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1.
J Health Psychol ; 27(13): 2951-2963, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35114825

RESUMO

The purpose of our study was to describe characteristics of behavior change techniques (BCTs) employed by popular YouTube fitness channels and examine relationships between BCTs used and engagement metrics (e.g. views, likes, comments). Seventy-five videos were coded according to BCT Taxonomy v1. Multi-level modeling was conducted between BCTs and engagement metrics. Fifty-four unique BCTs were used, with "Demonstration of behavior" and "Instruction on how to perform the behavior" used the most. The number of BCTs employed was 12.5 ± 6.65 and BCTs were all unrelated to engagement metrics (ps > 0.05). Application of BCTs within YouTube varies from traditional exercise interventions.


Assuntos
Mídias Sociais , Terapia Comportamental/métodos , Exercício Físico , Humanos
2.
Psychol Med ; 51(2): 300-309, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-31739818

RESUMO

BACKGROUND: A higher incidence of psychotic disorders has been consistently reported among black and other minority ethnic groups, particularly in northern Europe. It is unclear whether these rates have changed over time. METHODS: We identified all individuals with a first episode psychosis who presented to adult mental health services between 1 May 2010 and 30 April 2012 and who were resident in London boroughs of Lambeth and Southwark. We estimated age-and-gender standardised incidence rates overall and by ethnic group, then compared our findings to those reported in the Aetiology and Ethnicity of Schizophrenia and Other Psychoses (ÆSOP) study that we carried out in the same catchment area around 10 years earlier. RESULTS: From 9109 clinical records we identified 558 patients with first episode psychosis. Compared with ÆSOP, the overall incidence rates of psychotic disorder in southeast London have increased from 49.4 (95% confidence interval (CI) 43.6-55.3) to 63.1 (95% CI 57.3-69.0) per 100 000 person-years at risk. However, the overall incidence rate ratios (IRR) were reduced in some ethnic groups: for example, IRR (95% CI) for the black Caribbean group reduced from 6.7 (5.4-8.3) to 2.8 (2.1-3.6) and the 'mixed' group from 2.7 (1.8-4.2) to 1.4 (0.9-2.1). In the black African group, there was a negligible difference from 4.1 (3.2-5.3) to 3.5 (2.8-4.5). CONCLUSIONS: We found that incidence rates of psychosis have increased over time, and the IRR varied by the ethnic group. Future studies are needed to investigate more changes over time and determinants of change.


Assuntos
Etnicidade/psicologia , Transtornos Psicóticos/epidemiologia , Adolescente , Adulto , Fatores Etários , População Negra/psicologia , Emigrantes e Imigrantes/psicologia , Feminino , Humanos , Incidência , Londres/epidemiologia , Masculino , Pessoa de Meia-Idade , Grupos Minoritários/psicologia , Esquizofrenia/epidemiologia , População Branca/psicologia , Adulto Jovem
3.
Int J Surg Pathol ; 28(4): 401-405, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31948309

RESUMO

Glomus tumor can rarely arise in the central nervous system as a sella turcica mass. In this article, we report a case of sellar glomus tumor in a female patient who presented at the age of 8 years with visual impairment. The tumor recurred at 4 years and 26 years after initial excision and gamma knife therapy. Histologic examination showed a monotonous population of oval cells accompanied by delicate blood vessels, features mimicking pituitary adenoma. The tumor showed histologic progression at the second recurrence. Synaptophysin staining was positive, but chromogranin and CD56 were negative. The tumor cells were negative for epithelial markers but expressed actin and SMA. Awareness of the rare occurrence of glomus tumor at this region, careful analysis of morphology, and appropriate immunohistochemical workup are essential to solve this diagnostic challenge. The clinicopathologic features of all previously reported cases are reviewed.


