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1.
J Cell Sci ; 135(15)2022 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-35775474

RESUMO

Accelerated aerobic glycolysis is a distinctive metabolic property of cancer cells that confers dependency on glucose for survival. However, the therapeutic strategies targeting this vulnerability are still inefficient and have unacceptable side effects in clinical trials. Therefore, developing biomarkers to predict therapeutic efficacy would be essential to improve the selective targeting of cancer cells. Here, we found that cell lines that are sensitive to glucose deprivation have high expression of cystine/glutamate antiporter xCT (also known as SLC7A11). We found that cystine uptake and glutamate export through xCT contributed to rapid NADPH depletion under glucose deprivation. This collapse of the redox system oxidized and inactivated AMP-activated protein kinase (AMPK), a major regulator of metabolic adaptation, resulting in a metabolic catastrophe and cell death. Although this phenomenon was prevented by pharmacological or genetic inhibition of xCT, overexpression of xCT sensitized resistant cancer cells to glucose deprivation. Taken together, these findings suggest a novel crosstalk between AMPK and xCT that links metabolism and signal transduction, and reveal a metabolic vulnerability to glucose deprivation in cancer cells expressing high levels of xCT.


Assuntos
Cistina , Neoplasias , Proteínas Quinases Ativadas por AMP/metabolismo , Sistema y+ de Transporte de Aminoácidos/genética , Sistema y+ de Transporte de Aminoácidos/metabolismo , Linhagem Celular Tumoral , Cistina/metabolismo , Glucose/metabolismo , Ácido Glutâmico/metabolismo , Neoplasias/genética , Oxirredução
2.
Nanotechnology ; 34(20)2023 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-36745914

RESUMO

HfO2-based ferroelectric thin films have attracted significant interest for semiconductor device applications due to their compatibility with complementary metal oxide semiconductor (CMOS) technology. One of the benefits of HfO2-based ferroelectric thin films is their ability to be scaled to thicknesses as low as 10 nm while retaining their ferroelectric properties; a feat that has been difficult to accomplish with conventional perovskite-based ferroelectrics using CMOS-compatible processes. However, reducing the thickness limit of HfO2-based ferroelectric thin films below the sub 5 nm thickness regime while preserving their ferroelectric property remains a formidable challenge. This is because both the structural factors of HfO2, including polymorphism and orientation, and the electrical factors of HfO2-based devices, such as the depolarization field, are known to be highly dependent on the HfO2thickness. Accordingly, when the thickness of HfO2drops below 5 nm, these factors will become even more crucial. In this regard, the size effect of HfO2-based ferroelectric thin films is thoroughly discussed in the present review. The impact of thickness on the ferroelectric property of HfO2-based thin films and the electrical performance of HfO2-based ferroelectric semiconductor devices, such as ferroelectric random-access-memory, ferroelectric field-effect-transistor, and ferroelectric tunnel junction, is extensively discussed from the perspective of fundamental theory and experimental results. Finally, recent developments and reports on achieving ferroelectric HfO2at sub-5 nm thickness regime and their applications are discussed.

3.
Nanotechnology ; 34(12)2023 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-36538824

RESUMO

Hf0.5Zr0.5O2(HZO) thin films are promising candidates for non-volatile memory and other related applications due to their demonstrated ferroelectricity at the nanoscale and compatibility with Si processing. However, one reason that HZO has not been fully scaled into industrial applications is due to its deleterious wake-up and fatigue behavior which leads to an inconsistent remanent polarization during cycling. In this study, we explore an interfacial engineering strategy in which we insert 1 nm Al2O3interlayers at either the top or bottom HZO/TiN interface of sequentially deposited metal-ferroelectric-metal capacitors. By inserting an interfacial layer while limiting exposure to the ambient environment, we successfully introduce a protective passivating layer of Al2O3that provides excess oxygen to mitigate vacancy formation at the interface. We report that TiN/HZO/TiN capacitors with a 1 nm Al2O3at the top interface demonstrate a higher remanent polarization (2Pr∼ 42µC cm-2) and endurance limit beyond 108cycles at a cycling field amplitude of 3.5 MV cm-1. We use time-of-flight secondary ion mass spectrometry, energy dispersive spectroscopy, and grazing incidence x-ray diffraction to elucidate the origin of enhanced endurance and leakage properties in capacitors with an inserted 1 nm Al2O3layer. We demonstrate that the use of Al2O3as a passivating dielectric, coupled with sequential ALD fabrication, is an effective means of interfacial engineering and enhances the performance of ferroelectric HZO devices.

