Your browser doesn't support javascript.
loading
: 20 | 50 | 100
1 - 20 de 27
1.
Materials (Basel) ; 17(10)2024 May 07.
Article En | MEDLINE | ID: mdl-38793243

The use of thermoplastic composites (TPCs) as one of the lightweight solutions will inevitably encounter problems in connection. Resistance welding has the characteristics of high strength, simplicity, and high reliability, and is considered a very potential hot-melt connection technology. The resistance welding technology of unidirectional carbon fiber-reinforced polyphenylene sulfide composites (UCF/PPS) was systematically studied. The experimental results show that the 100-mesh brass mesh has the best resin wetting effect and heating efficiency, and the PPS/oxidized 100-mesh brass mesh composite resistance element (Ox-RE/PPS) has the highest welding strength. The welding failure mode changes from interface failure and RE failure to interlayer structure damage and fiber fracture. The single-factor experimental results show that the maximum welding strength is reached at 310 °C, 1.15 MPa, and 120 kW/m2. According to the conclusion of the single-factor experiment, the Box-Behnken method was further used to design a three-factor, three-level experiment, and a quadratic regression model was established according to the test results. The results of variance analysis, fitting curve analysis, and perturbation plot analysis proved that the model had high fitting and prediction abilities. From the 3D surface diagram analysis, the influence of power density is the largest, and the interaction between welding temperature and power density is the most significant. Combined with the analysis of Design Expert 13 software, the optimal range of process parameters was obtained as follows: welding temperature 313-314 °C, welding pressure 1.04-1.2 MPa, and power density 124-128 kW/m2. The average strength of resistance welding joints prepared in the optimal range of process parameters was 13.58 MPa.

2.
J Med Chem ; 67(9): 7088-7111, 2024 May 09.
Article En | MEDLINE | ID: mdl-38634624

The novel metal(II)-based complexes HA-Cu, HA-Co, and HA-Ni with phenanthroline, sulfamethazine, and aromatic-aromatic coupled disulfamethazines as ligands were synthesized and characterized. HA-Cu, HA-Co, and HA-Ni all showed a broad spectrum of cytotoxicity and antiangiogenesis. HA-Cu was superior to HA-Co and HA-Ni, and even superior to DDP, showing significant inhibitory effect on the growth and development of tripe-negative breast cancer in vivo and in vitro. HA-Cu exhibited observable synergistic effects of antiproliferation, antiangiogenesis, anti-inflammatory, pro-apoptosis, and cuproptosis to effectively inhibited tumor survival and development. The molecular mechanism was confirmed that HA-Cu could downregulate the expression of key proteins in the VEGF/VEGFR2 signaling pathway and the expression of inflammatory cytokines, enhance the advantage of pro-apoptotic protein Bax, and enforce cuproptosis by weakening the expression of FDX1 and enhancing the expression of HSP70. Our research will provide a theoretical and practical reference for the development of metal-sulfamethazine and its derivatives as chemotherapy drugs for cancer treatment.


Angiogenesis Inhibitors , Antineoplastic Agents , Apoptosis , Coordination Complexes , Phenanthrolines , Triple Negative Breast Neoplasms , Apoptosis/drug effects , Humans , Coordination Complexes/pharmacology , Coordination Complexes/chemistry , Coordination Complexes/chemical synthesis , Coordination Complexes/therapeutic use , Animals , Phenanthrolines/pharmacology , Phenanthrolines/chemistry , Phenanthrolines/chemical synthesis , Female , Triple Negative Breast Neoplasms/drug therapy , Triple Negative Breast Neoplasms/pathology , Triple Negative Breast Neoplasms/metabolism , Angiogenesis Inhibitors/pharmacology , Angiogenesis Inhibitors/chemical synthesis , Angiogenesis Inhibitors/chemistry , Angiogenesis Inhibitors/therapeutic use , Antineoplastic Agents/pharmacology , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Cell Proliferation/drug effects , Mice , Cell Line, Tumor , Anti-Inflammatory Agents/pharmacology , Anti-Inflammatory Agents/chemical synthesis , Anti-Inflammatory Agents/chemistry , Drug Synergism , Structure-Activity Relationship , Mice, Inbred BALB C , Drug Screening Assays, Antitumor
3.
Brain Imaging Behav ; 2024 Feb 26.
Article En | MEDLINE | ID: mdl-38407737

