Update on the fluorometric measurement of enzymatic activities for Lysosomal Storage Disorder detection: The example of MPS VI

Lysosomal Storage Disorders (LSD) are rare diseases that as a whole havea combined incidence ranging from 1:1500 to 1:7000 live births. One of suchdiseases is Mucopolysaccharidosis VI (MPS VI), or Maroteaux Lamy Syndrome.MPS VI patients undergo devastating and irreversible skeletal alterations andmultisystemic failure as from early childhood due to reduced Arylsulfatse B(ARSB) enzyme activity.Reaching a final diagnosis is not always a short cut path, but rather a yearslongbattle against uncertainty and unnecessary medical interventions. Ouraim is to contribute from the bench table with different approaches that couldserve as alternatives to pre-existing assays for screening and diagnosing MPSVI and other LSD.The present work is based on our research article authored by Franco etal.1 where we studied the effect of blood-derived hemoglobin, and other bloodcomponents, on the fluorescence of 4-Methylumbelliferone when measuringARSB enzyme activity from dried blood spot (DBS) samples.Our experience indicates that to date there are plenty of differentapproaches for measuring ARSB enzyme activity, although the sample typerequired or the assay in itself often make them more adaptable for either highthroughput screening or small scale diagnostics.As a whole, the fluorometric determinations seem to be the mostaccessible to low budget laboratories with equally valuable performancesas a sophisticated mass spectrometry analysis for this disease. Furthermore,the DBS serves as an attractive sample type for screening the disease in largepopulations.Fil: Franco, Paula Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas ; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Departamento de Quimica Biologica. Cátedra de Química Biológica Patológica; ArgentinaFil: Adamo, Ana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas ; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Departamento de Quimica Biologica. Cátedra de Química Biológica Patológica; ArgentinaFil: Mathieu, Patricia Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas ; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Departamento de Quimica Biologica. Cátedra de Química Biológica Patológica; ArgentinaFil: Perez, Maria Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas ; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Departamento de Quimica Biologica. Cátedra de Química Biológica Patológica; ArgentinaFil: Setton, Clara Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas ; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Departamento de Quimica Biologica. Cátedra de Química Biológica Patológica; ArgentinaFil: Silvestroff, Lucas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas ; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Departamento de Quimica Biologica. Cátedra de Química Biológica Patológica; Argentin

Study of incompatibility of ammonium nitrate and its mechanism of decomposition by theoretical approach

International audienceThe dramatic accident involving ammonium nitrate (AN) that took place at Toulouse in September 2001 has once again focused attention to the complex hazards pertaining to this chemical. Despite the significant efforts made to increase AN safety over the whole supply chain, we are still facing insufficient knowledge of the actual mechanisms of ammonium nitrate decomposition that may take place in abnormal situations. The paper proposes a theoretical study of chemical incompatibilities of ammonium nitrate with the aim to better understand the driving mechanism(s) through which the explosive reaction takes place with the neat or contaminated substance, to identify what molecules can realistically be generated from this process and to estimate the energy involved. The results, coupled with experimental data, should allow a better understanding of ammonium nitrate hazard profile

Development of a new QSPR based tool to predict explosibility properties of chemical substances within the framework of REACH and GHS

International audienceThe new European régulation of Chemicals named REACH (for "Registration, Evaluation and Authorization of Chemicals") turned out in the practical registration phase in December 2008. It requires the new assessment of hazard properties for up to 140000 substances. In this context, the development of alternative prédictive methods for assessing hazardous properties of chemical substances is promoted in REACH and in the related new European classification System of substances CLP (Classification, Labelling and Packaging of chemical substances and mixtures

Prediction of physico-chemical properties for REACH based on QSPR models

International audienceQuantitative Structure Property Relationship models have been developed for the prediction of flash points of two families of organic compounds selected in the PREDIMOL French Project: amines and organic peroxides. If the model dedicated to amines respected all OECD validation principles with excellent performances in predictivity, the one dedicated to organic peroxides was not validated on an external validation set, due to the low number of available data, but already presented high performances in fitting and robustness. This work highlighted the need of gathering experimental data, as in progress in the PREDIMOL project, to achieve validated reliable models that could be used in a regulatory framework, like REACH. Such models are expected to be submitted to the European Joint Research Comity (JRC) and to existing tools (like the OECD ECHA QSAR Toolbox) to be available for use by industrials and regulatory instances