4.
Small ; 18(2): e2104944, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34802184

RESUMO

The charging process of secondary batteries is always associated with a large volume expansion of the alloying anodes, which in many cases, develops high compressive residual stresses near the propagating interface. This phenomenon causes a significant reduction in the rate performance of the anodes and is detrimental to the development of fast-charging batteries. However, for the Na-Sn battery system, the residual stresses that develop near the interface are not stored, but are relieved by the generation of high-density dislocations in crystalline Sn. Direct-contact diffusion experiments show that these dislocations facilitate the preferential transport of Na and accelerate the Na diffusion into crystalline Sn at ultrafast rates via "dislocation-pipe diffusion". Advanced analyses are performed to observe the evolution of atomic-scale structures while measuring the distribution and magnitude of residual stresses near the interface. In addition, multi-scale simulations that combined classical molecular dynamics and first-principles calculations are performed to explain the structural origins of the ultrafast diffusion rates observed in the Na-Sn system. These findings not only address the knowledge gaps regarding the relationship between pipe diffusion and the diffusivity of carrier ions but also provide guidelines for the appropriate selection of anode materials for use in fast-charging batteries.

5.
Ecotoxicol Environ Saf ; 241: 113843, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36068765

RESUMO

Microplastics (MPs), due to their impacts on the ecosystem and their integration into the food web either through trophic transfer or ingestion directly from the ambient environment, are an emerging class of environmental contaminants posing a great threat to marine organisms. Most reports on the toxic effects of MPs exclusively focus on bioaccumulation, oxidative stress, pathological damage, and metabolic disturbance in fish. However, the collected information on fish immunity in response to MPs is poorly defined. In particular, little is known regarding mucosal immunity and the role of mucins. In this study, marine medaka (Oryzias melastigma) larvae were exposed to 6.0 µm beads of polystyrene microplastics (PS-MPs) at three environmentally relevant concentrations (102 particles/L, 104 particles/L, and 106 particles/L) for 14 days. The experiment was carried out to explore the developmental and behavioural indices, the transcriptional profiles of mucins, pro-inflammatory, immune, metabolism and antioxidant responses related genes, as well as the accumulation of PS-MPs in larvae. The results revealed that PS-MPs were observed in the gastrointestinal tract, with a concentration- and exposure time-dependent manner. No significant difference in the larval mortality was found between the treatment groups and the control, whereas the body length of larvae demonstrated a significant reduction at 106 particles/L on 14 days post-hatching. The swimming behaviour of the larvae became hyperactive under exposure to 104 and 106 particles/L PS-MPs. In addition, PS-MP exposure significantly up-regulated the mucin gene transcriptional levels of muc7-like and muc13-like, however down-regulated the mucin gene expression levels of heg1, muc2, muc5AC-like and muc13. The immune- and inflammation and metabolism-relevant genes (jak, stat-3, il-6, il-1ß, tnf-а, ccl-11, nf-κb, and sod) were significantly induced by PS-MPs at 104 and 106 particles/L compared to the control. Taken together, this study suggests that PS-MPs induced inflammation response and might obstruct the immune functions and retarded the growth of the marine medaka larvae even at environmentally relevant concentrations.


Assuntos
Oryzias , Poluentes Químicos da Água , Animais , Ecossistema , Imunidade , Inflamação , Larva , Microplásticos/toxicidade , Mucinas/genética , Mucinas/metabolismo , Oryzias/metabolismo , Plásticos/toxicidade , Poliestirenos/metabolismo , Poliestirenos/toxicidade , Natação , Poluentes Químicos da Água/análise
6.
Eur Radiol ; 31(10): 7594-7604, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33876298

