Anna King

Efficacy and dynamics of self-targeting CRISPR/Cas constructs for gene editing in the retina

Publisher: Cold Spring Harbor Laboratory

Date: 05-01-2018

DOI: 10.1101/243683

Abstract: Safe delivery of CRISPR/Cas endonucleases remains one of the major barriers to the widespread application of in vivo genome editing including the anticipatory treatment of monogenic retinal diseases. We previously reported the utility of adeno-associated virus (AAV)-mediated CRISPR/Cas genome editing in the retina however, with this type of viral delivery system, active endonucleases will remain in the retina for an extended period, making genotoxicity a significant consideration in clinical applications. To address this issue, we have designed a self-destructing “kamikaze” CRISPR/Cas system that disrupts the Cas enzyme itself following expression. Four guide RNAs (sgRNAs) were designed to target Streptococcus pyogenes Cas9 (SpCas9), after in situ validation, the selected sgRNAs were cloned into a dual AAV vector. One construct was used to deliver SpCas9 and the other delivered sgRNAs directed against SpCas9 and the target locus (yellow fluorescent protein, YFP), in the presence of mCherry. Both constructs were packaged into AAV2 vector and intravitreally administered in C57BL/6 and Thy1-YFP transgenic mice. After 8 weeks the expression of SpCas9, the efficacy of YFP gene disruption was quantified. A reduction of SpCas9 mRNA was found in retinas treated with AAV2-mediated-YFP/SpCas9 targeting CRISPR/Cas compared to those treated with YFP targeting CRISPR/Cas alone. We also show that AAV2-mediated delivery of YFP/SpCas9 targeting CRISPR/Cas significantly reduced the number of YFP fluorescent cells among mCherry-expressing cells (~85.5% reduction compared to LacZ/SpCas9 targeting CRISPR/Cas) in transfected retina of Thy1-YFP transgenic mice. In conclusion, our data suggest that a self-destructive “kamikaze” CRISPR/Cas system can be used as a robust tool for refined genome editing in the retina, without compromising on-target efficiency.

Lysosomal alterations and decreased electrophysiological activity in CLN3 disease patient-derived cortical neurons

Publisher: The Company of Biologists

Date: 12-2022

DOI: 10.1242/DMM.049651

Abstract: CLN3 disease is a lysosomal storage disorder associated with fatal neurodegeneration that is caused by mutations in CLN3, with most affected in iduals carrying at least one allele with a 966 bp deletion. Using CRISPR/Cas9, we corrected the 966 bp deletion mutation in human induced pluripotent stem cells (iPSCs) of a compound heterozygous patient (CLN3 Δ 966 bp and E295K). We differentiated these isogenic iPSCs, and iPSCs from an unrelated healthy control donor, to neurons and identified disease-related changes relating to protein synthesis, trafficking and degradation, and in neuronal activity, which were not apparent in CLN3-corrected or healthy control neurons. CLN3 neurons showed numerous membrane-bound vacuoles containing erse storage material and hyperglycosylation of the lysosomal LAMP1 protein. Proteomic analysis showed increase in lysosomal-related proteins and many ribosomal subunit proteins in CLN3 neurons, accompanied by downregulation of proteins related to axon guidance and endocytosis. CLN3 neurons also had lower electrophysical activity as recorded using microelectrode arrays. These data implicate inter-related pathways in protein homeostasis and neurite arborization as contributing to CLN3 disease, and which could be potential targets for therapy.

Microfluidic culture platform for studying neuronal response to mild to very mild axonal stretch injury

Publisher: AIP Publishing

Date: 07-2014

DOI: 10.1063/1.4891098

Abstract: A new model for studying localised axonal stretch injury is presented, using a microfluidic device to selectively culture axons on a thin, flexible poly (dimethylsiloxane) membrane which can be deflected upward to stretch the axons. A very mild (0.5% strain) or mild stretch injury (5% strain) was applied to primary cortical neurons after 7 days growth in vitro. The extent of distal degeneration was quantified using the degenerative index (DI, the ratio of fragmented axon area to total axon area) of axons fixed at 24 h and 72 h post injury (PI), and immunolabelled for the axon specific, microtubule associated protein-tau. At 24 h PI following very mild injuries (0.5%), the majority of the axons remained intact and healthy with no significant difference in DI when compared to the control, but at 72 h PI, the DI increased significantly (DI = 0.11 ± 0.03). Remarkably, dendritic beading in the somal compartment was observed at 24 h PI, indicative of dying back degeneration. When the injury level was increased (5% stretch, mild injury), microtubule fragmentation along the injured axons was observed, with a significant increase in DI at 24 h PI (DI = 0.17 ± 0.02) and 72 h PI (DI = 0.18 ± 0.01), relative to uninjured axons. The responses observed for both mild and very mild injuries are similar to those observed in the in vivo models of traumatic brain injury, suggesting that this model can be used to study neuronal trauma and will provide new insights into the cellular and molecular alterations characterizing the neuronal response to discrete axonal injury.

Island Study Linking Aging and Neurodegenerative Disease (ISLAND) Targeting Dementia Risk Reduction: Protocol for a Prospective Web-Based Cohort Study

Publisher: JMIR Publications Inc.

Date: 03-2022

DOI: 10.2196/34688

Abstract: Up to 40% of incident dementia is considered attributable to behavioral and lifestyle factors. Given the current lack of medical treatments and the projected increase in dementia prevalence, a focus on prevention through risk reduction is needed. We aim to increase dementia risk knowledge and promote changes in dementia risk behaviors at in idual and population levels. The Island Study Linking Aging and Neurodegenerative Disease (ISLAND) is a long-term prospective, web-based cohort study with nested interventions that will be conducted over a 10-year period. Target participants (n=10,000) reside in Tasmania and are aged 50 years or over. Survey data on knowledge, attitudes, and behaviors related to modifiable dementia risk factors will be collected annually. After each survey wave, participants will be provided with a personalized dementia risk profile containing guidelines for reducing risk across 9 behavioral and lifestyle domains and with opportunities to engage in educational and behavioral interventions targeting risk reduction. Survey data will be modeled longitudinally with intervention engagement indices, cognitive function indices, and blood-based biomarkers, to measure change in risk over time. In the initial 12 months (October 2019 to October 2020), 6410 participants have provided baseline data. The study is ongoing. Recruitment targets are feasible and efforts are ongoing to achieve a representative s le. Findings will inform future public health dementia risk reduction initiatives by showing whether, when, and how dementia risk can be lowered through educational and behavioral interventions, delivered in an uncontrolled real-world context. DERR1-10.2196/34688

Environmental novelty exacerbates stress hormones and Aβ pathology in an Alzheimer’s model

Publisher: Springer Science and Business Media LLC

Date: 05-06-2017

DOI: 10.1038/S41598-017-03016-0

Abstract: Cognitive stimulation has been proposed as a non-pharmacological intervention to be used in primary, secondary and tertiary prevention approaches for Alzheimer’s disease. A common familial Alzheimer’s disease transgenic model showed heightened levels of the stress hormone, corticosterone. When exposed to periodic enhanced cognitive stimulation, these animals demonstrated further heightened levels of corticosterone as well as increased Aβ pathology. Hence, Alzheimer’s disease may be associated with hypothalamic-pituitary-adrenal (HPA) axis dysfunction, causing stimulatory environments to become stress-inducing, leading to a glucocorticoid-pathology cycle contributing to further Aβ release and plaque formation. This finding suggests that stimulation-based interventions and local environments for people with Alzheimer’s disease need to be designed to minimise a stress response that may exacerbate brain pathology.

The impact of metallothionein-II on microglial response to tumor necrosis factor-alpha (TNFα) and downstream effects on neuronal regeneration

Publisher: Springer Science and Business Media LLC

Date: 22-02-2018

DOI: 10.1186/S12974-018-1070-3

O4‐06‐04: THE BDNF VAL66MET POLYMORPHISM INFLUENCES THE COGNITIVE BENEFITS OF AN EDUCATION INTERVENTION IN OLDER ADULTS

Publisher: Wiley

Date: 07-2018

DOI: 10.1016/J.JALZ.2018.06.2942

Iron is increased in the brains of ageing mice lacking the neurofilament light gene

Publisher: Public Library of Science (PLoS)

Date: 23-10-2019

DOI: 10.1371/JOURNAL.PONE.0224169

Cytoskeletal alterations differentiate presenilin-1 and sporadic Alzheimer’s disease

Publisher: Springer Science and Business Media LLC

Date: 18-11-2008

DOI: 10.1007/S00401-008-0458-Z

Abstract: Most cases of Alzheimer's disease (AD) are sporadic in nature, although rarer familial AD (FAD) cases have provided important insights into major pathological disease mechanisms. Mutations in the presenilin 1 gene (PS1) are responsible for the majority of FAD cases, causing an earlier age of onset and more rapid progression to end-stage disease than seen in sporadic AD. We have investigated the cytoskeletal alterations in neuritic AD pathology in a cohort of FAD cases in comparison to sporadic AD and pathologically aged cases. Tau-immunoreactive neurofibrillary tangle (NFT) loads were similar between PS1 FAD and sporadic AD cases. Similarly, plaque loads, both beta-amyloid (Abeta) and thioflavine S, in PS1 FAD and sporadic AD cases were not significantly different however, in pathologically aged cases, they were significantly lower than those in PS1 cases, but were not different from sporadic AD cases. The 'cotton wool' plaque characteristic of PS1 cases did not demonstrate a high density of dystrophic neurites compared to other Abeta plaque types, but did demonstrate a localised mass effect on the neuropil. Despite minimal differences in plaque and NFT loads, immunolabelling demonstrated clear phenotypic differences in the NFTs and dystrophic neurites in PS1 FAD cases. Presenilin-1 cases exhibited significantly (P < 0.05) more tau-positive NFTs that were immunolabelled by the antibody SMI312 (anti-phosphorylated NF protein and phosphorylated tau) than sporadic AD cases. Presenilin-1 cases also exhibited numerous ring-like NF-positive and elongated tau-labelled dystrophic neurites, whereas these dystrophic neurite types were only abundant at the very early (pathologically aged cases) or very late stages of sporadic AD progression, respectively. These differences in cytoskeletal pathology in PS1 cases suggest an accelerated rate of neuritic pathology development, potentially due to mutant PS1 influencing multiple pathogenic pathways.

Age Moderates the Effects of Traumatic Brain Injury on Beta-Amyloid Plaque Load in APP/PS1 Mice

Publisher: Mary Ann Liebert Inc

Date: 06-2019

DOI: 10.1089/NEU.2018.5982

Abstract: Traumatic brain injury (TBI) has been identified as a risk factor for Alzheimer's disease (AD). However, how such neural damage contributes to AD pathology remains unclear specifically, the relationship between the timing of a TBI relative to aging and the onset of AD pathology is not known. In this study, we have examined the effect of TBI on subsequent beta-amyloid (Aβ) deposition in APP/PS1 (APP

Sarm1 knockout modifies biomarkers of neurodegeneration and spinal cord circuitry but not disease progression in the mSOD1 mouse model of ALS

Publisher: Elsevier BV

Date: 10-2022

DOI: 10.1016/J.NBD.2022.105821

Abstract: The mechanisms underlying the loss of motor neuron axon integrity in amyotrophic lateral sclerosis (ALS) are unclear. SARM1 has been identified as a genetic risk variant in sporadic ALS, and the SARM1 protein is a key mediator of axon degeneration. To investigate the role of SARM1 in ALS-associated axon degeneration, we knocked out Sarm1 (Sarm1

Excitotoxin-induced caspase-3 activation and microtubule disintegration in axons is inhibited by taxol

Publisher: Springer Science and Business Media LLC

Date: 09-09-2013

DOI: 10.1186/2051-5960-1-59

ImageSURF: An ImageJ plugin for batch pixel-based image segmentation using random forests

Publisher: Ubiquity Press, Ltd.

