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1.
J Neurosci ; 43(46): 7730-7744, 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-37726169

RESUMO

NR2D subunit-containing NMDA receptors (NMDARs) gradually disappear during brain maturation but can be recruited by pathophysiological stimuli in the adult brain. Here, we report that 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intoxication recruited NR2D subunit-containing NMDARs that generated an Mg2+-resistant tonic NMDA current (INMDA) in dopaminergic (DA) neurons in the midbrain of mature male mice. MPTP selectively generated an Mg2+-resistant tonic INMDA in DA neurons in the substantia nigra pars compacta (SNpc) and ventral tegmental area (VTA). Consistently, MPTP increased NR2D but not NR2B expression in the midbrain regions. Pharmacological or genetic NR2D interventions abolished the generation of Mg2+-resistant tonic INMDA in SNpc DA neurons, and thus attenuated subsequent DA neuronal loss and gait deficits in MPTP-treated mice. These results show that extrasynaptic NR2D recruitment generates Mg2+-resistant tonic INMDA and exacerbates DA neuronal loss, thus contributing to MPTP-induced Parkinsonism. The state-dependent NR2D recruitment could be a novel therapeutic target for mitigating cell type-specific neuronal death in neurodegenerative diseases.SIGNIFICANCE STATEMENT NR2D subunit-containing NMDA receptors (NMDARs) are widely expressed in the brain during late embryonic and early postnatal development, and then downregulated during brain maturation and preserved at low levels in a few regions of the adult brain. Certain stimuli can recruit NR2D subunits to generate tonic persistent NMDAR currents in nondepolarized neurons in the mature brain. Our results show that MPTP intoxication recruits NR2D subunits in midbrain dopaminergic (DA) neurons, which leads to tonic NMDAR current-promoting dopaminergic neuronal death and consequent abnormal gait behavior in the MPTP mouse model of Parkinson's disease (PD). This is the first study to indicate that extrasynaptic NR2D recruitment could be a target for preventing neuronal death in neurodegenerative diseases.


Assuntos
Doença de Parkinson , Receptores de N-Metil-D-Aspartato , Camundongos , Animais , Masculino , Receptores de N-Metil-D-Aspartato/metabolismo , N-Metilaspartato/metabolismo , Dopamina/metabolismo , Neurônios Dopaminérgicos/metabolismo , Doença de Parkinson/metabolismo , Camundongos Endogâmicos C57BL , 1-Metil-4-Fenil-1,2,3,6-Tetra-Hidropiridina/farmacologia , 1-Metil-4-Fenil-1,2,3,6-Tetra-Hidropiridina/metabolismo , Substância Negra/metabolismo
2.
Brain ; 146(7): 2957-2974, 2023 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-37062541

RESUMO

Reactive astrogliosis is a hallmark of Alzheimer's disease (AD). However, a clinically validated neuroimaging probe to visualize the reactive astrogliosis is yet to be discovered. Here, we show that PET imaging with 11C-acetate and 18F-fluorodeoxyglucose (18F-FDG) functionally visualizes the reactive astrocyte-mediated neuronal hypometabolism in the brains with neuroinflammation and AD. To investigate the alterations of acetate and glucose metabolism in the diseased brains and their impact on the AD pathology, we adopted multifaceted approaches including microPET imaging, autoradiography, immunohistochemistry, metabolomics, and electrophysiology. Two AD rodent models, APP/PS1 and 5xFAD transgenic mice, one adenovirus-induced rat model of reactive astrogliosis, and post-mortem human brain tissues were used in this study. We further curated a proof-of-concept human study that included 11C-acetate and 18F-FDG PET imaging analyses along with neuropsychological assessments from 11 AD patients and 10 healthy control subjects. We demonstrate that reactive astrocytes excessively absorb acetate through elevated monocarboxylate transporter-1 (MCT1) in rodent models of both reactive astrogliosis and AD. The elevated acetate uptake is associated with reactive astrogliosis and boosts the aberrant astrocytic GABA synthesis when amyloid-ß is present. The excessive astrocytic GABA subsequently suppresses neuronal activity, which could lead to glucose uptake through decreased glucose transporter-3 in the diseased brains. We further demonstrate that 11C-acetate uptake was significantly increased in the entorhinal cortex, hippocampus and temporo-parietal neocortex of the AD patients compared to the healthy controls, while 18F-FDG uptake was significantly reduced in the same regions. Additionally, we discover a strong correlation between the patients' cognitive function and the PET signals of both 11C-acetate and 18F-FDG. We demonstrate the potential value of PET imaging with 11C-acetate and 18F-FDG by visualizing reactive astrogliosis and the associated neuronal glucose hypometablosim for AD patients. Our findings further suggest that the acetate-boosted reactive astrocyte-neuron interaction could contribute to the cognitive decline in AD.