We investigated abnormal functional connectivity (FC) patterns of insular subregions in patients with minimal hepatic encephalopathy (MHE) and examined their relationships with cognitive dysfunction using resting-state functional magnetic resonance imaging (fMRI). We collected resting-state fMRI data in 54 patients with cirrhosis [20 with MHE and 34 without MHE (NHE)] and 25 healthy controls. After defining six subregions of insula, we mapped whole-brain FC of the insular subregions and identified FC differences through three groups. FC of the insular subregions was correlated against clinical parameters (including venous blood ammonia level, Child-Pugh score, and cognitive score). The discrimination performance between the MHE and NHE groups was evaluated by performing a classification analysis using the FC index. Across three groups, the observed FC differences involved four insular subregions, including the left-ventral anterior insula, left-dorsal anterior insula, right-dorsal anterior insula, and left-posterior insula (P < 0.05 with false discovery rate correction). Moreover, the FC of these four insular subregions progressively attenuated from NHE to MHE. In addition, hypoconnectivity of insular subregions was correlated with the poor neuropsychological performance and the evaluated blood ammonia levels in patients (P < 0.05 with Bonferroni correction). The FC of insular subregions yielded moderate discriminative value between the MHE and NHE groups (AUC = 0.696-0.809). FC disruption of insular subregions is related to worse cognitive performance in MHE. This study extended our understanding about the neurophysiology of MHE and may assist for its diagnosis.

4.
JACS Au ; 3(8): 2257-2268, 2023 Aug 28.
Article En | MEDLINE | ID: mdl-37654579

A recurring dream of molecular recognition is to create receptors that distinguish between closely related targets with sufficient accuracy, especially in water. The more useful the targets, the more valuable the dream becomes. We now present multianionic trimeric cyclophane receptors with a remarkable ability to bind the iconic (bipyridine)3Ru(II) (with its huge range of applications) while rejecting the nearly equally iconic (phenanthroline)3Ru(II). These receptors not only selectively capture (bipyridine)3Ru(II) but also can be redox-switched to release the guest. 1D- and 2D(ROESY)-NMR spectroscopy, luminescence spectroscopy, and molecular modeling enabled this discovery. This outcome allows the control of these applications, e.g., as a photocatalyst or as a luminescent sensor, by selectively hiding or exposing (bipyridine)3Ru(II). Overall, a 3D nanometric object is selected, picked-up, and dropped-off by a discrete molecular host. The multianionic receptors protect excited states of these metal complexes from phenolate quenchers so that the initial step in photocatalytic phenolate oxidation is retarded by nearly 2 orders of magnitude. This work opens the way for (bipyridine)3Ru(II) to be manipulated in the presence of other functional nano-objects so that many of its applications can be commanded and controlled. We have a cyclophane-based toolkit that can emulate some aspects of proteins that selectively participate in cell signaling and metabolic pathways by changing shape upon environmental commands being received at a location remote from the active site.

5.
Huan Jing Ke Xue ; 44(7): 3933-3944, 2023 Jul 08.
Article Zh | MEDLINE | ID: mdl-37438292

The Tuojiang River and Fujiang River, two important tributaries of the upper reaches of the Yangtze River, have serious water pollution problems, among which nitrogen (N) and phosphorus (P) are the most important pollutants. Therefore, the aim of this study was to identify the influencing factors of water quality in different spaces and provide a scientific basis for the prevention and control of surface water pollution in the upper reaches of the Yangtze River and its tributaries. Water samples of trunk and tributaries in the Tuojiang River and Fujiang River were collected, and the spatial distribution characteristics of water N and P were analyzed. The results showed that the Tuojiang River and Fujiang River showed serious pollution of total nitrogen (TN), with a water quality worse Ⅴ-section proportion as high as 94% and 50%, respectively. Both rivers showed that TN and TP concentrations in the tributaries were higher than those in the main stream. For both rivers, total phosphorus (TP), with moderate pollution, was mainly concentrated in Ⅱ, Ⅲ, and Ⅳ class water quality, whereas the P pollution was more serious for the Fujiang River compared to that of the Fujiang River. For the Tuojiang River, nitrate nitrogen (NN) concentration from upstream to downstream showed a trend of decreasing after the first increase, with the maximum concentration of ammonium nitrogen (AN) exhibiting at the upstream site. In particular, TP concentration increased significantly after rivers flowed through a city. For the Fujiang River trunk stream, TN and NN concentration exhibited a gradually increasing trend from the middle to lower reaches. Generally, our study revealed that TN, TP, and NN in the rivers were affected by water pH and water temperature (T). Therefore, the control of N and P pollution in rivers should pay attention to the influence of water environmental factors.


