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2.
Nat Immunol ; 21(8): 868-879, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32690950

RESUMEN

STING is essential for control of infections and for tumor immunosurveillance, but it can also drive pathological inflammation. STING resides on the endoplasmic reticulum (ER) and traffics following stimulation to the ERGIC/Golgi, where signaling occurs. Although STING ER exit is the rate-limiting step in STING signaling, the mechanism that drives this process is not understood. Here we identify STEEP as a positive regulator of STING signaling. STEEP was associated with STING and promoted trafficking from the ER. This was mediated through stimulation of phosphatidylinositol-3-phosphate (PtdIns(3)P) production and ER membrane curvature formation, thus inducing COPII-mediated ER-to-Golgi trafficking of STING. Depletion of STEEP impaired STING-driven gene expression in response to virus infection in brain tissue and in cells from patients with STING-associated diseases. Interestingly, STING gain-of-function mutants from patients interacted strongly with STEEP, leading to increased ER PtdIns(3)P levels and membrane curvature. Thus, STEEP enables STING signaling by promoting ER exit.


Asunto(s)
Retículo Endoplásmico/metabolismo , Regulación de la Expresión Génica/fisiología , Proteínas de la Membrana/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Transducción de Señal/fisiología , Animales , Retículo Endoplásmico/inmunología , Humanos , Lupus Eritematoso Sistémico/inmunología , Lupus Eritematoso Sistémico/metabolismo , Proteínas de la Membrana/inmunología , Ratones , Proteínas del Tejido Nervioso/inmunología , Proteínas Nucleares , Transporte de Proteínas/fisiología
3.
Nanotechnology ; 35(13)2024 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-38134437

RESUMEN

Due to the unique ability to mimic natural enzymes, single-atom nanoenzymes (SAE) have garnered significant attention and research in tumor therapy. However, their efficacy often faces challenges in terms of drug delivery methods, and the research regarding their applications in radiotherapy is scarce. Herein, we introduce a light-controlled SAE hydrogel platform (SH) for glutathione-depletion-mediated low-dose radiotherapy. The SH incorporates a Cu single-atom enzyme (CuSA), and upon irradiation with 1064 nm near-infrared light, the CuSA can convert light energy into heat, which in turn degrades the hydrogel, enabling the release of CuSA into tumor cells or tissues. The diffused CuSA not only can facilitate the conversion of H2O2into hydroxyl radicals (•OH), but also can effectively depletes cellular glutathione. This leads to increased sensitivity of tumor cells to radiotherapy, resulting in enhanced cytotoxicity even at low doses. The animal study results further confirmed the good tumor-killing efficacy of this SH system. To the best of our knowledge, this stands as the pioneering report on leveraging a single-atom enzyme for GSH depletion-mediated low-dose radiotherapy.


Asunto(s)
Sistemas de Liberación de Medicamentos , Neoplasias , Animales , Difusión , Glutatión , Calor , Hidrogeles , Peróxido de Hidrógeno
4.
Sensors (Basel) ; 24(6)2024 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-38544246

RESUMEN

High-frequency workpieces have the characteristics of complex intra-class textures and small differences between classes, leading to the problem of low recognition rates when existing models are applied to the recognition of high-frequency workpiece images. We propose in this paper a novel high-frequency workpiece image recognition model that uses EfficientNet-B1 as the basic network and integrates multi-level network structures, designated as ML-EfficientNet-B1. Specifically, a lightweight mixed attention module is first introduced to extract global workpiece image features with strong illumination robustness, and the global recognition results are obtained through the backbone network. Then, the weakly supervised area detection module is used to locate the locally important areas of the workpiece and is introduced into the branch network to obtain local recognition results. Finally, the global and local recognition results are combined in the branch fusion module to achieve the final recognition of high-frequency workpiece images. Experimental results show that compared with various image recognition models, the proposed ML-EfficientNet-B1 model has stronger adaptability to illumination changes, significantly improves the performance of high-frequency workpiece recognition, and the recognition accuracy reaches 98.3%.

