41 research outputs found

    The thanatophoric dysplasia type II mutation hampers complete maturation of fibroblast growth factor receptor 3 (FGFR3), which activates signal transducer and activator of transcription 1 (STAT1) from the endoplasmic reticulum

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    The K650E substitution in the fibroblast growth factor receptor 3 (FGFR3) causes constitutive tyrosine kinase activity of the receptor and is associated to the lethal skeletal disorder, thanatophoric dysplasia type II (TDII). The underlying mechanisms of how the activated FGFR3 causes TDII remains to be elucidated. FGFR3 is a transmembrane glycoprotein, which is synthesized through three isoforms, with various degrees of N-glycosylation. We have studied whether immature FGFR3 isoforms mediate the abnormal signaling in TDII. We show that synthesis of TDII-FGFR3 presents two phosphorylated forms: the immature non-glycosylated 98-kDa peptides and the intermediate 120-kDa glycomers. The mature, fully glycosylated 130-kDa forms, detected in wild type FGFR3, are not present in TDII. Endoglycosidase H cleaves the sugars on TDII intermediates thus indicating their intracellular localization in the endoplasmic reticulum. Accordingly, TDII-FGFR3-GFP co-localizes with calreticulin in the endoplasmic reticulum. Furthermore, following TDII transfection, signal transducer and activator of transcription 1 (STAT1) is phosphorylated in the absence of FGFR3 ligand and brefeldin A does not inhibit its activation. On the contrary, the cell membrane-anchored FRS2alpha protein is not activated in TDII cells. The opposite situation is observed in stable TDII cell clones where, despite the presence of phosphorylated mature receptor, STAT1 is not activated whereas FRS2alpha is phosphorylated. We speculate that the selection process favors cells defective in STAT1 activation through the 120-kDa TDII-FGFR3, thus allowing growth of the TDII cell clones. Accordingly, apoptosis is observed following TDII-FGFR3 transfection. These observations highlight the importance of the immature TDII-FGFR3 proteins as mediators of an abnormal signaling in TDII

    Heterogeneity of Signal Transducer and Activator of Transcription Binding Sites in the Long-Terminal Repeats of Distinct HIV-1 Subtypes

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    HIV-1 can be subdivided into distinct subtypes; the consequences of such a genomic variability remain largely speculative. The long terminal repeats (LTR) control HIV transcription and reflect the major differences of distinct viral subtypes. Three regions in the HIV-1 subtype B LTR are close matches to the Signal Transducer and Activator of Transcription (STAT) consensus sequence. Here, we show heterogeneity in these putative STAT binding sites among HIV-1 LTR subtypes A through G. Transfection of constitutively activated STAT5 lead to transcriptional activation of HIV-1 expression in 293T cells transfected with a reporter assay driven by HIV-1 LTR subtype B. Constitutively activated STAT5 transactivated the LTR of various subtypes in U937 cells with different potency. These findings support and expand the potential relevance of STAT5 activation in HIV infection and may bear relevance for a differential regulation of latency and expression of different subtypes of HIV-1

    Efficacy of RTS,S/AS01E vaccine against malaria in children 5 to 17 months of age.

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    BACKGROUND: Plasmodium falciparum malaria is a pressing global health problem. A previous study of the malaria vaccine RTS,S (which targets the circumsporozoite protein), given with an adjuvant system (AS02A), showed a 30% rate of protection against clinical malaria in children 1 to 4 years of age. We evaluated the efficacy of RTS,S given with a more immunogenic adjuvant system (AS01E) in children 5 to 17 months of age, a target population for vaccine licensure. METHODS: We conducted a double-blind, randomized trial of RTS,S/AS01E vaccine as compared with rabies vaccine in children in Kilifi, Kenya, and Korogwe, Tanzania. The primary end point was fever with a falciparum parasitemia density of more than 2500 parasites per microliter, and the mean duration of follow-up was 7.9 months (range, 4.5 to 10.5). RESULTS: A total of 894 children were randomly assigned to receive the RTS,S/AS01E vaccine or the control (rabies) vaccine. Among the 809 children who completed the study procedures according to the protocol, the cumulative number in whom clinical malaria developed was 32 of 402 assigned to receive RTS,S/AS01E and 66 of 407 assigned to receive the rabies vaccine; the adjusted efficacy rate for RTS,S/AS01E was 53% (95% confidence interval [CI], 28 to 69; P<0.001) on the basis of Cox regression. Overall, there were 38 episodes of clinical malaria among recipients of RTS,S/AS01E, as compared with 86 episodes among recipients of the rabies vaccine, with an adjusted rate of efficacy against all malarial episodes of 56% (95% CI, 31 to 72; P<0.001). All 894 children were included in the intention-to-treat analysis, which showed an unadjusted efficacy rate of 49% (95% CI, 26 to 65; P<0.001). There were fewer serious adverse events among recipients of RTS,S/AS01E, and this reduction was not only due to a difference in the number of admissions directly attributable to malaria. CONCLUSIONS: RTS,S/AS01E shows promise as a candidate malaria vaccine. (ClinicalTrials.gov number, NCT00380393.