Environmental Pollutants , Nitrates , Nitrogen , Nutrients , Phosphorus , Water Pollution
6.
J Transl Med ; 21(1): 204, 2023 03 17.
Article En | MEDLINE | ID: mdl-36932403

BACKGROUND: Endometrial cancer (EC) is one of the most common gynecological malignancies globally, and the development of innovative, effective drugs against EC remains a key issue. Phytoestrogen kaempferol exhibits anti-cancer effects, but the action mechanisms are still unclear. METHOD: MTT assays, colony-forming assays, flow cytometry, scratch healing, and transwell assays were used to evaluate the proliferation, apoptosis, cell cycle, migration, and invasion of both ER-subtype EC cells. Xenograft experiments were used to assess the effects of kaempferol inhibition on tumor growth. Next-generation RNA sequencing was used to compare the gene expression levels in vehicle-treated versus kaempferol-treated Ishikawa and HEC-1-A cells. A network pharmacology and molecular docking technique were applied to identify the anti-cancer mechanism of kaempferol, including the building of target-pathway network. GO analysis and KEGG pathway enrichment analysis were used to identify cancer-related targets. Finally, the study validated the mRNA and protein expression using real-time quantitative PCR, western blotting, and immunohistochemical analysis. RESULTS: Kaempferol was found to suppress the proliferation, promote apoptosis, and limit the tumor-forming, scratch healing, invasion, and migration capacities of EC cells. Kaempferol inhibited tumor growth and promotes apoptosis in a human endometrial cancer xenograft mouse model. No significant toxicity of kaempferol was found in human monocytes and normal cell lines at non-cytotoxic concentrations. No adverse effects or significant changes in body weight or organ coefficients were observed in 3-7 weeks' kaempferol-treated animals. The RNA sequencing, network pharmacology, and molecular docking approaches identified the overall survival-related differentially expressed gene HSD17B1. Interestingly, kaempferol upregulated HSD17B1 expression and sensitivity in ER-negative EC cells. Kaempferol differentially regulated PPARG expression in EC cells of different ER subtypes, independent of its effect on ESR1. HSD17B1 and HSD17B1-associated genes, such as ESR1, ESRRA, PPARG, AKT1, and AKR1C1\2\3, were involved in several estrogen metabolism pathways, such as steroid binding, 17-beta-hydroxysteroid dehydrogenase (NADP+) activity, steroid hormone biosynthesis, and regulation of hormone levels. The molecular basis of the effects of kaempferol treatment was evaluated. CONCLUSIONS: Kaempferol is a novel therapeutic candidate for EC via HSD17B1-related estrogen metabolism pathways. These results provide new insights into the efficiency of the medical translation of phytoestrogens.


Endometrial Neoplasms , Estradiol Dehydrogenases , Kaempferols , Network Pharmacology , Animals , Female , Humans , Mice , Cell Line, Tumor , Cell Proliferation , Endometrial Neoplasms/drug therapy , Endometrial Neoplasms/genetics , Estrogens/metabolism , Kaempferols/pharmacology , Molecular Docking Simulation , PPAR gamma/metabolism , Steroids/metabolism , Estradiol Dehydrogenases/metabolism
7.
Angew Chem Int Ed Engl ; 62(27): e202301900, 2023 Jul 03.
Article En | MEDLINE | ID: mdl-36959097

Developing a new strategy to improve the self-assembly efficiency of functional assemblies in a confined space and construct hybrid functional materials is a significant and fascinating endeavor. Herein, we present a highly efficient strategy for achieving the supramolecular self-assembly of well-defined metallacages in microdroplets through continuous-flow microfluidic devices. The high efficiency and versatility of this approach are demonstrated by the generation of five representative metallacages in different solvents containing water, DMF, acetonitrile, and methanol in a few minutes with nearly quantitative yields, in contrast to the yields obtained with the hour-scale reaction time in a batch reactor. A ring-opening catalytic reaction of the metallacages was selected as a model reaction for exploring supramolecular catalysis in microdroplets, whereby the catalytic yield was enhanced by 2.22-fold compared to that of the same reaction in the batch reactor. This work illustrates a new promising approach for the self-assembly of supramolecular systems.

