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Owing to the wide and growing demand for primary alcohols, the development of efficient catalysts with high regioselectivity remains a worthwhile pursuit. However, according to Markovnikov's rule, it is a challenge to obtain primary alcohols with high yields and regioselectivity from terminal alkenes or alkynes. Herein, we report the synthesis of a photosensitizing two-dimensional (2D) metal-organic framework (MOF) from cyclic trinuclear copper(I) units (Cu-CTUs) and a boron dipyrro-methene (Bodipy) ligand. The MOF features broadband light absorption, excellent photoinduced charge separation efficiency, and photochemical properties. By integrating the copper-catalyzed hydroboration and photocatalyzed aerobic oxidation, it can catalyze terminal alkenes and alkynes to produce primary alcohols via a one-pot tandem reaction with excellent regioselectivity, good overall yields in two-step reactions (up to 85 %), broad substrate compatibility (32â examples) and good reusability under mild conditions.
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The synthesis of atomically precise copper nanoclusters (Cu-NCs) with high chemical stability is a prerequisite for practical applications, yet still remains a long-standing challenge. Herein, we have prepared a pyrazolate-protected Cu-NC (Cu8), which exhibited exceptional chemical stability either in solid-state or in solution. The crystals of Cu8 are still suitable for single crystal X-ray diffraction analysis even after being treated with boiling water, 8â wt % H2 O2 , high concentrated acid (1â M HCl) or saturated base (≈20â M KOH), respectively. More importantly, the structure of Cu8 in solution also remained intact toward oxygen, organic acid (100â eq. HOAc) or base (400â eq. dibutylamine) confirmed by 1 Hâ NMR and UV/Vis analysis. Taking advantage of high alkali-resistant, Cu8 illustrates excellent catalytic activity for the synthesis of indolizines, and it can be reused for at least 10 cycles without losing catalytic performance.
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BACKGROUND We aimed to explore the risk factors that affect the serum concentration of sodium valproate (VPA-Na) in patients with epilepsy and to provide references for the rationale of the use of VPA-Na. MATERIAL AND METHODS The enzyme-multiplied immunoassay technique was used to determine the serum VPA-NA concentrations of 109 patients, and the results were retrospectively analyzed and summarized. A multivariate logistic regression model was used to analyze substandard serum VPA-Na concentrations. RESULTS Fifty-six patients (51.38%) treated with VPA-Na tablets were within the effective treatment range of 50-100 µg/mL, while 53 patients (48.62%) were out of the treatment range. The results indicated that the standard-reaching rate of serum drug concentration in the juvenile group was higher than that in the adult and elderly groups; the standard-reaching rates of serum drug concentrations in the low-dose group and the intermediate-dose group were lower than that in the high-dose group; and the standard-reaching rate of serum drug concentration in the group receiving carbapenems in combination was lower than that in the non-combination group; all differences were statistically significant. The combination with carbapenems and enzyme inducers was an independent risk factor for VPA-Na serum concentration below the target level in hospitalized patients. CONCLUSIONS To improve clinical efficacy and reduce the occurrence of adverse reactions, there is a need for therapeutic drug monitoring of VPA-Na. Moreover, individual administration should be implemented when VPA-Na tablets are used in the treatment of epilepsy because of the significant fluctuation in VPA-Na blood concentration.
