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1.
Environ Toxicol ; 2024 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-39162363

RESUMO

BACKGROUND: Necroptosis is a type of programmed cell death involved in the pathogenesis of cancers. This work developed a prognostic glioblastoma (GBM) model based on necroptosis-related genes. METHODS: RNA-Seq data were collected from the TCGA database. The "WGCNA" method was used to identify co-expression modules, based on which GO and KEGG analyses were conducted. A protein-protein interaction (PPI) network was compiled. The number of key prognostic genes was reduced applying COX regression and least absolute shrinkage and selection operator (LASSO) analysis to build a RiskScore model. Differences in immune microenvironments were assessed using CIBERSORT, ESTIMATE, MCP-count, and TIMER databases. The potential impact of key prognostic genes on GBM was validated by cellular experiments. RESULTS: GBM patients in the higher necroptosis score group had higher immune scores and worse survival. The Brown module, which was closely related to the necroptosis score, was considered as a key gene module. Three key genes (GZMB, PLAUR, SOCS3) were obtained by performing regression analysis on the five clusters. The RiskScore model was significantly, positively, correlated with necroptosis score. Low-risk patients could benefit from immunotherapy, while high-risk patients may be more suitable to take multiple chemotherapy drugs. The nomogram showed strong performance in survival prediction. GZMB, PLAUR, and SOCS3 played key roles in GBM development. Among them, high-expressed GZMB was related to the invasive and migratory abilities of GBM cells. CONCLUSIONS: A genetic signature associated with necroptosis was developed, and we constructed a RiskScore model to provide reference for predicting clinical outcomes and immunotherapy responses of patients with GBM.

2.
Sensors (Basel) ; 24(3)2024 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-38339474

RESUMO

Human activity recognition (HAR) based on wearable sensors has emerged as a low-cost key-enabling technology for applications such as human-computer interaction and healthcare. In wearable sensor-based HAR, deep learning is desired for extracting human active features. Due to the spatiotemporal dynamic of human activity, a special deep learning network for recognizing the temporal continuous activities of humans is required to improve the recognition accuracy for supporting advanced HAR applications. To this end, a residual multifeature fusion shrinkage network (RMFSN) is proposed. The RMFSN is an improved residual network which consists of a multi-branch framework, a channel attention shrinkage block (CASB), and a classifier network. The special multi-branch framework utilizes a 1D-CNN, a lightweight temporal attention mechanism, and a multi-scale feature extraction method to capture diverse activity features via multiple branches. The CASB is proposed to automatically select key features from the diverse features for each activity, and the classifier network outputs the final recognition results. Experimental results have shown that the accuracy of the proposed RMFSN for the public datasets UCI-HAR, WISDM, and OPPORTUNITY are 98.13%, 98.35%, and 93.89%, respectively. In comparison with existing advanced methods, the proposed RMFSN could achieve higher accuracy while requiring fewer model parameters.


Assuntos
Atividades Humanas , Dispositivos Eletrônicos Vestíveis , Humanos , Reconhecimento Psicológico , Tecnologia
3.
J Vasc Interv Radiol ; 33(4): 427-435.e4, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-34915166

RESUMO

PURPOSE: To identify differences in mortality or length of hospital stay for mothers treated with uterine artery embolization (UAE) or hysterectomy for severe postpartum hemorrhage (PPH), as well as to analyze whether geographic or clinical determinants affected the type of therapy received. MATERIALS AND METHODS: This National Inpatient Sample study from 2005 to 2017 included all patients with live-birth deliveries. Severe PPH was defined as PPH that required transfusion, hysterectomy, or UAE. Propensity score weighting-adjusted demographic, maternal, and delivery risk factors were used to assess mortality and prolonged hospital stay. RESULTS: Of 9.8 million identified live births, PPH occurred in 31.0 per 1,000 cases. The most common intervention for PPH was transfusion (116.4 per 1,000 cases of PPH). Hysterectomy was used more frequently than UAE (20.4 vs 12.9 per 1,000 cases). The following factors predicted that hysterectomy would be used more commonly than UAE: previous cesarean delivery, breech fetal position, placenta previa, transient hypertension during pregnancy without pre-eclampsia, pre-existing hypertension without pre-eclampsia, pre-existing hypertension with pre-eclampsia, unspecified maternal hypertension, and gestational diabetes (all P < .001). Delivery risk factors associated with greater utilization of hysterectomy over UAE included postterm pregnancy, premature rupture of membranes, cervical laceration, forceps vaginal delivery, and shock (all P < .001). There was no difference in mortality between hysterectomy and UAE. After balancing demographic, maternal, and delivery risk factors, the odds of prolonged hospital stay were 0.38 times lower with UAE than hysterectomy (P < .001). CONCLUSIONS: Despite similar mortality and shorter hospital stays, UAE is used far less than hysterectomy in the management of severe PPH.


