Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
2.
Hepatology ; 2023 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-37820269

RESUMO

BACKGROUND AND AIMS: DILI accounts for more than half of acute liver failure cases in the United States and is a major health care issue for the public worldwide. As investigative toxicology is playing an evolving role in the pharmaceutical industry, mechanistic insights into drug hepatotoxicity can facilitate drug development and clinical medication. METHODS: By integrating multisource datasets including gene expression profiles of rat livers from open TG-GATE database and DrugMatrix, drug labels from FDA Liver Toxicity Knowledge Base, and clinical reports from LiverTox, and with the employment of bioinformatic and computational tools, this study developed an approach to characterize and predict DILI based on the molecular understanding of the processes (toxicity pathways). RESULTS: A panel of 11 pathways widely covering biological processes and stress responses was established using a training set of six positive and one negative DILI drugs from open TG-GATEs. An entropy weight method-based model was developed to weight responsive genes within a pathway, and an interpretable machine-learning (ML) model XGBoot-SHAP was trained to rank the importance of pathways to the panel activity. The panel activity was proven to differentiate between injured and noninjured sample points and characterize DILI manifestation using six training drugs. Next, the model was tested using an additional 89 drugs (61 positives + 28 negatives), and a precision of 86% and higher can be achieved. CONCLUSIONS: This study provides a novel approach to mechanisms-driven prediction modeling, as well as big data integration for insights into pharmacology and other human biology areas.

3.
Front Behav Neurosci ; 16: 976155, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36212192

RESUMO

Few studies have examined the role of cognitive control in processing ambiguity, let alone the roles of different components of cognitive control. In the current study, the English (L2) Sentence Processing Task and a series of cognitive control tasks were administered among 111 young adult Chinese-English bilinguals to investigate the influence of different components of cognitive control on garden path sentence comprehension, with other factors such as age, socio-economic status, and language proficiency strictly matched. Data analysis results showed a significant garden path effect on response times (RTs) and accuracy among all the participants. The results of independent t-test analyses revealed that the high working memory (WM) group was faster in ambiguity resolution, and so was the high monitoring group. However, there were no differences between the high and low inhibition and shifting groups in ambiguity resolution. These findings reveal that only certain aspects of cognitive control influence garden path sentence comprehension.

4.
Nutrients ; 14(16)2022 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-36014912

RESUMO

The coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is spreading rapidly around the world and has led to millions of infections and deaths. Growing evidence indicates that iron metabolism is associated with COVID-19 progression, and iron-related biomarkers have great potential for detecting these diseases. However, the results of previous studies are conflicting, and there is not consistent numerical magnitude relationship between those biomarkers and COVID-19. Thereby, we aimed to integrate the results of current studies and to further explore their relationships through a meta-analysis. We searched peer-reviewed literature in PubMed, Scopus and Web of Science up to 31 May 2022. A random effects model was used for pooling standard mean difference (SMD) and the calculation of the corresponding 95% confidence interval (CI). I2 was used to evaluate heterogeneity among studies. A total of 72 eligible articles were included in the meta-analysis. It was found that the ferritin levels of patients increased with the severity of the disease, whereas their serum iron levels and hemoglobin levels showed opposite trends. In addition, non-survivors had higher ferritin levels (SMD (95%CI): 1.121 (0.854, 1.388); Z = 8.22 p for Z < 0.001; I2 = 95.7%, p for I2 < 0.001), lower serum iron levels (SMD (95%CI): −0.483 (−0.597, −0.368), Z = 8.27, p for Z < 0.001; I2 = 0.9%, p for I2 =0.423) and significantly lower TIBC levels (SMD (95%CI): −0.612 (−0.900, −0.324), Z = 4.16, p for Z < 0.001; I2 = 71%, p for I2 = 0.016) than survivors. This meta-analysis demonstrates that ferritin, serum iron, hemoglobin and total iron banding capacity (TIBC) levels are strongly associated with the risk, severity and mortality of COVID-19, providing strong evidence for their potential in predicting disease occurrence and progression.