Date: 06-11-2017

DOI: 10.5334/JORS.172

Level of distress in a recurrent low back pain population referred for physical therapy

Publisher: Ovid Technologies (Wolters Kluwer Health)

Date: 05-2003

DOI: 10.1097/00007632-200305010-00021

[P3–058]: THE ROLE OF MICROTUBULES IN EXCITOTOXIN‐INDUCED AXON DEGENERATION

Publisher: Wiley

Date: 07-2017

DOI: 10.1016/J.JALZ.2017.06.1268

Stainless Steel Pinholes for Fast Fabrication of High-Performance Microchip Electrophoresis Devices by CO₂ Laser Ablation

Publisher: American Chemical Society (ACS)

Date: 15-10-2013

DOI: 10.1021/AC402631G

Abstract: With the introduction of hobby laser engravers/cutters, the use of CO2 laser micromachining on poly(methyl methacrylate) (PMMA) has the potential for flexible, low cost, rapid prototyping of microfluidic devices. Unfortunately, the feature size created by most entry-level CO2 laser micromachining systems is too large to become a functional tool in analytical microfluidics. In this paper, we report a novel method to reduce the feature size of microchannels and the bulges formed at the rim of the channel during CO2 laser micromachining by passing the laser beam through a stainless steel pinhole. Without the pinhole, the channel width was typically 300 μm wide. However, when 50 or 35 μm diameter pinholes were used, channel widths of 60 and 25 μm, respectively, could be obtained. The height of the bulge deposited directly next to the channel was reduced to less than 0.8 μm with the pinhole during ablation. Separations of fluorescent dyes on devices ablated with and without the pinhole were compared. On devices fabricated with the pinhole, the number of theoretical plates/m was 2.2-fold higher compared to devices fabricated without the pinhole, and efficiencies comparable to embossed PMMA and laser ablated glass chips were obtained. A mass-produced commercial hobby laser (retailing at ∼$2500), when equipped with a $500 pinhole, represents a rapid and low-cost approach to the rapid fabrication of rigid plastic microchips including the narrow microchannels required for microchip electrophoresis.

Lysosomal alterations and decreased electrophysiological activity in CLN3 disease (966 bp deletion, E295K) patient-derived cortical neurons

Publisher: Cold Spring Harbor Laboratory

Date: 29-04-2022

DOI: 10.1101/2022.04.28.489465

Abstract: CLN3 disease is a lysosomal storage disorder associated with fatal neurodegeneration that is caused by mutations in CLN3 . Most in iduals with CLN3 disease carry at least one allele with a 966 bp deletion in CLN3 which results in the deletion of exons 7 and 8. There is a need for more physiologically relevant human cell-based CLN3 disease models to better understand the cellular changes during the disease process. Using CRISPR/Cas9, we corrected the 966 bp deletion mutation in human induced pluripotent stem cells (iPSCs) of a compound heterozygous patient ( CLN3 Δ 966 bp and E295K). The isogenic deletion-corrected and unedited CLN3 patient iPSCs were used for disease modeling. iPSC-derived neurons carrying this particular CLN3 mutation (CLN3 neurons) had lower functional activity as recorded using microelectrode arrays for most of the culture period. Proteomics analysis showed downregulation of proteins related to axon guidance and endocytosis at day in vitro (DIV) 14 and 42 in CLN3 neurons. This was accompanied by an increase in lysosomal-related proteins in CLN3 neurons. Western blot analysis revealed hyperglycosylation of the lysosomal marker, Lysosome Associated Membrane Protein 1 (LAMP1) in CLN3 neurons at DIV 14, 28 and 42, which was not apparent in control neurons. Ultrastructural analysis of CLN3 neurons showed numerous membrane-bound vacuoles containing erse types of storage material, ranging from curvilinear deposits, multilamellar structures to osmiophilic deposits. Our findings suggest alterations in lysosomal function and neurodevelopment involving axon guidance and synaptic transmission in CLN3-deficient neuronal derivatives, which could be potential targets for therapy.

Alpha-Synuclein protects neurons from apoptosis downstream of free-radical production through modulation of the MAPK signalling pathway

Publisher: Springer Science and Business Media LLC

Date: 31-08-2013

DOI: 10.1007/S12640-012-9352-5

Abstract: α-Synuclein is a pre-synaptic chaperone and its accumulation contributes to differential cell loss in Parkinson's disease. Cytoplasmic expression of α-synuclein can directly modulate apoptotic pathways and contribute to cell survival, whereas induced over-expression of the protein causes oxidative stress through mitochondrial and cytosolic free-radical production. This study aimed to clarify the contribution of endogenous α-synuclein to oxidative stress and its association with cell death. Primary cortical neurons were derived from α-synuclein knock-out (Snca-/-) and wild-type (C57BL/6 WT) mice and treated with in vitro models of oxidative-stress, complex I inhibition and excitotoxicity. Mitochondrial free radical production was determined in isolated mitochondria derived from each mouse strain. Snca-/- derived cortical cultures were more susceptible (P < 0.05) to oxidative-stress, but not excitotoxicity. This result was determined by significant increases in cell death (Propidium-Iodide staining) after 6 h treatment in Snca-/- (45 % ± 2.7 SEM), relative to WT (33 % ± 3.9 SEM) cultures. α-Synuclein also confers significant (P < 0.05) resistance to low-dose (5 nM) rotenone toxicity, with a twofold reduction in cell death in WT, compared with Snca-/- cortical neurons. The expression of α-synuclein had no effect on cortical glutathione levels, or the production of reactive oxygen intermediates in isolated mitochondria. These data indicate that endogenous levels of α-synuclein confer resistance to oxidative stress downstream of free radical production and scavenging. The current data suggest that α-synuclein prevents cytochrome c release and apoptosis through inhibition of the MAPK signalling pathway.

Late-life environmental enrichment preserves short-term memory and may attenuate microglia in male APP/PS1 mice

Publisher: Elsevier BV

Date: 06-2019

DOI: 10.1016/J.NEUROSCIENCE.2019.04.015

Abstract: Environmental enrichment (EE) has been consistently reported to enhance cognitive function in mouse models of neuropathology. Microglia, implicated in Alzheimer's disease pathology, may mediate this effect. The aim of the present study was to investigate the effect of EE on cognitive function and microglia in mouse models of aging and amyloidosis. Male wild-type (Wt) and APP/PS1 mice were randomly assigned to standard housing (SH) or EE from 12 to 18 months of age. Spatial memory testing was performed using the Y and Barnes maze. Immunohistochemical analysis of Aβ load, Iba1 and CD-68-labeled (phagocytic-type) microglia was examined between conditions. EE from 12 months of age was associated with improved short-term memory performance in APP/PS1 mice, despite no reductions to Aβ load. APP/PS1 mice in SH had significantly increased microglia occupying the neocortex and hippoc us (p = 0.02 p = 0.004, respectively) relative to Wt animals. Microglia labeling was not statistically different between EE-exposed APP/PS1 compared to Wt mice, indicating that EE may attenuate the increased microglial load in aging APP/PS1 mice. APP/PS1 mice from EE had significantly (p = 0.01) higher colocalization of Iba1 and CD-68 labeling, indicative of increased phagocytic microglia compared to mice from SH. The findings of the present study suggest that EE after substantial brain amyloidosis, has the potential to preserve domains of cognitive function, while having no effect on Aβ deposition. The current study demonstrates that EE may attenuate microglia in aging APP/PS1 mice, and may promote alterations in cellular phenotype.

Seeing Neurodegeneration in a New Light Using Genetically Encoded Fluorescent Biosensors and iPSCs

Publisher: MDPI AG

Date: 16-01-2023

DOI: 10.3390/IJMS24021766

Abstract: Neurodegenerative diseases present a progressive loss of neuronal structure and function, leading to cell death and irrecoverable brain atrophy. Most have disease-modifying therapies, in part because the mechanisms of neurodegeneration are yet to be defined, preventing the development of targeted therapies. To overcome this, there is a need for tools that enable a quantitative assessment of how cellular mechanisms and erse environmental conditions contribute to disease. One such tool is genetically encodable fluorescent biosensors (GEFBs), engineered constructs encoding proteins with novel functions capable of sensing spatiotemporal changes in specific pathways, enzyme functions, or metabolite levels. GEFB technology therefore presents a plethora of unique sensing capabilities that, when coupled with induced pluripotent stem cells (iPSCs), present a powerful tool for exploring disease mechanisms and identifying novel therapeutics. In this review, we discuss different GEFBs relevant to neurodegenerative disease and how they can be used with iPSCs to illuminate unresolved questions about causes and risks for neurodegenerative disease.

The potential roles of genetic factors in predicting ageing-related cognitive change and Alzheimer’s disease

Publisher: Elsevier BV

Date: 09-2021

DOI: 10.1016/J.ARR.2021.101402

A Novel In Vitro Primary Culture Model of the Lower Motor Neuron–Neuromuscular Junction Circuit

Publisher: Springer New York

Date: 2015

DOI: 10.1007/978-1-4939-2510-0_11

Combination treatment with leptin and pioglitazone in a mouse model of Alzheimer's disease

Publisher: Wiley

Date: 19-12-2016

DOI: 10.1016/J.TRCI.2016.11.002

Alterations in neurofilaments and the transformation of the cytoskeleton in axons may provide insight into the aberrant neuronal changes of Alzheimer’s disease

Publisher: Elsevier BV

Date: 09-2016

DOI: 10.1016/J.BRAINRESBULL.2016.07.012

Abstract: Neurofilaments are major protein constituents of the brain, but are particularly abundant in specific subpopulations of neurons and likely have a key role in the regulation of axonal calibre. Neurofilament proteins may also be involved in the transformation of the neuronal cytoskeleton leading to substantial tau pathology in axons damaged by Aβ, subsequently leading to neurofibrillary pathology in their cell bodies of origin. An understanding of neurofilamentous changes in axons and subsequent tau pathology may provide insight into how Aβ pathology may stimulate an aberrant plasticity-related response of damaged neurons, leading to the progressive and degenerative changes in the neuronal cytoskeleton that result in synapse loss and neuronal degeneration.

Accurate and Unbiased Quantitation of Amyloid-β Fluorescence Images Using ImageSURF

Publisher: Bentham Science Publishers Ltd.

Date: 04-02-2019

DOI: 10.2174/1567205016666181212152622

Abstract: Images of amyloid-β pathology characteristic of Alzheimer’s disease are difficult to consistently and accurately segment, due to diffuse deposit boundaries and imaging variations. We evaluated the performance of ImageSURF, our open-source ImageJ plugin, which considers a range of image derivatives to train image classifiers. We compared ImageSURF to standard image thresholding to assess its reproducibility, accuracy and generalizability when used on fluorescence images of amyloid pathology. ImageSURF segments amyloid-β images significantly more faithfully, and with significantly greater generalizability, than optimized thresholding. In addition to its superior performance in capturing human evaluations of pathology images, ImageSURF is able to segment image sets of any size in a consistent and unbiased manner, without requiring additional blinding, and can be retrospectively applied to existing images. The training process yields a classifier file which can be shared as supplemental data, allowing fully open methods and data, and enabling more direct comparisons between different studies.

Rab1-dependent ER-Golgi transport dysfunction is a common pathogenic mechanism in SOD1, TDP-43 and FUS-associated ALS.