8.
Chem Soc Rev ; 52(3): 1129-1154, 2023 Feb 06.
Article En | MEDLINE | ID: mdl-36722920

Two-dimensional metallacycles and three-dimensional metallacages constructed by coordination-driven self-assembly have attracted much attention because they exhibit unique structures and properties and are highly efficient to synthesize. Introduction of switching into supramolecular chemistry systems is a popular strategy, as switching can endow systems with reversible features that are triggered by different stimuli. Through this strategy, novel switchable metallacycles and metallacages were generated, which can be reversibly switched into different stable states with distinct characteristics by external stimuli. Switchable metallacycles and metallacages exhibit versatile structures and reversible properties and are inherently dynamic and respond to artificial signals; thus, these structures have many promising applications in a wide range of fields, such as drug delivery, data processing, pollutant removal, switchable catalysis, smart functional materials, etc. This review focuses on the design of switchable metallacycles and metallacages, their switching behaviours and mechanisms triggered by external stimuli, and the corresponding structural changes and resultant properties and functions.

9.
Chem Sci ; 13(36): 10856-10867, 2022 Sep 21.
Article En | MEDLINE | ID: mdl-36320709

Shape-switchable cyclophane hosts allow the controlled capture and release of reactive polypyridineRu(ii) complexes in water. This gives rise to a network of host-guest binding, acid-base reactions in ground and excited states, and chemical redox interconversions. In the case of (2-(2'-pyridyl)imidazole)Ru(ii) complexes, several molecular logic gate arrays of varying complexity emerge as a result. Cyclophane-induced 'off-on' switching of luminescence in neutral solution is found to originate from two features of these aromatic hosts: enhancement of radiative decay by the polarizable host and the suppression of nonradiative decay involving deprotonation by reducing the water content within the deep host cavity. These are examples of nanometric coordination chemistry/physics being controlled by inclusion in an open box. The aromatic units of the macrocycle are also responsible for the shape-switching mechanism of wall collapse/erection.

10.
Elife ; 112022 10 27.
Article En | MEDLINE | ID: mdl-36300632

Studying electrophile signaling is marred by difficulties in parsing changes in pathway flux attributable to on-target, vis-à-vis off-target, modifications. By combining bolus dosing, knockdown, and Z-REX-a tool investigating on-target/on-pathway electrophile signaling, we document that electrophile labeling of one zebrafish-Keap1-paralog (zKeap1b) stimulates Nrf2- driven antioxidant response (AR) signaling (like the human-ortholog). Conversely, zKeap1a is a dominant-negative regulator of electrophile-promoted Nrf2-signaling, and itself is nonpermissive for electrophile-induced Nrf2-upregulation. This behavior is recapitulated in human cells: (1) zKeap1b-expressing cells are permissive for augmented AR-signaling through reduced zKeap1b-Nrf2 binding following whole-cell electrophile treatment; (2) zKeap1a-expressing cells are non-permissive for AR-upregulation, as zKeap1a-Nrf2 binding capacity remains unaltered upon whole-cell electrophile exposure; (3) 1:1 ZKeap1a:zKeap1b-co-expressing cells show no Nrf2-release from the Keap1-complex following whole-cell electrophile administration, rendering these cells unable to upregulate AR. We identified a zKeap1a-specific point-mutation (C273I) responsible for zKeap1a's behavior during electrophilic stress. Human-Keap1(C273I), of known diminished Nrf2-regulatory capacity, dominantly muted electrophile-induced Nrf2-signaling. These studies highlight divergent and interdependent electrophile signaling behaviors, despite conserved electrophile sensing.