Assuntos
Adenoma/diagnóstico , Tumor Glômico/diagnóstico , Recidiva Local de Neoplasia/diagnóstico , Neoplasias Hipofisárias/diagnóstico , Neoplasias Cranianas/diagnóstico , Adulto , Craniotomia , Diagnóstico Diferencial , Progressão da Doença , Feminino , Tumor Glômico/patologia , Tumor Glômico/terapia , Humanos , Imageamento por Ressonância Magnética , Recidiva Local de Neoplasia/patologia , Recidiva Local de Neoplasia/terapia , Radiocirurgia , Sela Túrcica/diagnóstico por imagem , Sela Túrcica/patologia , Sela Túrcica/cirurgia , Neoplasias Cranianas/patologia , Neoplasias Cranianas/terapia , Sinaptofisina/metabolismo
4.
Exp Hematol ; 76: 1-12.e5, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31326613

RESUMO

Pluripotent stem cell (PSC) differentiation in vitro represents a powerful and tractable model to study mammalian development and an unlimited source of cells for regenerative medicine. Within hematology, in vitro PSC hematopoiesis affords novel insights into blood formation and represents an exciting potential approach to generate hematopoietic and immune cell types for transplantation and transfusion. Most studies to date have focused on in vitro hematopoiesis from mouse PSCs and human PSCs. However, differences in mouse and human PSC culture protocols have complicated the translation of discoveries between these systems. We recently developed a novel chemical media formulation, expanded potential stem cell medium (EPSCM), that maintains mouse PSCs in a unique cellular state and extraembryonic differentiation capacity. Herein, we describe how EPSCM can be directly used to stably maintain human PSCs. We further demonstrate that human PSCs maintained in EPSCM can spontaneously form embryoid bodies and undergo in vitro hematopoiesis using a simple differentiation protocol, similar to mouse PSC differentiation. EPSCM-maintained human PSCs generated at least two hematopoietic cell populations, which displayed distinct transcriptional profiles by RNA-sequencing (RNA-seq) analysis. EPSCM also supports gene targeting using homologous recombination, affording generation of an SPI1 (PU.1) reporter PSC line to study and track in vitro hematopoiesis. EPSCM therefore provides a useful tool not only to study pluripotency but also hematopoietic cell specification and developmental-lineage commitment.


Assuntos
Meios de Cultura/farmacologia , Hematopoese/efeitos dos fármacos , Células-Tronco Embrionárias Humanas/efeitos dos fármacos , Células-Tronco Pluripotentes/efeitos dos fármacos , Animais , Técnicas de Cultura de Células/métodos , Ciclo Celular , Linhagem da Célula , Células Cultivadas , Técnicas de Reprogramação Celular , Corpos Embrioides/efeitos dos fármacos , Fibroblastos/citologia , Genes Reporter , Células-Tronco Embrionárias Humanas/citologia , Humanos , Camundongos , Células-Tronco Neurais/citologia , Células-Tronco Neurais/efeitos dos fármacos , Células-Tronco Pluripotentes/citologia , Células-Tronco Pluripotentes/transplante , Análise de Sequência de RNA , Especificidade da Espécie , Transplante de Células-Tronco/efeitos adversos , Teratoma/etiologia
5.
J Acoust Soc Am ; 145(4): 2435, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-31046370

RESUMO

The objective of the current paper was to characterize indoor wind turbine sound pressure levels (SPLs) to assess the audibility of wind turbine noise indoors, accounting for window opening, frequency spectra, and presbycusis. Loudspeaker generated noise was used to determine the outdoor to indoor SPL differences at 11 representative dwellings using ISO 140-5:1998. The procedure was extended to 16 Hz. With windows closed, indoor broadband A- and C-weighted SPLs were lower by 25.9 and 15.3 dB, respectively, for wind turbine noise spectra. With windows opened, the corresponding results were 13.8 and 9.9 dB, respectively. Standard deviations for these results were 3 dB so that indoor and outdoor SPL would tend to be highly correlated. For 35 dBA outdoor SPL, the indoor SPL was potentially audible at frequencies as low as 31.5 Hz. Specifically, at 35 dBA, 80% to 100% of adults below the age of 60 years, would potentially be able to hear wind turbine noise indoors with windows partially open. This would drop to 10% to 30% with closed windows. Uncertainties around these estimates are discussed.