Publisher: Springer Science and Business Media LLC

Date: 23-08-2015

DOI: 10.1007/S00401-015-1468-2

Abstract: Several erse proteins are linked genetically athologically to neurodegeneration in amyotrophic lateral sclerosis (ALS) including SOD1, TDP-43 and FUS. Using a variety of cellular and biochemical techniques, we demonstrate that ALS-associated mutant TDP-43, FUS and SOD1 inhibit protein transport between the endoplasmic reticulum (ER) and Golgi apparatus in neuronal cells. ER-Golgi transport was also inhibited in embryonic cortical and motor neurons obtained from a widely used animal model (SOD1(G93A) mice), validating this mechanism as an early event in disease. Each protein inhibited transport by distinct mechanisms, but each process was dependent on Rab1. Mutant TDP-43 and mutant FUS both inhibited the incorporation of secretory protein cargo into COPII vesicles as they bud from the ER, and inhibited transport from ER to the ER-Golgi intermediate (ERGIC) compartment. TDP-43 was detected on the cytoplasmic face of the ER membrane, whereas FUS was present within the ER, suggesting that transport is inhibited from the cytoplasm by mutant TDP-43, and from the ER by mutant FUS. In contrast, mutant SOD1 destabilised microtubules and inhibited transport from the ERGIC compartment to Golgi, but not from ER to ERGIC. Rab1 performs multiple roles in ER-Golgi transport, and over-expression of Rab1 restored ER-Golgi transport, and prevented ER stress, mSOD1 inclusion formation and induction of apoptosis, in cells expressing mutant TDP-43, FUS or SOD1. Rab1 also co-localised extensively with mutant TDP-43, FUS and SOD1 in neuronal cells, and Rab1 formed inclusions in motor neurons of spinal cords from sporadic ALS patients, which were positive for ubiquitinated TDP-43, implying that Rab1 is misfolded and dysfunctional in sporadic disease. These results demonstrate that ALS-mutant forms of TDP-43, FUS, and SOD1 all perturb protein transport in the early secretory pathway, between ER and Golgi compartments. These data also imply that restoring Rab1-mediated ER-Golgi transport is a novel therapeutic target in ALS.

Changes in TDP-43 expression in development, aging, and in the neurofilament light protein knockout mouse

Publisher: Elsevier BV

Date: 02-2015

DOI: 10.1016/J.NEUROBIOLAGING.2014.10.001

Abstract: The transactive response DNA-binding protein 43 (TDP-43) has been identified as a neurofilament light (NF-L) messenger RNA (mRNA)-binding protein. Abnormally increased levels of TDP-43 are detected in patients with amyotrophic lateral sclerosis and a downregulation of NF-L mRNA. However, links between NF-L and TDP-43 expressions are unclear. In this study, we investigated whether the deficiency of NF-L protein can result in alterations in TDP-43 localization or protein expression and whether this is altered with aging. There was a significant increase in TDP-43 protein levels in the cortex and lumbar spinal cord in 12-month-old NF-L knockout (NF-L KO) mice, compared with wild-type (WT) C57BL/6 mice. However, there was no difference in either the phosphorylation of TDP-43 between WT and NF-L KO mice or the abnormal mislocalization of TDP-43 to the cytoplasm in NF-L KO animals. Our findings suggest that NF-L protein or mRNA may negatively affect the expression of TDP-43 in the central nervous system. However, altered phosphorylation of TDP-43 may be more highly associated with aging than the levels of TDP-43 expression.

Regional differences in beta amyloid plaque deposition and variable response to midlife environmental enrichment in the cortex of APP/PS1 mice

Publisher: Wiley

Date: 05-11-2021

DOI: 10.1002/CNE.25060

Abstract: Environmentally enriched housing conditions can increase performance on cognitive tasks in APP/PS1 mice however, the potential effects of environmental enrichment (EE) on disease modification in terms of pathological change are inconclusive. We hypothesized that previous contrasting findings may be attributable to regional differences in susceptibility to amyloid beta (Aβ) plaque deposition in cortical regions that are functionally associated with EE. We characterized fibrillar plaque deposition in 6, 12, and 18-22 months old APP/PS1 mice in the prefrontal (PFC), somatosensory (SS2), and primary motor cortex (M1). We found a significant increase in plaque load between 6 and 12 months in all regions. In animals over 12 months, only the PFC region continued to significantly accumulate plaques. Additionally, 12 months old animals subjected to 6 months of EE showed improved spatial navigation and had significantly fewer plaques in M1 and SS2, but not in the PFC. These findings suggest that the PFC region is selectively susceptible to Aβ deposition and less responsive to the attenuating effects of EE. In contrast, M1 and SS2 regions plateau with respect to Aβ deposition by 12 months of age and are susceptible to amyloid pathology modification by midlife EE.

Coherence and cognition in the cortex: the fundamental role of parvalbumin, myelin, and the perineuronal net

Publisher: Springer Science and Business Media LLC

Date: 27-06-2021

DOI: 10.1007/S00429-021-02327-3

Abstract: The calcium binding protein parvalbumin is expressed in interneurons of two main morphologies, the basket and chandelier cells, which target perisomatic domains on principal cells and are extensively interconnected in laminar networks by synapses and gap junctions. Beyond its utility as a convenient cellular marker, parvalbumin is an unambiguous identifier of the key role that these interneurons play in the fundamental functions of the cortex. They provide a temporal framework for principal cell activity by propagating gamma oscillation, providing coherence for cortical information processing and the basis for timing-dependent plasticity processes. As these parvalbumin networks mature, they are physically and functionally stabilised by axonal myelination and development of the extracellular matrix structure termed the perineuronal net. This maturation correlates with the emergence of high-speed, highly energetic activity and provides a coherent foundation for the unique ability of the cortex to cross-correlate activity across sensory modes and internal representations.

TasTest: moving towards a digital screening test for pre-clinical Alzheimer’s disease

Publisher: Wiley

Date: 12-2021

DOI: 10.1002/ALZ.058732

Abstract: There is urgent need to develop population‐level digital biomarkers that can detect Alzheimer’s disease (AD) across the continuum, including the preclinical phase. This would allow risk stratification for specialist tests and early recruitment to clinical trials. Motor function declines in the preclinical phase but there has been little exploration of digital motor biomarkers. We have developed ‘TasTest’, an online test that assesses multiple cognitive domains, including movement. The aim of this study was to compare performance on TasTest with subtests of the Cambridge Neuropsychological Test Battery (CANTAB), a validated digital measure of cognitive decline, and determine how performance on the TasTest items varies with age in a large community s le of older adults. The TasTest items include measures of motor control (speed and coordination of keyboard tapping), processing speed (single and choice reaction time), attention and visual perception (identification of an animal in a distorted image), and visuospatial memory (identifying features from delayed recall of a complex figure). A total of 510 adults aged over 50 years (30% male mean 65.5 years SD 7.36), performed TasTest and CANTAB online assessments in their homes. We compared performance on TasTest items to performance on the Paired Associates Learning (PAL) task, which has been previously validated as predictive of accelerated cognitive decline (Barnett et al. 2015, Current Topics in Behavioral Neurosciences, vol 28, Springer, Cham). All TasTest items were significantly associated with PAL scores except the total number of correct responses on the reaction time tasks (Table 1). Several TasTest items had stronger correlations with age than the PAL, these included the keyboard tapping tasks, the number of correctly identified animals on the distorted image, and both simple and choice reaction times (Figure 1). Older people were able to readily complete TasTest tasks remotely from their homes, and performance on most items was significantly associated with scores on a previously validated test of cognition, and correlated with age. TasTest shows potential as a non‐invasive, scalable dementia screening tool.

Utility of Self-Destructing CRISPR/Cas Constructs for Targeted Gene Editing in the Retina

Publisher: Mary Ann Liebert Inc

Date: 11-2019

DOI: 10.1089/HUM.2019.021

Abstract: Safe delivery of CRISPR/Cas endonucleases remains one of the major barriers to the widespread application of

An online, public health framework supporting behaviour change to reduce dementia risk: interim results from the Island Study Linking Ageing and Neurodegenerative Disease

Publisher: Research Square Platform LLC

Date: 28-03-2023

DOI: 10.21203/RS.3.RS-2694489/V1

Abstract: Background : Behavioural and lifestyle factors contribute almost half of the risk of developing dementia. Addressing these factors might help prevent onset or slow disease progression. Given the rising prevalence and significant costs of dementia, a public health approach targeting these modifiable risk factors is warranted. Methods : The Island Study Linking Ageing and Neurodegenerative Disease (ISLAND) is a large, online, prospective public health research project. Over 13500 residents of Tasmania, Australia, aged 50+ years joined the project between 2019 and 2022, of whom 7270 consented to participate in research. Informed by health behaviour change models, participants’ knowledge, motivations, and behaviours related to modifiable dementia risk are measured at baseline and in annual surveys. Regression and mediation models were used to assess the effects of changes over time, and by exposure to two interventions: a personalised dementia risk profile (DRP) report provided after each survey wave, and the Preventing Dementia Massive Open Online Course (PDMOOC). Results : Data from 3038 participants (mean age 63.7 years, 71.6% female) were used in the reported analyses. The mean number of modifiable dementia risk factors reduced from 1.99 to 1.49 (out of 9) between joining the project and follow-up in 2022. This change was associated with time since baseline and the number of exposures to the DRP (b=-.06, p=.04) and was stronger for PDMOOC participants (b=-.14, p=.02). Markers of dementia risk literacy improved by DRP exposures (from b=.11 to b=.44, p .001) and by PDMOOC engagement (from b=.16 to b=.38, p .001). Six motivational factors changed by DRP exposure (from b=-.04 to b=.04, p’s .021), with stronger effect sizes observed for PDMOOC participants in four factors (from b=-.19 to b=.15, p’s .033). In PDMOOC participants, 13% of the observed behaviour change was mediated by changes in knowledge. Motivating factors – perceived susceptibility and self-efficacy – differentially affect the influence of higher knowledge on behaviour change. Conclusions : The ISLAND project offers a feasible public health framework for improving modifiable risk factors for dementia. The personalised DRP report and engagement with the PDMOOC work synergistically to increase dementia risk literacy and stimulate the intention and self-efficacy for changing risk behaviours.

Cortical Murine Neurons Lacking the Neurofilament Light Chain Protein Have an Attenuated Response to InjuryIn Vitro

Publisher: Mary Ann Liebert Inc

Date: 15-11-2013

DOI: 10.1089/NEU.2013.2850

Abstract: Neurofilaments (NFs) have been proposed to have a significant role in attempted axonal regeneration following a variety of forms of injury. The NF triplet proteins of the central nervous system are comprised of light (NF-L), medium (NF-M) and heavy (NF-H) chains and are part of the type IV intermediate filament family. We sought to define the role of NF-L in the neuronal response to trauma and regeneration by examining the effect of total absence of the NF-L protein on neuronal maturation and response to axotomy. This study utilized an in vitro model comprising relatively mature cortical murine neurons derived from either wild-type embryonic (E15) mice or mice with a genetic knockout of NF-L (NF-L KO). Whilst NF-L KO neurons developed to relative maturity at a comparable rate to wild-type control neurons, NF-L KO neurons demonstrated relatively increased expression of α-internexin and decreased expression of NF-M. Further, we demonstrate that α-internexin co-immunoprecipitates with the NF binding protein NDel1 in NFL-KO cortical neurons in vitro. Following localized axotomy, NF-L KO neurons demonstrated reduced amyloid precursor protein accumulation in damaged neurites as well as a significant reduction in the number of axons regenerating (4.79+/-0.58 sprouts) in comparison to control preparations (10.47+/-1.11 sprouts) (p<0.05). These studies indicate that NFs comprising NF-L have a dynamic role in the reactive and regenerative changes in axons following injury.

Alpha-synuclein is upregulated in neurones in response to chronic oxidative stress and is associated with neuroprotection

Publisher: Elsevier BV

Date: 06-2006

DOI: 10.1016/J.EXPNEUROL.2005.10.018

Abstract: Chronic oxidative stress has been linked to the neurodegenerative changes characteristic of Parkinson's disease, particularly alpha-synuclein accumulation and aggregation. However, it remains contentious whether these alpha-synuclein changes are cytotoxic or neuroprotective. The current study utilised long-term primary neural culture techniques with antioxidant free media to study the cellular response to chronic oxidative stress. Cells maintained in antioxidant free media were exquisitely more vulnerable to acute exposure to hydrogen peroxide, yet exposure of up to 10 days in antioxidant free media did not lead to morphological alterations in neurones or glia. However, a subpopulation of neurones demonstrated a significant increase in the level of alpha-synuclein expressed within the cell body and at synaptic sites. This subset of neurones was also more resistant to apoptotic changes following exposure to antioxidant free media relative to other neurones. These data indicate that increased alpha-synuclein content is associated with neuroprotection from relatively low levels of oxidative stress.

