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1.
Brief Bioinform ; 23(4)2022 07 18.
Article in English | MEDLINE | ID: mdl-35794722

ABSTRACT

Drug target discovery is an essential step to reveal the mechanism of action (MoA) underlying drug therapeutic effects and/or side effects. Most of the approaches are usually labor-intensive while unable to identify the tissue-specific interacting targets, especially the targets with weaker drug binding affinity. In this work, we proposed an integrated pipeline, FL-DTD, to predict the drug interacting targets of novel compounds in a tissue-specific manner. This method was built based on a hypothesis that cells under a status of homeostasis would take responses to drug perturbation by activating feedback loops. Therefore, the drug interacting targets can be predicted by analyzing the network responses after drug perturbation. We evaluated this method using the expression data of estrogen stimulation, gene manipulation and drug perturbation and validated its good performance to identify the annotated drug targets. Using STAT3 as a target protein, we applied this method to drug perturbation data of 500 natural compounds and predicted five compounds with STAT3 interacting activities. Experimental assay validated the STAT3-interacting activities of four compounds. Overall, our evaluation suggests that FL-DTD predicts the drug interacting targets with good accuracy and can be used for drug target discovery.


Subject(s)
Drug Delivery Systems , Drug Discovery , Drug Discovery/methods , Feedback
2.
BMC Med Imaging ; 24(1): 58, 2024 Mar 05.
Article in English | MEDLINE | ID: mdl-38443786

ABSTRACT

BACKGROUND: MULTIPLEX is a single-scan three-dimensional multi-parametric MRI technique that provides 1 mm isotropic T1-, T2*-, proton density- and susceptibility-weighted images and the corresponding quantitative maps. This study aimed to investigate its feasibility of clinical application in Parkinson's disease (PD). METHODS: 27 PD patients and 23 healthy control (HC) were recruited and underwent a MULTIPLEX scanning. All image reconstruction and processing were automatically performed with in-house C + + programs on the Automatic Differentiation using Expression Template platform. According to the HybraPD atlas consisting of 12 human brain subcortical nuclei, the region-of-interest (ROI) based analysis was conducted to extract quantitative parameters, then identify PD-related abnormalities from the T1, T2* and proton density maps and quantitative susceptibility mapping (QSM), by comparing patients and HCs. RESULTS: The ROI-based analysis revealed significantly decreased mean T1 values in substantia nigra pars compacta and habenular nuclei, mean T2* value in subthalamic nucleus and increased mean QSM value in subthalamic nucleus in PD patients, compared to HCs (all p values < 0.05 after FDR correction). The receiver operating characteristic analysis showed all these four quantitative parameters significantly contributed to PD diagnosis (all p values < 0.01 after FDR correction). Furthermore, the two quantitative parameters in subthalamic nucleus showed hemicerebral differences in regard to the clinically dominant side among PD patients. CONCLUSIONS: MULTIPLEX might be feasible for clinical application to assist in PD diagnosis and provide possible pathological information of PD patients' subcortical nucleus and dopaminergic midbrain regions.


Subject(s)
Multiparametric Magnetic Resonance Imaging , Parkinson Disease , Humans , Feasibility Studies , Parkinson Disease/diagnostic imaging , Protons , Dopamine
3.
Nano Lett ; 23(21): 10004-10012, 2023 Nov 08.
Article in English | MEDLINE | ID: mdl-37877790

ABSTRACT

Cation exchange (CE) in metal oxides under mild conditions remains an imperative yet challenging goal to tailor their composition and enable practical applications. Herein, we first develop an amorphization-induced strategy to achieve room-temperature CE for universally synthesizing single-atom doped In2O3 nanosheets (NSs). Density functional theory (DFT) calculations elucidate that the abundant coordination-unsaturated sites present in a-In2O3 NSs are instrumental in surmounting the energy barriers of CE reactions. Empirically, a-In2O3 NSs as the host materials successfully undergo exchange with unary cations (Cu2+, Co2+, Mn2+, Ni2+), binary cations (Co2+Mn2+, Co2+Ni2+, Mn2+Ni2+), and ternary cations (Co2+Mn2+Ni2+). Impressively, high-loading single-atom doped (over 10 atom %) In2O3 NSs were obtained. Additionally, Cu/a-In2O3 NSs exhibit an excellent ethanol yield (798.7 µmol g-1 h-1) with a high selectivity of 99.5% for the CO2 photoreduction. This work offers a new approach to induce CE reactions in metal oxides under mild conditions and constructs scalable single-atom doped catalysts for critical applications.