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Anticonvulsivantes/sangue , Anticonvulsivantes/uso terapêutico , Epilepsia/sangue , Epilepsia/tratamento farmacológico , Ácido Valproico/sangue , Ácido Valproico/uso terapêutico , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Relação Dose-Resposta a Droga , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do Tratamento , Adulto JovemRESUMO
Expressional changes of pain-associated genes in primary sensory neurons of DRG are critical for neuropathic pain genesis. DNA methyltransferase (DNMT)-triggered DNA methylation silences gene expression. We show here that DNMT1, a canonical maintenance methyltransferase, acts as the de novo DNMT and is required for neuropathic pain genesis likely through repressing at least DRG Kcna2 gene expression in male mice. Peripheral nerve injury upregulated DNMT1 expression in the injured DRG through the transcription factor cAMP response element binding protein-triggered transcriptional activation of Dnmt1 gene. Blocking this upregulation prevented nerve injury-induced DNA methylation within the promoter and 5'-untranslated region of Kcna2 gene, rescued Kcna2 expression and total Kv current, attenuated hyperexcitability in the injured DRG neurons, and alleviated nerve injury-induced pain hypersensitivities. Given that Kcna2 is a key player in neuropathic pain, our findings suggest that DRG DNMT1 may be a potential target for neuropathic pain management.SIGNIFICANCE STATEMENT In the present study, we reported that DNMT1, a canonical DNA maintenance methyltransferase, is upregulated via the activation of the transcription factor CREB in the injured DRG after peripheral nerve injury. This upregulation was responsible for nerve injury-induced de novo DNA methylation within the promoter and 5'-untranslated region of the Kcna2 gene, reductions in Kcna2 expression and Kv current and increases in neuronal excitability in the injured DRG. Since pharmacological inhibition or genetic knockdown of DRG DNMT1 alleviated nerve injury-induced pain hypersensitivities, DRG DNMT1 contributes to neuropathic pain genesis partially through repression of DRG Kcna2 gene expression.
Assuntos
DNA (Citosina-5-)-Metiltransferase 1/metabolismo , Repressão Epigenética/fisiologia , Canal de Potássio Kv1.2/metabolismo , Neuralgia/metabolismo , Neurônios Aferentes/metabolismo , Animais , Gânglios Espinais/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Traumatismos dos Nervos Periféricos/metabolismoRESUMO
Metal-organic framework (MOF) glasses are promising candidates for membrane fabrication due to their significant porosity, the ease of processing, and most notably, the potential to eliminate the grain boundary that is unavoidable for polycrystalline MOF membranes. Herein, we developed a ZIF-62 MOF glass membrane and exploited its intrinsic gas-separation properties. The MOF glass membrane was fabricated by melt-quenching treatment of an in situ solvothermally synthesized polycrystalline ZIF-62 MOF membrane on a porous ceramic alumina support. The molten ZIF-62 phase penetrated into the nanopores of the support and eliminated the formation of intercrystalline defects in the resultant glass membrane. The molecular sieving ability of the MOF membrane is remarkably enhanced via vitrification. The separation factors of the MOF glass membrane for H2 /CH4 , CO2 /N2 and CO2 /CH4 mixtures are 50.7, 34.5, and 36.6, respectively, far exceeding the Robeson upper bounds.
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ZIF-8 membranes have emerged as the most promising candidate for propylene/propane (C3 H6 /C3 H8 ) separation through its precise molecular sieving characteristics. The poor reproducibility and durability, and high cost, thus far hinder the scalable synthesis and industrial application of ZIF-8 membranes. Herein, we report a semi-solid process featuring ultrafast and high-yield synthesis, and outstanding scalability for reproducible fabrication of ZIF-8 membranes. The membranes show excellent C3 H6 /C3 H8 separation performance in a wide temperature and pressure range, and remarkable stability over 6â months. The ZIF-8 membrane features dimethylacetamide entrapped ZIF-8 crystals retaining the same diffusion characteristics but offering enhanced adsorptive selectivity for C3 H6 /C3 H8 . The ZIF-8 membrane was prepared on a commercial flat-sheet ceramic substrate. A prototypical plate-and-frame membrane module with an effective membrane area of about 300â cm2 was used for efficient C3 H6 /C3 H8 separation.
