•CD8+ T-cells infiltrate the brain in aging and human AD pathology.•CD8+ T-cells can successfully be ablated from blood and brain using an anti-CD8 antibody approach.•AD transgenic mice lacking CD8+ ...T-cells show altered neuronal- and synapse-related gene expression in the hippocampus.
Neuroinflammation is a major contributor to disease progression in Alzheimer’s disease (AD) and is characterized by the activity of brain resident glial cells, in particular microglia cells. However, there is increasing evidence that peripheral immune cells infiltrate the brain at certain stages of AD progression and shape disease pathology. We recently identified CD8+ T-cells in the brain parenchyma of APP-PS1 transgenic mice being tightly associated with microglia as well as with neuronal structures. The functional role of CD8+ T-cells in the AD brain is however completely unexplored. Here, we demonstrate increased numbers of intra-parenchymal CD8+ T-cells in human AD post-mortem hippocampus, which was replicated in APP-PS1 mice. Also, aged WT mice show a remarkable infiltration of CD8+ T-cells, which was more pronounced and had an earlier onset in APP-PS1 mice. To address their functional relevance in AD, we successfully ablated the pool of CD8+ T-cells in the blood, spleen and brain from 12 months-old APP-PS1 and WT mice for a total of 4 weeks using an anti-CD8 antibody treatment. While the treatment at this time of disease stage did neither affect the cognitive outcome nor plaque pathology, RNAseq analysis of the hippocampal transcriptome from APP-PS1 mice lacking CD8+ T-cells revealed highly altered neuronal- and synapse-related gene expression including an up-regulation for neuronal immediate early genes (IEGs) such as the Activity Regulated Cytoskeleton Associated Protein (Arc) and the Neuronal PAS Domain Protein 4 (Npas4). Gene ontology enrichment analysis illustrated that the biological processes “regulation of neuronal synaptic plasticity” and the cellular components “postsynapses” were over-represented upon CD8+ T-cell ablation. Additionally, Kegg pathway analysis showed up-regulated pathways for “calcium signaling”, “long-term potentiation”, “glutamatergic synapse” and “axon guidance”. Therefore, we conclude that CD8+ T-cells infiltrate the aged and AD brain and that brain CD8+ T-cells might directly contribute to neuronal dysfunction in modulating synaptic plasticity. Further analysis will be essential to uncover the exact mechanism of how CD8+ T-cells modulate the neuronal landscape and thereby contribute to AD pathology.
Adult neurogenesis is a target for brain rejuvenation as well as regeneration in aging and disease. Numerous approaches showed efficacy to elevate neurogenesis in rodents, yet translation into ...therapies has not been achieved. Here, we introduce a novel human TGFβ-RII (Transforming Growth Factor—Receptor Type II) specific LNA-antisense oligonucleotide (“locked nucleotide acid”—“NVP-13”), which reduces TGFβ-RII expression and downstream receptor signaling in human neuronal precursor cells (ReNcell CX® cells)
in vitro
. After we injected cynomolgus non-human primates repeatedly i.th. with NVP-13 in a preclinical regulatory 13-week GLP-toxicity program, we could specifically downregulate TGFβ-RII mRNA and protein
in vivo
. Subsequently, we observed a dose-dependent upregulation of the neurogenic niche activity within the hippocampus and subventricular zone: human neural progenitor cells showed significantly (up to threefold over control) enhanced differentiation and cell numbers. NVP-13 treatment modulated canonical and non-canonical TGFβ pathways, such as MAPK and PI3K, as well as key transcription factors and epigenetic factors involved in stem cell maintenance, such as MEF2A and pFoxO3. The latter are also dysregulated in clinical neurodegeneration, such as amyotrophic lateral sclerosis. Here, we provide for the first time
in vitro
and
in vivo
evidence for a novel translatable approach to treat neurodegenerative disorders by modulating neurogenesis.
