Histone H3 lysine 27 crotonylation mediates gene transcriptional repression in chromatin.

Histone lysine acylation, including acetylation and crotonylation, plays a pivotal role in gene transcription in health and diseases. However, our understanding of histone lysine acylation has been limited to gene transcriptional activation. Here, we report that histone H3 lysine 27 crotonylation (H3K27cr) directs gene transcriptional repression rather than activation. Specifically, H3K27cr in chromatin is selectively recognized by the YEATS domain of GAS41 in complex with SIN3A-HDAC1 co-repressors. Proto-oncogenic transcription factor MYC recruits GAS41/SIN3A-HDAC1 complex to repress genes in chromatin, including cell-cycle inhibitor p21. GAS41 knockout or H3K27cr-binding depletion results in p21 de-repression, cell-cycle arrest, and tumor growth inhibition in mice, explaining a causal relationship between GAS41 and MYC gene amplification and p21 downregulation in colorectal cancer. Our study suggests that H3K27 crotonylation signifies a previously unrecognized, distinct chromatin state for gene transcriptional repression in contrast to H3K27 trimethylation for transcriptional silencing and H3K27 acetylation for transcriptional activation.

Chemoenzymatic Oxidation of Labdane and Formal Synthesis of Nimbolide.

In nature, basic terpene skeletons are produced and subsequently undergo enzymatic or nonenzymatic oxidative transformations, leading to diverse structural variations. To date, thousands of natural products featuring a variety of oxidation patterns have been isolated solely from the labdane family. This work describes a strategy for the comprehensive introduction of oxidation states into the labdane core by employing a combination of enzyme library screening, directed evolution, and sequential chemical oxidation processes. Furthermore, we showcase the functional viability of our chemoenzymatic approach by accomplishing a formal synthesis of nimbolide, highlighting its potential for streamlining the synthesis of complex natural products.

Bis-tridentate Iridium(III) Complex with the N-Heterocyclic Carbene Ligand as a Novel Efficient Electrochemiluminescence Emitter for the Sandwich Immunoassay of the HHV-6A Virus.

Human herpesvirus type 6A (HHV-6A) can cause a series of immune and neurological diseases, and the establishment of a sensitive biosensor for the rapid detection of HHV-6A is of great significance for public health and safety. Herein, a bis-tridentate iridium complex (BisLT-Ir-NHC) comprising the N-heterocyclic carbene (NHC) ligand as a novel kind of efficient ECL luminophore has been unprecedently reported. Based on its excellent ECL properties, a new sensitive ECL-based sandwich immunosensor to detect the HHV-6A virus was successfully constructed by encapsulating BisLT-Ir-NHC into silica nanoparticles and embellishing ECL sensing interface with MXene@Au-CS. Notably, the immunosensor illustrated in this work not only had a wide linear range of 102 to 107 cps/µL but also showed outstanding recoveries (98.33-105.11%) in real human serum with an RSD of 0.85-3.56%. Undoubtedly, these results demonstrated the significant potential of the bis-tridentate iridium(III) complex containing an NHC ligand in developing ECL-based sensitive analytical methods for virus detection and exploring novel kinds of efficient iridium-based ECL luminophores in the future.

Ultrasensitive Electrochemiluminescence Biosensor to Detect Ampicillin Resistance Gene (ARGAMP) Based on a Novel Near-Infrared Ruthenium Carbene Complex/TPrA/PEI Ternary ECL System.

The establishment of rapid target identification and analysis methods for antibiotic resistance genes (ARGs) is urgently needed. In this study, we unprecedently designed a target-catalyzed hairpin assembly (CHA) electrochemiluminescent (ECL) biosensor for the ultrasensitive detection of ampicillin resistance genes (ARGAMP) based on a novel, efficient near-infrared ruthenium carbene complex/TPrA/PEI ternary ECL system with low oxidation potential. The ternary NIR-ECL system illustrated in this work displayed double ECL intensity in comparison with their corresponding traditional binary ECL system. The as-prepared ECL biosensor illustrated in this work demonstrates highly selective and sensitive determination of ARGAMP from 1 fM to 1 nM and a low detection limit of 0.23 fM. Importantly, it also exhibits good accuracy and stabilities to identify ARGAMP in plasmid and bacterial genome DNA, which demonstrates its excellent reliability and great potential in detecting ARGAMP in real environmental samples.

