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BACKGROUND: Remnant cholesterol (RC) is an important marker for assessing the risk of metabolic syndrome. However, the correlation between RC and hyperuricemia (HUA) remains unclear. This study aimed to explore the correlation between RC and HUA in American adults. METHODS: A total of 9089 participants from the 2013-2020 National Health and Nutrition Examination Survey were investigated. The correlation between RC and the odds of HUA was evaluated using multivariate logistic regression analysis. The nonlinear correlation was described using fitted smoothed curves. The correlation in subgroups was analyzed based on race, gender, alcohol consumption, age, body mass index, waist circumference, diabetes and moderate physical activities. RESULTS: RC was correlated with uric acid (Spearman's correlation coefficient = 0.208 in males and 0.215 in females; all P < 0.001). Multiple logistic regression analysis indicated a positive correlation between RC and the risk of HUA (odds ratio = 1.022 in males and 1.031 in females; all P < 0.001). Subgroup analysis revealed that the correlation was stronger in females, participants aged < 50 years, and those without diabetes. Furthermore, the generalized smooth curve fitting demonstrated a linear correlation between RC and HUA, without threshold or saturation effects. CONCLUSION: Elevated RC significantly and positively correlated with HUA in American adults. This correlation was stronger among females, participants aged < 50 years, and those without diabetes.
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Colesterol , Hiperuricemia , Inquéritos Nutricionais , Ácido Úrico , Humanos , Masculino , Feminino , Hiperuricemia/sangue , Hiperuricemia/epidemiologia , Pessoa de Meia-Idade , Adulto , Colesterol/sangue , Ácido Úrico/sangue , Estados Unidos/epidemiologia , Fatores de Risco , Modelos Logísticos , Idoso , Índice de Massa Corporal , Circunferência da Cintura , Razão de Chances , Triglicerídeos/sangue , Síndrome Metabólica/sangue , Síndrome Metabólica/epidemiologiaRESUMO
INTRODUCTION: Previous studies have demonstrated a correlation between the serum uric acid-to-high-density lipoprotein cholesterol ratio (UHR) and insulin resistance (IR) in individuals with type 2 diabetes mellitus. However, no existing studies have investigated the relationship between IR and UHR in the general population. Therefore, the primary objective of this study was to investigate the correlation between UHR and IR in the general American population. METHODS: A sample of 8,817 participants was selected from the 2013 to 2020 National Health and Nutrition Examination Survey (NHANES). Homeostatic model assessment of insulin resistance (HOMA-IR) was used to assess insulin resistance. Multiple logistic regression, generalized smooth curve fitting, and subgroup analysis were used to assess the association between IR and UHR. RESULTS: Multiple logistic regression analysis indicated a significant correlation between insulin resistance and UHR, with odds ratios (OR) of 1.07 (95% CI = 1.03-1.11) in males and 1.18 (95% CI = 1.13-1.25) in females. A non-linear relationship and saturation effect between IR risk and UHR were observed, characterized by an inverted L-shaped curve and a critical inflection point at 8.82. It was found that the area under the ROC curve (AUC) of UHR was significantly larger (AUC = 0.703 for males and 0.747 for females, all P < 0.01) compared with the use of UA or HDL-C alone. Subgroup analysis showed that this independent association remain consistent regardless of race, age, BMI, diabetes, moderate activities, education level, alcohol drinking, and gender. CONCLUSION: Elevated UHR demonstrates a significant correlation with insulin resistance, so it can be used as a potential indicator of insulin resistance within the American population.
