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1.
Nat Prod Res ; : 1-8, 2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38318698

RESUMO

The scarcity of more effective wild ginseng has severely limited its use, culturing of adventitious roots from wild ginseng were its good substitute. In this study, we found ginsenoside Rf as the special component in adventitious roots extract significantly decreased melanin levels and tyrosinase activity in B16F10 cells and zebrafish, and suppressed the expression of microphthalmia-associated transcription factor and melanogenic enzymes in B16F10 cells. Notably, Rf treatment of B16F10 cells led to reduced cell levels of adenosine cyclic 3', 5'-monophosphate (cAMP), nitric oxide (NO), and guanoside cyclic 3', 5'-monophosphate (cGMP), and reduced activities of adenylate cyclase (AC), protein kinase A (PKA), guanylate cyclase (GC), and protein kinase G (PKG), which suggest Rf anti-melanogenic activity potentially involved inhibition of AC/cAMP/PKA and NO/GC/cGMP/PKG signalling pathway. This work provides experimental basis for skin-lightening effect of wild ginseng adventitious roots and their functional part.

2.
J Med Biochem ; 42(3): 484-491, 2023 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-37790206

RESUMO

Background: To investigate the efficacy and safety of singleand double-volume exchange transfusion for neonatal hyperbilirubinemia (HB) and compare their effects on the internal environment of newborns. Methods: The clinical data of 96 HB newborns admitted to and treated in our hospitals from January 2016 to October 2021 were retrospectively analyzed. Then, these newborns were divided into single volume group (80-110 mL/kg, n=48) and double volume group (150-180 mL/kg, n=48) by the exchange volume per unit body mass. The hematological indicators total serum bilirubin (TSB), peripheral blood red blood cell (RBC) count, white blood cell (WBC) count, platelet (PLT) count, serum albumin (ALB), prothrombin time (PT) and activated partial thromboplastin time (APTT), and changes in inner-environment indexes (blood gas, blood glucose, acid-base and electrolyte levels) were compared between the two groups of newborns before treatment and after once treatment. Additionally, the adverse reactions of exchange transfusion in the two groups of newborns were recorded.

3.
Molecules ; 29(1)2023 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-38202694

RESUMO

The cultivation of ginseng in fields is time-consuming and labor-intensive. Thus, culturing adventitious ginseng root in vitro constitutes an effective approach to accumulating ginsenosides. In this study, we employed UPLC-QTOF-MS to analyze the composition of the cultured adventitious root (cAR) of ginseng, identifying 60 chemical ingredients. We also investigated the immunomodulatory effect of cAR extract using various mouse models. The results demonstrated that the cAR extract showed significant activity in enhancing the immune response in mice. The mechanism underlying the immunomodulatory effect of cAR was analyzed through network pharmacology analysis, revealing potential 'key protein targets', namely TNF, AKT1, IL-6, VEGFA, and IL-1ß, affected by potential 'key components', namely the ginsenosides PPT, F1, Rh2, CK, and 20(S)-Rg3. The signaling pathways PI3K-Akt, AGE-RAGE, and MAPK may play a vital role in this process.


Assuntos
Ginsenosídeos , Panax , Animais , Camundongos , Ginsenosídeos/farmacologia , Fosfatidilinositol 3-Quinases , Modelos Animais de Doenças , Extratos Vegetais/farmacologia
5.
Oxid Med Cell Longev ; 2022: 6434086, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35927993