4.
Angew Chem Int Ed Engl ; 63(30): e202316755, 2024 Jul 22.
Article in English | MEDLINE | ID: mdl-38739420

ABSTRACT

The hydrazine oxidation-assisted H2 evolution method promises low-input and input-free hydrogen production. However, developing high-performance catalysts for hydrazine oxidation (HzOR) and hydrogen evolution (HER) is challenging. Here, we introduce a bifunctional electrocatalyst α-MoC/N-C/RuNSA, merging ruthenium (Ru) nanoclusters (NCs) and single atoms (SA) into cubic α-MoC nanoparticles-decorated N-doped carbon (α-MoC/N-C) nanowires, through electrodeposition. The composite showcases exceptional activity for both HzOR and HER, requiring -80 mV and -9 mV respectively to reach 10 mA cm-2. Theoretical and experimental insights confirm the importance of two Ru species for bifunctionality: NCs enhance the conductivity, and its coexistence with SA balances the H ad/desorption for HER and facilitates the initial dehydrogenation during the HzOR. In the overall hydrazine splitting (OHzS) system, α-MoC/N-C/RuNSA excels as both anode and cathode materials, achieving 10 mA cm-2 at just 64 mV. The zinc hydrazine (Zn-Hz) battery assembled with α-MoC/N-C/RuNSA cathode and Zn foil anode can exhibit 97.3 % energy efficiency, as well as temporary separation of hydrogen gas during the discharge process. Therefore, integrating Zn-Hz with OHzS system enables self-powered H2 evolution, even in hydrazine sewage. Overall, the amalgamation of NCs with SA achieves diverse catalytic activities for yielding multifold hydrogen gas through advanced cell-integrated-electrolyzer system.

5.
Anal Chem ; 95(27): 10221-10230, 2023 07 11.
Article in English | MEDLINE | ID: mdl-37358923

ABSTRACT

Spatial metabolomic analysis of individual tumor spheroids can help investigate metabolic rearrangements in different cellular regions of a spheroid. In this work, a nanocapillary-based electrospray ionization mass spectroscopy (ESI-MS) method is established that could realize the spatial sampling of cellular components in different regions of a single living tumor spheroid and the subsequent MS analysis for a metabolic study. During the penetration of the nanocapillary into the spheroid for sampling, this "wound surface" at the outer layer of the spheroid takes only 0.1% of the whole area that maximally maintains the cellular activity inside the spheroid for the metabolic analysis. Using the ESI-MS analysis, different metabolic activities in the inner and outer (upper and lower) layers of a single spheroid are revealed, giving a full investigation of the metabolic heterogeneity inside one living tumor spheroid for the first time. In addition, the metabolic activities between the outer layer of the spheroid and two-dimensional (2D)-cultured cells show obvious differences, which suggests more frequent cell-cell and cell-extracellular environment interactions during the culture of the spheroid. This observation not only establishes a powerful tool for the in situ spatial analysis of the metabolic heterogeneity in single living tumor spheroids but also provides molecular information to elucidate the metabolic heterogeneity in this three-dimensional (3D)-cultured cell model.


