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1.
Nucleic Acids Res ; 49(14): 8261-8276, 2021 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-34232997

RESUMO

Newly synthesized mRNA is translated during its export through the nuclear pore complex, when its 5'-cap structure is still bound by the nuclear cap-binding complex (CBC), a heterodimer of cap-binding protein (CBP) 80 and CBP20. Despite its critical role in mRNA surveillance, the mechanism by which CBC-dependent translation (CT) is regulated remains unknown. Here, we demonstrate that the CT initiation factor (CTIF) is tethered in a translationally incompetent manner to the perinuclear region by the DEAD-box helicase 19B (DDX19B). DDX19B hands over CTIF to CBP80, which is associated with the 5'-cap of a newly exported mRNA. The resulting CBP80-CTIF complex then initiates CT in the perinuclear region. We also show that impeding the interaction between CTIF and DDX19B leads to uncontrolled CT throughout the cytosol, consequently dysregulating nonsense-mediated mRNA decay. Altogether, our data provide molecular evidence supporting the importance of tight control of local translation in the perinuclear region.


Assuntos
RNA Helicases DEAD-box/genética , Fatores de Iniciação em Eucariotos/genética , Complexo Proteico Nuclear de Ligação ao Cap/genética , Proteínas de Transporte Nucleocitoplasmático/genética , Biossíntese de Proteínas , Citoplasma/genética , Células HeLa , Humanos , Degradação do RNAm Mediada por Códon sem Sentido/genética , Mapas de Interação de Proteínas/genética , Proteínas de Ligação ao Cap de RNA/genética , RNA Mensageiro/genética
2.
Nucleic Acids Res ; 49(21): 12517-12534, 2021 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-34850140

RESUMO

The pioneer (or first) round of translation of newly synthesized mRNAs is largely mediated by a nuclear cap-binding complex (CBC). In a transcriptome-wide analysis of polysome-associated and CBC-bound transcripts, we identify RN7SL1, a noncoding RNA component of a signal recognition particle (SRP), as an interaction partner of the CBC. The direct CBC-SRP interaction safeguards against abnormal expression of polypeptides from a ribosome-nascent chain complex (RNC)-SRP complex until the latter is properly delivered to the endoplasmic reticulum. Failure of this surveillance causes abnormal expression of misfolded proteins at inappropriate intracellular locations, leading to a cytosolic stress response. This surveillance pathway also blocks protein synthesis through RNC-SRP misassembled on an mRNA encoding a mitochondrial protein. Thus, our results reveal a surveillance pathway in which pioneer translation ensures proper targeting of endoplasmic reticulum and mitochondrial proteins.


Assuntos
Retículo Endoplasmático/metabolismo , Proteínas Mitocondriais/metabolismo , Biossíntese de Proteínas , Partícula de Reconhecimento de Sinal/metabolismo , Células HEK293 , Células HeLa , Humanos , Proteínas Mitocondriais/genética , Modelos Genéticos , Complexo Proteico Nuclear de Ligação ao Cap/genética , Complexo Proteico Nuclear de Ligação ao Cap/metabolismo , Polirribossomos/genética , Polirribossomos/metabolismo , Ligação Proteica , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ribossomos/genética , Ribossomos/metabolismo , Partícula de Reconhecimento de Sinal/genética , Transdução de Sinais/genética
3.
Bioorg Chem ; 128: 106072, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35944468

RESUMO

Three new amide alkaloids, piperlongumamides D-F (14, 19, and 32); a new piperic ester, piperlongumester A (45); and two new natural compounds, methyl (2E,4Z)-5-(1,3-benzodioxol-5-yl)penta-2,4-dienoate (46) and trans-piperolein B ester (47), along with 41 known compounds were isolated from the fruits of Piper longum L. Their structures were identified by analyzing spectroscopic data, including mass spectrometry, 1D, and 2D NMR data. The anti-inflammatory and cytotoxic activities of all isolated compounds (1-47) were evaluated. Compounds 3, 6, and 19 inhibited nitric oxide production with IC50 values of 16.1 ± 0.94, 14.5 ± 0.57, and 27.3 ± 1.11 µM, respectively, whereas compound 1 exhibited strong cytotoxic activity toward three ovarian cancer cell lines A2780, TOV-112D, and SK-OV3, with IC50 values of 6.7 ± 0.77, 5.8 ± 0.29, and 48.3 ± 0.40 µM, respectively. Molecular docking simulations were performed to identify the interaction and binding mechanisms of these active metabolites with proteins related to inflammation and cancer.