Assuntos
Hemorragia Pós-Parto , Embolização da Artéria Uterina , Feminino , Humanos , Histerectomia/efeitos adversos , Pacientes Internados , Hemorragia Pós-Parto/etiologia , Hemorragia Pós-Parto/terapia , Gravidez , Estudos Retrospectivos , Embolização da Artéria Uterina/efeitos adversos
4.
J Am Chem Soc ; 143(44): 18559-18570, 2021 11 10.
Artigo em Inglês | MEDLINE | ID: mdl-34723505

RESUMO

"Enthalpy-Entropy Compensation Effect" (EECE) is ubiquitous in chemical reactions; however, such an EECE has been rarely explored in biomimetic oxidation reactions. In this study, six manganese(IV)-oxo complexes bearing electron-rich and -deficient porphyrins are synthesized and investigated in various oxidation reactions, such as hydrogen atom transfer (HAT), oxygen atom transfer (OAT), and electron-transfer (ET) reactions. First, all of the six Mn(IV)-oxo porphyrins are highly reactive in the HAT, OAT, and ET reactions. Interestingly, we have observed a reversed reactivity in the HAT and OAT reactions by the electron-rich and -deficient Mn(IV)-oxo porphyrins, depending on reaction temperatures, but not in the ET reactions; the electron-rich Mn(IV)-oxo porphyrins are more reactive than the electron-deficient Mn(IV)-oxo porphyrins at high temperature (e.g., 0 °C), whereas at low temperature (e.g., -60 °C), the electron-deficient Mn(IV)-oxo porphyrins are more reactive than the electron-rich Mn(IV)-oxo porphyrins. Such a reversed reactivity between the electron-rich and -deficient Mn(IV)-oxo porphyrins depending on reaction temperatures is rationalized with EECE; that is, the lower is the activation enthalpy, the more negative is the activation entropy, and vice versa. Interestingly, a unified linear correlation between the activation enthalpies and the activation entropies is observed in the HAT and OAT reactions of the Mn(IV)-oxo porphyrins. Moreover, from the previously reported HAT reactions of nonheme Fe(IV)-oxo complexes, a linear correlation between the activation enthalpies and the activation entropies is also observed. To the best of our knowledge, we report the first detailed mechanistic study of EECE in the oxidation reactions by synthetic high-valent metal-oxo complexes.

5.
J Am Chem Soc ; 143(36): 14613-14621, 2021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34469154

RESUMO

Water nucleophilic attack (WNA) on high-valent terminal Mn-oxo species is proposed for O-O bond formation in natural and artificial water oxidation. Herein, we report an electrocatalytic water oxidation reaction with MnIII tris(pentafluorophenyl)corrole (1) in propylene carbonate (PC). O2 was generated at the MnV/IV potential with hydroxide, but a more anodic potential was required to evolve O2 with only water. With a synthetic MnV(O) complex of 1, a second-order rate constant, k2(OH-), of 7.4 × 103 M-1 s-1 was determined in the reaction of the MnV(O) complex of 1 with hydroxide, whereas its reaction with water occurred much more slowly with a k2(H2O) value of 4.4 × 10-3 M-1 s-1. This large reactivity difference of MnV(O) with hydroxide and water is consistent with different electrocatalytic behaviors of 1 with these two substrates. Significantly, during the electrolysis of 1 with water, a MnIV-peroxo species was identified with various spectroscopic methods, including UV-vis, electron paramagnetic resonance, and infrared spectroscopy. Isotope-labeling experiments confirmed that both O atoms of this peroxo species are derived from water, suggesting the involvement of the WNA mechanism in water oxidation by a Mn complex. Density functional theory calculations suggested that the nucleophilic attack of hydroxide on MnV(O) and also WNA to 1e--oxidized MnV(O) are feasibly involved in the catalytic cycles but that direct WNA to MnV(O) is not likely to be the main O-O bond formation pathway in the electrocatalytic water oxidation by 1.