Subject(s)
Neoplasms , Spheroids, Cellular , Humans , Spheroids, Cellular/pathology , Spectrometry, Mass, Electrospray Ionization , Neoplasms/pathology
6.
Angew Chem Int Ed Engl ; 62(34): e202303053, 2023 08 21.
Article in English | MEDLINE | ID: mdl-37334855

ABSTRACT

The in-depth study of single cells requires the dynamically molecular information in one particular nanometer-sized organelle in a living cell, which is difficult to achieve using current methods. Due to high efficiency of click chemistry, a new nanoelectrode-based pipette architecture with dibenzocyclooctyne at the tip is designed to realize fast conjugation with azide group-containing triphenylphosphine, which targets mitochondrial membranes. The covalent binding of one mitochondrion at the tip of the nanopipette allows a small region of the membrane to be isolated on the Pt surface inside the nanopipette. Therefore, the release of reactive oxygen species (ROS) from the mitochondrion is monitored, which is not interfered by the species present in the cytosol. The dynamic tracking of ROS release from one mitochondrion reveals the distinctive "ROS-induced ROS release" within the mitochondria. Further study of RSL3-induced ferroptosis using nanopipettes provides direct evidence for supporting the noninvolvement of glutathione peroxidase 4 in the mitochondria during RSL3-induced ROS generation, which has not previously been observed at the single-mitochondrion level. Eventually, this established strategy should overcome the existing challenge of the dynamic measurement of one special organelle in the complicated intracellular environment, which opens a new direction for electroanalysis in subcellular analysis.


Subject(s)
Mitochondria , Cell Survival , Mitochondria/chemistry , Mitochondria/metabolism , Click Chemistry/instrumentation , Click Chemistry/methods , Reactive Oxygen Species/metabolism
7.
J Am Chem Soc ; 144(38): 17558-17566, 2022 09 28.
Article in English | MEDLINE | ID: mdl-36112975

ABSTRACT

Measuring the activity of low-abundance enzymes, down to a few molecules in one living cell, is important but challenging to elucidate their biological function. Here, an electrochemical molecule trap is established at the tip of a nanopipette with an electrochemical detector, in which the diffusion of the molecules away from the electrochemical detector is prevented by electro-osmotic flow (EOF). Accordingly, a limited amount of enzymes is trapped to continuously catalyze the conversion of the substrate to generate a sufficient amount of the byproduct hydrogen peroxide for electrochemical measurements. The resistive pulse sensing of the enzymes in single liposomes validates the detection sensitivity down to 15 molecules. Using this ultrasensitive electrochemical strategy, the activity of 60 sphingomyelinase molecules inside single unstimulated living J774 cells is measured, which was hardly detected by previous methods. The established electrochemical molecule trap-based sensing approach opens the door toward single-molecule electrochemical detection in one living cell. This success will solve the long-standing problem regarding the study of the activity of low-abundance proteins in cells in their native physiological state and greatly enhance the understanding of the roles of proteins in cellular behavior.


Subject(s)
Hydrogen Peroxide , Sphingomyelin Phosphodiesterase , Catalysis , Electrochemical Techniques/methods , Hydrogen Peroxide/chemistry , Liposomes , Nanotechnology/methods
8.
Anal Chem ; 94(38): 13287-13292, 2022 09 27.
Article in English | MEDLINE | ID: mdl-36108154

ABSTRACT

The analysis of biomolecules in a 3D cell model is crucial for the collection of spatial information close to the actual organ. In this work, a highly sensitive platinized open carbon nanocavity electrode is fabricated to investigate reactive oxygen species (ROS) in three regions (proliferating zone, quiescent zone, and necrotic core) of a 3D CT26 cell model. The presence of a nanocavity permits more frequent collisions of ROS on the Pt surface, accelerating electron transfer, and thus pushes the detection limit down to 1 nM. This improved detection sensitivity guarantees the spatial investigation of the ROS distribution in a 3D cell sphere, including a high concentration in the outer proliferating layer even without any external stimulus, a low concentration in the quiescent layer, and almost no ROS at the center. The observation of ROS in the cell sphere without the stimulus reveals the presence of oxygen stress in the 3D cancer cell model, which is obviously different from the previous observation in living cultured 2D cells. This discovery provides direct evidence about the discrepancy about the metabolism in 2D and 3D cells, which could also direct a new study in cell electroanalysis to achieve more actual molecular information in life study.