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HDL-Colesterol , Resistência à Insulina , Inquéritos Nutricionais , Ácido Úrico , Humanos , Ácido Úrico/sangue , Masculino , Feminino , HDL-Colesterol/sangue , Pessoa de Meia-Idade , Estados Unidos/epidemiologia , Adulto , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/epidemiologia , Estudos Transversais , Biomarcadores/sangue , IdosoRESUMO
BACKGROUND: Liver aging, marked by cellular senescence and low-grade inflammation, heightens susceptibility to chronic liver disease and worsens its prognosis. Insulin-like growth factor 2 (IGF2) has been implicated in numerous aging-related diseases. Nevertheless, its role and underlying molecular mechanisms in liver aging remain largely unexplored. METHODS: The expression of IGF2 was examined in the liver of young (2-4 months), middle-aged (9-12 months), and old (24-26 months) C57BL/6 mice. In vivo, we used transgenic IGF2f/f; Alb-Cre mice and D-galactose-induced aging model to explore the role of IGF2 in liver aging. In vitro, we used specific short hairpin RNA against IGF2 to knock down IGF2 in AML12 cells. D-galactose and hydrogen peroxide treatment were used to induce AML12 cell senescence. RESULTS: We observed a significant reduction of IGF2 levels in the livers of aged mice. Subsequently, we demonstrated that IGF2 deficiency promoted senescence phenotypes and senescence-associated secretory phenotypes (SASPs), both in vitro and in vivo aging models. Moreover, IGF2 deficiency impaired mitochondrial function, reducing mitochondrial respiratory capacity, mitochondrial membrane potential, and nicotinamide adenine dinucleotide (NAD)+/NADH ratio, increasing intracellular and mitochondrial reactive oxygen species levels, and disrupting mitochondrial membrane structure. Additionally, IGF2 deficiency markedly upregulated CCAAT/enhancer-binding protein beta (CEBPB). Notably, inhibiting CEBPB reversed the senescence phenotypes and reduced SASPs induced by IGF2 deficiency. CONCLUSIONS: In summary, our findings strongly suggest that IGF2 deficiency promotes liver aging through mitochondrial dysfunction and upregulated CEBPB signaling. These results provide compelling evidence for considering IGF2 as a potential target for interventions aimed at slowing down the process of liver aging.
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Envelhecimento , Galactose , Animais , Camundongos , Envelhecimento/metabolismo , Galactose/metabolismo , Galactose/farmacologia , Fígado/metabolismo , Camundongos Endogâmicos C57BL , Mitocôndrias/metabolismoRESUMO
BACKGROUND: FLNC (filamin C), a member of the filamin family predominantly expressed in striated muscles, plays a crucial role in bridging the cytoskeleton and ECM (extracellular matrix) in cardiomyocytes, thereby maintaining heart integrity and function. Although genetic variants within the N-terminal ABD (actin-binding domain) of FLNC have been identified in patients with cardiomyopathy, the precise contribution of the actin-binding capability to FLNC's function in mammalian hearts remains poorly understood. METHODS: We conducted in silico analysis of the 3-dimensional structure of mouse FLNC to identify key amino acid residues within the ABD that are essential for FLNC's actin-binding capacity. Subsequently, we performed coimmunoprecipitation and immunofluorescent assays to validate the in silico findings and assess the impact of these mutations on the interactions with other binding partners and the subcellular localization of FLNC. Additionally, we generated and analyzed knock-in mouse models in which the FLNC-actin interaction was completely disrupted by these mutations. RESULTS: Our findings revealed that F93A/L98E mutations completely disrupted FLNC-actin interaction while preserving FLNC's ability to interact with other binding partners ITGB1 (ß1 integrin) and γ-SAG (γ-sarcoglycan), as well as maintaining FLNC subcellular localization. Loss of FLNC-actin interaction in embryonic cardiomyocytes resulted in embryonic lethality and cardiac developmental defects, including ventricular wall malformation and reduced cardiomyocyte proliferation. Moreover, disruption of FLNC-actin interaction in adult cardiomyocytes led to severe dilated cardiomyopathy, enhanced lethality and dysregulation of key cytoskeleton components. CONCLUSIONS: Our data strongly support the crucial role of FLNC as a bridge between actin filaments and ECM through its interactions with actin, ITGB1, γ-SAG, and other associated proteins in cardiomyocytes. Disruption of FLN-actin interaction may result in detachment of actin filaments from the extracellular matrix, ultimately impairing normal cardiac development and function. These findings also provide insights into mechanisms underlying cardiomyopathy associated with genetic variants in FLNC ABD and other regions.