Novel Efficient Selenium-Based D-π-A NIR Polymer Dots Anodic Electrochemiluminescence Emitter and Its Application in Simultaneous Detection of Two Pneumonia Pathogens with CdS Quantum Dots.

Community-acquired pneumonia (CAP) is a major cause of death in children under 5 years old globally. With Streptococcus pneumoniae (S. pneumoniae) and Mycoplasma pneumoniae (M. pneumoniae) being the main pathogens linked to CAP that requires hospitalization, there is an urgent need for a straightforward, cost-efficient, and highly accurate diagnostic method for immediate and early detection of CAP. In this work, benzo[1,2-c;4,5-c']bis([1,2,5]thiadiazole) (BBT) as π-bridge spacer with the donor unit of poly(9,9-dioctylfluorene) (PF) and the acceptor unit of dithienylbenzoselenadiazole (DBS) has been successfully copolymerized to unprecedentedly prepare novel D-π-A selenium-based polymer dots with efficient NIR electrochemiluminescence (named as Se-Pdots in this work). Se-Pdots exclusively generated excellent anodic ECL in the two-component coreaction system comprising TPrA and K2S2O8. Moreover, a potential-resolved ECL biosensor to simultaneously detect S. pneumoniae and M. pneumoniae has also been successfully constructed based on this novel Se-based NIR Pdots as an anodic emitter with CdS QDs as a cathodic emitter. Under optimal conditions, the biosensor has a wide linear range for S. pneumoniae (10-15 to 10-9 M) and M. pneumoniae (10-15 to 10-9 M), with low detection limits for S. pneumoniae (0.56 fM) and M. pneumoniae (0.96 fM). The proposed ECL biosensor provides a simple, sensitive, and reliable method for the simultaneous detection of CAP pathogens in clinical applications.

Function of proprotein convertase subtilisin/kexin type 9 and its role in central nervous system diseases: An update on clinical evidence.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) has attracted lots of attention in preventing the clearance of plasma low-density lipoprotein cholesterol (LDL-C). PCSK9 inhibitors are developed to primarily reduce the cardiovascular risk by lowering LDL-C level. Recently, a number of pleiotropic extrahepatic functions of PCSK9 beyond the regulation of cholesterol metabolism, particularly its effects on central nervous system (CNS) diseases have been increasingly identified. Emerging clinical evidence have revealed that PCSK9 may play a significant role in neurocognition, depression, Alzheimer's disease, and stroke. The focus of this review is to elucidate the functions of PCSK9 and highlight the effects of PCSK9 in CNS diseases, with the aim of identifying the potential risks that may arise from low PCSK9 level (variant or inhibitor) in the clinical practice.

Characterizing atom clouds using a charge-coupled device for atom-interferometry-based G measurements.

Precise information of positions and sizes of atom clouds is required for atom-interferometry-based G measurements. In this work, characterizing atom clouds using a charge-coupled device (CCD) is presented. The parameters of atom clouds are extracted from fluorescence images captured by the CCD. For characterization, in-situ calibration of the magnification of the imaging system is implemented using the free-fall distance of atom clouds as the dimension reference. Moreover, influence of the probe beam on measuring the positions of atom clouds is investigated, and a differential measurement by reversing the direction of the probe beam is proposed to suppress the influence. Finally, precision at sub-mm level for characterizing atom clouds is achieved.

[Analysis of genetic variant in a Chinese pedigree with hereditary factor VIII deficiency].

