Investigation into pathogenic mechanisms leading to neuro-glial-vascular damage and cognitive decline in a mouse model of vascular cognitive impairment

Vascular cognitive impairment (VCI) refers to the contribution of cerebrovascular disease to a spectrum of cognitive impairments, ranging from subjective cognitive decline to dementia. Compromised cerebral blood flow (CBF) has been heavily implicated in the pathogenesis of cerebrovascular disease, however, the key underlying mechanisms remain to be fully elucidated. Bilateral common carotid artery stenosis (BCAS) is a surgical method in which micro-coils are applied permanently to both carotid arteries to reduce CBF. The BCAS mouse model recapitulates many of the pathological and functional hallmarks of VCI, making it a valuable experimental model. A prominent feature of the BCAS model is a robust increase in white matter microglial numbers, which are significantly associated with cognitive impairments. The first aim of this thesis was to test the hypothesis that microglial proliferation directly leads to white matter damage and cognitive impairment following BCAS. BCAS surgery was found to elicit a significant and persistent reduction in CBF, alongside increased microglial proliferation. Pharmacological inhibition of microglial proliferation, through GW2580 treatment, prevented microglial proliferation, reduced microglial lysosomal expression, preserved white matter integrity, and restored spatial learning deficits. The second aim was to investigate, using the Cx3Cr1 eGFP microglial reporter line and intravital multiphoton imaging, structural and functional changes within microglial cells following BCAS. The additional pathogenic effects of amyloidosis as a co-morbidity using the transgenic App23 mouse model were also assessed. Microglial structure and process motility were found to be unaltered, at 1-week following BCAS, within both Cx3Cr1 eGFP/+ and Cx3Cr1 eGFP/+App23 mice. Following 3-months of BCAS, microglial density was found to be unaltered, alongside intact neurovascular coupling responses and spatial learning, although, spatial memory was impaired within Cx3Cr1 eGFP/+ mice. Microglial density was also found to be unchanged within Cx3Cr1 eGFP/+App23 mice following 3-months of BCAS. Neurovascular coupling, however, was significantly impaired within Cx3Cr1 eGFP/+App23 mice following BCAS surgery. Spatial learning and memory deficits were found within Cx3Cr1 eGFP/+App23 mice alone, with no additional BCAS mediated deficit. As a means of explaining the lack of microglial response within the Cx3Cr1 eGFP/+ mice, qPCR analysis was carried out and confirmed a ≈5-fold reduction in Cx3Cr1 receptor expression. Considerable evidence has implicated cerebrovascular dysfunction as a pivotal mechanism in the pathophysiology of VCI and dementia. The studies in chapter 3 aimed to test the hypothesis that BCAS causes vascular dysfunction leading to the onset of neuro-glial-vascular damage. Multiphoton imaging of C57BL/6J wild-type mice found significantly reduced RBC velocity alongside impaired arterial pulsation, and increased leukocyte trafficking, 1-month following BCAS surgery. In conclusion, the work described within this thesis demonstrates that microglial proliferation plays a causative role in white matter damage and cognitive decline following BCAS, and that this can be successfully targeted to reverse pathological damage and functional deficits. Furthermore, Cx3Cr1 receptor signalling was found to play a significant role in the regulation of microglial responses following BCAS. Finally, BCAS was found to not simply be a model of reduced CBF, with impairments in arterial pulsation and increased endothelial activation providing a new framework to contextualise BCAS mediated effects in future studies

Xyloglucan is released by plants and promotes soil particle aggregation

Soil is a crucial component of the biosphere and is a major sink for organic carbon. Plant roots are known to release a wide range of carbon-based compounds into soils, including polysaccharides, but the functions of these are not known in detail. Using a monoclonal antibody to plant cell wall xyloglucan, we show that this polysaccharide is secreted by a wide range of angiosperm roots, and relatively abundantly by grasses. It is also released from the rhizoids of liverworts, the earliest diverging lineage of land plants. Using analysis of water-stable aggregate size, dry dispersion particle analysis and scanning electron microscopy, we show that xyloglucan is effective in increasing soil particle aggregation, a key factor in the formation and function of healthy soils. To study the possible roles of xyloglucan in the formation of soils, we analysed the xyloglucan contents of mineral soils of known age exposed upon the retreat of glaciers. These glacial forefield soils had significantly higher xyloglucan contents than detected in a UK grassland soil. We propose that xyloglucan released from plant rhizoids/roots is an effective soil particle aggregator and may, in this role, have been important in the initial colonization of land

Exploring FlyBase Data Using QuickSearch.

