Hyperactivation of Nrf2 increases stress tolerance at the cost of aging acceleration due to metabolic deregulation.

Metazoans viability depends on their ability to regulate metabolic processes and also to respond to harmful challenges by mounting anti-stress responses; these adaptations were fundamental forces during evolution. Central to anti-stress responses are a number of short-lived transcription factors that by functioning as stress sensors mobilize genomic responses aiming to eliminate stressors. We show here that increased expression of nuclear factor erythroid 2-related factor (Nrf2) in Drosophila activated cytoprotective modules and enhanced stress tolerance. However, while mild Nrf2 activation extended lifespan, high Nrf2 expression levels resulted in developmental lethality or, after inducible activation in adult flies, in altered mitochondrial bioenergetics, the appearance of Diabetes Type 1 hallmarks and aging acceleration. Genetic or dietary suppression of Insulin/IGF-like signaling (IIS) titrated Nrf2 activity to lower levels, largely normalized metabolic pathways signaling, and extended flies' lifespan. Thus, prolonged stress signaling by otherwise cytoprotective short-lived stress sensors perturbs IIS resulting in re-allocation of resources from growth and longevity to somatic preservation and stress tolerance. These findings provide a reasonable explanation of why most (if not all) cytoprotective stress sensors are short-lived proteins, and it also explains the build-in negative feedback loops (shown here for Nrf2); the low basal levels of these proteins, and why their suppressors were favored by evolution

GreekLex 2: a comprehensive lexical database with part-of-speech, syllabic, phonological, and stress information

Databases containing lexical properties on any given orthography are crucial for psycholinguistic research. In the last ten years, a number of lexical databases have been developed for Greek. However, these lack important part-of-speech information. Furthermore, the need for alternative procedures for calculating syllabic measurements and stress information, as well as combination of several metrics to investigate linguistic properties of the Greek language are highlighted. To address these issues, we present a new extensive lexical database of Modern Greek (GreekLex 2) with part-of-speech information for each word and accurate syllabification and orthographic information predictive of stress, as well as several measurements of word similarity and phonetic information. The addition of detailed statistical information about Greek part-of-speech, syllabification, and stress neighbourhood allowed novel analyses of stress distribution within different grammatical categories and syllabic lengths to be carried out. Results showed that the statistical preponderance of stress position on the pre-final syllable that is reported for Greek language is dependent upon grammatical category. Additionally, analyses showed that a proportion higher than 90% of the tokens in the database would be stressed correctly solely by relying on stress neighbourhood information. The database and the scripts for orthographic and phonological syllabification as well as phonetic transcription are available at http://www.psychology.nottingham.ac.uk/greeklex/

Aestivation motifs explain hypertension and muscle mass loss in mice with psoriatic skin barrier defect

AIM: Recent evidence suggests that arterial hypertension could be alternatively explained as a physiological adaptation response to water shortage, termed aestivation, which relies on complex multi-organ metabolic adjustments to prevent dehydration. Here we tested the hypothesis that chronic water loss across diseased skin leads to similar adaptive water conservation responses as observed in experimental renal failure or high salt diet. METHODS: We studied mice with keratinocyte-specific overexpression of IL-17A which develop severe psoriasis-like skin disease. We measured transepidermal water loss and solute and water excretion in the urine. We quantified glomerular filtration rate (GFR) by intravital microscopy, and energy and nitrogen pathways by metabolomics. We measured skin blood flow and transepidermal water loss (TEWL) in conjunction with renal resistive indices and arterial blood pressure. RESULTS: Psoriatic animals lost large amounts of water across their defective cutaneous epithelial barrier. Metabolic adaptive water conservation included mobilization of nitrogen and energy from muscle to increase organic osmolyte production, solute-driven maximal anti-diuresis at normal GFR, increased metanephrine and angiotensin 2 levels, and cutaneous vasoconstriction to limit TEWL. Heat exposure led to cutaneous vasodilation and blood pressure normalization without parallel changes in renal resistive index, albeit at the expense of further increased TEWL. CONCLUSION: Severe cutaneous water loss predisposes psoriatic mice to lethal dehydration. In response to this dehydration stress, the mice activate aestivation-like water conservation motifs to maintain their body hydration status. The circulatory water conservation response explains their arterial hypertension. The nitrogen-dependency of the metabolic water conservation response explains their catabolic muscle wasting

NMR studies of inborn errors of metabolism

Inborn errors of metabolism (IEM) are genetic inherited diseases resulting in an abnormal metabolic phenotype. NMR spectroscopy captures the metabolic profile in a rapid and extremely highly reproducible and holistic way, detecting both known and unknown metabolites simultaneously over an extended concentration range. Application of NMR as a method for IEM diagnosis is discussed in terms of body fluid sample collection and treatment, detection methods, and data treatment. Such diagnoses then allow targeted therapies or dietary interventions. Examples are provided for selected cases and novel applications. © 2015 John Wiley & Sons, Ltd

NMR-based metabolic profiling procedures for biofluids and cell and tissue extracts

