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1.
Proc Natl Acad Sci U S A ; 120(1): e2211297120, 2023 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-36574664

RESUMO

WD repeat domain 5 (WDR5) is a core scaffolding component of many multiprotein complexes that perform a variety of critical chromatin-centric processes in the nucleus. WDR5 is a component of the mixed lineage leukemia MLL/SET complex and localizes MYC to chromatin at tumor-critical target genes. As a part of these complexes, WDR5 plays a role in sustaining oncogenesis in a variety of human cancers that are often associated with poor prognoses. Thus, WDR5 has been recognized as an attractive therapeutic target for treating both solid and hematological tumors. Previously, small-molecule inhibitors of the WDR5-interaction (WIN) site and WDR5 degraders have demonstrated robust in vitro cellular efficacy in cancer cell lines and established the therapeutic potential of WDR5. However, these agents have not demonstrated significant in vivo efficacy at pharmacologically relevant doses by oral administration in animal disease models. We have discovered WDR5 WIN-site inhibitors that feature bicyclic heteroaryl P7 units through structure-based design and address the limitations of our previous series of small-molecule inhibitors. Importantly, our lead compounds exhibit enhanced on-target potency, excellent oral pharmacokinetic (PK) profiles, and potent dose-dependent in vivo efficacy in a mouse MV4:11 subcutaneous xenograft model by oral dosing. Furthermore, these in vivo probes show excellent tolerability under a repeated high-dose regimen in rodents to demonstrate the safety of the WDR5 WIN-site inhibition mechanism. Collectively, our results provide strong support for WDR5 WIN-site inhibitors to be utilized as potential anticancer therapeutics.


Assuntos
Peptídeos e Proteínas de Sinalização Intracelular , Neoplasias , Repetições WD40 , Animais , Humanos , Camundongos , Cromatina , Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Modelos Animais , Neoplasias/tratamento farmacológico , Linhagem Celular Tumoral
2.
J Lipid Res ; 63(1): 100156, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34843683

RESUMO

N-acyl-phosphatidylethanolamine (NAPE)-hydrolyzing phospholipase D (NAPE-PLD) is a zinc metallohydrolase enzyme that converts NAPEs to bioactive N-acyl-ethanolamides. Altered NAPE-PLD activity may contribute to pathogenesis of obesity, diabetes, atherosclerosis, and neurological diseases. Selective measurement of NAPE-PLD activity is challenging, however, because of alternative phospholipase pathways for NAPE hydrolysis. Previous methods to measure NAPE-PLD activity involved addition of exogenous NAPE followed by TLC or LC/MS/MS, which are time and resource intensive. Recently, NAPE-PLD activity in cells has been assayed using the fluorogenic NAPE analogs PED-A1 and PED6, but these substrates also detect the activity of serine hydrolase-type lipases PLA1 and PLA2. To create a fluorescence assay that selectively measured cellular NAPE-PLD activity, we synthesized an analog of PED-A1 (flame-NAPE) where the sn-1 ester bond was replaced with an N-methyl amide to create resistance to PLA1 hydrolysis. Recombinant NAPE-PLD produced fluorescence when incubated with either PED-A1 or flame-NAPE, whereas PLA1 only produced fluorescence when incubated with PED-A1. Furthermore, fluorescence in HepG2 cells using PED-A1 could be partially blocked by either biothionol (a selective NAPE-PLD inhibitor) or tetrahydrolipstatin (an inhibitor of a broad spectrum of serine hydrolase-type lipases). In contrast, fluorescence assayed in HepG2 cells using flame-NAPE could only be blocked by biothionol. In multiple cell types, the phospholipase activity detected using flame-NAPE was significantly more sensitive to biothionol inhibition than that detected using PED-A1. Thus, using flame-NAPE to measure phospholipase activity provides a rapid and selective method to measure NAPE-PLD activity in cells and tissues.