RESUMO

The cerebral ischemic microvascular response and collateral circulation compensatory capacity are important for the outcome of ischemic stroke. Here, we sought to evaluate the effect of a linarin derivate 4'-benzylapigenin-7-ß-rutinoside (BLR) on neurological function and cerebral blood flow restoration in ischemic stroke. A mouse model of middle cerebral artery occlusion (30 min) with reperfusion (24 h) was used to mimic ischemic stroke in vivo, and 2,3,5-triphenyltetrazolium chloride (TTC) staining, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays, and immunofluorescence microscopy were used to assess the protective effects of BLR on infarct volume, neurological function, neuronal apoptosis, and inflammatory damage. Cerebral blood flow was assayed by laser speckle contrast imaging. Double immunostaining of GFAP-collagen IV and brain lucidification were performed to determine the protective effects of BLR on the disruption of brain vasculature. Differential gene expression was assessed by RNA sequencing. Coimmunoprecipitation and western blotting were used to explore the mechanism of BLR-induced neuroprotection. The results of in vivo experiments showed that BLR administration after reperfusion onset reduced infarct volume, improved neurological function, and decreased the neural cell apoptosis and inflammatory response in the ischemic brain, which was accompanied by increased cerebral blood flow and reduced detachment of astrocyte endfeet from the capillary basement membrane. The RNA sequencing data showed that BLR promoted the upregulation of extracellular matrix and angiogenesis pathway-related genes; in particular, BLR significantly increased the expression of the chondroitin sulfate proteoglycan 4 (CSPG4) gene, enhanced the membrane location of CSPG4, and promoted its downstream signaling protein expression, which is associated with KDEL receptor (KDELR) activation. In addition, activated KDELR further increased the phosphorylation of mitogen-activated protein kinases after BLR treatment. Taken together, our data showed that BLR could protect against ischemic brain injury and may serve as a new promising therapeutic candidate drug for ischemic stroke, and that KDELR might act as both a sensor and effector to activate CSPG4 to increase cerebral blood flow.


Assuntos
Isquemia Encefálica , AVC Isquêmico , Traumatismo por Reperfusão , Animais , Antígenos , Apoptose , Isquemia Encefálica/metabolismo , Circulação Cerebrovascular , Glicosídeos , Infarto da Artéria Cerebral Média/complicações , Infarto da Artéria Cerebral Média/tratamento farmacológico , Camundongos , Proteoglicanas , Receptores de Peptídeos , Traumatismo por Reperfusão/metabolismo
6.
J Biophotonics ; 15(5): e202100329, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35000293

RESUMO

The ability to unveil molecular specificities of endogenous nonfluorescent chromophores of ultraviolet photoacoustic imaging technology enables label-free histology imaging of tissue specimens. In this work, we exploit ultraviolet photoacoustic microscopy for identifying human glioma xenograft of mouse brain ex vivo. Intrinsically excellent imaging contrast of cell nucleus at ultraviolet photoacoustic illumination along with good spatial resolution allows for discerning the brain glioma of freshly-harvested thick brain slices, which circumvents laborious time-consuming preparations of the tissue specimens including micrometer-thick slicing and H&E staining that are prerequisites in standard histology analysis. The identification of tumor margins and quantitative analysis of tumor areas is implemented, representing good agreement with the standard H&E-stained observations. Quantitative ultraviolet photoacoustic microscopy can access fast pathological assessment to the brain tissues, and thus potentially facilitates intraoperative brain tumor resection to precisely remove all cancerous cells and preserve healthy tissue for maintaining its essential function.


Assuntos
Neoplasias Encefálicas , Glioma , Técnicas Fotoacústicas , Animais , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Neoplasias Encefálicas/patologia , Glioma/patologia , Xenoenxertos , Humanos , Camundongos , Microscopia/métodos , Técnicas Fotoacústicas/métodos
7.
ACS Appl Mater Interfaces ; 13(39): 46213-46224, 2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34546708

RESUMO

Acute ischemic stroke has become the major cause of mortality and disability worldwide. Following ischemic stroke, the reperfusion injury is mainly mediated by the burst of reactive oxygen and nitrogen species (RONS). Therefore, blocking the excessive production or removing RONS holds great promise as a potential therapeutic strategy. Herein, we developed a Co-doped Fe3O4 nanozyme that is capable of scavenging H2O2, O2•-, •NO, and ONOO- in vitro and in vivo and provides neuroprotection against ischemic stroke. In vitro experiments showed that pre-incubation with the Co-Fe3O4 nanozyme could prevent neurotoxicity and neuroinflammation induced by H2O2 or lipopolysaccharide, respectively, in HT22 cells. After intravenous administration, the Co-Fe3O4 nanozyme showed no signs of toxicity in peripheral organs of C57BL/6J mice, even after prolonged delivery for 4 weeks. In permanent photothrombotic stroke model and transient middle cerebral artery occlusion stroke model, the Co-Fe3O4 nanozyme specifically accumulated in the infarct rim at 72 h post-stroke and was endocytosed by neurons, astrocytes, microglia, and endothelial cells. Importantly, the Co-Fe3O4 nanozyme delivery reduced the infarct volume in both stroke models. The observation that the Co-Fe3O4 nanozyme was efficacious in two well-characterized ischemic stroke models provides strong evidence that it represents a powerful tool for targeting oxidative and nitrosative stress in the ischemic brain.