Identifying the primary site of pathogenesis in amyotrophic lateral sclerosis – vulnerability of lower motor neurons to proximal excitotoxicity

Publisher: The Company of Biologists

Date: 03-2015

DOI: 10.1242/DMM.018606

Abstract: There is a desperate need for targeted therapeutic interventions that slow the progression of amyotrophic lateral sclerosis (ALS). ALS is a disorder with heterogeneous onset, which then leads to common final pathways involving multiple neuronal compartments that span both the central and peripheral nervous system. It is believed that excitotoxic mechanisms might play an important role in motor neuron death in ALS. However, little is known about the mechanisms by which excitotoxicity might lead to the neuromuscular junction degeneration that characterizes ALS, or about the site at which this excitotoxic cascade is initiated. Using a novel compartmentalised model of site-specific excitotoxin exposure in lower motor neurons in vitro, we found that spinal motor neurons are vulnerable to somatodendritic, but not axonal, excitotoxin exposure. Thus, we developed a model of somatodendritic excitotoxicity in vivo using osmotic mini pumps in Thy-1-YFP mice. We demonstrated that in vivo cell body excitotoxin exposure leads to significant motor neuron death and neuromuscular junction (NMJ) retraction. Using confocal real-time live imaging of the gastrocnemius muscle, we found that NMJ remodelling preceded excitotoxin-induced NMJ degeneration. These findings suggest that excitotoxicity in the spinal cord of in iduals with ALS might result in a die-forward mechanism of motor neuron death from the cell body outward, leading to initial distal plasticity, followed by subsequent pathology and degeneration.

Axon pathology and repair

Publisher: Elsevier BV

Date: 10-2016

DOI: 10.1016/J.JCHEMNEU.2016.08.008

P4‐068: Mid‐Life Complex and Novel Environmental Enrichment Increase Corticosterone and Exacerbate AB Neuropathology in a Mouse Model of Alzheimer's Disease

Publisher: Wiley

Date: 07-2016

DOI: 10.1016/J.JALZ.2016.06.2158

Localization of glutamate receptors in developing cortical neurons in culture and relationship to susceptibility to excitotoxicity

Publisher: Wiley

Date: 2006

DOI: 10.1002/CNE.21053

Abstract: Overactivation of glutamate receptors leading to excitotoxicity has been implicated in the neurodegenerative alterations of a range of central nervous system (CNS) disorders. We have investigated the cell-type-specific changes in glutamate receptor localization in developing cortical neurons in culture, as well as the relationship between glutamate receptor subunit distribution with synapse formation and susceptibility to excitotoxicity. Glutamate receptor subunit clustering was present prior to the formation of synapses. However, different receptor types showed distinctive temporal patterns of subunit clustering, localization to spines, and apposition to presynaptic terminals. N-methyl-D-aspartate (NMDA) receptor subunit immunolabelling was present in puncta along dendrites prior to the formation of synapses, with relatively little localization to spines. Vulnerability to NMDA receptor-mediated excitotoxicity occurred before receptor subunits became localized in apposition to presynaptic terminals. Clustering of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors occurred concurrently with development of vulnerability to excitotoxicity and was related to localization of AMPA receptors at synapses and in spines. Different AMPA receptor subunits demonstrated cell-type-specific localization as well as distribution to spines, dendrites, and extrasynaptic subunit clusters. A subclass of neurons demonstrated substantial perineuronal synaptic innervation, and these neurons expressed relatively high levels of GluR1 and/or GluR4 at receptor puncta, indicating the presence of calcium-permeable AMPA receptors and suggesting alternative synaptic signalling mechanisms and vulnerability to excitotoxicity. These data demonstrate the relationship between glutamate receptor subunit expression and localization with synaptogenesis and development of neuronal susceptibility to excitotoxicity. These data also suggest that excitotoxicity can be mediated through extrasynaptic receptor subunit complexes along dendrites.

AAV-mediated CRISPR/Cas gene editing of retinal cellsin vivo

Publisher: Cold Spring Harbor Laboratory

Date: 09-02-2016

DOI: 10.1101/039156

Abstract: CRISPR/Cas has recently been adapted to enable efficient editing of the mammalian genome, opening novel avenues for therapeutic intervention of inherited diseases. In seeking to disrupt Yellow Fluorescent Protein (YFP) in a Thy1-YFP transgenic mouse, we assessed the feasibility of utilising the adeno-associated virus 2 (AAV2) to deliver CRISPR/Cas for gene modification of retinal cells in vivo . sgRNA plasmids were designed to target YFP and after in vitro validation, selected guides were cloned into a dual AAV system. One AAV2 construct was used to deliver SpCas9 and the other delivered sgRNA against YFP or LacZ (control) in the presence of mCherry. Five weeks after intravitreal injection, retinal function was determined using electroretinography and CRISPR/Casmediated gene modifications were quantified in retinal flat mounts. AAV2-mediated in vivo delivery of SpCas9 with sgRNA targeting YFP , significantly reduced the number of YFP fluorescent cells of the inner retina of our transgenic mouse model. Overall, we found an 84.0% (95% CI: 81.8-86.9) reduction of YFP-positive cells in YFP -sgRNA infected retinal cells compared to eyes treated with LacZ -sgRNA. Electroretinography profiling found no significant alteration in retinal function following AAV2-mediated delivery of CRISPR/Cas components compared to contralateral untreated eyes. Thy1-YFP transgenic mice were used as a rapid quantifiable means to assess the efficacy of CRISPR/Cas-based retinal gene modification in vivo . We demonstrate that genomic modification of cells in the adult retina can be readily achieved by viral mediated delivery of CRISPR/Cas.

Environmental enrichment as a preventative and therapeutic approach to Alzheimer's disease

Publisher: Elsevier

Date: 2020

DOI: 10.1016/B978-0-12-815854-8.00043-4

C9ORF72, implicated in amytrophic lateral sclerosis and frontotemporal dementia, regulates endosomal trafficking.

Publisher: Oxford University Press (OUP)

Date: 18-02-2014

DOI: 10.1093/HMG/DDU068

Isolated REM sleep behaviour disorder: current diagnostic procedures and emerging new technologies

Publisher: Springer Science and Business Media LLC

Date: 24-06-2022

DOI: 10.1007/S00415-022-11213-9

Abstract: Isolated REM sleep behaviour disorder (iRBD) is characterised by dream enactment behaviours, such as kicking and punching while asleep, and vivid/violent dreams. It is now acknowledged as a prodromal phase of neurodegenerative disease—approximately 80% of people with iRBD will develop dementia with Lewy Bodies, Parkinson’s disease or another degenerative brain disease within 10 years. It is important that neurologists and other clinicians understand how to make an early accurate diagnosis of iRBD so that affected people can have the opportunity to take part in clinical trials. However, making a diagnosis can be clinically challenging due to a variety of reasons, including delayed referral, symptom overlap with other disorders, and uncertainty about how to confirm a diagnosis. Several methods of assessment are available, such as clinical interview, screening questionnaires and video polysomnography or ‘sleep study’. This review aims to support clinical neurologists in assessing people who present with symptoms suggestive of iRBD. We describe the usefulness and limitations of each diagnostic method currently available in clinical practice, and present recent research on the utility of new wearable technologies to assist with iRBD diagnosis, which may offer a more practical assessment method for clinicians. This review highlights the importance of thorough clinical investigation when patients present with suspected iRBD and emphasises the need for easier access to diagnostic procedures for accurate and early diagnosis.

Effects of TDP-43 overexpression on neuron proteome and morphology in vitro

Publisher: Elsevier BV

Date: 07-2021

DOI: 10.1016/J.MCN.2021.103627

Glutamate induces rapid loss of axonal neurofilament proteins from cortical neurons in vitro

Publisher: Elsevier BV

Date: 06-2005

DOI: 10.1016/J.EXPNEUROL.2005.01.005

Abstract: One of the primary hallmarks of glutamate excitotoxicity is degradation of the neuronal cytoskeleton. Using a tissue culture approach, we have investigated the relationship between excitotoxicity and cytoskeletal degradation within axons, with particular reference to the axon specific neurofilament proteins. Neurofilaments were rapidly lost from axons over a 24-h period in response to excitotoxic insult (as observed by immunocytochemistry and western blotting), while other axonal cytoskeletal markers (such as betaIII-tubulin) remained intact. Treatment with kainic acid and NMDA, or complementary experiments using the pharmacological glutamate receptors blockers CNQX (kainate/AMPA receptor antagonist) and MK-801 (NMDA receptor antagonist), demonstrated that neurofilament degeneration was mediated primarily by NMDA receptor activity. This work suggests that excitotoxicity triggers a progressive pathway of cytoskeletal degeneration within axons, initially characterised by the loss of neurofilament proteins.

Modifiable risk factors for dementia, cognition, and plasma phosphorylated tau 181 in a large-scale cohort of Australian older adults

Publisher: Elsevier BV

Date: 11-2023

DOI: 10.1016/J.NEUROBIOLAGING.2023.06.018

Temporal changes in the microglial proteome of male and female mice after a diffuse brain injury using label-free quantitative proteomics

Publisher: Cold Spring Harbor Laboratory

Date: 02-05-2022

DOI: 10.1101/2022.05.01.490239

Abstract: Traumatic brain injury (TBI) triggers neuroinflammatory cascades mediated by microglia, which promotes tissue repair in the short-term. These cascades may exacerbate TBI-induced tissue damage and symptoms in the months to years post-injury. However, the progression of the microglial function across time post-injury and whether this differs between biological sexes is not well understood. In this study, we examined the microglial proteome in the days (3- and 7-days) to 1 month (28 days) after a midline fluid percussion injury (mFPI) in male and female mice using label-free quantitative proteomics. We identified a reduction in microglial proteins involved with clearance of neuronal debris via phagocytosis at 3- and 7-days post-injury. At 28 days post-injury pro-inflammatory proteins were decreased and anti-inflammatory proteins were increased in microglia. These results indicate a reduction in microglial clearance of neuronal debris in the days post-injury with a shift to anti-inflammatory function by 1 month. The changes in the microglial proteome that occurred across time post-injury did not differ between biological sexes. However, we did identify an increase in microglial proteins related to pro-inflammation as well as insulin and estrogen signalling in males compared with female mice that occurred with or without a brain injury. Although microglial response was similar between males and females up to 1 month following TBI, biological sex differences in the basal microglial proteome has implications for the efficacy of treatment strategies targeting the microglial response post-injury.

