206 research outputs found

    Differential splicing of neuronal genes in a Trem2*R47H mouse model mimics alterations associated with Alzheimer\u27s disease.

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    BACKGROUND: Molecular characterization of late-onset Alzheimer\u27s disease (LOAD), the leading cause of age-related dementia, has revealed transcripts, proteins, and pathway alterations associated with disease. Assessing these postmortem signatures of LOAD in experimental model systems can further elucidate their relevance to disease origins and progression. Model organisms engineered with human genetic factors further link these signatures to disease-associated variants, especially when studies are designed to leverage homology across species. Here we assess differential gene splicing patterns in aging mouse models carrying humanized APOE4 and/or the Trem2*R47H variant on a C57BL/6J background. We performed a differential expression of gene (DEG) and differential splicing analyses on whole brain transcriptomes at multiple ages. To better understand the difference between differentially expressed and differentially spliced genes, we evaluated enrichment of KEGG pathways and cell-type specific gene signatures of the adult brain from each alteration type. To determine LOAD relevance, we compared differential splicing results from mouse models with multiple human AD splicing studies. RESULTS: We found that differentially expressed genes in Trem2*R47H mice were significantly enriched in multiple AD-related pathways, including immune response, osteoclast differentiation, and metabolism, whereas differentially spliced genes were enriched for neuronal related functions, including GABAergic synapse and glutamatergic synapse. These results were reinforced by the enrichment of microglial genes in DEGs and neuronal genes in differentially spliced genes in Trem2*R47H mice. We observed significant overlap between differentially spliced genes in Trem2*R47H mice and brains from human AD subjects. These effects were absent in APOE4 mice and suppressed in APOE4.Trem2*R47H double mutant mice relative to Trem2*R47H mice. CONCLUSIONS: The cross-species observation that alternative splicing observed in LOAD are present in Trem2*R47H mouse models suggests a novel link between this candidate risk gene and molecular signatures of LOAD in neurons and demonstrates how deep molecular analysis of new genetic models links molecular disease outcomes to a human candidate gene

    The APOEΔ3/Δ4 Genotype Drives Distinct Gene Signatures in the Cortex of Young Mice

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    Introduction: Restrictions on existing APOE mouse models have impacted research toward understanding the strongest genetic risk factor contributing to Alzheimer\u27s disease (AD) and dementia, APOEΔ4 , by hindering observation of a key, common genotype in humans - APOEΔ3/Δ4 . Human studies are typically underpowered to address APOEΔ4 allele risk as the APOEΔ4/Δ4 genotype is rare, which leaves human and mouse research unsupported to evaluate the APOEΔ3/Δ4 genotype on molecular and pathological risk for AD and dementia. Methods: As a part of MODEL-AD, we created and validated new versions of humanized APOEΔ3/Δ3 and APOEΔ4/Δ4 mouse strains that, due to unrestricted breeding, allow for the evaluation of the APOEΔ3/Δ4 genotype. As biometric measures are often translatable between mouse and human, we profiled circulating lipid concentrations. We also performed transcriptional profiling of the cerebral cortex at 2 and 4 months (mos), comparing APOEΔ3/Δ4 and APOEΔ4/Δ4 to the reference APOEΔ3/Δ3 using linear modeling and WGCNA. Further, APOE mice were exercised and compared to litter-matched sedentary controls, to evaluate the interaction between APOEΔ4 and exercise at a young age. Results: Expression of human APOE isoforms were confirmed in APOEΔ3/Δ3, APOEΔ3/Δ4 and APOEΔ4/Δ4 mouse brains. At two mos, cholesterol composition was influenced by sex, but not APOE genotype. Results show that the APOEΔ3/Δ4 and APOEΔ4/Δ4 genotype exert differential effects on cortical gene expression. APOEΔ3/Δ4 uniquely impacts \u27hormone regulation\u27 and \u27insulin signaling,\u27 terms absent in APOEΔ4/Δ4 data. At four mos, cholesterol and triglyceride levels were affected by sex and activity, with only triglyceride levels influenced by APOE genotype. Linear modeling revealed APOEΔ3/Δ4 , but not APOEΔ4/Δ4 , affected \u27extracellular matrix\u27 and \u27blood coagulation\u27 related terms. We confirmed these results using WGCNA, indicating robust, yet subtle, transcriptional patterns. While there was little evidence of APOE genotype by exercise interaction on the cortical transcriptome at this young age, running was predicted to affect myelination and gliogenesis, independent of APOE genotype with few APOE genotype-specific affects identified. Discussion: APOEΔ4 allele dosage-specific effects were observed in circulating lipid levels and cortical transcriptional profiles. Future studies are needed to establish how these data may contribute to therapeutic development in APOEΔ3/Δ4 and APOEΔ4/Δ4 dementia patients

