Identification of rat targets of anti-soluble liver antigen autoantibodies by serologic proteome analysis

BACKGROUND: Anti-soluble liver antigen (SLA) autoantibodies are specific for autoimmune hepatitis type 1 and are the only immunologic marker found in 15-20% of hepatitis cases previously considered cryptogenic. Anti-SLA antibodies react with the 100 000g supernatant from rat liver homogenate, but the molecular targets remain controversial. METHODS: We characterized anti-SLA targets by one- and two-dimensional immunoblotting analysis. The recognized proteins were identified by peptide mass fingerprint analysis after matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. RESULTS: Three proteins of 35 kDa and pI 6.0, 50 kDa and pI between 6.0 and 6.5, and 58 kDa and pI between 6.5 and 7.0 were stained more intensely by anti-SLA positive-sera than by control sera. After in-gel tryptic digestion, MALDI-TOF analysis of the generated peptides enabled the clear identification of N-hydroxyarylamine sulfotransferase, isoforms of alpha-enolase, and isoforms of catalase. CONCLUSIONS: Possible antigens for anti-SLA antibodies include a sulfotransferase, alpha-enolase(s), and catalase(s). Two-dimensional electrophoresis combined with mass spectrometry offers a versatile tool to identify molecular targets of autoantibodies and thus to improve diagnostic tools and the understanding of the immune process.     

Metabolomics-driven identification of perturbations in amino acid and sphingolipid metabolism as therapeutic targets in a rat model of anorexia nervosa disease using chemometric analysis and a multivariate analysis platform

It is important to explore novel therapeutic targets and develop an effective strategy for the treatment of anorexia nervosa. In this work, serum samples were analyzed using ultra-performance liquid chromatography coupled with quadrupole time-of flight mass spectrometry (UPLC/Q-TOF MS) coupled with chemometric analysis and multivariate analysis to obtain the metabolites and their corresponding pathways. In addition, knock-in and knock-down of the key enzyme in vivo was performed to verify the reliability of the obtained metabolic pathway, which is closely associated with the anorexia nervosa pathomechanism and the potential targets. There were significant differences in the biochemical parameters between the model group and the control group. A total of 26 potential biomarkers were identified to resolve the difference between the control and model rats, which were closely related to amino acid metabolism, sphingolipid metabolism, arachidonic acid metabolism, the citrate cycle, and so forth. According to the ingenuity pathway analysis, we further elucidated the relationship between the gene, protein, and metabolite alteration in anorexia nervosa, which are involved in cellular compromise, lipid metabolism, small molecule biochemistry, cell signaling, molecular transport, nucleic acid metabolism, cell morphology, cellular function and maintenance. Arginosuccinate synthetase (ASS) deficiency was accompanied by a significant downregulation of the β-endorphin and ghrelin in the animal models. The metabolites and pathways obtained using the metabolomics strategy may provide valuable information for the early treatment for anorexia nervosa.

It is important to explore novel therapeutic targets and develop an effective strategy for the treatment of anorexia nervosa.     

Vascular proteomic mapping in vivo

Summary.  Molecular targeting of drugs and imaging agents remain important yet elusive goals in modern medicine. Technological advancements in genomics and proteomics methods have detected differentially expressed genes and proteins, uncovering many new candidate targets in a wide array of diseases and tissues. However, methods to validate potential targets in vivo tend to be quite laborious so that the validation and testing phase has become rate-limiting in bringing treatments to the clinic. There is a critical need for integrated approaches combining state-of-the-art methodologies in proteomics and in vivo imaging to accelerate validation of newly discovered vascular targets for nanomedicines, drugs, imaging agents, and gene vectors. This paper is a review of vascular targeting and proteomics, and will present recent developments in proteomic imaging. A new in vivo organellar proteomic imaging platform will be discussed, which combines subcellular fractionation, mass spectrometry, bioinformatic database interrogation, monoclonal antibody technology and a battery of imaging modalities to rapidly discover and validate tissue-specific endothelial protein targets in vivo . Technological advancements are permitting large-scale proteomic mapping to be performed. New targets have been discovered that permit organ-specific targeting in vivo . Improvements in imaging are creating standards for validation of targets in vivo . Tumor imaging and radioimmunotherapy have also been improved through these efforts. Although we are moving towards a comprehensive mapping of the protein expression by the endothelium, much more needs to be done.     