Le microbiote intestinal (MI) participe à la digestion et au métabolisme de nombreux nutriments en libérant des métabolites dans le tube digestif, dont certains gagnent la circulation sanguine et ...traversent la barrière hémato-encéphalique, interagissant ainsi directement avec le cerveau. Cependant, les connaissances sur le lien entre MI et santé cérébrale sont en grande partie précliniques, et peu d’études ont porté sur les métabolites microbiotiques circulants et le vieillissement cognitif chez l’homme. L’objectif de cette étude était d’analyser et de valider, dans un cas-témoin niché dans une grande cohorte de sujets âgés, l’association entre des dizaines de métabolites sanguins dérivés du MI et le déclin cognitif au long cours.
Cette étude met à profit les données de la cohorte des trois-cités (3C, Bordeaux, Dijon et Montpellier) chez des personnes âgées de 65 ans ou plus à l’inclusion. Les participants non déments au moment du prélèvement sanguin et dont la cognition a été mesurée de façon répétée au cours des 12 années suivantes étaient éligibles pour le cas-témoin niché. Un échantillon de découverte a été défini dans 3C Bordeaux, incluant les 209 participants avec la pente de déclin cognitif la plus importante, appariés à 209 témoins avec une cognition plus stable (pente>pente médiane) et de même âge, sexe et niveau d’études. Un échantillon de validation a été défini de façon similaire dans 3C Dijon (210 paires cas-témoin). Une analyse en métabolomique ciblée a permis de quantifier 76 métabolites liés à l’alimentation et potentiellement dérivés du MI. L’association entre chaque métabolite et le déclin cognitif a été étudiée dans l’échantillon de découverte en utilisant des régressions logistiques conditionnelles. Les métabolites dont la P-valeur corrigée pour les tests multiples (FDR) était≤0,15 ont été testés pour réplication.
7 métabolites étaient associés au déclin cognitif avec une P-FDR≤0,15 dans l’échantillon de découverte : la phénylacétylglutamine, l’acide indole-lactique, l’acide kynurénique, la bétaïne, la vitamine B5, le propionate et le 3,4-DHPV-S. Seul le propionate était répliqué (OR=1,26, 95 % IC 1,02 ;1,55). Cette association était atténuée de façon importante après ajustement sur les facteurs de risque cardiométaboliques dans l’échantillon de validation (une population à risque vasculaire plus important que la population de découverte).
Cette étude suggère une relation délétère entre l’acide propionique circulant et le déclin cognitif. Le rôle de la santé cardiométabolique dans cette relation mérite d’être approfondi.
BACKGROUND: Brain lipid metabolism appears critical for cognitive aging, but whether alterations in the lipidome relate to cognitive decline remains unclear at the system level. METHODS: We studied ...participants from the Three-City study, a multicentric cohort of older persons, free of dementia at time of blood sampling, and who provided repeated measures of cognition over 12 subsequent years. We measured 189 serum lipids from 13 lipid classes using shotgun lipidomics in a case-control sample on cognitive decline (matched on age, sex and level of education) nested within the Bordeaux study center (discovery, n = 418). Associations with cognitive decline were investigated using bootstrapped penalized regression, and tested for validation in the Dijon study center (validation, n = 314). FINDINGS: Among 17 lipids identified in the discovery stage, lower levels of the triglyceride TAG50:5, and of four membrane lipids (sphingomyelin SM40:2,2, phosphatidylethanolamine PE38:5(18:1/20:4), ether-phosphatidylethanolamine PEO34:3(16:1/18:2), and ether-phosphatidylcholine PCO34:1(16:1/18:0)), and higher levels of PCO32:0(16:0/16:0), were associated with greater odds of cognitive decline, and replicated in our validation sample. INTERPRETATION: These findings indicate that in the blood lipidome of non-demented older persons, a specific profile of lipids involved in membrane fluidity, myelination, and lipid rafts, is associated with subsequent cognitive decline. FUNDING: The complete list of funders is available at the end of the manuscript, in the Acknowledgement section.
