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1.
Bioinformatics ; 36(8): 2587-2588, 2020 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-31841127

RESUMO

MOTIVATION: High throughput next generation sequencing (NGS) has become exceedingly cheap, facilitating studies to be undertaken containing large sample numbers. Quality control (QC) is an essential stage during analytic pipelines and the outputs of popular bioinformatics tools such as FastQC and Picard can provide information on individual samples. Although these tools provide considerable power when carrying out QC, large sample numbers can make inspection of all samples and identification of systemic bias a challenge. RESULTS: We present ngsReports, an R package designed for the management and visualization of NGS reports from within an R environment. The available methods allow direct import into R of FastQC reports along with outputs from other tools. Visualization can be carried out across many samples using default, highly customizable plots with options to perform hierarchical clustering to quickly identify outlier libraries. Moreover, these can be displayed in an interactive shiny app or HTML report for ease of analysis. AVAILABILITY AND IMPLEMENTATION: The ngsReports package is available on Bioconductor and the GUI shiny app is available at https://github.com/UofABioinformaticsHub/shinyNgsreports. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Assuntos
Sequenciamento de Nucleotídeos em Larga Escala , Software , Viés , Controle de Qualidade
2.
Platelets ; 32(8): 998-1008, 2021 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-33284715

RESUMO

Ionotropic glutamate receptors include α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPAR), kainate receptors (KAR), and N-methyl-D-aspartate receptors (NMDAR). All function as cation channels; AMPAR and KAR are more permeable to sodium and NMDAR to calcium ions. Compared to the brain, receptor assemblies in platelets are unusual, suggesting distinctive functionalities.There is convincing evidence that AMPAR and KAR amplify platelet function and thrombus formation in vitro and in vivo. Transgenic mice lacking GluA1 and GluK2 (AMPAR and KAR subunits, respectively) have longer bleeding times and prolonged time to thrombosis in an arterial model. In humans, rs465566 KAR gene polymorphism associates with altered in vitro platelet responses suggesting enhanced aspirin effect. The NMDAR contribution to platelet function is less well defined. NMDA at low concentrations (≤10 µM) inhibits platelet aggregation and high concentrations (≥100 µM) have no effect. However, open NMDAR channel blockers interfere with platelet activation and aggregation induced by other agonists in vitro; anti-GluN1 antibodies interfere with thrombus formation under high shear rates ex vivo; and rats vaccinated with GluN1 develop iron deficiency anemia suggestive of mild chronic bleeding. In this review, we summarize data on glutamate receptors in platelets and propose a unifying model that reconciles some of the opposing effects observed.


Assuntos
Plaquetas/metabolismo , Receptores Ionotrópicos de Glutamato/metabolismo , Animais , Humanos , Masculino , Ratos
3.
Int J Mol Sci ; 21(21)2020 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-33182365

RESUMO

Ischaemic brain damage induces autoimmune responses, including the production of autoantibodies with potential neuroprotective effects. Platelets share unexplained similarities with neurons, and the formation of anti-platelet antibodies has been documented in neurological disorders. The aim of this study was to investigate the presence of anti-platelet antibodies in the peripheral blood of patients after ischaemic stroke and determine any clinical correlations. Using a flow cytometry-based platelet immunofluorescence method, we detected platelet-reactive antibodies in 15 of 48 (31%) stroke patients and two of 50 (4%) controls (p < 0.001). Western blotting revealed heterogeneous reactivities with platelet proteins, some of which overlapped with brain proteins. Stroke patients who carried anti-platelet antibodies presented with larger infarcts and more severe neurological dysfunction, which manifested as higher scores on the National Institutes of Health Stroke Scale (NIHSS; p = 0.009), but they had a greater recovery in the NIHSS by the time of hospital discharge (day 7 ± 2) compared with antibody-negative patients (p = 0.043). Antibodies from stroke sera reacted more strongly with activated platelets (p = 0.031) and inhibited platelet aggregation by up to 30.1 ± 2.8% (p < 0.001), suggesting the potential to interfere with thrombus formation. In conclusion, platelet-reactive antibodies can be found in patients soon after ischaemic stroke and correlate with better short-term outcomes, suggesting a potential novel mechanism limiting thrombosis.


Assuntos
Autoanticorpos/imunologia , Plaquetas/imunologia , Isquemia Encefálica/imunologia , AVC Isquêmico/imunologia , Idoso , Autoimunidade/imunologia , Coagulação Sanguínea/imunologia , Feminino , Humanos , Masculino , Agregação Plaquetária/imunologia , Contagem de Plaquetas/métodos , Trombose/imunologia
4.
Insect Mol Biol ; 28(6): 873-886, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31150140