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The transmission of normal sensory and/or acute noxious information requires intact expression of pain-associated genes within the pain pathways of nervous system. Expressional changes of these genes after peripheral nerve injury are also critical for neuropathic pain induction and maintenance. Methyl-CpG-binding domain protein 1 (MBD1), an epigenetic repressor, regulates gene transcriptional activity. We report here that MBD1 in the primary sensory neurons of DRG is critical for the genesis of acute pain and neuropathic pain as DRG MBD1-deficient mice exhibit the reduced responses to acute mechanical, heat, cold, and capsaicin stimuli and the blunted nerve injury-induced pain hypersensitivities. Furthermore, DRG overexpression of MBD1 leads to spontaneous pain and evoked pain hypersensitivities in the WT mice and restores acute pain sensitivities in the MBD1-deficient mice. Mechanistically, MDB1 represses Oprm1 and Kcna2 gene expression by recruiting DNA methyltransferase DNMT3a into these two gene promoters in the DRG neurons. DRG MBD1 is likely a key player under the conditions of acute pain and neuropathic pain.SIGNIFICANCE STATEMENT In the present study, we revealed that the mice with deficiency of methyl-CpG-binding domain protein 1 (MBD1), an epigenetic repressor, in the DRG displayed the reduced responses to acute noxious stimuli and the blunted neuropathic pain. We also showed that DRG overexpression of MBD1 produced the hypersensitivities to noxious stimuli in the WT mice and rescued acute pain sensitivities in the MBD1-deficient mice. We have also provided the evidence that MDB1 represses Oprm1 and Kcna2 gene expression by recruiting DNA methyltransferase DNMT3a into these two gene promoters in the DRG neurons. DRG MBD1 may participate in the genesis of acute pain and neuropathic pain likely through regulating DNMT3a-controlled Oprm1 and Kcna2 gene expression in the DRG neurons.
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Dor Aguda/metabolismo , Proteínas de Ligação a DNA/biossíntese , Epigênese Genética/fisiologia , Canal de Potássio Kv1.2/biossíntese , Neuralgia/metabolismo , Receptores Opioides mu/biossíntese , Dor Aguda/genética , Animais , Células Cultivadas , Proteínas de Ligação a DNA/genética , Gânglios Espinais/química , Gânglios Espinais/metabolismo , Inativação Gênica/fisiologia , Canal de Potássio Kv1.2/antagonistas & inibidores , Canal de Potássio Kv1.2/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neuralgia/genética , Receptores Opioides mu/antagonistas & inibidores , Receptores Opioides mu/genética , Células Receptoras Sensoriais/química , Células Receptoras Sensoriais/metabolismoRESUMO
Antineoplastic drugs induce dramatic transcriptional changes in dorsal root ganglion (DRG) neurons, which may contribute to chemotherapy-induced neuropathic pain. K2p 1.1 controls neuronal excitability by setting the resting membrane potential. Here, we report that systemic injection of the chemotherapy agent paclitaxel time-dependently downregulates the expression of K 2p 1.1 mRNA and its coding K2p 1.1 protein in the DRG neurons. Rescuing this downregulation mitigates the development and maintenance of paclitaxel-induced mechanical allodynia and heat hyperalgesia. Conversely, in the absence of paclitaxel administration, mimicking this downregulation decreases outward potassium current and increases excitability in the DRG neurons, leading to the enhanced responses to mechanical and heat stimuli. Mechanically, the downregulation of DRG K 2p 1.1 mRNA is attributed to paclitaxel-induced increase in DRG DNMT3a, as blocking this increase reverses the paclitaxel-induced the decrease of DRG K2p 1.1 and mimicking this increase reduces DRG K2p 1.1 expression. In addition, paclitaxel injection increases the binding of DNMT3a to the K 2p 1.1 gene promoter region and elevates the level of DNA methylation within this region in the DRG. These findings suggest that DNMT3a-triggered downregulation of DRG K2p 1.1 may contribute to chemotherapy-induced neuropathic pain.