6.
Prenat Diagn ; 39(2): 88-99, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30575063

RESUMO

OBJECTIVE: Cell-free DNA (cfDNA) fragments in maternal plasma contain DNA damage and may negatively impact the sensitivity of noninvasive prenatal testing (NIPT). However, some of these DNA damages are potentially reparable. We aimed to recover these damaged cfDNA molecules using PreCR DNA repair mix. METHODS: cfDNA was extracted from 20 maternal plasma samples and was repaired and sequenced by the Illumina platform. Size profiles and fetal DNA fraction changes of repaired samples were characterized. Targeted sequencing of chromosome Y sequences was used to enrich fetal cfDNA molecules following repair. Single-molecule real-time (SMRT) sequencing platform was employed to characterize long (>250 bp) cfDNA molecules. NIPT of five trisomy 21 samples was performed. RESULTS: Size profiles of repaired libraries were altered, with significantly increased long (>250 bp) cfDNA molecules. Single nucleotide polymorphism (SNP)-based analyses showed that both fetal- and maternal-derived cfDNA molecules were enriched by the repair. Fetal DNA fractions in maternal plasma showed a small but consistent (4.8%) increase, which were contributed by a higher increment of long fetal cfDNA molecules. z-score values were improved in NIPT of all trisomy 21 samples. CONCLUSION: Plasma DNA repair recovers and enriches long cfDNA molecules of both fetal and maternal origins in maternal plasma.


Assuntos
Ácidos Nucleicos Livres/sangue , Reparo do DNA/fisiologia , Feto/metabolismo , Mães , Análise Mutacional de DNA/métodos , Feminino , Técnicas de Genotipagem/métodos , Humanos , Testes para Triagem do Soro Materno/métodos , Análise em Microsséries , Polimorfismo de Nucleotídeo Único , Gravidez , Primeiro Trimestre da Gravidez/sangue , Terceiro Trimestre da Gravidez/sangue , Diagnóstico Pré-Natal/métodos , Trissomia/diagnóstico , Trissomia/genética
7.
Genome Med ; 10(1): 71, 2018 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-30236153

RESUMO

BACKGROUND: We have previously reported an antigen-specific protocol to induce transplant tolerance and linked suppression to human embryonic stem cell (hESC)-derived tissues in immunocompetent mice through coreceptor and costimulation blockade. However, the exact mechanisms of acquired immune tolerance in this model have remained unclear. METHODS: We utilize the NOD.Foxp3hCD2 reporter mouse line and an ablative anti-hCD2 antibody to ask if CD4+FOXP3+ regulatory T cells (Treg) are required for coreceptor and costimulation blockade-induced immune tolerance. We also perform genome-wide single-cell RNA-sequencing to interrogate Treg during immune rejection and tolerance and to indicate possible mechanisms involved in sustaining Treg function. RESULTS: We show that Treg are indispensable for tolerance induced by coreceptor and costimulation blockade as depletion of which with an anti-hCD2 antibody resulted in rejection of hESC-derived pancreatic islets in NOD.Foxp3hCD2 mice. Single-cell transcriptomic profiling of 12,964 intragraft CD4+ T cells derived from rejecting and tolerated grafts reveals that Treg are heterogeneous and functionally distinct in the two outcomes of transplant rejection and tolerance. Treg appear to mainly promote chemotactic and ubiquitin-dependent protein catabolism during transplant rejection while seeming to harness proliferative and immunosuppressive function during tolerance. We also demonstrate that this form of acquired transplant tolerance is associated with increased proliferation and PD-1 expression by Treg. Blocking PD-1 signaling with a neutralizing anti-PD-1 antibody leads to reduced Treg proliferation and graft rejection. CONCLUSIONS: Our results suggest that short-term coreceptor and costimulation blockade mediates immune tolerance to hESC-derived pancreatic islets by promoting Treg proliferation through engagement of PD-1. Our findings could give new insights into clinical development of hESC-derived pancreatic tissues, combined with immunotherapies that expand intragraft Treg, as a potentially sustainable alternative treatment for T1D.