Intact cell/intact spore mass spectrometry (IC/ISMS) on polymer-based,nano-coated disposable targets

Identification and differentiation of microorganisms has and still is a long arduous task, involving culturing of the organism in question on different growth media. This procedure, which is still commonly applied, is an established method, but takes a lot of time, up to several days or even longer. It has thus been a great achievement when other analytical tools like matrix-assisted laser desorption/ionization (MALDI) mass spectrometry were introduced for faster analysis based on the surface protein pattern. Differentiation and identification of human pathogens as well as plant/animal pathogens is of increasing importance in medical care (e.g. infection, sepsis, and antibiotics resistance), biotechnology, food sciences and detection of biological warfare agents. A distinction between microorganisms on the species and strain level was made by comparing peptide/protein profiles to patterns already stored in databases. These profiles and patterns were obtained from the surface of vegetative forms of microorganisms or even their spores by MALDI MS. Thus, an unknown sample can be compared against a database of known pathogens or microorganisms of interest.To benefit from newly available, metal-based disposable microscope-slide format MALDI targets that promise a clean and even surface at a fraction of the cost from full metal targets or MTP (microtiter plate) format targets, IC/ISMS analysis was performed on these and the data evaluated. Various types of bacteria as well as fungal spores were identified unambiguously on this disposable new type of metal nano-coated targets. The method even allowed differentiation between strains of the same species. The results were compared with those gained from using full metal standard targets and found to be equal or even better in several aspects, making the use of disposable MALDI targets a viable option for use in IC/ISMS, especially e.g. for large sample throughput and highly pathogenic species.     

Stable isotope-mass spectrometric measurements of molecular fluxes in vivo: emerging applications in drug development

Therapeutics require not only targets and chemical entities, but tools for measuring actions in vivo. Technologies for evaluating activities, filtering leads and predicting clinical response have lagged behind molecular discovery. 'Systems biology' has not provided systematic methods for predicting metabolic effects in complex systems. The flow of molecules through complex pathways, in contrast, reflects the connectivity relationships and emergent control features of fully assembled networks, but is a quantifiable therapeutic target. This strategy, which combines molecular specificity with intrinsic functional significance, requires different tools. Here, advances in critical pathway flux measurement utilizing stable isotopes and mass spectrometry are described. These include mass isotopomer analysis, heavy-water labeling techniques, secreted probes of intracellular processes, and analytic advances. Several fundamental advantages of kinetic measurements are demonstrated. Measurement of molecular fluxes represents a powerful addition to drug development technology.     

Microsatellites: perspectives and potentials of mass spectrometric analysis

Mass spectrometry is a powerful analytical tool in biotechnology. The 'soft' ionization and desorption technologies matrix-assisted laser desorption/ionization and electrospray ionization have enabled mass spectrometric analysis of large biomolecules, such as proteins and nucleic acid amplification products, and paved the way for mass spectrometry to become a leading technology in current genomics and proteomics efforts. Large-scale analysis of single nucleotide polymorphisms by mass spectrometry has been commercially established. This article reviews applications of mass spectrometry for microsatellite analysis. Features and capabilities of the two most prominent techniques, matrix assisted laser desorption/ionization and electrospray-ionization mass spectrometry, are compared and their potential to address the limitations of conventional microsatellite analysis based on comparison of gel electrophoretic mobilities is explored.     

The application of cassette dosing for pharmacokinetic screening in small-molecule cancer drug discovery

Pharmacokinetic evaluation is an essential component of drug discovery and should be conducted early in the process so that those compounds with the best chance of success are prioritized and progressed. However, pharmacokinetic analysis has become a serious bottleneck during the 'hit-to-lead' and lead optimization phases due to the availability of new targets and the large numbers of compounds resulting from advances in synthesis and screening technologies. Cassette dosing, which involves the simultaneous administration of several compounds to a single animal followed by rapid sample analysis by liquid chromatography/tandem mass spectrometry, was developed to increase the throughput of in vivo pharmacokinetic screening. Although cassette dosing is advantageous in terms of resources and throughput, there are possible complications associated with this approach, such as the potential for compound interactions. Following an overview of the cassette dosing literature, this article focuses on the application of the technique in anticancer drug discovery. Specific examples are discussed, including the evaluation of cassette dosing to assess pharmacokinetic properties in the development of cyclin-dependent kinase and heat shock protein 90 inhibitors. Subject to critical analysis and validation in each case, the use of cassette dosing is recommended in appropriate chemical series to enhance the efficiency of drug discovery and reduce animal usage.     

