87 research outputs found

    Young CSF restores oligodendrogenesis and memory in aged mice via Fgf17

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    Recent understanding of how the systemic environment shapes the brain throughout life has led to numerous intervention strategies to slow brain ageing1-3. Cerebrospinal fluid (CSF) makes up the immediate environment of brain cells, providing them with nourishing compounds4,5. We discovered that infusing young CSF directly into aged brains improves memory function. Unbiased transcriptome analysis of the hippocampus identified oligodendrocytes to be most responsive to this rejuvenated CSF environment. We further showed that young CSF boosts oligodendrocyte progenitor cell (OPC) proliferation and differentiation in the aged hippocampus and in primary OPC cultures. Using SLAMseq to metabolically label nascent mRNA, we identified serum response factor (SRF), a transcription factor that drives actin cytoskeleton rearrangement, as a mediator of OPC proliferation following exposure to young CSF. With age, SRF expression decreases in hippocampal OPCs, and the pathway is induced by acute injection with young CSF. We screened for potential SRF activators in CSF and found that fibroblast growth factor 17 (Fgf17) infusion is sufficient to induce OPC proliferation and long-term memory consolidation in aged mice while Fgf17 blockade impairs cognition in young mice. These findings demonstrate the rejuvenating power of young CSF and identify Fgf17 as a key target to restore oligodendrocyte function in the ageing brain

    Common diseases alter the physiological age-related blood microRNA profile

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    Aging is a key risk factor for chronic diseases of the elderly. MicroRNAs regulate post-transcriptional gene silencing through base-pair binding on their target mRNAs. We identified nonlinear changes in age-related microRNAs by analyzing whole blood from 1334 healthy individuals. We observed a larger influence of the age as compared to the sex and provide evidence for a shift to the 5' mature form of miRNAs in healthy aging. The addition of 3059 diseased patients uncovered pan-disease and disease-specific alterations in aging profiles. Disease biomarker sets for all diseases were different between young and old patients. Computational deconvolution of whole-blood miRNAs into blood cell types suggests that cell intrinsic gene expression changes may impart greater significance than cell abundance changes to the whole blood miRNA profile. Altogether, these data provide a foundation for understanding the relationship between healthy aging and disease, and for the development of age-specific disease biomarkers

    Multiomics modeling of the immunome, transcriptome, microbiome, proteome and metabolome adaptations during human pregnancy

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    Motivation Multiple biological clocks govern a healthy pregnancy. These biological mechanisms produce immunologic, metabolomic, proteomic, genomic and microbiomic adaptations during the course of pregnancy. Modeling the chronology of these adaptations during full-term pregnancy provides the frameworks for future studies examining deviations implicated in pregnancy-related pathologies including preterm birth and preeclampsia. Results We performed a multiomics analysis of 51 samples from 17 pregnant women, delivering at term. The datasets included measurements from the immunome, transcriptome, microbiome, proteome and metabolome of samples obtained simultaneously from the same patients. Multivariate predictive modeling using the Elastic Net (EN) algorithm was used to measure the ability of each dataset to predict gestational age. Using stacked generalization, these datasets were combined into a single model. This model not only significantly increased predictive power by combining all datasets, but also revealed novel interactions between different biological modalities. Future work includes expansion of the cohort to preterm-enriched populations and in vivo analysis of immune-modulating interventions based on the mechanisms identified. Availability and implementation Datasets and scripts for reproduction of results are available through: Https://nalab.stanford.edu/multiomics-pregnancy/

    Recent publications from the Alzheimer's Disease Neuroimaging Initiative: Reviewing progress toward improved AD clinical trials

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    INTRODUCTION: The Alzheimer's Disease Neuroimaging Initiative (ADNI) has continued development and standardization of methodologies for biomarkers and has provided an increased depth and breadth of data available to qualified researchers. This review summarizes the over 400 publications using ADNI data during 2014 and 2015. METHODS: We used standard searches to find publications using ADNI data. RESULTS: (1) Structural and functional changes, including subtle changes to hippocampal shape and texture, atrophy in areas outside of hippocampus, and disruption to functional networks, are detectable in presymptomatic subjects before hippocampal atrophy; (2) In subjects with abnormal β-amyloid deposition (Aβ+), biomarkers become abnormal in the order predicted by the amyloid cascade hypothesis; (3) Cognitive decline is more closely linked to tau than Aβ deposition; (4) Cerebrovascular risk factors may interact with Aβ to increase white-matter (WM) abnormalities which may accelerate Alzheimer's disease (AD) progression in conjunction with tau abnormalities; (5) Different patterns of atrophy are associated with impairment of memory and executive function and may underlie psychiatric symptoms; (6) Structural, functional, and metabolic network connectivities are disrupted as AD progresses. Models of prion-like spreading of Aβ pathology along WM tracts predict known patterns of cortical Aβ deposition and declines in glucose metabolism; (7) New AD risk and protective gene loci have been identified using biologically informed approaches; (8) Cognitively normal and mild cognitive impairment (MCI) subjects are heterogeneous and include groups typified not only by "classic" AD pathology but also by normal biomarkers, accelerated decline, and suspected non-Alzheimer's pathology; (9) Selection of subjects at risk of imminent decline on the basis of one or more pathologies improves the power of clinical trials; (10) Sensitivity of cognitive outcome measures to early changes in cognition has been improved and surrogate outcome measures using longitudinal structural magnetic resonance imaging may further reduce clinical trial cost and duration; (11) Advances in machine learning techniques such as neural networks have improved diagnostic and prognostic accuracy especially in challenges involving MCI subjects; and (12) Network connectivity measures and genetic variants show promise in multimodal classification and some classifiers using single modalities are rivaling multimodal classifiers. DISCUSSION: Taken together, these studies fundamentally deepen our understanding of AD progression and its underlying genetic basis, which in turn informs and improves clinical trial desig