Assuntos
Perfilação da Expressão Gênica , Tolerância Imunológica/genética , Receptor de Morte Celular Programada 1/metabolismo , Análise de Célula Única , Linfócitos T Reguladores/imunologia , Animais , Linfócitos T CD4-Positivos/imunologia , Contagem de Células , Linhagem Celular , Proliferação de Células/genética , Sobrevivência Celular , Células-Tronco Embrionárias/citologia , Células-Tronco Embrionárias/metabolismo , Genoma , Rejeição de Enxerto/imunologia , Humanos , Ilhotas Pancreáticas/citologia , Transplante das Ilhotas Pancreáticas , Camundongos Endogâmicos C57BL , Transdução de Sinais , Baço/citologia
8.
Nature ; 550(7676): 393-397, 2017 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-29019987

RESUMO

Mouse embryonic stem cells derived from the epiblast contribute to the somatic lineages and the germline but are excluded from the extra-embryonic tissues that are derived from the trophectoderm and the primitive endoderm upon reintroduction to the blastocyst. Here we report that cultures of expanded potential stem cells can be established from individual eight-cell blastomeres, and by direct conversion of mouse embryonic stem cells and induced pluripotent stem cells. Remarkably, a single expanded potential stem cell can contribute both to the embryo proper and to the trophectoderm lineages in a chimaera assay. Bona fide trophoblast stem cell lines and extra-embryonic endoderm stem cells can be directly derived from expanded potential stem cells in vitro. Molecular analyses of the epigenome and single-cell transcriptome reveal enrichment for blastomere-specific signature and a dynamic DNA methylome in expanded potential stem cells. The generation of mouse expanded potential stem cells highlights the feasibility of establishing expanded potential stem cells for other mammalian species.


Assuntos
Blastômeros/citologia , Células-Tronco Embrionárias Murinas/citologia , Animais , Blastocisto/citologia , Blastômeros/metabolismo , Linhagem da Célula , Células Cultivadas , Quimera , Embrião de Mamíferos/citologia , Endoderma/citologia , Epigênese Genética , Epigenômica , Feminino , Masculino , Camundongos , Células-Tronco Embrionárias Murinas/metabolismo , Placenta/citologia , Células-Tronco Pluripotentes/citologia , Células-Tronco Pluripotentes/metabolismo , Gravidez , Análise de Célula Única , Transcriptoma , Trofoblastos/citologia
9.
Proc Natl Acad Sci U S A ; 114(37): E7786-E7795, 2017 09 12.
Artigo em Inglês | MEDLINE | ID: mdl-28830992

RESUMO

The human placenta is a dynamic and heterogeneous organ critical in the establishment of the fetomaternal interface and the maintenance of gestational well-being. It is also the major source of cell-free fetal nucleic acids in the maternal circulation. Placental dysfunction contributes to significant complications, such as preeclampsia, a potentially lethal hypertensive disorder during pregnancy. Previous studies have identified significant changes in the expression profiles of preeclamptic placentas using whole-tissue analysis. Moreover, studies have shown increased levels of targeted RNA transcripts, overall and placental contributions in maternal cell-free nucleic acids during pregnancy progression and gestational complications, but it remains infeasible to noninvasively delineate placental cellular dynamics and dysfunction at the cellular level using maternal cell-free nucleic acid analysis. In this study, we addressed this issue by first dissecting the cellular heterogeneity of the human placenta and defined individual cell-type-specific gene signatures by analyzing more than 24,000 nonmarker selected cells from full-term and early preeclamptic placentas using large-scale microfluidic single-cell transcriptomic technology. Our dataset identified diverse cellular subtypes in the human placenta and enabled reconstruction of the trophoblast differentiation trajectory. Through integrative analysis with maternal plasma cell-free RNA, we resolved the longitudinal cellular dynamics of hematopoietic and placental cells in pregnancy progression. Furthermore, we were able to noninvasively uncover the cellular dysfunction of extravillous trophoblasts in early preeclamptic placentas. Our work showed the potential of integrating transcriptomic information derived from single cells into the interpretation of cell-free plasma RNA, enabling the noninvasive elucidation of cellular dynamics in complex pathological conditions.