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DNA (Citosina-5-)-Metiltransferases/metabolismo , Regulação para Baixo , Paclitaxel/administração & dosagem , Canais de Potássio de Domínios Poros em Tandem/metabolismo , Células Receptoras Sensoriais/efeitos dos fármacos , Animais , Células Cultivadas , DNA (Citosina-5-)-Metiltransferases/genética , Metilação de DNA/efeitos dos fármacos , DNA Metiltransferase 3A , Gânglios Espinais/citologia , Gânglios Espinais/efeitos dos fármacos , Gânglios Espinais/metabolismo , Humanos , Hiperalgesia/induzido quimicamente , Hiperalgesia/fisiopatologia , Masculino , Camundongos Knockout , Neuralgia/induzido quimicamente , Neuralgia/fisiopatologia , Técnicas de Patch-Clamp , Canais de Potássio de Domínios Poros em Tandem/genética , Interferência de RNA , Células Receptoras Sensoriais/metabolismo , Células Receptoras Sensoriais/fisiologiaRESUMO
To develop new antibacterial agents, a series of novel triazole-containing pyrazole ester derivatives were designed and synthesized and their biological activities were evaluated as potential topoisomerase II inhibitors. Compound 4d exhibited the most potent antibacterial activity with Minimum inhibitory concentration (MIC) alues of 4 µg/mL, 2 µg/mL, 4 µg/mL, and 0.5 µg/mL against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Salmonella gallinarum, respectively. The in vivo enzyme inhibition assay 4d displayed the most potent topoisomerase II (IC50 = 13.5 µg/mL) and topoisomerase IV (IC50 = 24.2 µg/mL) inhibitory activity. Molecular docking was performed to position compound 4d into the topoisomerase II active site to determine the probable binding conformation. In summary, compound 4d may serve as potential topoisomerase II inhibitor.
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Antibacterianos/química , Pirazóis/química , Triazóis/química , Antibacterianos/farmacologia , DNA Girase/química , Ésteres , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Estrutura Molecular , Pirazóis/farmacologia , Relação Estrutura-Atividade , Inibidores da Topoisomerase II/química , Inibidores da Topoisomerase II/farmacologiaRESUMO
Rosmarinic acid (RA) is a natural polyphenolic compound that exists in many medicinal species of Boraginaceae and Lamiaceae. The previous studies have revealed that RA had therapeutic effects on hepatocellular carcinoma (HCC) in the H22-xenograft models by inhibiting the inflammatory cytokines and NF-κB p65 pathway in the tumor microenvironment. However, its molecular mechanisms of immunoregulation and pro-apoptotic effect in HCC have not been fully explored. In the present study, RA at 75, 150, and 300 mg/kg was given to H22 tumor-bearing mice via gavage once a day for 10 days. The results showed that RA can effectively inhibit the tumor growth through regulating the ratio of CD4+/CD8+ and the secretion of interleukin (IL)-2 and interferon-γ, inhibiting the expressions of IL-6, IL-10 and signal transducer and activator of transcription 3, thereby up-regulating Bax and Caspase-3 and down-regulating Bcl-2. The underlying mechanisms involved regulation of immune response and induction of HCC cell apoptosis. These results may provide a more comprehensive perspective to clarify the anti-tumor mechanism of RA in HCC.
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Apoptosis, as an innate antiviral defense, not only functions to limit viral replication by eliminating infected cells, but also contribute to viral dissemination, particularly at the late stages of infection. A highly neurotropic CVS strain of rabies virus induces apoptosis both in vitro and in vivo. However, the detailed mechanism of CVS-mediated neuronal apoptosis is not entirely clear. Here, we show that CVS induces apoptosis through mitochondrial pathway by dissipating mitochondrial membrane potential, release of cytochrome c and AIF. CVS blocks Bax activation at the early stages of infection; while M protein partially targets mitochondria and induces mitochondrial apoptosis at the late stages of infection. The α-helix structure spanning 67-79 amino acids of M protein is essential for mitochondrial targeting and induction of apoptosis. These results suggest that CVS functions on mitochondria to regulate apoptosis at different stages of infection, so as to for viral replication and dissemination.