    Groundwater microbiology of an urban open‐loop ground source heat pump with high methane

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    Ground source heat pumps (GSHPs) are low carbon alternatives to gas boilers for decarbonising heating. Open-loop GSHP systems abstract groundwater, pass it though a heat exchanger and return it to ground or surface water. Groundwater samples from the top and base of an abstraction and a recharge borehole of an open-loop GSHP system in Cardiff, UK were assessed, and compared to two local boreholes in the same aquifer. Groundwater samples were taken when the GSHP system was active (once) and inactive (twice) and analysed for changes in geochemistry, viable cell counts and microbial community (16S rRNA gene sequencing). The GSHP had a distinct geochemistry and microbial community compared to the control boreholes, and the abstraction borehole showed greater variability than the recharge borehole. The microbial community of the GSHP system showed an increase in relative abundance of genera involved in oxidation of methane and methylated compounds, of which Methylotenera was the most abundant (up to 83.9% of 16S rRNA gene sequences). There were also changes in genera associated with nitrification (Nitrospira, Nitrosomonas) and those with potential for sulphur and iron cycling (Rhodoferax). Methane concentration was analysed out after identification of methylotrophs and found that methane concentrations were up to 2855 ÎŒg L-1, likely having had a significant impact on the bacterial communities present. Understanding the microbiology and biogeochemisty of GSHP systems provides insight into potential issues with local infrastructure and long-term system performance, and support modelling to maximise efficient and sustainable use of the subsurface

    Aortic arch baroreceptor stimulation in an experimental goat model: a novel method to lower blood pressure

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    The effect of aortic baroreceptor stimulation on blood pressure manipulation was assessed using the goat species Capra aegagrus hircus. The aim of this study was to manipulate blood pressure with future intention to treat high blood pressure in humans. The ages of the animals ranged from 6 months to 2 years. A standard anesthesia protocol was used. A lateral thoracotomy was performed to gain access to the aortic arch. Data was collected with the Vigileo system. Pre stimulation blood pressure was compared with maximum post stimulation blood pressure values. Results were analyzed with the Wilcoxon signed rank test. In the study 38 animals were enrolled. Baroreceptor stimulation was performed for each animal using 3 different electrodes each of which emits an electrical impulse. In the pilot phase of the study, the median baseline blood pressure prior to stimulation of the baroreceptors was 110.8 mmHg. After stimulation the median blood pressure decreased to 88 mmHg. The average decrease in blood pressure was 22.8 mmHg. This decrease of blood pressure after stimulation of the baroreceptors is statistically significant (p < 0.0001) and the proof of concept was shown. During the extended phase all three probes had a significant effect on blood pressure lowering (p < 0.0001). The study confirmed that aortic baroreceptor stimulation has an effect on blood pressure lowering. This is a novel field of blood pressure manipulation. The hemodynamic effects of long-term aortic baroreceptor stimulation are unknown. Further investigations need to be done to determine whether a similar effect can be induced in different species such as primates and humans

    Overcoming the barriers to greater public engagement

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    Integrating science communication training into an undergraduate research project encourages greater academic involvement in public engagement, maximizes audience size, and provides high-quality research data

    Brain endothelial miR-146a negatively modulates T-cell adhesion through repressing multiple targets to inhibit NF-ÎșB activation.