Assuntos
Alcaloides , Antineoplásicos , Neoplasias Ovarianas , Piper , Alcaloides/química , Amidas/química , Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Ésteres/farmacologia , Feminino , Frutas/química , Humanos , Simulação de Acoplamento Molecular , Estrutura Molecular , Neoplasias Ovarianas/tratamento farmacológico , Piper/química
4.
Nucleic Acids Res ; 47(17): 9313-9328, 2019 09 26.
Artigo em Inglês | MEDLINE | ID: mdl-31361897

RESUMO

Newly synthesized mRNAs are exported from the nucleus to cytoplasm with a 5'-cap structure bound by the nuclear cap-binding complex (CBC). During or after export, the CBC should be properly replaced by cytoplasmic cap-binding protein eIF4E for efficient protein synthesis. Nonetheless, little is known about how the replacement takes place. Here, we show that double-stranded RNA-binding protein staufen1 (STAU1) promotes efficient replacement by facilitating an association between the CBC-importin α complex and importin ß. Our transcriptome-wide analyses and artificial tethering experiments also reveal that the replacement occurs more efficiently when an mRNA associates with STAU1. This event is inhibited by a key nonsense-mediated mRNA decay factor, UPF1, which directly interacts with STAU1. Furthermore, we find that cellular apoptosis that is induced by ionizing radiation is accompanied by inhibition of the replacement via increased association between STAU1 and hyperphosphorylated UPF1. Altogether, our data highlight the functional importance of STAU1 and UPF1 in the course of the replacement of the CBC by eIF4E, adding a previously unappreciated layer of post-transcriptional gene regulation.


Assuntos
Proteínas do Citoesqueleto/genética , Fator de Iniciação 4E em Eucariotos/genética , Biossíntese de Proteínas/genética , RNA Helicases/genética , Proteínas de Ligação a RNA/genética , Transativadores/genética , Regiões 5' não Traduzidas , Núcleo Celular/genética , Citoplasma/genética , Citoplasma/metabolismo , Humanos , Complexo Proteico Nuclear de Ligação ao Cap/genética , Proteínas de Ligação ao Cap de RNA/genética , Estabilidade de RNA/genética , RNA Mensageiro/genética
5.
J Radiol Prot ; 40(3): 774-789, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32503019

RESUMO

In order to shield neutron and gamma rays efficiently, a multilayer model is designed with metal hydrides and heavy metals and is analysed based on Monte Carlo simulations. In terms of shielding performance, the hydrogen in metal hydrides acts as a moderator to slow down the neutron energy and heavy metals are good for absorbing gamma rays. A simulation and calculational analysis are carried out with various parameters such as spectrum change, shield thickness, and number of multilayers. In addition, the rate of DPA (displacement per atom) is analysed to estimate both the lifetime and radiation resistance with the MCNP code. From lots of simulations, ZrH2 and W couples are the best candidate especially for shielding gamma rays, while TiH2 with W is good for neutron shielding. The concept of multilayer metal hydride such as TiH2 and ZrH2 coupled with W could be one of best combinations to shield both neutron and gamma-rays in many nuclear facilities such as nuclear reactor, fusion reactor and other applications.


Assuntos
Hidrogênio/química , Metais Pesados/química , Proteção Radiológica/instrumentação , Simulação por Computador , Raios gama , Método de Monte Carlo , Nêutrons
6.
Apoptosis ; 23(11-12): 707-709, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30293220

RESUMO

The original version of this article contained a mistake. The bands for HA Tag and t-ERK in Figs. 2d, 2h, 3d are incorrect. The author informs that these errors had no influence in the scientific content of the paper. The corrected figures (Figs. 2 and 3) are given below.

