), focusing chiefly on the most important physiological stimulus of β-cells, glucose. We also briefly review some alterations of β-cell Ca²⁺ homeostasis in Type 2 diabetes.