Metabolomic studies offer a wealth of information on cells, tissues, and biofluids. The phenotype representation through the metabolic profiling is a valuable tool for direct diagnosis, therapeutic strategies, and system’s biology studies. Nuclear magnetic resonance (NMR) spectroscopy provides a nondestructive and extremely reproducible method allowing simultaneous detection of a large number of known and unknown chemical substances. Sample collection and preparation and experimental conditions are critical for the reliability of the subsequent analysis. The pre-analytical phase is decisive as it could generate biased spectral data misleading the following analysis. The formulation of standard operating procedures is thus of crucial importance in order to access meaningful samples and results. In this protocol, we provide standardized operations and routine procedures from sample preparation to determine the measurement details for the acquisition of NMR spectra highlighting major methodological issues. © 2018, Springer Science+Business Media, LLC, part of Springer Nature

NMR Studies of Inborn Errors of Metabolism

Proteomic

From bench to bedside, via desktop. Recent advances in the application of cutting-edge in silico tools in the research of drugs targeting bromodomain modules

The discipline of drug discovery has greatly benefited by computational tools and in silico algorithms aiming at rationalization of many related processes, from the stage of early hit identification to the preclinical phases of drug candidate validation. The various methodologies referred to as molecular modeling tools span a broad spectrum of applications, from straightforward approaches such as virtual screening of compound libraries to more advanced techniques involving the precise estimation of free energy upon binding of the candidate drug to its macromolecular target. To this end, we report an overview of specific studies where implementation of such sophisticated modeling algorithms has shown to be indispensable for addressing challenging systems and biological questions otherwise difficult to answer. We focus our attention on the emerging field of bromodomain inhibitors. Bromodomains are small modules involved in epigenetic signaling and currently comprise high-priority targets for developing both drug candidates and chemical probes for basic biomedical research. We attempt a critical presentation of selected cases utilizing cutting-edge in silico methodologies, with our main emphasis being on absolute or relative free energy simulations, on implementation of quantum-mechanics level calculations and on characterization of solvent thermodynamics. We discuss the advantages and strengths as well as the drawbacks and weaknesses of computational tools utilized in those works and we attempt to comment on specific issues related to their integration into the regular medicinal chemistry practice. Our conclusion is that while such methods indeed represent highly promising resources for further advancing the discipline, their application is not always trivial. © 2018 Elsevier Inc

Conformational analysis of C-disaccharides using molecular mechanics calculations

Relaxed-residue energy maps based on the MM3 force field were computed for the methyl glycosides of eight C-linked D-glucosyl disaccharides: the two-bond axial-equatorial linked disaccharides β-kojibioside [(1→2)α-], β-nigeroside [(1→3)α-] and β-maltose [(1→4)α-], the two-bond equatorial-equatorial linked disaccharides β-sophoroside [(1→2)β-], β-laminarabioside [(1→3)β-], β-cellobioside [(1→4)β-] and the three-bond-linked (1→6) disacharides C-isomaltoside and C-gentiobioside. Optimized structures were calculated on a 20° grid spacing of the torsional angles about the C-glycosidic bonds and the final isoenergy surfaces were based on 11664 conformations, for the two-bond-linked disaccharides and 69984 conformations for the three-bond-linked disaccharides. Boltzmann-weighted 3J coupling constants were calculated and compared to the experimental values. They are satisfactory except for maltose where hydrogen bonds cause an over-estimation of the energy differences between the conformers. The energy maps are similar to maps of the corresponding O-disaccharides, but there are differences in the locations and the relative energies of the minima. The preferred conformations of the C-glycosidic bonds are as if they were conforming to the exo-anomeric effect but are closer to staggered conformations than shown by the MM3 results for the O-linkages

Application of metabonomics on an experimental model of fibrosis and cirrhosis induced by thioacetamide in rats

Metabonomics has already been used to discriminate different pathological states in biological fields. The metabolic profiles of chronic experimental fibrosis and cirrhosis induction in rats were investigated using 1H NMR spectroscopy of liver extracts and serum combined with pattern recognition techniques. Rats were continuously administered with thioacetamide (TAA) in the drinking water (300 mg TAA/L), and sacrificed on 1st, 2nd, and 3rd month of treatment. 1H NMR spectra of aqueous and lipid liver extracts, together with serum were subjected to Principal Component Analysis (PCA). Liver portions were also subjected to histopathological examination and biochemical determination of malondialdehyde (MDA). Liver fibrosis and cirrhosis were progressively induced in TAA-treated rats, verified by the histopathological examination and the alterations of MDA levels. TAA administration revealed a number of changes in the 1H NMR spectra compared to control samples. The performance of PCA in liver extracts and serum, discriminated the control samples from the fibrotic and cirrhotic ones. Metabolic alterations revealed in NMR spectra during experimental liver fibrosis and cirrhosis induction, characterize the stage of fibrosis and could be illustrated by subsequent PCA of the spectra. Additionally, the PCA plots of the serum samples presented marked clustering during fibrosis progression and could be extended in clinical diagnosis for the management of cirrhotic patients. © 2006 Elsevier Inc. All rights reserved