7.
Dis Esophagus ; 30(1): 1-5, 2017 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-26822541

RESUMO

Ectopic sebaceous glands in the esophagus have rarely been reported and, thus, represent an obscure medical condition. The aim of this study is to identify the prevalence rate and clinical characteristics of this lesion in an asymptomatic population. We prospectively enrolled health screen examinees who underwent esophagogastroduodenoscopy for gastric cancer screening. An esophageal biopsy was performed in the cases in which esophageal ectopic sebaceous glands were suspected. The general characteristics of the examinees were analyzed based on their medical records. A total of 9989 examinees were enrolled, and five examinees were diagnosed with esophageal ectopic sebaceous glands between December 2012 and June 2014. The endoscopic findings of the esophageal ectopic sebaceous glands indicated multiple yellowish patches or papules, which varied in size. The histopathological findings indicated several lobulated sebaceous glands in the squamous epithelium with inflammatory infiltration. The follow-up endoscopic findings indicated that there was no grossly discernible change. In conclusion, esophageal ectopic sebaceous glands are present in 0.05% of asymptomatic subjects. This lesion is thought to be benign and is not related to clinical symptoms. Therefore, esophageal ectopic sebaceous glands do not require further treatment or follow-up, which makes endoscopists free from active efforts for differential diagnosis with other malignant diseases.


Assuntos
Doenças Assintomáticas , Coristoma/epidemiologia , Doenças do Esôfago/epidemiologia , Esôfago/patologia , Glândulas Sebáceas , Adulto , Coristoma/patologia , Endoscopia do Sistema Digestório , Doenças do Esôfago/patologia , Neoplasias Esofágicas/epidemiologia , Esofagite/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Papiloma/epidemiologia , Pólipos/epidemiologia , Prevalência , Estudos Prospectivos , República da Coreia/epidemiologia
8.
Biochem Biophys Res Commun ; 478(3): 1396-402, 2016 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-27569281

RESUMO

Parkinson's disease (PD) is the second most common neurodegenerative disorder of aging. PD involves a progressive loss of dopaminergic neurons in the substantia nigra pars compacta. 1-Methyl-4-phenyl-1, 2, 3, 6-tetrahydropyidine (MPTP) and its toxic metabolite 1-methyl-4-phenylpyridinium ion (MPP+) inhibit the complex I of the mitochondrial electron transport chain, and have been widely used to construct PD models. Cyclophilin B (CypB) is an endoplasmic reticulum protein that binds to cyclosporine A as a cyclophilin family member. CypB has peptidyl-prolyl cis-trans isomerase (PPIase) activity. We investigated the protective effects of overexpressed CypB on MPP+-induced neurocytotoxicity in SH-SY5Y human neuroblastoma cells. Overexpressed CypB decreased MPP(+)-induced oxidative stress through the modulation of antioxidant enzymes including manganese superoxide dismutase and catalase, and prevented neurocytotoxicity via mitogen-activated protein kinase, especially the c-Jun N-terminal kinase pathway. In addition, CypB inhibited the activation of MPP(+)-induced the pro-apoptotic molecules poly (ADP-ribose) polymerase, Bax, and Bcl-2, and attenuated MPP(+)-induced mitochondrial dysfunction. The data suggest that overexpressed CypB protects neuronal cells from MPP+-induced dopaminergic neuronal cell death.


Assuntos
1-Metil-4-fenilpiridínio/toxicidade , Ciclofilinas/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Neuroblastoma/patologia , Fármacos Neuroprotetores/metabolismo , Neurotoxinas/toxicidade , Morte Celular , Linhagem Celular Tumoral , Humanos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Estresse Oxidativo/efeitos dos fármacos
9.
Apoptosis ; 19(9): 1399-410, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25052841