RESUMO

OBJECTIVES: According to LI-RADS, a major discriminating feature between hepatocellular carcinoma (HCC) and non-HCC malignancies is the subtype of arterial phase hyperenhancement (APHE). The aim of this study was to investigate whether APHE subtypes are consistent across multi-arterial phase (mHAP) MRI acquisitions while evaluating reader agreement. Secondarily, we investigated factors that may affect reader agreement for APHE subtype. METHODS: In this retrospective study, consecutive patients with liver cirrhosis and focal observations who underwent mHAP were included. Five radiologists reviewed MR images in 2 reading sessions. In reading session 1, individual AP series were reviewed and scored for presence of APHE and subtype. In reading session 2, readers scored observations' major and ancillary features and LI-RADS category in the complete MRI examination. Reader agreement was calculated using Fleiss' kappa for binary outcomes and Kendall's coefficient of concordance for LI-RADS categories. Univariate mixed effects logistic regressions were performed to investigate factors affecting agreement. RESULTS: In total, 61 patients with 77 focal observations were analyzed. Of observations unanimously scored as having APHE, 27.7% showed both rim and nonrim subtypes on mHAP. Inter-reader agreement for APHE subtype ranged from 0.49 (95% CI: 0.33, 0.64) to 0.57 (95% CI: 0.40, 0.74) between reading sessions. Observation size had a trend level effect on rim APHE agreement (p = 0.052). CONCLUSION: Approximately 1/3 of observations demonstrated inconsistent APHE subtype during mHAP acquisition. Small lesions were particularly challenging. Further guidance on APHE subtype classification, especially when applied to mHAP, could be a focus of LI-RADS refinement. KEY POINTS: • In a cohort of patients at risk for HCC, 28% of the observations showed inconsistent arterial phase hyperenhancement (APHE) subtypes (rim and nonrim) on multi-arterial phase imaging according to the majority score of 5 independent readers. • Inconsistent APHE subtypes may challenge reliable imaging diagnosis, i.e., LI-RADS categorization, of focal liver observations in patients at risk for HCC.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Carcinoma Hepatocelular/diagnóstico por imagem , Meios de Contraste , Humanos , Fígado , Neoplasias Hepáticas/diagnóstico por imagem , Imageamento por Ressonância Magnética , Estudos Retrospectivos , Sensibilidade e Especificidade
7.
Nanotechnology ; 32(48)2021 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-34407525

RESUMO

Ferroelectric random-access memory (FRAM) based on conventional ferroelectric materials is a non-volatile memory with fast read/write operations, high endurance, and 10 years of data retention time. However, it suffers from destructive read-out operation and lack of CMOS compatibility. HfO2-based ferroelectric tunnel junctions (FTJ) may compensate for the shortcomings of FRAM by its CMOS compatibility, fast operation speed, and non-destructive readout operation. In this study, we investigate the effect of ferroelectric and interface film thickness on the tunneling electroresistance or ON/OFF current ratio of the Hf0.5Zr0.5O2/Al2O3based FTJ device. Integrating a thick ferroelectric layer (i.e. 12 nm Hf0.5Zr0.5O2) with a thin interface layer (i.e. 1 nm Al2O3) resulted in an ON/OFF current ratio of 78. Furthermore, to elucidate the relationship between ON/OFF current ratio and interfacial properties, the Hf0.5Zr0.5O2-Al2O3films and Ge-Al2O3interfaces are examined via time-of-flight secondary ion mass spectrometry depth profiling mode. A bilayer oxide heterostructure (Hf0.5Zr0.5O2/Al2O3) is deposited by atomic layer deposition (ALD) on the Ge substrate. The ON/OFF current ratio is enhanced by an order of magnitude when the Hf0.5Zr0.5O2film deposition mode is changed from exposure (H2O) ALD to sequential plasma (sequential O2-H2) ALD. Moreover, the interfacial engineering approach based on thein situALD H2-plasma surface pre-treatment of Ge increases the ON/OFF current ratio from 9 to 38 by reducing the interfacial trap density state at the Ge-Al2O3interface and producing Al2O3with fewer oxygen vacancies as compared to the wet etch (HF + H2O rinse) treatment of the Ge substrate. This study provides evidence of strong coupling between Hf0.5Zr0.5O2and Al2O3films in controlling the ON/OFF current ratio of the FTJ.