Assuntos
Doença de Alzheimer , Camundongos , Humanos , Ratos , Animais , Doença de Alzheimer/metabolismo , Fluordesoxiglucose F18/metabolismo , Astrócitos/metabolismo , Radioisótopos de Carbono/metabolismo , Gliose/diagnóstico por imagem , Encéfalo/patologia , Tomografia por Emissão de Pósitrons/métodos , Ácido gama-Aminobutírico/metabolismo
3.
Biochem Biophys Res Commun ; 641: 102-109, 2023 01 22.
Artigo em Inglês | MEDLINE | ID: mdl-36525924

RESUMO

The premature death and degeneration of striatal neurons are typical hallmarks of HtrA2-inactivated motor neuron degeneration 2 (mnd2) mice. Although HtrA2 has been extensively studied in relation to the regulation of apoptosis using mnd2 mice, little is known about the other physiological functions of HtrA2. In this study, we found that the skin color of wild-type (WT) and mnd2 mice was black and pink on postnatal day 32. Using histological and molecular assays (i.e., assessing the activation of MAPK and expression patterns of PCNA), we demonstrated that this differential skin color change is consistent with the delay in the telogen - to - anagen phase of the hair cycle in mnd2 mice. We also examined adipocytes in the subcutaneous skin layer, finding that HtrA2 inactivation leads to the growth retardation of adipocytes, thereby delaying the hair cycle of mnd2 mice. Collectively, these findings show for the first time that HtrA2 plays an essential role in regulating the adipogenesis-associated hair cycle.


Assuntos
Proteínas Mitocondriais , Serina Endopeptidases , Animais , Camundongos , Apoptose , Cabelo/metabolismo , Serina Peptidase 2 de Requerimento de Alta Temperatura A/genética , Proteínas Mitocondriais/metabolismo , Serina Endopeptidases/genética , Serina Endopeptidases/metabolismo
4.
Biochem Biophys Res Commun ; 638: 84-93, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36442236

RESUMO

Aggregation and misfolding of α-Synuclein (α-Syn), a causative agent for Parkinson's disease (PD), and oxidative stress are tightly implicated in the pathogenesis of PD. Although more than 20 genes including HtrA2 have been identified as causative genes for PD, the molecular mechanisms underlying the pathophysiological functions between HtrA2 and α-Syn in the pathogenesis of PD remain unclear. This study shows that HtrA2 serine protease selectively recognizes and interacts with the NAC region of α-Syn. Interestingly, we found that HtrA2 causes proteolysis of α-Syn to prevent mitochondrial accumulation of α-Syn, thereby inhibiting the production of reactive oxygen species (ROS) in the mitochondria. We have further demonstrated that HtrA2 knockdown promotes α-Syn-mediated mitochondrial ROS production, thereby activating microglial cells. This study is the first to demonstrate that the HtrA2/α-Syn cellular partner may play a crucial role in the pathogenesis of PD and provide new insights into the pathological processes and effective therapeutic strategies for PD.


Assuntos
Doença de Parkinson , alfa-Sinucleína , Humanos , alfa-Sinucleína/genética , Espécies Reativas de Oxigênio , Microglia/patologia , Doença de Parkinson/genética , Doença de Parkinson/patologia , Serina Peptidase 2 de Requerimento de Alta Temperatura A/genética , Mitocôndrias/patologia
5.
Cancer Cell Int ; 23(1): 219, 2023 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-37759302