Development of a QSPR model for predicting thermal stabilities of nitroaromatic compounds taking into account their decomposition mechanisms

International audienceThe molecular structures of 77 nitroaromatic compounds have been correlated to their thermal stabilities by combining the quantitative structure-property relationship (QSPR) method with density functional theory (DFT). More than 300 descriptors (constitutional, topological, geometrical and quantum chemical) have been calculated, and multilinear regressions have been performed to find accurate quantitative relationships with experimental heats of decomposition (deltaH). In particular, this work demonstrates the importance of accounting for chemical mechanisms during the selection of an adequate experimental data set. A reliable QSPR model that presents a strong correlation with experimental data for both the training and the validation molecular sets (R 2 = 0.90 and 0.84, respectively) was developed for non-ortho-substituted nitroaromatic compounds. Moreover, its applicability domain was determined, and the model's predictivity reached 0.86 within this applicability domain. To our knowledge, this work has produced the first QSPR model, developed according to the OECD principles of regulatory acceptability, for predicting the thermal stabilities of energetic compounds

Dietary Anthocyanins Mitigate High-Fat Diet-Induced Hippocampal Inflammation in Mice

BackgroundObesity and consumption of high-fat diets (HFD) are associated with intestinal permeabilization and increased paracellular transport of endotoxins, which can promote neuroinflammation. Inflammation can affect the hypothalamic pituitary adrenal (HPA) axis, which controls responses to stress and downregulates the brain-derived neurotrophic factor (BDNF), which can promote anxiety and depression, conditions frequently found in obesity. We previously showed that consumption of anthocyanins (AC) mitigate HFD-induced insulin resistance, intestinal permeability, and inflammation.ObjectivesThis study investigated if a dietary supplementation with a cyanidin- and delphinidin-rich extract (CDRE) could counteract HFD/obesity-induced hippocampal inflammation in mice.MethodsC57BL/6J male mice were fed for 14 wk on one of the following diets: 1) a control diet containing 10% total calories from fat (C), 2) a control diet supplemented with 40 mg AC/kg body weight (BW) (CAC), 3) a HFD containing 60% total calories from fat (lard) (HF), or 4) the HFD supplemented with 2, 20, or 40 mg AC/kg BW (HFA2, HFA20, and HFA40, respectively). In plasma and in the hippocampus, parameters of neuroinflammation and the underlying cause (endotoxemia) and consequences (alterations to the HPA and BDNF downregulation) were measured.ResultsConsumption of the HFD caused endotoxemia. Accordingly, hippocampal Tlr4 mRNA levels were 110% higher in the HF group, which were both prevented by CDRE supplementation. Consumption of the HFD also caused: 1) microgliosis and increased expression of genes involved in neuroinflammation, that is, Iba-1, Nox4, Tnfα, and Il-1β, 2) alterations of HPA axis regulation, that is, with low expression of mineralocorticoid (MR) and glucocorticoid (GR) receptors; and 3) decreased Bdnf expression. Supplementation of HFD-fed mice with CDRE mitigated neuroinflammation, microgliosis, and MR and BDNF decreases.ConclusionsCDRE supplementation mitigates the negative effects associated with HFD consumption and obesity in mouse hippocampus, in part by decreasing inflammation, improving glucocorticoid metabolism, and upregulating BDNF

On the prediction of thermal stability of nitroaromatic compounds using quantum chemical calculations