Assuntos
COVID-19 , SARS-CoV-2 , Biomarcadores , COVID-19/mortalidade , Ferritinas , Hemoglobinas/metabolismo , Humanos , Ferro
5.
Artigo em Inglês | MEDLINE | ID: mdl-35627526

RESUMO

With the increasingly prominent energy and environmental problems, environmental innovation has become a critical path to achieving the goal of coordinating economic development and environmental protection fundamentally. This study aims to examine the impacts of executive overconfidence on environmental innovation and the mediating role of digital transformation. We conduct empirical tests based on the panel data of Chinese publicly listed enterprises during the period of 2007-2019. The results exhibit that (a) executive overconfidence can significantly promote environmental technology innovation but has no obvious effect on environmental management innovation; (b) executive overconfidence can significantly enhance digital transformation, and, accordingly, digital transformation can significantly promote environmental technology innovation and environmental management innovation; (c) industry competition and economic policy uncertainty can enhance the positive effect of executive overconfidence on digital transformation; and (d) a firms' asset size can enhance the impact of digital transformation on environmental technology innovation; internal control positively moderates the impact of digital transformation on environmental technology innovation and negatively moderates the impact on environmental management innovation. This study not only breaks the stereotype about overconfidence and confirms its positive impact on digital transformation and environmental innovation but also provides insights for enterprises to improve environmental innovation through digital transformation.


Assuntos
Desenvolvimento Econômico , Invenções , Conservação dos Recursos Naturais , Indústrias
6.
Artigo em Inglês | MEDLINE | ID: mdl-35329270

RESUMO

Although a firm's exposure to air pollution-related risk has become an important factor that creditors cannot ignore in the procedure of lending decision making with the aggravation of air pollution, empirical evidence on whether and how air pollution affects the cost of debt has been relatively scarce. Employing a series of Chinese listed firms from the main board of the Shanghai and Shenzhen Stock Exchanges covering 2014 to 2018, our research responds to this research gap by exploring how air pollution-induced environmental violation risk affects the cost of debt by constructing an assessment system of firms' environmental violation risk. The results shed light on an issue that firms exposed to higher concentrations of air pollution may suffer a higher environmental violation risk, resulting in a higher debt cost. In addition, a further analysis shows that environmental regulatory pressure and heavily polluting firms enhance the influence of air pollution on the cost of debt, while state-owned firms and firms' economic contributions weaken the influence of air pollution on the cost of debt. Our research is conducive to highlighting not only the importance of environmental governance for mitigating the cost of debt to the firms exposed to air pollution, but also its importance to creditors exposed to their clients' environmental violation risk and default risk.


Assuntos
Poluição do Ar , Política Ambiental , Poluição do Ar/efeitos adversos , China , Conservação dos Recursos Naturais , Poluição Ambiental/efeitos adversos , Humanos
7.
Front Psychol ; 11: 94, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32063879

RESUMO

Previous studies have suggested a bilingual advantage in cognitive control as a result of the bilinguals' language experience. However, the results are controversial as there are various factors (language proficiency, SES, culture, and intelligence, etc.) affecting cognitive control. In the current study, after between-group comparisons, we adopted a within-group approach by multiple regressions to investigate whether the performance by 10-to-75-year-old participants (N = 91) of tasks measuring inhibition, monitoring, and mental set shifting could be predicted by bilingualism, or demographic factors, or both. The results of multiple stepwise regression analyses showed that L2 proficiency was a significant predictor for conflict monitoring and inhibition, education and age were significant predictors for mental set shifting, and SES was a minor predictor for inhibition. These findings provide evidence that cognitive control is affected by both bilingualism and demographic factors. Future studies are encouraged to further identify the relationship between bilingualism and cognitive control from specific bilingual experience.