8.
J Nanosci Nanotechnol ; 18(3): 2158-2161, 2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-29448735

RESUMO

Up-conversion phosphors have attracted considerable attention because of their applications in solid-state lasers, optical communications, flat-panel displays, photovoltaic cells, and biological labels. Among them, NaYF4 is reported as one of the most efficient hosts for infrared to visible photon up-conversion of Yb3+ and Er3+ ions. However, a low-temperature method is required for industrial scale fabrication of photonic and optoelectronic devices on flexible organic substrates. In this study, hexagonal ß-NaYF4: 3 mol% Yb3+, 3 mol% Er3+ up-conversion phosphor using Ca2+ was prepared by chemical solution method. Then, we synthesized a nanostructured organo-silicon compound from methyl tri-methoxysilane and 3-glycidoxy-propyl-trimethoxy-silane. The transmittance of the organo-silicon compound was found to be over 90% in the wavelength range of 400~1500 nm. Then we prepared a fluoride-based phosphor paste by mixing the organo-silicon compound with Na(Ca)YF4:Yb3+, Er3+. Subsequently, this paste was coated on polyethylene terephthalate, followed by heat-treatment at 120 °C. The visible emission of the infrared detection card was found to be at 655 nm and 661 nm an excitation wavelength of 980 nm.

9.
Undersea Hyperb Med ; 45(6): 689-693, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-31158938

RESUMO

INTRODUCTION: Carbon monoxide (CO) poisoning is one of the most common forms of intoxication around the world. One of the complications associated with CO exposure is direct toxicity to the skeletal muscles. Though compartment syndrome induced by CO intoxication is rare, it is a well-known complication. In this study, we present a case of CO poisoning in a patient who developed compartment syndrome in his forearm. CASE REPORT: A 22-year-old man was found unconscious in a motel where a briquette had burned. He was later diagnosed with rhabdomyolysis associated with CO poisoning. After he regained consciousness, he experienced difficulty in moving his left arm, with sensory impairment in the same arm. He was diagnosed with compartment syndrome, and an emergency fasciotomy was performed. One month later, electromyography was performed which revealed left median, ulnar, radial, and musculocutaneous nerve palsy. DISCUSSION: Compartment syndrome induced by CO intoxication is rare but is a well-known complication. Compartment syndrome is a limb-threatening and life-threatening condition. If untreated, the pressure in the muscle may rise, which can lead to tissue necrosis. Generally, nerve paralysis does not occur in CO poisoning. In our case, it occurred as median, ulnar, radial and musculocutaneous nerve palsy. CONCLUSION: Side effects of CO poisoning can be extant, especially for those who are unconscious since they cannot express pain, numbness, and motor weakness. It is important to not overlook compartment syndrome, to double-check whether there is swelling, change in skin color, or skin firmness in extremities, and to observe the patient closely.


Assuntos
Intoxicação por Monóxido de Carbono/complicações , Síndromes Compartimentais/etiologia , Antebraço , Intoxicação por Monóxido de Carbono/diagnóstico , Síndromes Compartimentais/cirurgia , Fasciotomia/métodos , Humanos , Masculino , Neuropatia Mediana/etiologia , Nervo Musculocutâneo , Doenças do Sistema Nervoso Periférico/etiologia , Rabdomiólise/etiologia , Neuropatias Ulnares/etiologia , Adulto Jovem
10.
Neurochem Res ; 40(7): 1438-47, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25998887

RESUMO

In our previous study, we demonstrated that nodakenin, a coumarin compound isolated from Angelica decursiva, ameliorates learning and memory impairments induced by scopolamine. In the present study, we investigated the effects of nodakenin on the cognitive function in the normal naïve mice in a passive avoidance task, and the results showed that nodakenin significantly increased the latency time in normal naïve mice. In addition, sub-chronic administration of nodakenin increased the number of 5-bromo-2-deoxyuridine (BrdU)-positive cells in the hippocampal dentate gyrus (DG) region. The percentage of BrdU and NeuN (neuronal cell marker)-immunopositive cells was also significantly increased by the nodakenin administration. Western blotting results showed that the expression levels of phosphorylated protein kinase B (Akt) and phosphorylated glycogen synthase kinase-3ß (GSK-3ß) were significantly increased in hippocampal tissue by sub-chronic nodakenin administration. These findings suggest that the sub-chronic administration of nodakenin enhances adult hippocampal neurogenesis in the DG region via Akt-GSK-3ß signaling and this increase may be associated with nodakenin's positive effect on cognitive processing.


