Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 100
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Small ; 20(7): e2305873, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37803396

RESUMO

N-doped carbon (NC)-encapsulated transition metal (TM) nanocomposites are considered as alternatives to Pt-based hydrogen evolution reaction (HER) electrocatalysts; however, their poor electron transfer and mass diffusion capability at high current densities hinder their practical application. Herein, an oriented coupling strategy for the in situ grafting of ultrafine Co nanoparticle-embedded hollow porous C polyhedra onto Si nanowires (Co/NC-HP@Si-NWs) is proposed to address this concern. Experimental investigations reveal that the intimate coupling between the Si-NW and Co/NC nanocage forms a multithreaded conductive network, lowering the energy barrier for internal electron transfer. When functionalized as an HER electrocatalyst in 0.5 m H2 SO4 , Co/NC-HP@Si-NWs deliver overpotentials as low as 57 and 440 mV at 10 and 500 mA cm-2 , respectively, which are much better than those of the pristine Co/NC-HP. Moreover, Co/NC-HP@Si-NWs show an outstanding cycle durability of 24 h at 10 and 500 mA cm-2 . The findings of this study are expected to inspire revolutionary work on the development of Si-mediated TM-based electrocatalysts for the HER.

2.
Acta Neuropathol ; 147(1): 65, 2024 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-38557897

RESUMO

Human microglia are critically involved in Alzheimer's disease (AD) progression, as shown by genetic and molecular studies. However, their role in tau pathology progression in human brain has not been well described. Here, we characterized 32 human donors along progression of AD pathology, both in time-from early to late pathology-and in space-from entorhinal cortex (EC), inferior temporal gyrus (ITG), prefrontal cortex (PFC) to visual cortex (V2 and V1)-with biochemistry, immunohistochemistry, and single nuclei-RNA-sequencing, profiling a total of 337,512 brain myeloid cells, including microglia. While the majority of microglia are similar across brain regions, we identified a specific subset unique to EC which may contribute to the early tau pathology present in this region. We calculated conversion of microglia subtypes to diseased states and compared conversion patterns to those from AD animal models. Targeting genes implicated in this conversion, or their upstream/downstream pathways, could halt gene programs initiated by early tau progression. We used expression patterns of early tau progression to identify genes whose expression is reversed along spreading of spatial tau pathology (EC > ITG > PFC > V2 > V1) and identified their potential involvement in microglia subtype conversion to a diseased state. This study provides a data resource that builds on our knowledge of myeloid cell contribution to AD by defining the heterogeneity of microglia and brain macrophages during both temporal and regional pathology aspects of AD progression at an unprecedented resolution.


Assuntos
Doença de Alzheimer , Animais , Humanos , Doença de Alzheimer/patologia , Proteínas tau/genética , Proteínas tau/metabolismo , Transcriptoma , Encéfalo/patologia , Células Mieloides/patologia , Microglia/patologia , Peptídeos beta-Amiloides/metabolismo
3.
Pediatr Res ; 2024 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-38871802

RESUMO

BACKGROUND: Neuroblastoma (NB) is a common extracranial solid malignancy in children. The N7-methylguanosine (m7G) modification gene METTL1/WDR4 polymorphisms may serve as promising molecular markers for identifying populations susceptible to NB. METHODS: TaqMan probes was usded to genotype METTL1/WDR4 single nucleotide polymorphisms (SNPs) in 898 NB patients and 1734 healthy controls. A logistic regression model was utilized to calculate the odds ratio (OR) and 95% confidence interval (CI), evaluating the association between genotype polymorphisms and NB susceptibility. The analysis was also stratified by age, sex, tumor origin site, and clinical stage. RESULTS: Individual polymorphism of the METTL1/WDR4 gene investigated in this study did not show significant associations with NB susceptibility. However, combined genotype analysis revealed that carrying all 5 WDR4 protective genotypes was associated with a significantly lower NB risk compared to having 0-4 protective genotypes (AOR = 0.82, 95% CI = 0.69-0.96, P = 0.014). Further stratified analyses revealed that carrying 1-3 METTL1 risk genotypes, the WDR4 rs2156316 CG/GG genotype, the WDR4 rs2248490 CG/GG genotype, and having all five WDR4 protective genotypes were all significantly correlated with NB susceptibility in distinct subpopulations. CONCLUSIONS: In conclusion, our findings suggest significant associations between m7G modification gene METTL1/WDR4 SNPs and NB susceptibility in specific populations. IMPACT: Genetic variation in m7G modification gene is associated with susceptibility to NB. Single nucleotide polymorphisms in METTL1/WDR4 are associated with susceptibility to NB. Single nucleotide polymorphisms of METTL1/WDR4 can be used as a biomarker for screening NB susceptible populations.

