49 research outputs found

    HspB5 Activates a Neuroprotective Glial Cell Response in Experimental Tauopathy

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    Progressive neuronal death during tauopathies is associated with aggregation of modified, truncated or mutant forms of tau protein. Such aggregates are neurotoxic, promote spreading of tau aggregation, and trigger release of pro-inflammatory factors by glial cells. Counteracting such pathogenic effects of tau by simultaneously inhibiting protein aggregation as well as pro-inflammatory glial cell responses would be of significant therapeutic interest. Here, we examined the use of the small heat-shock protein HspB5 for this purpose. As a molecular chaperone, HspB5 counteracts aggregation of a wide range of abnormal proteins. As a TLR2 agonist, it selectively activates protective responses by CD14-expressing myeloid cells including microglia. We show that intracerebral infusion of HspB5 in transgenic mice with selective neuronal expression of mutant human P301S tau has significant neuroprotective effects in the superficial, frontal cortical layers. Underlying these effects at least in part, HspB5 induces several potent neuroprotective mediators in both astrocytes and microglia including neurotrophic factors and increased potential for removal of glutamate. Together, these findings highlight the potentially broad therapeutic potential of HspB5 in neurodegenerative proteinopathies

    Small heat shock proteins are induced during multiple sclerosis lesion development in white but not grey matter

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    INTRODUCTION: The important protective role of small heat-shock proteins (HSPs) in regulating cellular survival and migration, counteracting protein aggregation, preventing apoptosis, and regulating inflammation in the central nervous system is now well-recognized. Yet, their role in the neuroinflammatory disorder multiple sclerosis (MS) is largely undocumented. With the exception of alpha B-crystallin (HSPB5), little is known about the roles of small HSPs in disease. RESULTS: Here, we examined the expression of four small HSPs during lesion development in MS, focussing on their cellular distribution, and regional differences between white matter (WM) and grey matter (GM). It is well known that MS lesions in these areas differ markedly in their pathology, with substantially more intense blood-brain barrier damage, leukocyte infiltration and microglial activation typifying WM but not GM lesions. We analysed transcript levels and protein distribution profiles for HSPB1, HSPB6, HSPB8 and HSPB11 in MS lesions at different stages, comparing them with normal-appearing brain tissue from MS patients and non-neurological controls. During active stages of demyelination in WM, and especially the centre of chronic active MS lesions, we found significantly increased expression of HSPB1, HSPB6 and HSPB8, but not HSPB11. When induced, small HSPs were exclusively found in astrocytes but not in oligodendrocytes, microglia or neurons. Surprisingly, while the numbers of astrocytes displaying high expression of small HSPs were markedly increased in actively demyelinating lesions in WM, no such induction was observed in GM lesions. This difference was particularly obvious in leukocortical lesions covering both WM and GM areas. CONCLUSIONS: Since induction of small HSPs in astrocytes is apparently a secondary response to damage, their differential expression between WM and GM likely reflects differences in mediators that accompany demyelination in either WM or GM during MS. Our findings also suggest that during MS, cortical structures fail to benefit from the protective actions of small HSPs. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s40478-015-0267-2) contains supplementary material, which is available to authorized users

    Skin marker-based versus bone morphology-based coordinate systems of the hindfoot and forefoot

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    Segment coordinate systems (CSs) of marker-based multi-segment foot models are used to measure foot kinematics, however their relationship to the underlying bony anatomy is barely studied. The aim of this study was to compare marker-based CSs (MCSs) with bone morphology-based CSs (BCSs) for the hindfoot and forefoot. Markers were placed on the right foot of fifteen healthy adults according to the Oxford, Rizzoli and Amsterdam Foot Model (OFM, RFM and AFM, respectively). A CT scan was made while the foot was loaded in a simulated weight-bearing device. BCSs were based on axes of inertia. The orientation difference between BCSs and MCSs was quantified in helical and 3D Euler angles. To determine whether the marker models were able to capture inter-subject variability in bone poses, linear regressions were performed. Compared to the hindfoot BCS, all MCSs were more toward plantar flexion and internal rotation, and RFM was also oriented toward more inversion. Compared to the forefoot BCS, OFM and RFM were oriented more toward dorsal and plantar flexion, respectively, and internal rotation, while AFM was not statistically different in the sagittal and transverse plane. In the frontal plane, OFM was more toward eversion and RFM and AFM more toward inversion compared to BCS. Inter-subject bone pose variability was captured with RFM and AFM in most planes of the hindfoot and forefoot, while this variability was not captured by OFM. When interpreting multi-segment foot model data it is important to realize that MCSs and BCSs do not always align.</p