5.
Anal Chem ; 95(48): 17622-17628, 2023 12 05.
Artículo en Inglés | MEDLINE | ID: mdl-37997359

RESUMEN

Short-chain fatty acids (SCFAs), as the main metabolites of gut microbiota, are recognized as crucial players in the host's inflammatory response and metabolic disease. Imaging the spatial distributions and calculating the accurate contents of SCFAs in the heterogeneous intestinal tissue are critical to reveal their biological functions. Here, we develop an isotope-coded on-tissue derivatization method combined with matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) to map the spatial expressions of SCFAs in the colon tissue based on pair-labeled N,N,N-trimethyl-2-(piperazin-1-yl)ethan-1-aminium iodide (TMPA) and D3-TMPA. A noticeable increase in the MALDI-MSI sensitivity of SCFAs was achieved after on-tissue derivatization, which enables the visualization of acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, hydroxy acetic acid, and hydroxy propionic acid in the colon tissue. Moreover, the introduction of D3-TMPA-tagged SCFAs as internal standards can significantly reduce quantitation deviation from the matrix effects, ensuring the quantitative MALDI-MSI of SCFAs. We further used this method to characterize the spatial alterations of SCFAs in the colon tissues of mice with enterocolitis. The development of this strategy provides a reliable approach to image the spatial expressions of SCFAs in tissues and paves an insight way to study the roles of SCFAs in the gut microbiota and disease.


Asunto(s)
Ácidos Grasos Volátiles , Propionatos , Ratones , Animales , Ácidos Grasos Volátiles/análisis , Ácido Acético , Isótopos , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Ácido Butírico
6.
Anal Chem ; 95(41): 15153-15161, 2023 10 17.
Artículo en Inglés | MEDLINE | ID: mdl-37800909

RESUMEN

The metabolic cross-talk between tumor and immune cells plays key roles in immune cell function and immune checkpoint blockade therapy. However, the characterization of tumor immunometabolism and its spatiotemporal alterations during immune response in a complex tumor microenvironment is challenging. Here, a 3D tumor-immune cell coculture spheroid model was developed to mimic tumor-immune interactions, combined with mass spectrometry imaging-based spatially resolved metabolomics to visualize tumor immunometabolic alterations during immune response. The inhibition of T cells was simulated by coculturing breast tumor spheroids with Jurkat T cells, and the reactivation of T cells can be monitored through diminishing cancer PD-L1 expressions by berberine. This system enables simultaneously screening and imaging discriminatory metabolites that are altered during T cell-mediated antitumor immune response and characterizing the distributions of berberine and its metabolites in tumor spheroids. We discovered that the transport and catabolism of glutamine were significantly reprogrammed during the antitumor immune response at both metabolite and enzyme levels, corresponding to its indispensable roles in energy metabolism and building new biomass. The combination of spatially resolved metabolomics with the 3D tumor-immune cell coculture spheroid visually reveals metabolic interactions between tumor and immune cells and possibly helps decipher the role of immunometabolic alterations in tumor immunotherapy.


Asunto(s)
Berberina , Neoplasias , Humanos , Técnicas de Cocultivo , Neoplasias/patología , Esferoides Celulares/patología , Inmunidad , Microambiente Tumoral
7.
Cancer Cell Int ; 23(1): 177, 2023 Aug 24.
Artículo en Inglés | MEDLINE | ID: mdl-37620880

RESUMEN

BACKGROUND: Metabolic reprogramming refers to tumor-associated metabolic alterations during tumorigenesis and has been regarded as one of the most important features of cancer. Profiling the altered metabolites and lipids in hepatocellular carcinoma with spatial signature will not only enhance our understanding of tumor metabolic reprogramming, but also offer potential metabolic liabilities that might be exploited for hepatocellular carcinoma therapy. METHODS: We perform matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) analysis on both hepatocellular carcinoma xenograft mouse model and hepatocellular carcinoma patients. Discriminatory metabolites that altered during the development of hepatocellular carcinoma are screened and imaged in xenograft mouse model and are further validated in 21 hepatocellular carcinoma patients. RESULTS: We discover stepwise metabolic alterations and progressively increasing metabolic heterogeneity during the growth of hepatocellular carcinoma. Arginine and its metabolites spermine and spermidine, choline and phosphatidylcholine metabolism, and fatty acids were found to be significantly reprogrammed in hepatocellular carcinoma tissues. CONCLUSIONS: The spatially resolved profiling of the metabolites and lipids in highly heterogeneous hepatocellular carcinoma tissue will contribute to obtaining precise metabolic information for the understanding of tumor metabolic reprogramming.