Assuntos
Fosfatidiletanolaminas
3.
Nano Lett ; 18(10): 6301-6311, 2018 10 10.
Artigo em Inglês | MEDLINE | ID: mdl-30240228

RESUMO

Efficient small interfering RNA (siRNA) delivery in the presence of serum is of crucial importance for effective gene therapy. Fluorinated vectors are considered to be attractive candidates for siRNA-mediated gene therapy because of their delivery efficacy in serum-containing media. However, the mechanisms driving the superior gene transfection behavior of fluorinated vectors are still not well-understood, and comprehensive investigations are warranted. Herein, we fabricated a library of perfluorooctanoyl fluoride-fluorinated (PFF-fluorinated) oligoethylenimines (f xOEIs, x is the PFF:OEI feeding ratio), which can readily form nanoassemblies (f xOEI NAs) capable of efficient siRNA delivery in cells cultured in medium both devoid of and supplemented with fetal bovine serum (FBS). The gene silencing test in serum-containing medium revealed that the f0.7OEI/siRNA NAs achieved a luciferase silencing of ∼88.4% in Luc-HeLa cells cultured in FBS-containing medium, which was almost 2-fold greater than the silencing efficacy of siRNA delivered by the commercially available vector Lipo 2000 (∼48.8%). High levels of apolipoprotein B silencing were also achieved by f0.7OEI/siRNA NAs in vivo. For an assessment of the underlying mechanisms of the efficacy of gene silencing of fluorinated vectors, two alkylated OEIs, aOEI-C8 and aOEI-C12, were fabricated as controls with similar molecular structure and hydrophobicity to that of f0.7OEI, respectively. In vitro investigations showed that the superior gene delivery exhibited by f0.7OEI NAs derived from the potent endosomal disruption capability of fluorinated vectors in the presence of serum, which was essentially attributed to the serum protein adsorption resistance of the f0.7OEI NAs. Therefore, this work provides an innovative approach to siRNA delivery as well as insights into fluorine-associated serum resistance.

4.
Cell Mol Biol Lett ; 23: 43, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30202418

RESUMO

BACKGROUND: Lnc-DC is a specific group of long non-coding (Lnc) RNAs in dendritic cells (DCs). Its function has been previously studied, and includes roles in dendritic cell differentiation and the progression of some diseases. In this study, we observed the critical role of Lnc-DC in regulating the differentiation, growth, and apoptosis of dendritic cells. METHODS: We first isolated peripheral blood mononuclear cells to culture and induce into DCs, which were then co-cultured with hepatitis B virus (HBV)-secreting HepG2.2.15 cells for the detection of changes in Lnc-DC. The expression levels of TLR9, p-STAT3, and SOCS3 were tested with qPCR and western blot. MTT assays were used to analyze the cell proliferation, cell cycle, and apoptosis. We used ELISA to test the expression of TNF-α, IL-1ß, IL-6, IL-12p40, and IFN-γ. RESULTS: Co-culture with HBV-secreting HepG2.2.15 cells increased the level of Lnc-DC and activated TLR9/STAT3 signaling. The HBV DNA level (IU/ml) was positively correlated with levels of Lnc-DC and TLR9, further demonstrating that Lnc-DC was associated with the immune response of HBV. Lnc-DC was shown to regulate TLR9/STAT3 signaling in dendritic cells. More interestingly, the regulation of Lnc-DC controlled the immune response by reducing the concentration of secreted TNF-α, IL-6, IL-12, and IFN-γ, as well as increasing the IL-1ß concentration in dendritic cells. CONCLUSION: Lnc-DC is important in regulating the growth, apoptosis, and immune response of dendritic cells mediated by TLR9/STAT3 signaling, and was also activated by HBV. This study provides a previously unidentified mechanism underlying the immune response in dendritic cells.


Assuntos
Células Dendríticas/imunologia , Vírus da Hepatite B/imunologia , Hepatite B/imunologia , RNA Longo não Codificante/imunologia , Fator de Transcrição STAT3/imunologia , Transdução de Sinais , Receptor Toll-Like 9/imunologia , Apoptose , Proliferação de Células , Células Cultivadas , Células Dendríticas/citologia , Células Dendríticas/virologia , Células Hep G2 , Humanos
5.
Tetrahedron Lett ; 59(52): 4571-4573, 2018 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-30906077

RESUMO

Linoleate triol esters are intermediates along the pathway of formation of the mammalian skin permeability barrier. In connection with the study of their involvement in barrier formation we required access to isomerically pure and defined samples of four linoleate triol esters. A common synthetic strategy was developed starting from isomeric alkynols derived from d-tartaric acid and 2-deoxy-d-ribose.