4.
Circ Res ; 131(5): 456-472, 2022 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-35920168

RESUMO

BACKGROUND: Ischemic heart disease is a major global public health challenge, and its functional outcomes remain poor. Lysine crotonylation (Kcr) was recently identified as a post-translational histone modification that robustly indicates active promoters. However, the role of Kcr in myocardial injury is unknown. In this study, we aimed to clarify the pathophysiological significance of Kcr in cardiac injury and explore the underlying mechanism. METHODS: We investigated the dynamic change of both the Kcr sites and protein level in left ventricular tissues at 2 time points following sham or cardiac ischemia-reperfusion injury, followed by liquid chromatography-coupled tandem mass tag mass spectrometry. After validation of the enriched protein Kcr by immunoprecipitation and Western blot, the function and mechanism of specific Kcr sites were further investigated in vitro and in vivo by gain- or loss-of-function mutations targeting Kcr sites of selected proteins. RESULTS: We found that cardiac ischemia-reperfusion injury triggers preferential Kcr of proteins required for cardiomyocyte contractility, including mitochondrial and cytoskeleton proteins, which occurs largely independently of protein-level changes in the same proteins. Those exhibiting Kcr changes were associated not only with disruption of cardiomyocyte mitochondrial, sarcomere architecture, and gap junction but also with cardiomyocyte autophagy and apoptosis. Modulating site-specific Kcr of selected mitochondrial protein IDH3a (isocitrate dehydrogenase 3 [NAD+] alpha) at K199 and cytoskeletal protein TPM1 (tropomyosin alpha-1 chain) at K28/29 or enhancing general Kcr via sodium crotonate provision not only protects cardiomyocyte from apoptosis by inhibiting BNIP3 (Bcl-2 adenovirus E18 19-kDa-interacting protein 3)-mediated mitophagy or cytoskeleton structure rearrangement but also preserves postinjury myocardial function by inhibiting fibrosis and apoptosis. CONCLUSIONS: Our results indicate that Kcr modulation is a key response of cardiomyocytes to ischemia-reperfusion injury and may represent a novel therapeutic target in the context of ischemic heart disease.


Assuntos
Isquemia Miocárdica , Traumatismo por Reperfusão , Humanos , Lisina/metabolismo , Isquemia Miocárdica/metabolismo , Miocárdio/metabolismo , Miócitos Cardíacos/metabolismo
5.
J Formos Med Assoc ; 123(1): 98-105, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37365098

RESUMO

BACKGROUND/PURPOSE: Encapsulating peritoneal sclerosis (EPS) is a rare and potential lethal complication of peritoneal dialysis characterized by bowel obstruction. Surgical enterolysis is the only curative therapy. Currently, there are no tools for predicting postsurgical prognosis. This study aimed to identify a computed tomography (CT) scoring system that could predict mortality after surgery in patients with severe EPS. METHODS: This retrospective study enrolled patients with severe EPS who underwent surgical enterolysis in a tertiary referral medical center. The association of CT score with surgical outcomes including mortality, blood loss, and bowel perforation was analyzed. RESULTS: Thirty-four patients who underwent 37 procedures were recruited and divided into a survivor and non-survivor group. The survivor group had higher body mass indices (BMIs, 18.1 vs. 16.7 kg/m2, p = 0.035) and lower CT scores (11 vs. 17, p < 0.001) than the non-survivor group. The receiver operating characteristic curve revealed that a CT score of ≥15 could be considered a cutoff point to predict surgical mortality, with an area under the curve of 0.93, sensitivity of 88.9%, and specificity of 82.1%. Compared with the group with CT scores of <15, the group with CT scores of ≥15 had a lower BMI (19.7 vs. 16.2 kg/m2, p = 0.004), higher mortality (4.2% vs. 61.5%, p < 0.001), greater blood loss (50 vs. 400 mL, p = 0.007), and higher incidence of bowel perforation (12.5% vs. 61.5%, p = 0.006). CONCLUSION: The CT scoring system could be useful in predicting surgical risk in patients with severe EPS receiving enterolysis.


Assuntos
Perfuração Intestinal , Fibrose Peritoneal , Humanos , Fibrose Peritoneal/diagnóstico por imagem , Fibrose Peritoneal/etiologia , Fibrose Peritoneal/cirurgia , Estudos Retrospectivos , Perfuração Intestinal/diagnóstico por imagem , Perfuração Intestinal/etiologia , Perfuração Intestinal/cirurgia , Tomografia Computadorizada por Raios X , Resultado do Tratamento , Esclerose/complicações
6.
Nano Lett ; 23(20): 9515-9521, 2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37830516

RESUMO

Two-dimensional (2D) van der Waals single crystals with long-range magnetic order are the precondition and urgent task for developing a 2D spintronics device. In contrast to graphene and transition metal dichalcogenides, the study of 2D single-crystal metal oxides with intrinsic ferromagnetic properties remains a huge challenge. Here, we report a large-size trigonal single-crystal rhodium oxide (SC-Tri-RhO2), with crystal parameters of a = b = 3.074 Å, c = 6.116 Å, and a space group of P3̅m1 (164), exhibiting strong ferromagnetism (FM) at a rather high temperature. Furthermore, theoretical calculations suggest that the ferromagnetism in SC-Tri-RhO2 originates from spin splitting near the Fermi level, and the total magnetic moment is contributed mainly by the Rh atom.