Assuntos
Sequestradores de Radicais Livres/uso terapêutico , AVC Isquêmico/tratamento farmacológico , Nanopartículas de Magnetita/uso terapêutico , Fármacos Neuroprotetores/uso terapêutico , Espécies Reativas de Nitrogênio/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Animais , Catálise , Linhagem Celular , Cobalto/química , Cobalto/toxicidade , Sequestradores de Radicais Livres/química , Sequestradores de Radicais Livres/toxicidade , Lipopolissacarídeos , Nanopartículas de Magnetita/química , Nanopartículas de Magnetita/toxicidade , Masculino , Camundongos Endogâmicos C57BL , Doenças Neuroinflamatórias/induzido quimicamente , Doenças Neuroinflamatórias/tratamento farmacológico , Neuroproteção/efeitos dos fármacos , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/toxicidade , Oxirredução , Espécies Reativas de Nitrogênio/química , Espécies Reativas de Oxigênio/química
8.
Wound Repair Regen ; 29(6): 1006-1016, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34448508

RESUMO

Prolonged skin exposure to ultraviolet radiation can lead to development of several acute and chronic diseases, with UVA exposure considered a primary cause of dermal photodamage. We prepared a wild ginseng adventitious root extract (ARE) that could alleviate UVA irradiation-induced NIH-3T3 cell viability decline. After employing a series of purification methods to isolate main active components of ARE, adventitious root protein mixture (ARP) was identified then tested for protective effects against UVA irradiation-induced NIH-3T3 cell damage. The results showed that ARP treatment significantly reduced UVA-induced cell viability decline and confirmed that the active constituent of ARP was the protein, since proteolytic hydrolysis and heat treatment each eliminated ARP protective activity. Moreover, ARP treatment markedly inhibited UVA-induced apoptosis, cell cycle arrest and DNA fragmentation, while also significantly reversing UVA effects (elevated Bax levels, reduced Bcl-2 expression) by reducing Bax levels and increasing Bcl-2 expression. Mechanistically, ARP promoted Akt phosphorylation regardless of UVA exposure, thus confirming ARP resistance to inactivation by UVA light. Notably, in the presence of Akt inhibitor SC0227, ARP could no longer counteract UVA-induced cell viability decline and DNA fragmentation. Additionally, our results demonstrated that ARP treatment protected UVA-irradiated NIH-3T3 cells by preventing UVA-induced reduction of collagen-I expression. Taken together, these results suggest that ARP treatment of NIH-3T3 cells effectively mitigated UVA-induced cell viability decline by activating intracellular Akt to reduce UVA-induced DNA damage, leading to reduced rates of apoptosis and cell cycle arrest after UVA exposure and restoring collagen expression to normal levels.


Assuntos
Panax , Raios Ultravioleta , Animais , Apoptose , Camundongos , Células NIH 3T3 , Proteínas Proto-Oncogênicas c-akt , Raios Ultravioleta/efeitos adversos , Cicatrização
10.
Biomed Pharmacother ; 115: 108840, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31048189