6.
Appl Opt ; 57(36): 10480-10484, 2018 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-30645392

RESUMO

Photonic Doppler velocimetry (PDV) has become a major domain velocity measurement technique for shock physics experiments. In this study, we propose and validate a bi-fiber quasi-axis probe for PDV that consists of a multimode source fiber and a single-mode detection fiber. This structure makes the received light by the probe totally reflected or scattered from the target, and, therefore, is free from the influence of unwanted return light. The light-receiving efficiency of the probe was calculated by the Monte Carlo method and was validated by static experiment. We validate that the feasibility of probe by dynamic experiments with measurement depth up to 6 cm. Above all, the bi-fiber quasi-axis probe is a promising supplementary probe for PDV for shock physics experiments.

7.
BMC Plant Biol ; 16: 71, 2016 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-27000872

RESUMO

BACKGROUND: Yield of rapeseed is determined by three components: silique number, seed number per silique and thousand seed weight. Seed number per silique and thousand seed weight are influenced by silique length, seed density, silique breadth, silique thickness and silique volume. Some QTLs for silique traits have been reported in B. napus, however, no studies have focused on the six agronomic traits (seed number per silique, silique length, silique breadth, silique thickness, seed density and silique volume) simultaneously, and the genetic determinism of such complex traits have not been fully elucidated. RESULTS: In this study, the six silique traits were evaluated using 348 lines of a doubled haploid population, the KN population. The results showed that 2, 4, 1, 1 and 2 QTLs explaining > 10 % of phenotypic variation were obtained for silique length, silique breadth, silique thickness, seed number per silique and silique volume, respectively. Notably, three major effect QTLs (cqSB-C6-1, cqSB-C6-2 and cqSV-C6-3) were identified in at least three environments, and 17 unique QTLs controlling at least two traits were obtained. A high-density consensus map containing 1225 markers was constructed for QTL comparison by combining the KN map with other five published maps. The comparative results revealed that 14, 13 and 11 QTLs for silique breadth, silique thickness and silique volume might be the potential new QTLs because few QTLs for these traits were reported in B. napus. In addition, potential new QTLs for silique length (11), seed number per silique (6) and seed density (5) were also identified. Twenty-five candidate genes underlying 27 QTLs for silique related traits were obtained. CONCLUSIONS: This study constructed QTL analysis in B. napus, and obtained 60 consensus QTLs for six silique related traits. The potential new QTLs will enhance our understanding of the genetic control of silique traits, and the stable QTLs provided the targets for improving seed yield in future. These findings provided comprehensive insights into the genetic network affecting silique traits at QTL level in B. napus.


Assuntos
Brassica napus/genética , Genoma de Planta , Locos de Características Quantitativas , Sementes , Brassica napus/anatomia & histologia , Brassica napus/crescimento & desenvolvimento , Pleiotropia Genética , Variação Genética , Sementes/anatomia & histologia , Sementes/genética
8.
Theor Appl Genet ; 128(6): 1175-92, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25796183

RESUMO

KEY MESSAGE: This report describes a dynamic QTL analysis for plant height at various stages using a large doubled haploid population and performs a QTL comparison between different populations in Brassica napus. Plant height (PH) not only plays an important role in determining plant architecture, but is also an important character related to yield. The process of determining PH occurs through a series of steps; however, no studies have focused on developmental behavior factors affecting PH in Brassica napus. In the present study, KN DH, a large doubled haploid population containing 348 lines was used for a dynamic quantitative trait locus (QTL) analysis for PH in six experiments. In all, 20 QTLs were identified at maturity, whereas 50 QTLs were detected by conditional m apping method and the same number was identified by unconditional mapping strategies. Interestingly, five unconditional QTLs ucPH.A2-2, ucPH.A3-2, ucPH.C5-1, ucPH.C6-2 and ucPH.C6-3 were identified that were consistent over the all growth stages of one or two particular experiments, and one conditional QTL cPH.A2-3 was expressed throughout the entire growth process in one experiment. A total of 70 QTLs were obtained after combining QTLs identified at maturity, by conditional and unconditional mapping strategies, in which 25 showed opposite genetic effects in different periods/stages and experiments. A consensus map containing 1357 markers was constructed to compare QTLs identified in the KN population with five previously mapped populations. Alignment of the QTLs detected in different populations onto the consensus map showed that 27 were repeatedly detected in different genetic backgrounds. These findings will enhance our understanding of the genetic control of PH regulation in B. napus, and will be useful for rapeseed genetic manipulation through molecular marker-assisted selection.