    Central processing of behaviorally relevant odors in the awake rat, as revealed by Manganese-enhanced MRI

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    The aim of this thesis was to use MEMRI (manganese-enhanced magnetic resonance imaging) for studying the processing of behaviorally significant odors in the rat primary olfactory cortex, under conditions close to natural perception in awake animals. MEMRI is a method based on the detection of o functional and remanent contrast agent, manganese, which has proved to be valuable dor studying odor processing in the olfactory bulb. However , this method has mainly been used to trace neuronal pathways, but seldom to explore sensory functions. Here, we have conducted two studies to define the conditions of application of manganese and to optimize processing of MEMRI images. Based on these methodological developments, we have then used MEMRI to investigate the activation of central olfactory structures following exposure of awake rats to biologically relevant odors (food and predator odors compared to a control situation). MEMRI revealed that a predator is processed differently from the control situation in the primary olfactory cortex. Fos immunolabeling in the anterior piriform cortex corroborated this result. Altogether, MEMRI and Fos results suggest that olfactory processing may rely on both the intensity of activation and the size of neuronal populations recruited. Finally, MEMRI revealed that the olfactory message, crucial for survival, is asymmetrically processed in the brain. Methodological and scientific advances brought by this thesis will be useful for better understanding brain olfactory processing.L'objectif de cette thèse est d'utiliser MEMRI (manganese-enhanced magnetic resonance imaging) pour étudier le traitement d'odeurs signifiantes dans le cortex olfactif primaire de rats dans les conditions les plus proches de la perception naturelle. MEMRI est une méthode fondée sur la détection d'un agent de contraste fonctionnel et rémanent de l'activité neuronale, le manganèse, qui a prouvé son efficacité pour montrer le traitement différencié d'odeurs dans le bulbe olfactif chez l'animal vigile. Cependant, cette technique a été surtout utilisée pour tracer les voies neuronales, mais relativement peu pour explorer des fonctions sensorielles. C'est pourquoi nous avons conduit deux études visant l'une à définir les conditions d'application du manganèse et l'autre à optimiser le traitement des images MEMRI, avant d'aborder la question biologique proprement dite. S'appuyant sur ces développement méthodologiques, nous avons ensuite utilisé MEMRI pour étudier les variations du traitement d'odeurs signifiantes (odeurs de nourriture et de prédateur comparées à une situation de contrôle) dans le cortex olfactif primaire de rats. Nous avons montré que le traitement cérébral d'une odeur de prédateur est différent de celui de la situation de contrôle dans le cortex olfactif primaire. Nous avons confirmé ce résultat par immunomarquage Fos dans le cortex piriforme. Mis ensemble, les résultats de MEMRI et Fos suggèrent que le traitement cérébral d'une odeur peut varier en terme de taille de populations de neurone recrutés ainsi qu'en termes d'intensité de l'activation de ces neurones. Enfin, les résultats MEMRI montrent qu'un message olfactif crucial, pour la survie, est traité asymétriquement dans le cerveau. Les avancées méthodologiques et scientifiques qu'apporte cette thèse ouvrent la voie à une meilleure compréhension du traitement cérébral des odeurs

    Traitement cérébral d'odeurs biologiquement signifiantes, révélé chez le rat par imagerie RMN fonctionnelle du manganèse