RESUMO

Apelin, which is an endogenous ligand for the orphan G-protein-coupled receptor APJ, was reported to be up-regulated by hypoxia-inducible factor 1-α (HIF1-α) in hypoxia- and insulin-treated cell systems. However, a negative transcriptional regulator of apelin has not yet been identified. In this study, we showed that apelin is down-regulated by ATF4 via the pro-apoptotic p38 MAPK pathway under endoplasmic reticulum (ER) stress. First, we analyzed the human apelin promoter to characterize the effects of ER stress on apelin expression in hepatocytes. Treatment with thapsigargin, an inducer of ER stress, and over-expression of ATF4 decreased apelin expression in hepatocytes. This work identified an ATF4-responsive region within the apelin promoter. Interestingly, ATF4-mediated repression of apelin was dependent upon the N-terminal domain of ATF4. C/EBP-ß knockdown experiments suggest that C/EBP-ß, which acts as an ATF4 binding partner, is critical for the ER stress-induced down-regulation of apelin. We also demonstrated that ATF4 regulates apelin gene expression via p38 pathways. Ectopic expression of constitutively active MKK6, an upstream kinase of p38, suggested that activation of the p38 pathway is sufficient to induce ATF4-mediated repression of apelin. Moreover, apelin enhanced cell migration in a wound healing assay in a p38 MAPK-dependent manner. Furthermore, analysis of caspase-3 activation indicated that ATF4 knockdown up-regulated apelin expression, leading to the inability of MKK6 (CA) to exert pro-apoptotic effects. Taken together, our results suggest that ATF4-mediated repression of apelin contributes substantially to the pro-apoptotic effects of p38.


Assuntos
Fator 4 Ativador da Transcrição/genética , Estresse do Retículo Endoplasmático , Peptídeos e Proteínas de Sinalização Intercelular/genética , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Fator 4 Ativador da Transcrição/metabolismo , Apelina , Apoptose , Proteína beta Intensificadora de Ligação a CCAAT/genética , Proteína beta Intensificadora de Ligação a CCAAT/metabolismo , Caspase 3/metabolismo , Movimento Celular , Regulação para Baixo , Inibidores Enzimáticos/farmacologia , Células Hep G2 , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , MAP Quinase Quinase 6/metabolismo , Sistema de Sinalização das MAP Quinases , Regiões Promotoras Genéticas , Tapsigargina/farmacologia
10.
Biochem Biophys Res Commun ; 454(4): 518-23, 2014 11 28.
Artigo em Inglês | MEDLINE | ID: mdl-25451271

RESUMO

Accumulating evidence suggests that endoplasmic reticulum (ER) stress plays a major role in the development of many diseases. A previous study indicated that the apoptotic regulator p53 is significantly increased in response to ER stress and participates in ER stress-induced apoptosis. However, the regulators of p53 expression during ER stress are still not fully understood. Here, we investigated whether p53 contributes to the impairment of Pin1 signaling under ER stress. We found that treatment with thapsigargin, a stimulator of p53 expression and an inducer of ER stress, decreased Pin1 expression in HCT116 cells. Also, we identified functional p53 response elements (p53REs) in the Pin1 promoter. Overexpression of p53 significantly decreased Pin1 expression in HCT116 cells while abolition of p53 gene expression induced Pin1 expression. Pin1 expression was significantly increased by treatment with the p53 inhibitor pifithrin-α or down-regulation of p53 expression. Taken together, ER stress decreased Pin1 expression through p53 activation, and this mechanism may be associated with ER stress-induced cell death. These data reported here support the importance of Pin1 as a potential target molecule mediating tumor development.


Assuntos
Estresse do Retículo Endoplasmático , Regulação Enzimológica da Expressão Gênica , Peptidilprolil Isomerase de Interação com NIMA/biossíntese , Peptidilprolil Isomerase de Interação com NIMA/genética , Proteína Supressora de Tumor p53/metabolismo , Apoptose , Sobrevivência Celular , Células Cultivadas , Células HCT116 , Humanos , Peptidilprolil Isomerase de Interação com NIMA/metabolismo
11.
J Nanosci Nanotechnol ; 14(11): 8867-72, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25958619