6.
J Cell Mol Med ; 24(22): 12980-12993, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33002329

RESUMO

Epilepsy is a chronic brain disease characterized by recurrent seizures. Circular RNA (circRNA) is a novel family of endogenous non-coding RNAs that have been proposed to regulate gene expression. However, there is a lack of data on the role of circRNA in epilepsy. In this study, the circRNA profiles were evaluated by microarray analysis. In total, 627 circRNAs were up-regulated, whereas 892 were down-regulated in the hippocampus in mice with kainic acid (KA)-induced epileptic seizures compared with control. The expression of circHivep2 was significantly down-regulated in hippocampus tissues of mice with KA-induced epileptic seizures and BV-2 microglia cells upon KA treatment. Bioinformatics analysis predicted that circHivep2 interacts with miR-181a-5p to regulate SOCS2 expression, which was validated using a dual-luciferase reporter assay. Moreover, overexpression of circHivep2 significantly inhibited KA-induced microglial activation and the expression of inflammatory factors in vitro, which was blocked by miR-181a-5p, whereas circHivep2 knockdown further induced microglia cell activation and the release of pro-inflammatory proteins in BV-2 microglia cells after KA treatment. The application of circHivep2+ exosomes derived from adipose-derived stem cells (ADSCs) exerted significant beneficial effects on the behavioural seizure scores of mice with KA-induced epilepsy compared to control exosomes. The circHivep2+ exosomes also inhibited microglial activation, the expression of inflammatory factors, and the miR-181a-5p/SOCS2 axis in vivo. Our results suggest that circHivep2 regulates microglia activation in the progression of epilepsy by interfering with miR-181a-5p to promote SOCS2 expression, indicating that circHivep2 may serve as a therapeutic tool to prevent the development of epilepsy.


Assuntos
Proteínas de Ligação a DNA/genética , Inflamação/tratamento farmacológico , MicroRNAs/metabolismo , Microglia/efeitos dos fármacos , RNA Circular/genética , Convulsões/metabolismo , Proteínas Supressoras da Sinalização de Citocina/metabolismo , Adipócitos/metabolismo , Animais , Biotinilação , Linhagem Celular , Epilepsia/metabolismo , Exossomos/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Hipocampo/metabolismo , Hibridização in Situ Fluorescente , Ácido Caínico , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Análise de Sequência com Séries de Oligonucleotídeos , RNA Longo não Codificante/genética , Convulsões/induzido quimicamente , Transdução de Sinais
7.
J Am Chem Soc ; 142(47): 19879-19884, 2020 11 25.
Artigo em Inglês | MEDLINE | ID: mdl-33186008

RESUMO

We report that Mn(III)-iodosylarene porphyrins, [MnIII(Porp)(sArIO)]+, are capable of activating the C-H bonds of hydrocarbons, including unactivated alkanes such as cyclohexane, with unprecedented reactivities, such as a low kinetic isotope effect, a saturation behavior of reaction rates, and no electronic effect of porphyrin ligands on the reactivities of [MnIII(Porp)(sArIO)]+. In oxygen atom transfer (OAT) reactions, the sulfoxidation of para-X-substituted thioanisoles by [MnIII(Porp)(sArIO)]+ affords a very unusual behavior in the Hammett plot with the saturation behavior of reaction rates and no electronic effect of porphyrin ligands on reactivities. The reactivities and mechanisms of [MnIII(Porp)(sArIO)]+ are then compared with those of the corresponding MnIV(Porp)(O) complex. The present study reports the first example of highly reactive Mn(III)-iodosylarene porphyrins with unprecedented reactivities in C-H bond activation and OAT reactions.

8.
Cancer Cell Int ; 20: 41, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32042268

RESUMO

Pancreatic cancer (PC) is one of the leading causes of cancer-related deaths worldwide. Due to the shortage of effective biomarkers for predicting survival and diagnosing PC, the underlying mechanism is still intensively investigated but poorly understood. Long noncoding RNAs (lncRNAs) provide biological functional diversity and complexity in protein regulatory networks. Scientific studies have revealed the emerging functions and regulatory roles of lncRNAs in PC behaviors. It is worth noting that some in-depth studies have revealed that lncRNAs are significantly associated with the initiation and progression of PC. As lncRNAs have good properties for both diagnostic and prognostic prediction due to their translation potential, we herein address the current understanding of the multifaceted roles of lncRNAs as regulators in the molecular mechanism of PC. We also discuss the possibility of using lncRNAs as survival biomarkers and their contributions to the development of targeted therapies based on the literature. The present review, based on what we know about current research findings, may help us better understand the roles of lncRNAs in PC.