    Safety of the Malaria Vaccine Candidate, RTS,S/AS01E in 5 to 17 Month Old Kenyan and Tanzanian Children

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    The malaria vaccine candidate, RTS,S/AS01E, showed promising protective efficacy in a trial of Kenyan and Tanzanian children aged 5 to 17 months. Here we report on the vaccine's safety and tolerability. The experimental design was a Phase 2b, two-centre, double-blind (observer- and participant-blind), randomised (1∶1 ratio) controlled trial. Three doses of study or control (rabies) vaccines were administered intramuscularly at 1 month intervals. Solicited adverse events (AEs) were collected for 7 days after each vaccination. There was surveillance and reporting for unsolicited adverse events for 30 days after each vaccination. Serious adverse events (SAEs) were recorded throughout the study period which lasted for 14 months after dose 1 in Korogwe, Tanzania and an average of 18 months post-dose 1 in Kilifi, Kenya. Blood samples for safety monitoring of haematological, renal and hepatic functions were taken at baseline, 3, 10 and 14 months after dose 1. A total of 894 children received RTS,S/AS01E or rabies vaccine between March and August 2007. Overall, children vaccinated with RTS,S/AS01E had fewer SAEs (51/447) than children in the control group (88/447). One SAE episode in a RTS,S/AS01E recipient and nine episodes among eight rabies vaccine recipients met the criteria for severe malaria. Unsolicited AEs were reported in 78% of subjects in the RTS,S/AS01E group and 74% of subjects in the rabies vaccine group. In both vaccine groups, gastroenteritis and pneumonia were the most frequently reported unsolicited AE. Fever was the most frequently observed solicited AE and was recorded after 11% of RTS,S/AS01E doses compared to 31% of doses of rabies vaccine. The candidate vaccine RTS,S/AS01E showed an acceptable safety profile in children living in a malaria-endemic area in East Africa. More data on the safety of RTS,S/AS01E will become available from the Phase 3 programme

    Immunogenicity of the RTS,S/AS01 malaria vaccine and implications for duration of vaccine efficacy:Secondary analysis of data from a phase 3 randomised controlled trial

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    BACKGROUND: The RTS,S/AS01 malaria vaccine targets the circumsporozoite protein, inducing antibodies associated with the prevention of Plasmodium falciparum infection. We assessed the association between anti-circumsporozoite antibody titres and the magnitude and duration of vaccine efficacy using data from a phase 3 trial done between 2009 and 2014. METHODS: Using data from 8922 African children aged 5-17 months and 6537 African infants aged 6-12 weeks at first vaccination, we analysed the determinants of immunogenicity after RTS,S/AS01 vaccination with or without a booster dose. We assessed the association between the incidence of clinical malaria and anti-circumsporozoite antibody titres using a model of anti-circumsporozoite antibody dynamics and the natural acquisition of protective immunity over time. FINDINGS: RTS,S/AS01-induced anti-circumsporozoite antibody titres were greater in children aged 5-17 months than in those aged 6-12 weeks. Pre-vaccination anti-circumsporozoite titres were associated with lower immunogenicity in children aged 6-12 weeks and higher immunogenicity in those aged 5-17 months. The immunogenicity of the booster dose was strongly associated with immunogenicity after primary vaccination. Anti-circumsporozoite titres wane according to a biphasic exponential distribution. In participants aged 5-17 months, the half-life of the short-lived component of the antibody response was 45 days (95% credible interval 42-48) and that of the long-lived component was 591 days (557-632). After primary vaccination 12% (11-13) of the response was estimated to be long-lived, rising to 30% (28-32%) after a booster dose. An anti-circumsporozoite antibody titre of 121 EU/mL (98-153) was estimated to prevent 50% of infections. Waning anti-circumsporozoite antibody titres predict the duration of efficacy against clinical malaria across different age categories and transmission intensities, and efficacy wanes more rapidly at higher transmission intensity. INTERPRETATION: Anti-circumsporozoite antibody titres are a surrogate of protection for the magnitude and duration of RTS,S/AS01 efficacy, with or without a booster dose, providing a valuable surrogate of effectiveness for new RTS,S formulations in the age groups considered. FUNDING: UK Medical Research Council