    Exploring Data Provenance in Handwritten Text Recognition Infrastructure: Sharing and Reusing Ground Truth Data, Referencing Models, and Acknowledging Contributions. Starting the Conversation on How We Could Get It Done

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    This paper discusses best practices for sharing and reusing Ground Truth in Handwritten Text Recognition infrastructures, as well as ways to reference and acknowledge contributions to the creation and enrichment of data within these systems. We discuss how one can place Ground Truth data in a repository and, subsequently, inform others through HTR-United. Furthermore, we want to suggest appropriate citation methods for ATR data, models, and contributions made by volunteers. Moreover, when using digitised sources (digital facsimiles), it becomes increasingly important to distinguish between the physical object and the digital collection. These topics all relate to the proper acknowledgement of labour put into digitising, transcribing, and sharing Ground Truth HTR data. This also points to broader issues surrounding the use of machine learning in archival and library contexts, and how the community should begin to acknowledge and record both contributions and data provenance

    LEARN 2 MOVE 7-12 years: a randomized controlled trial on the effects of a physical activity stimulation program in children with cerebral palsy

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    <p>Abstract</p> <p>Background</p> <p>Regular participation in physical activities is important for all children to stay fit and healthy. Children with cerebral palsy have reduced levels of physical activity, compared to typically developing children. The aim of the LEARN 2 MOVE 7-12 study is to improve physical activity by means of a physical activity stimulation program, consisting of a lifestyle intervention and a fitness training program.</p> <p>Methods/Design</p> <p>This study will be a 6-month single-blinded randomized controlled trial with a 6-month follow up. Fifty children with spastic cerebral palsy, aged 7 to 12 years, with Gross Motor Function Classification System levels I-III, will be recruited in pediatric physiotherapy practices and special schools for children with disabilities. The children will be randomly assigned to either the intervention group or control group. The children in the control group will continue with their regular pediatric physiotherapy, and the children in the intervention group will participate in a 6-month physical activity stimulation program. The physical activity stimulation program consists of a 6-month lifestyle intervention, in combination with a 4-month fitness training program. The lifestyle intervention includes counseling the child and the parents to adopt an active lifestyle through Motivational Interviewing, and home-based physiotherapy to practise mobility-related activities in the daily situation. Data will be collected just before the start of the intervention (T0), after the 4-month fitness training program (T4), after the 6-month lifestyle intervention (T6), and after six months of follow-up (T12). Primary outcomes are physical activity, measured with the StepWatch Activity Monitor and with self-reports. Secondary outcomes are fitness, capacity of mobility, social participation and health-related quality of life. A random coefficient analysis will be performed to determine differences in treatment effect between the control group and the intervention group, with primary outcomes and secondary outcomes as the dependent variables.</p> <p>Discussion</p> <p>This is the first study that investigates the effect of a combined lifestyle intervention and fitness training on physical activity. Temporary effects of the fitness training are expected to be maintained by changes to an active lifestyle in daily life and in the home situation.</p> <p>Trial registration</p> <p>This study is registered in the Dutch Trial Register as NTR2099.</p

    Exploring data provenance in handwritten text recognition infrastructure:Sharing and reusing ground truth data, referencing models, and acknowledging contributions. Starting the conversation on how we could get it done

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    This paper discusses best practices for sharing and reusing Ground Truth in Handwritten Text Recognition infrastructures, and ways to reference and acknowledge contributions to the creation and enrichment of data within these Machine Learning systems. We discuss how one can publish Ground Truth data in a repository and, subsequently, inform others. Furthermore, we suggest appropriate citation methods for HTR data, models, and contributions made by volunteers. Moreover, when using digitised sources (digital facsimiles), it becomes increasingly important to distinguish between the physical object and the digital collection. These topics all relate to the proper acknowledgement of labour put into digitising, transcribing, and sharing Ground Truth HTR data. This also points to broader issues surrounding the use of Machine Learning in archival and library contexts, and how the community should begin toacknowledge and record both contributions and data provenance

    Mechanisms in the development of multiple sclerosis lesions: reconciling autoimmune and neurodegenerative factors