RESUMO

BACKGROUND: Recently, natural killer (NK) cells emerged as a treatment option for various solid tumors. However, the immunosuppressive tumor immune microenvironment (TIME) can reduce the cytotoxic ability of NK cells in pancreatic ductal adenocarcinoma. Cancer-associated fibroblasts within the tumor stroma can suppress immune surveillance by dysregulating factors involved in the cellular activity of NK cells. Herein, the effect of activated pancreatic stellate cells (aPSCs) on NK cell-mediated anticancer efficacy under three-dimensional (3D) coculture conditions was investigated. METHODS: 3D cocultures of PANC-1 tumor spheroids (TSs) with aPSCs and NK-92 cells in a collagen matrix were optimized to identify the occurring cellular interactions and differential cytokine profiles in conditioned media using microchannel chips. PANC-1 TSs and aPSCs were indirectly cocultured, whereas NK-92 cells were allowed to infiltrate the TS channel using convective medium flow. RESULTS: Coculture with aPSCs promoted PANC-1 TSs growth and suppressed the antitumor cytotoxic effects of NK-92 cells. Mutual inhibition of cellular activity without compromising migration ability was observed between aPSCs and NK-92 cells. Moreover, the reduced killing activity of NK-92 cells was found to be related with reduced granzyme B expression in NK cells. CONCLUSIONS: Herein, a novel TIME-on-chip model based on the coculture of PANC-1 TSs, aPSCs, and NK-92 cells was described. This model may be useful for studying the detailed mechanisms underlying NK cells dysregulation and for exploring future therapeutic interventions to restore NK cell activity in the tumor microenvironment.

6.
Mol Psychiatry ; 2022 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-35902630

RESUMO

There is a compelling need to develop disease-modifying therapies for Alzheimer's disease (AD), the most common neuro-degenerative disorder. Together with recent progress in vector development for efficiently targeting the central nervous system, gene therapy has been suggested as a potential therapeutic modality to overcome the limited delivery of conventional types of drugs to and within the damaged brain. In addition, given increasing evidence of the strong link between glia and AD pathophysiology, therapeutic targets have been moving toward those addressing glial cell pathology. Nurr1 and Foxa2 are transcription/epigenetic regulators that have been reported to cooperatively regulate inflammatory and neurotrophic response in glial cells. In this study, we tested the therapeutic potential of Nurr1 and Foxa2 gene delivery to treat AD symptoms and pathologies. A series of functional, histologic, and transcriptome analyses revealed that the combined expression of Nurr1 and Foxa2 substantially ameliorated AD-associated amyloid ß and Tau proteinopathy, cell senescence, synaptic loss, and neuro-inflammation in multiple in vitro and in vivo AD models. Intra-cranial delivery of Nurr1 and Foxa2 genes using adeno-associated virus (AAV) serotype 9 improved the memory and cognitive function of AD model mice. The therapeutic benefits of gene delivery were attained mainly by correcting pathologic glial function. These findings collectively indicate that AAV9-mediated Nurr1 and Foxa2 gene transfer could be an effective disease-modifying therapy for AD.

7.
Int J Mol Sci ; 24(3)2023 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-36768816

RESUMO

Parkinson's disease (PD) is a neurodegenerative disorder with typical motor symptoms. Recent studies have suggested that excessive GABA from reactive astrocytes tonically inhibits dopaminergic neurons and reduces the expression of tyrosine hydroxylase (TH), the key dopamine-synthesizing enzyme, in the substantia nigra pars compacta (SNpc). However, the expression of DOPA decarboxylase (DDC), another dopamine-synthesizing enzyme, is relatively spared, raising a possibility that the live but non-functional TH-negative/DDC-positive neurons could be the therapeutic target for rescuing PD motor symptoms. However, due to the absence of a validated DDC-specific promoter, manipulating DDC-positive neuronal activity has not been tested as a therapeutic strategy for PD. Here, we developed an AAV vector expressing mCherry under rat DDC promoter (AAV-rDDC-mCherry) and validated the specificity in the rat SNpc. Modifying this vector, we expressed hM3Dq (Gq-DREADD) under DDC promoter in the SNpc and ex vivo electrophysiologically validated the functionality. In the A53T-mutated alpha-synuclein overexpression model of PD, the chemogenetic activation of DDC-positive neurons in the SNpc significantly alleviated the parkinsonian motor symptoms and rescued the nigrostriatal TH expression. Altogether, our DDC-promoter will allow dopaminergic neuron-specific gene delivery in rodents. Furthermore, we propose that the activation of dormant dopaminergic neurons could be a potential therapeutic strategy for PD.