The metabolomics of alpha-synuclein (SNCA) gene deletion and mutation in mouse brain

Publisher: Springer Science and Business Media LLC

Date: 28-06-2013

DOI: 10.1007/S11306-013-0561-6

Association Between Components of Cognitive Reserve and Serum BDNF in Healthy Older Adults

Publisher: Frontiers Media SA

Date: 02-08-2021

DOI: 10.3389/FNAGI.2021.725914

Abstract: Background : The brain-derived neurotrophic factor (BDNF) protein has been shown to have a prominent role in neuron survival, growth, and function in experimental models, and the BDNF Val66Met polymorphism which regulates its expression has been linked to resilience toward the effects of aging on cognition. Cognitively stimulating activity is linked to both increased levels of BDNF in the brain, and protection against age-related cognitive decline. The aim of this study was to investigate the associations between serum BDNF levels, the BDNF Val66Met genotype, and components of cognitive reserve in early and mid-life, measured with the Lifetime of Experiences Questionnaire (LEQ). Methods : Serum BDNF levels were measured cross-sectionally in 156 participants from the Tasmanian Healthy Brain Project (THBP) cohort, a study examining the potential benefits of older adults engaging in a university-level education intervention. Multiple linear regression was used to estimate serum BDNF’s association with age, education, gender, BDNF Val66Met genotype, later-life university-level study, and cognitively stimulating activities measured by the LEQ. Results : Serum BDNF in older adults was associated with early life education and training, increasing 0.007 log(pg/ml) [95%CI 0.001, 0.012] per unit on the LEQ subscale. Conversely, education and training in mid-life were associated with a −0.007 log(pg/ml) [−0.012, −0.001] decrease per unit on the LEQ subscale. Serum BDNF decreased with age (−0.008 log(pg/ml) [−0.015, −0.001] per year), and male gender (−0.109 log(pg/ml) [−0.203, −0.015]), but mean differences between the BDNF Val66Met polymorphisms were not significant ( p = 0.066). All effect sizes were small, with mid-life education and training having the largest effect size ( η p 2 = 0.044). Conclusion : Education in both early and mid-life explained small but significant amounts of variance in serum BDNF levels, more than age or gender. These effects were opposed and independent, suggesting that education at different stages of life may be associated with different cognitive and neural demands. Education at different stages of life may be important covariates when estimating associations between other exposures and serum BDNF.

Axonal degeneration, distal collateral branching and neuromuscular junction architecture alterations occur prior to symptom onset in the SOD1G93A mouse model of amyotrophic lateral sclerosis

Publisher: Elsevier BV

Date: 10-2016

DOI: 10.1016/J.JCHEMNEU.2016.03.003

Abstract: Degeneration of the distal axon and neuromuscular junction (NMJ) is considered a key and early feature of the pathology that accompanies motor neuron loss in people with amyotrophic lateral sclerosis (ALS). The mutant SOD1(G93A) mouse replicates many features of the disease, however the sequence of events resulting in degeneration of the neuromuscular circuitry remains unknown. Furthermore, despite widespread degenerative neuronal pathology throughout the spinal cord in this model, hindlimb motor function is lost before forelimb function. We investigated axons and NMJs in the hindlimb (gastrocnemius) and forelimb (extensor) muscles in the high copy number mutant SOD1(G93A)xYFP (yellow fluorescent protein) mouse. We found that distal axonal and NMJ alterations were present prior to previously reported functional symptom onset in this strain. Indeed, increased branch complexity as well as colocalisation between pre- and post-synaptic markers indicated widespread early axonal and NMJ alterations in the hindlimb. Immunohistochemical analysis demonstrated that the colocalisation of the scaffolding proteins nestin, LRP-4, dystrophin and rapsyn were diminished before post-synaptic receptors in the gastrocnemius, and the degree of loss differed between proteins. Analysis of the forelimb muscle revealed axonal and NMJ degeneration at a late, post symptomatic stage, as well as novel differences in NMJ morphology, with reduced complexity. Furthermore, post-synaptic scaffolding proteins were preserved in the forelimb compared with the hindlimb. Analysis of protein levels indicated an increase in LRP-4, dystrophin and rapsyn in post symptomatic skeletal muscle that may suggest ongoing attempts at repair. This study indicates that axonal and NMJ degeneration in the SOD1 model of ALS is a complex and evolving sequence of events. We provide evidence that YFP can detect morphological and plastic alterations in the SOD1(G93A) mouse, and that the pre- and post-synaptic integrity of the NMJ plays an important role in the pathogenic mechanisms of ALS.

Microtubule‐dependent processes precede pathological calcium influx in excitotoxin‐induced axon degeneration

Publisher: Wiley

Date: 05-12-2019

DOI: 10.1111/JNC.14909

Abstract: Axon degeneration and axonal loss is a feature of neurodegenerative disease and injury and occurs via programmed pathways that are distinct from cell death pathways. While the pathways of axonal loss following axon severing are well described, less is known about axonal loss following other neurodegenerative insults. Here we use primary mouse cortical neuron cultures grown in compartmentalized chambers to investigate the role of calcium in the degeneration of axons that occurs following a somal insult by the excitotoxin kainic acid. Calcium influx has been implicated in both excitotoxicity and axon degeneration mechanisms, however the link between a somal insult and axonal calcium increase is unclear. Live imaging of axons demonstrated that pharmacologically preventing intracellular calcium increases through the endoplasmic reticulum or mitochondria significantly (p < 0.05) reduced axon degeneration. Live calcium-imaging with the Ca

P2‐048: DEVELOPMENTAL EXPRESSION OF FRONTOTEMPORAL DEMENTIA PROTEIN C9ORF72 IN VIVO AND IN VITRO

Publisher: Wiley

Date: 07-2014

DOI: 10.1016/J.JALZ.2014.05.721

Microglia directly associate with pericytes in the central nervous system

Publisher: Wiley

Date: 30-03-2023

DOI: 10.1002/GLIA.24371

Abstract: Cerebral blood flow (CBF) is important for the maintenance of brain function and its dysregulation has been implicated in Alzheimer's disease (AD). Microglia associations with capillaries suggest they may play a role in the regulation of CBF or the blood–brain‐barrier (BBB). We explored the relationship between microglia and pericytes, a vessel‐resident cell type that has a major role in the control of CBF and maintenance of the BBB, discovering a spatially distinct subset of microglia that closely associate with pericytes. We termed these pericyte‐associated microglia (PEM). PEM are present throughout the brain and spinal cord in NG2DsRed × CX 3 CR1 +/GFP mice, and in the human frontal cortex. Using in vivo two‐photon microscopy, we found microglia residing adjacent to pericytes at all levels of the capillary tree and found they can maintain their position for at least 28 days. PEM can associate with pericytes lacking astroglial endfeet coverage and capillary vessel width is increased beneath pericytes with or without an associated PEM, but capillary width decreases if a pericyte loses a PEM. Deletion of the microglia fractalkine receptor (CX 3 CR1) did not disrupt the association between pericytes and PEM. Finally, we found the proportion of microglia that are PEM declines in the superior frontal gyrus in AD. In summary, we identify microglia that specifically associate with pericytes and find these are reduced in number in AD, which may be a novel mechanism contributing to vascular dysfunction in neurodegenerative diseases.

Focal Damage to the Adult Rat Neocortex Induces Wound Healing Accompanied by Axonal Sprouting and Dendritic Structural Plasticity

Publisher: Oxford University Press (OUP)

Date: 28-05-2010

DOI: 10.1093/CERCOR/BHQ091

Abstract: Accumulating evidence indicates that damage to the adult mammalian brain evokes an array of adaptive cellular responses and may retain a capacity for structural plasticity. We have investigated the cellular and architectural alterations following focal experimental brain injury, as well as the specific capacity for structural remodeling of neuronal processes in a subset of cortical interneurons. Focal acute injury was induced by transient insertion of a needle into the neocortex of anesthetized adult male Hooded-Wistar rats and thy1 green fluorescent protein (GFP) mice. Immunohistochemical, electron microscopy, and bromodeoxyuridine cell proliferation studies demonstrated an active and evolving response of the brain to injury, indicating astrocytic but not neuronal proliferation. Immunolabeling for the neuron-specific markers phosphorylated neurofilaments, α-internexin and calretinin at 7 days post injury (DPI) indicated phosphorylated neurofilaments and α-internexin but not calretinin immunopositive axonal sprouts within the injury site. However, quantitative studies indicated a significant realignment of horizontally projecting dendrites of calretinin-labeled interneurons at 14 DPI. This remodeling was specific to calretinin immunopositive interneurons and did not occur in a subpopulation of pyramidal neurons expressing GFP in the injured mouse cortex. These data show that subclasses of cortical interneurons are capable of adaptive structural remodeling.

Retinal ganglion cell axons regenerate in the presence of intact sensory fibres

Publisher: Ovid Technologies (Wolters Kluwer Health)

Date: 02-2006

DOI: 10.1097/01.WNR.0000195668.07467.A8

Abstract: A novel allograft paradigm was used to test whether adult mammalian central axons regenerate within a peripheral nerve environment containing intact sensory axons. Retinal ganglion cell axon regeneration was compared following anastomosis of dorsal root ganglia grafts or conventional peripheral nerve grafts to the adult rat optic nerve. Dorsal root ganglia grafts comprised intact sensory and degenerate motor axons, whereas conventional grafts comprised both degenerating sensory and motor axons. Retinal ganglion cell axons were traced after 2 months. Dorsal root ganglia survived with their axons persisting throughout the graft. Comparable numbers of retinal ganglion cells regenerated axons into both dorsal root ganglia (1053+/-223) and conventional grafts (1323+/-881 P>0.05). The results indicate that an intact sensory environment supports central axon regeneration.

The role of Alzheimer’s disease polygenic risk scores in changes of cognitive function in older adults: A longitudinal cohort study

Publisher: Wiley

Date: 12-2020

DOI: 10.1002/ALZ.037853

Excitotoxicity and Axon Degeneration

Publisher: Springer New York

Date: 2014

DOI: 10.1007/978-1-4614-5836-4_145

Axonal shearing in mature cortical neurons induces attempted regeneration and the reestablishment of neurite polarity

Publisher: Elsevier BV

Date: 11-2009

DOI: 10.1016/J.BRAINRES.2009.08.059

Abstract: While functional recovery after injury is limited, it has become evident that the mature central nervous system does retain some ability to regenerate. This study investigated the intrinsic capacity of relatively mature cortical neurons (21 days in vitro) to respond to axonal loss. Neurons, growing as clusters on poly-L-lysine, were completely sheared of axons through chemical and mechanical disruption and transferred to either an intact astrocyte monolayer or a substrate of poly-L-lysine. Injured neurons exhibited a regenerative sprouting response that was independent of neuronal cell ision or neural progenitors, as demonstrated by negative bromodeoxyuridine (BrdU) and the neuronal precursor intermediate filament nestin, labeling. At 24 h after injury, neurons had extended appropriately polarized neurites, demonstrated by compartmentalized microtubule-associated proteins MAP2 and tau immunolabeling. Newly sprouting axons were tipped by growth cones however, growth cones on the tips of sprouting axons (mean area, 26.32 +/- 2.20 microm) were significantly (p<0.05) smaller than their developmental counterparts (mean area, 48.64 +/- 5.9 microm), independent of substrate. Furthermore, live imaging indicated that regenerating neurons exhibited distinct axonal dynamics, with a significant (p<0.05) reduction (70%) in pausing, considered vital for interstitial branching and pathfinding, relative to developmental growth cones. This study indicates that mature cultured cortical pyramidal and interneurons have the intrinsic potential to survive, extend processes, and reestablish neurite polarity following significant physical damage. These results may aid in defining the cellular basis of neuronal structural plasticity and defining the role of astrocyte reactivity in the response to trauma.

Calretinin and Neuropeptide Y interneurons are differentially altered in the motor cortex of the SOD1G93A mouse model of ALS

Publisher: Springer Science and Business Media LLC

Date: 15-03-2017

DOI: 10.1038/SREP44461

Abstract: Increasing evidence indicates an excitatory/inhibitory imbalance may have a critical role in the pathogenesis of amyotrophic lateral sclerosis (ALS). Impaired inhibitory circuitry is consistently reported in the motor cortex of both familial and sporadic patients, closely associated with cortical hyperexcitability and ALS onset. Inhibitory network dysfunction is presumably mediated by intra-cortical inhibitory interneurons, however, the exact cell types responsible are yet to be identified. In this study we demonstrate dynamic changes in the number of calretinin- (CR) and neuropeptide Y-expressing (NPY) interneurons in the motor cortex of the familial hSOD1 G93A ALS mouse model, suggesting their potential involvement in motor neuron circuitry defects. We show that the density of NPY-populations is significantly decreased by ~17% at symptom onset (8 weeks), and by end-stage disease (20 weeks) is significantly increased by ~30%. Conversely, the density of CR-populations is progressively reduced during later symptomatic stages (~31%) to end-stage (~36%), while CR-expressing interneurons also show alteration of neurite branching patterns at symptom onset. We conclude that a differential capacity for interneurons exists in the ALS motor cortex, which may not be a static phenomenon, but involves early dynamic changes throughout disease, implicating specific inhibitory circuitry.