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Actinas , Cardiomiopatias , Camundongos , Animais , Filaminas/genética , Filaminas/metabolismo , Actinas/genética , Actinas/metabolismo , Músculo Esquelético/metabolismo , Cardiomiopatias/genética , Miócitos Cardíacos/metabolismo , Mutação , MamíferosRESUMO
FLNC, encoding filamin C, is one of the most mutated genes in dilated and hypertrophic cardiomyopathy. However, the precise role of filamin C in mammalian heart remains unclear. In this study, we demonstrated Flnc global (FlncgKO) and cardiomyocyte-specific knockout (FlnccKO) mice died in utero from severely ruptured ventricular myocardium, indicating filamin C is required to maintain the structural integrity of myocardium in the mammalian heart. Contrary to the common belief that filamin C acts as an integrin inactivator, we observed attenuated activation of ß1 integrin specifically in the myocardium of FlncgKO mice. Although deleting ß1 integrin from cardiomyocytes did not recapitulate the heart rupture phenotype in Flnc knockout mice, deleting both ß1 integrin and filamin C from cardiomyocytes resulted in much more severe heart ruptures than deleting filamin C alone. Our results demonstrated that filamin C works in concert with ß1 integrin to maintain the structural integrity of myocardium during mammalian heart development.
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Filaminas , Integrina beta1 , Miocárdio , Animais , Camundongos , Cardiomiopatia Hipertrófica , Filaminas/genética , Integrina beta1/genética , Miócitos CardíacosRESUMO
Combining morphological control engineering and diatomic coupling strategies, heteronuclear FeCo bimetals are efficiently intercalated into nitrogen-doped carbon materials with star-like to simultaneously accelerate oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The half-wave potential and kinetic current density of the ORR driven by FeCoNC/SL surpass the commercial Pt/C catalyst. The overpotential of OER is as low as 316 mV (η10 ), and the mass activity is at least 3.2 and 9.4 times that of mononuclear CoNC/SL and FeNC/SL, respectively. The power density and specific capacity of the Zn-air battery with FeCoNC/SL as air cathode are as high as 224.8 mW cm-2 and 803 mAh g-1 , respectively. Morphologically, FeCoNC/SL endows more reactive sites and accelerates the process of oxygen reaction. Density functional theory reveals the active site of the heteronuclear diatomic, and the formation of FeCoN5C configuration can effectively tune the d-band center and electronic structure. The redistribution of electrons provides conditions for fast electron exchange, and the change of the center of the d-band avoids the strong adsorption of intermediate species to simultaneously take into account both ORR and OER and thus achieve high-performance Zn-air batteries.
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Dual-specificity phosphatase 6 (DUSP6) serves a specific and conserved function on the dephosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2). We previously identified Dusp6 as a regenerative repressor during zebrafish heart regeneration, therefore we propose to investigate the role of this repressor in mammalian cardiac repair. Utilizing a rat strain harboring Dusp6 nonsense mutation, rat neutrophil-cardiomyocyte co-culture, bone marrow transplanted rats and neutrophil-specific Dusp6 knockout mice, we find that Dusp6 deficiency improves cardiac outcomes by predominantly attenuating neutrophil-mediated myocardial damage in acute inflammatory phase after myocardial infarction. Mechanistically, Dusp6 is transcriptionally activated by p38-C/EBPß signaling and acts as an effector for maintaining p-p38 activity by down-regulating pERK and p38-targeting phosphatases DUSP1/DUSP16. Our findings provide robust animal models and novel insights for neutrophil-mediated cardiac damage and demonstrate the potential of DUSP6 as a therapeutic target for post-MI cardiac remodeling and other relevant inflammatory diseases.
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Infarto do Miocárdio , Animais , Camundongos , Ratos , Fosfatase 6 de Especificidade Dupla , Camundongos Knockout , Infarto do Miocárdio/genética , Miocárdio , Miócitos Cardíacos , NeutrófilosRESUMO
In the present work, irregular Cu nanoparticle-decorated boron-carbon-nitrogen (Cu-BCN) nanosheets were successfully synthesized. A Cu-BCN dispersion was deposited on a bare glassy carbon electrode (GCE) to prepare an electrochemical sensor (Cu-BCN/GCE) for the detection of chloramphenicol (CAP) in the environment. Cu-BCN was characterized using high-resolution scanning transmission electron microscopy (HRSTEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis, and X-ray photoelectron spectroscopy (XPS). The performance of the Cu-BCN/GCE was studied using electrochemical impedance spectroscopy (EIS), and its advantages were proven by electrode comparison. Differential pulse voltammetry (DPV) was used to optimize the experimental conditions, including the amount of Cu-BCN deposited, enrichment potential, deposition time, and pH of the electrolyte. A linear relationship between the CAP concentration and current response was obtained under the optimized experimental conditions, with a wide linear range and a limit of detection (LOD) of 2.41 nmol/L. Cu-BCN/GCE exhibited high stability, reproducibility, and repeatability. In the presence of various organic and inorganic species, the influence of the Cu-BCN-based sensor on the current response of CAP was less than 5%. Notably, the prepared sensor exhibited excellent performance in real-water samples, with satisfactory recovery.