Assuntos
Ácidos Nucleicos Livres/análise , Placenta/fisiologia , Análise de Célula Única/métodos , Ácidos Nucleicos Livres/sangue , Ácidos Nucleicos Livres/metabolismo , Feminino , Humanos , Técnicas Analíticas Microfluídicas/métodos , Placenta/metabolismo , Plasma/metabolismo , Pré-Eclâmpsia/genética , Gravidez , RNA/análise , RNA/sangue , Transcriptoma/genética , Trofoblastos/metabolismo
11.
Clin Chem ; 63(5): 1031-1037, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28280050

RESUMO

BACKGROUND: Recent studies have suggested that single-stranded DNA (ssDNA) library preparation can enrich short DNA species from the plasma of healthy individuals, cancer patients, and transplant recipients. Based on previous observations that fetal DNA molecules in the maternal plasma are shorter than maternal DNA molecules, ssDNA library preparation may potentially enrich fetal DNA and provide substantial improvement in noninvasive prenatal testing. METHODS: We tested this hypothesis by comparing the maternal plasma DNA sequencing results using 2 types of ssDNA library preparation methods and a standard double-stranded DNA (dsDNA) library method using samples from first- and third-trimester pregnancies. We also evaluated the performance of ssDNA and dsDNA library methods in the noninvasive prenatal detection of trisomy 21 from maternal plasma. RESULTS: Short DNA species were significantly enriched in ssDNA libraries. However, contrary to previous speculation, no significant enrichment was observed in the overall fetal fraction in maternal plasma collected in the first trimester. Our use of an ssDNA library did not reduce the variation in chromosomal representation when compared with a standard dsDNA library in the first-trimester plasma samples. ssDNA libraries also showed inferior performance in the noninvasive prenatal detection of trisomy 21 from maternal plasma. Detailed fetal fraction analysis using size-fractionated Y chromosome sequences and fetal-specific single-nucleotide polymorphisms (SNPs) revealed an unexpected finding that short maternal DNA was preferentially enriched over short fetal DNA in an ssDNA library irrespective of GC content. CONCLUSIONS: Our findings have shown that ssDNA library preparation preferentially enriches short maternally derived DNA in maternal plasma.


Assuntos
DNA de Cadeia Simples , DNA/sangue , Biblioteca Gênica , Biologia Molecular/normas , DNA/química , DNA/genética , Feminino , Humanos , Masculino , Dados de Sequência Molecular , Gravidez
12.
Nature ; 539(7627): 102-106, 2016 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-27749818

RESUMO

Innate lymphoid cells (ILCs) functionally resemble T lymphocytes in cytotoxicity and cytokine production but lack antigen-specific receptors, and they are important regulators of immune responses and tissue homeostasis. ILCs are generated from common lymphoid progenitors, which are subsequently committed to innate lymphoid lineages in the α-lymphoid progenitor, early innate lymphoid progenitor, common helper innate lymphoid progenitor and innate lymphoid cell progenitor compartments. ILCs consist of conventional natural killer cells and helper-like cells (ILC1, ILC2 and ILC3). Despite recent advances, the cellular heterogeneity, developmental trajectory and signalling dependence of ILC progenitors are not fully understood. Here, using single-cell RNA-sequencing (scRNA-seq) of mouse bone marrow progenitors, we reveal ILC precursor subsets, delineate distinct ILC development stages and pathways, and report that high expression of programmed death 1 (PD-1hi) marked a committed ILC progenitor that was essentially identical to an innate lymphoid cell progenitor. Our data defined PD-1hiIL-25Rhi as an early checkpoint in ILC2 development, which was abolished by deficiency in the zinc-finger protein Bcl11b but restored by IL-25R overexpression. Similar to T lymphocytes, PD-1 was upregulated on activated ILCs. Administration of a PD-1 antibody depleted PD-1hi ILCs and reduced cytokine levels in an influenza infection model in mice, and blocked papain-induced acute lung inflammation. These results provide a perspective for exploring PD-1 and its ligand (PD-L1) in immunotherapy, and allow effective manipulation of the immune system for disease prevention and therapy.


