Interplay of oxidative, nitrosative/nitrative stress, inflammation, cell death and autophagy in diabetic cardiomyopathy

Diabetes is a recognized risk factor for cardiovascular diseases and heart failure. Diabetic cardiovascular dysfunction also underscores the development of diabetic retinopathy, nephropathy and neuropathy. Despite the broad availability of antidiabetic therapy, glycaemic control still remains a major challenge in the management of diabetic patients. Hyperglycaemia triggers formation of advanced glycosylation end products(AGEs), activates protein kinase C, enhances polyol pathway, glucose autoxidation, which coupled with elevated levels of free fatty acids, and leptin have been implicated in increased generation of superoxide anion by mitochondria, NADPH oxidases and xanthine oxidoreductase in diabetic vasculature and myocardium. Superoxide anion interacts with nitric oxide forming the potent toxin peroxynitrite via diffusion limited reaction, which in concert with other oxidants triggers activation of stress kinases, endoplasmic reticulum stress, mitochondrial and poly(ADP-ribose) polymerase 1-dependent cell death, dysregulates autophagy/mitophagy, inactivates key proteins involved in myocardial calcium handling/contractility and antioxidant defense, activates matrix metalloproteinases and redox-dependent pro-inflammatory transcription factors (e.g. nuclear factor kappaB) promoting inflammation, AGEs formation, eventually culminating in myocardial dysfunction, remodeling and heart failure. Understanding the complex interplay of oxidative/nitrosative stress with pro-inflammatory, metabolic and cell death pathways is critical to devise novel targeted therapies for diabetic cardiomyopathy, which will be overviewed in this brief synopsis. This article is part of a Special Issue entitled: Autophagy and protein quality control in cardiometabolic diseases

Implementation Of The Technical Interoperability For TAF TSI Subsystem In Freight Operation

The article describes the cooperation between freight railway undertaking and carriers with regard to implementation of the TAF TSI into operation. It suggests for interfaces between railway undertaking/carrier which are important for success application of the TAF TSI and defines limitations which must be eliminated during the implementation of the TAF TSI into operation. Technical specification of interoperability for the telematics applications for freight is one of the subsystems of railway interoperability of which implementation into operation is mandatory in accordance with Directive of the European parliament (62/2006 and 328/2012)

Performance uniformity evaluation of two SensL\u27s SiPM modules

Minimization of the channel-to-channel variation of silicon photomultiplier (SiPM) array is of great importance in achieving high performance for SiPM based imaging detectors. The purpose of this study was to characterize the operating parameters of a large-area SiPM based detector module with 12x12 pixel array (SensL\u27s ArraySM-4P9) in order to develop an optimal multiplexing readout for high-resolution SPECT imaging. Two versions of SensL\u27s SiPM arrays were investigated in this study. The previous ArraySL-4 version has an array of 4x4 pixels with 3x3mm2 pixel size and the new AarraySM-4p9 version consists of a 3x3 matrix of the 4x4 pixels SiPM modules. The current versus voltage (I-V) characteristics of individual SiPM pixels were measured to extract information of its breakdown voltage and dark current. The energy spectrum of individual pixels coupling with a 1x1x3mm3 LYSO crystal was measured using 22Na and 137Cs sources. The test results show that the previous ArraySL-4 version has larger channel-to-channel variations in breakdown voltage and dark current than the newer AarraySM-4p9 version. The new large-area ArraySM-4P9 SiPM module with 12x12 pixels shows very small breakdown voltage variations within ±0.1V at operating voltage of ∼27V and dark current variations within ±0.4nA of ∼1nA over the entire 144 pixel elements. The measured energy resolution of an individual SiPM pixel with a 1x1x3mm3 LYSO crystal is ∼16% at energy of 662keV. In conclusion, the new SensL\u27s AarraySM-4p9 ArraySM has much better improved property than the previous ArraySL-4 version. The excellent performance uniformity of the large-area ArraySM-4P9 SiPM module is good for multiplexed readout approach in the development of high-performance and cost-effective compact imaging detectors. 2013 IEEE

A novel method for in silico assessment of Methionine oxidation risk in monoclonal antibodies: Improvement over the 2-shell model

Over the past decade, therapeutic monoclonal antibodies (mAbs) have established their role as valuable agents in the treatment of various diseases ranging from cancers to infectious, cardiovascular and autoimmune diseases. Reactive groups of the amino acids within these proteins make them susceptible to many kinds of chemical modifications during manufacturing, storage and in vivo circulation. Among these reactions, the oxidation of methionine residues to their sulfoxide form is a commonly observed chemical modification in mAbs. When the oxidized methionine is in the complementarity-determining region (CDR), this modification can affect antigen binding and thus abrogate biological activity. For these reasons, it is essential to identify oxidation liabilities during the antibody discovery and development phases. Here, we present an in silico method, based on protein modeling and molecular dynamics simulations, to predict the oxidation-liable residues in the variable region of therapeutic antibodies. Previous studies have used the 2-shell water coordination number descriptor (WCN) to identify methionine residues susceptible to oxidation. Although the WCN descriptor successfully predicted oxidation liabilities when the residue was solvent exposed, the method was much less accurate for partially buried methionine residues. Consequently, we introduce a new descriptor, WCN-OH, that improves the accuracy of prediction of methionine oxidation susceptibility by extending the theoretical framework of the water coordination number to incorporate the effects of polar amino acids side chains in close proximity to the methionine of interest

Representation of the two-shell water coordination number (WCN) and the WCN-OH variant.

(A) For a methionine with the side chain exposed to the solvent, the water molecules within 6 Å from the sulfur atom are shown. (B) For a methionine with the side chain only partially exposed to the solvent, water molecules and side chains containing a hydroxyl group are shown. Carbon atoms are colored in cyan, oxygen in red, hydrogen in gray, nitrogen in blue and sulfur in yellow. The sphere represents the 2-solvation shell (radius 6 Å).</p

Confusion matrices for the in silico prediction of the oxidation events of the 7 mAbs and 2 ADCs.

Confusion matrices reports TP, FN on the first row and FP, TN on the second row. Sensitivity calculated as TP/(TP+FN); Specificity calculated as TN/(TN+FP). TP = True Positive, TN = True Negative, FP = False Positive, FN = False Negative. Error for the sensitivity and specificity were estimated from 50 bootstrap replicates.</p