12-Plex UHPLC-MS/MS analysis of sarcosine in human urine using integrated principle of multiplex tags chemical isotope labeling and selective imprint enriching.

Urinary sarcosine was considered to be a potential biomarker for prostate cancer (Pca). In this work, an integrated strategy of multiplex tags chemical isotope labeling (MTCIL) combined with magnetic dispersive solid phase extraction (MDSPE), was proposed for specific extraction and high-throughput determination of sarcosine by ultra high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). In the past three months, we have developed 8-plex MTCIL reagents with excellent qualitative and quantitative performance. In this work, the multiplexing capacity of MTCIL reagents (MTCIL360/361/362/363/364/365/366/375/376/378/379/381) was increased 1.5-fold from 8-plex to 12-plex. MTCIL359 was prepared and used to label sarcosine standard as internal standard (IS). The structural analogue derivative (MTCIL373-sarcosine) of all targeted MTCIL-sarcosine derivatives was synthesized and used as a novel dummy template to prepare dummy magnetic molecularly imprinted polymers (DMMIPs). The integration of MTCIL and DMMIPs procedures were extremely favorable to excellent chromatographic separation and efficient mass spectrometric detection. The labeling efficiency, chromatographic retention and mass spectrometry responses of MTCIL reagents were consistent for sarcosine. In a single UHPLC-MS/MS run (2.0 min), this method can simultaneously quantify sarcosine in 12-plex urine samples and achieve unbiased concentrations comparison between different urine samples. Analytical parameters including linearity (R2 0.989-0.997), detection limits (0.02 nM), precision (2.6-11.5%), accuracy (96.1-107.4%), matrix effect, labeling and extraction efficiency were carefully validated. The proposed method was successfully applied for urinary sarcosine determination of healthy male individuals and Pca patients. It was found that the sarcosine concentrations in these two groups were statistically extremely significantly different (P < 0.001). The developed method was a powerful analytical tool to substantially promote the analysis throughput and large-scale experiments about the potential biomarker research.

13-Plex UHPLC-MS/MS Analysis of Hexanal and Heptanal Using Multiplex Tags Chemical Isotope Labeling Technology.

In this work, a new series of chemical isotope labeling reagents, levofloxacin-hydrazide-based mass tags (LHMTs) named as LHMT359/360/361/362/363/364/365/366/373/375/376/378/379/381 were first designed and synthesized for the high-throughput analysis of potential biomarkers containing hexanal and heptanal of lung cancer. We exploited a new core structure of levofloxacin-d3, which significantly enhanced the multiplexing capability. Among them, LHMT359 was used for labeling standard compounds as internal standards for quantification. Using LHMT373-heptanal as dummy template, dummy magnetic molecularly imprinted polymers (DMMIPs) were prepared for magnetic dispersive solid-phase extraction after derivatization procedure. Other 12 LHMTs were established for high-throughput labeling hexanal and heptanal in human serum samples. The presynthesized DMMIPs can selectively extract LHMTs-derivatives of hexanal and heptanal from equally mixed derivatization solutions. The enriched derivatives of hexanal and heptanal were quantified by ultrahigh-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). A single UHPLC-MS/MS run enabled simultaneously quantifying hexanal and heptanal from 12 serum samples only within 2 min. The limits of detection were all 0.5 pM for hexanal and heptanal. The accuracies from human serum samples ranged from -10.2% to +11.0% with the intra- and interday precisions less than 11.3%. Meanwhile, this method was successfully applied for the analysis of hexanal and heptanal in serum samples from healthy people and lung cancer patients. The results show that this method has the significant advantages of high sensitivity, accuracy, selectivity, and analysis-throughput. The method application indicates that the developed method is promising in the screening of suspected lung cancer patients.

Multiplexed derivatization strategy-based dummy molecularly imprinted polymers as sorbents for magnetic dispersive solid phase extraction of globotriaosylsphingosine prior to UHPLC-MS/MS quantitation.

A new series of 9-plex chemical isotope-labeling reagents, levofloxacin-based mass tags (LMTs) named as LMT359, 360, 361, 362, 363, 373, 375, 376, and 378, was firstly designed and synthesized for the high-throughput labeling of globotriaosylsphingosine (lyso-Gb3), a disease biomarker of Fabry disease. Creatively based on derivatization strategy-dummy template technique, dummy magnetic molecularly imprinted polymers (DMMIPs) were designed and prepared using LMT387-labeled lyso-Gb3 as a dummy template. The novel DMMIP material was used as sorbents for magnetic dispersive solid-phase extraction of 9-plexed LMT derivatives of lyso-Gb3 from equally mixed derivatization solutions. The enriched 8-plexed lyso-Gb3 derivatives from 8 real samples were quantified by ultra-high-performance liquid chromatography tandem mass spectrometry in a single run using simultaneously extracted LMT359-labeled standard lyso-Gb3 as internal standards. DMMIPs were characterized by using the transmission electron microscope (TEM), Fourier transform infrared, X-ray photoelectron spectroscopy, and some other characterization techniques. TEM micrograph showed that the prepared DMMIPs had an apparent imprinting layer. Triple-recognition abilities of DMMIPs towards LMT-lyso-Gb3 mainly rely on the hydrogen bonding, electrostatic attraction, hydrophobic interaction, and boronate affinity. The imprinting factor of DMMIPs towards LMT-lyso-Gb3 was 5.1. This method shows the advantages of high selectivity (triple recognition), high sensitivity, high accuracy (recovery 93.5-108.8%), and high throughput (8 samples in a single run). The proposed method was successfully applied to the determination of lyso-Gb3 in plasma samples with spiked recoveries in the range of 95.0-102.4%. This indicates that the method is promising in bioanalysis and medical testing of lyso-Gb3 in the future. Graphical abstract Synthesis of multiplexed derivatization reagents and its correlative molecularly imprinted polymers for magnetic extraction of globotriaosylsphingosine.