RESUMO

BACKGROUND AND AIMS: Hirudo is an important Chinese medicine that has been widely used in patients with thrombosis-related diseases. We aimed to evaluate the protective effect and potential mechanism of Hirudo extract (HE) on the process of atherosclerosis (AS) as well as identify its active components in the lipopolysaccharide (LPS) - or oxidized low-density lipoprotein (ox-LDL)-induced cell models. METHODS: After treatment, adhesion molecules and pro-inflammatory cytokines induced by LPS were examined by qPCR and ELISA. ROS production, cell apoptosis, and lipid accumulation in ox-LDL-induced cells were analyzed by flow cytometry, qPCR, western blotting, and immunofluorescence staining. In addition, the main active components of HE were identified and analyzed for preventing the progression of AS. RESULTS: In this study, we found that HE pretreatment for 48 h significantly inhibited monocyte adhesion and reduced the levels of adhesion factors (ICAM-1 and VCAM-1) and pro-inflammatory factors (IL-6 and TNF-α) in LPS-induced endothelial cells. Moreover, HE attenuated ox-LDL-induced ROS accumulation and apoptosis in macrophage cells via mitochondrial apoptotic pathways. Additionally, HE pretreatment effectively inhibited cholesterol uptake and increased cholesterol efflux by regulating the LOX-1/LXR-α/ABCA1 pathway. Importantly, the polypeptides from HE (PP) with a molecular weight < 10,000 Da accounted for about 62.9% of the total amount of polypeptides, which in turn may be active components of HE that are responsible for inhibiting inflammation, foam cell formation and apoptosis. CONCLUSION: PP from HE potently inhibits endothelial cell inflammatory injury and macrophage foam cell formation and apoptosis by regulating the LOX-1/LXR-α/ABCA1 pathway, thereby providing additional support to the beneficial effects of HE in preventing AS.


Assuntos
Células Espumosas/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Sanguessugas/química , Macrófagos/efeitos dos fármacos , Peptídeos/farmacologia , Receptores Depuradores Classe E/metabolismo , Transportador 1 de Cassete de Ligação de ATP/genética , Transportador 1 de Cassete de Ligação de ATP/metabolismo , Animais , Adesão Celular/efeitos dos fármacos , Colesterol/metabolismo , Relação Dose-Resposta a Droga , Regulação da Expressão Gênica/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Lipopolissacarídeos/administração & dosagem , Lipopolissacarídeos/toxicidade , Lipoproteínas LDL/administração & dosagem , Lipoproteínas LDL/toxicidade , Receptores X do Fígado/genética , Receptores X do Fígado/metabolismo , Camundongos , Peptídeos/química , Células RAW 264.7 , Espécies Reativas de Oxigênio , Receptores Depuradores Classe E/genética , Células THP-1
11.
Int J Mol Sci ; 16(9): 21153-76, 2015 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-26370957

RESUMO

Eukaryotic cells possess several mechanisms to adapt to endoplasmic reticulum (ER) stress and thereby survive. ER stress activates a set of signaling pathways collectively termed as the unfolded protein response (UPR). We previously reported that Bone morphogenetic protein 2 (BMP2) mediates mild ER stress and activates UPR signal molecules in chondrogenesis. The mammalian UPR protects the cell against the stress of misfolded proteins in the endoplasmic reticulum. Failure to adapt to ER stress causes the UPR to trigger apoptosis. Glucose regulated protein 78 (GRP78), as an important molecular chaperone in UPR signaling pathways, is responsible for binding to misfolded or unfolded protein during ER stress. However the influence on GRP78 in BMP2-induced chondrocyte differentiation has not yet been elucidated and the molecular mechanism underlyng these processes remain unexplored. Herein we demonstrate that overexpression of GRP78 enhanced cell proliferation in chondrocyte development with G1 phase advance, S phase increasing and G2-M phase transition. Furthermore, overexpression of GRP78 inhibited ER stress-mediated apoptosis and then reduced apoptosis in chondrogenesis induced by BMP2, as assayed by cleaved caspase3, caspase12, C/EBP homologous protein (CHOP/DDIT3/GADD153), p-JNK (phosphorylated c-Jun N-terminal kinase) expression during the course of chondrocyte differentiation by Western blot. In addition, flow cytometry (FCM) assay, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end-labeling (TUNEL) assay and immune-histochemistry analysis also proved this result in vitro and in vivo. It was demonstrated that GRP78 knockdown via siRNA activated the ER stress-specific caspase cascade in developing chondrocyte tissue. Collectively, these findings reveal a novel critical role of GRP78 in regulating ER stress-mediated apoptosis in cartilage development and the molecular mechanisms involved.