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Apoptose , Mitocôndrias/metabolismo , Vírus da Raiva/metabolismo , Proteínas da Matriz Viral/metabolismo , Animais , Fator de Indução de Apoptose/metabolismo , Caspase 9/metabolismo , Linhagem Celular , Ativação Enzimática , Humanos , Potencial da Membrana Mitocondrial , Camundongos , Raiva/metabolismo , Raiva/virologia , Transdução de Sinais , Proteína X Associada a bcl-2/metabolismoRESUMO
Neuropathic pain, a distressing and debilitating disorder, is still poorly managed in clinic. Opioids, like morphine, remain the mainstay of prescribed medications in the treatment of this disorder, but their analgesic effects are highly unsatisfactory in part due to nerve injury-induced reduction of opioid receptors in the first-order sensory neurons of dorsal root ganglia. G9a is a repressor of gene expression. We found that nerve injury-induced increases in G9a and its catalyzed repressive marker H3K9m2 are responsible for epigenetic silencing of Oprm1, Oprk1, and Oprd1 genes in the injured dorsal root ganglia. Blocking these increases rescued dorsal root ganglia Oprm1, Oprk1, and Oprd1 gene expression and morphine or loperamide analgesia and prevented the development of morphine or loperamide-induced analgesic tolerance under neuropathic pain conditions. Conversely, mimicking these increases reduced the expression of three opioid receptors and promoted the mu opioid receptor-gated release of primary afferent neurotransmitters. Mechanistically, nerve injury-induced increases in the binding activity of G9a and H3K9me2 to the Oprm1 gene were associated with the reduced binding of cyclic AMP response element binding protein to the Oprm1 gene. These findings suggest that G9a participates in the nerve injury-induced reduction of the Oprm1 gene likely through G9a-triggered blockage in the access of cyclic AMP response element binding protein to this gene.
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Proteína de Ligação a CREB/metabolismo , Gânglios Espinais/patologia , Histona-Lisina N-Metiltransferase/metabolismo , Traumatismos dos Nervos Periféricos/patologia , Receptores Opioides mu/metabolismo , Células Receptoras Sensoriais/metabolismo , Animais , Proteína de Ligação a CREB/genética , Modelos Animais de Doenças , Ala(2)-MePhe(4)-Gly(5)-Encefalina/farmacologia , Lateralidade Funcional , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/genética , Histona-Lisina N-Metiltransferase/genética , Loperamida/farmacologia , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Proteínas dos Microfilamentos/genética , Proteínas dos Microfilamentos/metabolismo , Entorpecentes/farmacologia , Entorpecentes/uso terapêutico , Ratos Sprague-Dawley , Receptores Opioides/genética , Receptores Opioides/metabolismo , Receptores Opioides delta/genética , Receptores Opioides delta/metabolismo , Células Receptoras Sensoriais/efeitos dos fármacos , Receptor de NociceptinaRESUMO
BACKGROUND: Peripheral nerve injury leads to changes in gene expression in primary sensory neurons of the injured dorsal root ganglia. These changes are believed to be involved in neuropathic pain genesis. Previously, these changes have been identified using gene microarrays or next generation RNA sequencing with poly-A tail selection, but these approaches cannot provide a more thorough analysis of gene expression alterations after nerve injury. METHODS: The present study chose to eliminate mRNA poly-A tail selection and perform strand-specific next generation RNA sequencing to analyze whole transcriptomes in the injured dorsal root ganglia following spinal nerve ligation. Quantitative real-time reverse transcriptase polymerase chain reaction assay was carried out to verify the changes of some differentially expressed RNAs in the injured dorsal root ganglia after spinal nerve ligation. RESULTS: Our results showed that more than 50 million (M) paired mapped sequences with strand information were yielded in each group (51.87 M-56.12 M in sham vs. 51.08 M-57.99 M in spinal nerve ligation). Six days after spinal nerve ligation, expression levels of 11,163 out of a total of 27,463 identified genes in the injured dorsal root ganglia significantly changed, of which 52.14% were upregulated and 47.86% downregulated. The largest transcriptional changes were observed in protein-coding genes (91.5%) followed by noncoding RNAs. Within 944 differentially expressed noncoding RNAs, the most significant changes were seen in long interspersed noncoding RNAs followed by antisense RNAs, processed transcripts, and pseudogenes. We observed a notable proportion of reads aligning to intronic regions in both groups (44.0% in sham vs. 49.6% in spinal nerve ligation). Using quantitative real-time polymerase chain reaction, we confirmed consistent differential expression of selected genes including Kcna2, Oprm1 as well as lncRNAs Gm21781 and 4732491K20Rik following spinal nerve ligation. CONCLUSION: Our findings suggest that next generation RNA sequencing can be used as a promising approach to analyze the changes of whole transcriptomes in dorsal root ganglia following nerve injury and to possibly identify new targets for prevention and treatment of neuropathic pain.