Assuntos
Doença de Parkinson , Transtornos Parkinsonianos , Ratos , Animais , Neurônios Dopaminérgicos/metabolismo , Dopamina/metabolismo , Dopa Descarboxilase/metabolismo , Parte Compacta da Substância Negra/metabolismo , Transtornos Parkinsonianos/metabolismo , Doença de Parkinson/metabolismo , Tirosina 3-Mono-Oxigenase/genética , Tirosina 3-Mono-Oxigenase/metabolismo , Substância Negra/metabolismo
8.
Cell Mol Life Sci ; 78(2): 415-426, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32671427

RESUMO

µ-opioid receptor (MOR) is a class of opioid receptors that is critical for analgesia, reward, and euphoria. MOR is distributed in various brain regions, including the hippocampus, where traditionally, it is believed to be localized mainly at the presynaptic terminals of the GABAergic inhibitory interneurons to exert a strong disinhibitory effect on excitatory pyramidal neurons. However, recent intensive research has uncovered the existence of MOR in hippocampal astrocytes, shedding light on how astrocytic MOR participates in opioid signaling via glia-neuron interaction in the hippocampus. Activation of astrocytic MOR has shown to cause glutamate release from hippocampal astrocytes and increase the excitability of presynaptic axon fibers to enhance the release of glutamate at the Schaffer Collateral-CA1 synapses, thereby, intensifying the synaptic strength and plasticity. This novel mechanism involving astrocytic MOR has been shown to participate in hippocampus-dependent conditioned place preference. Furthermore, the signaling of hippocampal MOR, whose action is sexually dimorphic, is engaged in adult neurogenesis, seizure, and stress-induced memory impairment. In this review, we focus on the two profoundly different hippocampal opioid signaling pathways through either GABAergic interneuronal or astrocytic MOR. We further compare and contrast their molecular and cellular mechanisms and their possible roles in opioid-associated conditioned place preference and other hippocampus-dependent behaviors.


Assuntos
Astrócitos/metabolismo , Ácido Glutâmico/metabolismo , Hipocampo/fisiologia , Interneurônios/metabolismo , Receptores Opioides mu/metabolismo , Transdução de Sinais , Animais , Astrócitos/citologia , Ácido Glutâmico/análise , Hipocampo/citologia , Humanos , Interneurônios/citologia , Receptores Opioides mu/análise , Transmissão Sináptica
9.
Int J Mol Sci ; 23(8)2022 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-35457272

RESUMO

Monoamine oxidase-B (MAOB) has been believed to mediate the degradation of monoamine neurotransmitters such as dopamine. However, this traditional belief has been challenged by demonstrating that it is not MAOB but MAOA which mediates dopamine degradation. Instead, MAOB mediates the aberrant synthesis of GABA and hydrogen peroxide (H2O2) in reactive astrocytes of Parkinson's disease (PD). Astrocytic GABA tonically suppresses the dopaminergic neuronal activity, whereas H2O2 aggravates astrocytic reactivity and dopaminergic neuronal death. Recently discovered reversible MAOB inhibitors reduce reactive astrogliosis and restore dopaminergic neuronal activity to alleviate PD symptoms in rodents. In this perspective, we redefine the role of MAOB for the aberrant suppression and deterioration of dopaminergic neurons through excessive GABA and H2O2 synthesis of reactive astrocytes in PD.


Assuntos
Astrócitos , Monoaminoxidase , Doença de Parkinson , Astrócitos/metabolismo , Dopamina/metabolismo , Humanos , Peróxido de Hidrogênio/metabolismo , Monoaminoxidase/metabolismo , Doença de Parkinson/metabolismo , Ácido gama-Aminobutírico/metabolismo
10.
Glia ; 68(5): 1065-1080, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-31833596

RESUMO

Tonic extrasynaptic GABAA receptor (GABAA R) activation is under the tight control of tonic GABA release from astrocytes to maintain the brain's excitation/inhibition (E/I) balance; any slight E/I balance disturbance can cause serious pathological conditions including epileptic seizures. However, the pathophysiological role of tonic GABA release from astrocytes has not been tested in epileptic seizures. Here, we report that pharmacological or genetic intervention of the GABA-permeable Bestrophin-1 (Best1) channel prevented the generation of tonic GABA inhibition, disinhibiting CA1 pyramidal neuronal firing and augmenting seizure susceptibility in kainic acid (KA)-induced epileptic mice. Astrocyte-specific Best1 over-expression in KA-injected Best1 knockout mice fully restored the generation of tonic GABA inhibition and effectively suppressed seizure susceptibility. We demonstrate for the first time that tonic GABA from reactive astrocytes strongly contributes to the compensatory shift of E/I balance in epileptic hippocampi, serving as a good therapeutic target against altered E/I balance in epileptic seizures.