OBJECTIVE: To explore the genetic basis for a patient with factor VIII deficiency. METHODS: All exons of the F13A1 and F13B genes were amplified by PCR and sequenced directly. The sequencing was performed with a reverse primer if a variant was found. Conservation of variant site was analyzed by the ClustalX software. Four online bioinformatic software including Mutation Taster, PolyPhen-2, PROVEAN and SIFT were used to predict the function of the mutation site. The Swiss-PdbViewer software was applied to analyze the changes in the protein model and intermolecular force. RESULTS: The proband was found to harbor a novel c.515G>C (p.Arg171Pro) variant of the F13A1 gene. The corresponding amino acid Arg171 is conserved among homologous species. Bioinformatic analysis indicated that Arg171Pro variant may affect the protein function. Protein model analysis showed that in the wild-type, there is one hydrogen bond between Arg171 and Pro27; one hydrogen bond between Arg171 and Thr28; two hydrogen bonds between Arg171 and Glu102. When Arg171 was mutated to Pro171, the three hydrogen bonds between Arg171 and Pro27, Glu102 are all disappeared and formed a new benzene ring which might affect the stability of the protein structure. No variant was found in the F13B gene. CONCLUSION: The Arg171Pro variant may account for the decreased FVIII level. Above finding has enriched the spectrum of F13A1 gene variants.

O-GlcNAcylation of MEK2 promotes the proliferation and migration of breast cancer cells.

Mitogen-activated protein kinase kinases are an important part of evolutionary conserved signaling modules that are involved in a variety of cellular processes in response to environmental stimuli. Among them, mitogen-activated protein kinase kinase 2 (MEK2) is the most crucial upstream signaling pathway of ERK1/2 cascade as a therapeutic target for overcoming Ras-driven cancers. However, the mechanisms of MEK2 regulation during tumor progression remain not fully elucidated. Herein, we identified that MEK2 was post-translationally regulated by O-GlcNAcylation. We found that MEK2 associated with OGT and was modified by O-GlcNAc. Mass spectrometry analysis further verified that O-GlcNAcylation of MEK2 occurred at Thr13, which was in the docking domain for specifically identifying its target proteins. While total O-GlcNAcylation stimulated the protein stability and phosphorylation of MEK2, Thr13 O-GlcNAcylation of MEK2 specifically enhanced its Thr394 phosphorylation as well as downstream ERK1/2 activation. Genetic ablation of MEK2 O-GlcNAcylation at Thr13 abrogated its ability to promote the proliferation and migration of breast cancer cells. Together, our data demonstrate that O-GlcNAcylation of MEK2 might be a key regulatory mechanism during tumorigenesis and is a potential therapeutic target for tumor treatment.

Spatially constrained tandem bromodomain inhibition bolsters sustained repression of BRD4 transcriptional activity for TNBC cell growth.

The importance of BET protein BRD4 in gene transcription is well recognized through the study of chemical modulation of its characteristic tandem bromodomain (BrD) binding to lysine-acetylated histones and transcription factors. However, while monovalent inhibition of BRD4 by BET BrD inhibitors such as JQ1 blocks growth of hematopoietic cancers, it is much less effective generally in solid tumors. Here, we report a thienodiazepine-based bivalent BrD inhibitor, MS645, that affords spatially constrained tandem BrD inhibition and consequently sustained repression of BRD4 transcriptional activity in blocking proliferation of solid-tumor cells including a panel of triple-negative breast cancer (TNBC) cells. MS645 blocks BRD4 binding to transcription enhancer/mediator proteins MED1 and YY1 with potency superior to monovalent BET inhibitors, resulting in down-regulation of proinflammatory cytokines and genes for cell-cycle control and DNA damage repair that are largely unaffected by monovalent BrD inhibition. Our study suggests a therapeutic strategy to maximally control BRD4 activity for rapid growth of solid-tumor TNBC cells.

FluoroTRAQ: Quantitative Analysis of Protein S-Nitrosylation through Fluorous Solid-Phase Extraction Combining with iTRAQ by Mass Spectrometry.