9.
J Am Chem Soc ; 141(31): 12187-12191, 2019 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-31337211

RESUMO

We report that Mn(IV)-oxo porphyrin complexes, MnIV(O)(TMP) (1) and MnIV(O)(TDCPP) (2), are capable of activating the C-H bonds of hydrocarbons, including unactivated alkanes such as cyclohexane, via an oxygen non-rebound mechanism. Interestingly, 1 with an electron-rich porphyrin is more reactive than 2 with an electron-deficient porphyrin at a high temperature (e.g., 0 °C). However, at a low temperature (e.g., -40 °C), the reactivity of 1 and 2 is reversed, showing that 2 is more reactive than 1. To the best of our knowledge, the present study reports the first example of highly reactive Mn(IV)-oxo porphyrins and their temperature-dependent reactivity in C-H bond activation reactions.

10.
Int J Cancer ; 145(4): 952-961, 2019 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-30694558

RESUMO

Glioblastomas (GBMs) and lower-grade gliomas (LGGs) are the most common malignant brain tumors. Despite extensive studies that have suggested that there are differences between the two in terms of clinical profile and treatment, their distinctions on a molecular level had not been systematically analyzed. Here, we investigated the distinctions between GBM and LGG based on multidimensional data, including somatic mutations, somatic copy number variants (SCNVs), gene expression, lncRNA expression and DNA methylation levels. We found that GBM patients had a higher mutation frequency and SCNVs than LGG patients. Differential mRNAs and lncRNAs between GBM and LGG were identified and a differential mRNA-lncRNA network was constructed and analyzed. We also discovered some differential DNA methylation sites could distinguish between GBM and LGG samples. Finally, we identified some key GBM- and LGG-specific genes featuring multiple-level molecular alterations. These specific genes participate in diverse functions; moreover, GBM-specific genes are enriched in the glioma pathway. Overall, our studies explored the distinctions between GMB and LGG using a comprehensive genomics approach that may provide novel insights into studying the mechanism and treatment of brain tumors.


Assuntos
Neoplasias Encefálicas/genética , Glioblastoma/genética , Glioma/genética , Variações do Número de Cópias de DNA/genética , Metilação de DNA/genética , Expressão Gênica/genética , Humanos , Mutação/genética , RNA Longo não Codificante/genética , RNA Mensageiro/genética
11.
Cell Mol Neurobiol ; 39(3): 461-470, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30790096

RESUMO

Temporal lobe epilepsy (TLE) is associated with neurodegeneration, often leading to hippocampal sclerosis (HS). Type 1 HS, which is characterized by severe neuronal loss and gliosis predominantly in regions CA1 and CA4, is the most common subtype and is associated with the best prognosis according to the ILAE classification system. MiRNAs participate in the biological processes underlying many nervous system diseases, including epilepsy. However, the miRNA expression profile of HS ILAE type 1 is not completely understood. A total of 14 patients were identified as having the ILAE subtype, as determined by NeuN immunohistochemistry (ILAE type 1 = 7; no-HS = 7). Next-generation sequencing and reverse transcription polymerase chain reaction technology were used to validate the dysregulated miRNAs. Bioinformatics analysis of the predicted target genes was conducted using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses. In total, 1643 mature miRNAs were detected in this study, along with 5 miRNAs that were upregulated and 2 miRNAs that were downregulated in the type 1 group. Bioinformatics analysis showed that 1545 target genes were predicted using the miRDB and Targetscan databases and that these predicted genes showed enrichment in pathways associated with nucleic acid binding, intracellular and cellular macromolecule metabolic processes, and the PI3K-Akt signaling pathway. This study is the first to report the miRNA expression profile of HS ILAE type 1 compared with those of no-HS. These results provide new insights into the neuronal loss pathology of type 1 HS.