8.
Emerg Microbes Infect ; 7(1): 205, 2018 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-30518755

RESUMO

Enterovirus A71 (EV-A71) is a major etiological agent of human hand, foot and mouth disease, and it can cause severe neurological complications. Although several genotypes of EV-A71 strains are prevalent in different regions of the world, the genotype C4 has circulated in mainland China for more than 20 years. The pathogenicity of different EV-A71 clinical isolates varies and needs to be explored. In this study, hSCARB2 knock-in mice (N = 181) with a wide range of ages were tested for their susceptibility to two EV-A71 strains with the subgenotypes C4 and C2, and two infection routes (intracranial and venous) were compared. The clinical manifestations and pathology and their relationship to the measured viral loads in different tissues were monitored. We observed that 3 weeks is a crucial age, as mice younger than 3-week-old that were infected became extremely ill. However, mice older than 3 weeks displayed diverse clinical symptoms. Significant differences were observed in the pathogenicity of the two strains with respect to clinical signs, disease incidence, survival rate, and body weight change. We concluded that hSCARB2 knock-in mice are a sensitive model for investigating the clinical outcomes resulting from infection by different EV-A71 strains. The intracranial infection model appears to be suitable for evaluating EV-A71 neurovirulence, whereas the venous infection model is appropriate for studying the pathogenicity of EV-A71.


Assuntos
Encéfalo/virologia , Modelos Animais de Doenças , Enterovirus Humano A/patogenicidade , Infecções por Enterovirus/virologia , Proteínas de Membrana Lisossomal/genética , Receptores Depuradores/genética , Administração Intravenosa , Fatores Etários , Animais , Antígenos Virais/genética , Enterovirus Humano A/genética , Infecções por Enterovirus/sangue , Técnicas de Introdução de Genes , Genótipo , Humanos , Camundongos , Crânio/virologia , Carga Viral , Virulência
9.
BMC Cancer ; 17(1): 545, 2017 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-28807016

RESUMO

BACKGROUND: Real-time polymerase chain reaction (PCR) has become an increasingly important technique for gene expression profiling because it can provide insights into complex biological and pathological processes and be used to predict disease or treatment outcomes. Although normalized data are necessary for an accurate estimation of mRNA expression levels, several pieces of evidence suggest that the expression of so-called housekeeping genes is not stable. This study aimed to validate reference genes for the normalization of real-time PCR in an N-methyl-N-nitrosourea (MNU)-induced T-cell lymphoma mouse model. METHODS: T-cell lymphomas were generated in p53-deficient mice by treatment with 37.5 mg/kg MNU. Thymus and spleen were identified as the primary target organs with the highest incidences of lymphomas. We analyzed the RNA expression levels of eight potential endogenous reference genes (Gapdh, Rn18s, Actb, Hprt, B2M, Rplp0, Gusb, Ctbp1). The expression stabilities of these reference genes were tested at different time points after MNU treatment using geNorm and NormFinder algorithms. RESULTS: A total of 65% of MNU-treated mice developed T-cell lymphomas, with the spleen and thymus as the major target organs. All candidate reference genes were amplified efficiently by quantitative reverse-transcription polymerase chain reaction (RT-qPCR). Gene stability evaluation after MNU treatment and during lymphomagenesis revealed that Ctbp1 and Rplp0 were the most stably expressed genes in the thymus and spleen, respectively. RT-PCR of thymus RNA using two additional sets of primer confirmed that Ctbp1 was the most stable of all the candidate reference genes. CONCLUSIONS: We provided suitable endogenous controls for gene expression studies in the T-cell lymphoma model.


Assuntos
Oxirredutases do Álcool/genética , Proteínas de Ligação a DNA/genética , Regulação Neoplásica da Expressão Gênica , Genes Essenciais , Linfoma de Células T/genética , Metilnitrosoureia/toxicidade , Reação em Cadeia da Polimerase em Tempo Real/métodos , Proteínas Ribossômicas/genética , Animais , Modelos Animais de Doenças , Linfoma de Células T/tratamento farmacológico , Linfoma de Células T/metabolismo , Camundongos , Camundongos Knockout , Proteína Supressora de Tumor p53/genética
10.
Sci Rep ; 7(1): 3597, 2017 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-28620164