7.
Angew Chem Int Ed Engl ; 62(20): e202218924, 2023 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-36932034

RESUMO

Electrochemical two-electron oxygen reduction reaction (2 e- ORR) to produce hydrogen peroxide (H2 O2 ) is a promising alternative to the energetically intensive anthraquinone process. However, there remain challenges in designing 2 e- ORR catalysts that meet the application criteria. Here, we successfully adopt a microwave-assisted mechanochemical-thermal approach to synthesize hexagonal phase SnO2 (h-SnO2 ) nanoribbons with largely exposed edge structures. In 0.1 M Na2 SO4 electrolyte, the h-SnO2 catalysts achieve the excellent H2 O2 selectivity of 99.99 %. Moreover, when employed as the catalyst in flow cell devices, they exhibit a high yield of 3885.26 mmol g-1 h-1 . The enhanced catalytic performance is attributed to the special crystal structure and morphology, resulting in abundantly exposed edge active sites to convert O2 to H2 O2 , which is confirmed by density functional theory calculations.

8.
J Med Virol ; 93(4): 2365-2373, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33314141

RESUMO

Coronavirus disease 2019 (COVID-19) is a newly emerging infectious disease. Our understanding of the clinical characteristics of liver damage and the relationship with disease severity in COVID-19 is still limited. To investigate the serum hepatic enzyme activities in different phenotypes of COVID-19 patients, evaluate their relationship with the illness severity and analyze the correlation of glycyrrhizin treatment and abnormal liver enzyme activities, one hundred and forty-seven patients with COVID-19 were enrolled in a retrospective study that investigated hepatic dysfunction. Liver alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactic dehydrogenase (LDH), Y-glutamyl transferase (GGT), superoxide dismutase (SOD), and alkaline phosphatase (ALP) were analyzed in these patients. Patients with diammonium glycyrrhizinate (DG) treatment were further investigated. Of the 147 patients, 56 (38.1%) had abnormal ALT activity and 80 (54.4%) had abnormal AST activity. The peak of abnormal hepatic enzyme activities occurred at 3 to 6 days after on admission. Serum AST and LDH levels were elevated, while the SOD level was decreased in severe and critical patients, compared with mild cases. DG treatment may alleviate the abnormal liver enzyme activities in non-critical COVID-19 patients. Abnormal liver functions may be observed in patients with COVID-19, and were associated with SARS-CoV-2-induced acute liver damage. Glycyrrhizin treatment may be an effective therapeutic approach for the outcome of abnormal hepatic enzyme activities in severe COVID-19 cases. Serum hepatic enzyme tests may reflect the illness severity and should be monitored.


Assuntos
COVID-19/enzimologia , Fígado/enzimologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Alanina Transaminase/sangue , Fosfatase Alcalina/sangue , Aspartato Aminotransferases/sangue , COVID-19/sangue , COVID-19/metabolismo , Feminino , Humanos , Fígado/metabolismo , Testes de Função Hepática , Masculino , Pessoa de Meia-Idade , Fenótipo , Estudos Retrospectivos , SARS-CoV-2 , Índice de Gravidade de Doença , Superóxido Dismutase/sangue , Adulto Jovem
9.
Angew Chem Int Ed Engl ; 60(31): 16970-16973, 2021 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-34080278

RESUMO

Manipulation of long-lived triplet excitons in organic molecules is key to applications including next-generation optoelectronics, background-free bioimaging, information encryption, and photodynamic therapy. However, for organic room-temperature phosphorescence (RTP), which stems from triplet excitons, it is still difficult to simultaneously achieve efficiency and lifetime enhancement on account of weak spin-orbit coupling and rapid nonradiative transitions, especially in the red and near-infrared region. Herein, we report that a series of fluorescent naphthalimides-which did not originally show observable phosphorescence in solution, as aggregates, in polymer films, or in any other tested host material, including heavy-atom matrices at cryogenic temperatures-can now efficiently produce ultralong RTP (ϕ=0.17, τ=243 ms) in phthalimide hosts. Notably, red RTP (λRTP =628 nm) is realized at a molar ratio of less than 10 parts per billion, demonstrating an unprecedentedly low guest-to-host ratio where efficient RTP can take place in molecular solids.