Assuntos
Sequência de Bases , Linhagem da Célula , Imunidade Inata , Linfócitos/citologia , Células Progenitoras Linfoides/citologia , Receptor de Morte Celular Programada 1/metabolismo , Análise de Célula Única , Animais , Anticorpos/imunologia , Diferenciação Celular , Linhagem da Célula/genética , Separação Celular , Citocinas/imunologia , Citocinas/metabolismo , Modelos Animais de Doenças , Humanos , Imunoterapia/tendências , Influenza Humana/imunologia , Influenza Humana/metabolismo , Células Matadoras Naturais/citologia , Ativação Linfocitária , Linfócitos/imunologia , Linfócitos/metabolismo , Células Progenitoras Linfoides/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Pneumonia/imunologia , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Receptor de Morte Celular Programada 1/genética , Receptor de Morte Celular Programada 1/imunologia , Receptores de Interleucina/metabolismo , Proteínas Repressoras/deficiência , Proteínas Repressoras/metabolismo , Linfócitos T/metabolismo , Proteínas Supressoras de Tumor/deficiência , Proteínas Supressoras de Tumor/metabolismo
13.
J Acoust Soc Am ; 139(3): 1431-5, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27036281

RESUMO

This paper provides experimental validation of the sound power level data obtained from manufacturers for the ten wind turbine models examined in Health Canada's Community Noise and Health Study (CNHS). Within measurement uncertainty, the wind turbine sound power levels measured using IEC 61400-11 [(2002). (International Electrotechnical Commission, Geneva)] were consistent with the sound power level data provided by manufacturers. Based on measurements, the sound power level data were also extended to 16 Hz for calculation of C-weighted levels. The C-weighted levels were 11.5 dB higher than the A-weighted levels (standard deviation 1.7 dB). The simple relationship between A- and C- weighted levels suggests that there is unlikely to be any statistically significant difference between analysis based on either C- or A-weighted data.

14.
J Acoust Soc Am ; 139(3): 1436-42, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27036282

RESUMO

This paper provides calculations of outdoor sound pressure levels (SPLs) at dwellings for 10 wind turbine models, to support Health Canada's Community Noise and Health Study. Manufacturer supplied and measured wind turbine sound power levels were used to calculate outdoor SPL at 1238 dwellings using ISO [(1996). ISO 9613-2-Acoustics] and a Swedish noise propagation method. Both methods yielded statistically equivalent results. The A- and C-weighted results were highly correlated over the 1238 dwellings (Pearson's linear correlation coefficient r > 0.8). Calculated wind turbine SPLs were compared to ambient SPLs from other sources, estimated using guidance documents from the United States and Alberta, Canada.

15.
Cell Stem Cell ; 17(4): 471-85, 2015 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-26431182

RESUMO

Embryonic stem cell (ESC) culture conditions are important for maintaining long-term self-renewal, and they influence cellular pluripotency state. Here, we report single cell RNA-sequencing of mESCs cultured in three different conditions: serum, 2i, and the alternative ground state a2i. We find that the cellular transcriptomes of cells grown in these conditions are distinct, with 2i being the most similar to blastocyst cells and including a subpopulation resembling the two-cell embryo state. Overall levels of intercellular gene expression heterogeneity are comparable across the three conditions. However, this masks variable expression of pluripotency genes in serum cells and homogeneous expression in 2i and a2i cells. Additionally, genes related to the cell cycle are more variably expressed in the 2i and a2i conditions. Mining of our dataset for correlations in gene expression allowed us to identify additional components of the pluripotency network, including Ptma and Zfp640, illustrating its value as a resource for future discovery.