FlyBase (flybase.org) is the primary online database of genetic, genomic, and functional information about Drosophila species, with a major focus on the model organism Drosophila melanogaster. The long and rich history of Drosophila research, combined with recent surges in genomic-scale and high-throughput technologies, mean that FlyBase now houses a huge quantity of data. Researchers need to be able to rapidly and intuitively query these data, and the QuickSearch tool has been designed to meet these needs. This tool is conveniently located on the FlyBase homepage and is organized into a series of simple tabbed interfaces that cover the major data and annotation classes within the database. This unit describes the functionality of all aspects of the QuickSearch tool. With this knowledge, FlyBase users will be equipped to take full advantage of all QuickSearch features and thereby gain improved access to data relevant to their research. © 2016 by John Wiley & Sons, Inc

Impaired Glymphatic Function and Pulsation Alterations in a Mouse Model of Vascular Cognitive Impairment

ACKNOWLEDGMENTS Schematic diagrams in Figures 2, 8 are created withBiorender.com. FUNDING We gratefully acknowledge the grant support from the Alzheimer’s Society (152 (PG-157); 290 (AS-PG-15b-018); 228 (AS-DTC-2014-017), 314 (AS –PhD-16-006), and Alzheimer’s Research United Kingdom (ART-PG2010-3; ARUK-PG2013- 22; ARUK-PG2016B-6), and The University of Edinburgh Centre for Cognitive Ageing and Cognitive Epidemiology, part of the cross council Lifelong Health and Wellbeing Initiative (G0700704/84698). ML and JB are funded by an Alzheimer’s Society Scotland Doctoral Training Programme and RS Macdonald Trust. ML was also funded by a China Scholarship Council (CSC)/University of Edinburgh scholarship.Peer reviewedPublisher PD

FlyBase 2.0: the next generation.

FlyBase (flybase.org) is a knowledge base that supports the community of researchers that use the fruit fly, Drosophila melanogaster, as a model organism. The FlyBase team curates and organizes a diverse array of genetic, molecular, genomic, and developmental information about Drosophila. At the beginning of 2018, 'FlyBase 2.0' was released with a significantly improved user interface and new tools. Among these important changes are a new organization of search results into interactive lists or tables (hitlists), enhanced reference lists, and new protein domain graphics. An important new data class called 'experimental tools' consolidates information on useful fly strains and other resources related to a specific gene, which significantly enhances the ability of the Drosophila researcher to design and carry out experiments. With the release of FlyBase 2.0, there has also been a restructuring of backend architecture and a continued development of application programming interfaces (APIs) for programmatic access to FlyBase data. In this review, we describe these major new features and functionalities of the FlyBase 2.0 site and how they support the use of Drosophila as a model organism for biological discovery and translational research

Evaluating a streamlined clinical tool and educational outreach intervention for health care workers in Malawi: the PALM PLUS case study