S-Nitrosylation is an important post-translational modification that occurs on cysteine amino acid and regulates signal transduction in diverse cell processes. Dysregulation of protein nitrosylation has shown close association with cardiovascular and neurological diseases, thus demanding further precise and in-depth understanding. Mass spectrometry-based proteomics has been the method of choice for analyzing S-nitrosylated (SNO-) proteins. However, due to their extremely low expression level and rapid turnover rate, quantitative analysis of the S-nitrosylation at the proteomic level remains challenging. Herein, we developed a novel approach termed FluoroTRAQ, which combined the fluorous solid-phase extraction of SNO-peptides and iTRAQ labeling for the quantitative analysis of the SNO-proteome with high sensitivity and specificity. This new analytical strategy was subsequently applied to examine the dynamic SNO-proteome changes of human umbilical vein endothelial cells upon in vitro S-nitrosoglutathione induction. Our data identified a number of novel SNO-proteins and revealed their temporal modulation as validated by biotin switch assay. Our study offered a practical approach for quantitative analysis of protein S-nitrosylation.

Multi-wave atom interferometer based on Doppler-insensitive Raman transition.

An atom interferometer based on Doppler-insensitive Raman transition is proposed, which has sharply peaked interference fringes for multi-wave interference. We show that two sets of counter-propagating Doppler-insensitive Raman beam pairs can be used to construct a new type of multi-wave beam splitter, which can be used to construct an atom interferometer. Although the spacing between adjacent diffraction orders of the interferometer is small, they can be distinguished by the internal state of the atom. Our analysis shows that the width of the fringes of this atom interferometer is inversely proportional to the width (duration) of the beam splitter and the Rabi frequency of the Raman beams, that is, the interferometer can achieve high resolution at high light intensity and long pulse width.

Tungsten-Catalyzed Allylic Substitution with a Heteroatom Nucleophile: Reaction Development and Synthetic Applications.

A tungsten-catalyzed allylic allylation of sodium sulfinate as the heteroatom nucleophile was developed. The reaction utilizes inexpensive and readily available (CH3CN)3W(CO)3 as a precatalyst and proceeds at 60 °C temperature in the presence of 2,2'-bipyridine and its derivatives as ligand. The synthetic utility of allylic sulfones as electrophile was further demonstrated through Suzuki-Miyaura cross-coupling as showcased by the formal synthesis of (±)-hinokiresinol.

Omipalisib Inhibits Esophageal Squamous Cell Carcinoma Growth Through Inactivation of Phosphoinositide 3-Kinase (PI3K)/AKT/Mammalian Target of Rapamycin (mTOR) and ERK Signaling.

BACKGROUND Esophageal squamous cell carcinoma (ESCC) is a life-threatening digestive tract malignancy with no known curative treatment. This study aimed to investigate the antineoplastic effects of omipalisib and its underlying molecular mechanisms in ESCC using a high throughput screen. MATERIAL AND METHODS MTT assay and clone formation were used to determine cell viability and proliferation. Flow cytometry was conducted to detect cell cycle distribution and apoptosis. Global gene expression and mRNA expression levels were determined by RNA sequencing and real-time PCR, respectively. Protein expression was evaluated in the 4 ESCC cell lines by Western blot analysis. Finally, a xenograft nude mouse model was used to evaluate the effect of omipalisib on tumor growth in vivo. RESULTS In the pilot screening of a 1404-compound library, we demonstrated that omipalisib markedly inhibited cell proliferation in a panel of ESCC cell lines. Mechanistically, omipalisib induced G0/G1 cell cycle arrest and apoptosis. RNA-seq, KEGG, and GSEA analyses revealed that the PI3K/AKT/mTOR pathway is the prominent target of omipalisib in ESCC cells. Treatment with omipalisib decreased expression of p-AKT, p-4EBP1, p-p70S6K, p-S6, and p-ERK, therefore disrupting the activation of PI3K/AKT/mTOR and ERK signaling. In the nude mouse xenograft model, omipalisib significantly suppressed the tumor growth in ESCC tumor-bearing mice without obvious adverse effects. CONCLUSIONS Omipalisib inhibited the proliferation and growth of ESCC by disrupting PI3K/AKT/mTOR and ERK signaling. The present study supports the rationale for using omipalisib as a therapeutic approach in ESCC patients. Further clinical studies are needed.