Subject(s)
Carbon , Oxygen , Electrodes , Oxygen/metabolism , Reactive Oxygen Species/metabolism , Spatial Analysis
9.
BMC Biol ; 19(1): 166, 2021 08 20.
Article in English | MEDLINE | ID: mdl-34416880

ABSTRACT

BACKGROUND: Left-right (LR) asymmetry is an essential feature of bilateral animals. Studies in vertebrates show that LR asymmetry formation comprises three major steps: symmetry breaking, asymmetric gene expression, and LR morphogenesis. Although much progress has been made in the first two events, mechanisms underlying asymmetric morphogenesis remain largely unknown due to the complex developmental processes deployed by vertebrate organs. RESULTS: We here addressed this question by studying Pitx gene function in the basal chordate amphioxus whose asymmetric organogenesis, unlike that in vertebrates, occurs essentially in situ and does not rely on cell migration. Pitx null mutation in amphioxus causes loss of all left-sided organs and incomplete ectopic formation of all right-sided organs on the left side, whereas Pitx partial loss-of-function leads to milder phenotypes with only some LR organs lost or ectopically formed. At the N1 to N3 stages, Pitx expression is gradually expanded from the dorsal anterior domain to surrounding regions. This leads to activation of genes like Lhx3 and/or Prop1 and Pit, which are essential for left-side organs, and downregulation of genes like Hex and/or Nkx2.1 and FoxE4, which are required for right-side organs to form ectopically on the left side. In Pitx mutants, the left-side expressed genes are not activated, while the right-side genes fail to decrease expression on the left side. In contrast, in embryos overexpressing Pitx genes, the left-side genes are induced ectopically on the right side, and the right-side genes are inhibited. Several Pitx binding sites are identified in the upstream sequences of the left-side and right-side genes which are essential for activation of the former and repression of the latter by Pitx. CONCLUSIONS: Our results demonstrate that (1) Pitx is a major (although not the only) determinant of asymmetric morphogenesis in amphioxus, (2) the development of different LR organs have distinct requirements for Pitx activity, and (3) Pitx controls amphioxus LR morphogenesis probably through inducing left-side organs and inhibiting right-side organs directly. These findings show much more dependence of LR organogenesis on Pitx in amphioxus than in vertebrates. They also provide insight into the molecular developmental mechanism of some vertebrate LR organs like the lungs and atria, since they show a right-isomerism phenotype in Pitx2 knockout mice like right-sided organs in Pitx mutant amphioxus. Our results also explain why some organs like the adenohypophysis are asymmetrically located in amphioxus but symmetrically positioned in vertebrates.


Subject(s)
Lancelets , Animals , Body Patterning/genetics , Gene Expression Regulation, Developmental , Lancelets/genetics , Mice , Morphogenesis/genetics , Signal Transduction , Vertebrates
10.
Nano Lett ; 21(14): 6228-6236, 2021 Jul 28.
Article in English | MEDLINE | ID: mdl-34279970

ABSTRACT

For realizing scalable solar hydrogen synthesis, the development of visible-light-absorbing photocatalysts capable of overall water splitting is essential. Metal sulfides can capture visible light efficiently; however, their utilization in water splitting has long been plagued by the poor resilience against hole oxidation. Herein, we report that the ZnIn2S4 monolayers with dual defects (Ag dopants and nanoholes) accessed via cation exchange display stoichiometric H2 and O2 evolution in pure water under visible light irradiation. In-depth characterization and modeling disclose that the dual-defect structure endows the ZnIn2S4 monolayers with optimized light absorption and carrier dynamics. More significantly, the dual defects cooperatively function as active sites for water oxidation (Ag dopants) and reduction (nanoholes), thus leading to steady performance in photocatalytic overall water splitting without the assistance of cocatalysts. This work demonstrates a feasible way for fulfilling "all-in-one" photocatalyst design and manifests its great potential in addressing the stability issues associated with sulfide-based photocatalysts.