Assuntos
Epilepsia do Lobo Temporal/genética , Perfilação da Expressão Gênica , Hipocampo/patologia , MicroRNAs/genética , Adolescente , Adulto , Estudos de Casos e Controles , Criança , Biologia Computacional , Feminino , Humanos , Masculino , MicroRNAs/metabolismo , Reprodutibilidade dos Testes , Esclerose , Adulto Jovem
12.
Inorg Chem ; 58(21): 14842-14852, 2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31621303

RESUMO

Mononuclear nonheme manganese complexes are highly efficient catalysts in the catalytic oxidation of hydrocarbons by hydrogen peroxide in the presence of carboxylic acids. Although high-valent Mn(V)-oxo complexes have been proposed as the active oxidants that afford high regio-, stereo-, and enantioselectivities in the catalytic oxidation reactions, the importance of the spin state (e.g., S = 0 or 1) of the proposed Mn(V)-oxo species is an area that requires further study. In the present study, we have theoretically demonstrated that a mononuclear nonheme Mn(V)-oxo species with an S = 1 ground spin state is the active oxidant that effects the stereo- and enantioselective alkane hydroxylation reaction; it is noted that synthetic octahedral Mn(V)-oxo complexes, characterized spectroscopically and/or structurally, possess an S = 0 spin state and are sluggish oxidants. In an experimental approach, we have investigated the catalytic hydroxylation of alkanes by a mononuclear nonheme Mn(II) complex, [(S-PMB)MnII]2+, and H2O2 in the presence of carboxylic acids; alcohol is the major product with high stereo- and enantioselectivities. A synthetic Mn(IV)-oxo complex, [(S-PMB)MnIV(O)]2+, is inactive in C-H bond activation reactions, ruling out the Mn(IV)-oxo species as an active oxidant. DFT calculations have shown that a Mn(V)-oxo species with an S = 1 spin state, [(S-PMB)MnV(O)(OAc)]2+, is highly reactive and capable of oxygenating the C-H bond via oxygen rebound mechanism; we propose that the triplet spin state of the Mn(V)-oxo species results from the consequence of breaking the equatorial symmetry due to the binding of an equatorial oxygen from an acetate ligand. Thus, the present study reports that, different from the previously reported S = 0 Mn(V)-oxo species, Mn(V)-oxo species with a triplet ground spin state are highly reactive oxidants that are responsible for the regio-, stereo-, and enantioselectivities in the catalytic hydroxylation of alkanes by mononuclear nonheme manganese complexes and terminal oxidants.

13.
Sensors (Basel) ; 19(18)2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31487947

RESUMO

Fog computing has recently emerged as an extension of cloud computing in providing high-performance computing services for delay-sensitive Internet of Things (IoT) applications. By offloading tasks to a geographically proximal fog computing server instead of a remote cloud, the delay performance can be greatly improved. However, some IoT applications may still experience considerable delays, including queuing and computation delays, when huge amounts of tasks instantaneously feed into a resource-limited fog node. Accordingly, the cooperation among geographically close fog nodes and the cloud center is desired in fog computing with the ever-increasing computational demands from IoT applications. This paper investigates a workload allocation scheme in an IoT-fog-cloud cooperation system for reducing task service delay, aiming at satisfying as many as possible delay-sensitive IoT applications' quality of service (QoS) requirements. To this end, we first formulate the workload allocation problem in an IoT-edge-cloud cooperation system, which suggests optimal workload allocation among local fog node, neighboring fog node, and the cloud center to minimize task service delay. Then, the stability of the IoT-fog-cloud queueing system is theoretically analyzed with Lyapunov drift plus penalty theory. Based on the analytical results, we propose a delay-aware online workload allocation and scheduling (DAOWA) algorithm to achieve the goal of reducing long-term average task serve delay. Theoretical analysis and simulations have been conducted to demonstrate the efficiency of the proposal in task serve delay reduction and IoT-fog-cloud queueing system stability.