RESUMO

As concerns increase about adenovirus type 5 (Ad5) being a safe gene transfer vector, it is important to evaluate its distribution, residence time, and possible toxicity in immunodeficient populations. To characterize the potential risk associated with different Ad5 vector delivery modes, we used immunocompetent and immunodeficient Rag2 -/- animals to establish mouse and rat models that could be monitored with bioluminescent imaging following intramuscular or intravascular infection with an engineered replication-incompetent Ad5 virus carrying the firefly luciferase gene (Ad5-Fluc). The Ad5 vector was less well-tolerated by Rag2 -/- animals than by wildtype ones, with delayed residence time, wider virus dissemination, less weight gain, and relatively severe pathological changes. In intravascularly Ad5-Fluc-infected Rag2 -/- mice, systemic virus dissemination extended from the abdomen to the limbs and head on day 9 post-infection. Additionally, significant increases in plasma TNF-α and IFN-γ, which may be important factors in the heightened immunopathology in the liver and brain, were detected in the Rag2 -/- mice 30 days after intravascular delivery. The Ad5 vector was better tolerated after intramuscular delivery than after intravascular delivery. Ad5-Fluc/Rag2 -/- mice and rats can be used as reliable models of an immunodeficient population in which to evaluate the safety of Ad5-vectored vaccines or gene therapy products.


Assuntos
Adenovírus Humanos/genética , Portadores de Fármacos/farmacocinética , Vetores Genéticos/farmacocinética , Medições Luminescentes , Administração Intravenosa , Animais , Portadores de Fármacos/administração & dosagem , Genes Reporter , Vetores Genéticos/administração & dosagem , Injeções Intramusculares , Luciferases de Vaga-Lume/análise , Camundongos , Ratos , Coloração e Rotulagem , Fatores de Tempo , Imagem Corporal Total
11.
Mater Sci Eng C Mater Biol Appl ; 76: 1136-1145, 2017 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-28482478

RESUMO

The inclusion complexation behavior, characterization, and inclusion mode of podophyllotoxin (POD) with hydroxypropyl-ß-cyclodextrin (HPßCD) were investigated in both solution and the solid state by means of XRD, DSC, SEM, 1H and 2D NMR and UV-vis spectroscopy. The results showed that the water solubility and thermal stability of POD were obviously increased in the inclusion complex with HPßCD. The cytotoxicity of POD/HPßCD inclusion complex against all the human tumor cell lines investigated still remains. This satisfactory water solubility and high thermal stability of the POD/HPßCD complex will be potentially useful for their application as herbal medicines or healthcare products.


Assuntos
2-Hidroxipropil-beta-Ciclodextrina/química , Podofilotoxina/química , Varredura Diferencial de Calorimetria , Linhagem Celular Tumoral , Humanos , Solubilidade
12.
Sci Rep ; 7: 45552, 2017 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-28358050

RESUMO

Passive immunotherapy with monoclonal antibodies (mAbs) is an efficacious treatment for Ebola virus (EBOV) infections in animal models and humans. Understanding what constitutes a protective response is critical for the development of novel therapeutic strategies. We generated an EBOV-glycoprotein-pseudotyped Human immunodeficiency virus to develop sensitive neutralizing and antibody-dependent cellular cytotoxicity (ADCC) assays as well as a bioluminescent-imaging-based mouse infection model that does not require biosafety level 4 containment. The in vivo treatment efficiencies of three novel anti-EBOV mAbs at 12 h post-infection correlated with their in vitro anti-EBOV ADCC activities, without neutralizing activity. When they were treated with these mAbs, natural killer cell (NK)-deficient mice had lower viral clearance than WT mice, indicating that the anti-EBOV mechanism of the ADCC activity of these mAbs is predominantly mediated by NK cells. One potent anti-EBOV mAb (M318) displayed unprecedented neutralizing and ADCC activities (neutralization IC50, 0.018 µg/ml; ADCC EC50, 0.095 µg/ml). These results have important implications for the efficacy of antiviral drugs and vaccines as well as for pathogenicity studies of EBOV.


