Jianghua Feng

Understanding the metabolic fate and assessing the biosafety of MnO nanoparticles by metabonomic analysis

Recently, some types of MnO nanoparticle (Mn-NP) with favorable imaging capacity have been developed to improve the biocompatible profile of the existing Mn-based MRI contrast agent Mn-DPDP; however, the overall bio-effects and potential toxicity remain largely unknown. In this study, (1)H NMR-based metabolic profiling, integrated with traditional biochemical analysis and histopathological examinations, was used to investigate the absorption, distribution, metabolism, excretion and toxicity of Mn-NPs as candidates for MRI contrast agent. The metabolic responses in biofluids (plasma and urine) and tissues (liver, spleen, kidney, lung and brain) from rats could be divided into four classes following Mn-NP administration: Mn biodistribution-dependent, time-dependent, dose-dependent and complicated metabolic variations. The variations of these metabolites involved in lipid, energy, amino acid and other nutrient metabolism, which disclosed the metabolic fate and biological effects of Mn-NPs in rats. The changes of metabolic profile implied that the disturbance and impairment of biological functions induced by Mn-NP exposure were correlated with the particle size and the surface chemistry of nanoparticles. Integration of metabonomic technology with traditional methods provides a promising tool to understand the toxicological behavior of biomedical nanomaterials and will result in informed decision-making during drug development.

A high-resolution 2D J -resolved NMR detection technique for metabolite analyses of biological samples

NMR spectroscopy is a commonly used technique for metabolite analyses. Due to the observed macroscopic magnetic susceptibility in biological tissues, current NMR acquisitions in measurements of biological tissues are generally performed on tissue extracts using liquid NMR or on tissues using magic-angle spinning techniques. In this study, we propose an NMR method to achieve high-resolution J-resolved information for metabolite analyses directly from intact biological samples. A dramatic improvement in spectral resolution is evident in our contrastive demonstrations on a sample of pig brain tissue. Metabolite analyses for a postmortem fish from fresh to decayed statuses are presented to further reveal the capability of the proposed method. This method is a previously-unreported high-resolution 2D J-resolved spectroscopy for biological applications without specialised hardware requirements or complicated sample pretreatments. It provides a significant contribution to metabolite analyses of biological samples, and may be potentially applicable to in vivo samples. Furthermore, this method also can be applied to measurements of semisolid and viscous samples.

Metabolomic Profilings of Urine and Serum from High Fat-Fed Rats via 1H NMR Spectroscopy and Pattern Recognition

Abstract1H NMR spectroscopy in combination with multivariate statistical analysis was applied to explore the metabolic variability in urine and serum of high fat-fed rats relative to normal chow-fed ones. Metabolites contributing to intergroup discrimination identified by partial least squares discriminant analysis include 3-hydroxybutyrate, glutamate, glutamine, citrate, choline, hippurate, alanine, lactate, creatinine, taurine, acetate, etc. The aging effect along with long-term feeding was delineated with metabolic trajectory in principal component analysis score plot and age-related differences on metabolic profiling under different dietary intervention were recognised. The identified metabolites responsible for obesity were all imported into a web tool for network-based interpretation of compound lists to interpret their functional context, molecular mechanisms and disturbed signalling pathway globally and systematically. The results are useful for interpreting the pathology of obesity and further probing into the relationship between dietary-induced obesity and type 2 diabetes mellitus.

Origin Identification and Quantitative Analysis of Honeys by Nuclear Magnetic Resonance and Chemometric Techniques

The combination of 1H NMR spectroscopy and multivariate statistical analysis has become a promising method for the discrimination of food origins. In this paper, this method has been successfully employed to analyze 70 Chinese honey samples from eight botanic origins, three geographical origins, and five production dates. Thirty-three components in honey samples were detected and identified from their 1H NMR spectra, and 20 of them were accurately quantified by comparing their integral area with that of internal standards with relaxation time correction. Nontargeted principal component analysis (PCA) has been applied to distinguish the honeys from different botanical and geographical origins. The variations of components in the honeys, including saccharides and all kind of amino and organic carboxylic acids, confirmed their clustering according to their origins in PCA scores plots. Orthogonal partial least squares discriminant analysis (OPLS-DA) based on the NMR data for the different pairwise honey samples allows to identify the compositional variations contributed to geographical discrimination and storage time. Hence, NMR spectroscopy coupled with chemometric techniques offers an efficient tool for quality control of honey, and it could further serve to the classification, qualitative and quantitative control of other foods.