Functional Grading of a Transversely Isotropic Hyperelastic Model with Applications in Modeling Tricuspid and Mitral Valve Transition Regions.

Surgical simulators and injury-prediction human models require a combination of representative tissue geometry and accurate tissue material properties to predict realistic tool-tissue interaction forces and injury mechanisms, respectively. While biological tissues have been individually characterized, the transition regions between tissues have received limited research attention, potentially resulting in inaccuracies within simulations. In this work, an approach to characterize the transition regions in transversely isotropic (TI) soft tissues using functionally graded material (FGM) modeling is presented. The effect of nonlinearities and multi-regime nature of the TI model on the functional grading process is discussed. The proposed approach has been implemented to characterize the transition regions in the leaflet (LL), chordae tendinae (CT) and the papillary muscle (PM) of porcine tricuspid valve (TV) and mitral valve (MV). The FGM model is informed using high resolution morphological measurements of the collagen fiber orientation and tissue composition in the transition regions, and deformation characteristics predicted by the FGM model are numerically validated to experimental data using X-ray diffraction imaging. The results indicate feasibility of using the FGM approach in modeling soft-tissue transitions and has implications in improving physical representation of tissue deformation throughout the body using a scalable version of the proposed approach.

Molecular Engineering of Potent Sensitizers for Very Efficient Light Harvesting in Thin-Film Solid-State Dye-Sensitized Solar Cells.

Dye-sensitized solar cells (DSSCs) have shown significant potential for indoor and building-integrated photovoltaic applications. Herein we present three new D-A-π-A organic sensitizers, XY1, XY2, and XY3, that exhibit high molar extinction coefficients and a broad absorption range. Molecular modifications of these dyes, featuring a benzothiadiazole (BTZ) auxiliary acceptor, were achieved by introducing a thiophene heterocycle as well as by shifting the position of BTZ on the conjugated bridge. The ensuing high molar absorption coefficients enabled the fabrication of highly efficient thin-film solid-state DSSCs with only 1.3 µm mesoporous TiO2 layer. XY2 with a molar extinction coefficient of 6.66 × 10(4) M(-1) cm(-1) at 578 nm led to the best photovoltaic performance of 7.51%.

Test of the Universality of Free Fall with Atoms in Different Spin Orientations.

We report a test of the universality of free fall by comparing the gravity acceleration of the ^{87}Rb atoms in m_{F}=+1 versus those in m_{F}=-1, of which the corresponding spin orientations are opposite. A Mach-Zehnder-type atom interferometer is exploited to alternately measure the free fall acceleration of the atoms in these two magnetic sublevels, and the resultant Eötvös ratio is η_{S}=(0.2±1.2)×10^{-7}. This also gives an upper limit of 5.4×10^{-6} m^{-2} for a possible gradient field of the spacetime torsion. The interferometer using atoms in m_{F}=±1 is highly sensitive to the magnetic field inhomogeneity. A double differential measurement method is developed to alleviate the inhomogeneity influence, of which the effectiveness is validated by a magnetic field modulating experiment.

Turn-on fluorescence and unprecedented encapsulation of large aromatic molecules within a manganese(II)-triazole metal-organic confined space.

For the purpose of investigating the coordination behavior of sterically congested alkenes and exploring the possibility of cofacial complexation in the polycyclic aromatic system for the formation of extended polymeric networks, a new tetradentate ligand, 1,1,2,2-tetrakis[4-(1H-1,2,4-triazol-1-yl)phenyl]ethylene (TTPE), has been designed and synthesized. By using TTPE as a building block with regard to the self-assembly with MnCl2 ⋅4 H2 O, a novel two-dimensional coordination framework {[Mn(TTPE)Cl2 ]⋅4 CHCl3 }n (1) can be isolated. Anion-exchange and organic-group-functionalized aromatic guest TTPE-loaded host-guest complex experimental results indicate that coordinated Cl(-) anions in the 2D framework of 1 can be completely replaced with dissociative ClO4 (-) groups in an irreversible single-crystal-to-single-crystal transformation fashion, as evidenced by the anion-exchange products of {[Mn(TTPE)(H2 O)2 ](ClO4 )2 ⋅0.5 TTPE⋅5.25 H2 O}n (2). Interestingly, TTPE, acting as an organic template, was encapsulated in the confined space of the 2D grid of 2. To the best of our knowledge, such large organic molecules encapsulated in the reactive organic-group-functionalized aromatic-guest-loaded host-guest complex are unprecedented up to now. Luminescence measurements illustrate that 1 and 2 represent novel examples of sensing materials based on triazole derivatives. Further, 2 has been demonstrated by tuning the fluorescence response of porous metal-organic frameworks as a function of adsorbed small analytes.