Assuntos
Células-Tronco Embrionárias Murinas/fisiologia , RNA/genética , Transcriptoma , Animais , Diferenciação Celular/genética , Células Cultivadas , Quinase 3 da Glicogênio Sintase/antagonistas & inibidores , Quinase 3 da Glicogênio Sintase/metabolismo , MAP Quinase Quinase 1/antagonistas & inibidores , MAP Quinase Quinase 1/metabolismo , Camundongos , Células-Tronco Embrionárias Murinas/citologia , RNA/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Análise de Célula Única
16.
Genome Biol ; 16: 178, 2015 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-26387834

RESUMO

BACKGROUND: Hematopoietic stem cells (HSCs) are a rare cell type with the ability of long-term self-renewal and multipotency to reconstitute all blood lineages. HSCs are typically purified from the bone marrow using cell surface markers. Recent studies have identified significant cellular heterogeneities in the HSC compartment with subsets of HSCs displaying lineage bias. We previously discovered that the transcription factor Bcl11a has critical functions in the lymphoid development of the HSC compartment. RESULTS: In this report, we employ single-cell transcriptomic analysis to dissect the molecular heterogeneities in HSCs. We profile the transcriptomes of 180 highly purified HSCs (Bcl11a (+/+) and Bcl11a (-/-)). Detailed analysis of the RNA-seq data identifies cell cycle activity as the major source of transcriptomic variation in the HSC compartment, which allows reconstruction of HSC cell cycle progression in silico. Single-cell RNA-seq profiling of Bcl11a (-/-) HSCs reveals abnormal proliferative phenotypes. Analysis of lineage gene expression suggests that the Bcl11a (-/-) HSCs are constituted of two distinct myeloerythroid-restricted subpopulations. Remarkably, similar myeloid-restricted cells could also be detected in the wild-type HSC compartment, suggesting selective elimination of lymphoid-competent HSCs after Bcl11a deletion. These defects are experimentally validated in serial transplantation experiments where Bcl11a (-/-) HSCs are myeloerythroid-restricted and defective in self-renewal. CONCLUSIONS: Our study demonstrates the power of single-cell transcriptomics in dissecting cellular process and lineage heterogeneities in stem cell compartments, and further reveals the molecular and cellular defects in the Bcl11a-deficient HSC compartment.


Assuntos
Proteínas de Transporte/genética , Ciclo Celular , Linhagem da Célula , Células-Tronco Hematopoéticas/citologia , Linfopoese , Proteínas Nucleares/genética , Transcriptoma , Animais , Proteínas de Transporte/metabolismo , Proliferação de Células , Células Cultivadas , Proteínas de Ligação a DNA , Células-Tronco Hematopoéticas/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Nucleares/metabolismo , Fenótipo , Proteínas Repressoras , Análise de Célula Única
17.
Nucleic Acids Res ; 42(20): e155, 2014 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-25223790

RESUMO

The transcription activator-like effectors (TALEs) and the RNA-guided clustered regularly interspaced short palindromic repeat (CRISPR) associated protein (Cas9) utlilize distinct molecular mechanisms in targeting site recognition. The two proteins can be modified to carry additional functional domains to regulate expression of genomic loci in mammalian cells. In this study, we have compared the two systems in activation and suppression of the Oct4 and Nanog loci by targeting their enhancers. Although both are able to efficiently activate the luciferase reporters, the CRISPR/dCas9 system is much less potent in activating the endogenous loci and in the application of reprogramming somatic cells to iPS cells. Nevertheless, repression by CRISPR/dCas9 is comparable to or even better than TALE repressors. We demonstrated that dCas9 protein binding results in significant physical interference to binding of native transcription factors at enhancer, less efficient active histone markers induction or recruitment of activating complexes in gene activation. This study thus highlighted the merits and drawbacks of transcription regulation by each system. A combined approach of TALEs and CRISPR/dCas9 should provide an optimized solution to regulate genomic loci and to study genetic elements such as enhancers in biological processes including somatic cell reprogramming and guided differentiation.


Assuntos
Proteínas Associadas a CRISPR/metabolismo , Elementos Facilitadores Genéticos , Regulação da Expressão Gênica , Fatores de Transcrição/metabolismo , Animais , Ligação Competitiva , Células Cultivadas , Reprogramação Celular , Epigênese Genética , Biblioteca Gênica , Vetores Genéticos , Células-Tronco Pluripotentes Induzidas/metabolismo , Camundongos , Fator 3 de Transcrição de Octâmero/genética , Plasmídeos/genética , Proteínas Repressoras/metabolismo , Ativação Transcricional
18.
Curr Opin Genet Dev ; 28: 1-9, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25151337

RESUMO

Recent researches have identified multiple transcription factors as permissible reprogramming factors to pluripotency and lineage switching. The current standard strategy by ectopic factor overexpression however has intrinsic limitations in studying the reprogramming mechanism. There is a growing interest in engineering novel chimeric reprogramming factors and applying designer transcription factors technology to improve reprogramming efficiency and dissect the process of endogenous pluripotency network reactivation. Here, we provide a concise review on the latest progress in studying cellular reprogramming by transcription factor engineering.


