scholarly journals Tau pathology spreads between anatomically-connected regions of the brain and is modulated by a LRRK2 mutation

2020 ◽  
Author(s):  
Michael X. Henderson ◽  
Eli J. Cornblath ◽  
Howard L. Li ◽  
Lakshmi Changolkar ◽  
Bin Zhang ◽  
...  
Keyword(s):  
Expression Patterns ◽  
Network Models ◽  
Spatial Proximity ◽  
Spatiotemporal Pattern ◽  
Diagnostic Feature ◽  
Tau Pathology ◽  
Anatomical Connectivity ◽  
Regional Vulnerability ◽  
Kinetics Of ◽  
The Brain

ABSTRACTTau pathology is a diagnostic feature of Alzheimer’s disease (AD) but is also a prominent feature of Parkinson’s disease (PD), including genetic forms of PD with mutations in leucine-rich repeat kinase 2 (LRRK2). In both diseases, tau pathology is progressive and correlates with cognitive decline. Neuropathological staging studies in humans and mouse models have suggested that tau spreads through the brain, but it is unclear how neuroanatomical connections, spatial proximity, and regional vulnerability contribute to pathology spread. Further, it is unknown how mutations in the LRRK2 gene may modulate susceptibility to tau pathology’s initiation or spread. In this study, we used seed-based models of tauopathy to capture spatiotemporal patterns of pathology in mice. Following the injection of AD brain-derived tau into the brains of non-transgenic mice, tau pathology spreads progressively through the brain in a spatiotemporal pattern that is well-explained by anatomical connectivity. We validated and compared network models based on diffusion along anatomical connections to predict tau spread, estimate regional vulnerability to tau pathology, and investigate gene expression patterns related to regional vulnerability. We further investigated tau pathology spread in mice harboring a mutation in LRRK2 and found that while tau pathology spread is still constrained by anatomical connectivity, it spreads preferentially in a retrograde direction to regions that are otherwise resilient in wildtype mice. This study provides a quantitative demonstration that tau pathology spreads along anatomical connections, explores the kinetics of this spread, and provides a platform for investigating the effect of genetic risk factors and treatments on the progression of tauopathies.

scholarly journals Computational modeling of tau pathology spread reveals patterns of regional vulnerability and the impact of a genetic risk factor

2021 ◽  
Vol 7 (24) ◽  
pp. eabg6677
Author(s):  
Eli J. Cornblath ◽  
Howard L. Li ◽  
Lakshmi Changolkar ◽  
Bin Zhang ◽  
Hannah J. Brown ◽  
...  
Keyword(s):  
Expression Patterns ◽  
Brain Regions ◽  
Spatial Proximity ◽  
Leucine Rich Repeat ◽  
Related Gene ◽  
Tau Pathology ◽  
Anatomical Connectivity ◽  
Regional Vulnerability ◽  
The Impact ◽  
The Brain

Neuropathological staging studies have suggested that tau pathology spreads through the brain in Alzheimer’s disease (AD) and other tauopathies, but it is unclear how neuroanatomical connections, spatial proximity, and regional vulnerability contribute. In this study, we seed tau pathology in the brains of nontransgenic mice with AD tau and quantify pathology development over 9 months in 134 brain regions. Network modeling of pathology progression shows that diffusion through the connectome is the best predictor of tau pathology patterns. Further, deviations from pure neuroanatomical spread are used to estimate regional vulnerability to tau pathology and identify related gene expression patterns. Last, we show that pathology spread is altered in mice harboring a mutation in leucine-rich repeat kinase 2. While tau pathology spread is still constrained by anatomical connectivity in these mice, it spreads preferentially in a retrograde direction. This study provides a framework for understanding neuropathological progression in tauopathies.

scholarly journals Experimental evidence for the age dependence of tau protein spread in the brain

2019 ◽  
Vol 5 (6) ◽  
pp. eaaw6404 ◽  
Author(s):  
Susanne Wegmann ◽  
Rachel E. Bennett ◽  
Louis Delorme ◽  
Ashley B. Robbins ◽  
Miwei Hu ◽  
...  
Keyword(s):  
Tau Protein ◽  
Brain Region ◽  
Age Dependence ◽  
Tau Pathology ◽  
Related Factors ◽  
Age Related ◽  
Regional Vulnerability ◽  
Related Risk ◽  
Old Mice ◽  
The Brain