10.
Addict Biol ; 25(4): e12793, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-31339209

RESUMO

Postretrieval extinction procedures are effective nonpharmacological interventions for disrupting drug-associated memories. Nonetheless, the conditioned stimulus (CS) memory retrieval-extinction procedure is ineffective in inhibiting drug craving and relapse after prolonged withdrawal, which significantly undermines its therapeutic potential. In the present study, we showed that, unlike the CS memory retrieval-extinction procedure, noncontingent heroin injections (unconditioned stimulus [UCS]) 1 hour before the extinction sessions decreased the heroin-priming-induced reinstatement, renewal, and spontaneous recovery of heroin seeking after 28 days of withdrawal (ie, remote heroin-associated memories) in rats. The UCS retrieval manipulation induced reactivation of the basolateral amygdala (BLA) after prolonged withdrawal, and this reactivation was absent with the CS retrieval manipulation. Chemogenetic inactivation of the BLA abolished the inhibitory effect of the UCS memory retrieval-extinction procedure on heroin-priming-induced reinstatement after prolonged withdrawal. Furthermore, the combination of chemogenetic reactivation of BLA and CS retrieval-extinction procedure resembled the inhibitory effect of UCS retrieval-extinction procedure on heroin seeking after prolonged withdrawal. We also observed that the inhibitory effect of the UCS retrieval-extinction procedure is mediated by regulation of AMPA receptor endocytosis in the BLA. Our results demonstrate critical engagement of the BLA in reconsolidation updating of heroin-associated memory after prolonged withdrawal, extending our knowledge of the boundary conditions of the reconsolidation of drug-associated memories.


Assuntos
Complexo Nuclear Basolateral da Amígdala/metabolismo , Comportamento de Procura de Droga/fisiologia , Extinção Psicológica/fisiologia , Dependência de Heroína/metabolismo , Heroína/farmacologia , Consolidação da Memória/fisiologia , Entorpecentes/farmacologia , Animais , Complexo Nuclear Basolateral da Amígdala/fisiologia , Núcleo Central da Amígdala/metabolismo , Núcleo Central da Amígdala/fisiologia , Endocitose , Dependência de Heroína/fisiopatologia , Masculino , Ratos , Receptores de AMPA/metabolismo , Fatores de Tempo
11.
Brain ; 141(8): 2457-2474, 2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-29945247

RESUMO

Down syndrome, caused by trisomy of chromosome 21, is the single most common risk factor for early-onset Alzheimer's disease. Worldwide approximately 6 million people have Down syndrome, and all these individuals will develop the hallmark amyloid plaques and neurofibrillary tangles of Alzheimer's disease by the age of 40 and the vast majority will go on to develop dementia. Triplication of APP, a gene on chromosome 21, is sufficient to cause early-onset Alzheimer's disease in the absence of Down syndrome. However, whether triplication of other chromosome 21 genes influences disease pathogenesis in the context of Down syndrome is unclear. Here we show, in a mouse model, that triplication of chromosome 21 genes other than APP increases amyloid-ß aggregation, deposition of amyloid-ß plaques and worsens associated cognitive deficits. This indicates that triplication of chromosome 21 genes other than APP is likely to have an important role to play in Alzheimer's disease pathogenesis in individuals who have Down syndrome. We go on to show that the effect of trisomy of chromosome 21 on amyloid-ß aggregation correlates with an unexpected shift in soluble amyloid-ß 40/42 ratio. This alteration in amyloid-ß isoform ratio occurs independently of a change in the carboxypeptidase activity of the γ-secretase complex, which cleaves the peptide from APP, or the rate of extracellular clearance of amyloid-ß. These new mechanistic insights into the role of triplication of genes on chromosome 21, other than APP, in the development of Alzheimer's disease in individuals who have Down syndrome may have implications for the treatment of this common cause of neurodegeneration.


Assuntos
Síndrome de Down/genética , Síndrome de Down/patologia , Placa Amiloide/genética , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/fisiologia , Animais , Encéfalo/patologia , Modelos Animais de Doenças , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Emaranhados Neurofibrilares/patologia , Placa Amiloide/patologia , Trissomia
12.
J Nanosci Nanotechnol ; 18(7): 4495-4500, 2018 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-29442624

RESUMO

In this paper, gold nanoparticles were obtained by gamma-ray irradiation in aqueous solution containing HAuCl4 as the precursor. The reaction generated particles that contained no foreign stabilizer. The additive-free gold nanoparticles were employed to modify glassy carbon electrode for the detection of dopamine in phosphate buffer solution. Electrochemical properties of the modified electrode were examined by cyclic voltammertry and electrochemical impedance spectroscopy. Linear analytical curves were obtained in the range from 2 to 120 µM for dopamine by differential pulse voltammetry, with the detection limit of 0.13 µM (signal-to-noise ratio of 3). The relatively simple synthetic method of the gold nanoparticles and excellent electrochemical performance with high reproducibility and stability of the detection were promising for further applications.