The birth and infancy of proteomic analysis in osteoarthritis research

The search for efficient strategies for preventing cartilage degradation in osteoarthritis is a key issue in rheumatology. Proteomic technologies may help to identify new targets for pharmacological intervention as well as to contribute toward the identification of diagnostic biological markers. Proteomic analysis of osteoarthritis can be performed at different levels, including the cartilage itself, biological fluids such as synovial fluid or serum, or cell culture systems that can be used to investigate the functions of chondrocytes. Early proteomic studies of osteoarthritis have typically involved two-dimensional electrophoresis or liquid chromatography coupled to mass spectrometry, as well as protein microarrays. In the future, differential proteomic analyses that involve recently developed and powerful technologies such as those utilizing isotope-coded affinity tags, stable isotope labeling by amino acids in cell culture, or surface-enhanced desorption/ ionization time-of-flight analysis, should substantially improve our knowledge of the pathophysiology of osteoarthritis through the identification of novel disease markers.     

Retracted Article: High performance liquid chromatography coupled with high resolution mass spectrometry-based characterization of lipidomic responses from rats with kidney injuries

Metabolism of lipids is essential for the regulation of a variety of key cellular functions. Recent advances in high performance liquid chromatography coupled with high resolution mass spectrometry have expanded our knowledge of lipid metabolism in diseases. Currently, sepsis is one of the most important public health problems all over the world, which is a serious systemic inflammatory syndrome leading to infection by various agents or trauma and subsequently to a multiple organ dysfunction response. However, little is known about the lipids affected by sepsis and their roles in kidney injuries. In this study, we present targeted and non-targeted lipidomics strategies to discover the lipid metabolism variation in serum in rats with sepsis-induced kidney injuries. Liquid chromatography (LC) coupled with mass spectrometry (MS) and multivariate data analysis were used to obtain the global lipid metabolic profiles. In addition, biochemical parameters and histopathological examination results for the kidney were analyzed to support the pathological changes during sepsis-induced kidney injury. The identification of ten proposed lipids and five relevant pathways will promote a better understanding of lipid profile alterations in kidney injury. The results suggested that lipid metabolism in sepsis-induced kidney injury had changed significantly and contribute by offering potential targets for clinical diagnosis and therapy in the future, which would be worth further studies to broaden the applications of high performance liquid chromatography coupled with high resolution mass spectrometry in the study of lipid metabolism.

In this study, we present targeted and non-targeted lipidomics strategies to discover the lipid metabolism variation in serum in rats with sepsis-induced kidney injuries.     

Retracted Article: A high-throughput metabolomics strategy for discovering the influence of differential metabolites and metabolic pathways of huaxian capsules on sepsis-associated Qi deficiency and blood stasis syndrome

High-throughput metabolomics can be used to investigate the therapeutic targets and metabolic mechanisms of traditional Chinese medicine (TCM) formulae, which have multiple targets in disease therapy, but it is a great challenge to explore their mechanism of action. Huaxian capsule (HXC) is a classical formula in TCM that has therapeutic effects on a sepsis-associated Qi deficiency and blood stasis syndrome (SQBS). However, its targets and metabolic mechanisms need more investigation. To investigate the therapeutic effects of HXC in the treatment of SQBS and elucidate the potential mechanism, we used a high-throughput metabolomics strategy based on the ultraperformance liquid chromatography/mass spectrometry combined with chemometrics to analyze and identify differential metabolites and pathways. The pathological examination of organs and biochemical indices was also performed to verify the successful establishment of the rat model and protective effects of HXC. Pathological symptoms and biochemical indicators of SQBS rats were reversed by the HXC treatment. A total of 24 potential biomarkers were identified to indicate the difference between the control and model groups; they were closely associated with ten metabolic pathways and regulated by the HXC administration. From the pathway analysis, we further understood the protective activity of HXC against SQBS, which affected amino acid metabolism, molecular transport, small molecule biochemistry and cell signaling as well as vitamin and mineral metabolism. In conclusion, HXC protects against SQBS by modulating the metabolic biomarkers and functional pathways.

High-throughput metabolomics can be used to investigate the therapeutic targets and metabolic mechanisms of traditional Chinese medicine formulae.     

Evaluation of methods for trace-element determination with emphasis on their usability in the clinical routine laboratory

Commonly used techniques for trace-element analysis in human biological material are flame atomic absorption spectrometry (FAAS), graphite furnace atomic absorption spectrometry (GFAAS), inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). Elements that form volatile hydrides, first of all mercury, are analysed by hydride generation techniques. In the absorption techniques the samples are vaporized into free, neutral atoms and illuminated by a light source that emits the atomic spectrum of the element under analysis. The absorbance gives a quantitative measure of the concentration of the element. ICP-AES and ICP-MS are multi-element techniques. In ICP-AES the atoms of the sample are excited by, for example, argon plasma at very high temperatures. The emitted light is directed to a detector, and the optical signals are processed to values for the concentrations of the elements. In ICP-MS a mass spectrometer separates and detects ions produced by the ICP, according to their mass-to-charge ratio. Dilution of biological fluids is commonly needed to reduce the effect of the matrix. Digestion using acids and microwave energy in closed vessels at elevated pressure is often used. Matrix and spectral interferences may cause problems. Precautions should be taken against trace-element contamination during collection, storage and processing of samples. For clinical problems requiring the analysis of only one or a few elements, the use of FAAS may be sufficient, unless the higher sensitivity of GFAAS is required. For screening of multiple elements, however, the ICP techniques are preferable.     