11.
Molecules ; 28(1)2022 Dec 20.
Article in English | MEDLINE | ID: mdl-36615213

ABSTRACT

Huangqin is the dried root of Scutellaria baicalensis Georgi, which has been widely utilized for heat-clearing (Qingre) and dewetting (Zaoshi), heat-killed (Xiehuo) and detoxifying (Jiedu) in the concept of Traditional Chinese Medicine and is used for treating inflammation and cancer in clinical formulas. Neobaicalein (NEO) is of flavonoid isolated from Huangqin and has been reported to possess prominent anti-inflammatory effects in published work. Th17/Treg balance shift to Th17 cells is an essential reason for autoimmune inflammatory diseases. However, the role NEO plays in Th17 and Treg and the underlying mechanism has not been elucidated yet. Network pharmacology-based study revealed that NEO predominantly regulated IL-17 signaling pathway. Moreover, our result shown that NEO (3-30 µmol/L) down-regulated Th17 differentiation and cellular supernatant and intracellular IL-17A level and tumor necrosis factor α production in a concentration-dependent manner. The further mechanism research revealed that NEO also specifically inhibited phosphorylation of STAT3(Tyr725) and STAT4 (Y693) without influence on activation of STAT5 and STAT6 in splenocytes. Immunofluorescence results illuminated that NEO effectively blocked STAT3 translocated into nucleus. Interestingly, NEO at appreciated dose could only inhibit Th17 cell differentiation and have no effect on Treg differentiation. The present study revealed that NEO effectively inhibited Th17 cell differentiation through specifically blocking the activation of STAT3 signaling without inactivation of STAT5 and STAT6. Additional inhibitory effect on activation of STAT4 by NEO also suggested the potential for antagonism against Th1 differentiation. All work suggested that NEO may be a potential candidate for immunoregulation and treating autoimmune inflammatory diseases through inhibiting immune cell viability and T cell differentiation.


Subject(s)
Autoimmune Diseases , Th17 Cells , Humans , STAT5 Transcription Factor/metabolism , T-Lymphocytes, Regulatory , Cell Differentiation , Signal Transduction , STAT3 Transcription Factor/metabolism , Autoimmune Diseases/metabolism
12.
Anal Chem ; 93(43): 14521-14526, 2021 11 02.
Article in English | MEDLINE | ID: mdl-34666486

ABSTRACT

The chemical reaction in a confined space is known to be accelerated due to a high collision probability; however, the study of this confinement effect in a supersmall space down to femtoliter (fL) is seldom reported. Here, an adjustable volume [from picoliter (pL) to fL] of the aqueous phase is retrained at the tip of a nanopipette by an organic solvent so that the confinement effect on the specific activity of glucose oxidase is investigated. The activity is determined by the amount of hydrogen peroxide generated from the reaction between the oxidase and glucose using a nanoelectrode inside the nanopipette. As compared with the activity in bulk solution (82 U/mg), the activity increases up to 7500 U/mg in a 105 fL space. The 2 orders of magnitude increase in the enzymatic activity is the highest amplification in the volume-confined enzyme reaction as reported. A near-exponential drop in the activity is observed with the increase in the space volume, revealing the dominant enhancement in the confined space at the fL level for the first time. The established electrochemical nanopipettes should not only provide a strategy for the study of the enzymatic activity in supersmall confined space but also help understand the confinement effect of enzyme-catalyzed reactions.


Subject(s)
Glucose Oxidase , Hydrogen Peroxide , Glucose
13.
Anal Chem ; 93(31): 10744-10749, 2021 08 10.
Article in English | MEDLINE | ID: mdl-34314583

ABSTRACT

In a typical intracellular electroanalytical measurement, a nanoelectrode is located inside a living cell and a reference electrode outside the cell. This setup faces a problem to drop a certain potential across the cellular plasma membrane that might interrupt the cellular activity. To solve this problem, a self-referenced nanopipette is assembled by incorporating a reference electrode inside the nanocapillary, with a Pt ring at the tip as the electrochemical surface. The potential applied between the Pt ring and the reference electrode is restricted inside the capillary and thus has a negligible effect on the surrounding cellular environment. Using this new setup, the nanopipette pierces into the nucleus of a single living cell for the measurement of hydrogen peroxide under oxidative stress. It is found that a lesser amount of hydrogen peroxide is measured in the nucleus compared with the cytoplasm, revealing uneven oxidative stress inside the cell. The result will not only greatly improve the current setup for intracellular electrochemical analysis but also provide biological information of the compartment inside the living cell.