RESUMO

Bactrocera tryoni (Queensland fruit fly) are polyphagous horticultural pests of eastern Australia. Heterogametic males contain a sex-determining Y-chromosome thought to be gene poor and repetitive. Here, we report 39 Y-chromosome scaffolds (~700 kb) from B. tryoni identified using genotype-by-sequencing data and whole-genome resequencing. Male diagnostic PCR assays validated eight Y-scaffolds, and one (Btry4096) contained a novel gene with five exons that encode a predicted 575 amino acid protein. The Y-gene, referred to as typo-gyf, is a truncated Y-chromosome paralogue of X-chromosome gene gyf (1773 aa). The Y-chromosome contained ~41 copies of typo-gyf, and expression occurred in male flies and embryos. Analysis of 13 tephritid transcriptomes confirmed typo-gyf expression in six additional Bactrocera species, including Bactrocera latifrons, Bactrocera dorsalis and Bactrocera zonata. Molecular dating estimated typo-gyf evolved within the past 8.02 million years (95% highest posterior density 10.56-5.52 million years), after the split with Bactrocera oleae. Phylogenetic analysis also highlighted complex evolutionary histories among several Bactrocera species, as discordant nuclear (116 genes) and mitochondrial (13 genes) topologies were observed. B. tryoni Y-sequences may provide useful sites for future transgene insertions, and typo-gyf could act as a Y-chromosome diagnostic marker for many Bactrocera species, although its function is unknown.


Assuntos
Cromossomos de Insetos/genética , Proteínas de Insetos/genética , Tephritidae/genética , Sequência de Aminoácidos , Animais , Feminino , Proteínas de Insetos/química , Proteínas de Insetos/metabolismo , Masculino , Filogenia , Alinhamento de Sequência
5.
Med J Aust ; 210(11): 509-516, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31155728

RESUMO

INTRODUCTION: Heparin-induced thrombocytopenia (HIT) is a prothrombotic disorder that occurs following the administration of heparin and is caused by antibodies to platelet factor 4 and heparin. Diagnosis of HIT is essential to guide treatment strategies using non-heparin anticoagulants and to avoid unwanted and potential fatal thromboembolic complications. This consensus statement, formulated by members of the Thrombosis and Haemostasis Society of Australia and New Zealand, provides an update on HIT pathogenesis and guidance on the diagnosis and management of patients with suspected or confirmed HIT. MAIN RECOMMENDATIONS: A 4Ts score is recommended for all patients with suspected HIT prior to laboratory testing. Further laboratory testing with a screening immunoassay or confirmatory functional assay is not recommended in individuals with a low 4Ts score. However, if there are missing or unreliable clinical data, then laboratory testing should be performed. A positive functional assay result confirms the diagnosis of HIT and should be performed to confirm a positive immunoassay result. Heparin exposure must be ceased in patients with suspected or confirmed HIT and initial treatment with a non-heparin alternative instituted. Non-heparin anticoagulants (danaparoid, argatroban, fondaparinux and bivalirudin) used to treat HIT should be given in therapeutic rather than prophylactic doses. Direct oral anticoagulants may be used in place of warfarin after patients with HIT have responded to alternative parenteral anticoagulants with platelet count recovery. CHANGES IN MANAGEMENT AS A RESULT OF THIS STATEMENT: These are the first Australasian recommendations for diagnosis and management of HIT, with a focus on locally available diagnostic assays and therapeutic options. The importance of examining both clinical and laboratory data in considering a diagnosis of HIT cannot be overstated.


Assuntos
Anticoagulantes/efeitos adversos , Heparina/efeitos adversos , Trombocitopenia/diagnóstico , Trombocitopenia/tratamento farmacológico , Anticoagulantes/uso terapêutico , Austrália , Consenso , Hemorragia/induzido quimicamente , Heparina/imunologia , Humanos , Nova Zelândia , Fator Plaquetário 4/imunologia , Receptores de IgG/imunologia , Trombocitopenia/induzido quimicamente , Trombose/etiologia
6.
BMC Evol Biol ; 18(1): 77, 2018 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-29843598

RESUMO

BACKGROUND: Understanding genomic and phenotypic diversity among cryptic pest taxa has important implications for the management of pests and diseases. The diamondback moth, Plutella xylostella L., has been intensively studied due to its ability to evolve insecticide resistance and status as the world's most destructive pest of brassicaceous crops. The surprise discovery of a cryptic species endemic to Australia, Plutella australiana Landry & Hebert, raised questions regarding the distribution, ecological traits and pest status of the two species, the capacity for gene flow and whether specific management was required. Here, we collected Plutella from wild and cultivated brassicaceous plants from 75 locations throughout Australia and screened 1447 individuals to identify mtDNA lineages and Wolbachia infections. We genotyped genome-wide SNP markers using RADseq in coexisting populations of each species. In addition, we assessed reproductive compatibility in crossing experiments and insecticide susceptibility phenotypes using bioassays. RESULTS: The two Plutella species coexisted on wild brassicas and canola crops, but only 10% of Plutella individuals were P. australiana. This species was not found on commercial Brassica vegetable crops, which are routinely sprayed with insecticides. Bioassays found that P. australiana was 19-306 fold more susceptible to four commonly-used insecticides than P. xylostella. Laboratory crosses revealed that reproductive isolation was incomplete but directionally asymmetric between the species. However, genome-wide nuclear SNPs revealed striking differences in genetic diversity and strong population structure between coexisting wild populations of each species. Nuclear diversity was 1.5-fold higher in P. australiana, yet both species showed limited variation in mtDNA. Infection with a single Wolbachia subgroup B strain was fixed in P. australiana, suggesting that a selective sweep contributed to low mtDNA diversity, while a subgroup A strain infected just 1.5% of P. xylostella. CONCLUSIONS: Despite sympatric distributions and the capacity to hybridize, strong genomic and phenotypic divergence exists between these Plutella species that is consistent with contrasting colonization histories and reproductive isolation after secondary contact. Although P. australiana is a potential pest of brassicaceous crops, it is of secondary importance to P. xylostella.


Assuntos
Variação Genética , Hibridização Genética , Mariposas/genética , Animais , Austrália , Bioensaio , Cruzamentos Genéticos , DNA Mitocondrial/genética , Feminino , Fertilidade , Genética Populacional , Geografia , Haplótipos/genética , Heterozigoto , Hibridização Genética/efeitos dos fármacos , Resistência a Inseticidas/efeitos dos fármacos , Resistência a Inseticidas/genética , Inseticidas/toxicidade , Funções Verossimilhança , Masculino , Mitocôndrias/genética , Mariposas/microbiologia , Filogenia , Especificidade da Espécie , Simpatria , Wolbachia/efeitos dos fármacos , Wolbachia/fisiologia
7.
Platelets ; 29(8): 793-800, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29090586

RESUMO

MYH9-related disorders (MYH9-RDs) caused by mutation of the MYH9 gene which encodes non-muscle myosin heavy-chain-IIA (NMMHC-IIA), an important motor protein in hemopoietic cells, are the most commonly encountered cause of inherited macrothrombocytopenia. Despite distinguishing features including an autosomal dominant mode of inheritance, giant platelets on the peripheral blood film accompanied by leucocytes with cytoplasmic inclusion bodies (döhle-like bodies), these disorders remain generally under-recognized and often misdiagnosed as immune thrombocytopenia (ITP). This may result in inappropriate treatment with corticosteroids, immunosupressants and in some cases, splenectomy. We explored the efficacy of next generation sequencing (NGS) with a candidate gene panel to establish the aetiology of thrombocytopenia for individuals who had been referred to our center from hematologists in the Australasian region in whom the cause of thrombocytopenia was suspected to be secondary to an inherited condition but which remained uncharacterized despite phenotypic investigations. Pathogenic MYH9 variants were detected in 15 (15/121, 12.4%) individuals and the pathogenecity of a novel variant of uncertain significance was confirmed in a further two related individuals following immunofluorescence (IF) staining performed in our laboratory. Concerningly, only one (1/17) individual diagnosed with MYH9-RD had been referred with this as a presumptive diagnosis, in all other cases (16/17, 94.1%), a diagnosis was not suspected by referring clinicians, indicating a lack of awareness or a failing of our diagnostic approach to these conditions. We examined the mean platelet diameter (MPD) measurements as a means to better identify and quantify platelet size. MPDs in cases with MYH9-RDs were significantly larger than controls (p < 0.001) and in 91% were greater than a previously suggested threshold for platelets in cases of ITP. In addition, we undertook IF staining in a proportion of cases and confirm that this test and/or NGS are satisfactory diagnostic tests. We propose that fewer cases of MYH9-RDs would be missed if diagnostic algorithms prioritized IF and/or NGS in cases of thrombocytopenia associated with giant platelets, even if döhle-like bodies are not appreciated on the peripheral blood film. Finally, our report describes the long-term use of a thrombopoietin agonist in a case of MYH9-RD that had previously been diagnosed as ITP, and demonstrates that treatment with these agents may be possible, and is well tolerated, in this group of patients.


Assuntos
Plaquetas/metabolismo , Perda Auditiva Neurossensorial/genética , Mutação , Cadeias Pesadas de Miosina/genética , Púrpura Trombocitopênica Idiopática/genética , Receptores Fc/uso terapêutico , Proteínas Recombinantes de Fusão/uso terapêutico , Trombocitopenia/congênito , Trombopoetina/uso terapêutico , Adulto , Australásia , Plaquetas/efeitos dos fármacos , Plaquetas/patologia , Tamanho Celular , Estudos de Coortes , Diagnóstico Diferencial , Feminino , Expressão Gênica , Perfilação da Expressão Gênica , Genes Dominantes , Perda Auditiva Neurossensorial/sangue , Perda Auditiva Neurossensorial/diagnóstico , Perda Auditiva Neurossensorial/tratamento farmacológico , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Corpos de Inclusão/efeitos dos fármacos , Corpos de Inclusão/metabolismo , Corpos de Inclusão/patologia , Masculino , Volume Plaquetário Médio , Pessoa de Meia-Idade , Cadeias Pesadas de Miosina/sangue , Púrpura Trombocitopênica Idiopática/sangue , Púrpura Trombocitopênica Idiopática/diagnóstico , Púrpura Trombocitopênica Idiopática/tratamento farmacológico , Trombocitopenia/sangue , Trombocitopenia/diagnóstico , Trombocitopenia/tratamento farmacológico , Trombocitopenia/genética
8.
Blood ; 126(17): 2027-30, 2015 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-26316623

RESUMO

Hemizygous deletion of a variable region on chromosome 11q containing FLI1 causes an inherited platelet-related bleeding disorder in Paris-Trousseau thrombocytopenia and Jacobsen syndrome. These multisystem disorders are also characterized by heart anomalies, changes in facial structure, and intellectual disability. We have identified a consanguineous family with autosomal recessive inheritance of a bleeding disorder that mimics Paris-Trousseau thrombocytopenia but has no other features of the 11q23 deletion syndrome. Affected individuals in this family have moderate thrombocytopenia; absent collagen-induced platelet aggregation; and large, fused α-granules in 1% to 5% of circulating platelets. This phenotype was caused by a FLI1 homozygous c.970C>T-point mutation that predicts an arginine-to-tryptophan substitution in the conserved ETS DNA-binding domain of FLI1. This mutation caused a transcription defect at the promoter of known FLI1 target genes GP6, GP9, and ITGA2B, as measured by luciferase assay in HEK293 cells, and decreased the expression of these target proteins in affected members of the family as measured by Western blotting of platelet lysates. This kindred suggests abnormalities in FLI1 as causative of Paris-Trousseau thrombocytopenia and confirms the important role of FLI1 in normal platelet development.


Assuntos
Cromossomos Humanos Par 11/genética , DNA/metabolismo , Síndrome da Deleção Distal 11q de Jacobsen/genética , Mutação/genética , Proteína Proto-Oncogênica c-fli-1/genética , Sequência de Aminoácidos , Feminino , Seguimentos , Genes Recessivos , Células HEK293 , Humanos , Síndrome da Deleção Distal 11q de Jacobsen/metabolismo , Síndrome da Deleção Distal 11q de Jacobsen/patologia , Masculino , Dados de Sequência Molecular , Linhagem , Fenótipo , Prognóstico , Proteína Proto-Oncogênica c-fli-1/metabolismo , Homologia de Sequência de Aminoácidos
9.
Platelets ; 28(8): 799-811, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28277064

RESUMO

GluN1 is a mandatory component of N-methyl-D-aspartate receptors (NMDARs) best known for their roles in the brain, but with increasing evidence for relevance in peripheral tissues, including platelets. Certain anti-GluN1 antibodies reduce brain infarcts in rodent models of ischaemic stroke. There is also evidence that human anti-GluN1 autoantibodies reduce neuronal damage in stroke patients, but the underlying mechanism is unclear. This study investigated whether anti-GluN1-mediated neuroprotection involves inhibition of platelet function. Four commercial anti-GluN1 antibodies were screened for their abilities to inhibit human platelet aggregation. Haematological parameters were examined in rats vaccinated with GluN1. Platelet effects of a mouse monoclonal antibody targeting the glycine-binding region of GluN1 (GluN1-S2) were tested in assays of platelet activation, aggregation and thrombus formation. The epitope of anti-GluN1-S2 was mapped and the mechanism of antibody action modelled using crystal structures of GluN1. Our work found that rats vaccinated with GluN1 had a mildly prolonged bleeding time and carried antibodies targeting mostly GluN1-S2. The monoclonal anti-GluN1-S2 antibody (from BD Biosciences) inhibited activation and aggregation of human platelets in the presence of adrenaline, adenosine diphosphate, collagen, thrombin and a protease-activated receptor 1-activating peptide. When human blood was flowed over collagen-coated surfaces, anti-GluN1-S2 impaired thrombus growth and stability. The epitope of anti-GluN1-S2 was mapped to α-helix H located within the glycine-binding clamshell of GluN1, where the antibody binding was computationally predicted to impair opening of the NMDAR channel. Our results indicate that anti-GluN1-S2 inhibits function of human platelets, including dense granule release and thrombus growth. Findings add to the evidence that platelet NMDARs regulate thrombus formation and suggest a novel mechanism by which anti-GluN1 autoantibodies limit stroke-induced neuronal damage.


Assuntos
Autoanticorpos/sangue , Plaquetas/metabolismo , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Trombose/genética , Animais , Humanos , Masculino , Ratos , Ratos Wistar
10.
Semin Thromb Hemost ; 41(3): 315-22, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25703517

RESUMO

Hypercoagulability plays a key role in the progression of cardiovascular disease (CVD). Although omega-3 polyunsaturated fatty acid (PUFA) intake has been inversely related to the risk of cardiovascular events, the mechanisms are not fully understood. The aim of this study was to investigate the effects of omega-3 on novel markers of global coagulation. The generation of fibrin and thrombin, measured via overall hemostasis potential (OHP) assay and calibrated automated thrombography, respectively, was determined in 40 healthy subjects and 16 patients with CVD at baseline and after 4 weeks of 640 mg/day omega-3 PUFA. In healthy subjects, fibrin generation was significantly reduced, as measured by overall coagulation potential (p = 0.013), OHP (p < 0.001), velocity of fibrin polymerization (p = 0.002), and significant increase in delay to fibrin generation (p = 0.002). The peak of generated thrombin was significantly reduced (p = 0.043). In subjects with CVD, omega-3 PUFA significantly reduced OHP and significantly increased the lag time to thrombin generation (both p < 0.001). Treatment with omega-3 PUFA had no effect on other fibrin and thrombin generation parameters in CVD patients. Four-week omega-3 PUFA supplementation reduced thrombotic potential in healthy subjects, as shown by reduced fibrin generation and peak thrombin. There was a greater effect on fibrin generation in healthy subjects compared with those with CVD.


Assuntos
Doenças Cardiovasculares/tratamento farmacológico , Ácidos Graxos Ômega-3/uso terapêutico , Fibrina/química , Trombina/química , Adulto , Idoso , Idoso de 80 Anos ou mais , Coagulação Sanguínea , Plaquetas/efeitos dos fármacos , Estudos de Casos e Controles , Colesterol/química , Feminino , Fibrinólise , Humanos , Masculino , Pessoa de Meia-Idade , Trombose/patologia , Adulto Jovem
11.
Stem Cells ; 32(11): 2869-79, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25074424

RESUMO

Mouse embryonic stem cells (mESCs) and epiblast stem cells represent the naïve and primed pluripotent states, respectively. These cells self-renew via distinct signaling pathways and can transition between the two states in the presence of appropriate growth factors. Manipulation of signaling pathways has therefore allowed the isolation of novel pluripotent cell types such as Fibroblast growth factor, Activin and BIO-derived stem cells and IESCs. However, the effect of cell seeding density on pluripotency remains unexplored. In this study, we have examined whether mESCs can epigenetically regulate E-cadherin to enter a primed-like state in response to low cell seeding density. We show that low density seeding in the absence of leukaemia inhibitory factor (LIF) induces decreased apoptosis and maintenance of pluripotency via Activin/Nodal, concomitant with loss of E-cadherin, Signal transducer and activator of transcription phosphorylation, and chimera-forming ability. These cells, E-cadherin negative proliferating stem cells (ENPSCs) can be reverted to a naïve phenotype by addition of LIF or forced E-cadherin expression. However, prolonged culture of ENPSCs without LIF leads to methylation of the E-cadherin promoter (ENPSC(M)), which cannot be reversed by LIF supplementation, and increased histone H3K27 and decreased H3K4 trimethylation. Transcript analysis of ENPSC(M) revealed a primed-like phenotype and their differentiation leads to enrichment of neuroectoderm cells. The generation of ENPSCs is similar to tumorigenesis as ENPSCs exhibit transcript alterations associated with neoplasia, hyperplasia, carcinoma, and metastasis. We therefore describe a novel cell model to elucidate the role of E-cadherin in pluripotency and to investigate epigenetic regulation of this gene during mESC differentiation and tumor metastasis.


Assuntos
Caderinas/metabolismo , Diferenciação Celular/fisiologia , Metilação de DNA , Células-Tronco Embrionárias/metabolismo , Células-Tronco Pluripotentes/citologia , Regiões Promotoras Genéticas , Transdução de Sinais/fisiologia , Animais , Separação Celular , Células Cultivadas , Epigênese Genética/efeitos dos fármacos , Humanos , Fator Inibidor de Leucemia/metabolismo , Camundongos da Linhagem 129 , Células-Tronco Pluripotentes/metabolismo
12.
Blood ; 119(18): 4311-20, 2012 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-22431567

RESUMO

Ligand-induced ectodomain shedding of glycoprotein VI (GPVI) is a metalloproteinase-dependent event. We examined whether shear force, in the absence of GPVI ligand, was sufficient to induce shedding of GPVI. Human-citrated platelet-rich plasma or washed platelets were subjected to increasing shear rates in a cone-plate viscometer, and levels of intact and cleaved GPVI were examined by Western blot and ELISA. Pathophysiologic shear rates (3000-10 000 seconds(-1)) induced platelet aggregation and metalloproteinase-dependent appearance of soluble GPVI ectodomain, and GPVI platelet remnant. Shedding of GPVI continued after transient exposure to shear. Blockade of α(IIb)ß(3), GPIbα, or intracellular signaling inhibited shear-induced platelet aggregation but minimally affected shear-induced shedding of GPVI. Shear-induced GPVI shedding also occurred in platelet-rich plasma or washed platelets isolated from a von Willebrand disease type 3 patient with no detectable VWF, implying that shear-induced activation of platelet metalloproteinases can occur in the absence of GPVI and GPIbα ligands. Significantly elevated levels of sGPVI were observed in 10 patients with stable angina pectoris, with well-defined single vessel coronary artery disease and mean intracoronary shear estimates at 2935 seconds(-1) (peak shear, 19 224 seconds(-1)). Loss of GPVI in platelets exposed to shear has potential implications for the stability of a forming thrombus at arterial shear rates.


Assuntos
Plaquetas/química , Estenose Coronária/sangue , Hemorreologia , Glicoproteínas da Membrana de Plaquetas/química , Estresse Mecânico , Proteínas ADAM/antagonistas & inibidores , Proteínas ADAM/fisiologia , Proteína ADAM10 , Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Secretases da Proteína Precursora do Amiloide/fisiologia , Angina Estável/sangue , Viscosidade Sanguínea , Colágeno/fisiologia , Estenose Coronária/genética , Dipeptídeos/farmacologia , Regulação para Baixo , Feminino , Humanos , Ácidos Hidroxâmicos/farmacologia , Glicoproteínas de Membrana/fisiologia , Proteínas de Membrana/antagonistas & inibidores , Proteínas de Membrana/fisiologia , Pessoa de Meia-Idade , Agregação Plaquetária , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/fisiologia , Complexo Glicoproteico GPIb-IX de Plaquetas , Glicoproteínas da Membrana de Plaquetas/biossíntese , Glicoproteínas da Membrana de Plaquetas/genética , Plasma Rico em Plaquetas , Estrutura Terciária de Proteína , Doença de von Willebrand Tipo 3/sangue
13.
Nucleic Acids Res ; 40(9): 3990-4001, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22223247

RESUMO

The regulation of gene expression is central to developmental programs and largely depends on the binding of sequence-specific transcription factors with cis-regulatory elements in the genome. Hox transcription factors specify the spatial coordinates of the body axis in all animals with bilateral symmetry, but a detailed knowledge of their molecular function in instructing cell fates is lacking. Here, we used chromatin immunoprecipitation with massively parallel sequencing (ChIP-seq) to identify Hoxa2 genomic locations in a time and space when it is actively instructing embryonic development in mouse. Our data reveals that Hoxa2 has large genome coverage and potentially regulates thousands of genes. Sequence analysis of Hoxa2-bound regions identifies high occurrence of two main classes of motifs, corresponding to Hox and Pbx-Hox recognition sequences. Examination of the binding targets of Hoxa2 faithfully captures the processes regulated by Hoxa2 during embryonic development; in addition, it uncovers a large cluster of potential targets involved in the Wnt-signaling pathway. In vivo examination of canonical Wnt-ß-catenin signaling reveals activity specifically in Hoxa2 domain of expression, and this is undetectable in Hoxa2 mutant embryos. The comprehensive mapping of Hoxa2-binding sites provides a framework to study Hox regulatory networks in vertebrate developmental processes.


Assuntos
Desenvolvimento Embrionário/genética , Proteínas de Homeodomínio/metabolismo , Via de Sinalização Wnt/genética , Animais , Sítios de Ligação , Região Branquial/metabolismo , Imunoprecipitação da Cromatina , Genoma , Sequenciamento de Nucleotídeos em Larga Escala , Proteínas de Homeodomínio/genética , Camundongos , Análise de Sequência de DNA , beta Catenina/metabolismo
14.
Semin Thromb Hemost ; 39(1): 25-32, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23329646

RESUMO

Hyperactivation and aggregation of platelets play a major role in thrombosis and hemostasis. The aims of this study were to investigate the effects of omega-3 polyunsaturated fatty acids (PUFAs) on platelet function. Light transmission aggregometry and flow cytometric analyses of platelet activation and platelet-leukocyte aggregates were determined at baseline and after 4 weeks of omega-3 (docosahexaenoic acid 520 mg and eicosapentaenoic acid 120 mg) supplementation. In total, 40 healthy subjects and 16 patients with a history of cardiovascular disease (CVD) completed the study. In healthy subjects, omega-3 PUFA significantly reduced adenosine diphosphate (ADP)-induced (maximum amplitude, 77.0% ± 3.2% vs. 71.6% ± 3.4%, p = 0.036; maximum slope, 86.3 ± 1.8 vs. 80.7 ± 2.1, p = 0.014) and adrenaline-induced platelet aggregation (maximum slope, 42.8 ± 2.7 vs. 37.4 ± 3.0, p = 0.013; lag time, 00:21 ± 00:02 vs. 00:31 ± 00:03 s, p = 0.002). Omega-3 PUFA also reduced P-selectin expression (40.5% ± 2.9% vs. 34.4% ± 2.4%, p = 0.049) on platelets and platelet-monocyte aggregates (38.5% ± 2.6% vs. 31.4% ± 2.5%, p = 0.022) after activation with ADP 0.5 µM. There were fewer changes in platelet aggregation and activation found in subjects with CVD. Nevertheless, there was a reduction in the slope of arachidonic acid-induced platelet aggregation (13.21 ± 6.41 vs. 4.88 ± 3.01, p = 0.009) and increased lag time for U46619 (00:16 ± 00:00 vs. 00:29 ± 00:07 s, p = 0.018) induced platelet aggregation. Thus, 4-week supplementation of 640 mg omega-3 PUFA reduced measures of platelet aggregation and activation in healthy subjects but effects were less evident in patients with existing CVD. Our findings support the recommendation that the omega-3 PUFA dose be higher in CVD than among healthy subjects.


Assuntos
Plaquetas/efeitos dos fármacos , Doenças Cardiovasculares/sangue , Suplementos Nutricionais , Ácidos Graxos Ômega-3/farmacologia , Difosfato de Adenosina/farmacologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Plaquetas/fisiologia , Ácidos Docosa-Hexaenoicos/administração & dosagem , Ácidos Docosa-Hexaenoicos/farmacologia , Relação Dose-Resposta a Droga , Esquema de Medicação , Ácido Eicosapentaenoico/administração & dosagem , Ácido Eicosapentaenoico/farmacologia , Epinefrina/farmacologia , Ácidos Graxos Ômega-3/administração & dosagem , Humanos , Pessoa de Meia-Idade , Ativação Plaquetária/efeitos dos fármacos , Agregação Plaquetária/efeitos dos fármacos , Adulto Jovem
15.
Stem Cells ; 30(9): 1842-51, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22696497

RESUMO

We have recently shown that loss of E-cadherin in mouse embryonic stem cells (mESCs) results in significant alterations to both the transcriptome and hierarchy of pluripotency-associated signaling pathways. Here, we show that E-cadherin promotes kruppel-like factor 4 (Klf4) and Nanog transcript and protein expression in mESCs via STAT3 phosphorylation and that ß-catenin, and its binding region in E-cadherin, is required for this function. To further investigate the role of E-cadherin in leukemia inhibitory factor (LIF)-dependent pluripotency, E-cadherin null (Ecad(-/-)) mESCs were cultured in LIF/bone morphogenetic protein supplemented medium. Under these conditions, Ecad(-/-) mESCs exhibited partial restoration of cell-cell contact and STAT3 phosphorylation and upregulated Klf4, Nanog, and N-cadherin transcripts and protein. Abrogation of N-cadherin using an inhibitory peptide caused loss of phospho STAT3, Klf4, and Nanog in these cells, demonstrating that N-cadherin supports LIF-dependent pluripotency in this context. We therefore identify a novel molecular mechanism linking E- and N-cadherin to the core circuitry of pluripotency in mESCs. This mechanism may explain the recently documented role of E-cadherin in efficient induced pluripotent stem cell reprogramming.


Assuntos
Caderinas/metabolismo , Células-Tronco Embrionárias/metabolismo , Proteínas de Homeodomínio/biossíntese , Fator de Transcrição STAT3/metabolismo , Animais , Diferenciação Celular , Processos de Crescimento Celular/fisiologia , Células Cultivadas , Proteínas de Homeodomínio/metabolismo , Células-Tronco Pluripotentes Induzidas , Fator 4 Semelhante a Kruppel , Fatores de Transcrição Kruppel-Like/metabolismo , Camundongos , Proteína Homeobox Nanog , Fosforilação , Transdução de Sinais , Transfecção
16.
Thorax ; 67(7): 639-44, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22334531

RESUMO

INTRODUCTION: Obstructive sleep apnoea (OSA) is associated with increased cardiovascular risk, however the mechanisms are not well established. OBJECTIVES: This study aimed to determine whether treatment of OSA with nasal continuous positive airway pressure (CPAP) would favourably alter coagulability across the sleep-wake cycle. METHODS: In a randomised crossover trial, 28 patients received therapeutic or placebo CPAP, each for 2 months with a 1 month washout between treatments. After each treatment period, a 24 h coagulation study was conducted in the laboratory. Plasminogen activator inhibitor-1 (PAI-1), D-dimer, fibrinogen, von Willebrand Factor (vWF), factor VIII (FVIII), factor VII (FVII) and factor V (FV) were determined at seven time points over the day and night. RESULTS: At baseline, patients had severe OSA (Apnoea Hypopnoea Index 37.9 ± 23.9 events/h). Treatment of OSA with CPAP compared with placebo resulted in lower 24 h levels of vWF (-3.9%, p=0.013), FVIII (-6.2%, p=0.007) and FV (-4.2%, p<0.001). The greatest difference occurred during the nocturnal and early morning periods. In contrast, fibrinogen, D-dimer, FVII and PAI-1 did not differ between treatments, however all markers displayed diurnal variability independent of treatment. CONCLUSIONS: In this randomised, placebo-controlled crossover trial, treatment of OSA with CPAP reduced the early morning level of vWF, and nocturnal levels of FVIII and FV. These findings suggest that CPAP may reduce cardiovascular risk in OSA, in part through reducing risk of thrombosis.


Assuntos
Coagulação Sanguínea , Pressão Positiva Contínua nas Vias Aéreas , Apneia Obstrutiva do Sono/terapia , Estudos Cross-Over , Feminino , Produtos de Degradação da Fibrina e do Fibrinogênio/metabolismo , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Inibidor 1 de Ativador de Plasminogênio/sangue , Estudos Prospectivos , Fatores de Risco , Apneia Obstrutiva do Sono/sangue , Resultado do Tratamento , Fator de von Willebrand/metabolismo
17.
Stem Cells ; 29(4): 629-40, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21308866

RESUMO

Mouse embryonic stem (mES) cells express a low sulfated form of heparan sulfate (HS). HS chains displayed by ES cells and their progeny become more complex and more sulfated during progression from pluripotency to neuroectodermal precursors. Sulfated epitopes are important for recognition and binding of a variety of ligands including members of the fibroblast growth factor (FGF) family. We demonstrated previously that mES cells lacking HS cannot undergo neural specification but this activity can be recovered by adding soluble heparin, a highly sulfated glycosaminoglycan (GAG). Therefore, we hypothesized that soluble GAGs might be used to support neural differentiation of HS competent cells and that the mechanisms underlying this activity might provide useful information about the signaling pathways critical for loss of pluripotency and early lineage commitment. In this study, we demonstrate that specific HS/heparin polysaccharides support formation of Sox1(+) neural progenitor cells from wild-type ES cells. This effect is dependent on sulfation pattern, concentration, and length of saccharide. Using a selective inhibitor of FGF signal transduction, we show that heparin modulates signaling events regulating exit from pluripotency and commitment to primitive ectoderm and subsequently neuroectoderm. Interestingly, we were also able to demonstrate that multiple receptor tyrosine kinases were influenced by HS in this system. This suggests roles for additional factors, possibly in cell proliferation or protection from apoptosis, during the process of neural specification. Therefore, we conclude that soluble GAGs or synthetic mimics could be considered as suitable low-cost factors for addition to ES cell differentiation regimes.


Assuntos
Células-Tronco Embrionárias/citologia , Células-Tronco Embrionárias/metabolismo , Glicosaminoglicanos/metabolismo , Proteoglicanas de Heparan Sulfato/metabolismo , Células-Tronco Neurais/citologia , Células-Tronco Neurais/metabolismo , Animais , Diferenciação Celular , MAP Quinases Reguladas por Sinal Extracelular/análise , MAP Quinases Reguladas por Sinal Extracelular/biossíntese , Fatores de Crescimento de Fibroblastos/antagonistas & inibidores , Fatores de Crescimento de Fibroblastos/metabolismo , Citometria de Fluxo , Técnicas de Inativação de Genes , Camundongos , N-Acetilglucosaminiltransferases/genética , Placa Neural/embriologia , RNA Interferente Pequeno , Receptores Proteína Tirosina Quinases/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Transcrição SOXB1/biossíntese , Transdução de Sinais
19.
Res Pract Thromb Haemost ; 6(6): e12792, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36186101

RESUMO

Background: In Australia, prescribing restrictions limit access to internationally recommended second-line therapies such as rituximab and thrombopoietin agonists (TPO-A) (eltrombopag and romiplostim). Subsequent lines of therapy include an array of immunosuppressive and immune-modulating agents directed by drug availability and physician and patient preference. Objectives: The objective of the study was to describe the use of first and subsequent lines of treatment for adult immune thrombocytopenia (ITP) in Australia and to assess their effectiveness and tolerability. Patients/Methods: A retrospective review of medical records was conducted of 322 patients treated for ITP at eight participating centers in Australia between 2013 and 2020. Data were analyzed by descriptive statistics and frequency distribution using pivot tables, and comparisons between centers were assessed using paired t tests. Results: Mean age at diagnosis of ITP was 48.8 years (standard deviation [SD], 22.6) and 58.3% were women. Primary ITP was observed in 72% and secondary ITP in 28% of the patients; 95% of patients received first-line treatment with prednisolone (76%), dexamethasone (15%), or intravenous immunoglobulin (48%) alone or in combination. Individuals with secondary ITP were less steroid dependent (72% vs. 76%) and required less treatment with a second-line agent (47% vs. 58%) in the study sample. Over half (56%) of the cohort received treatment with one or more second-line agents. The mean number of second-line agents used for each patient was 1.9 (SD, 1.2). The most used second-line therapy was rituximab, followed by etrombopag and splenectomy. These also generated the highest rates of complete response (60.3%, 72.1%, and 71.8% respectively). The most unfavorable side effect profiles were seen in long-term corticosteroids and splenectomy. Conclusion: A wide range of "second-line" agents were used across centers with variable response rates and side effect profiles. Findings suggest greater effectiveness of rituximab and TPO-A, supporting their use earlier in the treatment course of patients with ITP across Australia.

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