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Carbono , Nanopartículas , Boro , Carbono/química , Cloranfenicol , Técnicas Eletroquímicas/métodos , Eletrodos , Limite de Detecção , Nitrogênio , Reprodutibilidade dos TestesRESUMO
BACKGROUND: The goal is to assess the prognosis of cytogenetic abnormality, because cytogenetic abnormality is rarely encountered in clinical practice. METHODS: We retrospectively report three cytogenetic abnormality cases with clinical, cytogenetic, and genetic characteristic. RESULTS: All cases occurred within one month of birth and had prominent hepatosplenomegaly, including acute myeloid leukemia (case 1, case 2) and acute leukemia (case 3). Moreover, case 1 appeared as leukemia cutis at birth, case 2 was born with respiratory distress, and both showed hyperleukocytosis. The R-banded karyotype detected cytogenetic abnormality in three cases, case 1 with 46,XY,t(8;12)(q21;p13), case 2 with 47,XX,+21 and case 3 with 46,XY,t(6;X)(q22:p12), respectively. Especially in case 1, reverse transcription-polymerase chain reaction analysis showed MLL-AF10 rearranged. CONCLUSIONS: In our studies, all cases had not received chemotherapy and survived about 1 - 2 months. It suggests that cytogenetic disorders are closely related to disease development and likely result in fatal outcome if untreated. Thus, we proposed that a proper treatment decision is urgently needed in congenital leukemia.
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Leucemia Mieloide Aguda , Proteína de Leucina Linfoide-Mieloide , Aberrações Cromossômicas , Humanos , Recém-Nascido , Cariotipagem , Leucemia Mieloide Aguda/genética , Proteína de Leucina Linfoide-Mieloide/genética , Estudos RetrospectivosRESUMO
BACKGROUND: Due to the strict measures employed to control the spread of SARS-CoV-2, the extent of COVID-19 goes beyond morbidity and mortality and affects individuals' mental health in the long term. OBJECTIVE: This cross-sectional study aimed to investigate the effects of the COVID-19 pandemic on mental health and its contributing factors among older people in Chengmai County, China. METHODS: A web-based survey was administered through WeChat between March and April 2020. Older people (ie, >50 years) from local and foreign community groups completed the survey, which included items on sociodemographic and clinical characteristics, the 7-item Generalized Anxiety Disorder scale (GAD-7), and the 9-item Patient Health Questionnaire (PHQ-9). Independent t tests and a multiple linear regression analysis were used to investigate differences between anxiety and depression and the factors associated with these symptoms across the 2 groups. RESULTS: Overall, 469 responses were received; 119 responses (25.4%) were from male participants and 202 (43.1%) were from those older than 65 years. Of the 469 responses, 245 (52.2%) were from the local community group and 224 (47.8%) from the foreign group. The mean GAD-7 (P=.003) scores were significantly higher in the local group. Anxiety was significantly more present in the local group (61/245, 24.9% compared to 35/224, 15.6% in the foreign group; P=.01). A total of 6 respondents presented severe anxiety and 2 presented severe depression. CONCLUSIONS: This study demonstrated that both community groups of older adults from the Chinese "Hometown of Longevity" presented anxiety or depressive disorders during the first months of the pandemic. Local community groups presented significantly more mental health disorders, which were associated with a history of previous psychological disorders.
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Electrochemical nitrate reduction reaction (NIRR) driven by sustainable energy is not only expected to realize the green production of ammonia under ambient conditions, but also a promising way to purify nitrate wastewater. The ammonia yield rate and Faradaic efficiency of NIRR catalyzed by Pd10Cu/BCN constructed with structural constraints and pre-embedded reducing agent strategies were as high as 102,153 µg h-1 mgcat.-1 and 91.47%, respectively. Pd10Cu/BCN can remove nearly 100% of 50 mg L-1 NO3- without NO2- residue within 10 h, and the realization of this effect does not require the participation of any chloride. Control experiments and DFT calculations explain the efficient operation mechanism of NIRR on Pd10Cu/BCN, where the Pd and CuN4 sites play the role of synergistic catalysis. Compared with the reported literature, Pd10Cu/BCN with good biocompatibility has become an outstanding representative of NIRR catalyst, which provides an alternative way for the green production of ammonia and the purification of nitrate wastewater.