Assuntos
Apoptose/genética , Condrogênese/genética , Proteínas de Choque Térmico/genética , Animais , Proteína Morfogenética Óssea 2/metabolismo , Técnicas de Cultura de Células , Diferenciação Celular/genética , Linhagem Celular , Proliferação de Células/genética , Condrócitos/citologia , Condrócitos/metabolismo , Chaperona BiP do Retículo Endoplasmático , Estresse do Retículo Endoplasmático/genética , Endorribonucleases/metabolismo , Expressão Gênica , Lâmina de Crescimento/embriologia , Lâmina de Crescimento/metabolismo , Proteínas de Choque Térmico/metabolismo , Camundongos , Proteínas Serina-Treonina Quinases/metabolismo , Interferência de RNA , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Interferente Pequeno , Transdução de Sinais , Técnicas de Cultura de Tecidos , Resposta a Proteínas não Dobradas/genética
12.
Cell Signal ; 26(9): 1998-2007, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24863879

RESUMO

Bone morphogenetic protein 2(BMP2) is known to activate unfolded protein response (UPR) signal molecules in chondrogenesis. Inositol-requiring enzyme-1α (IRE1α),as one of three unfolded protein sensors in UPR signaling pathways, can be activated during ER stress. However, the influence on IRE1α in chondrocyte differentiation has not yet been elucidated. Here we present evidence demonstrating that overexpression of IRE1α inhibits chondrocyte differentiation, as revealed by reduced expression of collagen II (ColII), Sox9, collagen X (ColX), matrix metalloproteinase 13 (MMP-13), Indian hedgehog (IHH), Runx2 and enhanced expression of parathyroid hormone-related peptide (PTHrP). Furthermore, IRE1α-mediated inhibition of chondrogenesis depends on its enzymatic activity, since its point mutant lacking enzymatic activity completely loses this activity. The RNase and Kinase domains of IRE1α C-terminal are necessary for its full enzymatic activity and inhibition of chondrocyte differentiation. Mechanism studies demonstrate that granulin-epithelin precursor(GEP), a growth factor known to stimulate chondrogenesis, induced IRE1α expression in chondrogenesis. The expression of IRE1α is depended on GEP signaling, and IRE1α expression is hardly detectable in GEP(-/-) embryos. In addition, IRE1α inhibits GEP-mediated chondrocyte differentiation as a negative regulator. Altered expression of IRE1α in chondrocyte hypertrophy was accompanied by altered levels of IHH and PTHrP. Collectively, IRE1α may be a novel regulator of chondrocyte differentiation by 1) inhibition GEP-mediated chondrocyte differentiation as a negative regulator; 2) promoting IHH/PTHrP signaling.


Assuntos
Diferenciação Celular , Condrócitos/citologia , Condrócitos/enzimologia , Endorribonucleases/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Animais , Proteína Morfogenética Óssea 2/farmacologia , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Condrogênese/efeitos dos fármacos , Endorribonucleases/antagonistas & inibidores , Endorribonucleases/genética , Feminino , Peptídeos e Proteínas de Sinalização Intercelular/deficiência , Peptídeos e Proteínas de Sinalização Intercelular/genética , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Células-Tronco Mesenquimais/citologia , Camundongos , Camundongos Endogâmicos BALB C , Progranulinas , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/genética , Interferência de RNA , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/metabolismo , Transdução de Sinais/efeitos dos fármacos
13.
J Biol Chem ; 287(41): 34500-13, 2012 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-22865880