Metabolic responses of Haliotis diversicolor to Vibrio parahaemolyticus infection

ABSTRACT Vibrio parahemolyticus is a devastating bacterial pathogen that often causes outbreak of vibriosis in abalone Haliotis diversicolor. Elucidation of metabolic mechanisms of abalones in responding to V. parahemolyticus infection is essential for controlling the epidemic. In this work, 1H NMR‐based metabolomic techniques along with correlation and network analyses are used to investigate characteristic metabolites, as well as corresponding disturbed pathways in hepatopancreas and gill of H. diversicolor after V. parahemolyticus infection for 48 h. Results indicate that obvious gender‐ and tissue‐specific metabolic responses are induced. Metabolic responses in female abalones are more clearly observed than those in males, which are primarily manifested in the accumulation of branched‐chain amino acids and the depletion of organic osmolytes (homarine, betaine and taurine) in the infected gills of female abalones, as well as in the depletion of glutamate, branched‐chain and aromatic amino acids in the infected hepatopancreases of female abalones. Moreover, based on major metabolic functions of the characteristic metabolites, we have found that V. parahemolyticus infection not only cause the disturbance in energy metabolism, nucleotide metabolism and osmotic balance, but also induce oxidative stress, immune stress and neurotoxic effect in different tissues with various mechanisms. Our study provides details of metabolic responses of abalones to V. parahemolyticus infection and will shed light on biochemical defence mechanisms of male and female hosts against pathogen infection. HIGHLIGHTSMetabolic profiles of Haliotis diversicolor to Vibrio parahemolyticus were studied.Obvious gender‐ & tissue‐specific responses are found in gill and hepatopancreas.Vibrio infection disturbs energy and nucleotide metabolisms and osmotic regulation.Oxidative and immune stresses are induced by vibrio infection.This study helps to understand the mechanisms of immune defense of abalone.

Metabolomic responses of Haliotis diversicolor to organotin compounds

Organotin compounds, especially tributyltin (TBT) and triphenyltin (TPT), are a group of hazardous pollutants in marine environments. Haliotis diversicolor is an important marine model organism for environmental science. In this study, 1H NMR spectroscopy together with pattern recognition methods was used to investigate the responses of hepatopancreas and gill of Haliotis diversicolor to TBT and TPT exposure. It was found that obvious gender-, tissue- and compound-specific metabolomic alterations were induced after a 28-day exposure. TBT and TPT exposure not only caused the disturbance in energy metabolism and osmotic balance in hepatopancreas and gill tissues with different mechanisms, but also induced oxidative stresses. These metabolic alterations were highlighted in the accumulation of aspartate, uridine diphosphate-N-acetylglucosamine, uridine diphosphate glucose, guanosine and the depletion of leucine, isoleucine, valine, malonate, homarine, trigonelline in all exposure gills, as well as in the depletion of ATP, AMP, betaine in male exposure gills and pantothenate in male exposure hepatopancreases. The significant decreased aromatic amino acids (AAAs), lysine and glutamate in gills and increased betaine in hepatopancreases for TPT exposure together with increased glutamate and decreased betaine in gills and increased glutamate and glycine in hepatopancreases for TBT exposure demonstrated their specific metabolic characteristics. Among these characteristic metabolites, AAAs, lysine and glutamate in the gill as well as pantothenate in the hepatopancreas might be identified as potential biomarkers for TPT or TBT exposure in Haliotis diversicolor. The results provide a useful insight into the toxicological mechanisms of organotin compounds on Haliotis diversicolor.

The relations between metabolic variations and genetic evolution of different species.

Metabonomics has been applied in many bio-related scientific fields. Nevertheless, some animal research works are shown to fail when they are extended to humans. Therefore, it is essential to figure out suitable animal modeling to mimic human metabolism so that animal findings can serve humans. In this study, two kinds of commonly selected body fluids, serum and urine, from humans and various experimental animals were characterized by integration of nuclear magnetic resonance (NMR) spectroscopy with multivariate statistical analysis to identify the interspecies metabolic differences and similarities at a baseline physiological status. Our results highlight that the dairy cow and pig may be an optimal choice for transportation and biodistribution studies of drugs and that the Kunming (KM) mouse model may be the most effective for excretion studies of drugs, whereas the Sprague-Dawley (SD) rat could be the most suitable candidate for animal modeling under overall considerations. The biochemical pathways analyses further provide an interconnection between genetic evolution and metabolic variations, where species evolution most strongly affects microbial biodiversity and, consequently, has effects on the species-specific biological substances of biosynthesis and corresponding biological activities. Knowledge of the metabolic effects from species difference will enable the construction of better models for disease diagnosis, drug metabolism, and toxicology research.