Assuntos
Dopamina/análise , Ouro , Nanopartículas Metálicas , Carbono , Técnicas Eletroquímicas , Eletrodos , Raios gama , Limite de Detecção , Reprodutibilidade dos Testes
13.
Proc Natl Acad Sci U S A ; 112(8): E881-90, 2015 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-25675483

RESUMO

Cerebral amyloid angiopathy (CAA) is characterized by deposition of amyloid ß peptide (Aß) within walls of cerebral arteries and is an important cause of intracerebral hemorrhage, ischemic stroke, and cognitive dysfunction in elderly patients with and without Alzheimer's Disease (AD). NADPH oxidase-derived oxidative stress plays a key role in soluble Aß-induced vessel dysfunction, but the mechanisms by which insoluble Aß in the form of CAA causes cerebrovascular (CV) dysfunction are not clear. Here, we demonstrate evidence that reactive oxygen species (ROS) and, in particular, NADPH oxidase-derived ROS are a key mediator of CAA-induced CV deficits. First, the NADPH oxidase inhibitor, apocynin, and the nonspecific ROS scavenger, tempol, are shown to reduce oxidative stress and improve CV reactivity in aged Tg2576 mice. Second, the observed improvement in CV function is attributed both to a reduction in CAA formation and a decrease in CAA-induced vasomotor impairment. Third, anti-ROS therapy attenuates CAA-related microhemorrhage. A potential mechanism by which ROS contribute to CAA pathogenesis is also identified because apocynin substantially reduces expression levels of ApoE-a factor known to promote CAA formation. In total, these data indicate that ROS are a key contributor to CAA formation, CAA-induced vessel dysfunction, and CAA-related microhemorrhage. Thus, ROS and, in particular, NADPH oxidase-derived ROS are a promising therapeutic target for patients with CAA and AD.


Assuntos
Envelhecimento/patologia , Angiopatia Amiloide Cerebral/patologia , Angiopatia Amiloide Cerebral/fisiopatologia , Hemorragia Cerebral/patologia , Hemorragia Cerebral/fisiopatologia , Espécies Reativas de Oxigênio/metabolismo , Sistema Vasomotor/fisiopatologia , Acetofenonas/farmacologia , Animais , Apolipoproteínas E/metabolismo , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Astrócitos/patologia , Encéfalo/efeitos dos fármacos , Encéfalo/patologia , Encéfalo/fisiopatologia , Angiopatia Amiloide Cerebral/complicações , Artérias Cerebrais/patologia , Artérias Cerebrais/fisiopatologia , Hemorragia Cerebral/complicações , Cricetinae , Óxidos N-Cíclicos/farmacologia , Humanos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Microglia/efeitos dos fármacos , Microglia/metabolismo , Microglia/patologia , Músculo Liso Vascular/patologia , Miócitos de Músculo Liso/efeitos dos fármacos , Miócitos de Músculo Liso/metabolismo , Miócitos de Músculo Liso/patologia , Estresse Oxidativo/efeitos dos fármacos , Marcadores de Spin , Sistema Vasomotor/efeitos dos fármacos , Sistema Vasomotor/patologia
14.
Angew Chem Int Ed Engl ; 57(49): 16046-16050, 2018 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-30334606

RESUMO

Room-temperature phosphorescence (RTP)-based sensors have distinctive advantages over the fluorescence counterparts, such as larger Stokes shifts and longer lifetimes. Unfortunately, almost all RTP sensors are operated on quenching-based mechanisms given the sensitive nature of the emissive triplet state. Here we report a type of thioether RTP molecules that shows RTP "turn-on" when volatile acid vapors such as HCl are in contact. To elucidate the underlying mechanism, model thioethers containing different donor/acceptor combinations are investigated via fluorescence spectroscopy and theoretical calculations aided by molecular coordinates obtained from single-crystal X-ray diffraction. It is revealed that a charge-transfer character in the phosphorescence state is crucial. The "turn-on" design concept may significantly broaden the sensing application scope for organic RTP molecules.

15.
Curr Opin Lipidol ; 28(1): 60-67, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27922847

RESUMO

PURPOSE OF REVIEW: APOE4 genotype is the strongest genetic risk factor for Alzheimer's disease. Prevailing evidence suggests that amyloid ß plays a critical role in Alzheimer's disease. The objective of this article is to review the recent findings about the metabolism of apolipoprotein E (ApoE) and amyloid ß and other possible mechanisms by which ApoE contributes to the pathogenesis of Alzheimer's disease. RECENT FINDINGS: ApoE isoforms have differential effects on amyloid ß metabolism. Recent studies demonstrated that ApoE-interacting proteins, such as ATP-binding cassette A1 (ABCA1) and LDL receptor, may be promising therapeutic targets for Alzheimer's disease treatment. Activation of liver X receptor and retinoid X receptor pathway induces ABCA1 and other genes, leading to amyloid ß clearance. Inhibition of the negative regulators of ABCA1, such as microRNA-33, also induces ABCA1 and decreases the levels of ApoE and amyloid ß. In addition, genetic inactivation of an E3 ubiquitin ligase, myosin regulatory light chain interacting protein, increases LDL receptor levels and inhibits amyloid accumulation. Although amyloid ß-dependent pathways have been extensively investigated, there have been several recent studies linking ApoE with vascular function, neuroinflammation, metabolism, synaptic plasticity, and transcriptional regulation. For example, ApoE was identified as a ligand for a microglial receptor, TREM2, and studies suggested that ApoE may affect the TREM2-mediated microglial phagocytosis. SUMMARY: Emerging data suggest that ApoE affects several amyloid ß-independent pathways. These underexplored pathways may provide new insights into Alzheimer's disease pathogenesis. However, it will be important to determine to what extent each mechanism contributes to the pathogenesis of Alzheimer's disease.