The incidence of Alzheimer’s disease (AD), which is characterized by progressive cognitive decline that correlates with the spread of tau protein aggregation in the cortical mantle, is strongly age-related. It could be that age predisposes the brain for tau misfolding and supports the propagation of tau pathology. We tested this hypothesis using an experimental setup that allowed for exploration of age-related factors of tau spread and regional vulnerability. We virally expressed human tau locally in entorhinal cortex (EC) neurons of young or old mice and monitored the cell-to-cell tau protein spread by immunolabeling. Old animals showed more tau spreading in the hippocampus and adjacent cortical areas and accumulated more misfolded tau in EC neurons. No misfolding, at any age, was observed in the striatum, a brain region mostly unaffected by tangles. Age and brain region dependent tau spreading and misfolding likely contribute to the profound age-related risk for sporadic AD.

scholarly journals A Sphingosine 1-Phosphate Gradient Is Linked to the Cerebral Recruitment of T Helper and Regulatory T Helper Cells during Acute Ischemic Stroke

2020 ◽  
Vol 21 (17) ◽  
pp. 6242
Author(s):  
Alexandra Lucaciu ◽  
Hannah Kuhn ◽  
Sandra Trautmann ◽  
Nerea Ferreirós ◽  
Helmuth Steinmetz ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Expression Patterns ◽  
Treg Cells ◽  
Artery Occlusion ◽  
T Helper ◽  
Sphingosine 1 Phosphate ◽  
Cerebral Artery Occlusion ◽  
Kinetics Of ◽  
The Brain

Emerging evidence suggests a complex relationship between sphingosine 1-phosphate (S1P) signaling and stroke. Here, we show the kinetics of S1P in the acute phase of ischemic stroke and highlight accompanying changes in immune cells and S1P receptors (S1PR). Using a C57BL/6 mouse model of middle cerebral artery occlusion (MCAO), we assessed S1P concentrations in the brain, plasma, and spleen. We found a steep S1P gradient from the spleen towards the brain. Results obtained by qPCR suggested that cells expressing the S1PR type 1 (S1P1+) were the predominant population deserting the spleen. Here, we report the cerebral recruitment of T helper (TH) and regulatory T (TREG) cells to the ipsilateral hemisphere, which was associated with differential regulation of cerebral S1PR expression patterns in the brain after MCAO. This study provides insight that the S1P-S1PR axis facilitates splenic T cell egress and is linked to the cerebral recruitment of S1PR+ TH and TREG cells. Further insights by which means the S1P-S1PR-axis orchestrates neuronal positioning may offer new therapeutic perspectives after ischemic stroke.

scholarly journals In vivo network models identify sex differences in the spread of tau pathology across the brain

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Sepideh Shokouhi ◽  
Warren D. Taylor ◽  
Kimberly Albert ◽  
Hakmook Kang ◽  
Paul A. Newhouse ◽  
...  
Keyword(s):  
Sex Differences ◽  
Network Models ◽  
Tau Pathology ◽  
The Brain

Effect of pH and inhibitors on beta-amyloid fibril assembly

1996 ◽  
Vol 54 ◽  
pp. 752-753
Author(s):  
Beverly E. Maleeff ◽  
Timothy K. Hart ◽  
Stephen J. Wood ◽  
Ronald Wetzel
Keyword(s):  
Amyloid Fibril ◽  
Peptide Fragment ◽  
Hydrophobic Peptides ◽  
Amyloid Fibril Formation ◽  
Effects Of Ph ◽  
Severity Of The Disease ◽  
Kinetics Of ◽  
The Brain

Alzheimer's disease is characterized post-mortem in part by abnormal extracellular neuritic plaques found in brain tissue. There appears to be a correlation between the severity of Alzheimer's dementia in vivo and the number of plaques found in particular areas of the brain. These plaques are known to be the deposition sites of fibrils of the protein β-amyloid. It is thought that if the assembly of these plaques could be inhibited, the severity of the disease would be decreased. The peptide fragment Aβ, a precursor of the p-amyloid protein, has a 40 amino acid sequence, and has been shown to be toxic to neuronal cells in culture after an aging process of several days. This toxicity corresponds to the kinetics of in vitro amyloid fibril formation. In this study, we report the biochemical and ultrastructural effects of pH and the inhibitory agent hexadecyl-N-methylpiperidinium (HMP) bromide, one of a class of ionic micellar detergents known to be capable of solubilizing hydrophobic peptides, on the in vitro assembly of the peptide fragment Aβ.