14.
Cell Physiol Biochem ; 50(3): 924-935, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30355947

RESUMO

BACKGROUND/AIMS: Increasing evidence shows that reprogramming of energy metabolism is a hallmark of cancer. Considering the emergence of microRNAs as crucial modulators of cancer, this study aimed to better understand the molecular mechanisms of miR-124 in regulating glycolysis in human pancreatic cancer. METHODS: RT-PCR was used to investigate the expression of monocarboxylate transporters (MCTs) in pancreatic ductal adenocarcinoma (PDAC) patient samples and the PANC-1 cell line. A public database and immunochemistry were used for comprehensive analysis of MCT1 expression. The targeting of MCT1 by miR-124 was predicted by software and validated for the MCT1 3'-UTR by dual-luciferase reporter analysis. Cell proliferation, apoptosis, migration, xenografting, and the intracellular pH and L-lactate levels were assessed. Hypoxia-inducible factor-α (HIF-1α) and lactate dehydrogenase A (LDH-A) expression levels were determined by RT-PCR and western blotting. RESULTS: MCT1 expression was higher in PDAC tissue than in normal tissue. Inhibition of MCT1 affected lactate metabolism, resulting in a higher intracellular pH and less proliferation of PANC-1 cells. MCT1 was the target gene of miR-124. In in vitro experiments, miR-124 inhibited the glycolytic activity of PANC-1 cells by targeting MCT1, further decreasing the tumor phenotype by increasing the intracellular pH through LDH-A and HIF-1α. In in vivo experiments, overexpression of miR-124 and silencing of MCT1 significantly inhibited tumor growth. CONCLUSION: miR-124 inhibits the progression of PANC-1 by targeting MCT1 in the lactate metabolic pathway. Our findings provide novel evidence for further functional studies of miR-124, which might be useful for future therapeutic approaches to PDAC.


Assuntos
MicroRNAs/metabolismo , Transportadores de Ácidos Monocarboxílicos/metabolismo , Simportadores/metabolismo , Regiões 3' não Traduzidas , Animais , Antagomirs/metabolismo , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/patologia , Linhagem Celular Tumoral , Proliferação de Células , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Isoenzimas/genética , Isoenzimas/metabolismo , L-Lactato Desidrogenase/genética , L-Lactato Desidrogenase/metabolismo , Lactato Desidrogenase 5 , Lactatos/metabolismo , Camundongos , Camundongos Nus , MicroRNAs/antagonistas & inibidores , MicroRNAs/genética , Transportadores de Ácidos Monocarboxílicos/antagonistas & inibidores , Transportadores de Ácidos Monocarboxílicos/genética , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Simportadores/antagonistas & inibidores , Simportadores/genética
15.
Inorg Chem ; 57(16): 10232-10240, 2018 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-30080409

RESUMO

Mn(III)-iodosylarene porphyrin adducts, [Mn(III)(ArIO)(Porp)]+, were synthesized by reacting electron-deficient Mn(III) porphyrin complexes with iodosylarene (ArIO) at -60 °C and characterized using various spectroscopic methods. The [Mn(III)(ArIO)(Porp)]+ species were then investigated in the epoxidation of olefins under stoichiometric conditions. In the epoxidation of olefins by the Mn(III)-iodosylarene porphyrin species, epoxide was formed as the sole product with high chemoselectivities and stereoselectivities. For example, cyclohexene oxide was formed exclusively with trace amounts of allylic oxidation products; cis- and trans-stilbenes were oxidized to the corresponding cis- and trans-stilbene oxides, respectively. In the catalytic epoxidation of cyclohexene by an electron-deficient Mn(III) porphyrin complex and sPhIO at low temperature (e.g., -60 °C), the Mn(III)-iodosylarene porphyrin species was evidenced as the active oxidant that effects the olefin epoxidation to give epoxide as the product. However, at high temperature (e.g., 0 °C) or in the case of using an electron-rich manganese(III) porphyrin catalyst, allylic oxidation products, along with cyclohexene oxide, were yielded, indicating that the active oxidant(s) was not the Mn(III)-iodosylarene adduct but probably high-valent Mn-oxo species in the catalytic reactions. We also report the conversion of the Mn(III)-iodosylarene porphyrins to high-valent Mn-oxo porphyrins under various conditions, such as at high temperature, with electron-rich porphyrin ligand, and in the presence of base (OH-). The present study reports the first example of spectroscopically well-characterized Mn(III)-iodosylarene porphyrin species being an active oxidant in the stoichiometric and catalytic oxidation reactions. Other aspects, such as one oxidant versus multiple oxidants debate, also were discussed.