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    The aim of this thesis was to use MEMRI (manganese-enhanced magnetic resonance imaging) for studying the processing of behaviorally significant odors in the rat primary olfactory cortex, under conditions close to natural perception in awake animals. MEMRI is a method based on the detection of o functional and remanent contrast agent, manganese, which has proved to be valuable dor studying odor processing in the olfactory bulb. However , this method has mainly been used to trace neuronal pathways, but seldom to explore sensory functions. Here, we have conducted two studies to define the conditions of application of manganese and to optimize processing of MEMRI images. Based on these methodological developments, we have then used MEMRI to investigate the activation of central olfactory structures following exposure of awake rats to biologically relevant odors (food and predator odors compared to a control situation). MEMRI revealed that a predator is processed differently from the control situation in the primary olfactory cortex. Fos immunolabeling in the anterior piriform cortex corroborated this result. Altogether, MEMRI and Fos results suggest that olfactory processing may rely on both the intensity of activation and the size of neuronal populations recruited. Finally, MEMRI revealed that the olfactory message, crucial for survival, is asymmetrically processed in the brain. Methodological and scientific advances brought by this thesis will be useful for better understanding brain olfactory processing.L'objectif de cette thèse est d'utiliser MEMRI (manganese-enhanced magnetic resonance imaging) pour étudier le traitement d'odeurs signifiantes dans le cortex olfactif primaire de rats dans les conditions les plus proches de la perception naturelle. MEMRI est une méthode fondée sur la détection d'un agent de contraste fonctionnel et rémanent de l'activité neuronale, le manganèse, qui a prouvé son efficacité pour montrer le traitement différencié d'odeurs dans le bulbe olfactif chez l'animal vigile. Cependant, cette technique a été surtout utilisée pour tracer les voies neuronales, mais relativement peu pour explorer des fonctions sensorielles. C'est pourquoi nous avons conduit deux études visant l'une à définir les conditions d'application du manganèse et l'autre à optimiser le traitement des images MEMRI, avant d'aborder la question biologique proprement dite. S'appuyant sur ces développement méthodologiques, nous avons ensuite utilisé MEMRI pour étudier les variations du traitement d'odeurs signifiantes (odeurs de nourriture et de prédateur comparées à une situation de contrôle) dans le cortex olfactif primaire de rats. Nous avons montré que le traitement cérébral d'une odeur de prédateur est différent de celui de la situation de contrôle dans le cortex olfactif primaire. Nous avons confirmé ce résultat par immunomarquage Fos dans le cortex piriforme. Mis ensemble, les résultats de MEMRI et Fos suggèrent que le traitement cérébral d'une odeur peut varier en terme de taille de populations de neurone recrutés ainsi qu'en termes d'intensité de l'activation de ces neurones. Enfin, les résultats MEMRI montrent qu'un message olfactif crucial, pour la survie, est traité asymétriquement dans le cerveau. Les avancées méthodologiques et scientifiques qu'apporte cette thèse ouvrent la voie à une meilleure compréhension du traitement cérébral des odeurs

    Central processing of behaviorally relevant odors in the awake rat, as revealed by Manganese-enhanced MRI

    No full text
    L'objectif de cette thèse est d'utiliser MEMRI (manganese-enhanced magnetic resonance imaging) pour étudier le traitement d'odeurs signifiantes dans le cortex olfactif primaire de rats dans les conditions les plus proches de la perception naturelle. MEMRI est une méthode fondée sur la détection d'un agent de contraste fonctionnel et rémanent de l'activité neuronale, le manganèse, qui a prouvé son efficacité pour montrer le traitement différencié d'odeurs dans le bulbe olfactif chez l'animal vigile. Cependant, cette technique a été surtout utilisée pour tracer les voies neuronales, mais relativement peu pour explorer des fonctions sensorielles. C'est pourquoi nous avons conduit deux études visant l'une à définir les conditions d'application du manganèse et l'autre à optimiser le traitement des images MEMRI, avant d'aborder la question biologique proprement dite. S'appuyant sur ces développement méthodologiques, nous avons ensuite utilisé MEMRI pour étudier les variations du traitement d'odeurs signifiantes (odeurs de nourriture et de prédateur comparées à une situation de contrôle) dans le cortex olfactif primaire de rats. Nous avons montré que le traitement cérébral d'une odeur de prédateur est différent de celui de la situation de contrôle dans le cortex olfactif primaire. Nous avons confirmé ce résultat par immunomarquage Fos dans le cortex piriforme. Mis ensemble, les résultats de MEMRI et Fos suggèrent que le traitement cérébral d'une odeur peut varier en terme de taille de populations de neurone recrutés ainsi qu'en termes d'intensité de l'activation de ces neurones. Enfin, les résultats MEMRI montrent qu'un message olfactif crucial, pour la survie, est traité asymétriquement dans le cerveau. Les avancées méthodologiques et scientifiques qu'apporte cette thèse ouvrent la voie à une meilleure compréhension du traitement cérébral des odeurs.The aim of this thesis was to use MEMRI (manganese-enhanced magnetic resonance imaging) for studying the processing of behaviorally significant odors in the rat primary olfactory cortex, under conditions close to natural perception in awake animals. MEMRI is a method based on the detection of o functional and remanent contrast agent, manganese, which has proved to be valuable dor studying odor processing in the olfactory bulb. However , this method has mainly been used to trace neuronal pathways, but seldom to explore sensory functions. Here, we have conducted two studies to define the conditions of application of manganese and to optimize processing of MEMRI images. Based on these methodological developments, we have then used MEMRI to investigate the activation of central olfactory structures following exposure of awake rats to biologically relevant odors (food and predator odors compared to a control situation). MEMRI revealed that a predator is processed differently from the control situation in the primary olfactory cortex. Fos immunolabeling in the anterior piriform cortex corroborated this result. Altogether, MEMRI and Fos results suggest that olfactory processing may rely on both the intensity of activation and the size of neuronal populations recruited. Finally, MEMRI revealed that the olfactory message, crucial for survival, is asymmetrically processed in the brain. Methodological and scientific advances brought by this thesis will be useful for better understanding brain olfactory processing
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