Measuring the World

2018 ◽  
Author(s):  
Ann-Sophie Barwich
Keyword(s):  
Sensory Information ◽  
Network Models ◽  
Model System ◽  
Stimulus Input ◽  
Expectancy Effects ◽  
Neural Network Models ◽  
Perceptual Object ◽  
External Objects ◽  
The Common ◽  
The Brain

How much does stimulus input shape perception? The common-sense view is that our perceptions are representations of objects and their features and that the stimulus structures the perceptual object. The problem for this view concerns perceptual biases as responsible for distortions and the subjectivity of perceptual experience. These biases are increasingly studied as constitutive factors of brain processes in recent neuroscience. In neural network models the brain is said to cope with the plethora of sensory information by predicting stimulus regularities on the basis of previous experiences. Drawing on this development, this chapter analyses perceptions as processes. Looking at olfaction as a model system, it argues for the need to abandon a stimulus-centred perspective, where smells are thought of as stable percepts, computationally linked to external objects such as odorous molecules. Perception here is presented as a measure of changing signal ratios in an environment informed by expectancy effects from top-down processes.

scholarly journals Shared Blood Transcriptomic Signatures between Alzheimer’s Disease and Diabetes Mellitus

Biomedicines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 34
Author(s):  
Taesic Lee ◽  
Hyunju Lee
Keyword(s):  
Diabetes Mellitus ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Protein Interactions ◽  
Expression Patterns ◽  
Protein Protein Interactions ◽  
Hub Genes ◽  
Gene Modules ◽  
Gene Regulatory ◽  
The Brain

Alzheimer’s disease (AD) and diabetes mellitus (DM) are known to have a shared molecular mechanism. We aimed to identify shared blood transcriptomic signatures between AD and DM. Blood expression datasets for each disease were combined and a co-expression network was used to construct modules consisting of genes with similar expression patterns. For each module, a gene regulatory network based on gene expression and protein-protein interactions was established to identify hub genes. We selected one module, where COPS4, PSMA6, GTF2B, GTF2F2, and SSB were identified as dysregulated transcription factors that were common between AD and DM. These five genes were also differentially co-expressed in disease-related tissues, such as the brain in AD and the pancreas in DM. Our study identified gene modules that were dysregulated in both AD and DM blood samples, which may contribute to reveal common pathophysiology between two diseases.

scholarly journals Characterization of microglial transcriptomes in the brain and spinal cord of mice in early and late experimental autoimmune encephalomyelitis using a RiboTag strategy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shaona Acharjee ◽  
Paul M. K. Gordon ◽  
Benjamin H. Lee ◽  
Justin Read ◽  
Matthew L. Workentine ◽  
...  
Keyword(s):  
Gene Expression ◽  
Spinal Cord ◽  
Experimental Autoimmune Encephalomyelitis ◽  
Expression Patterns ◽  
Immune Functions ◽  
Autoimmune Encephalomyelitis ◽  
Transcriptional Changes ◽  
Brain And Spinal Cord ◽  
The Brain ◽  
Experimental Autoimmune

AbstractMicroglia play an important role in the pathogenesis of multiple sclerosis and the mouse model of MS, experimental autoimmune encephalomyelitis (EAE). To more fully understand the role of microglia in EAE we characterized microglial transcriptomes before the onset of motor symptoms (pre-onset) and during symptomatic EAE. We compared the transcriptome in brain, where behavioral changes are initiated, and spinal cord, where damage is revealed as motor and sensory deficits. We used a RiboTag strategy to characterize ribosome-bound mRNA only in microglia without incurring possible transcriptional changes after cell isolation. Brain and spinal cord samples clustered separately at both stages of EAE, indicating regional heterogeneity. Differences in gene expression were observed in the brain and spinal cord of pre-onset and symptomatic animals with most profound effects in the spinal cord of symptomatic animals. Canonical pathway analysis revealed changes in neuroinflammatory pathways, immune functions and enhanced cell division in both pre-onset and symptomatic brain and spinal cord. We also observed a continuum of many pathways at pre-onset stage that continue into the symptomatic stage of EAE. Our results provide additional evidence of regional and temporal heterogeneity in microglial gene expression patterns that may help in understanding mechanisms underlying various symptomology in MS.

scholarly journals Microglial Function and Regulation during Development, Homeostasis and Alzheimer’s Disease

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 957
Author(s):  
Brad T. Casali ◽  
Erin G. Reed-Geaghan
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Immune Cells ◽  
Expression Patterns ◽  
Brain Parenchyma ◽  
Primary Role ◽  
And Function ◽  
Inflammatory Milieu ◽  
The Brain ◽  
Homeostatic State

Microglia are the resident immune cells of the brain, deriving from yolk sac progenitors that populate the brain parenchyma during development. During development and homeostasis, microglia play critical roles in synaptogenesis and synaptic plasticity, in addition to their primary role as immune sentinels. In aging and neurodegenerative diseases generally, and Alzheimer’s disease (AD) specifically, microglial function is altered in ways that significantly diverge from their homeostatic state, inducing a more detrimental inflammatory environment. In this review, we discuss the receptors, signaling, regulation and gene expression patterns of microglia that mediate their phenotype and function contributing to the inflammatory milieu of the AD brain, as well as strategies that target microglia to ameliorate the onset, progression and symptoms of AD.

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