    REQUITE: A prospective multicentre cohort study of patients undergoing radiotherapy for breast, lung or prostate cancer

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    Purpose: REQUITE aimed to establish a resource for multi-national validation of models and biomarkers that predict risk of late toxicity following radiotherapy. The purpose of this article is to provide summary descriptive data. Methods: An international, prospective cohort study recruited cancer patients in 26 hospitals in eight countries between April 2014 and March 2017. Target recruitment was 5300 patients. Eligible patients had breast, prostate or lung cancer and planned potentially curable radiotherapy. Radiotherapy was prescribed according to local regimens, but centres used standardised data collection forms. Pre-treatment blood samples were collected. Patients were followed for a minimum of 12 (lung) or 24 (breast/prostate) months and summary descriptive statistics were generated. Results: The study recruited 2069 breast (99% of target), 1808 prostate (86%) and 561 lung (51%) cancer patients. The centralised, accessible database includes: physician-(47,025 forms) and patient-(54,901) reported outcomes; 11,563 breast photos; 17,107 DICOMs and 12,684 DVHs. Imputed genotype data are available for 4223 patients with European ancestry (1948 breast, 1728 prostate, 547 lung). Radiation-induced lymphocyte apoptosis (RILA) assay data are available for 1319 patients. DNA (n = 4409) and PAXgene tubes (n = 3039) are stored in the centralised biobank. Example prevalences of 2-year (1-year for lung) grade >= 2 CTCAE toxicities are 13% atrophy (breast), 3% rectal bleeding (prostate) and 27% dyspnoea (lung). Conclusion: The comprehensive centralised database and linked biobank is a valuable resource for the radiotherapy community for validating predictive models and biomarkers. Patient summary: Up to half of cancer patients undergo radiation therapy and irradiation of surrounding healthy tissue is unavoidable. Damage to healthy tissue can affect short-and long-term quality-of-life. Not all patients are equally sensitive to radiation "damage" but it is not possible at the moment to identify those who are. REQUITE was established with the aim of trying to understand more about how we could predict radiation sensitivity. The purpose of this paper is to provide an overview and summary of the data and material available. In the REQUITE study 4400 breast, prostate and lung cancer patients filled out questionnaires and donated blood. A large amount of data was collected in the same way. With all these data and samples a database and biobank were created that showed it is possible to collect this kind of information in a standardised way across countries. In the future, our database and linked biobank will be a resource for research and validation of clinical predictors and models of radiation sensitivity. REQUITE will also enable a better understanding of how many people suffer with radiotherapy toxicity

    The use of Click chemistry for quantitative analysis of protein palmitoylation

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    S-palmitoylation attracts more and more attention of neuroscientists, since it is the most common and the only reversible posttranslational lipidation of neuronal proteins. The reversibility of this modification allows it to regulate function of proteins in a dynamic way by controlling their membrane binding, lipid raft localization, trafficking, stability and interactions with other proteins. Selection of the adequate S-palmitoylation analysis method is particularly important for quantification of S-acylation turnover dynamics. The conventional technique is the metabolic labeling with radioactive 3H- or 125I- palmitate and subsequent detection by fluorography. Despite it is widespread, this approach is hazard and time-consuming. The last decade was marked by the real breakthrough in S-palmitoylation field due to the development of new methods, as acyl-biotin exchange (ABE) and metabolic labeling with a palmitic acid analog followed by click chemistry (MLCC). MLCC that is based on metabolic labeling with bioorthogonal palmitic acid analog, linked post-vivo to the specific tag by click chemistry, is an alternative to radiolabeling. Yet this method was used mainly for global qualitative profiling of S-palmitoylated proteins (palmitome), while quantitative palmitoylation analysis of single protein is usually assessed by radiolabeling. Here, we describe the optimization of methodology applicable for quantification of protein palmitoylation based on MLCC, focusing on palmitoylation of the neural cell adhesion molecule (NCAM) by its acyltransferase DHHC3 and the autopalmitoylation of DHHC3. Briefly, quantification is achieved by the enrichment of palmitoylated proteins, linked to biotin tag during MLCC, by streptavidin-sepharose beads, followed by detection of protein of interest (NCAM or DHHC3) using immunoblotting and normalization to total protein level recovered after MLCC. The procedure is relatively safe and fast, with a possibility to access dynamical changes. The key feature of the method is standardization of the palmitoylation assessment of the chosen protein. It increases the reproducibility of observed palmitoylation changes, minimizing the variations introduced by numerous steps of MLCC reaction and protein enrichment. The optimized protocol allows to detect palmitoylation of several proteins in parallel, one of which could serve as an additional internal control
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