RESUMO

BMP2 (bone morphogenetic protein 2) is known to activate unfolded protein response signaling molecules, including XBP1S and ATF6. However, the influence on XBP1S and ATF6 in BMP2-induced chondrocyte differentiation has not yet been elucidated. In this study, we demonstrate that BMP2 mediates mild endoplasmic reticulum stress-activated ATF6 and directly regulates XBP1S splicing in the course of chondrogenesis. XBP1S is differentially expressed during BMP2-stimulated chondrocyte differentiation and exhibits prominent expression in growth plate chondrocytes. This expression is probably due to the activation of the XBP1 gene by ATF6 and splicing by IRE1a. ATF6 directly binds to the 5'-flanking regulatory region of the XBP1 gene at its consensus binding elements. Overexpression of XBP1S accelerates chondrocyte hypertrophy, as revealed by enhanced expression of type II collagen, type X collagen, and RUNX2; however, knockdown of XBP1S via the RNAi approach abolishes hypertrophic chondrocyte differentiation. In addition, XBP1S associates with RUNX2 and enhances RUNX2-induced chondrocyte hypertrophy. Altered expression of XBP1S in chondrocyte hypertrophy was accompanied by altered levels of IHH (Indian hedgehog) and PTHrP (parathyroid hormone-related peptide). Collectively, XBP1S may be a novel regulator of hypertrophic chondrocyte differentiation by 1) acting as a cofactor of RUNX2 and 2) affecting IHH/PTHrP signaling.


Assuntos
Diferenciação Celular , Condrócitos/metabolismo , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Proteínas de Ligação a DNA/metabolismo , Fatores de Transcrição/metabolismo , Fator 6 Ativador da Transcrição/genética , Fator 6 Ativador da Transcrição/metabolismo , Animais , Proteína Morfogenética Óssea 2/genética , Proteína Morfogenética Óssea 2/metabolismo , Linhagem Celular , Condrócitos/patologia , Colágeno Tipo II/genética , Colágeno Tipo II/metabolismo , Subunidade alfa 1 de Fator de Ligação ao Core/genética , Proteínas de Ligação a DNA/genética , Feminino , Regulação da Expressão Gênica/genética , Técnicas de Silenciamento de Genes , Lâmina de Crescimento/metabolismo , Lâmina de Crescimento/patologia , Proteínas Hedgehog/genética , Proteínas Hedgehog/metabolismo , Hipertrofia , Camundongos , Camundongos Endogâmicos BALB C , Proteína Relacionada ao Hormônio Paratireóideo/genética , Proteína Relacionada ao Hormônio Paratireóideo/metabolismo , Fatores de Transcrição de Fator Regulador X , Fatores de Transcrição/genética , Proteína 1 de Ligação a X-Box
14.
Histochem Cell Biol ; 138(3): 447-60, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22669460

RESUMO

The mammalian unfolded protein response (UPR) protects the cell against the stress of misfolded proteins in the endoplasmic reticulum (ER), and the transcription factor X-box binding protein 1 spliced (XBP1S), a regulator of the UPR, is known to be important for ER stress (ERS)-mediated apoptosis and cell growth, but the molecular mechanism underlying these processes remains unexplored. Here, we report that knockdown of XBP1S by an siRNA silencing approach increased the expression of ERS-associated molecules. The overexpression of XBP1S stimulated, whereas its knockdown inhibited, cell proliferation in chondrocytes and chondrosarcoma cells; in addition, overexpression of XBP1S inhibited, while its repression enhanced, ERS-mediated apoptosis in chondrocytes and chondrosarcoma cells. Furthermore, XBP1S-mediated inhibition of apoptosis in response to ERS is through the Erk1/2 signaling pathway and down-regulation CHOP transcription factor. CHOP is one of the key downstream molecules known to be involved in ERS-mediated apoptosis. Collectively, these findings reveal a novel critical role of XBP1S in ERS-mediated apoptosis and the molecular mechanisms involved.


Assuntos
Apoptose , Proteínas de Ligação a DNA/genética , Estresse do Retículo Endoplasmático , Sistema de Sinalização das MAP Quinases , Fator de Transcrição CHOP/metabolismo , Fatores de Transcrição/genética , Proliferação de Células , Proteínas de Ligação a DNA/metabolismo , Regulação para Baixo , Retículo Endoplasmático/metabolismo , Células HEK293 , Humanos , Splicing de RNA , RNA Interferente Pequeno/metabolismo , Fatores de Transcrição de Fator Regulador X , Fator de Transcrição CHOP/genética , Fatores de Transcrição/metabolismo , Resposta a Proteínas não Dobradas , Proteína 1 de Ligação a X-Box
15.
Mol Cell Biochem ; 365(1-2): 99-108, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22314839