Assuntos
Astrócitos/metabolismo , Bestrofinas/metabolismo , Hipocampo/metabolismo , Inibição Neural/fisiologia , Convulsões/metabolismo , Ácido gama-Aminobutírico/metabolismo , Animais , Bestrofinas/genética , Ácido Caínico , Camundongos , Camundongos Knockout , Receptores de GABA-A/metabolismo , Convulsões/induzido quimicamente , Convulsões/genética
13.
Biochim Biophys Acta Gen Subj ; 1862(7): 1602-1611, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29631059

RESUMO

BACKGROUND: Regulating apoptosis is a common and essential therapeutic strategy for cancer and neurodegenerative disorders. Based on basic studies of apoptotic mechanisms, various researches have attempted to overcome the pathogenesis of such diseases by activating or inhibiting apoptosis. Generally, the biochemical characteristics of the target molecules should be evaluated along with understanding of their mechanisms of action during drug development. Among apoptotic regulators, XIAP serves as a potent negative regulator to block apoptosis through the inhibition of caspase (CASP)-9 and -3/7. Although XIAP is an attractive target with such apoptotic-modulating property, biochemical and biophysical studies of XIAP are still challenging. METHODS: In this study, the CASP-9 and -3/7 inhibitors XIAP, 242Δ and Δ230 were prepared using the pGEX expression system and biochemically characterized. RESULTS: These inhibitors were expressed in Escherichia coli at a concentration of ≥20 mg/L culture under a native condition with 0.01 mM IPTG induction. Notably, using a simple and rapid affinity purification technique, these CASP-9 and -3/7 inhibitors have been purified, yielding ≥5 mg/L culture at approximately 90% purity. CONCLUSIONS: We have determined that HtrA2 specifically binds to the BIR2 and BIR3 of XIAP at a 1:1 molecular ratio. Moreover, in vitro cell-free CASP-9 and -3/7 activation-apoptosis assays have demonstrated that these purified XIAP proteins dramatically inhibit CASP-9 and -3/7 action. GENERAL SIGNIFICANCE: Our system is suitable for biochemical studies, such as quantitation of the number of molecules acting on the apoptosis regulation, and provides a basis and insights that can be applied to the development of therapeutic agents for neurodegenerative disorders and cancer.


Assuntos
Apoptose/efeitos dos fármacos , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/farmacologia , Caspases/metabolismo , Avaliação Pré-Clínica de Medicamentos , Ativação Enzimática/efeitos dos fármacos , Células HEK293 , Serina Peptidase 2 de Requerimento de Alta Temperatura A/metabolismo , Humanos , Neoplasias/tratamento farmacológico , Doenças Neurodegenerativas/tratamento farmacológico , Ligação Proteica , Domínios Proteicos , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/análise , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/genética , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/isolamento & purificação
14.
J Korean Med Sci ; 33(25): e172, 2018 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-29915523

RESUMO

BACKGROUND: Obesity and related metabolic disorders are growing health challenges worldwide and individuals at military service are not exceptions. The purpose of this study was to examine the prevalence of obesity and metabolic syndrome (MS) in the Korean military and to compare with the general population. METHODS: This was a cross-sectional study of 4,803 young military participants who underwent a corporal health-screening program between October 2013 and October 2014. The National Cholesterol Education Program Adult Treatment Panel III criteria was used to identify MS. We also sampled 1,108 men aged 19-29 years from the Korea National Health and Nutritional Examination Survey from 2010 to 2013 to compare with their military counterparts. RESULTS: The mean age of military participants was 20.8 ± 1.1 years, and 20.6% (n = 988) were obese. The prevalence of MS was 0.8% in military participants, while 7.9% in general population. The risk factors of MS were less prominent among military participants relative to civilians, with the exception of high blood pressure, of which prevalence was higher among military participants (21.5% vs. 18.2%, respectively). In multiple logistic analysis, high physical activity conferred lower odds of MS and obesity in military participants (odds ratios, 0.19 and 0.81, respectively). Age older than 25 years increased risk of most components of MS among civilians. CONCLUSION: The prevalence of obesity and MS is lower in military participants compared with civilians of similar age. Monitoring of high blood pressure and proper stress management are warranted in those at military service.


