Exploring Cooperation and Competition in Molecular Chaperone Networks with Chemical Genetics and Peptide Microarrays.

Molecular chaperones are conserved proteins that maintain proteostasis in all organisms. Chaperones bind to unfolded protein substrates and promote outcomes such as folding, localization, aggregation prevention, and degradation. One chaperone, 70-kDa heat shock protein (Hsp70), is ubiquitously expressed and acts as a coordinating hub for a large network of co-chaperones, including J proteins, nucleotide exchange factors (NEFs), and tetratricopeptide-repeat (TPR) domain-containing proteins. The complexity of this network has posed challenges to understanding its roles in cellular health and how these roles may fail in diseases of protein misfolding, such as Alzheimer’s disease (AD). We attempted to gain a more detailed understanding of these networks using techniques that allow us to probe the function of many chaperones in parallel. Using chemical genetics, we investigated the functional roles of individual J proteins in Saccharomyces cerevisiae. We also designed peptide microarrays derived from the sequences of two model chaperone substrates, luciferase and tau. We used the luciferase array to investigate the mechanistic basis of the divergent abilities of two homologous J proteins to refold luciferase. We also mapped the binding of 17 chaperones to tau, a protein that aggregates in a class of neurodegenerative diseases called tauopathies, including AD. We find that chaperones bind a set of “hotspots” on tau, many of which are rich in residues known to be phosphorylated in AD tau or sites of mutations linked to tauopathies. These results suggest that chaperones compete with one another and other tau binding partners to direct tau metabolism in both healthy and diseased systems. Finally, we designed a peptide microarray to test the hypothesis that chaperones might preferentially bind amyloidogenic sequences to prevent the formation of toxic amyloid fibrils. We found that some chaperones, including Hsp70 and some J proteins, have a slight but consistent preference to bind amyloid-forming peptides over non-aggregating ones. In subsequent solution-phase binding assays, we confirm this finding but also conclude that other peptide properties contribute strongly to Hsp70 binding. Taken together, these studies advance our understanding of chaperone networks and suggest novel future avenues of inquiry.PHDChemical BiologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/99901/1/gilliesa_1.pd

Relative importance of informational items in Participant Information Leaflets for trials : a Q-Methodology approach

Acknowledgements: The authors would like to thank the stakeholders who participated in the study for their time. Funding: This work was supported by personal fellowship award (to KG) from the Medical Research Council Strategic Skills Methodology Fellowship (MRC MR/ L01193X/1). KI and SC were supported by awards from the National Institute for Health Research Health Technology Assessment Programme (HTA ref 14/192/71, HTA ref 11/58/15). The Health Services Research Unit is supported by a core grant from the Chief Scientist Office of the Scottish Government Health and Social Care Directorates.Peer reviewedPublisher PD

Enclosures of the mind : intellectual monopolies; a resource kit on community knowledge, biodiversity and intellectual property

Project number related to IDRC support could not be determinedPrepared for the Community Biodiversity Development and Conservation Progra

Overcoming barriers to engaging socio-economically disadvantaged populations in CHD primary prevention: a qualitative study

<p><b>Background:</b> Preventative medicine has become increasingly important in efforts to reduce the burden of chronic disease in industrialised countries. However, interventions that fail to recruit socio-economically representative samples may widen existing health inequalities. This paper explores the barriers and facilitators to engaging a socio-economically disadvantaged (SED) population in primary prevention for coronary heart disease (CHD).</p> <p><b>Methods:</b> The primary prevention element of Have a Heart Paisley (HaHP) offered risk screening to all eligible individuals. The programme employed two approaches to engaging with the community: a) a social marketing campaign and b) a community development project adopting primarily face-to-face canvassing. Individuals living in areas of SED were under-recruited via the social marketing approach, but successfully recruited via face-to-face canvassing. This paper reports on focus group discussions with participants, exploring their perceptions about and experiences of both approaches.</p> <p><b>Results:</b> Various reasons were identified for low uptake of risk screening amongst individuals living in areas of high SED in response to the social marketing campaign and a number of ways in which the face-to-face canvassing approach overcame these barriers were identified. These have been categorised into four main themes: (1) processes of engagement; (2) issues of understanding; (3) design of the screening service and (4) the priority accorded to screening. The most immediate barriers to recruitment were the invitation letter, which often failed to reach its target, and the general distrust of postal correspondence. In contrast, participants were positive about the face-to-face canvassing approach. Participants expressed a lack of knowledge and understanding about CHD and their risk of developing it and felt there was a lack of clarity in the information provided in the mailing in terms of the process and value of screening. In contrast, direct face-to-face contact meant that outreach workers could explain what to expect. Participants felt that the procedure for uptake of screening was demanding and inflexible, but that the drop-in sessions employed by the community development project had a major impact on recruitment and retention.</p> <p><b>Conclusion:</b> Socio-economically disadvantaged individuals can be hard-to-reach; engagement requires strategies tailored to the needs of the target population rather than a population-wide approach.</p&gt