<p>Abstract</p> <p>Background</p> <p>Nearly 3 million people in resource-poor countries receive antiretrovirals for the treatment of HIV/AIDS, yet millions more require treatment. Key barriers to treatment scale up are shortages of trained health care workers, and challenges integrating HIV/AIDS care with primary care.</p> <p>The research</p> <p>PALM PLUS (Practical Approach to Lung Health and HIV/AIDS in Malawi) is an intervention designed to simplify and integrate existing Malawian national guidelines into a single, simple, user-friendly guideline for mid-level health care workers. Training utilizes a peer-to-peer educational outreach approach. Research is being undertaken to evaluate this intervention to generate evidence that will guide future decision-making for consideration of roll out in Malawi. The research consists of a cluster randomized trial in 30 public health centres in Zomba District that measures the effect of the intervention on staff satisfaction and retention, quality of patient care, and costs through quantitative, qualitative and health economics methods.</p> <p>Results and outcomes</p> <p>In the first phase of qualitative inquiry respondents from intervention sites demonstrated in-depth knowledge of PALM PLUS compared to those from control sites. Participants in intervention sites felt that the PALM PLUS tool empowered them to provide better health services to patients. Interim staff retention data shows that there were, on average, 3 to 4 staff departing from the control and intervention sites per month. Additional qualitative, quantitative and economic analyses are planned.</p> <p>The partnership</p> <p>Dignitas International and the Knowledge Translation Unit at the University of Cape Town Lung Institute have led the adaptation and development of the PALM PLUS intervention, using experience gained through the implementation of the South African precursor, PALSA PLUS. The Malawian partners, REACH Trust and the Research Unit at the Ministry of Health, have led the qualitative and economic evaluations. Dignitas and Ministry of Health have facilitated interaction with implementers and policy-makers.</p> <p>Challenges and successes</p> <p>This initiative is an example of South-South knowledge translation between South Africa and Malawi, mediated by a Canadian academic-NGO hybrid. Our success in developing and rolling out PALM PLUS in Malawi suggests that it is possible to adapt and implement this intervention for use in other resource-limited settings.</p

INHIBITING CSF1R ALLEVIATES CEREBROVASCULAR WHITE MATTER DISEASE AND COGNITIVE IMPAIRMENT

White matter abnormalities, related to poor cerebral perfusion, are a core feature of small vessel cerebrovascular disease, and critical determinants of vascular cognitive impairment and dementia. Despite this importance there is a lack of treatment options. Proliferation of microglia producing an expanded, reactive population and associated neuroinflammatory alterations have been implicated in the onset and progression of cerebrovascular white matter disease, in patients and in animal models, suggesting that targeting microglial proliferation may exert protection. Colony-stimulating factor-1 receptor (CSF1R) is a key regulator of microglial proliferation. We found that the expression of CSF1R/Csf1r and other markers indicative of increased microglial abundance are significantly elevated in damaged white matter in human cerebrovascular disease and in a clinically relevant mouse model of chronic cerebral hypoperfusion and vascular cognitive impairment. Using the mouse model, we investigated long-term pharmacological CSF1R inhibition, via GW2580, and demonstrated that the expansion of microglial numbers in chronic hypoperfused white matter is prevented. Transcriptomic analysis of hypoperfused white matter tissue showed enrichment of microglial and inflammatory gene sets, including phagocytic genes that were the predominant expression modules modified by CSF1R inhibition. Further, CSF1R inhibition attenuated hypoperfusion-induced white matter pathology and rescued spatial learning impairments and to a lesser extent cognitive flexibility. Overall, this work suggests that inhibition of CSF1R and microglial proliferation mediates protection against chronic cerebrovascular white matter pathology and cognitive deficits. Our study nominates CSF1R as a target for the treatment of vascular cognitive disorders with broader implications for treatment of other chronic white matter diseases.<br/

FlyBase at 25: looking to the future.

Since 1992, FlyBase (flybase.org) has been an essential online resource for the Drosophila research community. Concentrating on the most extensively studied species, Drosophila melanogaster, FlyBase includes information on genes (molecular and genetic), transgenic constructs, phenotypes, genetic and physical interactions, and reagents such as stocks and cDNAs. Access to data is provided through a number of tools, reports, and bulk-data downloads. Looking to the future, FlyBase is expanding its focus to serve a broader scientific community. In this update, we describe new features, datasets, reagent collections, and data presentations that address this goal, including enhanced orthology data, Human Disease Model Reports, protein domain search and visualization, concise gene summaries, a portal for external resources, video tutorials and the FlyBase Community Advisory Group