RESUMO

Copper-containing mesoporous carbons (XCu-MC) with different copper content (X = 8.0, 12.7, 15.9, 23.3, and 26.8 wt%) were prepared by a single-step surfactant-templating method. Rhenium nano-catalysts supported on copper-containing mesoporous carbons (Re/XCu-MC) were then prepared by an incipient wetness method. Re/XCu-MC (X = 8.0, 12.7, 15.9, 23.3, and 26.8 wt%) catalysts were characterized by nitrogen adsorption-desorption isotherm, HR-TEM, FT-IR, and H2- TPR analyses. Liquid-phase hydrogenation of succinic acid to 1,4-butanediol (BDO) via dimethyl succinate (DMS) was carried out over Re/XCu-MC catalysts in a batch reactor. The effect of copper content on the physicochemical properties and catalytic activities of Re/XCu-MC catalysts in the hydrogenation of succinic acid to BDO was investigated. Re/XCu-MC catalysts retained different physicochemical properties depending on copper content. In the hydrogenation of succinic acid to BDO, yield for BDO showed a volcano-shaped trend with respect to copper content. Thus, an optimal copper content was required to achieve maximum catalytic performance of Re/XCu-MC. It was also observed that yield for BDO increased with increasing the amount of hydrogen consumption by copper in the Re/XCu-MC catalysts.


Assuntos
Butileno Glicóis/química , Cobre/química , Nanopartículas Metálicas/química , Rênio/química , Ácido Succínico/química , Butileno Glicóis/análise , Carbono/química , Hidrogenação , Succinatos/química , Ácido Succínico/análise
12.
J Nanosci Nanotechnol ; 14(11): 8884-90, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25958622

RESUMO

Cesium-exchanged Cs(x)H(3.0-x)PW12O40 (X = 2.0, 2.3, 2.5, 2.8, and 3.0) heteropolyacid nanocatalysts were prepared, and they were applied to the catalytic decomposition of lignin model compound to aromatics. Successful formation of cesium-exchanged Cs(x)H(3.0-x)PW12O40 (X = 2.0-3.0) catalysts was confirmed by FT-IR, ICP-AES, and XRD measurements. 2,3-Dihydrobenzofuran was employed as a lignin model compound for representing ß-5 bond in lignin. Phenol, ethylbenzene, and 2-ethylphenol were mainly produced by the catalytic decomposition of 2,3-dihydrobenzofuran. Conversion of 2,3-dihydrobenzofuran and total yield for main products (phenol, ethylbenzene, and 2-ethylphenol) were closely related to the surface acidity of Cs(x)H(3.0-x)PW12O40 (X = 2.0-3.0) catalysts. Conversion of 2,3-dihydrobenzofuran and total yield for main products increased with increasing surface acidity of the catalysts. Among the catalysts tested, Cs2.5H0.5PW12O40 with the largest surface acidity showed the highest conversion of 2,3-dihydrobenzofuran and the highest total yield for main products. These results indicate that surface acidity of Cs(x)H(3.0-x)PW12O40 (X = 2.0-3.0) catalysts served as an important factor determining the catalytic performance in the decomposition of 2,3-dihydrobenzofuran to aromatics.


Assuntos
Derivados de Benzeno/química , Benzofuranos/química , Césio/química , Nanoestruturas/química , Ácidos , Derivados de Benzeno/análise , Benzofuranos/análise , Lignina , Propriedades de Superfície
13.
BMC Complement Altern Med ; 14: 419, 2014 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-25345853