Patient and public involvement in pragmatic trials : online survey of corresponding authors of published trials

Acknowledgements The authors acknowledge Dr. Paxton Montgomery Moon, Alison Howie, Hayden Nix and Dr. Merrick Zwarenstein for their contributions to the data extraction. They also thank Drs. Bruno Giraudeau and Agnes Caille (University of Tours), Dr. Laura Hanson (University of North Carolina School of Medicine) and Dr. Jill Harrison (Brown University) for assistance with pilot testing of the survey questionnaire. Funding: This work was supported by the Canadian Institutes of Health Research through the Project Grant competition (competitive, peer-reviewed), award number PJT-153045, and the National Institute of Aging ( NIA) of the National Institutes of Health under Award Number U54AG063546, which funds NIA Imbedded Pragmatic Alzheimer’s Disease and Related Dementias Clinical Trials Collaboratory ( NIA IMPACT Collaboratory). The funders had no role in the study design; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the article for publication.Peer reviewedPublisher PD

Systematic techniques for assisting recruitment to trials (START): study protocol for embedded, randomized controlled trials

BACKGROUND: Randomized controlled trials play a central role in evidence-based practice, but recruitment of participants, and retention of them once in the trial, is challenging. Moreover, there is a dearth of evidence that research teams can use to inform the development of their recruitment and retention strategies. As with other healthcare initiatives, the fairest test of the effectiveness of a recruitment strategy is a trial comparing alternatives, which for recruitment would mean embedding a recruitment trial within an ongoing host trial. Systematic reviews indicate that such studies are rare. Embedded trials are largely delivered in an ad hoc way, with interventions almost always developed in isolation and tested in the context of a single host trial, limiting their ability to contribute to a body of evidence with regard to a single recruitment intervention and to researchers working in different contexts. METHODS/DESIGN: The Systematic Techniques for Assisting Recruitment to Trials (START) program is funded by the United Kingdom Medical Research Council (MRC) Methodology Research Programme to support the routine adoption of embedded trials to test standardized recruitment interventions across ongoing host trials. To achieve this aim, the program involves three interrelated work packages: (1) methodology - to develop guidelines for the design, analysis and reporting of embedded recruitment studies; (2) interventions - to develop effective and useful recruitment interventions; and (3) implementation - to recruit host trials and test interventions through embedded studies. DISCUSSION: Successful completion of the START program will provide a model for a platform for the wider trials community to use to evaluate recruitment interventions or, potentially, other types of intervention linked to trial conduct. It will also increase the evidence base for two types of recruitment intervention. TRIAL REGISTRATION: The START protocol covers the methodology for embedded trials. Each embedded trial is registered separately or as a substudy of the host trial

Mapping interactions with the chaperone network reveals factors that protect against tau aggregation.

A network of molecular chaperones is known to bind proteins ('clients') and balance their folding, function and turnover. However, it is often unclear which chaperones are critical for selective recognition of individual clients. It is also not clear why these key chaperones might fail in protein-aggregation diseases. Here, we utilized human microtubule-associated protein tau (MAPT or tau) as a model client to survey interactions between ~30 purified chaperones and ~20 disease-associated tau variants (~600 combinations). From this large-scale analysis, we identified human DnaJA2 as an unexpected, but potent, inhibitor of tau aggregation. DnaJA2 levels were correlated with tau pathology in human brains, supporting the idea that it is an important regulator of tau homeostasis. Of note, we found that some disease-associated tau variants were relatively immune to interactions with chaperones, suggesting a model in which avoiding physical recognition by chaperone networks may contribute to disease

The association between clinical integration of care and transfer of veterans with acute coronary syndromes from primary care VHA hospitals

BACKGROUND: Few studies report on the effect of organizational factors facilitating transfer between primary and tertiary care hospitals either within an integrated health care system or outside it. In this paper, we report on the relationship between degree of clinical integration of cardiology services and transfer rates of acute coronary syndrome (ACS) patients from primary to tertiary hospitals within and outside the Veterans Health Administration (VHA) system. METHODS: Prospective cohort study. Transfer rates were obtained for all patients with ACS diagnoses admitted to 12 primary VHA hospitals between 1998 and 1999. Binary variables measuring clinical integration were constructed for each primary VHA hospital reflecting: presence of on-site VHA cardiologist; referral coordinator at the associated tertiary VHA hospital; and/or referral coordinator at the primary VHA hospital. We assessed the association between the integration variables and overall transfer from primary to tertiary hospitals, using random effects logistic regression, controlling for clustering at two levels and adjusting for patient characteristics. RESULTS: Three of twelve hospitals had a VHA cardiologist on site, six had a referral coordinator at the tertiary VHA hospital, and four had a referral coordinator at the primary hospital. Presence of a VHA staff cardiologist on site and a referral coordinator at the tertiary VHA hospital decreased the likelihood of any transfer (OR 0.45, 95% CI 0.27–0.77, and 0.46, p = 0.002, CI 0.27–0.78). Conversely, having a referral coordinator at the primary VHA hospital increased the likelihood of transfer (OR 6.28, CI 2.92–13.48). CONCLUSIONS: Elements of clinical integration are associated with transfer, an important process in the care of ACS patients. In promoting optimal patient care, clinical integration factors should be considered in addition to patient characteristics