Assuntos
Síndrome Metabólica/epidemiologia , Militares/estatística & dados numéricos , Obesidade/epidemiologia , Adulto , Povo Asiático , Estudos Transversais , Humanos , Estilo de Vida , Modelos Logísticos , Masculino , Inquéritos Nutricionais , Razão de Chances , Prevalência , República da Coreia/epidemiologia , Adulto Jovem
15.
Int J Mol Sci ; 19(8)2018 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-30042374

RESUMO

The mechanisms underlying the progression to non-alcoholic steatohepatitis (NASH) remain to be elucidated. In the present study, we aimed to identify the proteins involved in the pathogenesis of liver tissue inflammation and to investigate the effects of silibinin, a natural polyphenolic flavonoid, on steatohepatitis. We performed comparative proteomic analysis using methionine and choline-deficient (MCD) diet-induced NASH model mice. Eighteen proteins were identified from the two-dimensional proteomic analysis, which are not only differentially expressed, but also significantly improved, by silibinin treatment. Interestingly, seven of these proteins, including keratin cytoskeletal 8 and 18, peroxiredoxin-4, and protein disulfide isomerase, are known to undergo GlcNAcylation modification, most of which are related to structural and stress-related proteins in NASH model animals. Thus, we primarily focused on how the GlcNAc modification of these proteins is involved in the progression to NASH. Remarkably, silibinin treatment alleviates the severity of hepatic inflammation along with O-GlcNAcylation in steatohepatitis. In particular, the reduction of inflammation by silibinin is due to the inhibition of the O-GlcNAcylation-dependent NF-κB-signaling pathway. Therefore, silibinin is a promising therapeutic agent for hyper-O-GlcNAcylation as well as NASH.


Assuntos
Anti-Inflamatórios/farmacologia , Inflamação/tratamento farmacológico , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Silimarina/farmacologia , beta-N-Acetil-Hexosaminidases/metabolismo , Animais , Anti-Inflamatórios/administração & dosagem , Antioxidantes/administração & dosagem , Antioxidantes/farmacologia , Deficiência de Colina , Humanos , Inflamação/metabolismo , Fígado/patologia , Masculino , Metionina/deficiência , Camundongos , Camundongos Endogâmicos C57BL , NF-kappa B/metabolismo , Hepatopatia Gordurosa não Alcoólica/induzido quimicamente , Hepatopatia Gordurosa não Alcoólica/metabolismo , Peroxirredoxinas/metabolismo , Proteômica , Células RAW 264.7 , Silibina , Silimarina/administração & dosagem
16.
J Prosthet Dent ; 120(6): 969.e1-969.e6, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30545472

RESUMO

STATEMENT OF PROBLEM: Surface glazing and low-temperature degradation (LTD) can affect the mechanical properties of zirconia, which is used to fabricate monolithic ceramic crowns. PURPOSE: The purpose of this in vitro study was to assess the changes in flexural strength of monolithic ceramic crowns fabricated from translucent zirconia due to surface glazing and LTD. MATERIAL AND METHODS: Sixty plates of zirconia (25×4×1.2 mm) were milled and sintered. They were classified into 4 groups according to glazing and LTD (n=15): control, glazing, LTD, and LTD after glazing. A 3-point flexural test was performed with a universal testing machine. X-ray diffraction (XRD) was used to observe changes in the crystal structures of each group, and field emission scanning electron microscopy was used to observe the sizes of the crystal grains. Two-way analysis of variance was used to evaluate the results of the flexural strength tests, and the Tukey honestly significant difference test was performed for post hoc analysis (α=.05). RESULTS: The flexural strength showed significant differences due to glazing (P<.01). No significant differences were found due to LTD (P>.05). The crystal grain size increased with decreasing flexural strength of the specimens. XRD showed monoclinic phases in the groups subjected to LTD. CONCLUSIONS: Glazing significantly reduced the flexural strength of translucent zirconia. LTD decreased the flexural strength of glazed translucent zirconia, but not to a significant extent.