RESUMO

BACKGROUND: Osteopontin (OPN) is one of important molecular targets in cancer progression, metastasis as a calcium-binding, extracellular-matrix-associated protein of the small integrin-binding ligand and, N-linked glycoprotein. In the present study, anti-metastatic mechanism of ethanol extracts of Ocimum sanctum (EEOS) was elucidated on OPN enhanced metastasis in NCI-H460 non- small cell lung cancer cells. METHODS: Cell viability was measured by MTT assay. Adhesion and invasion assays were carried out to see that EEOS inhibited cell adhesion and invasion in OPN treated and non-treated NCI-H 460 cells. RT-PCR was used to determine the mRNA levels of uPA, uPAR, and EGFR. RESULTS: EEOS significantly inhibited cell adhesion and invasion in OPN treated and non treated NCI-H460 cells, though EEOS did not show any toxicity up to 200 µg/ml. EEOS effectively attenuated the expression of OPN and CD44 and also OPN activated the expression of CD44 in NCI-H460 cells. In addition, EEOS effectively suppressed the expression of phosphatidylinositide 3-kinases (PI3K) and cyclooxygenase 2 (COX-2) and the phosphorylation of Akt at protein level in OPN treated NCI-H460 cells. Also, EEOS significantly attenuated the expression of urokinase plasminogen activator (uPA), its receptor (uPAR) and epidermal growth factor receptor (EGFR) at mRNA level and reduced vascular endothelial growth factor (VEGF) production and MMP-9 activity in OPN treated NCI-H460 cells. Furthermore, PI3K/Akt inhibitor LY294002 enhanced anti-metastatic potential of EEOS to attenuate the expression of uPA and MMP-9 in OPN treated NCI-H 460 cells. CONCLUSION: Overall, our findings suggest that anti-metastatic mechanism of EEOS is mediated by inhibition of PI3K/Akt in OPN treated NCI-H460 non-small cell lung cancer cells.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Ocimum/química , Osteopontina/genética , Osteopontina/metabolismo , Extratos Vegetais/farmacologia , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/fisiopatologia , Adesão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Humanos , Metástase Neoplásica , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo
14.
J Oral Implantol ; 40 Spec No: 375-9, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25020219

RESUMO

Perforation of the Schneiderian membrane constitutes a major intraoperative complication of maxillary sinus floor elevation with graft materials, but postoperative perforation of the sinus membrane is very rare. This case report demonstrates that conservative treatment involving drainage and the administration of systemic antibiotics can be used to successfully treat postoperative sinus membrane perforation with infection of the graft material.


Assuntos
Seio Maxilar/patologia , Mucosa Nasal/patologia , Complicações Pós-Operatórias , Levantamento do Assoalho do Seio Maxilar/efeitos adversos , Infecção da Ferida Cirúrgica/etiologia , Adulto , Autoenxertos/transplante , Substitutos Ósseos/uso terapêutico , Transplante Ósseo/métodos , Implantação Dentária Endóssea/métodos , Implantes Dentários , Seguimentos , Humanos , Masculino , Fístula Bucal/etiologia , Fístula do Sistema Respiratório/etiologia , Irrigação Terapêutica/métodos
15.
J Environ Sci (China) ; 26(6): 1325-31, 2014 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-25079844

RESUMO

Effluent organic matter (EfOM) is the major cause of fouling in the low pressure membranes process for wastewater reuse. Coagulation and oxidation of biological wastewater treatment effluent have been applied for the fouling control of microfiltration membranes. However, the change in EfOM structure by pre-treatments has not been clearly identified. The changes of EfOM characteristics induced by coagulation and ozonation were investigated through size exclusion chromatography, UV/Vis spectrophotometry, fluorescence spectrophotometry and titrimetric analysis to identify the mechanisms in the reduction of ultrafiltration (UF) membrane fouling. The results indicated that reduction of flux decline by coagulation was due to modified characteristics of dissolved organic carbon (DOC) content. Total concentration of DOC was not reduced by ozonation. However, the mass fraction of the molecules with molecular weight larger than 5 kDa, fluorescence intensity, aromaticity, highly condensed chromophores, average molecular weight and soluble microbial byproducts decreased greatly after ozonation. These results indicated that EfOM was partially oxidized by ozonation to low molecular weight, highly charged compounds with abundant electron-withdrawing functional groups, which are favourable for alleviating UF membrane flux decline.


Assuntos
Membranas Artificiais , Compostos Orgânicos/análise , Ozônio/química , Cromatografia em Gel , Floculação , Espectrometria de Fluorescência , Espectrofotometria , Ultrafiltração , Qualidade da Água
16.
Sci Rep ; 14(1): 12168, 2024 05 28.
Artigo em Inglês | MEDLINE | ID: mdl-38806510