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    Both immune-mediated and neurodegenerative processes play a role in the pathogenesis of multiple sclerosis (MS). There is still considerable debate, however, on how to link these two seemingly unrelated elements in disease. It has also remained unclear how the immune system can be involved without harboring any obvious myelin-directed abnormality in MS patients. Here, we propose that the unique properties of a small heat shock protein, HSPB5, can help reconcile the role of the immune system with the neurodegenerative element in MS, and explain the absence of any peripheral immune abnormality in patients. By being selectively induced as a protective stress protein in oligodendrocytes, and subsequently triggering activation of nearby microglia, HSPB5 accumulation translates neurodegenerative signals into a local innate immune response. The immune-regulatory profile of HSPB5-activated microglia, as well as animal model data, indicate that the HSPB5-induced innate response is neuroprotective. However, the presence of pro-inflammatory HSPB5-reactive memory T cells in the human immune repertoire, a unique feature among mammals, can subvert this response. Recruited by the innate response, such T cells respond to the accumulation of HSPB5 by an adaptive immune response, dominated by IFN-Îł production, that ultimately overwhelms the originally protective microglial response, and culminates in tissue damage. Thus, HSPB5 accumulation caused by neurodegeneration can provoke a destructive local adaptive response of an otherwise normal immune system. This scenario is fully consistent with known causative factors and the pathology of MS, and with the effects of various therapies. It also helps explain why MS develops only in humans

    Heat Shock Proteins: Old and Novel Roles in Neurodegenerative Diseases in the Central Nervous System

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    Heat shock proteins (HSPs) are families of molecular chaperones that play important homeostatic functions in the central nervous system (CNS) by preventing protein misfolding, promoting degradation of improperly folded proteins, and protecting against apoptosis and inflammatory damage especially during hyperthermia, hypoxia, or oxidative stress. Under stress conditions, HSPs are upregulated to protect cells from damage that accumulates during ageing as well as pathological conditions. An important, yet frequently overlooked function of some HSPs is their ability to function as extracellular messengers (also termed chaperokines) that modulate immune responses within the CNS. Given the strong association between protein aggregation, innate immune cell activation and neurodegeneration, the expression and roles of HSPs in the CNS is attracting attention in many neurodegenerative disorders including inflammatory diseases such as multiple sclerosis, protein folding diseases such as Alzheimer's disease and amyotrophic lateral sclerosis, and genetic white matter diseases. This is especially so since several studies show that HSPs act therapeutically by modulating innate immune activation and may thus serve as neuroprotective agents. Here we review the evidence linking HSPs with neurodegenerative disorders in humans and the experimental animal models of these disorders. We discuss the mechanisms by which HSPs protect cells, and how the knowledge of their endogenous functions can be exploited to treat disorders of the CNS

    Toll-Like Receptors 2 and 3 Agonists Differentially Affect Oligodendrocyte Survival, Differentiation, and Myelin Membrane Formation

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    Toll-like receptors (TLRs) play a key role in controlling innate immune responses to a wide variety of pathogen-associated molecules as well as endogenous signals. In addition, TLR expression within nonimmune cells has been recognized as as modulator of cell behavior. In this study we have addressed the question of whether functional TLRs are expressed on oligodendrocytes, the myelinating cells of the central nervous system. Primary cultures of rat oligodendrocytes at different maturation stages were found to express TLR2 and, to lesser extent, TLR3. Immunocytochemical analysis revealed that both TLRs were localized at the cell body and primary processes and were excluded from myelin-like membranes. Interestingly, innate immune receptor ligands were able to modulate oligodendrocyte survival, differentiation, and myelin-like membrane formation, indicating that TLRs on oligodendrocytes are functional. In highly purified oligodendrocytes cultures, the TLR2 agonist zymosan promoted survival, differentiation, and myelin-like membrane formation, whereas poly-I:C, a TLR3 ligand, was a potent inducer of apoptosis. Together, these data indicate that, in addition to other neural cell types, also oligodendrocytes express functional TLRs, which play a role in regulating various aspects of oligodendrocyte behavior. (C) 2011 Wiley Periodicals, Inc

    Non-neuronal cells in ALS: Role of glial, immune cells and blood-CNS barriers

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    Neurological dysfunction and motor neuron degeneration in amyotrophic lateral sclerosis (ALS) is strongly associated with neuroinflammation reflected by activated microglia and astrocytes in the CNS. In ALS endogenous triggers in the CNS such as aggregated protein and misfolded proteins activate a pathogenic response by innate immune cells. However, there is also strong evidence for a neuroprotective immune response in ALS. Emerging evidence also reveals changes in the peripheral adaptive immune responses as well as alterations in the blood brain barrier that may aid traffic of lymphocytes and antibodies into the CNS. Understanding the triggers of neuroinflammation is key to controlling neuronal loss. Here, we review the current knowledge regarding the roles of non-neuronal cells as well as the innate and adaptive immune responses in ALS. Existing ALS animal models, in particular genetic rodent models, are very useful to study the underlying pathogenic mechanisms of motor neuron degeneration. We also discuss the approaches used to target the pathogenic immune responses and boost the neuroprotective immune pathways as novel immunotherapies for ALS
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