Evaluation of methods for trace‐element determination with emphasis on their usability in the clinical routine laboratory

Commonly used techniques for trace‐element analysis in human biological material are flame atomic absorption spectrometry (FAAS), graphite furnace atomic absorption spectrometry (GFAAS), inductively coupled plasma atomic emission spectrometry (ICP‐AES) and inductively coupled plasma mass spectrometry (ICP‐MS). Elements that form volatile hydrides, first of all mercury, are analysed by hydride generation techniques. In the absorption techniques the samples are vaporized into free, neutral atoms and illuminated by a light source that emits the atomic spectrum of the element under analysis. The absorbance gives a quantitative measure of the concentration of the element. ICP‐AES and ICP‐MS are multi‐element techniques. In ICP‐AES the atoms of the sample are excited by, for example, argon plasma at very high temperatures. The emitted light is directed to a detector, and the optical signals are processed to values for the concentrations of the elements. In ICP‐MS a mass spectrometer separates and detects ions produced by the ICP, according to their mass‐to‐charge ratio. Dilution of biological fluids is commonly needed to reduce the effect of the matrix. Digestion using acids and microwave energy in closed vessels at elevated pressure is often used. Matrix and spectral interferences may cause problems. Precautions should be taken against trace‐element contamination during collection, storage and processing of samples. For clinical problems requiring the analysis of only one or a few elements, the use of FAAS may be sufficient, unless the higher sensitivity of GFAAS is required. For screening of multiple elements, however, the ICP techniques are preferable.     

A method to identify RNA A-to-I editing targets using I-specific cleavage and exon array analysis

RNA A-to-I editing is the most common single-base editing in the animal kingdom. Dysregulations of RNA A-to-I editing are associated with developmental defects in mouse and human diseases. Mouse knockout models deficient in ADAR activities show lethal phenotypes associated with defects in nervous system, failure of hematopoiesis and reduced tolerance to stress. While several methods of identifying RNA A-to-I editing sites are currently available, most of the critical editing targets responsible for the important biological functions of ADARs remain unknown. Here we report a method to systematically analyze RNA A-to-I editing targets by combining I-specific cleavage and exon array analysis. Our results show that I-specific cleavage on editing sites causes more than twofold signal reductions in edited exons of known targets such as Gria2, Htr2c, Gabra3 and Cyfip2 in mice. This method provides an experimental approach for genome-wide analysis of RNA A-to-I editing targets with exon-level resolution. We believe this method will help expedite inquiry into the roles of RNA A-to-I editing in various biological processes and diseases.     

基于网络药理学探讨肝积汤治疗肝癌的分子机制

目的 探讨基于网络药理学的肝积汤活性成分、治疗靶点及分子机制。方法肝积汤的活性成分及作用靶点从TCMSP数据库筛选,肝癌相关靶点从GeneCard数据库获取,运用String数据库对共同靶点做蛋白互作网络分析,GO和KEGG富集分析采用Bioconductor生物信息软件包进行,“成分－靶点－通路”网络图采用Cytoscape制作。结果 从 TCMSP 中获得肝积汤有效活性成分 80种以及249 个药效分子靶点。与检索到的885 个肝癌相关靶点取交集,得到95个共同靶点。蛋白互作网络分析显示有TP53、VEGFA、AKT1等15个核心靶点。GO 功能分析表明,这些靶点主要富集在细胞对化学应激的反应,细胞对氧化应激的反应,对脂多糖反应等；涉及细胞周期蛋白依赖性蛋白激酶全酶复合物、丝氨酸/苏氨酸蛋白激酶复合物,蛋白络氨酸激酶等,主要涉及DNA结合转录因子结合、RNA聚合酶Ⅱ特异性DNA结合转录因子结合、泛素样蛋白连接酶结合。KEGG 富集分析结果显示,肝积汤作用靶点富集在相关肝癌发生与发展的通路上,如PI3K-Akt信号通路、乙型肝炎病毒信号通路、人巨细胞病毒感染信号通路。结论 槲皮素、木犀草素、山柰酚等可能为肝积汤治疗肝癌的关键成分,TP53、VEGFA、AKT1等为核心靶点,PI3K-Akt、乙型肝炎病毒、人巨细胞病毒感染等通路为主要作用的通路。     

Implantation de la spectrométrie de masse de type MALDI-TOF dans les laboratoires de microbiologie : quels changements pour les cliniciens ?