Assuntos
Anticorpos Monoclonais/imunologia , Citotoxicidade Celular Dependente de Anticorpos , Doença pelo Vírus Ebola/tratamento farmacológico , Doença pelo Vírus Ebola/imunologia , Animais , Anticorpos Monoclonais/biossíntese , Anticorpos Neutralizantes/administração & dosagem , Anticorpos Antivirais/administração & dosagem , Modelos Animais de Doenças , Feminino , Humanos , Células Matadoras Naturais/imunologia , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL
13.
Vaccine ; 34(24): 2729-36, 2016 05 23.
Artigo em Inglês | MEDLINE | ID: mdl-27102822

RESUMO

Enterovirus A71 infection has become a severe threat for global public health. Vaccines for controlling and preventing Enterovirus A71 epidemics are highly demanded, however, vaccine evaluation has been hindered by the lack of suitable Enterovirus A71 infection animal models. Here we established an hSCARB2 knockin mouse model for real-time monitoring of enterovirus A71 infection in vivo. This model was sensitive to the infection of both replication-competent virus rEV71(FY)-EGFP and single round pseudotype virus pEV71(FY)-Luc. The intensity of bioluminescence correlated well with viral loads in infected tissues (R=0.86, P<0.01). Pathological changes recapitulated human infectious and clinical features of enterovirus A71, including both general characteristics of "hand foot and mouth" and the severe symptoms in the CNS. A formalin-inactivated enterovirus A71 vaccine can elicit antibodies in R26-hSCARB2 mice, which play effective roles in protecting knockin mice against enterovirus A71 infection as indicated by bioluminescence. Therefore, this work provides a safe, sensitive and visualizing model for exploring mechanisms of enterovirus A71 infection and examining human enterovirus A71 vaccines and antiviral therapies.


Assuntos
Modelos Animais de Doenças , Doença de Mão, Pé e Boca/imunologia , Doença de Mão, Pé e Boca/patologia , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Enterovirus Humano A , Feminino , Técnicas de Introdução de Genes , Humanos , Medições Luminescentes , Proteínas de Membrana Lisossomal/genética , Masculino , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Mutagênese Insercional , Receptores Depuradores/genética , Vacinas de Produtos Inativados/imunologia , Carga Viral , Vacinas Virais/imunologia
14.
Mater Sci Eng C Mater Biol Appl ; 59: 1016-1024, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26652460

RESUMO

The inclusion complexation behavior, characterization and binding ability of hesperetin with ß-cyclodextrin and its derivatives were investigated in both the solution and solid state by means of XRD, DSC, SEM, (1)H and 2D NMR and UV-vis spectroscopy. The results showed that the water solubility and stability of hesperetin were obviously increased in the inclusion complex with cyclodextrins. This satisfactory water solubility and high stability of the hesperetin/CD complexes will be potentially useful for their application as herbal medicines or healthcare products.


Assuntos
Ciclodextrinas/química , Hesperidina/química , Estabilidade de Medicamentos , Ressonância Magnética Nuclear Biomolecular , Solubilidade
15.
Sci Rep ; 5: 11397, 2015 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-26235050

RESUMO

Due to the increasing concern of using smallpox virus as biological weapons for terrorist attack, there is renewed interest in studying the pathogenesis of human smallpox and development of new therapies. Animal models are highly demanded for efficacy and safety examination of new vaccines and therapeutic drugs. Here, we demonstrated that both wild type and immunodeficient rats infected with an engineered vaccinia virus carrying Firefly luciferase reporter gene (rTV-Fluc) could recapitulate infectious and clinical features of human smallpox. Vaccinia viral infection in wild type Sprague-Dawley (SD) rats displayed a diffusible pattern in various organs, including liver, head and limbs. The intensity of bioluminescence generated from rTV-Fluc correlated well with viral loads in tissues. Moreover, neutralizing antibodies had a protective effect against virus reinfection. The recombination activating gene 2 (Rag2) knockout rats generated by transcription activator-like effector nucleases (TALENs) technology were further used to examine the infectivity of the rTV-Fluc in immunodeficient populations. Here we demonstrated that Rag2-/- rats were more susceptible to rTV-Fluc than SD rats with a slower virus clearance rate. Therefore, the rTV-Fluc/SD rats and rTV-Fluc/Rag2-/- rats are suitable visualization models, which recapitulate wild type or immunodeficient populations respectively, for testing human smallpox vaccine and antiviral drugs.