Assuntos
Doença de Alzheimer/metabolismo , Apolipoproteínas E/metabolismo , Encéfalo/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/fisiopatologia , Animais , Encéfalo/fisiopatologia , Regulação da Expressão Gênica , Humanos , Plasticidade Neuronal , Transcrição Gênica
16.
J Biol Chem ; 291(53): 27204-27218, 2016 12 30.
Artigo em Inglês | MEDLINE | ID: mdl-27793990

RESUMO

The risk of Alzheimer's disease (AD) is highly dependent on apolipoprotein-E (apoE) genotype. The reasons for apoE isoform-selective risk are uncertain; however, both the amounts and structure of human apoE isoforms have been hypothesized to lead to amyloidosis increasing the risk for AD. To address the hypothesis that amounts of apoE isoforms are different in the human CNS, we developed a novel isoform-specific method to accurately quantify apoE isoforms in clinically relevant samples. The method utilizes an antibody-free enrichment step and isotope-labeled physiologically relevant lipoprotein particle standards produced by immortalized astrocytes. We applied this method to a cohort of well characterized clinical samples and observed the following findings. The apoE isoform amounts are not different in cerebrospinal fluid (CSF) from young normal controls, suggesting that the amount of apoE isoforms is not the reason for risk of amyloidosis prior to the onset of advanced age. We did, however, observe an age-related increase in both apoE isoforms. In contrast to normal aging, the presence of amyloid increased apoE3, whereas apoE4 was unchanged or decreased. Importantly, for heterozygotes, the apoE4/apoE3 isoform ratio was increased in the CNS, although the reverse was true in the periphery. Finally, CSF apoE levels, but not plasma apoE levels, correlated with CSF ß-amyloid levels. Collectively, these findings support the hypothesis that CNS and peripheral apoE are separate pools and differentially regulated. Furthermore, these results suggest that apoE mechanisms for the risk of amyloidosis and AD are related to an interaction between apoE, aging, and the amount of amyloid burden.


Assuntos
Amiloidose/sangue , Amiloidose/líquido cefalorraquidiano , Apolipoproteína E3/análise , Apolipoproteína E4/análise , Biomarcadores/análise , Encéfalo/metabolismo , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/sangue , Doença de Alzheimer/líquido cefalorraquidiano , Doença de Alzheimer/diagnóstico , Sequência de Aminoácidos , Amiloidose/diagnóstico , Astrócitos/citologia , Astrócitos/metabolismo , Estudos de Casos e Controles , Células Cultivadas , Demência/sangue , Demência/líquido cefalorraquidiano , Demência/diagnóstico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
17.
BMC Pulm Med ; 17(1): 105, 2017 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-28747201

RESUMO

BACKGROUND: Positive-pressure mechanical ventilation is essential in assisting patients with respiratory failure in the intensive care unit and facilitating oxygenation in the operating room. However, it was also recognized as a primary factor leading to hospital-acquired pulmonary dysfunction, in which pulmonary oxidative stress and lung inflammation had been known to play important roles. Cu/Zn superoxide dismutase (SOD) is an important antioxidant, and possesses anti-inflammatory capacity. In this study, we aimed to study the efficacy of Cu/Zn SOD, administered intravenously during high tidal volume (HTV) ventilation, to prevent impairment of lung function. METHODS: Thirty-eight male Sprague-Dawley rats were divided into 3 groups: 5 h ventilation with (A) low tidal volume (LTV; 8 mL/kg; n = 10), (B) high tidal volume (HTV; 18 mL/kg; n = 14), or (C) HTV and intravenous treatment of Cu/Zn SOD at a dose of 1000 U/kg/h (HTV + SOD; n = 14). Lung function was evaluated both at baseline and after 5-h ventilation. Lung injury was assessed by histological examination, lung water and protein contents in the bronchoalveolar lavage fluid (BALF). Pulmonary oxidative stress was examined by concentrations of methylguanidine (MG) and malondialdehyde (MDA) in BALF, and antioxidative activity by protein expression of glutathione peroxidase-1 (GPx-1) in the lung. Severity of lung inflammation was evaluated by white blood cell and differential count in BALF, and protein expression of inducible nitric oxide synthase (iNOS), intercellular adhesion molecule-1 (ICAM-1), tumor necrosis factor-α (TNF-α), matrix metalloproteinase-9 (MMP-9), and mRNA expression of nuclear factor-κB (NF-κB) in the lung. We also examined protein expression of surfactant protein (SP)-A and D and we measured hourly changes in serum nitric oxide (NO) level. RESULTS: Five hours of LTV ventilation did not induce a major change in lung function, whereas 5 h of HTV ventilation induced apparent combined restrictive and obstructive lung disorder, together with increased pulmonary oxidative stress, decreased anti-oxidative activity and increased lung inflammation (P < 0.05). HTV ventilation also decreased SP-A and SP-D expression and suppressed serum NO level during the time course of ventilation. Cu/Zn SOD administered intravenously during HTV ventilation effectively reversed associated pulmonary oxidative stress and lung inflammation (P < 0.05); moreover, it preserved SP-A and SP-D expressions in the lung and increased serum nitric oxide (NO) level, enhancing vascular NO bioavailability. CONCLUSIONS: HTV ventilation can induce combined restrictive and obstructive lung disorders. Intravenous administration of Cu/Zn SOD during HTV ventilation can prevent lung function impairment and lung injury via reducing pulmonary oxidative stress and lung inflammation, preserving pulmonary surfactant expression, and enhancing vascular NO bioavailability.