Effects of Growth Hormone and Pioglitazone in Viscerally Obese Adults with Impaired Glucose Tolerance: A Factorial Clinical Trial

OBJECTIVE: Recombinant human growth hormone (GH) and pioglitazone (PIO) in abdominally obese adults with impaired glucose tolerance were evaluated under the hypothesis that the combination attenuates GH-induced increases in glucose concentrations, reduces visceral adipose tissue (VAT), and improves insulin sensitivity over time. DESIGN: Randomized, double-blind, placebo-controlled, 2 × 2 factorial design. SETTING: Veterans Affairs Palo Alto Health Care System, Palo Alto, California, United States. PARTICIPANTS: 62 abdominally obese adults aged 40–75 with impaired glucose tolerance. INTERVENTIONS: GH (8 μg/kg/d, or placebo) and pioglitazone (30 mg/d, or placebo) for 40 wk. OUTCOME MEASURES: Baseline and after 40 wk of treatment, VAT content was quantified by CT scan, glucose tolerance was assessed using a 75-g oral glucose tolerance test, and insulin sensitivity was measured using steady-state plasma glucose levels obtained during insulin suppression test. RESULTS: Baseline: body mass index (BMI), plasma glucose, and visceral fat content were similar. 40 wk: visceral fat area declined 23.9 ± 7.4 cm(2) in GH group, mean difference from placebo: −28.1 cm(2) (95% CI −49.9 to −6.3 cm(2); p = 0.02). Insulin resistance declined 52 ± 11.8 mg/dl with PIO, mean difference from placebo of −58.8 mg/dl (95% CI −99.7 to −18.0 mg/dl; p = 0.01). VAT and SSPG declined with GH and PIO combined, mean differences from placebo of −31.4 cm(2) (95% CI −56.5 cm(2) to −6.3 cm(2); p = 0.02) and −55.3 mg/dl (95% CI −103.9 to −6.7 mg/dl; p = 0.02), respectively. Fasting plasma glucose increased transiently in GH group. No significant changes in BMI were observed. CONCLUSIONS: Addition of PIO to GH attenuated the short-term diabetogenic effect of GH; the drug combination reduced VAT and insulin resistance over time. GH plus PIO may have added benefit on body composition and insulin sensitivity in the metabolic syndrome

Evaluation of antibody response to Plasmodium falciparum in children according to exposure of Anopheles gambiae s.l or Anopheles funestus vectors

<p>Abstract</p> <p>Background</p> <p>In sub-Saharan areas, malaria transmission was mainly ensured by <it>Anopheles. gambiae </it>s.l. and <it>Anopheles. funestus </it>vectors. The immune response status to <it>Plasmodium falciparum </it>was evaluated in children living in two villages where malaria transmission was ensured by dissimilar species of <it>Anopheles </it>vectors (<it>An. funestus vs An. gambiae </it>s.l.).</p> <p>Methods</p> <p>A multi-disciplinary study was performed in villages located in Northern Senegal. Two villages were selected: Mboula village where transmission is strictly ensured by <it>An. gambiae </it>s.l. and Gankette Balla village which is exposed to several <it>Anopheles </it>species but where <it>An. funestus </it>is the only infected vector found. In each village, a cohort of 150 children aged from one to nine years was followed during one year and IgG response directed to schizont extract was determined by ELISA.</p> <p>Results</p> <p>Similar results of specific IgG responses according to age and <it>P. falciparum </it>infection were observed in both villages. Specific IgG response increased progressively from one-year to 5-year old children and then stayed high in children from five to nine years old. The children with <it>P. falciparum </it>infection had higher specific antibody responses compared to negative infection children, suggesting a strong relationship between production of specific antibodies and malaria transmission, rather than protective immunity. In contrast, higher variation of antibody levels according to malaria transmission periods were found in Mboula compared to Gankette Balla. In Mboula, the peak of malaria transmission was followed by a considerable increase in antibody levels, whereas low and constant anti-malaria IgG response was observed throughout the year in Gankette Balla.</p> <p>Conclusion</p> <p>This study shows that the development of anti-malaria antibody response was profoundly different according to areas where malaria exposure is dependent with different <it>Anopheles </it>species. These results are discussed according to i) the use of immunological tool for the evaluation of malaria transmission and ii) the influence of <it>Anopheles </it>vectors species on the regulation of antibody responses to <it>P. falciparum</it>.</p