Assuntos
Temperatura Baixa , Materiais Dentários/química , Zircônio/química , Resistência à Flexão , Técnicas In Vitro , Teste de Materiais , Microscopia Eletrônica de Varredura , Fenômenos Ópticos , Propriedades de Superfície , Difração de Raios X
17.
J Cell Biochem ; 118(5): 1189-1200, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-27764896

RESUMO

Chronic alcohol consumption causes hepatic steatosis, which is characterized by a considerable increase in free fatty acid (FFA) and triglyceride levels. To identify the possible proteins involved in the progression to alcoholic hepatosteatosis, we performed proteomic analysis on livers of mice exposed to alcohol. 2D-based proteomic analysis revealed that EtOH exposure in mice changed the expression of 43 proteins compared with that in mice fed a normal diet (ND). The most notable protein changes were proteins involved in Met metabolism and oxidative stress, most of which were significantly downregulated in alcohol-exposed animals. Although non-alcoholic fatty liver disease (NAFLD) and alcoholic liver disease (ALD) seem to share the same molecular processes, the difference between these conditions is still unclear. To address this question, we explored the features of alcoholic hepatosteatosis that were different compared with those of methionine and choline deficient (MCD) diet-induced mice with nonalcoholic liver damage. Although most of the differentially expressed proteins associated with ALD did not significantly differ from those of NAFLD, nine proteins showed considerably different patterns. Of these, ornithine aminotransferase, vitamin D binding protein, and phosphatidylethanolamine-binding protein were considerably upregulated in ALD mice, compared to that in NAFLD and ND mice. However, other proteins including inorganic pyrophosphatase were differentially regulated in MCD mice; however, they did not differ significantly between the alcoholic model and ND control mice. These results suggested that the identified proteins might be useful candidate markers to differentiate ALD from NAFLD. J. Cell. Biochem. 118: 1189-1200, 2017. © 2016 Wiley Periodicals, Inc.


Assuntos
Biomarcadores/metabolismo , Hepatopatias Alcoólicas/metabolismo , Hepatopatia Gordurosa não Alcoólica/metabolismo , Proteômica/métodos , Animais , Deficiência de Colina/complicações , Modelos Animais de Doenças , Regulação da Expressão Gênica , Hepatopatias Alcoólicas/etiologia , Masculino , Metionina/deficiência , Camundongos , Camundongos Endogâmicos C57BL , Hepatopatia Gordurosa não Alcoólica/etiologia , Estresse Oxidativo
18.
Nanotechnology ; 28(18): 185603, 2017 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-28393764

RESUMO

We present facile synthesis of bright CdS/CdSe/CdS@SiO2 nanoparticles with 72% of quantum yields (QYs) retaining ca 80% of the original QYs. The main innovative point is the utilization of the highly luminescent CdS/CdSe/CdS seed/spherical quantum well/shell (SQW) as silica coating seeds. The significance of inorganic semiconductor shell passivation and structure design of quantum dots (QDs) for obtaining bright QD@SiO2 is demonstrated by applying silica encapsulation via reverse microemulsion method to three kinds of QDs with different structure: CdSe core and 2 nm CdS shell (CdSe/CdS-thin); CdSe core and 6 nm CdS shell (CdSe/CdS-thick); and CdS core, CdSe intermediate shell and 5 nm CdS outer shell (CdS/CdSe/CdS-SQW). Silica encapsulation inevitably results in lower photoluminescence quantum yield (PL QY) than pristine QDs due to formation of surface defects. However, the retaining ratio of pristine QY is different in the three silica coated samples; for example, CdSe/CdS-thin/SiO2 shows the lowest retaining ratio (36%) while the retaining ratio of pristine PL QY in CdSe/CdS-thick/SiO2 and SQW/SiO2 is over 80% and SQW/SiO2 shows the highest resulting PL QY. Thick outermost CdS shell isolates the excitons from the defects at surface, making PL QY relatively insensitive to silica encapsulation. The bright SiO2-coated SQW sample shows robustness against harsh conditions, such as acid etching and thermal annealing. The high luminescence and long-term stability highlights the potential of using the SQW/SiO2 nanoparticles in bio-labeling or display applications.