Subject(s)
Electrochemical Techniques , Hydrogen Peroxide , Cell Membrane , Cell Nucleus , Electrodes , HeLa Cells , Humans
14.
Analyst ; 146(18): 5528-5532, 2021 Sep 13.
Article in English | MEDLINE | ID: mdl-34515710

ABSTRACT

Conventional photoelectrochemical (PEC) analysis mostly utilizes photoactive material modified planar indium tin oxides (ITOs) to obtain photocurrent responses for the measurement of analytes in solution. In this work, a CdS quantum dot (QD) modified nanopipette was prepared for the PEC analysis of the alkaline phosphatase (ALP) activity in single MCF-7 cells. The nanopipette was filled with ascorbic acid 2-phosphate (AAP) that was egressed outside the nanopipette by electrochemical pumping. Next, AAP was catalyzed by ALP to generate ascorbic acid (AA), which is an efficient electron donor for CdS QDs under illumination. Based on the result that the nanopipette showed a linear photocurrent response to AA, a nearly linear correlation between the photocurrent and the activity of ALP was established. Accordingly, using these CdS QD modified nanopipettes, the ALP activity in single MCF-7 cells was determined to be 0.12 U mL-1 by PEC analysis. This work does not expand the application of PEC bioanalysis, but offers a new strategy for single cell analysis.


Subject(s)
Biosensing Techniques , Quantum Dots , Alkaline Phosphatase , Electrochemical Techniques
15.
Proc Natl Acad Sci U S A ; 115(16): 4087-4092, 2018 04 17.
Article in English | MEDLINE | ID: mdl-29610324

ABSTRACT

The protein activity in individual intracellular compartments in single living cells must be analyzed to obtain an understanding of protein function at subcellular locations. The current methodology for probing activity is often not resolved to the level of an individual compartment, and the results provide an extent of reaction that is averaged from a group of compartments. To address this technological limitation, a single lysosome is sorted from a living cell via electrophoresis into a nanocapillary designed to electrochemically analyze internal solution. The activity of a protein specific to lysosomes, ß-glucosidase, is determined by the electrochemical quantification of hydrogen peroxide generated from the reaction with its substrate and the associated enzymes preloaded in the nanocapillary. Sorting and assaying multiple lysosomes from the same cell shows the relative homogeneity of protein activity between different lysosomes, whereas the protein activity in single lysosomes from different cells of the same type is heterogeneous. Thus, this study for the analysis of protein activity within targeted cellular compartments allows direct study of protein function at subcellular resolution and provides unprecedented information about the homogeneity within the lysosomal population of a single cell.


Subject(s)
Lysosomes/enzymology , Electrochemical Techniques , Glucose Oxidase/metabolism , Glucosidases , Glucosides/metabolism , Hydrogen Peroxide/analysis , Nanotubes , Single-Cell Analysis
16.
Biomed Chromatogr ; 35(3): e5006, 2021 Mar.
Article in English | MEDLINE | ID: mdl-33067853

ABSTRACT

In this study, a simple and sensitive LC-tandem mass spectrometric method was developed and validated for the determination of LNP023 in rat plasma. The plasma sample was precipitated with acetonitrile and then separated on an ACQUITY HSS T3 column (50 mm × 2.1 mm, 1.8 µm) using 0.1% formic acid in water and acetonitrile as the mobile phase. The MS detection was performed in positive multiple-reaction monitoring mode with precursor-to-product ion transitions of m/z 423.3 → 174.1 and m/z 435.3 → 367.1 for LNP023 and olaparib (internal standard), respectively. The developed assay was validated in the linear range of 0.1-1000 ng/mL with correlation coefficient (r) greater than 0.9992. The validation parameters were all within the acceptable limits. The validated method has been successfully used to investigate the pharmacokinetics of LNP023 in rat plasma, and our results indicated that LNP023 showed low clearance and high bioavailability (62.2%). Furthermore, four minor metabolites from rat plasma were detected and identified by LC combined with high-resolution mass spectrometry. The metabolic pathways were O-deethylation (M1), hydroxylation (M4), oxidation (M3), and acyl-glucuronidation (M2).