Assuntos
Sequestradores de Radicais Livres/farmacologia , Pulmão/efeitos dos fármacos , Respiração com Pressão Positiva/efeitos adversos , Superóxido Dismutase/farmacologia , Administração Intravenosa , Animais , Líquido da Lavagem Broncoalveolar/química , Líquido da Lavagem Broncoalveolar/citologia , Glutationa Peroxidase/efeitos dos fármacos , Glutationa Peroxidase/metabolismo , Molécula 1 de Adesão Intercelular/efeitos dos fármacos , Molécula 1 de Adesão Intercelular/metabolismo , Antígenos Comuns de Leucócito , Pulmão/metabolismo , Pulmão/fisiopatologia , Masculino , Metaloproteinase 9 da Matriz/efeitos dos fármacos , Metaloproteinase 9 da Matriz/metabolismo , NF-kappa B/efeitos dos fármacos , NF-kappa B/genética , Óxido Nítrico Sintase Tipo II/efeitos dos fármacos , Óxido Nítrico Sintase Tipo II/metabolismo , Proteína A Associada a Surfactante Pulmonar/efeitos dos fármacos , Proteína A Associada a Surfactante Pulmonar/metabolismo , Proteína D Associada a Surfactante Pulmonar/efeitos dos fármacos , Proteína D Associada a Surfactante Pulmonar/metabolismo , RNA Mensageiro/efeitos dos fármacos , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Volume de Ventilação Pulmonar , Fator de Necrose Tumoral alfa/efeitos dos fármacos , Fator de Necrose Tumoral alfa/metabolismo , Lesão Pulmonar Induzida por Ventilação Mecânica , Glutationa Peroxidase GPX1
18.
Nanotechnology ; 27(24): 245709, 2016 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-27171125

RESUMO

Great progress has been made in fluorescence-based detection utilizing solid state enhanced substrates in recent years. However, it is still difficult to achieve reliable substrates with tunable enhancement factors. The present work shows liquid fluorescence enhanced substrates consisting of suspensions of Fe3O4 nanoparticles (NPs), which can assemble 3D photonic crystal under the external magnetic field. The photonic bandgap induced by the equilibrium of attractive magnetic force and repulsive electrostatic force between adjacent Fe3O4 NPs is utilized to enhance fluorescence intensity of dye molecules (including R6G, RB, Cy5, DMTPS-DCV) in a reversible and controllable manner. The results show that a maximum of 12.3-fold fluorescence enhancement is realized in the 3D Fe3O4 NP substrates without the utilization of metal particles for PCs/DMTPS-DCV (1.0 × 10(-7) M, water fraction (f w) = 90%).