Assuntos
Varíola/patologia , Vaccinia virus/patogenicidade , Animais , Animais Geneticamente Modificados/genética , Animais Geneticamente Modificados/metabolismo , Anticorpos Neutralizantes/uso terapêutico , Linfócitos B/citologia , Linfócitos B/imunologia , Linfócitos B/metabolismo , Sequência de Bases , Chlorocebus aethiops , Proteínas de Ligação a DNA/deficiência , Proteínas de Ligação a DNA/genética , Modelos Animais de Doenças , Feminino , Genes Reporter , Genótipo , Humanos , Hospedeiro Imunocomprometido , Células Matadoras Naturais/citologia , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Imagem Óptica , Ratos , Ratos Sprague-Dawley , Varíola/prevenção & controle , Varíola/virologia , Linfócitos T/citologia , Linfócitos T/imunologia , Linfócitos T/metabolismo , Vaccinia virus/genética , Células Vero
17.
Carbohydr Polym ; 98(1): 861-9, 2013 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-23987422

RESUMO

The inclusion complexation behavior, characterization and binding ability of naringenin with ß-cyclodextrin and its derivatives were investigated in both solution and the solid state by means of XRD, DSC, SEM, (1)H and 2D NMR and UV-vis spectroscopy. The results showed that the water solubility and thermal stability of naringenin were obviously increased in the inclusion complex with cyclodextrins. This satisfactory water solubility and high thermal stability of the naringenin/CD complexes will be potentially useful for their application as herbal medicines or healthcare products.


Assuntos
Flavanonas/química , Água/química , beta-Ciclodextrinas/química , Disponibilidade Biológica , Flavanonas/farmacocinética , Solubilidade
18.
Dev Biol ; 368(2): 304-11, 2012 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-22659081

RESUMO

Several research groups have suggested that the embryonic-abembryonic (Em-Ab) axis in the mouse can be predicted by the first cleavage plane of the early embryo. Currently, it is not known whether this early patterning occurs in cloned embryos produced by nuclear transfer and whether it affects development to term. In this work, the relationship between the first cleavage plane and the Em-Ab axis was determined by the labeling of one blastomere in cloned mouse embryos at the 2-cell stage, followed by ex-vivo tracking until the blastocyst stage. The results demonstrate that approximately half of the cloned blastocysts had an Em-Ab axis perpendicular to the initial cleavage plane of the 2-cell stage. These embryos were classified as "orthogonal" and the remainder as "deviant". Additionally, we report here that cloned embryos were significantly more often orthogonal than their naturally fertilized counterparts and overexpressed Sox2. Orthogonal cloned embryos demonstrated a higher rate of post-implantation embryonic development than deviant embryos, but cloned pups did not all survive. These results reveal that the angular relationship between the Em-Ab axis and the first cleavage plane can influence later development and they support the hypothesis that proper early patterning of mammalian embryos is required after nuclear transfer.


Assuntos
Blastocisto/citologia , Embrião de Mamíferos/citologia , Embrião de Mamíferos/embriologia , Desenvolvimento Embrionário , Animais , Blastocisto/metabolismo , Clonagem de Organismos , Transferência Embrionária , Embrião de Mamíferos/metabolismo , Feminino , Imunofluorescência , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Homeodomínio/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Microscopia Confocal , Proteína Homeobox Nanog , Técnicas de Transferência Nuclear , Fator 3 de Transcrição de Octâmero/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Transcrição SOXB1/genética
19.
Stem Cells Dev ; 21(16): 3001-9, 2012 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-22657835