Subject(s)
Benzoates/blood , Benzoates/pharmacokinetics , Chromatography, Liquid/methods , Piperidines/blood , Piperidines/pharmacokinetics , Animals , Benzoates/chemistry , Biological Availability , Complement Factor B/antagonists & inhibitors , Linear Models , Male , Piperidines/chemistry , Rats , Rats, Sprague-Dawley , Reproducibility of Results , Sensitivity and Specificity , Tandem Mass Spectrometry/methods
17.
J Am Chem Soc ; 142(12): 5778-5784, 2020 03 25.
Article in English | MEDLINE | ID: mdl-32119540

ABSTRACT

Resistive-pulse sensing is a technique widely used to detect single nanoscopic entities such as nanoparticles and large molecules that can block the ion current flow through a nanopore or a nanopipette. Although the species of interest, e.g., antibodies, DNA, and biological vesicles, are typically produced by living cells, so far, they have only been detected in the bulk solution since no localized resistive-pulse sensing in biological systems has yet been reported. In this report, we used a nanopipette as a scanning ion conductance microscopy (SICM) tip to carry out resistive-pulse experiments both inside immobilized living cells and near their surfaces. The characteristic changes in the ion current that occur when the pipet punctures the cell membrane are used to monitor its insertion into the cell cytoplasm. Following the penetration, cellular vesicles (phagosomes, lysosomes, and/or phagolysosomes) were detected inside a RAW 264.7 macrophage. Much smaller pipettes were used to selectively detect 10 nm Au nanoparticles in the macrophage cytoplasm. The in situ resistive-pulse detection of extracellular vesicles released by metastatic human breast cells (MDA-MB-231) is also demonstrated. Electrochemical resistive-pulse experiments were carried out by inserting a conductive carbon nanopipette into a macrophage cell to sample single vesicles and measure reactive oxygen and nitrogen species (ROS/RNS) contained inside them.


Subject(s)
Lysosomes/chemistry , Metal Nanoparticles/analysis , Phagosomes/chemistry , Reactive Nitrogen Species/analysis , Reactive Oxygen Species/analysis , Animals , Cell Line, Tumor , Electrochemical Techniques/instrumentation , Electrochemical Techniques/methods , Gold/chemistry , Humans , Metal Nanoparticles/chemistry , Mice , Microscopy/instrumentation , Microscopy/methods , RAW 264.7 Cells
18.
J Nat Prod ; 83(4): 1238-1248, 2020 04 24.
Article in English | MEDLINE | ID: mdl-32223193

ABSTRACT

Seven new daphnane-type diterpenoids, daphgenkins A-G (1-7), and 15 known analogues (8-22) were isolated from the flower buds of Daphne genkwa. Their structures and absolute configurations were elucidated by spectroscopic data and calculated ECD analyses. The cytotoxicities of all daphnane-type diterpenoids (1-22) obtained were evaluated against three human colon cancer cell lines (SW620, RKO, and LoVo). Compounds 1, 12, and 13 exhibited cytotoxic effects against the SW620 and RKO cell lines, with IC50 values in the range of 3.0-9.7 µM. The most active new compound, 1, with an IC50 value of 3.0 µM against SW620 cells, was evaluated further for its underlying molecular mechanism. Compound 1 induced G0/G1 cell cycle arrest, leading to the induction of apoptosis in SW620 cells. Also, it induced cancer cell apoptosis by an increased ratio of Bax/Bcl-2, activated cleaved caspase-3 and caspase-9, and upregulated PARP. Finally, compound 1 significantly inhibited PI3K/Akt/mTOR signaling in SW620 cells. Together, the results suggest that compound 1 may be a suitable lead compound for further biological evaluation.


