91 research outputs found

    Loss of capillary pericytes and the blood–brain barrier in white matter in poststroke and vascular dementias and Alzheimer’s disease

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    White matter (WM) disease is associated with disruption of the gliovascular unit, which involves breach of the blood‐brain barrier (BBB). We quantified pericytes as components of the gliovascular unit and assessed their status in vascular and other common dementias. Immunohistochemical and immunofluorescent methods were developed to assess the distribution and quantification of pericytes connected to the frontal lobe WM capillaries. Pericytes with a nucleus were identified by collagen 4 (COL4) and platelet derived growth factor receptor‐β (PDGFR‐β) antibodies with further verification using PDGFR‐β specific ELISA. We evaluated a total of 124 post‐mortem brains from subjects with post‐stroke dementia (PSD), vascular dementia (VaD), Alzheimer’s disease (AD), AD‐VaD (Mixed), and post‐stroke non‐demented (PSND) stroke survivors as well as normal ageing controls. COL4 and PDGFR‐β reactive pericytes adopted the characteristic “crescent” or nodule‐like shapes around capillary walls. We estimated densities of pericyte somata to be 225 ±38 and 200 ±13 (SEM) per COL4 mm2 area or 2.0 ±0.1 and 1.7 ±0.1 per mm capillary length in young and older ageing controls. Remarkably, WM pericytes were reduced by ~35‐45 percent in the frontal lobe of PSD, VaD, Mixed and AD subjects compared to PSND and controls subjects (P<0.001). We also found pericyte numbers were correlated with PDGFR‐β reactivity in the WM. Our results first demonstrate a reliable method to quantify COL4‐positive pericytes and then indicate that deep WM pericytes are decreased across different dementias including PSD, VaD, Mixed and AD. Our findings suggest that down regulation of pericytes is associated with the disruption of the BBB in the deep WM in several ageing‐related dementias

    Multiscale multifactorial approaches for engineering tendon substitutes

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    The physiology of tendons and the continuous strains experienced daily make tendons very prone to injury. Excessive and prolonged loading forces and aging also contribute to the onset and progression of tendon injuries, and conventional treatments have limited efficacy in restoring tendon biomechanics. Tissue engineering and regenerative medicine (TERM) approaches hold the promise to provide therapeutic solutions for injured or damaged tendons despite the challenging cues of tendon niche and the lack of tendon-specific factors to guide cellular responses and tackle regeneration. The roots of engineering tendon substitutes lay in multifactorial approaches from adequate stem cells sources and environmental stimuli to the construction of multiscale 3D scaffolding systems. To achieve such advanced tendon substitutes, incremental strategies have been pursued to more closely recreate the native tendon requirements providing structural as well as physical and chemical cues combined with biochemical and mechanical stimuli to instruct cell behavior in 3D architectures, pursuing mechanically competent constructs with adequate maturation before implantation.Authors acknowledge the project “Accelerating tissue engineering and personalized medicine discoveries by the integration of key enabling nanotechnologies, marinederived biomaterials and stem cells,” supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). Authors acknowledge the H2020 Achilles Twinning Project No. 810850, and also the European Research Council CoG MagTendon No. 772817, and the FCT Project MagTT PTDC/CTM-CTM/ 29930/2017 (POCI-01-0145-FEDER-29930

    Genomic and Metabolomic Insights into the Natural Product Biosynthetic Diversity of a Feral-Hog-Associated Brevibacillus laterosporus Strain

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    The authors thank C. A. Mitchell for advice concerning the organization of the biosynthetic gene clusters in B. laterosporus PE36. We acknowledge J. Villemarete for providing access to the feral hog for sampling. Author contributions Conceived and designed the experiments: BSS RHC. Performed the experiments: CMT BWS JBK LSLP DRP. Analyzed the data: CMT BWS JBK LSLP DRP BSS RHC. Contributed reagents/materials/analysis tools: CMT BWS DRP. Wrote the paper: CMT BWS BSS RHC.Bacteria associated with mammals are a rich source of microbial biodiversity; however, little is known concerning the abilities of these microbes to generate secondary metabolites. This report focuses on a bacterium isolated from the ear of a feral hog from southwestern Oklahoma, USA. The bacterium was identified as a new strain (PE36) of Brevibacillus latersporus, which was shown via genomic analysis to contain a large number of gene clusters presumably involved in secondary metabolite biosynthesis. A scale-up culture of B. latersporus PE36 yielded three bioactive compounds that inhibited the growth of methicillin-resistant Staphylococcus aureus (basiliskamides A and B and 12-methyltetradecanoic acid). Further studies of the isolate's secondary metabolome provided both new (auripyrazine) and previously-described pyrazine-containing compounds. In addition, a new peptidic natural product (auriporcine) was purified that was determined to be composed of a polyketide unit, two L-proline residues, two D-leucine residues, one L-leucine residue, and a reduced L-phenylalanine (L-phenylalanol). An examination of the genome revealed two gene clusters that are likely responsible for generating the basiliskamides and auriporcine. These combined genomic and chemical studies confirm that new and unusual secondary metabolites can be obtained from the bacterial associates of wild mammals.Ye

    Conserved Genes Act as Modifiers of Invertebrate SMN Loss of Function Defects

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    Spinal Muscular Atrophy (SMA) is caused by diminished function of the Survival of Motor Neuron (SMN) protein, but the molecular pathways critical for SMA pathology remain elusive. We have used genetic approaches in invertebrate models to identify conserved SMN loss of function modifier genes. Drosophila melanogaster and Caenorhabditis elegans each have a single gene encoding a protein orthologous to human SMN; diminished function of these invertebrate genes causes lethality and neuromuscular defects. To find genes that modulate SMN function defects across species, two approaches were used. First, a genome-wide RNAi screen for C. elegans SMN modifier genes was undertaken, yielding four genes. Second, we tested the conservation of modifier gene function across species; genes identified in one invertebrate model were tested for function in the other invertebrate model. Drosophila orthologs of two genes, which were identified originally in C. elegans, modified Drosophila SMN loss of function defects. C. elegans orthologs of twelve genes, which were originally identified in a previous Drosophila screen, modified C. elegans SMN loss of function defects. Bioinformatic analysis of the conserved, cross-species, modifier genes suggests that conserved cellular pathways, specifically endocytosis and mRNA regulation, act as critical genetic modifiers of SMN loss of function defects across species

    Linking the genome to phenotypes in wheat: Advances in technologies and concepts

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    It is ten years since Volume 1 of The World Wheat Book was completed and the intervening years have seen many changes in the world economy, in agriculture in the countries where wheat is grown, and major developments in the techniques of wheat breeding. This second volume therefore updates the first volume by adding to the countries discussed, giving an update on agronomy and cropping practices, and reviewing the technological advances in wheat breeding techniques. The opening chapters summarise the history of wheat growing, the development of wheat breeding, and the current status of breeding in the countries covered. The next set of chapters looks at agronomy and cropping practices in a wide range of wheat growing regions across the world. The third set of chapters records the latest advances in wheat breeding, looking at concepts and strategies as well as current and developing techniques. The fourth set reviews the developing end uses. The final group of chapters examines specific biotic and abiotic threats from viruses, insect pests and diseases. This book is subtitled A History of Wheat Breeding. It would be even more accurate to say that it records and discusses the continuing history of wheat breeding
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