Assuntos
Cognição/efeitos dos fármacos , Cumarínicos/farmacologia , Glucosídeos/farmacologia , Hipocampo/efeitos dos fármacos , Neurogênese/efeitos dos fármacos , Animais , Animais Recém-Nascidos , Aprendizagem da Esquiva , Diferenciação Celular/efeitos dos fármacos , Quinase 3 da Glicogênio Sintase/metabolismo , Glicogênio Sintase Quinase 3 beta , Hipocampo/enzimologia , Hipocampo/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos ICR , Proteínas Proto-Oncogênicas c-akt/metabolismo
11.
Biol Pharm Bull ; 37(7): 1207-13, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24989012

RESUMO

Alzheimer's disease, a neurodegenerative disorder, is characterized by progressive cognitive impairment associated with the disruption of cholinergic neurotransmission. The aim of the present study was to evaluate the effect of α- or ß-amyrin, a type of pentacyclic triterpene, on the cognitive impairment induced by scopolamine, a muscarinic acetylcholine receptor antagonist. To measure the abilities of various types of learning and memory, we conducted step-through passive avoidance task. Scopolamine induced deficits in learning and memory processes in mice, which were antagonized by a single administration of α-amyrin (2 or 4 mg/kg) or ß-amyrin (4 mg/kg), respectively. Additionally, in vitro analysis revealed that acetylcholinesterase activity was inhibited by ß-amyrin, but not by α-amyrin. Furthermore, Western blot analysis revealed that the expression levels of phosphorylated extracellular signal-regulated kinase 1/2 (pERK) and phosphorylated glycogen synthase kinase-3ß (pGSK-3ß) were significantly enhanced by a single administration of α- and ß-amyrin in the hippocampus. Finally, the memory ameliorating effects of α- or ß-amyrin on the scopolamine-induced cognitive impairments were significantly blocked by ERK inhibitor U0126. The present study suggests that α- and ß-amyrin may ameliorate the cognitive impairment induced by hypocholinergic neurotransmission via the activation of ERK as well as GSK-3ß signaling.


Assuntos
Comportamento Animal/efeitos dos fármacos , Transtornos Cognitivos/tratamento farmacológico , Antagonistas Muscarínicos/farmacologia , Ácido Oleanólico/análogos & derivados , Escopolamina/farmacologia , Acetilcolinesterase/química , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Transtornos Cognitivos/induzido quimicamente , Transtornos Cognitivos/enzimologia , Transtornos Cognitivos/psicologia , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Quinase 3 da Glicogênio Sintase/metabolismo , Glicogênio Sintase Quinase 3 beta , Hipocampo/efeitos dos fármacos , Hipocampo/enzimologia , Hipocampo/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Memória/efeitos dos fármacos , Camundongos Endogâmicos ICR , Ácido Oleanólico/administração & dosagem , Ácido Oleanólico/uso terapêutico
12.
J Emerg Med ; 46(5): 643-9, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24262059

RESUMO

BACKGROUND: The effectiveness of chest compressions for cardiopulmonary resuscitation (CPR) is affected by the rescuer's position with respect to the patient. In hospitals, chest compressions are typically performed while standing beside the patient, who is placed on a bed. STUDY OBJECTIVES: To compare the effectiveness of chest compressions, performed on a bed during 2 min of CPR, among three different rescuer positions: standing, on a footstool, or kneeling on the bed. METHODS: We performed a crossover randomized simulation trial. Participants were recruited from among students in the Department of Paramedics from July to August 2011. Thirty-eight participants were enrolled, and they performed chest compressions on a mannequin for 2 min in each of the three different positions, with a 1-week interval between each position. RESULTS: The number of adequate compressions (depth > 50 mm) and the mean compression depth were significantly greater in the kneeling and footstool positions than in the standing position, but there was no significant difference between the kneeling and footstool positions. There were no significant differences in the compression rate, the percentage of correctly released compressions, and the percentage of compressions performed using the correct hand position among the three rescuer positions. CONCLUSION: The mean compression depth and the number of adequate compressions were greater for both the kneeling and footstool positions than for the standing position during 2 min of CPR. We recommend kneeling on a bed or standing on a footstool as the rescuer positions during hospital CPR on a bed.