8-Plex stable isotope labeling absolute quantitation strategy combined with dual-targeted recognizing function material for simultaneous separation and determination of glucosylsphingosine and galactosylsphingosine in human plasma.

Glucosylsphingosine (GlcS) in plasma is considered to be a reliable biomarker of Gaucher disease. The detection difficulty of GlcS is that it is difficult to achieve simultaneous separation and quantification with its isomer galactosylsphingosine (GalS), a biomarker of Krabbe disease. In this work, a multiplexed stable isotope labeling absolute quantization strategy coupled with magnetic dispersive solid phase extraction using new prepared dummy magnetic molecularly imprinted polymers (DMMIPs) has been developed for this purpose by ultra high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). 8-Plex Amine-reactive Mass Difference Tags (M360/361/362/363/373/375/376/378-AMDTs), were designed, synthesized and used to label GalS and GlcS in different 8 plasma samples, respectively. Synchronously, M359-AMDTs was prepared and used to label mixed standards of GalS and GlcS, which served as internal standards in UHPLC-MS/MS quantitation. Then DMMIPs possessing dual recognition function were applied for specific enrichment and purification of all GlcS and GalS derivatives from a combined solution of labeled 8-plex plasma samples and mixed standards before UHPLC-MS/MS injection. The labeling efficiency, chromatographic retention and mass spectrometry responses of all the 9 AMDTs reagents were consistent for GlcS and GalS. The established and validated method enabled 8-plex plasma samples quantification in a single UHPLC-MS/MS run (<2.0 min). Good linearity of AMDTs-GlcS/GalS derivatives was obtained in the range of 0.02-800 nM. LODs of GlcS and GalS were both 0.005 nM. The recoveries were in the range of 96.1-107.2%. The method was successfully applied for multiplex quantitative analysis of GlcS and GalS in human plasma samples. The results indicated that this method was capable of better realizing the simultaneous separation and quantification of GalS and GlcS compared to reported methods.

Immunogenicity of adenovirus and DNA vaccines co-expressing P39 and lumazine synthase proteins of Brucella abortus in BALB/c mice.

Brucella poses a great threat to animal and human health. Vaccination is the most promising strategy in the effort to control Brucella abortus (B. abortus) infection, but the currently used live vaccines interfere with diagnostic tests and could potentially result in disease outbreak. Therefore, new subunit vaccines and combined immunization strategies are currently under investigation. In this study, immunogenicity and protection ability of a recombinant adenovirus and plasmid DNA vaccine co-expressing P39 and lumazine synthase proteins of B. abortus were evaluated based on the construction of the two molecular vaccines. Four immunization strategies (single adenovirus, single DNA, adenovirus/DNA, DNA/adenovirus) were investigated. The results showed that the immunization strategy of DNA priming followed by adenovirus boosting induced robust humoral and cellular immune responses, and it significantly reduced the numbers of B. abortus in a mouse model. These results suggest that it could be a potential antigen candidate for development of a new subunit vaccine against B. abortus infection.

ChREBP and LXRα mediate synergistically lipogenesis induced by glucose in porcine adipocytes.

Glucose is a substrate for fatty acid synthesis, and induces lipogenesis and expressions of lipogenic genes. It was proposed that transcriptional factor ChREBP, LXRα and SREBP-1c are key mediators in lipogenesis induced by glucose, however the underlying mechanism remains unclear in porcine adipocytes. In this study, glucose stimulated lipogenesis and expressions of ChREBP, LXRα, SREBP-1c and lipogenic genes FAS and ACC1 in primary porcine adipocytes. When ChREBP expression was knocked down by RNAi, lipogenesis and FAS and ACC1 expressions decreased significantly, and lipogenesis induced by glucose decreased by 75.6%, whereas neither the basal expressions under glucose-free nor glucose induced expressions of LXRα and SREBP-1c were evidently affected, suggesting that ChREBP was a main mediator of lipogenesis stimulated by glucose. Glucose promoted LXRα gene expression, and activation of LXRα by T0901317 increased SREBP-1c expression and enhanced the stimulation of glucose on lipogenesis, but this stimulatory effect of LXRα depended on glucose. Activated LXRα stimulated lipogenesis and ChREBP mRNA expression, which was much lower than that elevated by glucose, and was markedly lower in ChREBP-silencing than in unperturbed adipocytes. SREBP-1c activation blocked by fatostatin markedly decreased lipogenesis and expressions of FAS and ACC1 induced by glucose. Lipogenesis and lipogenic gene expression stimulated by LXRα activation were attenuated by fatostatin, however there was still a slightly increase in ChREBP-silencing adipocytes. These dates suggested that LXRα could directly or through SREBP-1c mediate the lipogenesis induced by glucose. Together, glucose induced lipogenesis and lipogenic gene expressions directly through ChREBP, and directly through LXRα or via SREBP-1c.