Abstract
BACKGROUND
Orthotopic xenograft studies strongly promote the development of targeted/personalized cancer therapies to improve the still poor life expectancy of glioblastoma patients. In ...recent years, the tumor microenvironment has increasingly become subject of investigations, as it could have an impact on the progression of the cancer. However, examination of the tumor microenvironment with currently available methods inevitably causes trauma that might compromise the reliability of the obtained data. We aimed to implement an atraumatic access to human glioblastoma with cerebral Open Flow Microperfusion (cOFM) by implantation of xenograft cells in rodent’s brain of different species (mouse and rat) with intact blood brain barrier (BBB) and subsequent development of a xenograft glioblastoma at the interface between the cOFM probe and the surrounding brain tissue. Thereafter, we used the cOFM probe to collect interstitial fluid (ISF) from the tumor microenvironment for metabolome and biomarker assessment.
MATERIAL AND METHODS
Human glioma cells were implanted at a well-defined position into immune-deficient rodent’s brain via cOFM or syringe. Characteristics of the mature tumors from both groups were assessed. ISF from tumor microenvironment was collected without further traumatization by using cOFM, and the collected tumor ISF samples were analyzed using a UHPLC-HRMS metabolomics platform. A targeted (Biocrates MxP®) and an untargeted (Metaboanalyst) approach were used to analyze the metabolomics data.
RESULTS
For the first time xenograft cells were successfully introduced into rodent brain with intact BBB using cOFM, and the tumor tissue that developed around the cOFM probe was unaffected by the presence of the probe. Thereby, an atraumatic access to the tumor was created. The mature cOFM-induced tumors resembled the syringe-induced ones and showed typical features of human glioblastoma. The cOFM sampling procedure did not alter tumor morphology.
CONCLUSION
This novel atraumatic access to human glioblastoma in a rodent brain was used to collect ISF from functional tumor microenvironment in vivo without trauma generation. The thereby generated reliable data are likely to promote drug research, biomarker identification, and enable investigation of the BBB of a functional tumor.
Alzheimer's disease (AD) and aging are associated with platelet hyperactivity. However, the mechanisms underlying abnormal platelet function in AD and aging are yet poorly understood.
To explore the ...molecular profile of AD and aged platelets, we investigated platelet activation (i.e., CD62P expression), proteome and transcriptome in AD patients, non-demented elderly, and young individuals as controls.
AD, aged and young individuals showed similar levels of platelet activation based on CD62P expression. However, AD and aged individuals had a proteomic signature suggestive of increased platelet activation compared with young controls. Transcriptomic profiling suggested the dysregulation of proteolytic machinery involved in regulating platelet function, particularly the ubiquitin-proteasome system in AD and autophagy in aging. The functional implication of these transcriptomic alterations remains unclear and requires further investigation.
Our data strengthen the evidence of enhanced platelet activation in aging and provide a first glimpse of the platelet transcriptomic changes occurring in AD.
Issue Title: Special Issue on Biomorphic Robotics RHex is an untethered, compliant leg hexapod robot that travels at better than one body length per second over terrain few other robots can negotiate ...at all. Inspired by biomechanics insights into arthropod locomotion, RHex uses a clock excited alternating tripod gait to walk and run in a highly maneuverable and robust manner. We present empirical data establishing that RHex exhibits a dynamical ("bouncing") gait--its mass center moves in a manner well approximated by trajectories from a Spring Loaded Inverted Pendulum (SLIP)--characteristic of a large and diverse group of running animals, when its central clock, body mass, and leg stiffnesses are appropriately tuned. The SLIP template can function as a useful control guide in developing more complex autonomous locomotion behaviors such as registration via visual servoing, local exploration via visual odometry, obstacle avoidance, and, eventually, global mapping and localization.PUBLICATION ABSTRACT
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