Assuntos
Reanimação Cardiopulmonar/métodos , Manequins , Postura , Adulto , Reanimação Cardiopulmonar/normas , Estudos Cross-Over , Feminino , Humanos , Masculino , Simulação de Paciente , Adulto Jovem
13.
Nat Cancer ; 5(5): 701-715, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38698089

RESUMO

Metabolic changes contribute to cancer initiation and progression through effects on cancer cells, the tumor microenvironment and whole-body metabolism. Alterations in serine metabolism and the control of one-carbon cycles have emerged as critical for the development of many tumor types. In this Review, we focus on the mitochondrial folate cycle. We discuss recent evidence that, in addition to supporting nucleotide synthesis, mitochondrial folate metabolism also contributes to metastasis through support of antioxidant defense, mitochondrial protein synthesis and the overflow of excess formate. These observations offer potential therapeutic opportunities, including the modulation of formate metabolism through dietary interventions and the use of circulating folate cycle metabolites as biomarkers for cancer detection.


Assuntos
Ácido Fólico , Mitocôndrias , Neoplasias , Humanos , Ácido Fólico/metabolismo , Neoplasias/metabolismo , Mitocôndrias/metabolismo , Animais , Formiatos/metabolismo , Microambiente Tumoral , Metástase Neoplásica
14.
Elife ; 132024 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-39037770

RESUMO

Bats have unique characteristics compared to other mammals, including increased longevity and higher resistance to cancer and infectious disease. While previous studies have analyzed the metabolic requirements for flight, it is still unclear how bat metabolism supports these unique features, and no study has integrated metabolomics, transcriptomics, and proteomics to characterize bat metabolism. In this work, we performed a multi-omics data analysis using a computational model of metabolic fluxes to identify fundamental differences in central metabolism between primary lung fibroblast cell lines from the black flying fox fruit bat (Pteropus alecto) and human. Bat cells showed higher expression levels of Complex I components of electron transport chain (ETC), but, remarkably, a lower rate of oxygen consumption. Computational modeling interpreted these results as indicating that Complex II activity may be low or reversed, similar to an ischemic state. An ischemic-like state of bats was also supported by decreased levels of central metabolites and increased ratios of succinate to fumarate in bat cells. Ischemic states tend to produce reactive oxygen species (ROS), which would be incompatible with the longevity of bats. However, bat cells had higher antioxidant reservoirs (higher total glutathione and higher ratio of NADPH to NADP) despite higher mitochondrial ROS levels. In addition, bat cells were more resistant to glucose deprivation and had increased resistance to ferroptosis, one of the characteristics of which is oxidative stress. Thus, our studies revealed distinct differences in the ETC regulation and metabolic stress responses between human and bat cells.


Assuntos
Quirópteros , Fibroblastos , Quirópteros/metabolismo , Humanos , Fibroblastos/metabolismo , Animais , Metabolômica , Espécies Reativas de Oxigênio/metabolismo , Proteômica/métodos , Linhagem Celular , Consumo de Oxigênio , Multiômica
15.
Exp Neurobiol ; 32(4): 259-270, 2023 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-37749927