RESUMO

The bioartificial liver (BAL) system can potentially rescue acute liver failure (ALF) patients by providing partial liver function until a suitable donor liver can be found or the native liver has self-regenerated. In this study, we established a suitable cryopreservation process for the development of an off-the-shelf BAL system. The viability of hepatocyte spheroids cryopreserved in liquid nitrogen was comparable to that of fresh primary hepatocyte spheroids. When hepatocyte spheroids were subjected to cryopreservation in a deep freezer, no statistically significant differences were observed in ammonia removal rate or urea secretion rate based on the cryopreservation period. However, the functional activity of the liver post-cryopreservation in a deep freezer was significantly lower than that observed following liquid nitrogen cryopreservation. Moreover, cryopreserving spheroid hydrogel beads in a deep freezer resulted in a significant decrease (approximately 30%) in both ammonia removal and urea secretion rates compared to the group cryopreserved in liquid nitrogen. The viabilities of spheroid hydrogel beads filled into the bioreactor of a BAL system were similar across all four groups. However, upon operating the BAL system for 24 h, the liver function activity was significantly higher in the group comprising hydrogel beads generated after thawing hepatocyte spheroids cryopreserved in liquid nitrogen. Consequently, the manufacturing of beads after the cryopreservation of hepatocyte spheroids is deemed the most suitable method, considering efficiency, economic feasibility, and liver function activity, for producing a BAL system.


Assuntos
Criopreservação , Hepatócitos , Fígado Artificial , Esferoides Celulares , Hepatócitos/metabolismo , Hepatócitos/citologia , Criopreservação/métodos , Esferoides Celulares/metabolismo , Esferoides Celulares/citologia , Animais , Sobrevivência Celular , Masculino , Temperatura , Ratos , Ureia/metabolismo , Humanos , Amônia/metabolismo , Falência Hepática Aguda/terapia , Falência Hepática Aguda/metabolismo , Fígado/metabolismo , Fígado/citologia
17.
J Nanosci Nanotechnol ; 13(12): 8121-6, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24266203

RESUMO

Etherification of n-butanol to di-n-butyl ether was carried out over various structural classes of heteropolyacid (HPA) catalysts, including Keggin- (H3PW12O40), Wells-Dawson- (H6P2W18O62), and Preyssler-type (H14[NaP5W30O110]) HPA catalysts. Successful formation of HPA catalysts was well confirmed by FT-IR, 31P NMR, and ICP-AES analyses. Acid properties of HPA catalysts were determined by NH3-TPD (temperature-programmed desorption) measurements. Acid strength of the catalysts increased in the order of H14[NaP5W30O110] < H6P2W18O62 < H3PW12O40. The catalytic performance of HPA catalysts was closely related to the acid strength of the catalysts. In the etherification of n-butanol to di-n-butyl ether over various structural classes of HPA catalysts, Conversion of n-butanol and yield for di-n-butyl ether increased with increasing acid strength of HPA catalysts. Among the catalysts tested, Keggin-type (H3PW12O40) HPA catalyst with the strongest acid strength showed the best catalytic performance. Acid strength of HPAs served as an important factor determining the catalytic performance in the etherification of n-butanol to di-n-butyl ether.

18.
Apoptosis ; 17(8): 784-96, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22555451

RESUMO

Cyclophilin, a cytosolic receptor for the immunosuppressive drug cyclosporin A, plays a role in diverse pathophysiologies along with its receptor, CD147. Although the interaction between cyclophilin A and CD147 is well established in inflammatory disease, that of cyclophilin B (CypB) with CD147 has not been fully explored, especially in cancer cell biology, and the exact molecular mechanism underlying such an association is poorly understood. In this study, we first identified high expression levels of CypB in 54 % of hepatocellular carcinoma patient tissues but in only 12.5 % of normal liver tissues. Then, we demonstrated that CypB overexpression protects human hepatoma cells against oxidative stress through its binding to CD147; this protective effect depends on the peptidyl prolyl isomerase activity of CypB. siRNA-mediated knockdown of CypB expression rendered hepatoma cells more vulnerable to ROS-mediated apoptosis. Furthermore, we also determined that a direct interaction between secreted CypB and CD147 regulates the extracellular signal-regulated kinase intracellular signaling pathway and is indispensible for the protective functions of CypB. For the first time, we demonstrated that CypB has an essential function in protecting hepatoma cells against oxidative stress through binding to CD147 and regulating the ERK pathway.