16.
J Am Chem Soc ; 139(44): 15858-15867, 2017 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-29056043

RESUMO

Activation of dioxygen (O2) in enzymatic and biomimetic reactions has been intensively investigated over the past several decades. More recently, O-O bond formation, which is the reverse of the O2-activation reaction, has been the focus of current research. Herein, we report the O2-activation and O-O bond formation reactions by manganese corrole complexes. In the O2-activation reaction, Mn(V)-oxo and Mn(IV)-peroxo intermediates were formed when Mn(III) corroles were exposed to O2 in the presence of base (e.g., OH-) and hydrogen atom (H atom) donor (e.g., THF or cyclic olefins); the O2-activation reaction did not occur in the absence of base and H atom donor. Moreover, formation of the Mn(V)-oxo and Mn(IV)-peroxo species was dependent on the amounts of base present in the reaction solution. The role of the base was proposed to lower the oxidation potential of the Mn(III) corroles, thereby facilitating the binding of O2 and forming a Mn(IV)-superoxo species. The putative Mn(IV)-superoxo species was then converted to the corresponding Mn(IV)-hydroperoxo species by abstracting a H atom from H atom donor, followed by the O-O bond cleavage of the putative Mn(IV)-hydroperoxo species to form a Mn(V)-oxo species. We have also shown that addition of hydroxide ion to the Mn(V)-oxo species afforded the Mn(IV)-peroxo species via O-O bond formation and the resulting Mn(IV)-peroxo species reverted to the Mn(V)-oxo species upon addition of proton, indicating that the O-O bond formation and cleavage reactions between the Mn(V)-oxo and Mn(IV)-peroxo complexes are reversible. The present study reports the first example of using the same manganese complex in both O2-activation and O-O bond formation reactions.


Assuntos
Manganês/química , Oxigênio/química , Porfirinas/química , Alcenos/química , Hidrogênio/química , Cinética , Oxirredução
17.
Cell Physiol Biochem ; 43(2): 636-643, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28942448

RESUMO

BACKGROUND: MiR-134 is enriched in dendrites of hippocampal neurons and plays crucial roles in the progress of epilepsy. The present study aims to investigate the effects of antagomirs targeting miroRNA-134 (Ant-134) on limk1 expression and the binding of miR-134 and limk1 in experimental seizure. METHODS: Status epilepticus (SE) rat model was established by lithium chloride-pilocarpine injection and was treated with Ant-134 by intracerebroventricular injection. Low Mg2+-exposed primary neurons were used as an in vitro model of SE. The expression of miR-134 was determined using real-time PCR. Protein expressions of limk1 and cofilin were determined by Western blotting. Luciferase reporter assay was used to examine the binding between miR-134 and limk1 3'-untranslated region. RESULTS: The expression of miR-134 was markedly enhanced in hippocampus of the SE rats and low Mg2+-exposed neurons. Ant-134 increased the expression of limk1 and reduced the expression of cofilin in the SE hippocampus and Low Mg2+-exposed neurons. In addition, luciferase reporter assay confirmed that miR-134 bound limk1 3'-UTR. MiR-134 overexpression inhibited limk1 mRNA and protein expressions in neurons. CONCLUSION: Blockage of miR-134 upregulates limk1 expression and downregulated cofilin expression in hippocampus of the SE rats. This mechanism may contribute to the neuroprotective effects of Ant-134.


Assuntos
Antagomirs/uso terapêutico , Quinases Lim/genética , MicroRNAs/genética , Convulsões/terapia , Estado Epiléptico/terapia , Regulação para Cima , Animais , Células Cultivadas , Terapia Genética , Hipocampo/metabolismo , Hipocampo/patologia , Masculino , Neurônios/metabolismo , Neurônios/patologia , Ratos Sprague-Dawley , Convulsões/genética , Convulsões/patologia , Estado Epiléptico/genética , Estado Epiléptico/patologia
18.
Tumour Biol ; 37(9): 12039-12047, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27177902

RESUMO

Glioblastoma multiform is one of the most common and most aggressive brain tumors in humans. The molecular and cellular mechanisms responsible for the onset and progression of GBM are elusive and controversial. The function of tumor suppressor candidate 3 (TUSC3) has not been previously characterized in GBM. TUSC3 was originally identified as part of an enzyme complex involved in N-glycosylation of proteins, but was recently implicated as a potential tumor suppressor gene in a variety of cancer types. In this study, we demonstrated that the expression levels of TUSC3 were downregulated in both GBM tissues and cells, and also found that overexpression of TUSC3 inhibits GBM cell proliferation and invasion. In addition, the effects of increased levels of methylation on the TUSC3 promoter were responsible for decreased expression of TUSC3 in GBM. Finally, we determined that TUSC3 regulates proliferation and invasion of GBM cells by inhibiting the activity of the Akt signaling pathway.