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Amônia , Nitratos , Boro , Carbono , Cobre/química , Nitratos/química , Nitrogênio , Óxidos de Nitrogênio , Paládio/química , Águas ResiduáriasRESUMO
BACKGROUND: Recent study showed that individuals with type 2 diabetes have a high risk of developing colorectal cancer (CRC), in which Receptor for Advanced Glycation End Products (RAGE) plays a pivotal role. We conducted a cross-sectional study to examine the relationships of circulating sRAGE, CRC and other clinical factors in type2 diabetes patients. METHODS: A total of 150 type 2 diabetes patients aged 50 years and older were enrolled, including 50 patients with CRC and 100 patients without CRC. We measured Serum levels of sRAGE and interleukin-6(IL-6) using an enzyme-linked immunosorbent assay (ELISA). In addition, other clinical parameters were also measured during hospitalization. RESULTS: Type 2 diabetes patients with CRC had higher triglyceride, total cholesterol, IL-6, and circulating sRAGE levels and lower use of medicines than type 2 diabetes patients without CRC. Circulating sRAGE was associated with an increased risk for CRC (OR = 2.289 for each SD increase in sRAGE, 95% CI = 1.037-5.051; P = 0.04) among Type 2 diabetes patients after adjustment for confounders. Furthermore, circulating sRAGE levels among type 2 diabetes patients were positively correlated with triglyceride (r = 0.377, P < 0.001), total cholesterol (r = 0.491, P < 0.001), and low-density lipoprotein cholesterol (LDL-c)(r = 0.330, P < 0.001) levels; the homeostatic model assessment for insulin resistance(HOMA-IR)score (r = 0.194, P = 0.017); and fasting serum insulin (r = 0.167, P = 0.041) and IL-6 (r = 0.311, P < 0.001) concentrations. CONCLUSIONS: Our results suggested that circulating sRAGE is independently risk factor for CRC, and also closely related to inflammation, dyslipidemia in type 2 diabetes patients.
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Biomarcadores/sangue , Neoplasias Colorretais/diagnóstico , Diabetes Mellitus Tipo 2/complicações , Receptor para Produtos Finais de Glicação Avançada/sangue , Idoso , Glicemia/análise , Neoplasias Colorretais/sangue , Neoplasias Colorretais/etiologia , Estudos Transversais , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , PrognósticoRESUMO
Currently, the development of stable electrochemical nitrogen reduction reaction (ENRR) catalysts with high N2 conversion activity and low cost to instead of the traditional Haber-Bosch ammonia production process of high-energy consumption remains a great challenge for researchers. Here, we have immobilized reductive closo-[B12H11]- boron clusters on a carbon nanotubes (CNT) surface and have successfully prepared a novel Au-CNT catalyst with extraordinary ENRR activity after adding HAuCl4 to the CNT-[B12H11]- precursor. The excellent properties of ammonia yield (57.7 µg h-1 cm-2) and Faradaic efficiency (11.97%) make it possible to achieve using this Au-CNT catalyst in large-scale industrial production of ammonia. Furthermore, its outstanding cyclic stability and long-term tolerability performance make it one of the most cost-effective catalysts to date. Here, by means of density functional theory we disclose the associative mechanism of N2-to-NH3 conversion on the Au(111) surface, providing visual theoretical support for the experimental results.
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Little is known about the molecular mechanisms underlying alveolar development. P311, a putative neuronal protein originally identified for its high expression during neuronal development, has once been reported to play a potential role in distal lung generation. However, the function of this protein has been poorly understood so far. Hence, we carried out a yeast two-hybrid screen, combining with other protein-protein interaction experiments, to isolate several binding partners of P311 during lung development, which may help us explore its function. We report 7 proteins here, including Gal-1, Loxl-1 and SPARC, etc, that can interact with it. Most of them have similar spatio-temporal expression patterns to P311. In addition, it was also found that P311 could stimulate their expression indirectly in L929 mouse fibroblast. Besides, computational methods were applied to construct a P311 centered protein-protein interaction network during alveolarization, using the 7 binding partners and their protein interaction information provided by public data resources. By analyzing the structure and function of this network, the effects of P311 on lung development were further clarified and all of the bioinformatic predictions from the network could be validated by real experiments. We have found here that P311 can control lung redox events, extracellular matrix and cell cycle progression, which are all crucial to pulmonary morphogenesis. This gives us a novel thought to explore the mechanisms controlling alveolarization.