NF-E2-Related Factor 2 , Zebrafish , Animals , Humans , Kelch-Like ECH-Associated Protein 1/genetics , Kelch-Like ECH-Associated Protein 1/metabolism , NF-E2-Related Factor 2/genetics , NF-E2-Related Factor 2/metabolism , Zebrafish/metabolism , Antioxidants/metabolism , Signal Transduction
11.
Front Neurol ; 13: 922677, 2022.
Article En | MEDLINE | ID: mdl-35795802

Background: The relationship between mortality and seizures after intracerebral hemorrhage (ICH) has not yet been understood until now. A meta-analysis was performed to assess the effect of post-ICH seizures on mortality among patients with ICH. Methods: PubMed and Embase were searched from the establishment of the databases to December 2021 to identify literature that evaluated the relationship between post-ICH seizures and mortality in ICH. Crude odds ratios and adjusted odds ratios with a 95% confidence interval (CI) were pooled using a random-effects model. Results: Thirteen studies involving 245,908 participants were eventually included for analysis. The pooled estimate suggested that post-ICH seizures were not associated with significantly increased mortality in patients with ICH (crude odds ratios 1.35, 95% CI: 0.91-2; adjusted adds ratios 1.22, 95% CI: 0.78-1.88). However, the relationship was not consistent in subgroup analysis or robust in a sensitivity analysis. Conclusions: This meta-analysis proved that post-ICH seizures were not associated with significantly increased mortality in patients with ICH. However, this result could be influenced by confounding factors, so more high-quality research is needed.

12.
Chem Asian J ; 16(23): 3805-3816, 2021 Dec 01.
Article En | MEDLINE | ID: mdl-34529337

The utilization of photocatalytic techniques for achieving light-to-fuel conversion is a promising way to ease the shortage of energy and degradation of the ecological environment. Fluorescent metallacycles and metallacages have drawn considerable attention and have been used in widespread fields due to easy preparation and their abundant functionality including photocatalysis. This review covers recent advances in photocatalysis in discrete supramolecular fluorescent metallacycles and metallacages. The developments in the utilization of the metallacycles skeletons and the effect of fluorescence-resonance energy transfer for photocatalysis are discussed. Furthermore, the use of the ligands decorated by organic chromophores or redox metal sites in metallacages as photocatalysts and their ability to encapsulate appropriate catalytic cofactors for photocatalysis are summarized. For the sake of brevity, macrocycles and cages with inorganic coordination complexes such as ruthenium complexes and iridium complexes are not included in this minireview.


Fluorescent Dyes/chemistry , Organometallic Compounds/chemistry , Catalysis , Energy Transfer , Macromolecular Substances/chemistry , Molecular Structure , Photochemical Processes
13.
Medicine (Baltimore) ; 100(48): e27852, 2021 Dec 03.
Article En | MEDLINE | ID: mdl-35049186

ABSTRACT: Studies on the relationship between hospital annualized case volume and in-hospital mortality in patients with subarachnoid hemorrhage (SAH) have shown conflicting results. Therefore, we performed a meta-analysis to further examine this relationship.The authors searched the PubMed and Embase databases from inception through July 2020 to identify studies that assessed the relationship between hospital annualized SAH case volume and in-hospital SAH mortality. Studies that reported in-hospital mortality in SAH patients and an adjusted odds ratio (OR) comparing mortality between low-volume and high-volume hospitals or provided core data to calculate an adjusted OR were eligible for inclusion. No language or human subject restrictions were imposed.Five retrospective cohort studies with 46,186 patients were included for analysis. The pooled estimate revealed an inverse relationship between annualized case volume and in-hospital mortality (OR, 0.53; 95% confidence interval, 0.42-0.68, P < .0001). This relationship was consistent in almost all subgroup analyses and was robust in sensitivity analyses.This meta-analysis confirms an inverse relationship between hospital annualized SAH case volume and in-hospital SAH mortality. Higher annualized case volume was associated with lower in-hospital mortality.