If Human Brain Organoids Are the Answer to Understanding Dementia, What Are the Questions?

Publisher: SAGE Publications

Date: 13-04-2020

DOI: 10.1177/1073858420912404

Abstract: Because our beliefs regarding our in iduality, autonomy, and personhood are intimately bound up with our brains, there is a public fascination with cerebral organoids, the “mini-brain,” the “brain in a dish”. At the same time, the ethical issues around organoids are only now being explored. What are the prospects of using human cerebral organoids to better understand, treat, or prevent dementia? Will human organoids represent an improvement on the current, less-than-satisfactory, animal models? When considering these questions, two major issues arise. One is the general challenge associated with using any stem cell–generated preparation for in vitro modelling (challenges lified when using organoids compared with simpler cell culture systems). The other relates to complexities associated with defining and understanding what we mean by the term “dementia.” We discuss 10 puzzles, issues, and stumbling blocks to watch for in the quest to model “dementia in a dish.”

Microfluidic primary culture model of the lower motor neuron–neuromuscular junction circuit

Publisher: Elsevier BV

Date: 09-2013

DOI: 10.1016/J.JNEUMETH.2013.06.002

Abstract: Modelling the complex process of neuromuscular signalling is key to understanding not only normal circuit function but also importantly the mechanisms underpinning a range of degenerative diseases. We describe a novel in vitro model of the lower motor neuron-neuromuscular junction circuit, incorporating primary spinal motor neurons, supporting glia and skeletal muscle. This culture model is designed to spatially mimic the unique anatomical and cellular interactions of this circuit in compartmented microfluidic devices, such that the glial cells are located with motor neuron cell bodies in the cell body chamber and motor neuron axons extend to a distal chamber containing skeletal muscle cells whilst simultaneously allowing targeted intervention. This model is suitable for use in conjunction with a range of downstream experimental approaches and could also be modified to utilise other cellular sources including appropriate immortal cell lines, cells derived from transgenic models of disease and also patient derived stem cells.

Chronic Pain in Multiple Sites and Dementia: A Vicious Cycle?

Publisher: SERDI

Date: 2023

DOI: 10.14283/JPAD.2023.120

Connectivity of Pathology: The Olfactory System as a Model for Network-Driven Mechanisms of Alzheimer’s Disease Pathogenesis

Publisher: Frontiers Media SA

Date: 15-12-2015

DOI: 10.3389/FNAGI.2015.00234

Neurofilament light gene deletion exacerbates amyloid, dystrophic neurite, and synaptic pathology in the APP/PS1 transgenic model of Alzheimer's disease

Publisher: Elsevier BV

Date: 10-2015

DOI: 10.1016/J.NEUROBIOLAGING.2015.07.003

Abstract: Alzheimer's disease (AD) is a progressive neurodegenerative disease associated with the loss of cognitive function. Neurofilament (NF) triplet proteins, the major structural (intermediate filament) proteins of neurons, are expressed in a subset of pyramidal cells that show a high degree of vulnerability to degeneration in AD. Alterations in the NF triplet proteins in amyloid-beta (Aβ) plaque-associated dystrophic neurites (DNs) represent the first cytoskeletal aberration to occur in the neocortex in the earliest stages of AD. We generated transgenic APP/PS1 (APPswe/PSEN1dE9) mice on the neurofilament light knockout (NFL KO) background to explore the role of NFL deletion in the context of DN formation, synaptic changes, and other neuropathologic features. Our analysis demonstrated that NFL deficiency significantly increased neocortical DN pathology, Aβ deposition, synapse vulnerability, and microgliosis in APP/PS1 mice. Thus, NFs may have a role in protecting neurites from dystrophy and in regulating cellular pathways related to the generation of Aβ plaques.

Age is no barrier: predictors of academic success in older learners

Publisher: Springer Science and Business Media LLC

Date: 15-11-2017

DOI: 10.1038/S41539-017-0014-5

Abstract: Although predictors of academic success have been identified in young adults, such predictors are unlikely to translate directly to an older student population, where such information is scarce. The current study aimed to examine cognitive, psychosocial, lifetime, and genetic predictors of university-level academic performance in older adults (50–79 years old). Participants were mostly female (71%) and had a greater than high school education level ( M = 14.06 years, SD = 2.76), on average. Two multiple linear regression analyses were conducted. The first examined all potential predictors of grade point average (GPA) in the subset of participants who had volunteered s les for genetic analysis ( N = 181). Significant predictors of GPA were then re-examined in a second multiple linear regression using the full s le ( N = 329). Our data show that the cognitive domains of episodic memory and language processing, in conjunction with midlife engagement in cognitively stimulating activities, have a role in predicting academic performance as measured by GPA in the first year of study. In contrast, it was determined that age, IQ, gender, working memory, psychosocial factors, and common brain gene polymorphisms linked to brain function, plasticity and degeneration ( APOE , BDNF , COMT , KIBRA, SERT ) did not influence academic performance. These findings demonstrate that ageing does not impede academic achievement, and that discrete cognitive skills as well as lifetime engagement in cognitively stimulating activities can promote academic success in older adults.

Microfluidic Device for Studying Traumatic Brain Injury

Publisher: Springer New York

Date: 2017

DOI: 10.1007/978-1-4939-7024-7_10

Cortical axon sub-population maintains density, but not turnover, of en passant boutons in the aged APP/PS1 amyloidosis model

Publisher: Elsevier BV

Date: 07-2022

DOI: 10.1016/J.NEUROBIOLAGING.2022.03.007

Abstract: Synaptic dysfunction is one of the key mechanisms associated with cognitive deficits observed in Alzheimer's disease (AD), yet little is known about the presynaptic axonal boutons in AD. Focusing on cortical en passant boutons (EPBs) along axons located in the motor, sensory and prefrontal regions of the cerebral cortex in the APP/PS1 mouse model of AD, we investigated structural properties of EPBs over the lifespan and in response to a midlife environmental enrichment (EE) intervention. At 3, 12, and 18-22 months and following 6 months of midlife EE, we found that EPBs showed remarkable resilience in preserving overall synaptic output, as evidenced by the maintained density of EPBs along the axon shaft across all experimental conditions. Using cranial window imaging to monitor synaptic changes in real time, we report that despite maintaining a stable synaptic density, the dynamic fraction (gains and losses) of EPBs was significantlyreduced at 10-13 months of age in APP/PS1 axons compared to age matched controls.

Defining the earliest pathological changes of Alzheimer's disease

Publisher: Bentham Science Publishers Ltd.

Date: 12-02-2016

DOI: 10.2174/1567205013666151218150322

Abstract: The prospects for effectively treating well-established dementia, such as Alzheimer's disease (AD), are slim, due to the destruction of key brain pathways that underlie higher cognitive function. There has been a substantial shift in the field towards detecting conditions such as AD in their earliest stages, which would allow preventative or therapeutic approaches to substantially reduce risk and/or slow the progression of disease. AD is characterized by hallmark pathological changes such as extracellular Aβ plaques and intracellular neurofibrillary pathology, which selectively affect specific subclasses of neurons and brain circuits. Current evidence indicates that Aβ plaques begin to form many years before overt dementia, a gradual and progressive pathology which offers a potential target for early intervention. Early Aβ changes in the brain result in localized damage to dendrites, axonal processes and synapses, to which excitatory synapses and the processes of projection neurons are highly vulnerable. Aβ pathology is replicated in a range of transgenic models overexpressing mutant human familial AD genes (e.g. APP and presenilin 1). Studying the development of aberrant regenerative and degenerative changes in neuritic processes associated with Aβ plaques may represent the best opportunity to understand the relationship between the pathological hallmarks of AD and neuronal damage, and to develop early interventions to prevent, slow down or mitigate against Aβ pathology and/or the neuronal alterations that leads to cognitive impairment.

Excitotoxicity in ALS: Overstimulation, or overreaction?

Publisher: Elsevier BV

Date: 2016

DOI: 10.1016/J.EXPNEUROL.2015.09.019

Abstract: Amyotrophic lateral sclerosis (ALS) is an adult onset neurodegenerative disease that results in motor dysfunction and death, generally from respiratory failure. 90% of ALS cases are sporadic with no known cause. Familial cases have been linked with mutations in several disparate classes of genes, including those involved in DNA/RNA metabolism, protein misfolding, oxidative stress and the cytoskeleton, leading to the proposition that ALS could be a multi-factorial disease. However, alterations in excitability have been reported in all types of ALS cases, and may be a common disease mechanism predisposing neurons to degeneration. Excitotoxicity has long been suspected as a mediator in the disease process, and may arise from changes in synaptic inputs, or alterations in the excitability of the neurons being stimulated. Although the glutamatergic system is widely recognised as a therapeutic avenue with the potential to extend lifespan and delay disease onset, the causes of altered excitability in ALS are currently unclear and warrant further investigation. This article reviews current evidence of alterations to excitatory and inhibitory signalling in the cortex and spinal cord, and in the intrinsic excitability of motor neurons, in ALS.

The TAS Test project: a prospective longitudinal validation of new online motor-cognitive tests to detect preclinical Alzheimer’s disease and estimate 5-year risks of cognitive decline and dementia

Publisher: Springer Science and Business Media LLC

Date: 18-07-2022

DOI: 10.1186/S12883-022-02772-5

Abstract: The worldwide prevalence of dementia is rapidly rising. Alzheimer’s disease (AD), accounts for 70% of cases and has a 10–20-year preclinical period, when brain pathology covertly progresses before cognitive symptoms appear. The 2020 Lancet Commission estimates that 40% of dementia cases could be prevented by modifying lifestyle/medical risk factors. To optimise dementia prevention effectiveness, there is urgent need to identify in iduals with preclinical AD for targeted risk reduction. Current preclinical AD tests are too invasive, specialist or costly for population-level assessments. We have developed a new online test, TAS Test, that assesses a range of motor-cognitive functions and has capacity to be delivered at significant scale. TAS Test combines two innovations: using hand movement analysis to detect preclinical AD, and computer-human interface technologies to enable robust ‘self-testing’ data collection. The aims are to validate TAS Test to [1] identify preclinical AD, and [2] predict risk of cognitive decline and AD dementia. Aim 1 will be addressed through a cross-sectional study of 500 cognitively healthy older adults, who will complete TAS Test items comprising measures of motor control, processing speed, attention, visuospatial ability, memory and language. TAS Test measures will be compared to a blood-based AD biomarker, phosphorylated tau 181 (p-tau181). Aim 2 will be addressed through a 5-year prospective cohort study of 10,000 older adults. Participants will complete TAS Test annually and subtests of the Cambridge Neuropsychological Test Battery (CANTAB) biennially. 300 participants will undergo in-person clinical assessments. We will use machine learning of motor-cognitive performance on TAS Test to develop an algorithm that classifies preclinical AD risk (p-tau181-defined) and determine the precision to prospectively estimate 5-year risks of cognitive decline and AD. This study will establish the precision of TAS Test to identify preclinical AD and estimate risk of cognitive decline and AD. If accurate, TAS Test will provide a low-cost, accessible enrichment strategy to pre-screen in iduals for their likelihood of AD pathology prior to more expensive tests such as blood or imaging biomarkers. This would have wide applications in public health initiatives and clinical trials. ClinicalTrials.gov Identifier: NCT05194787 , 18 January 2022. Retrospectively registered.