Subject(s)
Antineoplastic Agents/pharmacology , Colonic Neoplasms/physiopathology , Daphne/chemistry , Diterpenes/pharmacology , Proto-Oncogene Proteins c-bcl-2/metabolism , TOR Serine-Threonine Kinases/metabolism , Antineoplastic Agents/chemistry , Antineoplastic Agents/isolation & purification , Apoptosis/drug effects , Caspase 3/chemistry , Caspase 3/metabolism , Cell Cycle Checkpoints/drug effects , Colonic Neoplasms/drug therapy , Diterpenes/chemistry , Diterpenes/isolation & purification , Humans , Molecular Structure , Phosphatidylinositol 3-Kinases/chemistry , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/chemistry , Proto-Oncogene Proteins c-akt/metabolism , Proto-Oncogene Proteins c-bcl-2/chemistry , Signal Transduction/drug effects , TOR Serine-Threonine Kinases/chemistry
19.
Clin Lab ; 66(4)2020 Apr 01.
Article in English | MEDLINE | ID: mdl-32255302

ABSTRACT

BACKGROUND: To study the relationship of red cell distribution width (RDW) and N-terminal pro-brain natriuretic peptide (NT-proBNP) with the severity and prognosis of patients with acute coronary syndrome (ACS) receiving percutaneous coronary intervention (PCI). METHODS: A total of 396 patients were divided into four groups according to Gensini scores. They were divided into a major adverse cardiovascular event (MACE) group and a non-MACE group during follow-up. The baseline clinical data, blood biochemical indices, RDW, and NT-proBNP levels on the second day of admission were collected. The relationship of RDW and NT-proBNP with MACEs was analyzed by the Cox proportional hazard model, and risk stratification was conducted according to optimal cutoff values under ROC curves. RESULTS: RDW and NT-proBNP level were significantly positively correlated with Gensini score (p < 0.05). RDW and NT-proBNP level of the MACE group significantly exceeded those of the non-MACE group (p < 0.05). The AUC values of RDW and NT-proBNP level were 0.722 and 0.761, respectively. The optimal cutoff values were 31.86 and 1,486.65 pg/mL respectively. RDW of > 31.86 and NT-proBNP level of > 1,487.65 pg/mL were independent risk factors for MACEs in ACS patients. The patients were stratified according to the optimal cut-off values. Compared with the low-risk group, the MACE risks of middle-risk and high-risk groups increased 1.79-fold (p = 0.012) and 2.54-fold (p < 0.001), respectively. The patients had significantly different event-free survival rates (p < 0.001). CONCLUSIONS: RDW and NT-proBNP level were significantly correlated with the severity of ACS. They were independent predictors for MACEs in ACS patients.


Subject(s)
Acute Coronary Syndrome/surgery , Biomarkers/blood , Erythrocyte Indices , Natriuretic Peptide, Brain/blood , Peptide Fragments/blood , Percutaneous Coronary Intervention/methods , Acute Coronary Syndrome/blood , Acute Coronary Syndrome/diagnosis , Adult , Aged , Aged, 80 and over , Female , Humans , Kaplan-Meier Estimate , Male , Middle Aged , Prognosis , ROC Curve , Risk Assessment/methods , Risk Assessment/statistics & numerical data , Risk Factors , Severity of Illness Index
20.
J Am Chem Soc ; 141(50): 19555-19559, 2019 12 18.
Article in English | MEDLINE | ID: mdl-31771324

ABSTRACT

Resistive-pulse sensing with biological or solid-state nanopores and nanopipettes has been widely employed in detecting single molecules and nanoparticles. The analytical signal in such experiments is the change in ionic current caused by the molecule/particle translocation through the pipet orifice. This paper describes a new version of the resistive-pulse technique based on the use of carbon nanopipettes (CNP). The measured current is produced by electrochemical oxidation/reduction of redox molecules at the carbon surface and responds to the particle translocation. In addition to counting single entities, this technique enables qualitative and quantitative analysis of the electroactive material they contain. Using liposomes as a model system, we demonstrate the capacity of CNPs for (1) conventional resistive-pulse sensing of single liposomes, (2) electrochemical resistive-pulse sensing, and (3) electrochemical identification and quantitation of redox species (e.g., ferrocyanide, dopamine, and nitrite) contained in a single liposome. The small physical size of a CNP suggests the possibility of single-entity measurements in biological systems.

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