Assuntos
Brassica napus/genética , Mapeamento Cromossômico , Locos de Características Quantitativas , Brassica napus/crescimento & desenvolvimento , Genética Populacional , Haploidia , Modelos Genéticos , Fenótipo , Característica Quantitativa Herdável
9.
J Proteome Res ; 12(11): 4965-78, 2013 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-24053668

RESUMO

Ultrastructural observations, combined with proteomic and comparative genomic analyses, were applied to interpret the differences in protein composition and oil-body characteristics of mature seed of two Brassica napus lines with high and low oil contents of 55.19% and 36.49%, respectively. The results showed that oil bodies were arranged much closer in the high than in the low oil content line, and differences in cell size and thickness of cell walls were also observed. There were 119 and 32 differentially expressed proteins (DEPs) of total and oil-body proteins identified. The 119 DEPs of total protein were mainly involved in the oil-related, dehydration-related, storage and defense/disease, and some of these may be related to oil formation. The DEPs involved with dehydration-related were both detected in total and oil-body proteins for high and low oil lines and may be correlated with the number and size of oil bodies in the different lines. Some genes that corresponded to DEPs were confirmed by quantitative trait loci (QTL) mapping analysis for oil content. The results revealed that some candidate genes deduced from DEPs were located in the confidence intervals of QTL for oil content. Finally, the function of one gene that coded storage protein was verified by using a collection of Arabidopsis lines that can conditionally express the full length cDNA from developing seeds of B. napus.


Assuntos
Brassica napus/química , Brassica napus/genética , Óleos de Plantas/análise , Proteínas de Plantas/metabolismo , Sementes/química , Arabidopsis , Brassica napus/metabolismo , Tamanho Celular , DNA Complementar/genética , Eletroforese em Gel Bidimensional , Ácidos Graxos/análise , Genômica/métodos , Glucosinolatos/análise , Microscopia Confocal , Microscopia Eletrônica de Transmissão , Proteômica/métodos , Locos de Características Quantitativas/genética , Especificidade da Espécie
10.
J Med Chem ; 66(24): 16783-16806, 2023 12 28.
Artigo em Inglês | MEDLINE | ID: mdl-38085679

RESUMO

The chromatin-associated protein WDR5 (WD repeat domain 5) is an essential cofactor for MYC and a conserved regulator of ribosome protein gene transcription. It is also a high-profile target for anti-cancer drug discovery, with proposed utility against both solid and hematological malignancies. We have previously discovered potent dihydroisoquinolinone-based WDR5 WIN-site inhibitors with demonstrated efficacy and safety in animal models. In this study, we sought to optimize the bicyclic core to discover a novel series of WDR5 WIN-site inhibitors with improved potency and physicochemical properties. We identified the 3,4-dihydrobenzo[f][1,4]oxazepin-5(2H)-one core as an alternative scaffold for potent WDR5 inhibitors. Additionally, we used X-ray structural analysis to design partially saturated bicyclic P7 units. These benzoxazepinone-based inhibitors exhibited increased cellular potency and selectivity and favorable physicochemical properties compared to our best-in-class dihydroisoquinolinone-based counterparts. This study opens avenues to discover more advanced WDR5 WIN-site inhibitors and supports their development as novel anti-cancer therapeutics.


Assuntos
Antineoplásicos , Repetições WD40 , Animais , Descoberta de Drogas , Antineoplásicos/farmacologia
11.
J Med Chem ; 65(8): 6287-6312, 2022 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-35436124

RESUMO

WD repeat domain 5 (WDR5) is a nuclear scaffolding protein that forms many biologically important multiprotein complexes. The WIN site of WDR5 represents a promising pharmacological target in a variety of human cancers. Here, we describe the optimization of our initial WDR5 WIN-site inhibitor using a structure-guided pharmacophore-based convergent strategy to improve its druglike properties and pharmacokinetic profile. The core of the previous lead remained constant while a focused SAR effort on the three pharmacophore units was combined to generate a new in vivo lead series. Importantly, this new series of compounds has picomolar binding affinity, improved cellular antiproliferative activity and selectivity, and increased kinetic aqueous solubility. They also exhibit a desirable oral pharmacokinetic profile with manageable intravenous clearance and high oral bioavailability. Thus, these new leads are useful probes toward studying the effects of WDR5 inhibition.