Hospitals, High-Volume/statistics & numerical data , Subarachnoid Hemorrhage/mortality , Hospital Mortality , Humans , Odds Ratio , Retrospective Studies
14.
Polymers (Basel) ; 12(9)2020 Sep 03.
Article En | MEDLINE | ID: mdl-32899234

Superhydrophilic coatings have been widely used for the surface modification of membranes or biomedical devices owing to their excellent antifouling properties. However, simplifying the modification processes of such materials remains challenging. In this study, we developed a simple and rapid one-step co-deposition process using an oxidant trigger to fabricate superhydrophilic surfaces based on dopamine chemistry with sulfobetaine methacrylate (SBMA). We studied the effect of different oxidants and SBMA concentrations on surface modification in detail using UV-VIS spectrophotometry, dynamic light scattering, atomic force microscopy, X-ray photoelectron spectroscopy, and surface plasmon resonance. We found that NaIO4 could trigger the rate of polymerization and the optimum ratio of dopamine to SBMA is 1:25 by weight. This makes the surface superhydrophilic (water contact angle < 10°) and antifouling. The superhydrophilic coating, when introduced to polyester membranes, showed great potential for oil/water separation. Our study provides a complete description of the simple and fast preparation of superhydrophilic coatings for surface modification based on mussel-inspired chemistry.

15.
Biochemistry ; 57(2): 216-220, 2018 01 16.
Article En | MEDLINE | ID: mdl-28857552

Adduction of an electrophile to privileged sensor proteins and the resulting phenotypically dominant responses are increasingly appreciated as being essential for metazoan health. Functional similarities between the biological electrophiles and electrophilic pharmacophores commonly found in covalent drugs further fortify the translational relevance of these small-molecule signals. Genetically encodable or small-molecule-based fluorescent reporters and redox proteomics have revolutionized the observation and profiling of cellular redox states and electrophile-sensor proteins, respectively. However, precision mapping between specific redox-modified targets and specific responses has only recently begun to be addressed, and systems tractable to both genetic manipulation and on-target redox signaling in vivo remain largely limited. Here we engineer transgenic Caenorhabditis elegans expressing functional HaloTagged fusion proteins and use this system to develop a generalizable light-controlled approach to tagging a prototypical electrophile-sensor protein with native electrophiles in vivo. The method circumvents issues associated with low uptake/distribution and toxicity/promiscuity. Given the validated success of C. elegans in aging studies, this optimized platform offers a new lens with which to scrutinize how on-target electrophile signaling influences redox-dependent life span regulation.


Caenorhabditis elegans Proteins/analysis , Caenorhabditis elegans/metabolism , Aldehydes/chemistry , Animals , Animals, Genetically Modified , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Caenorhabditis elegans/ultrastructure , Caenorhabditis elegans Proteins/genetics , Electrochemistry , Hydrolases/chemistry , Hydrolases/genetics , Kelch-Like ECH-Associated Protein 1/chemistry , Kelch-Like ECH-Associated Protein 1/genetics , Longevity , Luminescent Proteins/analysis , Luminescent Proteins/chemistry , Luminescent Proteins/genetics , Oxidation-Reduction , Photochemistry , Protein Processing, Post-Translational , Recombinant Fusion Proteins/chemistry , Recombinant Fusion Proteins/genetics , Transgenes , Red Fluorescent Protein
16.
Cell Chem Biol ; 24(8): 944-957.e7, 2017 Aug 17.
Article En | MEDLINE | ID: mdl-28736239

Simultaneous hyperactivation of Wnt and antioxidant response (AR) are often observed during oncogenesis. However, it remains unclear how the ß-catenin-driven Wnt and the Nrf2-driven AR mutually regulate each other. The situation is compounded because many players in these two pathways are redox sensors, rendering bolus redox signal-dosing methods uninformative. Herein we examine the ramifications of single-protein target-specific AR upregulation in various knockdown lines. Our data document that Nrf2/AR strongly inhibits ß-catenin/Wnt. The magnitude and mechanism of this negative regulation are dependent on the direct interaction between ß-catenin N terminus and ß-TrCP1 (an antagonist of both Nrf2 and ß-catenin), and independent of binding between Nrf2 and ß-TrCP1. Intriguingly, ß-catenin positively regulates AR. Because AR is a negative regulator of Wnt regardless of ß-catenin N terminus, this switch of function is likely sufficient to establish a new Wnt/AR equilibrium during tumorigenesis.