Axonal injury in brain trauma: influence of the neurofilament cytoskeleton on pathology

Publisher: Elsevier BV

Date: 2015

DOI: 10.1097/01.PAT.0000461528.61449.3C

Pathological Links between Traumatic Brain Injury and Dementia: Australian Pre-Clinical Research

Publisher: Mary Ann Liebert Inc

Date: 03-2020

DOI: 10.1089/NEU.2019.6906

ALS-associated mutant FUS inhibits macroautophagy which is restored by overexpression of Rab1

Publisher: Springer Science and Business Media LLC

Date: 14-09-2015

DOI: 10.1038/CDDISCOVERY.2015.30

Abstract: Amyotrophic lateral sclerosis (ALS) is characterised by the formation of intracellular misfolded protein inclusions that form in motor neurons. Autophagy is the major degradation pathway for aggregate-prone proteins within lysosomes. Autophagy begins by the production of the omegasome, forming the autophagosome membrane, which then fuses with the lysosome. Mutations in fused in sarcoma (FUS) cause 5% of familial ALS cases and FUS-positive inclusions are also formed in sporadic ALS tissues. In this study, we demonstrate that the expression of ALS-associated mutant FUS impairs autophagy in neuronal cells. In mutant FUS-expressing neuronal cells, accumulation of ubiquitinated proteins and autophagy substrates p62 and NBR1 was detected, and formation of both the omegasome and autophagosome was inhibited in these cells. However, overexpression of Rab1 rescued these defects, suggesting that Rab1 is protective in ALS. The number of LC3-positive vesicles was also increased in motor neurons from the spinal cord of an ALS patient carrying a FUS (R521C) mutation compared with a control patient, providing additional evidence that autophagy is dysregulated in mutant FUS-associated ALS. This study provides further understanding of the intricate autophagy system and neurodegeneration in ALS.

Excitotoxicity mediated by non‐NMDA receptors causes distal axonopathy in long‐term cultured spinal motor neurons

Publisher: Wiley

Date: 10-2007

DOI: 10.1111/J.1460-9568.2007.05845.X

Abstract: Excitotoxicity has been implicated as a potential cause of neuronal degeneration in amyotrophic lateral sclerosis (ALS). It has not been clear how excitotoxic injury leads to the hallmark pathological changes of ALS, such as the abnormal accumulation of filamentous proteins in axons. We have investigated the effects of overactivation of excitatory receptors in rodent neurons maintained in long-term culture. Excitotoxicity, mediated principally via non-N-methyl-D-aspartate (NMDA) receptors, caused axonal swelling and accumulation of cytoskeletal proteins in the distal segments of the axons of cultured spinal, but not cortical, neurons. Axonopathy only occurred in spinal neurons maintained for 3 weeks in vitro, indicating that susceptibility to axonal pathology may be related to relative maturity of the neuron. Excitotoxic axonopathy was associated with the aberrant colocalization of phosphorylated and dephosphorylated neurofilament proteins, indicating that disruption to the regulation of phosphorylation of neurofilaments may lead to their abnormal accumulation. These data provide a strong link between excitotoxicity and the selective pattern of axonopathy of lower motor neurons that underlies neuronal dysfunction in ALS.

Axonopathy and cytoskeletal disruption in degenerative diseases of the central nervous system

Publisher: Elsevier BV

Date: 10-2009

DOI: 10.1016/J.BRAINRESBULL.2009.08.004

Abstract: There has been growing interest in the axon as the initial focus of pathological change in a number of neurodegenerative diseases of the central nervous system. This review concentrates on three major neurodegenerative conditions--amyotrophic lateral sclerosis, multiple sclerosis and Alzheimer's disease--with emphasis on key cellular changes that may underlie early axonal dysfunction and pathology and, potentially, the degeneration of neurons. In particular, this review will address recent data that indicate that the main pathological stimuli for these conditions, though often not definitively determined, result in an initial perturbation of the axon and its cytoskeleton, which then results in slow neuronal degeneration and loss of connectivity. The identification of a degenerative process initiated in the axon may provide new therapeutic targets for early intervention to inhibit the grim outcomes related to the progression of these diseases.

C9ORF72 expression and cellular localization over mouse development

Publisher: Springer Science and Business Media LLC

Date: 25-09-2015

DOI: 10.1186/S40478-015-0238-7

Neuron–glia interactions underlie ALS-like axonal cytoskeletal pathology

Publisher: Elsevier BV

Date: 03-2011

DOI: 10.1016/J.NEUROBIOLAGING.2009.04.004

Abstract: Amyotrophic lateral sclerosis (ALS) is a devastating disorder involving loss of movement due to degeneration of motor neurons. Studies suggest that in ALS axonal dysfunction precedes the death of motor neurons. Pathologically, ALS is characterized by neurofilamentous swellings (spheroids) within the axons of motor neurons. However, the causes of this axonopathy and possible resulting axonal dysfunction are not known. Using a novel model of cultured mouse motor neurons, we have determined that these neurons are susceptible to proximal axonopathy, which is related to the glial environment. This axonopathy showed remarkable similarity, both morphologically and neurochemically, to spheroids that develop over months in SOD1(G93A) transgenic mice. Focal ubiquitination, as well as perturbations of neurofilaments and microtubules, occurred in the axonal spheroid-like swellings in vitro, and visualization of mitochondrial dynamics demonstrated that axonopathy resulted in impaired axonal transport. These data provide strong evidence for the involvement of non-neuronal cells in axonal dysfunction in ALS. This cell culture model may be of benefit for the development of therapeutic interventions directed at axonal preservation.

The HDAC6 Inhibitor Trichostatin A Acetylates Microtubules and Protects Axons From Excitotoxin-Induced Degeneration in a Compartmented Culture Model

Publisher: Frontiers Media SA

Date: 29-11-2018

DOI: 10.3389/FNINS.2018.00872

Erratum: C9ORF72 expression and cellular localization over mouse development (vol 3, 59, 2015)

Publisher: Springer Science and Business Media LLC

Date: 04-01-2016

DOI: 10.1186/S40478-015-0253-8

Mild and repetitive very mild axonal stretch injury triggers cystoskeletal mislocalization and growth cone collapse

Publisher: Public Library of Science (PLoS)

Date: 04-05-2017

DOI: 10.1371/JOURNAL.PONE.0176997

The effect of focal brain injury on beta-amyloid plaque deposition, inflammation and synapses in the APP/PS1 mouse model of Alzheimer's disease

Publisher: Elsevier BV

Date: 05-2015

DOI: 10.1016/J.EXPNEUROL.2015.02.034

Abstract: Traumatic brain injury is a risk factor for Alzheimer's disease (AD), however the effect of such neural damage on the onset and progression of beta-amyloid (Aβ) plaque pathology is not well understood. This study utilized an in vivo model of focal brain injury to examine how localized damage may acutely affect the onset and progression of Aβ plaque deposition as well as inflammatory and synaptic changes, in the APP/PS1 (APPSWE, PSEN1dE9) transgenic model of AD relative to wild-type (Wt) mice. Acute focal brain injury in 3- and 9-month-old APP/PS1 and Wt mice was induced by insertion of a needle into the somatosensory neocortex, as compared to sham surgery, and examined at 24h and 7d post-injury (PI). Focal brain injury did not induce thioflavine-S stained or (pan-Aβ antibody) MOAB-2-labeled plaques at either 24h or 7d PI in 3-month-old APP/PS1 mice or Wt mice. Nine-month-old APP/PS1 mice demonstrate cortical Aβ plaques but focal injury had no statistically significant (p>0.05) effect on thioflavine-S or MOAB-2 plaque load surrounding the injury site at 24h PI or 7d PI. There was a significant (p 0.05). For both Wt and APP/PS1 mice alike, synaptophysin puncta near the injury site were significantly reduced 24h PI (compared to sites distant to the injury and the corresponding area in sham mice p 0.05). There was no significant effect of genotype on this response (p>0.05). These results indicate that focal brain injury and the associated microglial response do not acutely alter Aβ plaque deposition in the APP/PS1 mouse model. Furthermore the current study demonstrated that the brains of both Wt and APP/PS1 mice are capable of recovering lost synaptophysin immunoreactivity post-injury, the latter in the presence of Aβ plaque pathology that causes synaptic degeneration.

The Influence of Genetic Factors and Cognitive Reserve on Structural and Functional Resting-State Brain Networks in Aging and Alzheimer’s Disease

Publisher: Frontiers Media SA

Date: 25-08-190728635

DOI: 10.3389/FNAGI.2019.00030

Implications for microglial sex differences in tau-related neurodegenerative diseases

Publisher: Elsevier BV

Date: 09-2021

DOI: 10.1016/J.NEUROBIOLAGING.2021.03.010

TDP-43 mislocalization drives neurofilament changes in a novel model of TDP-43 proteinopathy

Publisher: The Company of Biologists

Date: 02-2021

DOI: 10.1242/DMM.047548

Abstract: Mislocalization of the TAR DNA-binding protein 43 (TDP-43 encoded by TARDBP) from the nucleus to the cytoplasm is a common feature of neurodegenerative conditions such as amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). The downstream in vivo cellular effects of this mislocalization are not well understood. To investigate the impact of mislocalized TDP-43 on neuronal cell bodies, axons and axonal terminals, we utilized the mouse visual system to create a new model of TDP-43 proteinopathy. Mouse (C57BL/6J) retinal ganglion cells (RGCs) were transduced with GFP-tagged human wild-type TDP-43 (hTDP-WT-GFP) and human TDP-43 with a mutation in the nuclear localization sequence (hTDP-ΔNLS-GFP), to cause TDP-43 mislocalization, with ∼60% transduction efficiency achieved. Expression of both hTDP-WT-GFP and hTDP-ΔNLS-GFP resulted in changes to neurofilament expression, with cytoplasmic TDP-43 being associated with significantly (P& .05) increased neurofilament heavy expression in the cell soma, and both forms of altered TDP-43 leading to significantly (P& .05) decreased numbers of neurofilament-positive axons within the optic nerve. Alterations to neurofilament proteins were associated with significantly (P& .05) increased microglial density in the optic nerve and retina. Furthermore, expression of hTDP-WT-GFP was associated with a significant (P& .05) increase in pre-synaptic input into RGCs in the retina. The current study has developed a new model that allows detailed examination of alterations to TDP-43 and will contribute to the knowledge of TDP-43-mediated neuronal alterations and degeneration.

Microglia and motor neurons during disease progression in the SOD1G93A mouse model of amyotrophic lateral sclerosis: changes in arginase1 and inducible nitric oxide synthase

Publisher: Springer Science and Business Media LLC

Date: 23-03-2014

DOI: 10.1186/1742-2094-11-55

Enhanced anti-amyloid effect of combined leptin and pioglitazone in APP/PS1 transgenic mice

Publisher: Cold Spring Harbor Laboratory

Date: 24-06-2020

DOI: 10.1101/2020.06.24.168518

Abstract: Alzheimer’s disease (AD) has challenged single-target therapeutic strategies, raising the possibility that combined therapies may offer a more effective treatment strategy. There is substantial evidence for the efficacy of leptin (L) (neuroprotective hormone) and pioglitazone (P) (anti-inflammatory agent) as monotherapies in AD. We have previouly shown that combination treatment of L+P in APP/PS1 mice at the onset of pathology significantly improved memory and reduced brain Aβ levels relative to control mice. In this new study, we sought to replicate our previous findings in a new cohort of APP/PS1 mouse to further confirm whether the combined treatment of L+P is superior to each treatment in idually. We have re-evaluated the effects of L+P co-treatment in APP/PS1 mice using thioflavin-S staining, MOAβ immunolabeling and enzyme-linked immunosorbent assay (ELISA) to examine effects on Aβ levels and pathology, relative to animals that received L or P in idually. To explore mechanism of regulation, we used Western blotting to examine the expression of the peroxisome-proliferator activated receptor γ (PPARγ), due to its potential role in the regulation of the inflammatory response. We demonstrated that combining L and P significantly enhances the anti-Aβ effect of L or P in the hippoc us of APP/PS1 mice. Western blot analysis indicated that Aβ reduction was accompanied by up-regulation of the PPARγ levels. Our findings suggest that combining L and P significantly enhances the anti-Aβ effect of L or P in the hippoc us of APP/PS1 mice, and may be a potential new effective strategy for AD therapy.