Assuntos
Basigina/metabolismo , Carcinoma Hepatocelular/metabolismo , Ciclofilinas/metabolismo , Neoplasias Hepáticas/metabolismo , Sistema de Sinalização das MAP Quinases , Estresse Oxidativo , Apoptose , Proteínas Reguladoras de Apoptose/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular , Ciclofilinas/genética , Ativação Enzimática , Feminino , Expressão Gênica , Humanos , Peróxido de Hidrogênio/metabolismo , Peróxido de Hidrogênio/farmacologia , Masculino , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Fosforilação , Processamento de Proteína Pós-Traducional , Análise Serial de Tecidos
19.
Nat Commun ; 13(1): 653, 2022 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-35115527

RESUMO

Mitochondria are energy-generating organelles and mitochondrial biogenesis is stimulated to meet energy requirements in response to extracellular stimuli, including exercise. However, the mechanisms underlying mitochondrial biogenesis remain unknown. Here, we demonstrate that transcriptional coactivator with PDZ-binding motif (TAZ) stimulates mitochondrial biogenesis in skeletal muscle. In muscle-specific TAZ-knockout (mKO) mice, mitochondrial biogenesis, respiratory metabolism, and exercise ability were decreased compared to wild-type mice. Mechanistically, TAZ stimulates the translation of mitochondrial transcription factor A via Ras homolog enriched in brain (Rheb)/Rheb like 1 (Rhebl1)-mTOR axis. TAZ stimulates Rhebl1 expression via TEA domain family transcription factor. Rhebl1 introduction by adeno-associated virus or mTOR activation recovered mitochondrial biogenesis in mKO muscle. Physiologically, mKO mice did not stimulate exercise-induced mitochondrial biogenesis. Collectively, our results suggested that TAZ is a novel stimulator for mitochondrial biogenesis and exercise-induced muscle adaptation.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas de Ligação a DNA/genética , Mitocôndrias Musculares/genética , Proteínas Mitocondriais/genética , Biogênese de Organelas , Condicionamento Físico Animal , Fatores de Transcrição/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Linhagem Celular , Células Cultivadas , DNA Mitocondrial/genética , DNA Mitocondrial/metabolismo , Proteínas de Ligação a DNA/metabolismo , Embrião de Mamíferos/citologia , Embrião de Mamíferos/metabolismo , Fibroblastos/citologia , Fibroblastos/metabolismo , Células HEK293 , Humanos , Camundongos Knockout , Mitocôndrias Musculares/metabolismo , Proteínas Mitocondriais/metabolismo , Músculo Esquelético/citologia , Músculo Esquelético/metabolismo , Mioblastos/citologia , Mioblastos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Fatores de Transcrição/metabolismo
20.
Bioengineering (Basel) ; 9(12)2022 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-36550944

RESUMO

To use hepatocytes immediately when necessary for hepatocyte transplantation and bioartificial liver (BAL) systems, a serum-free cryopreservation protocol ensuring the high survival of hepatocytes and maintenance of their functions should be developed. We established a serum-free protocol for the cryopreservation of primary hepatocytes, hepatocyte spheroids, and hepatocyte spheroid beads in liquid nitrogen. The serum-free cryopreservation solutions showed a significantly higher performance in maintaining enhanced viability and ammonia removal, urea secretion, and the albumin synthesis of hepatocyte spheroids and spheroid beads. The serum-free thawing medium, containing human serum albumin (HSA) and N-acetylcysteine (NAC), was compared with a fetal bovine serum-containing thawing medium for the development of a serum-free thawing medium. Our results show that hepatocyte spheroids and spheroid beads thawed using a serum-free thawing medium containing HSA and NAC exhibited increased hepatocyte viability, ammonia removal, urea secretion, and albumin synthesis compared to those thawed using the serum-containing medium. Finally, we evaluated the liver functions of the cryopreserved BAL system-applied serum-free cryopreservation process compared to the fresh BAL system. The ammonia removal efficiency of the cryopreserved hepatocyte spheroids BAL was lower than or similar to that of the fresh BAL system. Additionally, the urea concentrations in the media of all three BAL systems were not significantly different during BAL system operation. This cryopreserved spheroid-based BAL system using a serum-free process will be a good candidate for the treatment of patients.

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