Wnt Proteins/metabolism , beta-Transducin Repeat-Containing Proteins/metabolism , Aldehydes/toxicity , Antioxidants/chemistry , Antioxidants/metabolism , Glycogen Synthase Kinase 3 beta/antagonists & inhibitors , Glycogen Synthase Kinase 3 beta/genetics , Glycogen Synthase Kinase 3 beta/metabolism , HEK293 Cells , HeLa Cells , Humans , Kelch-Like ECH-Associated Protein 1/chemistry , Kelch-Like ECH-Associated Protein 1/metabolism , NF-E2-Related Factor 2/antagonists & inhibitors , NF-E2-Related Factor 2/metabolism , PTEN Phosphohydrolase/antagonists & inhibitors , PTEN Phosphohydrolase/genetics , PTEN Phosphohydrolase/metabolism , Protein Binding , Protein Isoforms/antagonists & inhibitors , Protein Isoforms/genetics , Protein Isoforms/metabolism , RNA Interference , RNA, Small Interfering/metabolism , Wnt Signaling Pathway/drug effects , beta Catenin/antagonists & inhibitors , beta Catenin/metabolism , beta-Transducin Repeat-Containing Proteins/antagonists & inhibitors , beta-Transducin Repeat-Containing Proteins/genetics
17.
Nat Protoc ; 11(12): 2328-2356, 2016 Dec.
Article En | MEDLINE | ID: mdl-27809314

This protocol describes targetable reactive electrophiles and oxidants (T-REX)-a live-cell-based tool designed to (i) interrogate the consequences of specific and time-resolved redox events, and (ii) screen for bona fide redox-sensor targets. A small-molecule toolset comprising photocaged precursors to specific reactive redox signals is constructed such that these inert precursors specifically and irreversibly tag any HaloTag-fused protein of interest (POI) in mammalian and Escherichia coli cells. Syntheses of the alkyne-functionalized endogenous reactive signal 4-hydroxynonenal (HNE(alkyne)) and the HaloTag-targetable photocaged precursor to HNE(alkyne) (also known as Ht-PreHNE or HtPHA) are described. Low-energy light prompts photo-uncaging (t1/2 <1-2 min) and target-specific modification. The targeted modification of the POI enables precisely timed and spatially controlled redox events with no off-target modification. Two independent pathways are described, along with a simple setup to functionally validate known targets or discover novel sensors. T-REX sidesteps mixed responses caused by uncontrolled whole-cell swamping with reactive signals. Modification and downstream response can be analyzed by in-gel fluorescence, proteomics, qRT-PCR, immunofluorescence, fluorescence resonance energy transfer (FRET)-based and dual-luciferase reporters, or flow cytometry assays. T-REX targeting takes 4 h from initial probe treatment. Analysis of targeted redox responses takes an additional 4-24 h, depending on the nature of the pathway and the type of readouts used.


Cytological Techniques/methods , Signal Transduction , Aldehydes/metabolism , Amino Acid Sequence , Blotting, Western , Cell Survival , Escherichia coli/cytology , HEK293 Cells , Humans , Kinetics , Oxidants/metabolism , Oxidation-Reduction
18.
J Am Chem Soc ; 137(19): 6232-44, 2015 May 20.
Article En | MEDLINE | ID: mdl-25909755

Despite the known propensity of small-molecule electrophiles to react with numerous cysteine-active proteins, biological actions of individual signal inducers have emerged to be chemotype-specific. To pinpoint and quantify the impacts of modifying one target out of the whole proteome, we develop a target-protein-personalized "electrophile toolbox" with which specific intracellular targets can be selectively modified at a precise time by specific reactive signals. This general methodology, T-REX (targetable reactive electrophiles and oxidants), is established by (1) constructing a platform that can deliver a range of electronic and sterically different bioactive lipid-derived signaling electrophiles to specific proteins in cells; (2) probing the kinetics of targeted delivery concept, which revealed that targeting efficiency in cells is largely driven by initial on-rate of alkylation; and (3) evaluating the consequences of protein-target- and small-molecule-signal-specific modifications on the strength of downstream signaling. These data show that T-REX allows quantitative interrogations into the extent to which the Nrf2 transcription factor-dependent antioxidant response element (ARE) signaling is activated by selective electrophilic modifications on Keap1 protein, one of several redox-sensitive regulators of the Nrf2-ARE axis. The results document Keap1 as a promiscuous electrophile-responsive sensor able to respond with similar efficiencies to discrete electrophilic signals, promoting comparable strength of Nrf2-ARE induction. T-REX is also able to elicit cell activation in cases in which whole-cell electrophile flooding fails to stimulate ARE induction prior to causing cytotoxicity. The platform presents a previously unavailable opportunity to elucidate the functional consequences of small-molecule-signal- and protein-target-specific electrophilic modifications in an otherwise unaffected cellular background.