Mass spectrometry (MS) has emerged as a particularly powerful tool for analysis and characterization of proteins in research for twenty years. More recently, matrix assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS) has been introduced in clinical laboratories for routine identification. This method is reliable and safe for the identification of bacteria, yeasts, filamentous fungi, and dermatophytes isolated from clinical samples by intact cell mass spectrometry or directly from positive blood culture or urines. Other applications are currently in development, including bacterial typing, detection of antibiotic resistance, and identification of virulent strains.     

Identifying autoantigens as theranostic targets: antigen arrays and immunoproteomics approaches

The development of theranostics holds great potential for the advancement of personalized medical treatments for human diseases. The theranostic approach combines diagnostic testing with predicted treatment outcomes in order to specifically tailor medical treatments for individual patients. As such, theranostic tests have the potential to revolutionize the diagnosis, treatment and monitoring of human diseases. Currently, the search is underway to identify novel targets for use in the development of theranostic approaches. The aims of this review are: to briefly describe the current capabilities of antigen-autoantibody microarrays, including our native antigen 'reverse-capture' autoantibody microarray platform to identify theranostic targets; to detail other immunoproteomics approaches for the identification of theranostic targets, including serological analysis of antigens by recombinant complementary (c)DNA expression cloning, serological proteome analysis, and autoantibody-mediated identification of antigens; and to provide examples of their use in theranostic discoveries.     

Clean image synthesis and target numerical marching for optical imaging with backscattering light

Scanning backscattering imaging and independent component analysis (ICA) are used to probe targets hidden in the subsurface of a turbid medium. A new correction procedure is proposed and used to synthesize a "clean" image of a homogeneous host medium numerically from a set of raster-scanned "dirty" backscattering images of the medium with embedded targets. The independent intensity distributions on the surface of the medium corresponding to individual targets are then unmixed using ICA of the difference between the set of dirty images and the clean image. The target positions are localized by a novel analytical method, which marches the target to the surface of the turbid medium until a match with the retrieved independent component is accomplished. The unknown surface property of the turbid medium is automatically accounted for by this method. Employing clean image synthesis and target numerical marching, three-dimensional (3D) localization of objects embedded inside a turbid medium using independent component analysis in a backscattering geometry is demonstrated for the first time, using as an example, imaging a small piece of cancerous prostate tissue embedded in a host consisting of normal prostate tissue.     

Simultaneous quantification of GM1 and GM2 gangliosides by isotope dilution tandem mass spectrometry

OBJECTIVES: Gangliosides (GGs) are considered as diagnostic biomarkers and therapeutic targets and agents. The goal of this study was to develop a tandem mass spectrometry (MS/MS) method for the simultaneous measurement of both GM1 and GM2 gangliosides in human cerebrospinal fluid (CSF) samples in order to be able to determine their concentrations in patients with Tay-Sachs and Sandhoff disease and assess whether drugs or transplantation affect their concentrations. DESIGN AND METHODS: An API-4000 tandem mass spectrometer equipped with TurboIonSpray source and Shimadzu HPLC system was employed to perform the analysis using isotope dilution with deuterium labeled internal standards. To a 1.5 mL conical plastic Eppendorf centrifuge tube, 40 microL of human CSF sample was added and mixed with 400 microL of internal standard solution for deproteinization. After centrifugation, 100 microL of supernatant was injected onto a C-18 column. After a 2.5 min wash, the switching valve was activated and the analytes were eluted from the column with a water/methanol gradient into the MS/MS system. Quantification by multiple reaction-monitoring (MRM) analysis was performed in the negative mode. RESULTS: The within-day coefficients of variation were <3% for GM1 and <2% for GM2 and the between-day coefficients of variation were <5% for both GM1 and GM2 at all concentrations tested. Accuracy ranged between 98% and 102% for both analytes. Good linearity was also obtained within the concentration range of 10-200 ng/mL (6.5-129.3 nmol/L) for GM1 and 5-100 ng/mL (3.6-72.3 nmol/L) for GM2 (r> or =0.995). CONCLUSIONS: A new simple, accurate, and fast isotope dilution tandem mass spectrometry method was developed for the simultaneous quantification of GM1 and GM2 gangliosides in a small amount of human CSF. Concentrations were measured in "normal" CSF and in CSF from patients with Tay-Sachs disease.