RESUMO

The mammalian unfolded protein response (UPR) protects the cell against the stress of misfolded proteins in the endoplasmic reticulum (ER). Failure to adapt to ER stress causes the UPR to trigger apoptosis. Inositol-requiring enzyme-1a (IRE1a), as one of three unfolded protein sensors in UPR signaling pathways, senses ER unfolded proteins through an ER lumenal domain that becomes oligomerized during ER stress. It is known to be important for ER stress-mediated apoptosis and cell growth, but the exact molecular mechanism underlying these processes remains unexplored. In this study, we report that knockdown of IRE1a by an siRNA silencing approach enhanced, whereas its overexpression inhibited, cell proliferation in Hepatoma cells. Besides, overexpression of IRE1a induced, while its repression inhibited, ER stress-mediated apoptosis in Hepatomas cells. Furthermore, we found that overexpressed IRE1a can down-regulate Polo-like kinase 1(PLK1) from mRNA and protein two levels. IRE1a-mediated induction of apoptosis and inhibition of proliferation in response to ER stress is through downregulation PLK1, an early trigger for G2/M transition known to be participated in regulating cell proliferation and cell apoptosis. Collectively, these findings reveal a novel critical role of IRE1a in ER stress-mediated apoptosis and the molecular mechanisms involved. IRE1a may be a useful molecular target for the development of novel predictive and therapeutic strategies in cancer.


Assuntos
Apoptose , Proteínas de Ciclo Celular/metabolismo , Proliferação de Células , Estresse do Retículo Endoplasmático , Endorribonucleases/fisiologia , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Serina-Treonina Quinases/fisiologia , Proteínas Proto-Oncogênicas/metabolismo , Caspase 3/metabolismo , Pontos de Checagem do Ciclo Celular , Proteínas de Ciclo Celular/genética , Proteínas de Ligação a DNA/metabolismo , Regulação para Baixo , Endorribonucleases/genética , Endorribonucleases/metabolismo , Regulação Enzimológica da Expressão Gênica , Técnicas de Silenciamento de Genes , Células Hep G2 , Humanos , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Proto-Oncogênicas/genética , Interferência de RNA , Fatores de Transcrição de Fator Regulador X , Transdução de Sinais , Fatores de Transcrição/metabolismo , Quinase 1 Polo-Like
16.
J Chem Phys ; 134(21): 214118, 2011 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-21663355

RESUMO

The multi-reference (MR), general model space (GMS), state-universal (SU), coupled-cluster (CC) method with singles and doubles (GMS-SU-CCSD), as well as its triple-corrected versions GMS-SU-CCSD(T), are employed to assess their ability to describe low-lying excited states of various molecules, with an emphasis on a simultaneous handling of several states of the same symmetry species. A special attention is given to the role of the so-called C-conditions that account for non-vanishing internal cluster amplitudes when relying on an incomplete GMS, as well as to the choice of suitable model spaces and a perturbative account of secondary triples. The ambiguities arising when using large basis sets are also pointed out. To achieve a general assessment of the potential of the GMS-type SU-CC approaches, the vertical excitation energies of several species, including the challenging BN diatomic as well as larger systems, namely formaldehyde, trans-butadiene, formamide, and benzene are considered. These results are compared with those provided by the equation-of-motion EOM-CCSD method and, whenever available, the density functional theory results and experimental data. These comparisons clearly demonstrate the usefulness of GMS-type MR-CC approaches.