Intracellular Signaling Peptides and Proteins/metabolism , NF-E2-Related Factor 2/metabolism , Signal Transduction , Alkylation , HEK293 Cells , Humans , Intracellular Signaling Peptides and Proteins/analysis , Kelch-Like ECH-Associated Protein 1 , Models, Molecular , NF-E2-Related Factor 2/analysis , Oxidation-Reduction
19.
Surgeon ; 13(4): 230-40, 2015 Aug.
Article En | MEDLINE | ID: mdl-25661677

BACKGROUND & PURPOSE: Malignant middle cerebral artery infarctions (mMCAI) are one of the most devastating ischemic strokes, with up to 80% mortality in non-surgically treated patients. With the publication of three European randomized controlled trials (RCTs), decompressive hemicraniectomy (DHC) was recommended in patients with mMCAI who are aged ≤ 60 years. Recently, three other RCTs enrolling patients aged > 60 years were published; thus, it is necessary to update the previous meta-analysis to re-evaluate the effects of DHC in mMCAI. METHODS: A systematic literature search of PubMed, EMBASE, and the Cochrane Library was conducted for published RCTs investigating the effects of DHC in mMCAI. Primary outcomes were mortality and major disability (modified Rankin Scale score: 4-5) among survivors. Secondary outcomes were death or major disability (mRS score > 3), and death or severe disability (mRS score > 4). Effect sizes were expressed in Peto odds ratio (Peto OR) with 95% confidence intervals. RESULTS: Six studies with 314 patients were subjected to meta-analysis. Data showed that DHC, significantly decreased mortality risk, death or major disability (mRS score > 3), and death or severe disability (mRS score > 4); but was associated with a slightly higher proportion of major disability (mRS score: 4-5) among survivors. There were no statistically significant age differences. CONCLUSIONS: Compared to conservative treatment, DHC significantly decreased mortality and improved functional outcome, with a non-significant increase in the proportion of survivors with major disability. Further studies are required for multidimensional evaluation of DHC for mMCAI.


Brain Edema/surgery , Craniotomy/methods , Infarction, Middle Cerebral Artery/surgery , Intracranial Hypertension/surgery , Brain Edema/etiology , Decompression, Surgical , Humans , Infarction, Middle Cerebral Artery/complications , Infarction, Middle Cerebral Artery/mortality , Intracranial Hypertension/etiology , Stroke/etiology , Treatment Outcome
20.
J Am Chem Soc ; 137(1): 10-3, 2015 Jan 14.
Article En | MEDLINE | ID: mdl-25544059

Lipid-derived electrophiles (LDEs) that can directly modify proteins have emerged as important small-molecule cues in cellular decision-making. However, because these diffusible LDEs can modify many targets [e.g., >700 cysteines are modified by the well-known LDE 4-hydroxynonenal (HNE)], establishing the functional consequences of LDE modification on individual targets remains devilishly difficult. Whether LDE modifications on a single protein are biologically sufficient to activate discrete redox signaling response downstream also remains untested. Herein, using T-REX (targetable reactive electrophiles and oxidants), an approach aimed at selectively flipping a single redox switch in cells at a precise time, we show that a modest level (∼34%) of HNEylation on a single target is sufficient to elicit the pharmaceutically important antioxidant response element (ARE) activation, and the resultant strength of ARE induction recapitulates that observed from whole-cell electrophilic perturbation. These data provide the first evidence that single-target LDE modifications are important individual events in mammalian physiology.


Aldehydes/metabolism , Antioxidants/metabolism , Proteins/metabolism , Aldehydes/chemistry , Antioxidants/chemistry , HEK293 Cells , Humans , Models, Molecular , Molecular Structure , Oxidative Stress , Proteins/chemistry
...