19.
J Neurosci ; 34(21): 7281-92, 2014 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-24849360

RESUMO

Apolipoprotein E (apoE) is the strongest known genetic risk factor for late onset Alzheimer's disease (AD). It influences amyloid-ß (Aß) clearance and aggregation, which likely contributes in large part to its role in AD pathogenesis. We recently found that HJ6.3, a monoclonal antibody against apoE, significantly reduced Aß plaque load when given to APPswe/PS1ΔE9 (APP/PS1) mice starting before the onset of plaque deposition. To determine whether the anti-apoE antibody HJ6.3 affects Aß plaques, neuronal network function, and behavior in APP/PS1 mice after plaque onset, we administered HJ6.3 (10 mg/kg/week) or PBS intraperitoneally to 7-month-old APP/PS1 mice for 21 weeks. HJ6.3 mildly improved spatial learning performance in the water maze, restored resting-state functional connectivity, and modestly reduced brain Aß plaque load. There was no effect of HJ6.3 on total plasma cholesterol or cerebral amyloid angiopathy. To investigate the underlying mechanisms of anti-apoE immunotherapy, HJ6.3 was applied to the brain cortical surface and amyloid deposition was followed over 2 weeks using in vivo imaging. Acute exposure to HJ6.3 affected the course of amyloid deposition in that it prevented the formation of new amyloid deposits, limited their growth, and was associated with occasional clearance of plaques, a process likely associated with direct binding to amyloid aggregates. Topical application of HJ6.3 for only 14 d also decreased the density of amyloid plaques assessed postmortem. Collectively, these studies suggest that anti-apoE antibodies have therapeutic potential when given before or after the onset of Aß pathology.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Anticorpos/uso terapêutico , Apolipoproteínas E/imunologia , Encéfalo/metabolismo , Doença de Alzheimer/sangue , Doença de Alzheimer/genética , Peptídeos beta-Amiloides/efeitos dos fármacos , Precursor de Proteína beta-Amiloide/genética , Amiloidose/tratamento farmacológico , Amiloidose/metabolismo , Amiloidose/patologia , Animais , Encéfalo/efeitos dos fármacos , Colesterol/sangue , Modelos Animais de Doenças , Feminino , Hemorragia/tratamento farmacológico , Hemorragia/etiologia , Coxeadura Animal/tratamento farmacológico , Coxeadura Animal/etiologia , Aprendizagem em Labirinto/efeitos dos fármacos , Aprendizagem em Labirinto/fisiologia , Camundongos , Camundongos Transgênicos , Mutação/genética , Presenilina-1/genética
20.
Stroke ; 46(6): 1633-1640, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25944329

RESUMO

BACKGROUND AND PURPOSE: Cerebral amyloid angiopathy (CAA) is a common cause of recurrent intracerebral hemorrhage in the elderly. Previous studies have shown that CAA induces inflammation and expression of matrix metalloproteinase-2 and matrix metalloproteinase-9 (gelatinases) in amyloid-laden vessels. Here, we inhibited both using minocycline in CAA mouse models to determine whether spontaneous intracerebral hemorrhage could be reduced. METHODS: Tg2576 (n=16) and 5xFAD/ApoE4 knockin mice (n=16), aged 17 and 12 months, respectively, were treated with minocycline (50 mg/kg, IP) or saline every other day for 2 months. Brains were extracted and stained with X-34 (to quantify amyloid), Perls' blue (to quantify hemorrhage), and immunostained to examined ß-amyloid peptide load, gliosis (glial fibrillary acidic protein [GFAP], Iba-1), and vascular markers of blood-brain barrier integrity (zonula occludins-1 [ZO-1] and collagen IV). Brain extracts were used to quantify mRNA for a variety of inflammatory genes. RESULTS: Minocycline treatment significantly reduced hemorrhage frequency in the brains of Tg2576 and 5xFAD/ApoE4 mice relative to the saline-treated mice, without affecting CAA load. Gliosis (GFAP and Iba-1 immunostaining), gelatinase activity, and expression of a variety of inflammatory genes (matrix metalloproteinase-9, NOX4, CD45, S-100b, and Iba-1) were also significantly reduced. Higher levels of microvascular tight junction and basal lamina proteins were found in the brains of minocycline-treated Tg2576 mice relative to saline-treated controls. CONCLUSIONS: Minocycline reduced gliosis, inflammatory gene expression, gelatinase activity, and spontaneous hemorrhage in 2 different mouse models of CAA, supporting the importance of matrix metalloproteinase-related and inflammatory pathways in intracerebral hemorrhage pathogenesis. As a Food and Drug Administration-approved drug, minocycline might be considered for clinical trials to test efficacy in preventing CAA-related intracerebral hemorrhage.


Assuntos
Antibacterianos/farmacologia , Angiopatia Amiloide Cerebral/tratamento farmacológico , Hemorragia Cerebral/prevenção & controle , Minociclina/farmacologia , Animais , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Angiopatia Amiloide Cerebral/complicações , Angiopatia Amiloide Cerebral/genética , Angiopatia Amiloide Cerebral/metabolismo , Angiopatia Amiloide Cerebral/patologia , Hemorragia Cerebral/etiologia , Hemorragia Cerebral/genética , Hemorragia Cerebral/metabolismo , Hemorragia Cerebral/patologia , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Regulação da Expressão Gênica/efeitos dos fármacos , Proteína Glial Fibrilar Ácida , Inflamação/tratamento farmacológico , Inflamação/genética , Inflamação/metabolismo , Inflamação/patologia , Antígenos Comuns de Leucócito , Metaloproteinase 9 da Matriz/biossíntese , Camundongos , Camundongos Transgênicos , Proteínas dos Microfilamentos/genética , Proteínas dos Microfilamentos/metabolismo , NADPH Oxidase 4 , NADPH Oxidases/biossíntese , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Subunidade beta da Proteína Ligante de Cálcio S100/biossíntese
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA