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1.
Nucleic Acids Res ; 50(19): e112, 2022 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-35979952

RESUMO

The assessment of transcriptome-wide ribosome binding to mRNAs is useful for studying the dynamic regulation of protein synthesis. Two methods frequently applied in eukaryotic cells that operate at different levels of resolution are polysome profiling, which reveals the distribution of ribosome loads across the transcriptome, and ribosome footprinting (also termed ribosome profiling or Ribo-Seq), which when combined with appropriate data on mRNA expression can reveal ribosome densities on individual transcripts. In this study we develop methods for relating the information content of these two methods to one another, by reconstructing theoretical polysome profiles from ribosome footprinting data. Our results validate both approaches as experimental tools. Although we show that both methods can yield highly consistent data, some published ribosome footprinting datasets give rise to reconstructed polysome profiles with non-physiological features. We trace these aberrant features to inconsistencies in RNA and Ribo-Seq data when compared to datasets yielding physiological polysome profiles, thereby demonstrating that modelled polysomes are useful for assessing global dataset properties such as its quality in a simple, visual approach. Aside from using polysome profile reconstructions on published datasets, we propose that this also provides a useful tool for validating new ribosome footprinting datasets in early stages of analyses.


Assuntos
Biossíntese de Proteínas , Ribossomos , Ribossomos/genética , Ribossomos/metabolismo , Polirribossomos/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Transcriptoma
2.
Sci Rep ; 11(1): 19842, 2021 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-34615897

RESUMO

Human genetic studies have linked rare coding variants in microglial genes, such as TREM2, and more recently PLCG2 to Alzheimer's disease (AD) pathology. The P522R variant in PLCG2 has been shown to confer protection for AD and to result in a subtle increase in enzymatic activity. PLCγ2 is a key component of intracellular signal transduction networks and induces Ca2+ signals downstream of many myeloid cell surface receptors, including TREM2. To explore the relationship between PLCγ2 and TREM2 and the role of PLCγ2 in regulating immune cell function, we generated human induced pluripotent stem cell (iPSC)- derived macrophages from isogenic lines with homozygous PLCG2 knockout (Ko). Stimulating TREM2 signalling using a polyclonal antibody revealed a complete lack of calcium flux and IP1 accumulation in PLCγ2 Ko cells, demonstrating a non-redundant role of PLCγ2 in calcium release downstream of TREM2. Loss of PLCγ2 led to broad changes in expression of several macrophage surface markers and phenotype, including reduced phagocytic activity and survival, while LPS-induced secretion of the inflammatory cytokines TNFα and IL-6 was unaffected. We identified additional deficits in PLCγ2- deficient cells that compromised cellular adhesion and migration. Thus, PLCγ2 is key in enabling divergent cellular functions and might be a promising target to increase beneficial microglial functions.


Assuntos
Células-Tronco Pluripotentes Induzidas/metabolismo , Integrinas/metabolismo , Macrófagos/metabolismo , Glicoproteínas de Membrana/metabolismo , Fosfolipase C gama/metabolismo , Receptores Imunológicos/metabolismo , Transdução de Sinais , Biomarcadores , Cálcio/metabolismo , Adesão Celular/genética , Movimento Celular/genética , Citocinas/metabolismo , Matriz Extracelular , Técnicas de Silenciamento de Genes , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Mediadores da Inflamação/metabolismo , Macrófagos/citologia , Glicoproteínas de Membrana/genética , Fagocitose , Fosfolipase C gama/genética , Receptores Imunológicos/genética
3.
Structure ; 29(11): 1241-1252.e5, 2021 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-34233201

RESUMO

Mutations in TREM2, a receptor expressed by microglia in the brain, are associated with an increased risk of neurodegeneration, including Alzheimer's disease. Numerous studies support a role for TREM2 in sensing damaging stimuli and triggering signaling cascades necessary for neuroprotection. Despite its significant role, ligands and regulators of TREM2 activation, and the mechanisms governing TREM2-dependent responses and its cleavage from the membrane, remain poorly characterized. Here, we present phage display generated antibody single-chain variable fragments (scFvs) to human TREM2 immunoglobulin-like domain. Co-crystal structures revealed the binding of two scFvs to an epitope on the TREM2 domain distal to the putative ligand-binding site. Enhanced functional activity was observed for oligomeric scFv species, which inhibited the production of soluble TREM2 in a HEK293 cell model. We hope that detailed characterization of their epitopes and properties will facilitate the use of these renewable binders as structural and functional biology tools for TREM2 research.


Assuntos
Epitopos/metabolismo , Glicoproteínas de Membrana/metabolismo , Receptores Imunológicos/metabolismo , Células HEK293 , Humanos , Fagocitose/fisiologia , Anticorpos de Cadeia Única
4.
Chem Sci ; 12(10): 3768-3785, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34163650

RESUMO

Amyloid ß oligomers (Aßo) are the main toxic species in Alzheimer's disease, which have been targeted for single drug treatment with very little success. In this work we report a new approach for identifying functional Aßo binding compounds. A tailored library of 971 fluorine containing compounds was selected by a computational method, developed to generate molecular diversity. These compounds were screened for Aßo binding by a combined 19F and STD NMR technique. Six hits were evaluated in three parallel biochemical and functional assays. Two compounds disrupted Aßo binding to its receptor PrPC in HEK293 cells. They reduced the pFyn levels triggered by Aßo treatment in neuroprogenitor cells derived from human induced pluripotent stem cells (hiPSC). Inhibitory effects on pTau production in cortical neurons derived from hiPSC were also observed. These drug-like compounds connect three of the pillars in Alzheimer's disease pathology, i.e. prion, Aß and Tau, affecting three different pathways through specific binding to Aßo and are, indeed, promising candidates for further development.

5.
Mol Neurodegener ; 16(1): 22, 2021 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-33823896

RESUMO

The central role of the resident innate immune cells of the brain (microglia) in neurodegeneration has become clear over the past few years largely through genome-wide association studies (GWAS), and has rapidly become an active area of research. However, a mechanistic understanding (gene to function) has lagged behind. That is now beginning to change, as exemplified by a number of recent exciting and important reports that provide insight into the function of two key gene products - TREM2 (Triggering Receptor Expressed On Myeloid Cells 2) and PLCγ2 (Phospholipase C gamma2) - in microglia, and their role in neurodegenerative disorders. In this review we explore and discuss these recent advances and the opportunities that they may provide for the development of new therapies.


Assuntos
Doença de Alzheimer/imunologia , Células do Tecido Conjuntivo/metabolismo , Linfócitos/metabolismo , Glicoproteínas de Membrana/fisiologia , Microglia/metabolismo , Células Mieloides/metabolismo , Fosfolipase C gama/fisiologia , Receptores Imunológicos/fisiologia , Transdução de Sinais/fisiologia , Idade de Início , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/genética , Doença de Alzheimer/prevenção & controle , Humanos , Metabolismo dos Lipídeos , Glicoproteínas de Membrana/química , Microglia/fisiologia , Modelos Moleculares , Mutação , Fosfolipase C gama/química , Fosfolipase C gama/genética , Conformação Proteica , Domínios Proteicos , Mapeamento de Interação de Proteínas , Receptores Imunológicos/química , Homologia de Sequência de Aminoácidos , Relação Estrutura-Atividade
6.
Alzheimers Res Ther ; 12(1): 151, 2020 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-33198789

RESUMO

BACKGROUND: TREM2 is a microglial cell surface receptor, with risk mutations linked to Alzheimer's disease (AD), including R47H. TREM2 signalling via SYK aids phagocytosis, chemotaxis, survival, and changes to microglial activation state. In AD mouse models, knockout (KO) of TREM2 impairs microglial clustering around amyloid and prevents microglial activation. The R47H mutation is proposed to reduce TREM2 ligand binding. We investigated cell phenotypes of the R47H mutant and TREM2 KO in a model of human microglia, and compared their transcriptional signatures, to determine the mechanism by which R47H TREM2 disrupts function. METHODS: We generated human microglia-like iPSC-macrophages (pMac) from isogenic induced pluripotent stem cell (iPSC) lines, with homozygous R47H mutation or TREM2 knockout (KO). We firstly validated the effect of the R47H mutant on TREM2 surface and subcellular localization in pMac. To assess microglial phenotypic function, we measured phagocytosis of dead neurons, cell morphology, directed migration, survival, and LPS-induced inflammation. We performed bulk RNA-seq, comparing significant differentially expressed genes (DEGs; p < 0.05) between the R47H and KO versus WT, and bioinformatically predicted potential upstream regulators of TREM2-mediated gene expression. RESULTS: R47H modified surface expression and shedding of TREM2, but did not impair TREM2-mediated signalling, or gross phenotypes that were dysregulated in the TREM2 KO (phagocytosis, motility, survival). However, altered gene expression in the R47H TREM2 pMac overlapped by 90% with the TREM2 KO and was characterised by dysregulation of genes involved with immunity, proliferation, activation, chemotaxis, and adhesion. Downregulated mediators of ECM adhesion included the vitronectin receptor αVß3, and consequently, R47H TREM2 pMac adhered weakly to vitronectin compared with WT pMac. To counteract these transcriptional defects, we investigated TGFß1, as a candidate upstream regulator. TGFß1 failed to rescue vitronectin adhesion of pMac, although it improved αVß3 expression. CONCLUSIONS: The R47H mutation is not sufficient to cause gross phenotypic defects of human pMac under standard culture conditions. However, overlapping transcriptional defects with TREM2 KO supports the hypothesised partial loss-of-function effects of the R47H mutation. Furthermore, transcriptomics can guide us to more subtle phenotypic defects in the R47H cells, such as reduced cell adhesion, and can be used to predict targets for therapeutic intervention.


Assuntos
Doença de Alzheimer , Células-Tronco Pluripotentes Induzidas , Doença de Alzheimer/genética , Encéfalo , Humanos , Macrófagos , Glicoproteínas de Membrana/genética , Microglia , Fenótipo , Receptores Imunológicos/genética
7.
Dis Model Mech ; 13(3)2020 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-32298235

RESUMO

Regulation of protein synthesis makes a major contribution to post-transcriptional control pathways. During disease, or under stress, cells initiate processes to reprogramme protein synthesis and thus orchestrate the appropriate cellular response. Recent data show that the elongation stage of protein synthesis is a key regulatory node for translational control in health and disease. There is a complex set of factors that individually affect the overall rate of elongation and, for the most part, these influence either transfer RNA (tRNA)- and eukaryotic elongation factor 1A (eEF1A)-dependent codon decoding, and/or elongation factor 2 (eEF2)-dependent ribosome translocation along the mRNA. Decoding speeds depend on the relative abundance of each tRNA, the cognate:near-cognate tRNA ratios and the degree of tRNA modification, whereas eEF2-dependent ribosome translocation is negatively regulated by phosphorylation on threonine-56 by eEF2 kinase. Additional factors that contribute to the control of the elongation rate include epigenetic modification of the mRNA, coding sequence variation and the expression of eIF5A, which stimulates peptide bond formation between proline residues. Importantly, dysregulation of elongation control is central to disease mechanisms in both tumorigenesis and neurodegeneration, making the individual key steps in this process attractive therapeutic targets. Here, we discuss the relative contribution of individual components of the translational apparatus (e.g. tRNAs, elongation factors and their modifiers) to the overall control of translation elongation and how their dysregulation contributes towards disease processes.


Assuntos
Doença , Saúde , Elongação Traducional da Cadeia Peptídica , Aminoacilação , Animais , Carcinogênese/genética , Humanos , RNA de Transferência/genética , RNA de Transferência/metabolismo
8.
Biotechnol J ; 14(10): e1900024, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31119893

RESUMO

For a therapeutic monoclonal antibody (mAb) to reach the clinic, the molecule must be produced at an appropriate yield and quality, then formulated to maintain efficacy and stability. The formation of subvisible particles (SVPs) can impact product stability and is monitored during formulation development; however, the potential of a mAb to form such species can be influenced throughout the whole bioprocess. The levels of intracellular endoplasmic reticulum (ER) stress perceived by Chinese hamster ovary (CHO) cell lines, the day of mAb harvest, and the relationship with subsequent product stability of two mAbs (denoted A and B), as determined by the SVP content after accelerated stability studies, are reported here. Here, it is shown that the propensity of mAb A to form SVPs can be predicted by transcript expression of biomarkers of cellular ER stress, heavy/light-chain transcript and polypeptide amounts, and harvest day. Further, mAb A material harvested on day 9 of culture was more stable, in terms of SVP formation, than material harvested on day 13. These data suggest that ER stress perceived by CHO cells can reflect the stability of a mAb, and that biomarkers of such stress could help define culture harvest time as a tool to control SVP formation in formulated mAbs.


Assuntos
Anticorpos Monoclonais/isolamento & purificação , Biomarcadores/metabolismo , Retículo Endoplasmático/metabolismo , Animais , Anticorpos Monoclonais/química , Técnicas de Cultura Celular por Lotes , Células CHO , Cricetulus , Estresse do Retículo Endoplasmático
9.
Int J Obes (Lond) ; 43(8): 1653, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30940916

RESUMO

This paper was originally published under a standard licence. This has now been amended to a CC BY licence in the PDF and HTML.

10.
JAMA Pediatr ; 173(4): 385-386, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30776064

RESUMO

Clinical Question: How effective are diet, physical activity, and behavioral interventions in treating children aged 6 to 11 years with overweight or obesity? Bottom Line: Multicomponent behavior-changing interventions may be beneficial in achieving small, short-term reductions in body mass index (calculated as weight in kilograms divided by height in meters squared), body mass index z score, and weight in children aged 6 to 11 years. Adverse events, health-related quality of life, behavior change outcomes, and sociodemographics were poorly or inconsistently reported. Overall, the quality of the evidence was low or very low, with no evidence from lower-income countries.


Assuntos
Terapia Comportamental , Dieta , Exercício Físico , Obesidade Infantil/terapia , Criança , Feminino , Humanos , Masculino
11.
Int J Obes (Lond) ; 42(11): 1823-1833, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30301964

RESUMO

Children and adolescents with overweight and obesity are a global health concern. This is an integrative overview of six Cochrane systematic reviews, providing an up-to-date synthesis of the evidence examining interventions for the treatment of children and adolescents with overweight or obesity. The data extraction and quality assessments for each review were conducted by one author and checked by a second. The six high quality reviews provide evidence on the effectiveness of behaviour changing interventions conducted in children <6 years (7 trials), 6-11 years (70 trials), adolescents 12-17 years (44 trials) and interventions that target only parents of children aged 5-11 years (20 trials); in addition to interventions examining surgery (1 trial) and drugs (21 trials). Most of the evidence was derived from high-income countries and published in the last two decades. Collectively, the evidence suggests that multi-component behaviour changing interventions may be beneficial in achieving small reductions in body weight status in children of all ages, with low adverse event occurrence were reported. More research is required to understand which specific intervention components are most effective and in whom, and how best to maintain intervention effects. Evidence from surgical and drug interventions was too limited to make inferences about use and safety, and adverse events were a serious consideration.


Assuntos
Cirurgia Bariátrica , Terapia Comportamental , Dieta , Exercício Físico , Obesidade Infantil/terapia , Adolescente , Índice de Massa Corporal , Criança , Humanos , Obesidade Infantil/prevenção & controle , Revisões Sistemáticas como Assunto
12.
Cochrane Database Syst Rev ; 6: CD012691, 2017 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-28639320

RESUMO

BACKGROUND: Adolescent overweight and obesity has increased globally, and can be associated with short- and long-term health consequences. Modifying known dietary and behavioural risk factors through behaviour changing interventions (BCI) may help to reduce childhood overweight and obesity. This is an update of a review published in 2009. OBJECTIVES: To assess the effects of diet, physical activity and behavioural interventions for the treatment of overweight or obese adolescents aged 12 to 17 years. SEARCH METHODS: We performed a systematic literature search in: CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, LILACS, and the trial registers ClinicalTrials.gov and ICTRP Search Portal. We checked references of identified studies and systematic reviews. There were no language restrictions. The date of the last search was July 2016 for all databases. SELECTION CRITERIA: We selected randomised controlled trials (RCTs) of diet, physical activity and behavioural interventions for treating overweight or obesity in adolescents aged 12 to 17 years. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed risk of bias, evaluated the overall quality of the evidence using the GRADE instrument and extracted data following the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions. We contacted trial authors for additional information. MAIN RESULTS: We included 44 completed RCTs (4781 participants) and 50 ongoing studies. The number of participants in each trial varied (10 to 521) as did the length of follow-up (6 to 24 months). Participants ages ranged from 12 to 17.5 years in all trials that reported mean age at baseline. Most of the trials used a multidisciplinary intervention with a combination of diet, physical activity and behavioural components. The content and duration of the intervention, its delivery and the comparators varied across trials. The studies contributing most information to outcomes of weight and body mass index (BMI) were from studies at a low risk of bias, but studies with a high risk of bias provided data on adverse events and quality of life.The mean difference (MD) of the change in BMI at the longest follow-up period in favour of BCI was -1.18 kg/m2 (95% confidence interval (CI) -1.67 to -0.69); 2774 participants; 28 trials; low quality evidence. BCI lowered the change in BMI z score by -0.13 units (95% CI -0.21 to -0.05); 2399 participants; 20 trials; low quality evidence. BCI lowered body weight by -3.67 kg (95% CI -5.21 to -2.13); 1993 participants; 20 trials; moderate quality evidence. The effect on weight measures persisted in trials with 18 to 24 months' follow-up for both BMI (MD -1.49 kg/m2 (95% CI -2.56 to -0.41); 760 participants; 6 trials and BMI z score MD -0.34 (95% CI -0.66 to -0.02); 602 participants; 5 trials).There were subgroup differences showing larger effects for both BMI and BMI z score in studies comparing interventions with no intervention/wait list control or usual care, compared with those testing concomitant interventions delivered to both the intervention and control group. There were no subgroup differences between interventions with and without parental involvement or by intervention type or setting (health care, community, school) or mode of delivery (individual versus group).The rate of adverse events in intervention and control groups was unclear with only five trials reporting harms, and of these, details were provided in only one (low quality evidence). None of the included studies reported on all-cause mortality, morbidity or socioeconomic effects.BCIs at the longest follow-up moderately improved adolescent's health-related quality of life (standardised mean difference 0.44 ((95% CI 0.09 to 0.79); P = 0.01; 972 participants; 7 trials; 8 comparisons; low quality of evidence) but not self-esteem.Trials were inconsistent in how they measured dietary intake, dietary behaviours, physical activity and behaviour. AUTHORS' CONCLUSIONS: We found low quality evidence that multidisciplinary interventions involving a combination of diet, physical activity and behavioural components reduce measures of BMI and moderate quality evidence that they reduce weight in overweight or obese adolescents, mainly when compared with no treatment or waiting list controls. Inconsistent results, risk of bias or indirectness of outcome measures used mean that the evidence should be interpreted with caution. We have identified a large number of ongoing trials (50) which we will include in future updates of this review.


Assuntos
Terapia Comportamental , Índice de Massa Corporal , Exercício Físico , Comportamento Alimentar , Sobrepeso/terapia , Obesidade Infantil/terapia , Adolescente , Terapia Combinada , Humanos , Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como Assunto
13.
Cochrane Database Syst Rev ; 6: CD012651, 2017 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-28639319

RESUMO

BACKGROUND: Child and adolescent overweight and obesity has increased globally, and can be associated with significant short- and long-term health consequences. This is an update of a Cochrane review published first in 2003, and updated previously in 2009. However, the update has now been split into six reviews addressing different childhood obesity treatments at different ages. OBJECTIVES: To assess the effects of diet, physical activity and behavioural interventions (behaviour-changing interventions) for the treatment of overweight or obese children aged 6 to 11 years. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, LILACS as well as trial registers ClinicalTrials.gov and ICTRP Search Portal. We checked references of studies and systematic reviews. We did not apply any language restrictions. The date of the last search was July 2016 for all databases. SELECTION CRITERIA: We selected randomised controlled trials (RCTs) of diet, physical activity, and behavioural interventions (behaviour-changing interventions) for treating overweight or obese children aged 6 to 11 years, with a minimum of six months' follow-up. We excluded interventions that specifically dealt with the treatment of eating disorders or type 2 diabetes, or included participants with a secondary or syndromic cause of obesity. DATA COLLECTION AND ANALYSIS: Two review authors independently screened references, extracted data, assessed risk of bias, and evaluated the quality of the evidence using the GRADE instrument. We contacted study authors for additional information. We carried out meta-analyses according to the statistical guidelines in the Cochrane Handbook for Systematic Reviews of Interventions. MAIN RESULTS: We included 70 RCTs with a total of 8461 participants randomised to either the intervention or control groups. The number of participants per trial ranged from 16 to 686. Fifty-five trials compared a behaviour-changing intervention with no treatment/usual care control and 15 evaluated the effectiveness of adding an additional component to a behaviour-changing intervention. Sixty-four trials were parallel RCTs, and four were cluster RCTs. Sixty-four trials were multicomponent, two were diet only and four were physical activity only interventions. Ten trials had more than two arms. The overall quality of the evidence was low or very low and 62 trials had a high risk of bias for at least one criterion. Total duration of trials ranged from six months to three years. The median age of participants was 10 years old and the median BMI z score was 2.2.Primary analyses demonstrated that behaviour-changing interventions compared to no treatment/usual care control at longest follow-up reduced BMI, BMI z score and weight. Mean difference (MD) in BMI was -0.53 kg/m2 (95% confidence interval (CI) -0.82 to -0.24); P < 0.00001; 24 trials; 2785 participants; low-quality evidence. MD in BMI z score was -0.06 units (95% CI -0.10 to -0.02); P = 0.001; 37 trials; 4019 participants; low-quality evidence and MD in weight was -1.45 kg (95% CI -1.88 to -1.02); P < 0.00001; 17 trials; 1774 participants; low-quality evidence.Thirty-one trials reported on serious adverse events, with 29 trials reporting zero occurrences RR 0.57 (95% CI 0.17 to 1.93); P = 0.37; 4/2105 participants in the behaviour-changing intervention groups compared with 7/1991 participants in the comparator groups). Few trials reported health-related quality of life or behaviour change outcomes, and none of the analyses demonstrated a substantial difference in these outcomes between intervention and control. In two trials reporting on minutes per day of TV viewing, a small reduction of 6.6 minutes per day (95% CI -12.88 to -0.31), P = 0.04; 2 trials; 55 participants) was found in favour of the intervention. No trials reported on all-cause mortality, morbidity or socioeconomic effects, and few trials reported on participant views; none of which could be meta-analysed.As the meta-analyses revealed substantial heterogeneity, we conducted subgroup analyses to examine the impact of type of comparator, type of intervention, risk of attrition bias, setting, duration of post-intervention follow-up period, parental involvement and baseline BMI z score. No subgroup effects were shown for any of the subgroups on any of the outcomes. Some data indicated that a reduction in BMI immediately post-intervention was no longer evident at follow-up at less than six months, which has to be investigated in further trials. AUTHORS' CONCLUSIONS: Multi-component behaviour-changing interventions that incorporate diet, physical activity and behaviour change may be beneficial in achieving small, short-term reductions in BMI, BMI z score and weight in children aged 6 to 11 years. The evidence suggests a very low occurrence of adverse events. The quality of the evidence was low or very low. The heterogeneity observed across all outcomes was not explained by subgrouping. Further research is required of behaviour-changing interventions in lower income countries and in children from different ethnic groups; also on the impact of behaviour-changing interventions on health-related quality of life and comorbidities. The sustainability of reduction in BMI/BMI z score and weight is a key consideration and there is a need for longer-term follow-up and further research on the most appropriate forms of post-intervention maintenance in order to ensure intervention benefits are sustained over the longer term.


Assuntos
Terapia Comportamental , Índice de Massa Corporal , Exercício Físico , Sobrepeso/terapia , Obesidade Infantil/terapia , Criança , Terapia Combinada , Humanos , Sobrepeso/dietoterapia , Obesidade Infantil/dietoterapia , Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como Assunto
14.
Biotechnol J ; 12(8)2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28504349

RESUMO

mRNA translation is a key process determining growth, proliferation and duration of a Chinese hamster ovary (CHO) cell culture and influences recombinant protein synthesis rate. During bioprocessing, CHO cells can experience stresses leading to reprogramming of translation and decreased global protein synthesis. Here we apply polysome profiling to determine reprogramming and translational capabilities in host and recombinant monoclonal antibody-producing (mAb) CHO cell lines during batch culture. Recombinant cell lines with the fastest cell specific growth rates were those with the highest global translational efficiency. However, total ribosomal capacity, determined from polysome profiles, did not relate to the fastest growing or highest producing mAb cell line, suggesting it is the ability to utilise available machinery that determines protein synthetic capacity. Cell lines with higher cell specific productivities tended to have elevated recombinant heavy chain transcript copy numbers, localised to the translationally active heavy polysomes. The highest titre cell line was that which sustained recombinant protein synthesis and maintained high recombinant transcript copy numbers in polysomes. Investigation of specific endogenous transcripts revealed a number that maintained or reprogrammed into heavy polysomes, identifying targets for potential cell engineering or those with 5' untranslated regions that might be utilised to enhance recombinant transcript translation.


Assuntos
Anticorpos Monoclonais/genética , Polirribossomos/genética , Biossíntese de Proteínas , Proteínas Recombinantes/biossíntese , Animais , Anticorpos Monoclonais/biossíntese , Técnicas de Cultura Celular por Lotes , Células CHO , Engenharia Celular/métodos , Proliferação de Células/genética , Cricetulus , Polirribossomos/química , RNA Mensageiro/genética , Proteínas Recombinantes/genética , Ribossomos
15.
Cochrane Database Syst Rev ; 11: CD012436, 2016 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-27899001

RESUMO

BACKGROUND: Child and adolescent obesity has increased globally, and can be associated with significant short- and long-term health consequences. OBJECTIVES: To assess the efficacy of drug interventions for the treatment of obesity in children and adolescents. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, PubMed (subsets not available on Ovid), LILACS as well as the trial registers ICTRP (WHO) and ClinicalTrials.gov. Searches were undertaken from inception to March 2016. We checked references and applied no language restrictions. SELECTION CRITERIA: We selected randomised controlled trials (RCTs) of pharmacological interventions for treating obesity (licensed and unlicensed for this indication) in children and adolescents (mean age under 18 years) with or without support of family members, with a minimum of three months' pharmacological intervention and six months' follow-up from baseline. We excluded interventions that specifically dealt with the treatment of eating disorders or type 2 diabetes, or included participants with a secondary or syndromic cause of obesity. In addition, we excluded trials which included growth hormone therapies and pregnant participants. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed trial quality and extracted data following standard Cochrane methodology. Where necessary we contacted authors for additional information. MAIN RESULTS: We included 21 trials and identified eight ongoing trials. The included trials evaluated metformin (11 trials), sibutramine (six trials), orlistat (four trials), and one trial arm investigated the combination of metformin and fluoxetine. The ongoing trials evaluated metformin (four trials), topiramate (two trials) and exenatide (two trials). A total of 2484 people participated in the included trials, 1478 participants were randomised to drug intervention and 904 to comparator groups (91 participants took part in two cross-over trials; 11 participants not specified). Eighteen trials used a placebo in the comparator group. Two trials had a cross-over design while the remaining 19 trials were parallel RCTs. The length of the intervention period ranged from 12 weeks to 48 weeks, and the length of follow-up from baseline ranged from six months to 100 weeks.Trials generally had a low risk of bias for random sequence generation, allocation concealment and blinding (participants, personnel and assessors) for subjective and objective outcomes. We judged approximately half of the trials as having a high risk of bias in one or more domain such as selective reporting.The primary outcomes of this review were change in body mass index (BMI), change in weight and adverse events. All 21 trials measured these outcomes. The secondary outcomes were health-related quality of life (only one trial reported results showing no marked differences; very low certainty evidence), body fat distribution (measured in 18 trials), behaviour change (measured in six trials), participants' views of the intervention (not reported), morbidity associated with the intervention (measured in one orlistat trial only reporting more new gallstones following the intervention; very low certainty evidence), all-cause mortality (one suicide in the orlistat intervention group; low certainty evidence) and socioeconomic effects (not reported).Intervention versus comparator for mean difference (MD) in BMI change was -1.3 kg/m2 (95% confidence interval (CI) -1.9 to -0.8; P < 0.00001; 16 trials; 1884 participants; low certainty evidence). When split by drug type, sibutramine, metformin and orlistat all showed reductions in BMI in favour of the intervention.Intervention versus comparator for change in weight showed a MD of -3.9 kg (95% CI -5.9 to -1.9; P < 0.00001; 11 trials; 1180 participants; low certainty evidence). As with BMI, when the trials were split by drug type, sibutramine, metformin and orlistat all showed reductions in weight in favour of the intervention.Five trials reported serious adverse events: 24/878 (2.7%) participants in the intervention groups versus 8/469 (1.7%) participants in the comparator groups (risk ratio (RR) 1.43, 95% CI 0.63 to 3.25; 1347 participants; low certainty evidence). A total 52/1043 (5.0%) participants in the intervention groups versus 17/621 (2.7%) in the comparator groups discontinued the trial because of adverse events (RR 1.45, 95% CI 0.83 to 2.52; 10 trials; 1664 participants; low certainty evidence). The most common adverse events in orlistat and metformin trials were gastrointestinal (such as diarrhoea, mild abdominal pain or discomfort, fatty stools). The most frequent adverse events in sibutramine trials included tachycardia, constipation and hypertension. The single fluoxetine trial reported dry mouth and loose stools. No trial investigated drug treatment for overweight children. AUTHORS' CONCLUSIONS: This systematic review is part of a series of associated Cochrane reviews on interventions for obese children and adolescents and has shown that pharmacological interventions (metformin, sibutramine, orlistat and fluoxetine) may have small effects in reduction in BMI and bodyweight in obese children and adolescents. However, many of these drugs are not licensed for the treatment of obesity in children and adolescents, or have been withdrawn. Trials were generally of low quality with many having a short or no post-intervention follow-up period and high dropout rates (overall dropout of 25%). Future research should focus on conducting trials with sufficient power and long-term follow-up, to ensure the long-term effects of any pharmacological intervention are comprehensively assessed. Adverse events should be reported in a more standardised manner specifying amongst other things the number of participants experiencing at least one adverse event. The requirement of regulatory authorities (US Food and Drug Administration and European Medicines Agency) for trials of all new medications to be used in children and adolescents should drive an increase in the number of high quality trials.


Assuntos
Fármacos Antiobesidade/uso terapêutico , Obesidade Infantil/tratamento farmacológico , Adolescente , Fármacos Antiobesidade/efeitos adversos , Índice de Massa Corporal , Criança , Ciclobutanos/uso terapêutico , Fluoxetina/uso terapêutico , Humanos , Lactonas/uso terapêutico , Metformina/uso terapêutico , Orlistate , Ensaios Clínicos Controlados Aleatórios como Assunto
16.
J Alzheimers Dis ; 54(4): 1521-1538, 2016 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-27589517

RESUMO

Intracellular neurofibrillary tangles (NFTs) are the hallmark of Alzheimer's disease and other tauopathies in which tau, a microtubule-associated protein, loses its ability to stabilize microtubules. Several post-translational modifications including phosphorylation and truncation increase tau's propensity to aggregate thus forming NFTs; however, the mechanisms underlying tau conformational change and aggregation still remain to be defined. Caspase activation and subsequent proteolytic cleavage of tau is thought to be a potential trigger of this disease-related pathological conformation. The aim of this work was to investigate the link between caspase activation and a disease-related conformational change of tau in a neuroblastoma cell-based model of spontaneous tau aggregation. We demonstrated that caspase induction initiates proteolytic cleavage of tau and generation of conformationally altered and aggregated tau recognized by the MC1 conformational antibody. Most importantly, these events were shown to be attenuated with caspase inhibitors. This implies that therapeutics aimed at inhibiting caspase-mediated tau cleavage may prove beneficial in slowing cleavage and aggregation, thus potentially halting tau pathology and disease progression.


Assuntos
Inibidores de Caspase/farmacologia , Caspases/metabolismo , ATPases Transportadoras de Cobre/metabolismo , Agregação Patológica de Proteínas/metabolismo , Proteínas tau/metabolismo , Animais , Linhagem Celular Tumoral , ATPases Transportadoras de Cobre/química , Relação Dose-Resposta a Droga , Ativação Enzimática/efeitos dos fármacos , Ativação Enzimática/fisiologia , Inibidores Enzimáticos/farmacologia , Humanos , Camundongos , Agregação Patológica de Proteínas/patologia , Conformação Proteica/efeitos dos fármacos , Estaurosporina/farmacologia , Proteínas tau/química
17.
Cochrane Database Syst Rev ; 3: CD012105, 2016 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-26961576

RESUMO

BACKGROUND: Child overweight and obesity has increased globally, and can be associated with short- and long-term health consequences. OBJECTIVES: To assess the effects of diet, physical activity, and behavioural interventions for the treatment of overweight or obesity in preschool children up to the age of 6 years. SEARCH METHODS: We performed a systematic literature search in the databases Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL, and LILACS, as well as in the trial registers ClinicalTrials.gov and ICTRP Search Portal. We also checked references of identified trials and systematic reviews. We applied no language restrictions. The date of the last search was March 2015 for all databases. SELECTION CRITERIA: We selected randomised controlled trials (RCTs) of diet, physical activity, and behavioural interventions for treating overweight or obesity in preschool children aged 0 to 6 years. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed risk of bias, evaluated the overall quality of the evidence using the GRADE instrument, and extracted data following the Cochrane Handbook for Systematic Reviews of Interventions. We contacted trial authors for additional information. MAIN RESULTS: We included 7 RCTs with a total of 923 participants: 529 randomised to an intervention and 394 to a comparator. The number of participants per trial ranged from 18 to 475. Six trials were parallel RCTs, and one was a cluster RCT. Two trials were three-arm trials, each comparing two interventions with a control group. The interventions and comparators in the trials varied. We categorised the comparisons into two groups: multicomponent interventions and dietary interventions. The overall quality of the evidence was low or very low, and six trials had a high risk of bias on individual 'Risk of bias' criteria. The children in the included trials were followed up for between six months and three years.In trials comparing a multicomponent intervention with usual care, enhanced usual care, or information control, we found a greater reduction in body mass index (BMI) z score in the intervention groups at the end of the intervention (6 to 12 months): mean difference (MD) -0.3 units (95% confidence interval (CI) -0.4 to -0.2); P < 0.00001; 210 participants; 4 trials; low-quality evidence, at 12 to 18 months' follow-up: MD -0.4 units (95% CI -0.6 to -0.2); P = 0.0001; 202 participants; 4 trials; low-quality evidence, and at 2 years' follow-up: MD -0.3 units (95% CI -0.4 to -0.1); 96 participants; 1 trial; low-quality evidence.One trial stated that no adverse events were reported; the other trials did not report on adverse events. Three trials reported health-related quality of life and found improvements in some, but not all, aspects. Other outcomes, such as behaviour change and parent-child relationship, were inconsistently measured.One three-arm trial of very low-quality evidence comparing two types of diet with control found that both the dairy-rich diet (BMI z score change MD -0.1 units (95% CI -0.11 to -0.09); P < 0.0001; 59 participants) and energy-restricted diet (BMI z score change MD -0.1 units (95% CI -0.11 to -0.09); P < 0.0001; 57 participants) resulted in greater reduction in BMI than the comparator at the end of the intervention period, but only the dairy-rich diet maintained this at 36 months' follow-up (BMI z score change in MD -0.7 units (95% CI -0.71 to -0.69); P < 0.0001; 52 participants). The energy-restricted diet had a worse BMI outcome than control at this follow-up (BMI z score change MD 0.1 units (95% CI 0.09 to 0.11); P < 0.0001; 47 participants). There was no substantial difference in mean daily energy expenditure between groups. Health-related quality of life, adverse effects, participant views, and parenting were not measured.No trial reported on all-cause mortality, morbidity, or socioeconomic effects.All results should be interpreted cautiously due to their low quality and heterogeneous interventions and comparators. AUTHORS' CONCLUSIONS: Muticomponent interventions appear to be an effective treatment option for overweight or obese preschool children up to the age of 6 years. However, the current evidence is limited, and most trials had a high risk of bias. Most trials did not measure adverse events. We have identified four ongoing trials that we will include in future updates of this review.The role of dietary interventions is more equivocal, with one trial suggesting that dairy interventions may be effective in the longer term, but not energy-restricted diets. This trial also had a high risk of bias.


Assuntos
Índice de Massa Corporal , Obesidade/terapia , Sobrepeso/terapia , Terapia Comportamental , Peso Corporal , Criança , Pré-Escolar , Dieta , Nível de Saúde , Humanos , Atividade Motora , Obesidade/psicologia , Sobrepeso/psicologia , Relações Pais-Filho , Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como Assunto , Autoimagem
18.
Cochrane Database Syst Rev ; (12): CD012008, 2015 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-26690844

RESUMO

BACKGROUND: Child and adolescent overweight and obesity have increased globally, and are associated with short- and long-term health consequences. OBJECTIVES: To assess the efficacy of diet, physical activity and behavioural interventions delivered to parents only for the treatment of overweight and obesity in children aged 5 to 11 years. SEARCH METHODS: We performed a systematic literature search of databases including the Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL and LILACS as well trial registers. We checked references of identified trials and systematic reviews. We applied no language restrictions. The date of the last search was March 2015 for all databases. SELECTION CRITERIA: We selected randomised controlled trials (RCTs) of diet, physical activity and behavioural interventions delivered to parents only for treating overweight or obesity in children aged 5 to 11 years. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed trials for risk of bias and evaluated overall study quality using the GRADE instrument. Where necessary, we contacted authors for additional information. MAIN RESULTS: We included 20 RCTs, including 3057 participants. The number of participants ranged per trial between 15 and 645. Follow-up ranged between 24 weeks and two years. Eighteen trials were parallel RCTs and two were cluster RCTs. Twelve RCTs had two comparisons and eight RCTs had three comparisons. The interventions varied widely; the duration, content, delivery and follow-up of the interventions were heterogeneous. The comparators also differed. This review categorised the comparisons into four groups: parent-only versus parent-child, parent-only versus waiting list controls, parent-only versus minimal contact interventions and parent-only versus other parent-only interventions.Trial quality was generally low with a large proportion of trials rated as high risk of bias on individual risk of bias criteria.In trials comparing a parent-only intervention with a parent-child intervention, the body mass index (BMI) z score change showed a mean difference (MD) at the longest follow-up period (10 to 24 months) of -0.04 (95% confidence interval (CI) -0.15 to 0.08); P = 0.56; 267 participants; 3 trials; low quality evidence. In trials comparing a parent-only intervention with a waiting list control, the BMI z score change in favour of the parent-only intervention at the longest follow-up period (10-12 months) had an MD of -0.10 (95% CI -0.19 to -0.01); P = 0.04; 136 participants; 2 trials; low quality evidence. BMI z score change of parent-only interventions when compared with minimal contact control interventions at the longest follow-up period (9 to 12 months) showed an MD of 0.01 (95% CI -0.07 to 0.09); P = 0.81; 165 participants; 1 trial; low quality evidence. There were few similarities between interventions and comparators across the included trials in the parent-only intervention versus other parent-only interventions and we did not pool these data. Generally, these trials did not show substantial differences between their respective parent-only groups on BMI outcomes.Other outcomes such as behavioural measures, parent-child relationships and health-related quality of life were reported inconsistently. Adverse effects of the interventions were generally not reported, two trials stated that there were no serious adverse effects. No trials reported on all-cause mortality, morbidity or socioeconomic effects.All results need to be interpreted cautiously because of their low quality, the heterogeneous interventions and comparators, and the high rates of non-completion. AUTHORS' CONCLUSIONS: Parent-only interventions may be an effective treatment option for overweight or obese children aged 5 to 11 years when compared with waiting list controls. Parent-only interventions had similar effects compared with parent-child interventions and compared with those with minimal contact controls. However, the evidence is at present limited; some of the trials had a high risk of bias with loss to follow-up being a particular issue and there was a lack of evidence for several important outcomes. The systematic review has identified 10 ongoing trials that have a parent-only arm, which will contribute to future updates. These trials will improve the robustness of the analyses by type of comparator, and may permit subgroup analysis by intervention component and the setting. Trial reports should provide adequate details about the interventions to be replicated by others. There is a need to conduct and report cost-effectiveness analyses in future trials in order to establish whether parent-only interventions are more cost-effective than parent-child interventions.


Assuntos
Pais/educação , Obesidade Infantil/terapia , Índice de Massa Corporal , Peso Corporal , Criança , Pré-Escolar , Nível de Saúde , Humanos , Sobrepeso/terapia , Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como Assunto , Autoimagem
19.
Biochem J ; 472(3): 261-73, 2015 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-26420881

RESUMO

Translation initiation is on the critical pathway for the production of monoclonal antibodies (mAbs) by mammalian cells. Formation of a closed loop structure comprised of mRNA, a number of eukaryotic initiation factors (eIFs) and ribosomal proteins has been proposed to aid re-initiation of translation and therefore increase global translational efficiency. We have determined mRNA and protein levels of the key components of the closed loop, eIFs (eIF3a, eIF3b, eIF3c, eIF3h, eIF3i and eIF4G1), poly(A)-binding protein (PABP) 1 and PABP-interacting protein 1 (PAIP1), across a panel of 30 recombinant mAb-producing GS-CHOK1SV cell lines with a broad range of growth characteristics and production levels of a model recombinant mAb. We have used a multi-level statistical approach to investigate the relationship between key performance indicators (cell growth and recombinant antibody productivity) and the intracellular amounts of target translation initiation factor proteins and the mRNAs encoding them. We show that high-producing cell lines maintain amounts of the translation initiation factors involved in the formation of the closed loop mRNA, maintaining these proteins at appropriate levels to deliver enhanced recombinant protein production. We then utilize knowledge of the amounts of these factors to build predictive models for and use cluster analysis to identify, high-producing cell lines. The present study therefore defines the translation initiation factor amounts that are associated with highly productive recombinant GS-CHOK1SV cell lines that may be targets for screening highly productive cell lines or to engineer new host cell lines with the potential for enhanced recombinant antibody productivity.


Assuntos
Anticorpos Monoclonais/biossíntese , Engenharia Celular/métodos , Fatores de Iniciação em Eucariotos/biossíntese , Expressão Gênica , Animais , Anticorpos Monoclonais/genética , Células CHO , Cricetinae , Cricetulus , Fatores de Iniciação em Eucariotos/genética , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/genética
20.
Cochrane Database Syst Rev ; (6): CD011740, 2015 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-26104326

RESUMO

BACKGROUND: Child and adolescent overweight and obesity have increased globally, and are associated with significant short and long term health consequences. OBJECTIVES: To assess the effects of surgical interventions for treating obesity in childhood and adolescence. SEARCH METHODS: We searched the Cochrane Library, MEDLINE, PubMed, EMBASE as well as LILACS, ICTRP Search Portal and ClinicalTrials.gov (all from database inception to March 2015). References of identified studies and systematic reviews were checked. No language restrictions were applied. SELECTION CRITERIA: We selected randomised controlled trials (RCTs) of surgical interventions for treating obesity in children and adolescents (age < 18 years) with a minimum of six months follow-up. Interventions that specifically dealt with the treatment of eating disorders or type 2 diabetes, or included participants with a secondary or syndromic cause of obesity were excluded. Pregnant females were also excluded. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed risk of bias and extracted data. Where necessary authors were contacted for additional information. MAIN RESULTS: We included one RCT (a total of 50 participants, 25 in both the intervention and comparator group). The intervention focused on laparoscopic adjustable gastric banding surgery, which was compared to a control group receiving a multi component lifestyle programme. The participating population consisted of Australian adolescents (a higher proportion of girls than boys) aged 14 to 18 years, with a mean age of 16.5 and 16.6 years in the gastric banding and lifestyle group, respectively which was conducted in a private hospital, receiving funding from the gastric banding manufacturer. The study authors were unable to blind participants, personnel and outcome assessors which may have resulted in a high risk of performance and detection bias. Attrition bias was noted as well. The study authors reported a mean reduction in weight of 34.6 kg (95% confidence interval (CI) 30.2 to 39.0) at two years, representing a change in body mass index (BMI) of 12.7 (95% CI 11.3 to 14.2) for the surgery intervention; and a mean reduction in weight of 3.0 kg (95% CI 2.1 to 8.1) representing a change in BMI of 1.3 (95% CI 0.4 to 2.9) for the lifestyle intervention. The differences between groups were statistically significant for all weight measures at 24 months (P < 0.001). The overall quality of the evidence according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) was low. Adverse events were reported in 12/25 (48%) participants in the intervention group compared to 11/25 (44%) in the control group (low quality evidence). A total of 28% of the adolescents undergoing gastric banding required revisional surgery. No data were reported for all-cause mortality, behaviour change, participants views of the intervention and socioeconomic effects. At two years, the gastric banding group performed better than the lifestyle group in two of eight health-related quality of life concepts (very low quality evidence) as measured by the Child Health Questionnaire (physical functioning score (94 versus 78, community norm 95) and change in health score (4.4 versus 3.6, community norm 3.5)). AUTHORS' CONCLUSIONS: Laparoscopic gastric banding led to greater body weight loss compared to a multi component lifestyle program in one small study with 50 patients. These results do not provide enough data to assess efficacy across populations from different countries, socioeconomic and ethnic backgrounds, who may respond differently. This systematic review highlights the lack of RCTs in this field. Future studies should assess the impact of the surgical procedure and post operative care to minimise adverse events, including the need for post operative adjustments and revisional surgery. Long-term follow-up is also critical to comprehensively assess the impact of surgery as participants enter adulthood.


Assuntos
Gastroplastia/métodos , Obesidade Infantil/cirurgia , Adolescente , Austrália , Criança , Feminino , Humanos , Estilo de Vida , Masculino , Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como Assunto , Redução de Peso
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