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Gânglios Espinais/metabolismo , Perfilação da Expressão Gênica/métodos , Traumatismos dos Nervos Periféricos/genética , Processamento Alternativo/genética , Animais , Gânglios Espinais/patologia , Genoma , Hiperalgesia/complicações , Hiperalgesia/genética , Ligadura , Vértebras Lombares/patologia , Masculino , Camundongos Endogâmicos C57BL , Traumatismos dos Nervos Periféricos/complicações , Reação em Cadeia da Polimerase em Tempo Real , Reprodutibilidade dos Testes , Análise de Sequência de RNA , Transdução de Sinais/genética , Nervos Espinhais/patologiaRESUMO
Cytoplasmic actin and actin-associated proteins have been identified in RABV particles. Although actin is involved in RABV entry into cells, the specific role of actin in RABV budding and release remains unknown. Our study found that RABV M protein-mediated virion budding depends on intact actin filaments. Confocal microscopy demonstrated a block to virions budding, with a number of M protein-mediated budding vesicles detained in the cell cytoplasm. Furthermore, RABV infection resulted in inactivation of cofilin and upregulation of phosphorylated cofilin. Knockdown of cofilin reduced RABV release. These results for the first time indicate that RABV infection resulted in upregulation of phosphorylated cofilin to facililtate actin polymerization for virus budding.
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Fatores de Despolimerização de Actina/metabolismo , Neurônios/virologia , Vírus da Raiva/fisiologia , Proteínas da Matriz Viral/metabolismo , Proteínas Virais/metabolismo , Liberação de Vírus/fisiologia , Animais , Linhagem Celular , Regulação para Baixo/fisiologia , CamundongosRESUMO
BACKGROUND: Peripheral nerve injury-induced gene alterations in the dorsal root ganglion (DRG) and spinal cord likely participate in neuropathic pain genesis. Histone methylation gates gene expression. Whether the suppressor of variegation 3-9 homolog 1 (SUV39H1), a histone methyltransferase, contributes to nerve injury-induced nociceptive hypersensitivity is unknown. METHODS: Quantitative real-time reverse transcription polymerase chain reaction analysis, Western blot analysis, or immunohistochemistry were carried out to examine the expression of SUV39H1 mRNA and protein in rat DRG and dorsal horn and its colocalization with DRG µ-opioid receptor (MOR). The effects of a SUV39H1 inhibitor (chaetocin) or SUV39H1 siRNA on fifth lumbar spinal nerve ligation (SNL)-induced DRG MOR down-regulation and nociceptive hypersensitivity were examined. RESULTS: SUV39H1 was detected in neuronal nuclei of the DRG and dorsal horn. It was distributed predominantly in small DRG neurons, in which it coexpressed with MOR. The level of SUV39H1 protein in both injured DRG and ipsilateral fifth lumbar dorsal horn was time dependently increased after SNL. SNL also produced an increase in the amount of SUV39H1 mRNA in the injured DRG (n = 6/time point). Intrathecal chaetocin or SUV39H1 siRNA as well as DRG or intraspinal microinjection of SUV39H1 siRNA impaired SNL-induced allodynia and hyperalgesia (n = 5/group/treatment). DRG microinjection of SUV39H1 siRNA also restored SNL-induced DRG MOR down-regulation (n = 6/group). CONCLUSIONS: The findings of this study suggest that SUV39H1 contributes to nerve injury-induced allodynia and hyperalgesia through gating MOR expression in the injured DRG. SUV39H1 may be a potential target for the therapeutic treatment of nerve injury-induced nociceptive hypersensitivity.