Metabonomic changes from pancreatic intraepithelial neoplasia to pancreatic ductal adenocarcinoma in tissues from rats

Pancreatic ductal adenocarcinoma (PDAC) is one of the most malignant tumors and is difficult to diagnose in the early phase. This study was aimed at obtaining the metabolic profiles and characteristic metabolites of pancreatic intraepithelial neoplasia (PanIN) and PDAC tissues from Sprague–Dawley (SD) rats to establish metabonomic methods used in the early diagnosis of PDAC. In the present study, the animal models were established by embedding 7,12‐dimethylbenzanthracene (DMBA) in the pancreas of SD rats to obtain PanIN and PDAC tissues. After the preprocessing of tissues, 1H nuclear magnetic resonance (NMR) spectroscopy combined with multivariate and univariate statistical analysis was applied to identify the potential metabolic signatures and the corresponding metabolic pathways. Pattern recognition models were successfully established and differential metabolites, including glucose, amino acids, carboxylic acids and coenzymes, were screened out. Compared with the control, the trends in the variation of several metabolites were similar in both PanIN and PDAC. Kynurenate and methionine levels were elevated in PanIN but decreased in PDAC, thus, could served as biomarkers to distinguish PanIN from PDAC. Our results suggest that NMR‐based techniques combined with multivariate statistical analysis can distinguish the metabolic differences among PanIN, PDAC and normal tissues, and, therefore, present a promising approach for physiopathologic metabolism investigations and early diagnoses of PDAC.

Identification and causes of metabonomic difference between orthotopic and subcutaneous xenograft of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal tumors. However, the methodological differences between orthotopic and subcutaneous xenograft (OX and SX) models will cause confusion in understanding its pathological mechanism and clinical relevance. In this study, SX and OX models were established by implanting Panc-1 and BxPC-3 cell strains under skin and on the pancreas of mice, respectively. The tumor tissue and serum samples were collected for1H NMR spectroscopy followed by univariate and multivariate statistical analyses. As results, no obvious metabonomic difference was demonstrated in serum between the two models, however, the model- and cell strain-specific metabonomic differences were observed in tumor tissues. According to the KEGG analysis, ABC transporters, glycerophospholipid metabolism, purine metabolism and central carbon metabolism were identified to be the most significant components involved in metabonomic differences. Considering the methodological discrepancy in SX and OX models, such differences should be contributed to tumor microenvironment. In general, SX are not equivalent to OX models at molecular level. Subcutaneous transplantation displayed its inherent limitations though it offered a simple, inexpensive, reproducible and quantifiable advantage. And orthotopic transplantation may be favorable to simulate PDAC in patients due to its similar pathogenesis to human pancreatic cancer.Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal tumors. However, the methodological differences between orthotopic and subcutaneous xenograft (OX and SX) models will cause confusion in understanding its pathological mechanism and clinical relevance. In this study, SX and OX models were established by implanting Panc-1 and BxPC-3 cell strains under skin and on the pancreas of mice, respectively. The tumor tissue and serum samples were collected for1H NMR spectroscopy followed by univariate and multivariate statistical analyses. As results, no obvious metabonomic difference was demonstrated in serum between the two models, however, the model- and cell strain-specific metabonomic differences were observed in tumor tissues. According to the KEGG analysis, ABC transporters, glycerophospholipid metabolism, purine metabolism and central carbon metabolism were identified to be the most significant components involved in metabonomic differences. Considering the methodological discrepancy in SX and OX models, such differences should be contributed to tumor microenvironment. In general, SX are not equivalent to OX models at molecular level. Subcutaneous transplantation displayed its inherent limitations though it offered a simple, inexpensive, reproducible and quantifiable advantage. And orthotopic transplantation may be favorable to simulate PDAC in patients due to its similar pathogenesis to human pancreatic cancer.

Metabolic Effect of Dietary Taurine Supplementation on Nile Tilapia (Oreochromis nilotictus) Evaluated by NMR-Based Metabolomics

Taurine is indispensable in aquatic diets that are based solely on plant protein, and it promotes growth of many fish species. However, the physiological and metabolome effects of taurine on fish have not been well described. In this study, 1H NMR-based metabolomics approaches were applied to investigate the metabolite variations in Nile tilapia (Oreochromis nilotictus) muscle in order to visualize the metabolic trajectory and reveal the possible mechanisms of metabolic effects of dietary taurine supplementation on tilapia growth. After extraction using aqueous and organic solvents, 19 taurine-induced metabolic changes were evaluated in our study. The metabolic changes were characterized by differences in carbohydrate, amino acid, lipid, and nucleotide contents. The results indicate that taurine supplementation could significantly regulate the physiological state of fish and promote growth and development. These results provide a basis for understanding the mechanism of dietary taurine supplementation in fish feeding. 1H NMR spectroscopy, coupled with multivariate pattern recognition technologies, is an efficient and useful tool to map the fish metabolome and identify metabolic responses to different dietary nutrients in aquaculture.