Regularized outcome weighted subgroup identification for differential treatment effects.

To facilitate comparative treatment selection when there is substantial heterogeneity of treatment effectiveness, it is important to identify subgroups that exhibit differential treatment effects. Existing approaches model outcomes directly and then define subgroups according to interactions between treatment and covariates. Because outcomes are affected by both the covariate-treatment interactions and covariate main effects, direct modeling outcomes can be hard due to model misspecification, especially in presence of many covariates. Alternatively one can directly work with differential treatment effect estimation. We propose such a method that approximates a target function whose value directly reflects correct treatment assignment for patients. The function uses patient outcomes as weights rather than modeling targets. Consequently, our method can deal with binary, continuous, time-to-event, and possibly contaminated outcomes in the same fashion. We first focus on identifying only directional estimates from linear rules that characterize important subgroups. We further consider estimation of comparative treatment effects for identified subgroups. We demonstrate the advantages of our method in simulation studies and in analyses of two real data sets.

Anion-exchange and anthracene-encapsulation within copper(II) and manganese(II)-triazole metal-organic confined space in a single crystal-to-single crystal transformation fashion.

A new multidentate ligand 1-(9-(1H-1,2,4-triazol-1-yl)anthracen-10-yl)-1H-1,2,4-triazole (tatrz) was designed and synthesized. Using tatrz as a building block, three novel coordination frameworks, namely, {[Cu(tatrz)2(NO3)2]·(CH3OH)·4H2O}n (1), {[Cu(tatrz)2(H2O)2](BF4)2}n (2), and [Mn(tatrz)2(SCN)2(CH3OH)]·2H2O (3) can be isolated. Anion-exchange experiment indicates that NO3(-) anions in the two-dimensional (2D) copper framework of 1 can be completely exchanged by ClO4(-) in an irreversible single crystal-to-single crystal (SC-SC) transformation fashion, as evidenced by the anion-exchange products of {[Cu(tatrz)2(H2O)2](ClO4)2·4CH3OH} (1a). Further, if 1a was employed as a precursor in N,N-dimethylformamide (DMF), an isomorphic solvate of {[Cu(tatrz)2(DMF)2](ClO4)2·2H2O}n (1b) can be generated during the reversible dynamic transformation process. When 1 was immersed in CH3OH, a distinct 2D layer {[Cu(tatrz)2(NO3)2]·4.4CH3OH·0.6H2O}n (1c) was isolated. Interestingly, the solvent-exchange conversion is also invertible between 1 and 1c, which exhibits spongelike dynamic behavior with retention of crystalline integrity. If the 2-fold interpenetrating three-dimensional (3D) framework 2 is selected, it can be transformed into another 2-fold interpenetrating 3D framework {[Cu(tatrz)2(H2O)2](ClO4)2·5.56H2O}n (2a) in a reversible SC-SC transformation fashion. However, when the light yellow crystals of mononuclear complex 3 were exposed to trichloromethane containing aromatic organic anthracene (atan), through our careful observation, the crystals of 3 were dissolved and reassembled into dark brown crystals of 2D crystalline coordination framework {[Mn(tatrz)2(SCN)2]·(atan)}n (3a). X-ray diffraction revealed that in 3a, atan acting as an organic template was encapsulated in the confined space of the 2D grid. Luminescent measurements illustrate that 3a is the first report of multidimensional polymers based on triazole derivatives as luminescent probes of Mg(2+).