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Gânglios Espinais/metabolismo , Hiperalgesia/metabolismo , Metiltransferases/metabolismo , Neuralgia/metabolismo , Traumatismos dos Nervos Periféricos/metabolismo , Proteínas Repressoras/metabolismo , Corno Dorsal da Medula Espinal/metabolismo , Animais , Western Blotting , Modelos Animais de Doenças , Regulação para Baixo/genética , Hiperalgesia/genética , Imuno-Histoquímica , Masculino , Metiltransferases/genética , Neuralgia/genética , Traumatismos dos Nervos Periféricos/genética , Ratos , Ratos Sprague-Dawley , Proteínas Repressoras/genética , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Mitogen activated protein kinase (MAPK) signal transduction pathway has been proved to play an important role in tumorigenesis and cancer development. MEK inhibitor has been demonstrated significant clinical benefit for blocking MAPK pathway activation and possibly could block reactivation of the MAPK pathway at the time of BRAF inhibitor resistance. Twenty N-(benzyloxy)-1,3-diphenyl-1H-pyrazole-4-carboxamide derivatives have been designed and synthesized as MEK inhibitors, and their biological activities were evaluated. Among these compounds, compound 7b showed the most potent inhibitory activity with IC50 of 91nM for MEK1 and GI50 value of 0.26µM for A549 cells. The SAR analysis and docking simulation were performed to provide crucial pharmacophore clues that could be used in further structure optimization.
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Antineoplásicos/química , Antineoplásicos/farmacologia , MAP Quinase Quinase 1/antagonistas & inibidores , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Pirazóis/química , Pirazóis/farmacologia , Compostos de Bifenilo/química , Compostos de Bifenilo/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Simulação de Acoplamento Molecular , Neoplasias/tratamento farmacológico , Neoplasias/enzimologia , Relação Quantitativa Estrutura-AtividadeRESUMO
Siderophores are iron (Fe)-binding secondary metabolites that have been investigated for their uranium-binding properties. Previous work has focused on characterizing hydroxamate types of siderophores, such as desferrioxamine B, for their uranyl (UO2)-binding affinity. Carboxylate forms of these metabolites hold potential to be more efficient chelators of UO2, yet they have not been widely studied. Desmalonichrome is a carboxylate siderophore that is not commercially available and so was obtained from the fungus Fusarium oxysporum cultivated under Fe-depleted conditions. The relative affinity for UO2 binding of desmalonichrome was investigated using a competitive analysis of binding affinities between UO2 acetate and different concentrations of Fe(III) chloride using electrospray ionization mass spectrometry. In addition to desmalonichrome, three other siderophores, including two hydroxamates (desferrioxamine B and desferrichrome) and one carboxylate (desferrichrome A), were studied to understand their relative affinities for the UO2(2+) ion at two pH values. The binding affinities of hydroxamate siderophores to UO2(2+) ions were observed to decrease with increasing Fe(III)Cl3 concentration at the lower pH. On the other hand, decreasing the pH has a smaller impact on the binding affinities between carboxylate siderophores and the UO2(2+) ion. Desmalonichrome in particular was shown to have the greatest relative affinity for UO2 at all pH and Fe(III) concentrations examined. These results suggest that acidic functional groups in the ligands are important for strong chelation with UO2 at lower pH.