RESUMO

Recently, reprogramming of somatic cells from a differentiated to pluripotent state by overexpression of specific external transcription factors has been accomplished. It has been widely speculated that an undifferentiated state may make donor cells more efficient for nuclear transfer. To test this hypothesis, we derived induced pluripotent stem cells (iPS cells) from several somatic cell lines: mouse embryonic fibroblast (MEF), adult tail tip fibroblast (TTF), and brain neural stem cells (NSCs). Three dimensional (3D)-fluorescent in situ hybridization (FISH) and quantitative-FISH (Q-FISH) were then used to evaluate constitutive (pericentric and telomeric) heterochromatin organization in these iPS cells and in their parental differentiated cells. Here, we show that important nuclear remodeling and telomeres rejuvenation occur in these iPS cells regardless of their parental origin. When we used these cells as donors for nuclear transfer, we produced live-born cloned mice at much higher rates with the iPS-induced cells than with the parental cell lines. Interestingly, we noticed that developmental potential after nuclear transfer could be correlated with telomere length of the donor cells. Altogether, our findings suggest that constitutive heterochromatin organization from differentiated somatic cells can be reprogrammed to the pluripotent state by induction of iPS cells, which in turn support nuclear transfer procedure quite efficiently.


Assuntos
Montagem e Desmontagem da Cromatina , Heterocromatina/metabolismo , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Técnicas de Transferência Nuclear , Animais , Animais Recém-Nascidos , Blastocisto/metabolismo , Peso Corporal , Diferenciação Celular , Linhagem Celular , Núcleo Celular/metabolismo , Células Clonais , Feminino , Hibridização in Situ Fluorescente , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Criação de Embriões para Pesquisa , Homeostase do Telômero
20.
Biochem Biophys Res Commun ; 397(3): 407-12, 2010 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-20510672

RESUMO

Somatic cell nuclear transfer (SCNT) has been successfully used in many species to produce live cloned offspring, albeit with low efficiency. The low frequency of successful development has usually been ascribed to incomplete or inappropriate reprogramming of the transferred nuclear genome. Elucidating the genetic differences between normal fertilized and cloned embryos is key to understand the low efficiency of SCNT. Here, we show that expression of HSPC117, which encodes a hypothetical protein of unknown function, was absent or very low in cloned mouse blastocysts. To investigate the role of HSPC117 in embryo development, we knocked-down this gene in normal fertilized embryos using RNA interference. We assessed the post-implantation survival of HSPC117 knock-down embryos at 3 stages: E9 (prior to placenta formation); E12 (after the placenta was fully functional) and E19 (post-natal). Our results show that, although siRNA-treated in vivo fertilized/produced (IVP) embryos could develop to the blastocyst stage and implanted without any difference from control embryos, the knock-down embryos showed substantial fetal death, accompanied by placental blood clotting, at E12. Furthermore, comparison of HSPC117 expression in placentas of nuclear transfer (NT), intracytoplasmic sperm injection (ICSI) and IVP embryos confirmed that HSPC117 deficiency correlates well with failures in embryo development: all NT embryos with a fetus, as well as IVP and ICSI embryos, had normal placental HSPC117 expression while those NT embryos showing reduced or no expression of HSPC117 failed to form a fetus. In conclusion, we show that HSPC117 is an important gene for post-implantation development of embryos, and that HSPC117 deficiency leads to fetal abnormalities after implantation, especially following placental formation. We suggest that defects in HSPC117 expression may be an important contributing factor to loss of cloned NT embryos in vivo.


Assuntos
Clonagem de Organismos , Desenvolvimento Embrionário/genética , Morte Fetal/genética , Técnicas de Transferência Nuclear , Placenta/anormalidades , Animais , Blastocisto/metabolismo , Feminino , Técnicas de Silenciamento de Genes , Camundongos , Camundongos Mutantes , Gravidez , Interferência de RNA , RNA Interferente Pequeno/genética , Injeções de Esperma Intracitoplásmicas , Transcrição Gênica
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...