19.
Phytother Res ; 31(5): 783-791, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28299850

RESUMO

Although Pinus koraiensis leaf (PKL) was reported for its anti-diabetes, anti-obesity and anticancer effects as a folk remedy, the inhibitory effect of PKL on alcoholic fatty liver has never been elucidated yet. This study investigated the molecular mechanisms of PKL on alcoholic fatty liver in HepG2 cells, Sprague Dawley (SD) rats and Imprinting Control Region (ICR) mice. Pinus koraiensis leaf increased phosphorylation of liver kinase B1 (LKB1)/AMP-activated protein kinase signaling, low-density lipoprotein receptor and decreased fatty acid biosynthesis-related proteins such as sterol regulatory element-binding protein 1c, fatty acid synthase, 3-hydroxy-3-methylglutaryl-CoA reductase in HepG2 cells. In SD rats with 25% alcohol-induced fatty liver, PKL suppressed the levels of aspartate aminotransferase and triglyceride and also enhanced the activities of antioxidant enzymes including superoxide dismutase, glutathione peroxidase and glutathione s-transferase compared with untreated control. Furthermore, PKL increased serum alcohol dehydrogenase and serum aldehyde dehydrogenase, but decreased serum alcohol concentration in ICR mice after alcohol administration. Consistently, histochemical analysis revealed that PKL attenuated alcohol-induced fatty liver in SD rats. Overall, these findings suggest that PKL ameliorates alcohol-induced fatty liver via activation of LKB1-AMP-activated protein kinase and modulation of proteins related to lipogenesis synthesis, cholesterol synthesis and fatty acid oxidation. Copyright © 2017 John Wiley & Sons, Ltd.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Etanol/toxicidade , Pinus/química , Extratos Vegetais/farmacologia , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais/efeitos dos fármacos , Quinases Proteína-Quinases Ativadas por AMP , Proteínas Quinases Ativadas por AMP/genética , Animais , Etanol/química , Fígado Gorduroso Alcoólico , Glutationa Transferase/metabolismo , Células Hep G2 , Humanos , Metabolismo dos Lipídeos/efeitos dos fármacos , Lipogênese/efeitos dos fármacos , Lipoproteínas LDL/metabolismo , Fígado/efeitos dos fármacos , Masculino , Camundongos , Fosforilação , Extratos Vegetais/química , Folhas de Planta/metabolismo , Proteínas Serina-Treonina Quinases/genética , Ratos , Ratos Sprague-Dawley , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Triglicerídeos/metabolismo
20.
J Med Syst ; 41(12): 186, 2017 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-29039621

RESUMO

The work of a hospital's medical staff is safety critical and often occurs under severe time constraints. To provide timely and effective cognitive support to medical teams working in such contexts, guidelines in the form of best practice workflows for healthcare have been developed by medical organizations. However, the high cognitive load imposed in such stressful and rapidly changing environments poses significant challenges to the medical staff or team in adhering to these workflows. In collaboration with physicians and nurses from Carle Foundation Hospital, we first studied and modeled medical team's individual responsibilities and interactions in cardiac arrest resuscitation and decomposed their overall task into a set of distinct cognitive tasks that must be specifically supported to achieve successful human-centered system design. We then developed a medical Best Practice Guidance (BPG) system for reducing medical teams' cognitive load, thus fostering real-time adherence to best practices. We evaluated the resulting system with physicians and nurses using a professional patient simulator used for medical training and certification. The evaluation results point to a reduction of cognitive load and enhanced adherence to medical best practices.


Assuntos
Parada Cardíaca/terapia , Equipe de Respostas Rápidas de Hospitais/organização & administração , Sistemas de Informação/organização & administração , Corpo Clínico Hospitalar/organização & administração , Recursos Humanos de Enfermagem Hospitalar/organização & administração , Estresse Ocupacional/psicologia , Meio Ambiente , Humanos , Corpo Clínico Hospitalar/psicologia , Monitorização Fisiológica , Recursos Humanos de Enfermagem Hospitalar/psicologia , Equipe de Assistência ao Paciente/organização & administração , Guias de Prática Clínica como Assunto , Treinamento por Simulação , Fatores de Tempo , Fluxo de Trabalho
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