8.
Cancer Cell Int ; 23(1): 83, 2023 Apr 29.
Artículo en Inglés | MEDLINE | ID: mdl-37120513

RESUMEN

BACKGROUND: Reprogrammed metabolic network is a key hallmark of cancer. Profiling cancer metabolic alterations with spatial signatures not only provides clues for understanding cancer biochemical heterogeneity, but also helps to decipher the possible roles of metabolic reprogramming in cancer development. METHODS: Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) technique was used to characterize the expressions of fatty acids in breast cancer tissues. Specific immunofluorescence staining was further carried out to investigate the expressions of fatty acid synthesis-related enzymes. RESULTS: The distributions of 23 fatty acids in breast cancer tissues have been mapped, and the levels of most fatty acids in cancer tissues are significantly higher than those in adjacent normal tissues. Two metabolic enzymes, fatty acid synthase (FASN) and acetyl CoA carboxylase (ACC), which being involved in the de novo synthesis of fatty acid were found to be up-regulated in breast cancer. Targeting the up-regulation of FASN and ACC is an effective approach to limiting the growth, proliferation, and metastasis of breast cancer cells. CONCLUSIONS: These spatially resolved findings enhance our understanding of cancer metabolic reprogramming and give an insight into the exploration of metabolic vulnerabilities for better cancer treatment.

9.
Mikrochim Acta ; 190(5): 192, 2023 04 26.
Artículo en Inglés | MEDLINE | ID: mdl-37099090

RESUMEN

AgBiS2 was hydrothermally synthesized, In2O3 was synthesized by hydrothermal method and calcination, and the type-II In2O3/AgBiS2 heterojunction material of an optimized composition ratio was cast-coated on a fluorine-doped tin oxide (FTO) slice to fabricate an In2O3/AgBiS2/FTO photoanode. The signal-attenuated photoelectrochemistry sandwich immunoassay of squamous cell carcinoma antigen (SCCA) was realized on this photoanode, on the basis of a bovine serum albumin/secondary antibody/CuO nanoparticles/nitrogen-doped porous carbon-ZnO bionanocomposite that can competitively absorb light and deplete the electron donor ascorbic acid as well as show the steric hindrance and p-n quenching effects. Under the optimized conditions (e.g., at a bias of 0 V vs. SCE), the photocurrent was linear with the common logarithm of SCCA concentration from 2.00 pg mL-1 to 50.0 ng mL-1, with a limit of detection (LOD) of 0.62 pg mL-1 (S/N = 3). The immunoassay of SCCA in human serum samples gave satisfactory recovery (92.0~103%) and relative standard deviation (5.1~7.8%) results.


Asunto(s)
Óxido de Zinc , Humanos , Óxido de Zinc/química , Carbono , Nitrógeno , Porosidad , Inmunoensayo/métodos
10.
Mikrochim Acta ; 190(5): 193, 2023 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-37103619

RESUMEN

A new BiVO4-carboxylated graphene (cG)-WO3 Z-scheme heterojunction was constructed on a fluorine-doped tin oxide (FTO) substrate electrode by ultrasonic mixing and cast-coating for determination of oxytetracycline (OTC). Since cG can absorb visible light and well match with the energy levels of WO3 and BiVO4 to promote the charge separation and transfer, the photocurrent on the BiVO4-cG-WO3/FTO photoelectrode is 4.4 times that on the control BiVO4-WO3/FTO photoelectrode. An amino-functionalized OTC aptamer was fixed on the BiVO4-cG-WO3/FTO photoelectrode by the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide mediated amide reaction, and then hexaammonium ruthenium(III) (Ru(NH3)63+) was attached to the OTC aptamer to increase the photocurrent response to the OTC binding. Under the optimized conditions, the photocurrent on the BiVO4-cG-WO3/FTO photoelectrode at 0 V vs SCE was linear with the common logarithm of OTC concentration from 0.01 nM to 500 nM, with a limit of detection of 3.1 pM (S/N = 3). Satisfactory recovery results were obtained in the analysis of real water samples.