17.
J Chem Phys ; 134(7): 074301, 2011 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-21341838

RESUMO

The potential energy surfaces (PESs) for both the ground and the excited electronic states of the C(2)B radical are investigated using various multireference (MR) coupled-cluster (CC) approaches. In the ground state case we employ the reduced MR (RMR) CC approach with singles (S) and doubles (D), the RMR CCSD method, as well as its RMR CCSD(T) version corrected for secondary triples, relying on various model spaces and basis sets. The reliability of this approach is also tested against the benchmark full configuration interaction results obtained for a small Dunning-Hay (DH) basis set. The results imply a clear preference for a cyclic structure which, however, breaks the C(2v) symmetry. This symmetry breaking manifests itself strongly at the level of the independent particle model, as represented by the restricted open-shell Hartree-Fock approximation, but the tendency toward symmetry breaking diminishes with the increasing size of the basis set employed as well as with the enhanced account of the correlation effects. It is likely to disappear in the complete basis set limit. The general model space CCSD method is then used to compute vertical excitation energies for a number of excited states as well as the cuts of the PES as the boron atom moves around the C(2) fragment. These results also explain why no symmetry breaking is found when relying on a spin contaminated unrestricted Hartree-Fock reference, as in the UMP2 method.

18.
J Chem Phys ; 133(18): 184106, 2010 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-21073212

RESUMO

The concept of C-conditions, originally introduced in the framework of the multireference (MR), general-model-space (GMS), state-universal (SU), coupled-cluster (CC) approach with singles and doubles (GMS-SU-CCSD) to account for the internal amplitudes that vanish in the case of a complete model space, is applied to a state-selective or state-specific Mukherjee MR-CC method (MkCCSD). In contrast to the existing applications, the emphasis is on the description of excited states, particularly those belonging to the same symmetry species. The applicability of the C-conditions in all MR-SU-CC approaches is emphasized. Convergence problems encountered in the MkCCSD method when handling higher-lying states are pointed out. The performance of the GMS-SU-CCSD and MkCCSD methods is illustrated by considering low-lying vertical excitation energies of the ethylene molecule and para-benzyne diradical. A comparison with the equation-of-motion CCSD results, as well as with the available experimental data and recent multireference configuration interaction theoretical results, is also provided.

19.
J Chem Phys ; 133(2): 024102, 2010 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-20632743

RESUMO

Multireference (MR), general-model-space (GMS), state-universal (SU) coupled-cluster (CC) method that considers singly (S) and doubly (D) excited cluster amplitudes relative to the reference configurations spanning the model space (GMS SU CCSD), as well as its externally corrected (ec) version (N,M)-CCSD that employs N-reference MR CISD as an external source of higher-than-pair cluster amplitudes in a M-reference GMS CCSD, are employed to investigate low-lying states of the water molecule. The emphasis is on a generation of several low lying states belonging to the same symmetry species. Cuts of the potential energy surface (PES) corresponding to the breaking of a single OH bond and leading to the OH+H fragments, as well as the simultaneous breaking of both bonds into the O+2H are considered. Relying on a simple ab initio model that enables a comparison with the exact full configuration interaction energies, the performance of the GMS-based methods is assessed in the whole relevant range of internuclear separations. It is shown that the ec (N,M)-CCSD version provides best results for both the singlet and the triplet states considered. The same cuts of the PES are then explored using a realistic aug-cc-pVTZ basis set. For triplets, the use of high-spin (M(S)=1) references is to be preferred.

20.
J Chem Phys ; 132(11): 114103, 2010 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-20331277

RESUMO

The reduced multireference (RMR) coupled-cluster (CC) method with singles and doubles (RMR CCSD) that exploits a modest size MR CISD wave function as an external source for a small subset of the most important (primary) triples and quadruples to account for quasidegeneracy due to a MR nature of the states considered, as well as its RMR CCSD(T) version corrected for the secondary triples, are employed to compute fundamental vibrational frequencies for the para- and metabenzene diradicals. A comparison is made with the available experimental data and with other methods, namely, the state selective or Mukherjee CCSD and completely renormalized, size-extensive version of CCSD(T), the so-called CR-CC(2,3), methods. Both the restricted Hartree-Fock and multiconfiguration self-consistent-field (MCSCF) molecular orbitals (MOs) are employed. The four-reference RMR CCSD using MCSCF MOs gives particularly satisfactory results. The breakdown of CCSD(T) and shortcomings of some other approaches are pointed out and the role of invariance with respect to MO rotation is analyzed. Correlation with triplet-singlet splittings is also pointed out.


Assuntos
Derivados de Benzeno/química , Simulação por Computador , Radicais Livres/química , Teoria Quântica , Rotação , Estereoisomerismo , Vibração
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