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Proteínas de Transporte/genética , Pulmão/crescimento & desenvolvimento , Proteínas do Tecido Nervoso/genética , Organogênese/genética , Animais , Fibroblastos/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/genética , Pulmão/metabolismo , Camundongos , Neurônios/metabolismoRESUMO
The electricity provided by solar or wind power can drive nitrogen in the atmosphere, combining with ubiquitous water to form ammonia, and distributed production methods can alleviate the irreversible damage to the environment caused by the energy-intensive Haber-Bosch process. Here, we have designed a novel Ni-doped BCN heterojunction (S/M-BOPs-1) as a catalyst for the electrochemical nitrogen reduction reaction (NRR). The ammonia yield rate and Faraday efficiency in NRR driven by S/M-BOPs-1 reach up to 16.72 µg-1 h-1 cm-2 and 13.06%, respectively. Moreover, S/M-BOPs-1 still maintains high NRR activity and excellent stability after recycling for eight times and long-time operation of 12 h. Using density functional theory calculations, we reveal a possible NRR path for N2 to NH3 on Ni, BCN, and the S/M-BOPs-1 composite surfaces. The interaction between the BCN matrix and Ni nanoparticles promotes a synergetic effect for the electrochemical NRR efficiency due to the partial electron transfer from the Ni particles to BCN that inhibits hydrogen evolution reaction and decreases the rate-determining step on Ni surfaces toward NRR by â¼1.5 times. Therefore, efficient NRR performance can be achieved by tuning the electronic properties of non-noble metals via the formation of a heterointerface.
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Changes in histone H3 lysine 9 trimethylation (H3K9me3) may be related to the development of drugresistant acute myeloid leukaemia (AML); insights into the network of H3K9me3 may improve patient prognosis. Patient data were derived from the Gene Expression Omnibus (GEO) database and data from AML cells treated with chidamide, a novel benzamide chemical class of histone deacetylase inhibitor (HDACi), in vitro were derived from ChIPseq. Patients and AML cell data were analysed using GEO2R, GOseq, KOBAS, the STRING database and Cytoscape 3.5.1. We identified several genes related to the upregulation or downregulation of H3K9me3 in AML patients; some of these genes were related to apoptosis, autophagy, and the pathway of cell longevity. AML cells treated with chidamide in vitro showed the same gene changes. The protein interactions in the network did not have significantly more interactions than expected, suggesting the need for more research to identify these interactions. One compelling result from the protein interaction study was that sirtuin 1 (SIRT1) may have an indirect interaction with lysinespecific demethylase 4A (KDM4A). These results help explain alterations of H3K9me3 in AML that may direct further studies aimed at improving patient prognosis. These results may also provide a basis for chidamide as a treatment strategy for AML patients in the future.
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Aminopiridinas/uso terapêutico , Benzamidas/uso terapêutico , Biologia Computacional/métodos , Inibidores de Histona Desacetilases/uso terapêutico , Histonas/metabolismo , Leucemia Mieloide Aguda/tratamento farmacológico , Apoptose , Sequenciamento de Cromatina por Imunoprecipitação , Resistencia a Medicamentos Antineoplásicos , Redes Reguladoras de Genes , Humanos , Leucemia Mieloide Aguda/genética , Mapas de Interação de Proteínas , Células THP-1RESUMO
Direct conversion of methane to alcohol remains a key challenge. Here, we report a novel aqueous catalyst, cubic platinum (Pt) nanoparticles capped with Cs2[closo-B12H12], capable of direct oxidation of methane to ethanol and methanol with H2O2 and O2 under facile conditions. The selective conversion to ethanol exceeded 97% with a yield reaching 148.41 mol·kgcat-1·h-1 at 50 °C. Experiments with 5,5'-dimethy1-1-pyrroline-N-oxide (DMPO) and electron paramagnetic resonance (EPR) tests revealed that methane oxidation occurred via free-radical chain reactions involving CH3, CH3CH2, and HO radicals. Theoretical analysis suggested that the {1 0 0} surface of the Pt nanoparticles was capped with Cs2[closo-B12H12] mediated by Pt-B bonds with a binding energy of -278.6 kcal/mol. This promoted the growth of particles along the direction of the (1 0 0) facets and finally formed a cubic structure. The EPR tests combined with theoretical calculations confirmed the hypothesis that methane-ethane-ethanol conversion was mediated by the catalyst by employing the features of nano-platinum and Cs2[closo-B12H12], on which only C1 and C2 products were generated, while no products with three or more carbon atoms were detected in the reaction systems described above.