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    Pro-inflammatory cytokine-induced activation of nuclear factor, NF-ÎșB has an important role in leukocyte adhesion to, and subsequent migration across, brain endothelial cells (BECs), which is crucial for the development of neuroinflammatory disorders such as multiple sclerosis (MS). In contrast, microRNA-146a (miR-146a) has emerged as an anti-inflammatory molecule by inhibiting NF-ÎșB activity in various cell types, but its effect in BECs during neuroinflammation remains to be evaluated. Here, we show that miR-146a was upregulated in microvessels of MS-active lesions and the spinal cord of mice with experimental autoimmune encephalomyelitis. In vitro, TNFα and IFNÎł treatment of human cerebral microvascular endothelial cells (hCMEC/D3) led to upregulation of miR-146a. Brain endothelial overexpression of miR-146a diminished, whereas knockdown of miR-146a augmented cytokine-stimulated adhesion of T cells to hCMEC/D3 cells, nuclear translocation of NF-ÎșB, and expression of adhesion molecules in hCMEC/D3 cells. Furthermore, brain endothelial miR-146a modulates NF-ÎșB activity upon cytokine activation through targeting two novel signaling transducers, RhoA and nuclear factor of activated T cells 5, as well as molecules previously identified, IL-1 receptor-associated kinase 1, and TNF receptor-associated factor 6. We propose brain endothelial miR-146a as an endogenous NF-ÎșB inhibitor in BECs associated with decreased leukocyte adhesion during neuroinflammation

    A novel systems biology approach to evaluate mouse models of late-onset Alzheimer\u27s disease.

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    BACKGROUND: Late-onset Alzheimer\u27s disease (LOAD) is the most common form of dementia worldwide. To date, animal models of Alzheimer\u27s have focused on rare familial mutations, due to a lack of frank neuropathology from models based on common disease genes. Recent multi-cohort studies of postmortem human brain transcriptomes have identified a set of 30 gene co-expression modules associated with LOAD, providing a molecular catalog of relevant endophenotypes. RESULTS: This resource enables precise gene-based alignment between new animal models and human molecular signatures of disease. Here, we describe a new resource to efficiently screen mouse models for LOAD relevance. A new NanoString nCounterÂź Mouse AD panel was designed to correlate key human disease processes and pathways with mRNA from mouse brains. Analysis of the 5xFAD mouse, a widely used amyloid pathology model, and three mouse models based on LOAD genetics carrying APOE4 and TREM2*R47H alleles demonstrated overlaps with distinct human AD modules that, in turn, were functionally enriched in key disease-associated pathways. Comprehensive comparison with full transcriptome data from same-sample RNA-Seq showed strong correlation between gene expression changes independent of experimental platform. CONCLUSIONS: Taken together, we show that the nCounter Mouse AD panel offers a rapid, cost-effective and highly reproducible approach to assess disease relevance of potential LOAD mouse models

    Results from the GeoERA MUSE shallow geothermal project – UK Cardiff pilot area

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    Shallow geothermal energy systems deployment will play an important part in decarbonisation of heating and cooling of buildings. This trend will stimulate research into ground physical, thermal and hydraulic properties and impacts on urban aquifers and infrastructures. Moreover, subsurface heat extraction must be perceived as reliable, sustainable and equitable to create an environment for social acceptance and uptake of geothermal technologies. The EU H2020-funded GeoERA ‘MUSE’ project (2018-2021), involved 16 Geological Surveys, who shared methods and developed harmonised workflows for the evaluation of shallow geothermal resources in European urban areas (Götzl et al., EGC 2022). The project deployed and tested ground characterisation and geophysical monitoring techniques, monitored GSHP schemes, analysed the local market situation, produced fact sheets, made policy recommendations, and developed adaptive management strategies. The research included in-field monitoring studies in 14 urban pilot areas across Europe, including three UK urban pilot areas; Cardiff in south Wales, Glasgow in west Scotland and Colchester in east England. This paper summarises the result with a focus on the Cardiff area

    Genomic characterisation of EΌ-Myc mouse lymphomas identifies Bcor as a Myc co-operative tumour-suppressor gene

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    The EΌ-Myc mouse is an extensively used model of MYC driven malignancy; however to date there has only been partial characterization of MYC co-operative mutations leading to spontaneous lymphomagenesis. Here we sequence spontaneously arising EΌ-Myc lymphomas to define transgene architecture, somatic mutations, and structural alterations. We identify frequent disruptive mutations in the PRC1-like component and BCL6-corepressor gene Bcor. Moreover, we find unexpected concomitant multigenic lesions involving Cdkn2a loss and other cancer genes including Nras, Kras and Bcor. These findings challenge the assumed two-hit model of EΌ-Myc lymphoma and demonstrate a functional in vivo role for Bcor in suppressing tumorigenesis.We acknowledge the following funding agencies: Leukaemia Foundation of Australia, Arrow Bone Marrow Transplant Foundation, National Health and Medical Research Council Australia, Cancer Council Victoria, Victorian Cancer Agency, Australian Cancer Research Foundation, Peter MacCallum Cancer Centre Foundation, National Institutes of Health
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