Assuntos
Peptídeos e Proteínas de Sinalização Intracelular , Humanos , Repetições WD40
12.
Nanoscale ; 13(5): 2811-2819, 2021 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-33508048

RESUMO

Nickel (Ni)-rich layered oxides such as LiNi0.6Co0.2Mn0.2O2 (NCM622) represent one of the most promising candidates for next-generation high-energy lithium-ion batteries (LIBs). However, the pristine Ni-rich cathode materials usually suffer from poor structural stability during cycling. In this work, we demonstrate a simple but effective approach to improve the cycling stability of the NCM622 cathode by dry coating of ultrastable Li3V2(PO4)3-carbon (LVP-C) nanoparticles, which leads to a robust composite cathode (NCM622/LVP-C) without sacrificing the specific energy density compared with pristine NCM622. The optimal NCM622/LVP-C composite presents a high specific capacity of 162 mA h g-1 at 0.5 C and excellent cycling performance with 85.0% capacity retention after 200 cycles at 2 C, higher than that of the pristine NCM622 (67.6%). Systematic characterization confirms that the LVP-C protective layer can effectively reduce the side reactions, restrict the cation mixing of NCM622 and improve its structural stability. Moreover, the NCM622/LVP-C||graphite full cells also show a commercial-level capacity of 3.2 mA h cm-2 and much improved cycling stability compared with NCM622/LVP-C||graphite full cells, indicating the great promise for low-cost, high-capacity and long-life LIBs.

13.
ACS Chem Biol ; 16(5): 787-793, 2021 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-33877812

RESUMO

Chemical synthesis has been described as a central science. Its practice provides access to the chemical structures of known and/or designed function. In particular, human health is greatly impacted by synthesis that enables advancements in both basic science discoveries in chemical biology as well as translational research that can lead to new therapeutics. To support the chemical synthesis needs of investigators across campus, the Vanderbilt Institute of Chemical Biology established a chemical synthesis core as part of its foundation in 2008. Provided in this Review are examples of synthetic products, known and designed, produced in the core over the past 10 years.


Assuntos
Técnicas de Química Sintética/métodos , Indicadores e Reagentes/síntese química , Preparações Farmacêuticas/síntese química , Animais , Produtos Biológicos/síntese química , Fenômenos Biofísicos , Meios de Contraste/síntese química , Humanos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Pesquisa , Estudos Retrospectivos , Estereoisomerismo
14.
J Am Chem Soc ; 132(32): 11058-70, 2010 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-20698672

RESUMO

NMR spectroscopy and molecular dynamics (MD) simulations were used to probe the structure and dynamics of complexes of three phosphotyrosine-derived peptides with the Src SH2 domain in an effort to uncover a structural explanation for enthalpy-entropy compensation observed in the binding thermodynamics. The series of phosphotyrosine peptide derivatives comprises the natural pYEEI Src SH2 ligand, a constrained mimic, in which the phosphotyrosine (pY) residue is preorganized in the bound conformation for the purpose of gaining an entropic advantage to binding, and a flexible analogue of the constrained mimic. The expected gain in binding entropy of the constrained mimic was realized; however, a balancing loss in binding enthalpy was also observed that could not be rationalized from the crystallographic structures. We examined protein dynamics to evaluate whether the observed enthalpic penalty might be the result of effects arising from altered motions in the complex. (15)N-relaxation studies and positional fluctuations from molecular dynamics indicate that the main-chain dynamics of the protein show little variation among the three complexes. Root mean squared (rms) coordinate deviations vary by less than 1.5 A for all non-hydrogen atoms for the crystal structures and in the ensemble average structures calculated from the simulations. In contrast to this striking similarity in the structures and dynamics, there are a number of large chemical shift differences from residues across the binding interface, but particularly from key Src SH2 residues that interact with pY, the "hot spot" residue, which contributes about one-half of the binding free energy. Rank-order correlations between chemical shifts and ligand binding enthalpy for several pY-binding residues, coupled with available mutagenesis and calorimetric data, suggest that subtle structural perturbations (<1 A) from the conformational constraint of the pY residue sufficiently alter the geometry of enthalpically critical interactions in the binding pocket to cause the loss of binding enthalpy, leading to the observed enthalpy-entropy compensation. We find no evidence to support the premise that enthalpy-entropy compensation is an inherent property and conclude that preorganization of Src SH2 ligand residues involved in binding hot spots may eventuate in suboptimal interactions with the domain. We propose that introducing constraints elsewhere in the ligand could minimize enthalpy-entropy compensation effects. The results illustrate the utility of the NMR chemical shift to highlight small, but energetically significant, perturbations in structure that might otherwise go unnoticed in an apparently rigid protein.