RESUMO

Circadian rhythm is a 24-hour cycle of behavioral and physiological changes. Disrupted sleep-wake patterns and circadian dysfunction are common in patients of Alzheimer Disease (AD) and are closely related with neuroinflammation. However, it is not well known how circadian rhythm of immune cells is altered during the progress of AD. Previously, we found presenilin 2 (Psen2) N141I mutation, one of familial AD (FAD) risk genes, induces hyperimmunity through the epigenetic repression of REV-ERBα expression in microglia and bone marrow-derived macrophage (BMDM) cells. Here, we investigated whether repression of REV-ERBα is associated with dysfunction of immune cell-endogenous or central circadian rhythm by analyses of clock genes expression and cytokine secretion, bioluminescence recording of rhythmic PER2::LUC expression, and monitoring of animal behavioral rhythm. Psen2 N141I mutation down-regulated REV-ERBα and induced selective over-production of IL-6 (a well-known clock-dependent cytokine) following the treatment of toll-like receptor (TLR) ligands in microglia, astrocytes, and BMDM. Psen2 N141I mutation also lowered amplitude of intrinsic daily oscillation in these immune cells representatives of brain and periphery. Of interest, however, the period of daily rhythm remained intact in immune cells. Furthermore, analyses of the central clock and animal behavioral rhythms revealed that central clock remained normal without down-regulation of REV-ERBα. These results suggest that Psen2 N141I mutation induces hyperimmunity mainly through the suppression of REV-ERBα in immune cells, which have lowered amplitude but normal period of rhythmic oscillation. Furthermore, our data reveal that central circadian clock is not affected by Psen2 N141I mutation.

16.
Cell Rep ; 42(6): 112562, 2023 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-37245210

RESUMO

Mitochondrial 10-formyltetrahydrofolate (10-formyl-THF) is utilized by three mitochondrial enzymes to produce formate for nucleotide synthesis, NADPH for antioxidant defense, and formyl-methionine (fMet) to initiate mitochondrial mRNA translation. One of these enzymes-aldehyde dehydrogenase 1 family member 2 (ALDH1L2)-produces NADPH by catabolizing 10-formyl-THF into CO2 and THF. Using breast cancer cell lines, we show that reduction of ALDH1L2 expression increases ROS levels and the production of both formate and fMet. Both depletion of ALDH1L2 and direct exposure to formate result in enhanced cancer cell migration that is dependent on the expression of the formyl-peptide receptor (FPR). In various tumor models, increased ALDH1L2 expression lowers formate and fMet accumulation and limits metastatic capacity, while human breast cancer samples show a consistent reduction of ALDH1L2 expression in metastases. Together, our data suggest that loss of ALDH1L2 can support metastatic progression by promoting formate and fMet production, resulting in enhanced FPR-dependent signaling.


Assuntos
Neoplasias da Mama , Formiatos , Oxirredutases atuantes sobre Doadores de Grupo CH-NH , Feminino , Humanos , Neoplasias da Mama/metabolismo , Formiatos/metabolismo , Metionina , NADP , Espécies Reativas de Oxigênio , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/metabolismo
17.
ACS Appl Mater Interfaces ; 14(37): 42232-42244, 2022 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-36069477

RESUMO

Hafnia-zirconia (HfO2-ZrO2) solid solution thin films have emerged as viable candidates for electronic applications due to their compatibility with Si technology and demonstrated ferroelectricity at the nanoscale. The oxygen source in atomic layer deposition (ALD) plays a crucial role in determining the impurity concentration and phase composition of HfO2-ZrO2 within metal-ferroelectric-metal devices, notably at the Hf0.5Zr0.5O2 /TiN interface. The interface characteristics of HZO/TiN are fabricated via sequential no-atmosphere processing (SNAP) with either H2O or O2-plasma to study the influence of oxygen source on buried interfaces. Time-of-flight secondary ion mass spectrometry reveals that HZO films grown via O2-plasma promote the development of an interfacial TiOx layer at the bottom HZO/TiN interface. The presence of the TiOx layer leads to the development of 111-fiber texture in HZO as confirmed by two-dimensional X-ray diffraction (2D-XRD). Structural and chemical differences between HZO films grown via H2O or O2-plasma were found to strongly affect electrical characteristics such as permittivity, leakage current density, endurance, and switching kinetics. While HZO films grown via H2O yielded a higher remanent polarization value of 25 µC/cm2, HZO films grown via O2-plasma exhibited a comparable Pr of 21 µC/cm2 polarization and enhanced field cycling endurance limit by almost 2 orders of magnitude. Our study illustrates how oxygen sources (O2-plasma or H2O) in ALD can be a viable way to engineer the interface and properties in HZO thin films.