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The increasing global demands for eco-friendly and low-cost catalysts have propelled the advent of nanosized non-noble-metal catalysts to replace traditional noble metals. In this work, ultrafine NiO nanoparticles were prepared rapidly in situ by the strategy of transforming three-dimensional (3D) metal boron organic polymers (BOPs@Ni2+) to one-dimensional (1D) boron organic polymers (BOPs@Ni) nanorod arrays at room temperature. The 3D BOPs@Ni2+ can be quickly obtained by the interaction of 4,4'-bipyridine with Ni2+ and dodecaborate (B12H122-) in an aqueous solution. When Ni2+ is converted into NiO in situ, 1D BOPs@Ni nanostructure transformation from the 3D BOPs@Ni2+ framework was achieved due to the B-H···π interaction between B12H122- and 4,4'-bipyridine. Furthermore, BOPs@Ni exhibits high catalytic activity and rapid kinetics in the conversion of 4-nitrophenol to 4-aminophenol, and the high stability of 1D nanorod arrays guarantees the catalytic activity of BOP@Ni to barely change under recycling for at least 10 times. BOPs@Ni also exhibits good catalytic performance and high selectivity characteristics in the catalytic reduction of a series of nitrobenzene derivatives. This strategy of using BOPs@Ni2+ for loading self-supporting nanometal not only exhibits a highly efficient catalytic hydrogenation of nitrobenzene and its derivative but also provides an effective technical route for designing self-supported nanometal materials.
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On the basis of the unique chaotropic supramolecular assembly of cucurbit[5]uril (CB5) and dodecahydro- closo-dodecaborate anion [ closo-B12H12]2-, we have developed an efficient and universal platform to fabricate shape-controlled dodecaborate-based supramolecular organic frameworks (BOFs) decorated with ultrafine monodispersed trimetallic alloys. Simply by regulating the molar ratio of CB5 and [ closo-B12H12]2-, a series of fascinating morphologies, such as flowerlike structures, nanorods, nanocubes, and nanosheets, were successfully constructed. These obtained BOFs were proved to be good substrate supports for in situ synthesis of trimetallic PtCoNi nanoalloys, where the final PtCoNi-BOFs materials were obtained efficiently as a precipitate from aqueous solutions, and showed excellent catalytic performance in ammonia borane hydrolysis with a high turnover frequency of 1490 molH2 molPt-1 min-1 and a low activation energy of 15.79 kJ mol-1.
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Supramolecular nano-assemblies with tunable morphology have attracted extensive attention in composite material manufacturing and many other fields. Herein, a new class of shape-controlled dodecaborate-based supramolecular organic frameworks (BOFs), decorated with diverse ultrafine noble metal clusters (Au, Pd, Pt, Ag), has been successfully fabricated via the tunable host-guest assembly of cucurbit[n = 5,6,7,8]uril and Cs2[closo-B12H12]. Due to the unique dodecaborate-cucurbit[n]uril chaotropic effect, a breakthrough has been made in modulating the supramolecular frameworks in the urchin-like, network-like or octahedron-like structures without tedious chemical modifications or additional additives. More interestingly, Cs2[closo-B12H12], a prominent component in supramolecular structures, can also play dual roles as an excellent reductant and capping agent for the formation of metal clusters. The final product, i.e., BOFs decorated with ultrafine metal clusters (metal/BOFs) can be precipitated from aqueous solutions rapidly and they show high catalytic activity and recyclability in Suzuki reactions and in the selective reduction of furfural (FAL) to furfuryl alcohol (FOL).