11.
EMBO J ; 37(8)2018 04 13.
Artículo en Inglés | MEDLINE | ID: mdl-29496741

RESUMEN

Negative regulation of immune pathways is essential to achieve resolution of immune responses and to avoid excess inflammation. DNA stimulates type I IFN expression through the DNA sensor cGAS, the second messenger cGAMP, and the adaptor molecule STING Here, we report that STING degradation following activation of the pathway occurs through autophagy and is mediated by p62/SQSTM1, which is phosphorylated by TBK1 to direct ubiquitinated STING to autophagosomes. Degradation of STING was impaired in p62-deficient cells, which responded with elevated IFN production to foreign DNA and DNA pathogens. In the absence of p62, STING failed to traffic to autophagy-associated vesicles. Thus, DNA sensing induces the cGAS-STING pathway to activate TBK1, which phosphorylates IRF3 to induce IFN expression, but also phosphorylates p62 to stimulate STING degradation and attenuation of the response.


Asunto(s)
Nucleotidiltransferasas/fisiología , Proteínas Serina-Treonina Quinasas/fisiología , Proteína Sequestosoma-1/fisiología , Animales , Autofagia , Línea Celular , ADN/metabolismo , Humanos , Ratones Endogámicos C57BL , Ratones Noqueados , Transducción de Señal
12.
Analyst ; 147(12): 2678-2686, 2022 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-35611759

RESUMEN

Using an In2O3/WO3 type-II heterojunction modified fluorine-doped tin oxide (FTO) electrode as the photoanode and CdS quantum dots (QDs)-polydopamine nanospheres (PDA NSs) as the secondary antibody (Ab2) label, the photoelectrochemistry (PEC) sandwich immunosensing of the lung cancer marker CYFRA21-1 was studied. WO3 nanoplates were prepared by a hydrothermal method, In2O3 nanoporous spheres were prepared by a hydrothermal method followed by calcination, and the In2O3/WO3 type-II heterojunction with high PEC activity was prepared by ultrasonic mixing and cast-coating. PDA NSs with a high surface area can be loaded with abundant Ab2 molecules and many CdS QDs with an energy level well matched with the heterojunction, so the photocurrent signal can be amplified by the formation of a sandwich immunostructure. Through the simulation experiments of photoelectrode-modified chitosan films of varying thickness, the effective transport distance of photogenerated charges is preliminarily discussed. Under the optimized conditions, the photocurrent was linear with the common logarithm of CYFRA21-1 concentration from 100 fg mL-1 to 50 ng mL-1, with a limit of detection of 56 fg mL-1 (S/N = 3). The immunoassay of CYFRA21-1 in human serum samples gave satisfactory recovery results.


Asunto(s)
Técnicas Biosensibles , Compuestos de Cadmio , Indio , Nanosferas , Puntos Cuánticos , Humanos , Antígenos de Neoplasias , Técnicas Biosensibles/métodos , Compuestos de Cadmio/química , Técnicas Electroquímicas/métodos , Inmunoensayo/métodos , Indoles , Queratina-19 , Límite de Detección , Nanosferas/química , Polímeros , Puntos Cuánticos/química , Sulfuros/química
13.
Proc Natl Acad Sci U S A ; 116(1): 52-57, 2019 01 02.
Artículo en Inglés | MEDLINE | ID: mdl-30559182

RESUMEN

Characterization of tumor metabolism with spatial information contributes to our understanding of complex cancer metabolic reprogramming, facilitating the discovery of potential metabolic vulnerabilities that might be targeted for tumor therapy. However, given the metabolic variability and flexibility of tumors, it is still challenging to characterize global metabolic alterations in heterogeneous cancer. Here, we propose a spatially resolved metabolomics approach to discover tumor-associated metabolites and metabolic enzymes directly in their native state. A variety of metabolites localized in different metabolic pathways were mapped by airflow-assisted desorption electrospray ionization mass spectrometry imaging (AFADESI-MSI) in tissues from 256 esophageal cancer patients. In combination with in situ metabolomics analysis, this method provided clues into tumor-associated metabolic pathways, including proline biosynthesis, glutamine metabolism, uridine metabolism, histidine metabolism, fatty acid biosynthesis, and polyamine biosynthesis. Six abnormally expressed metabolic enzymes that are closely associated with the altered metabolic pathways were further discovered in esophageal squamous cell carcinoma (ESCC). Notably, pyrroline-5-carboxylate reductase 2 (PYCR2) and uridine phosphorylase 1 (UPase1) were found to be altered in ESCC. The spatially resolved metabolomics reveal what occurs in cancer at the molecular level, from metabolites to enzymes, and thus provide insights into the understanding of cancer metabolic reprogramming.


Asunto(s)
Metabolómica/métodos , Neoplasias/metabolismo , Carcinoma de Células Escamosas/enzimología , Carcinoma de Células Escamosas/metabolismo , Neoplasias Esofágicas/enzimología , Neoplasias Esofágicas/metabolismo , Ensayos Analíticos de Alto Rendimiento , Humanos , Espectrometría de Masas , Neoplasias/enzimología , Neoplasias/patología , Pirrolina Carboxilato Reductasas/metabolismo , Uridina Fosforilasa/metabolismo
14.
Mikrochim Acta ; 189(7): 265, 2022 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-35776227

RESUMEN

The photoelectrochemical immunoassay of glycogen phosphorylase BB (GPBB) was studied. A methyl orange/TiO2 nanorod heterojunction was constructed on a fluorine-doped tin oxide electrode by hydrothermal synthesis, calcination, and chemical adsorption. A sandwich immune structure consisting of GPBB as the first antibody, GPBB, and a CdS@mesoporous silica-ascorbic acid (AA)-GPBB as secondary antibody composite was constructed on each of the selected well surfaces of a 96-well microplate. By adding mercaptoethylamine to structurally destroy the secondary antibody composite and release the electron donor AA, the amplification of photocurrent, and thus the "off-on" photoelectrochemical biosensing of GPBB were realized. The use of the 96-well microplate provides good reproducibility of the assembled immune structures and eliminates the possible effect of the photogenerated hole-induced protein oxidation on the photocurrent. The relevant electrodes and materials were characterized by electrochemistry, UV-vis diffuse reflectance spectra, Fourier transform infrared spectroscopy, X-ray diffractometer, scanning electron microscopy/energy dispersive spectroscopy, transmission electron microscopy and BET method. Under the optimal conditions, the photocurrent was linear with the logarithm of GPBB concentration from 0.005 to 200 ng mL-1 and with a limit of detection of 1.7 pg mL-1 (S/N = 3). Satisfactory results were obtained in the analysis of real serum samples. A sandwich immune structure consisting of GPBB first antibody, GPBB, and a CdS@mesoporous silica-ascorbic acid (AA)-GPBB secondary antibody composite was constructed on each of the selected well surfaces of a 96-well microplate. By adding mercaptoethylamine to structurally destroy the secondary antibody composite and release the electron donor AA, the amplification of photocurrent, and thus the "off-on" photoelectrochemical biosensing of GPBB were realized.


Asunto(s)
Mercaptoetilaminas , Nanotubos , Ácido Ascórbico , Compuestos Azo , Encéfalo , Glucógeno Fosforilasa , Inmunoensayo/métodos , Nanotubos/química , Reproducibilidad de los Resultados , Dióxido de Silicio , Titanio
15.
Molecules ; 27(4)2022 Feb 18.
Artículo en Inglés | MEDLINE | ID: mdl-35209182

RESUMEN

The pathological diagnosis of benign and malignant follicular thyroid tumors remains a major challenge using the current histopathological technique. To improve diagnosis accuracy, spatially resolved metabolomics analysis based on air flow-assisted desorption electrospray ionization mass spectrometry imaging (AFADESI-MSI) technique was used to establish a molecular diagnostic strategy for discriminating four pathological types of thyroid tumor. Without any specific labels, numerous metabolite features with their spatial distribution information can be acquired by AFADESI-MSI. The underlying metabolic heterogeneity can be visualized in line with the cellular heterogeneity in native tumor tissue. Through micro-regional feature extraction and in situ metabolomics analysis, three sets of metabolic biomarkers for the visual discrimination of benign follicular adenoma and differentiated thyroid carcinomas were discovered. Additionally, the automated prediction of tumor foci was supported by a diagnostic model based on the metabolic profile of 65 thyroid nodules. The model prediction accuracy was 83.3% when a test set of 12 independent samples was used. This diagnostic strategy presents a new way of performing in situ pathological examinations using small molecular biomarkers and provides a model diagnosis for clinically indeterminate thyroid tumor cases.


Asunto(s)
Biomarcadores de Tumor , Metabolómica , Técnicas de Diagnóstico Molecular , Neoplasias de la Tiroides/diagnóstico , Neoplasias de la Tiroides/metabolismo , Técnica del Anticuerpo Fluorescente , Humanos , Inmunohistoquímica , Metaboloma , Metabolómica/métodos , Pronóstico , Curva ROC , Espectrometría de Masa por Ionización de Electrospray , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Neoplasias de la Tiroides/etiología
16.
Entropy (Basel) ; 24(7)2022 Jun 22.
Artículo en Inglés | MEDLINE | ID: mdl-35885079

RESUMEN

This paper studies the agent identity privacy problem in the scalar linear quadratic Gaussian (LQG) control system. The agent identity is a binary hypothesis: Agent A or Agent B. An eavesdropper is assumed to make a hypothesis testing the agent identity based on the intercepted environment state sequence. The privacy risk is measured by the Kullback-Leibler divergence between the probability distributions of state sequences under two hypotheses. By taking into account both the accumulative control reward and privacy risk, an optimization problem of the policy of Agent B is formulated. This paper shows that the optimal deterministic privacy-preserving LQG policy of Agent B is a linear mapping. A sufficient condition is given to guarantee that the optimal deterministic privacy-preserving policy is time-invariant in the asymptotic regime. It is also shown that adding an independent Gaussian random process noise to the linear mapping of the optimal deterministic privacy-preserving policy cannot improve the performance of Agent B. The numerical experiments justify the theoretic results and illustrate the reward-privacy trade-off.

17.
Phytochem Anal ; 32(4): 457-465, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32945032

RESUMEN

INTRODUCTION: Flavonoids are the most important and effective constituents in the thorns of Gleditsia sinensis Lam., which have been known to show antimicrobial, antiviral, anticancer, and anticoagulant activities. However, efficient extraction and separation methods for these flavonoids are not currently established. OBJECTIVE: To develop an efficient method for efficient extraction and rapid separation of flavonoids from the thorns of G. sinensis using choline chloride deep eutectic solvents (DESs) and high-speed counter-current chromatography (HSCCC). METHODOLOGY: As for extraction, DES composed of choline chloride and 1,4-butanediol at 1:4 mole ratio, at an extraction temperature of 55°C, 20% of water content, 1:30 mg/mL for solid-liquid ratio, and 45 min for extraction time were selected as the optimised extraction method for flavonoids from the thorns of G. sinensis. As for separation, dichloromethane-methanol-n-butanol-water (4:3:0.5:2, v/v) was applied to develop a successful strategy for purification of the flavonoids by HSCCC. RESULTS: Totally, five flavonoids, including padmatin (1, 3.7 mg), isovitexin (2, 2.5 mg), 3',5,5',7-tetrahydroxyflavanonol (3, 11.2 mg), 7,4'-dihydroxy-5,3'-dimethoxyflavanonol (4, 4.1 mg), and quercetin (5, 3.8 mg), were successfully obtained from 250 mg of the extracted flavonoids by HSCCC. CONCLUSION: Results demonstrated that the combination of DES and HSCCC is a powerful technique for the extraction, and isolation of flavonoids from the thorns of G. sinensis compared with conventional organic solvent extraction and column chromatography, which have been proven to provide higher extraction efficiency for flavonoids and rapidly obtain the quality control markers of flavonoids from the investigated plant.


Asunto(s)
Flavonoides , Gleditsia , Colina , Cromatografía Líquida de Alta Presión , Distribución en Contracorriente , Flavonoides/análisis , Extractos Vegetales , Solventes
18.
Anal Chem ; 92(18): 12126-12131, 2020 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-32786442