International audienceThis work presents a new approach to predict thermal stability of nitroaromatic compounds based on quantum chemical calculations and on quantitative structure-property relationship (QSPR) methods. The data set consists of 22 nitroaromatic compounds of known decomposition enthalpy (taken as a macroscopic property related to explosibility) obtained from differential scanning calorimetry. Geometric, electronic and energetic descriptors have been selected and computed using density functional theory (DFT) calculation to describe the 22 molecules. First approach consisted in looking at their linear correlations with the experimental decomposition enthalpy. Molecular weight, electrophilicity index, electron affinity and oxygen balance appeared as the most correlated descriptors (respectively R2 = 0.76, 0.75, 0.71 and 0.64). Then multilinear regression was computed with these descriptors. The obtained model is a six-parameter equation containing descriptors all issued from quantum chemical calculations. The prediction is satisfactory with a correlation coefficient R2 of 0.91 and a predictivity coefficient R2(cv) of 0.84 using a cross validation method

Investigating Social Preferences in a High Fission-Fusion Society of Black and White Ruffed Lemur (Varecia Variegata)

Wild lemur primates were tested for social preferences across behaviors. Study found highly conservative social preferences that were very consistent across all behavioral states, despite high fission fusion traits common of lemur groups. This finding lays the foundation for using nearest-neighbor as a proxy of social preference for future endeavors

A mechanistic and experimental study of the diethyl ether oxidation

International audienceThis work presents the results of the theoretical investigations on autoxidation process of diethyl ether (DEE), a chemical largely used as solvent in laboratories and considered to be responsible for various accidents. Based on Density Functional Theory (DFT) calculations, the aims of this study were the identification of all the most probable reaction paths involved in DEE oxidation (at ambient temperature and under conditions that reflect normal storage conditions) and the characterization of products and all potential hazardous intermediates, such as peroxides. Results indicate that industrial hazards could be related to hydroperoxide formation and accumulation during the chain propagation step. A detailed kinetics model of DEE oxidation in the gas phase was then developed from all energetic and kinetics parameters collected during the mechanistic study. Outputs of the kinetics model, in terms of time of evolution of product concentrations, have been then compared with the experimentally measured concentration of products (notably hydroperoxides) issued from tests on DEE oxidation conducted under accelerated conditions with autoclaves

Hexameric procyanidins inhibit colorectal cancer cell growth through both redox and non-redox regulation of the epidermal growth factor signaling pathway

Dietary proanthocyanidins (PAC) consumption is associated with a decreased risk for colorectal cancer (CRC). Dysregulation of the epidermal growth factor (EGF) receptor (EGFR) signaling pathway is frequent in human cancers, including CRC. We previously showed that hexameric PAC (Hex) exert anti-proliferative and pro-apoptotic actions in human CRC cells. This work investigated if Hex could exert anti-CRC effects through its capacity to regulate the EGFR pathway. In proliferating Caco-2 cells, Hex acted attenuating EGF-induced EGFR dimerization and NADPH oxidase-dependent phosphorylation at Tyr 1068, decreasing EGFR location at lipid rafts, and inhibiting the downstream activation of pro-proliferative and anti-apoptotic pathways, i.e. Raf/MEK/ERK1/2 and PI3K/Akt. Hex also promoted EGFR internalization both in the absence and presence of EGF. While Hex decreased EGFR phosphorylation at Tyr 1068, it increased EGFR Tyr 1045 phosphorylation. The latter provides a docking site for the ubiquitin ligase c-Cbl and promotes EGFR degradation by lysosomes. Importantly, Hex acted synergistically with the EGFR-targeted chemotherapeutic drug Erlotinib, both in their capacity to decrease EGFR phosphorylation and inhibit cell growth. Thus, dietary PAC could exert anti-CRC actions by modulating, through both redox- and non-redox-regulated mechanisms, the EGFR pro-oncogenic signaling pathway. Additionally, Hex could also potentiate the actions of EGFR-targeted drugs.Fil: Daveri, Elena. University of California at Davis; Estados UnidosFil: Adamo, Ana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Alfine, Eugenia. University of California at Davis; Estados UnidosFil: Zhu, Wei. University of California at Davis; Estados UnidosFil: Oteiza, Patricia Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; Argentin