18.
Nat Commun ; 13(1): 1972, 2022 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-35418126

RESUMO

Hyperimmunity drives the development of Alzheimer disease (AD). The immune system is under the circadian control, and circadian abnormalities aggravate AD progress. Here, we investigate how an AD-linked mutation deregulates expression of circadian genes and induces cognitive decline using the knock-in (KI) mice heterozygous for presenilin 2 N141I mutation. This mutation causes selective overproduction of clock gene-controlled cytokines through the DNA hypermethylation-mediated repression of REV-ERBα in innate immune cells. The KI/+ mice are vulnerable to otherwise innocuous, mild immune challenges. The antipsychotic chlorpromazine restores the REV-ERBα level by normalizing DNA methylation through the inhibition of PI3K/AKT1 pathway, and prevents the overexcitation of innate immune cells and cognitive decline in KI/+ mice. These results highlight a pathogenic link between this AD mutation and immune cell overactivation through the epigenetic suppression of REV-ERBα.


Assuntos
Repressão Epigenética , Membro 1 do Grupo D da Subfamília 1 de Receptores Nucleares , Presenilina-2/genética , Animais , Ritmo Circadiano/fisiologia , Imunidade , Camundongos , Mutação , Membro 1 do Grupo D da Subfamília 1 de Receptores Nucleares/metabolismo
19.
Clin Exp Emerg Med ; 8(1): 65-70, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33845525

RESUMO

OBJECTIVE: Intractable massive oronasal bleeding can become a life-threatening condition. The success rate of conventional bleeding control methods other than transarterial embolization (TAE) is not expected to be high. We investigated the efficacy of Sengstaken-Blakemore tube (SBT) balloon tamponade in patients with sustained and intractable oronasal bleeding secondary to facial injury. METHODS: This study is a retrospective chart review from traumatic patients with sustained and intractable oronasal bleeding who were admitted to the emergency center of Ajou University Hospital and Soonchunhyang University Bucheon Hospital from January 2014 to December 2016. RESULTS: Twelve patients were included in the study, of whom nine (75%) were male. The median age was 31 years (range, 20-73 years). Bleeding was controlled in 11 of the 12 patients (91.7%) either temporarily or definitively. One patient without hemostasis underwent TAE. TAE was performed in an additional three patients out of the 11 patients with hemostasis who experienced continued nasal bleeding after the removal of SBTs. There were no complications from performing the procedure. CONCLUSION: Using SBTs as a hemostatic tool will aid patients with life-threatening intractable oronasal bleeding. Furthermore, this method may be used in patients with continual and intractable oronasal bleeding after facial trauma as a bridging procedure from the emergency department or the intensive care unit to the interventional radiology.

20.
Mol Brain ; 13(1): 88, 2020 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-32513210

RESUMO

Microglia are macrophages resident in the central nervous system. C-X3-C motif chemokine receptor 1 (CX3CR1) is a Gαi-coupled seven-transmembrane protein exclusively expressed in the mononuclear phagocyte system including microglia, as well as intestinal and kidney macrophages. Cx3cr1CreERT2 mice express Cre recombinase in a tamoxifen-inducible manner and have been widely used to delete target genes in microglia, since microglia are long-lived cells and outlive peripheral macrophages, which continuously turn over and lose their gene modification over time. ATG7 is an E1-like enzyme that plays an essential role in two ubiquitin-like reactions, ATG12-ATG5 conjugation and LC3-lipidation in autophagy. To study the role of ATG7 in adult microglia, we generated Cx3cr1CreERT2:Atg7fl/fl mice and deleted Atg7 at the age of 8 weeks, and found induction of intestinal adhesion. Since intestinal adhesion is caused by excessive inflammation, these results suggest that deletion of Atg7 in intestinal macrophages even for a short time results in inflammation that cannot be rescued by replenishment with wild-type intestinal macrophages. Our finding suggests that, depending on the roles of the gene, Cx3cr1-Cre-mediated gene deletion may yield unanticipated physiological outcomes outside the central nervous system, and careful necropsy is necessary to assure the microglia-specific roles of the target gene.


Assuntos
Proteína 7 Relacionada à Autofagia/metabolismo , Receptor 1 de Quimiocina CX3C/metabolismo , Deleção de Genes , Integrases/metabolismo , Intestinos/patologia , Aderências Teciduais/genética , Animais , Camundongos , Tamoxifeno/farmacologia
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