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Fusarium/química , Sideróforos/química , Compostos de Urânio/química , Análise de Variância , Desferroxamina , Compostos Férricos/química , Estrutura MolecularRESUMO
Sequence control in polymers, well-known in nature, encodes structure and functionality. Here we introduce a new architecture, based on the nucleophilic aromatic substitution chemistry of cyanuric chloride, that creates a new class of sequence-defined polymers dubbed TZPs. Proof of concept is demonstrated with two synthesized hexamers, having neutral and ionizable side chains. Molecular dynamics simulations show backbone-backbone interactions, including H-bonding motifs and pi-pi interactions. This architecture is arguably biomimetic while differing from sequence-defined polymers having peptide bonds. The synthetic methodology supports the structural diversity of side chains known in peptides, as well as backbone-backbone hydrogen-bonding motifs, and will thus enable new macromolecules and materials with useful functions.
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Polímeros/química , Triazinas/química , Ligação de Hidrogênio , Simulação de Dinâmica Molecular , Espectrometria de Massas em TandemRESUMO
Methods to covalently conjugate Alexa Fluor dyes to cellulose nanocrystals, at limiting amounts that retain the overall structure of the nanocrystals as model cellulose materials, were developed using two approaches. In the first, aldehyde groups are created on the cellulose surfaces by reaction with limiting amounts of sodium periodate, a reaction well-known for oxidizing vicinal diols to create dialdehyde structures. Reductive amination reactions were then applied to bind Alexa Fluor dyes with terminal amino-groups on the linker section. In the absence of the reductive step, dye washes out of the nanocrystal suspension, whereas with the reductive step, a colored product is obtained with the characteristic spectral bands of the conjugated dye. In the second approach, Alexa Fluor dyes were modified to contain chloro-substituted triazine ring at the end of the linker section. These modified dyes then were reacted with cellulose nanocrystals in acetonitrile at elevated temperature, again isolating material with the characteristic spectral bands of the Alexa Fluor dye. Reactions with Alexa Fluor 546 are given as detailed examples, labeling on the order of 1% of the total glucopyranose rings of the cellulose nanocrystals at dye loadings of ca. 5 µg/mg cellulose. Fluorescent cellulose nanocrystals were deposited in pore network microfluidic structures (PDMS) and proof-of-principle bioimaging experiments showed that the spatial localization of the solid cellulose deposits could be determined, and their disappearance under the action of Celluclast enzymes or microbes could be observed over time. In addition, single molecule fluorescence microscopy was demonstrated as a method to follow the disappearance of solid cellulose deposits over time, following the decrease in the number of single blinking dye molecules with time instead of fluorescent intensity.
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Microambiente Celular , Celulose/análise , Corantes Fluorescentes/química , Nanopartículas/química , Compostos de Quinolínio/química , Celulose/química , Microscopia de Fluorescência/métodosRESUMO
The properties of two-dimensional covalent organic frameworks (2D COFs), including porosity, catalytic activity as well as electronic and optical properties, are greatly affected by their interlayer stacking structures. However, the precise control of their interlayer stacking mode, especially in a reversible fashion, is a long-standing and challenging pursuit. Herein, we prepare three 2D copper-organic frameworks, namely JNM-n (n = 7, 8, and 9). Interestingly, the reversible interlayer sliding between eclipsed AA stacking (i.e., JNM-7-AA and JNM-8-AA) and staggered ABC stacking (i.e., JNM-7-ABC and JNM-8-ABC) can be achieved through environmental stimulation, which endows reversible encapsulation and release of lipase. Importantly, JNM-7-AA and JNM-8-AA exhibit a broader light absorption range, higher charge-separation efficiency, and higher photocatalytic activity for sensitizing O2 to 1O2 and O2â¢- than their ABC stacking isostructures. Consequently, JNM-8-AA deliver significantly enhanced photocatalytic activities for oxidative cross-coupling reactions compared to JNM-8-ABC and other reported homogeneous and heterogeneous catalysts.