RESUMEN

Carboxyl-containing metabolites (CCMs) play indispensable roles in cell energy metabolism and cell-cell signaling. Profiling tissue CCMs with spatial signatures is significant for the understanding of molecular histology and may provide new clues to uncover the complex metabolic reprogramming of organisms in response to external or internal stimuli. Here, we develop a sensitive on-tissue CCMs derivatization method, coupled with matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI), to visualize the spatial distributions of CCMs in biological tissues. A novel reagent, N,N,N-trimethyl-2-(piperazin-1-yl)ethan-1-aminium iodide (TMPA), was synthesized and used for the on-tissue derivatization of CCMs. Meanwhile, the on-tissue derivatization efficiency was significantly improved by introducing acetonitrile gas in the incubation system. With this methodology, a total of 28 CCMs, including 5 tricarboxylic acid cycle intermediates, 20 fatty acids, and 3 bile acids, were successfully detected and imaged in rat kidney tissues. More importantly, the introduction of a quaternary ammonium group into the chemical structure of CCMs enables simultaneous MALDI-MS imaging of tricarboxylic acid cycle intermediates, fatty acids, bile acids, and their metabolic pathway-related metabolites such as carnitines, cholines, glycerophosphocholine, phospholipids, and so on in the positive ion mode. This on-tissue derivatization MALDI-MSI approach was proven to be a powerful tool for probing the distributions and spatial metabolic networks of CMMs in biological tissues.


Asunto(s)
Encéfalo/metabolismo , Riñón/química , Piperazinas/química , Animales , Riñón/metabolismo , Estructura Molecular , Piperazinas/metabolismo , Ratas , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción
19.
Anal Bioanal Chem ; 412(13): 3123-3134, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32236659

RESUMEN

The application of mass spectrometry imaging (MSI) for the study of spatiotemporal alterations of the metabolites in tumors has brought a number of significant biological results. At present, metabolite profiling based on MSI is typically performed on frozen tissue sections; however, the majority of clinical specimens need to be fixed in tissue fixative to avoid autolysis and to preserve antigenicity. In this study, we present the global impacts of different fixatives on the MS imaging of gastric cancer tissue metabolites. The MSI performances of 17 kinds of metabolites, such as amino acids, polyamines, cholines, organic acids, polypeptides, nucleotides, nucleosides, nitrogen bases, cholesterols, fatty acids, and phospholipids, in untreated, 10% formalin-, 4% paraformaldehyde-, acetone-, and 95% ethanol-fixed gastric cancer tissues were thoroughly explored for the first time. Furthermore, we also investigated the spatial expressions of 6 metabolic enzymes, namely, GLS, FASN, CHKA, PLD2, cPLA2, and EGFR, closely related to tumor-associated metabolites. Immunohistochemical staining carried out on the same tissue sections' which have undergone MSI analysis' suggests that enzymatic characterization is feasible after metabolite imaging. Combining the spatial signatures of metabolites and pathway-related metabolic enzymes in heterogeneous tumor tissues offers an insight to understand the complex tumor metabolism. Graphical abstract.


Asunto(s)
Fijadores/química , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Neoplasias Gástricas/metabolismo , Formaldehído/química , Humanos
20.
Environ Microbiol ; 21(8): 2707-2723, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-30882983

RESUMEN

Toxin/antitoxin (TA) systems are ubiquitous in bacteria and archaea and participate in biofilm formation and stress responses. The higBA locus of the opportunistic pathogen Pseudomonas aeruginosa encodes a type II TA system. Previous work found that the higBA operon is cotranscribed and that HigB toxin regulates biofilm formation and virulence expression. In this study, we demonstrate that HigA antitoxin is produced at a higher level than HigB and that higA mRNA is expressed separately from a promoter inside higB during the late stationary phase. Critically, HigA represses the expression of mvfR, which is an important virulence-related regulator, by binding to a conserved HigA palindrome (5'-TTAAC GTTAA-3') in the mvfR promoter, and the binding of HigB to HigA derepresses this process. During the late stationary phase, excess HigA represses the expression of mvfR and higBA. However, in the presence of aminoglycoside antibiotics where Lon protease is activated, the degradation of HigA by Lon increases P. aeruginosa virulence by simultaneously derepressing mvfR and higB transcription. Therefore, this study reveals that the antitoxin of the P. aeruginosa TA system is integrated into the key virulence regulatory network of the host and functions as a transcriptional repressor to control the production of virulence factors.


Asunto(s)
Proteínas Bacterianas/genética , Pseudomonas aeruginosa/genética , Sistemas Toxina-Antitoxina , Proteínas Bacterianas/metabolismo , Expresión Génica , Regulación Bacteriana de la Expresión Génica , Operón , Regiones Promotoras Genéticas , Pseudomonas aeruginosa/metabolismo , Pseudomonas aeruginosa/patogenicidad , Sistemas Toxina-Antitoxina/genética , Virulencia/genética , Factores de Virulencia
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