Assuntos
Neoplasias Encefálicas/patologia , Glioblastoma/patologia , Proteínas de Membrana/fisiologia , Proteínas Proto-Oncogênicas c-akt/fisiologia , Transdução de Sinais/fisiologia , Proteínas Supressoras de Tumor/fisiologia , Neoplasias Encefálicas/etiologia , Linhagem Celular Tumoral , Proliferação de Células , Metilação de DNA , Glioblastoma/etiologia , Glicosilação , Humanos , Proteínas de Membrana/genética , Invasividade Neoplásica , Regiões Promotoras Genéticas , Proteínas Supressoras de Tumor/genética
19.
Biochem Biophys Res Commun ; 460(3): 670-7, 2015 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-25817794

RESUMO

Glioblastoma development is often associated with alteration in the activity and expression of cell cycle regulators, such as cyclin-dependent kinases (CKDs) and cyclins, resulting in aberrant cell proliferation. Recent studies have highlighted the pivotal roles of miRNAs in controlling the development and growth of glioblastoma. Here, we provide evidence for a function of miR-340 in the inhibition of glioblastoma cell proliferation. We found that miR-340 is downregulated in human glioblastoma tissue samples and several established glioblastoma cell lines. Proliferation and neurosphere formation assays revealed that miR-340 plays an oncosuppressive role in glioblastoma, and that its ectopic expression causes significant defect in glioblastoma cell growth. Further, using bioinformatics, luciferase assay and western blot, we found that miR-340 specifically targets the 3'UTRs of CDK6, cyclin-D1 and cyclin-D2, leading to the arrest of glioblastoma cells in the G0/G1 cell cycle phase. Confirming these results, we found that re-introducing CDK6, cyclin-D1 or cyclin-D2 expression partially, but significantly, rescues cells from the suppression of cell proliferation and cell cycle arrest mediated by miR-340. Collectively, our results demonstrate that miR-340 plays a tumor-suppressive role in glioblastoma and may be useful as a diagnostic biomarker and/or a therapeutic avenue for glioblastoma.


Assuntos
Neoplasias Encefálicas/patologia , Proliferação de Células , Ciclina D1/genética , Ciclina D2/genética , Quinase 6 Dependente de Ciclina/genética , Glioblastoma/patologia , MicroRNAs/fisiologia , Sequência de Bases , Linhagem Celular Tumoral , Primers do DNA , Humanos , Reação em Cadeia da Polimerase em Tempo Real
20.
BMC Biotechnol ; 15: 53, 2015 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-26054393

RESUMO

BACKGROUND: The lipopeptide antibiotic iturin A is an attractive biopesticide with the potential to replace chemical-based pesticides for controlling plant pathogens. However, its industrial fermentation has not been realized due to the high production costs and low product concentrations. This study aims to enhance iturin A production by performing a novel fermentation process with effective glucose feeding control using rapeseed meal as a low-cost nitrogen source. RESULTS: We demonstrated that continuous and significant enhancement of iturin A production could be achieved by a novel two-stage glucose-feeding strategy with a stepwise decrease in feeding rate. Using this strategy, the ratio of spores to total cells could be maintained at a desirable/stable level of 0.80-0.86, and the reducing sugar concentration could be controlled at a low level of 2-3 g/L so that optimal substrate balance could be maintained throughout the feeding phase. As a result, the maximum iturin A concentration reached 1.12 g/L, which was two-fold higher than that of batch culture. CONCLUSIONS: This is the first report which uses control of the glucose supply to improve iturin A production by fed-batch fermentation and identifies some important factors necessary to realize industrial iturin A production. This approach may also enhance the production of other useful secondary metabolites by Bacillus subtilis.


Assuntos
Bacillus subtilis/metabolismo , Brassica rapa/metabolismo , Glucose/metabolismo , Peptídeos Cíclicos/biossíntese , Técnicas de Cultura Celular por Lotes , Agentes de Controle Biológico/metabolismo , Reatores Biológicos/microbiologia , Fermentação , Nitrogênio/metabolismo
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