Assuntos
Entropia , Simulação de Dinâmica Molecular , Ressonância Magnética Nuclear Biomolecular , Domínios de Homologia de src , Ligantes , Proteína Oncogênica pp60(v-src)/química , Proteína Oncogênica pp60(v-src)/metabolismo , Ligação Proteica
15.
Eur J Med Chem ; 208: 112771, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32916312

RESUMO

Understanding how making structural changes in small molecules affects their binding affinities for targeted proteins is central to improving strategies for rational drug design. To assess the effects of varying the nature of nonpolar groups upon binding entropies and enthalpies, we designed and prepared a set of Grb2-SH2 domain ligands, Ac-pTyr-Ac6c-Asn-(CH2)n-R, in which the size and electrostatic nature of R groups at the pTyr+3 site were varied. The complexes of these ligands with the Grb2-SH2 domain were evaluated in a series of studies in which the binding thermodynamics were determined using isothermal titration calorimetry, and binding interactions were examined in crystallographic studies of two different complexes. Notably, adding nonpolar groups to the pTyr+3 site leads to higher binding affinities, but the magnitude and energetic origins of these effects vary with the nature of the R substituent. For example, enhancements to binding affinities using aliphatic R groups are driven by more favorable changes in binding entropies, whereas aryl R groups improve binding free energies through a combination of more favorable changes in binding enthalpies and entropies. However, enthalpy/entropy compensation plays a significant role in these associations and mitigates against any significant variation in binding free energies, which vary by only 0.8 kcal•mol-1, with changes in the electrostatic nature and size of the R group. Crystallographic studies show that differences in ΔG° or ΔH° correlate with buried nonpolar surface area, but they do not correlate with the total number of polar or van der Waals contacts. The relative number of ordered water molecules and relative order in the side chains at pTyr+3 correlate with differences in -TΔS°. Overall, these studies show that burial of nonpolar surface can lead to enhanced binding affinities arising from dominating entropy- or enthalpy-driven hydrophobic effects, depending upon the electrostatic nature of the apolar R group.


Assuntos
Proteína Adaptadora GRB2/metabolismo , Oligopeptídeos/metabolismo , Calorimetria , Cristalografia por Raios X , Proteína Adaptadora GRB2/química , Humanos , Interações Hidrofóbicas e Hidrofílicas , Ligantes , Oligopeptídeos/síntese química , Ligação Proteica , Termodinâmica , Domínios de Homologia de src
16.
Chem Commun (Camb) ; 56(92): 14412-14415, 2020 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-33146179

RESUMO

Here, a new strategy is reported for the preparation of a new class of nanocomposite anode materials consisting of ppm-level phosphorus-doped Si nanoparticles (P-Si) wrapped in a network of poly-γ-glutamate and graphene. The network produces not only a conductivity-enhanced conduit but also a mechanical stress buffer. The incorporation of poly-γ-glutamate in the nanocomposite enables self-healing capability and maintains the electrode structural integrity. This multifunctionality has significant implications for advancing the design of stable Si-based nanomaterials as high-performance anodes in Li-ion batteries.

17.
J Med Chem ; 63(2): 656-675, 2020 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-31858797

RESUMO

WD repeat domain 5 (WDR5) is a member of the WD40-repeat protein family that plays a critical role in multiple chromatin-centric processes. Overexpression of WDR5 correlates with a poor clinical outcome in many human cancers, and WDR5 itself has emerged as an attractive target for therapy. Most drug-discovery efforts center on the WIN site of WDR5 that is responsible for the recruitment of WDR5 to chromatin. Here, we describe discovery of a novel WDR5 WIN site antagonists containing a dihydroisoquinolinone bicyclic core using a structure-based design. These compounds exhibit picomolar binding affinity and selective concentration-dependent antiproliferative activities in sensitive MLL-fusion cell lines. Furthermore, these WDR5 WIN site binders inhibit proliferation in MYC-driven cancer cells and reduce MYC recruitment to chromatin at MYC/WDR5 co-bound genes. Thus, these molecules are useful probes to study the implication of WDR5 inhibition in cancers and serve as a potential starting point toward the discovery of anti-WDR5 therapeutics.


Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Compostos Bicíclicos Heterocíclicos com Pontes/síntese química , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Quinolonas/síntese química , Quinolonas/farmacologia , Repetições WD40/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células , Cromatina/efeitos dos fármacos , Cromatina/genética , Cristalografia por Raios X , Desenho de Fármacos , Descoberta de Drogas , Repressão Epigenética/efeitos dos fármacos , Genes myc/efeitos dos fármacos , Humanos , Relação Estrutura-Atividade
18.
Nanoscale ; 11(2): 520-531, 2019 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-30543226

RESUMO

Two-dimensional nanosheet-like materials with ultra-small thickness and uniform porous structures hold great promise for high-rate and long-life lithium-ion batteries. In this work, pure ultrathin mesoporous Li4Ti5O12 nanosheets are fabricated by combining a facile solvothermal synthesis with a calcination process. The detailed formation mechanism of ultrathin mesoporous Li4Ti5O12 nanosheets is systematically investigated, which identified the key factors that control the structure development. The unique structural features including ultra-small thickness, large specific surface area and uniform mesoporous structures endow such materials with effective charge transport channels, abundant reaction active sites and inner-plain void space for improved structural stability. As a result, the ultrathin mesoporous Li4Ti5O12 nanosheets offer nearly theoretical capacity (174 mA h g-1 at 1 C), very high rate capability (e.g., 145 mA h g-1 at 50 C), and excellent cycling stability (95% capacity retention after 2500 cycles at 20 C), suggesting their great promise as anode materials for ultrahigh-power and long-life lithium-ion batteries.

19.
ACS Appl Mater Interfaces ; 11(50): 46767-46775, 2019 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-31763822

RESUMO

In response to the concept of "compact energy storage", research on electrolyte dosage dwindling is definitely efficient owing to present electrolyte usage up to 70 wt % in a cell. While less electrolyte usage leads to slow reaction kinetics. Herein, a heterojunction, MoP/MoS2 core with much defects and vacancies coated by porous carbon shell, is synthesized. Besides, the small particle size of MoP/MoS2@C facilitates a close packing to form a dense and porous modified layer on PP-based (F-PP) separator. The heterojunction with defects exposes abundant interfaces and assures an adequate local electrolyte availability and an improved electrolyte affinity that are beneficial for Li+ transfer. When using F-PP separator, Li-S cell performs well in the lean electrolyte. Apart from a high discharging capacity of 517.1 mAh g-1 at 5 C in E/S = 10 (only half benchmark dosage), the cell realizes a favorable stability at C/2 over 500 cycles even in E/S = 7 (0.065% decay per cycle), demonstrating an effective polysulfides (PS) shuttling relief and reversibility of PS-relating chemical conversion. All these enhanced electrochemical behaviors in lean electrolyte result from a three-in-one strategy realized by defects-included MoP/MoS2@C heterojunction, including incorporating the lithiuphilic and sulfophilic sites for PS confinement and electrocatalysis triggered by abundant S vacancies and Lewis and Brønsted acid sites.

20.
Chem Commun (Camb) ; (8): 975-7, 2008 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-18283354

RESUMO

Polyisobutylene is shown to be a nonpolar phase tag that separates a highly colored salen Cr(III) complex from products but is otherwise kinetically similar to a low molecular weight salen Cr(III) complex in polycarbonate formation by Cr(III)-catalyzed copolymerization of CO2 and cyclohexene oxide.


Assuntos
Cromo/química , Etilenodiaminas/química , Compostos Organometálicos/química , Cimento de Policarboxilato/síntese química , Polienos/síntese química , Polímeros/síntese química , Dióxido de Carbono/química , Catálise , Cicloexenos/química , Ésteres/síntese química , Ésteres/química , Cinética , Estrutura Molecular , Peso Molecular , Compostos Organometálicos/síntese química , Cimento de Policarboxilato/química , Polienos/química , Polímeros/química , Fatores de Tempo
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