Assuntos
Reprogramação Celular , Engenharia Genética/métodos , Células-Tronco Pluripotentes/citologia , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Animais , Diferenciação Celular , Humanos
19.
Artigo em Inglês | MEDLINE | ID: mdl-26734252

RESUMO

Iatrogenic Paracetamol toxicity is a potentially life-threatening yet avoidable cause of acute liver failure. Unfortunately, several cases have recently been reported nationally (1,2). The impetus behind our project was a recent case of iatrogenic Paracetamol induced hepatotoxicity within our trust, a London-based District General Hospital. According to the British National Formulary, for adults weighing 10-50kg the intravenous (IV) dose is 15mg/kg every 4-6hours (max. 60mg/kg daily), not the usual 1 gram QDS oral dose which is applied irrespective of weight (3). We audited 100 adult patients in April 2013 and re-audited in July 2013. Both of the randomly selected samples consisted of an equal number of surgical and medical patients, with an equal gender ratio. Data of interest included whether patients were on IV Paracetamol, appropriately dosed; if and when patients had been weighed during admission; and whether the WHO pain ladder of analgesia was followed. Identified shortcomings included patient weight on admission not being recorded, and IV Paracetamol dose adjustment not being made in patients <50kg. 3 months were spent raising awareness of the importance to record patient weights and to dose-adjust IV Paracetamol when indicated. Patients weighed on admission improved from 37% to 68% (p<0.0001) and those on the inappropriate dose of Paracetamol fell from 18 (25% of the patients on Paracetamol) to 5 (5.75% of the patients on Paracetamol) p=0.0013. There was a marked improvement in the number of patients with the weight written on their drug chart from 27% to 53% post-intervention. (p=0.0003) In conclusion, every patient should be weighed on admission. In order to prevent potential hepatotoxicity, staff should document patient weights on the drug charts and be aware of the fact that patients who weigh <50 kg should be on a 15 mg/kg/dose of IV Paracetamol, not 1 gram QDS.

20.
Stem Cell Reports ; 1(2): 183-97, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24052952

RESUMO

The modular DNA recognition code of the transcription-activator-like effectors (TALEs) from plant pathogenic bacterial genus Xanthomonas provides a powerful genetic tool to create designer transcription factors (dTFs) targeting specific DNA sequences for manipulating gene expression. Previous studies have suggested critical roles of enhancers in gene regulation and reprogramming. Here, we report dTF activator targeting the distal enhancer of the Pou5f1 (Oct4) locus induces epigenetic changes, reactivates its expression, and substitutes exogenous OCT4 in reprogramming mouse embryonic fibroblast cells (MEFs) to induced pluripotent stem cells (iPSCs). Similarly, dTF activator targeting a Nanog enhancer activates Nanog expression and reprograms epiblast stem cells (EpiSCs) to iPSCs. Conversely, dTF repressors targeting the same genetic elements inhibit expression of these loci, and effectively block reprogramming. This study indicates that dTFs targeting specific enhancers can be used to study other biological processes such as transdifferentiation or directed differentiation of stem cells.


Assuntos
Reprogramação Celular , Células-Tronco Embrionárias/metabolismo , Células-Tronco Pluripotentes Induzidas/metabolismo , Fatores de Transcrição/metabolismo , Animais , Células Cultivadas , Epigênese Genética , Regulação da Expressão Gênica , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Camundongos , Proteína Homeobox Nanog , Fator 3 de Transcrição de Octâmero/genética , Fator 3 de Transcrição de Octâmero/metabolismo , Sequências Reguladoras de Ácido Nucleico , Fatores de Transcrição/genética
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