Degeneration of axons in spinal white matter in G93A mSOD1 mouse characterized by NFL and alpha-internexin immunoreactivity

Publisher: Elsevier BV

Date: 07-2012

DOI: 10.1016/J.BRAINRES.2012.05.018

Abstract: Axonal degeneration is a prominent feature of amyotrophic lateral sclerosis (ALS) both in lower motor nerves as well as descending white matter axons in the spinal cord of human patients. Although the pathology of lower motor axonal degeneration has been described in both human ALS and related transgenic animal models, few studies have examined the pathological features of descending axon degeneration, particularly in mouse models of ALS. We have examined the degeneration of white matter tracts in the G93A mutant superoxide dismutase-1 (mSOD1+) mouse spinal cord white matter from 12 weeks of age to end-stage disease. In a G93A mSOD1 mouse model where green fluorescent protein was expressed in neurons (mSOD1+/GFP+), degeneration of white matter tracts was present from the ventral to dorsolateral funiculi. This pattern of axonal pathology occurred from 16 weeks of age. However, the dorsal funiculus, the site of the major corticospinal tract in mice, showed relatively less degeneration. Immunohistochemical analysis demonstrated that the neurofilament light chain (NFL) and neuronal intermediate filament protein alpha-internexin accumulated in axon swellings in the spinal white matter. Increased levels of alpha-internexin protein, in mSOD1+ mouse spinal cord tissue, were demonstrated by Western blotting. In contrast, degenerating axons did not show obvious accumulations of neurofilament medium and heavy chain proteins (NFM and NFH). These data suggest that white matter degeneration in this mouse model of ALS is widespread and involves a specific molecular signature, particularly the accumulation of NFL and alpha-internexin proteins.

Neuroprotective upregulation of endogenous alpha-synuclein precedes ubiquitination in cultured dopaminergic neurons

Publisher: Springer Science and Business Media LLC

Date: 09-07-2010

DOI: 10.1007/S12640-010-9207-X

Abstract: α-Synuclein is the major protein component of Lewy bodies--the pathological hallmark of Parkinson's disease (PD) and Dementia with Lewy bodies (DLB). Its accumulation into intracellular aggregates is implicated in the process of Lewy body formation. However, its roles in both normal function, and disease, remain controversial. Using a novel model of chronic oxidative stress in cultured dopaminergic and cortical neurons, we report that endogenous α-synuclein is upregulated in response to low dose toxicity. This response is conserved between subpopulations of cortical and dopaminergic neurons, and confers relative resistance to apoptosis following secondary insult. Additional acute oxidative stress leads to intracellular accumulation of α-synuclein. These punctate deposits colocalize with ubiquitin, which is central to proteosome-mediated protein degeneration, and is the second major component of Lewy bodies. The current results imply that differential levels of α-synuclein expression may influence neuronal vulnerability in chronic neurodegenerative diseases. They further support a 'two hit' hypothesis for Lewy body formation, whereby mild stress causes a protective upregulation of α-synuclein. However, such increased levels of α-synuclein may drive its accumulation, following additional toxic insult. Finally, these results support a common mechanism for degeneration of dopaminergic and cortical neurons, affected in PD, and DLB, respectively.

Microglia associations with brain pericytes and the vasculature are reduced in Alzheimer’s disease

Publisher: Cold Spring Harbor Laboratory

Date: 11-08-2022

DOI: 10.1101/2022.08.08.503250

Abstract: Cerebral blood flow is important for the maintenance of brain function and its dysregulation has been implicated in Alzheimer’s disease (AD). Subpopulations of microglia have well-characterised associations with the vasculature in the central nervous system but the precise relationship between microglia and cells which exist on the vasculature is not yet clear. In this study we explored the relationship between microglia and pericytes, a vessel-resident cell type that has a major role in the regulation of cerebral blood flow and maintenance of the blood brain barrier. Using fixed tissue sections and in vivo live imaging, we discovered a subset of microglia that closely associated with pericytes, termed PE ricyte-associated M icroglia (PEM). PEM are present throughout all regions of the brain and spinal cord in NG2DsRed x CX 3 CR1 +/GFP mice, and in the human frontal cortex. They reside adjacent to pericytes at all levels of the capillary tree and can maintain their position for at least 28 days. PEM associate with pericytes lacking astroglial endfeet coverage but are segregated from pericytes by capillary basement membranes and capillary vessel width is similarly increased beneath pericytes with or without an associated PEM. Deletion of the microglia fractalkine receptor (CX 3 CR1) did not disrupt the association between pericytes and PEM, suggesting the association is not reliant on fractalkine signalling. Finally, we found that the proportion of microglia that are capillary-associated and PEM declines in the superior frontal gyrus (SFG) in AD, which is exacerbated by the APOE ε3/ε4 genotype. In summary, we identify and characterise a subpopulation of microglia that specifically associate with pericytes and find this population is reduced in the SFG in AD. This reduction may be a novel mechanism contributing to vascular dysfunction in diseases such as AD.

Poor oral hygiene, oral microorganisms and aspiration pneumonia risk in older people in residential aged care: a systematic review

Publisher: Oxford University Press (OUP)

Date: 17-07-2020

DOI: 10.1093/AGEING/AFAA102

Abstract: aspiration pneumonia increases hospitalisation and mortality of older people in residential aged care. determine potentially pathogenic microorganisms in oral specimens of older people with aspiration pneumonia and the effect of professional oral care in reducing aspiration pneumonia risk. PUBMED/MEDLINE, CINAHL, EMBASE, COCHRANE, PROQUEST, Google Scholar, Web of Science. published between January 2001 and December 2019 addressing oral microorganisms, aspiration pneumonia, oral health and treatment. people 60 years and older in residential aged care. the Newcastle–Ottawa Scale and the Standard Protocol Items: Recommendations for Intervention Trials checklist. twelve studies (four cross-sectional, five cohort and three intervention) reported colonisation of the oral cavity of older people by microorganisms commonly associated with respiratory infections. Aspiration pneumonia occurred less in people who received professional oral care compared with no such care. Isolation of Candida albicans, Staphylococcus aureus, methicillin-resistant S. aureus and Pseudomonas aeruginosa was related to mortality due to aspiration pneumonia. An interesting finding was isolation of Escherichia coli, a gut bacterium. more information may be present in publications about other co-morbidities that did not meet inclusion criteria. A high degree of heterogeneity prevented a meta-analysis. Issues included s ling size, no power and effect size calculations different oral health assessments how oral specimens were analysed and how aspiration pneumonia was diagnosed. pathogenic microorganisms colonising the oral microbiome are associated with aspiration pneumonia in older people in residential care professional oral hygiene care is useful in reducing aspiration pneumonia risk.

Temporal changes in the microglial proteome of male and female mice after a diffuse brain injury using label-free quantitative proteomics

Publisher: Wiley

Date: 05-12-2022

DOI: 10.1002/GLIA.24313

Abstract: Traumatic brain injury (TBI) triggers neuroinflammatory cascades mediated by microglia, which promotes tissue repair in the short‐term. These cascades may exacerbate TBI‐induced tissue damage and symptoms in the months to years post‐injury. However, the progression of the microglial function across time post‐injury and whether this differs between biological sexes is not well understood. In this study, we examined the microglial proteome at 3‐, 7‐, or 28‐days after a midline fluid percussion injury (mFPI) in male and female mice using label‐free quantitative proteomics. Data are available via ProteomeXchange with identifier PXD033628. We identified a reduction in microglial proteins involved with clearance of neuronal debris via phagocytosis at 3‐ and 7‐days post‐injury. At 28 days post‐injury, pro‐inflammatory proteins were decreased and anti‐inflammatory proteins were increased in microglia. These results indicate a reduction in microglial clearance of neuronal debris in the days post‐injury with a shift to anti‐inflammatory function by 28 days following TBI. The changes in the microglial proteome that occurred across time post‐injury did not differ between biological sexes. However, we did identify an increase in microglial proteins related to pro‐inflammation and phagocytosis as well as insulin and estrogen signaling in males compared with female mice that occurred with or without a brain injury. Although the microglial response was similar between males and females up to 28 days following TBI, biological sex differences in the microglial proteome, regardless of TBI, has implications for the efficacy of treatment strategies targeting the microglial response post‐injury.

The Island Study Linking Ageing and Neurodegenerative Disease (ISLAND): A longitudinal public health research program targeting dementia risk reduction

Publisher: Wiley

Date: 12-2020

DOI: 10.1002/ALZ.045539

An online, public health framework supporting behaviour change to reduce dementia risk: interim results from the ISLAND study linking ageing and neurodegenerative disease

Publisher: Springer Science and Business Media LLC

Date: 29-09-2023

DOI: 10.1186/S12889-023-16805-2

Methods for in vivo CRISPR/cas editing of the adult murine retina

Publisher: Springer New York

Date: 30-11-2018

DOI: 10.1007/978-1-4939-7522-8_9

Abstract: Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated protein (Cas) is used by some bacteria and most archaea to protect against viral phage intrusion and has recently been adapted to allow for efficient editing of the mammalian genome. Whilst CRISPR/Cas-based technology has been used to modify genes in mammalian cells in vitro, delivery of CRISPR/Cas system into mammalian tissue and/or organs is more difficult and often requires additional vectors. With the use of adeno-associated virus (AAV) gene delivery system, active CRISPR/Cas enzyme can be maintained for an extended period of time and enable efficient editing of genome in the retina in vivo. Herein we outline the method to edit the genome in mouse retina using a dual AAV vector -mediated CRISPR/Cas9 system.

Reducing aspiration pneumonia risk for older people: effect of evidence-based oral care

Publisher: Oxford University Press (OUP)

Date: 12-2021

DOI: 10.1093/GERONI/IGAB046.1408

Abstract: Poor oral health increases the risk of aspiration pneumonia for older people. This is due primarily to six pathogens found in the mouth: five bacteria and one fungus. With a cohort of older people who were dependent on others for their oral care, we analyzed the load and type of bacteria and fungi from swabs of cheek, gum, and tongue mucosa. There were no significant differences between the three sites for load of bacteria (H (2) = .89 p = .64) there were significant differences between the sites for type of bacteria (F (2,78) = 11.97 p & .001) with the tongue showing the greatest ersity. There were no significant differences between the three sites for load (H (2) = 2.94 p = .23) or type (F (2,77) = .46 p = .63) of fungi. We then investigated the effect of regular compared to evidence-based oral care over a six-week period, and whether evidence-based oral care could significantly reduce the absolute count of the six oral pathogens specifically related to aspiration pneumonia. Participants self-selected into Regular Care (n = 10) and Evidence-based Care (n = 17) Groups. Evidence-based oral care resulted in significant decreases (p = .02 to p & .001) in the load of four potentially pathogenic bacterial species, including E. coli, gut-based bacteria, and in an increased load of Lactobacillus reuteri, a host-protective normal flora in the mouth, compared to baseline. There were no significant differences between groups for the abundance and type of fungi.

AAV-mediated gene delivery of the calreticulin anti-angiogenic domain inhibits ocular neovascularization

Publisher: Springer Science and Business Media LLC

Date: 09-01-2018

DOI: 10.1007/S10456-017-9591-4

Abstract: Ocular neovascularization is a common pathological feature in diabetic retinopathy and neovascular age-related macular degeneration that can lead to severe vision loss. We evaluated the therapeutic efficacy of a novel endogenous inhibitor of angiogenesis, the calreticulin anti-angiogenic domain (CAD180), and its functional 112-residue fragment, CAD-like peptide 112 (CAD112), delivered using a self-complementary adeno-associated virus serotype 2 (scAAV2) in rodent models of oxygen-induced retinopathy and laser-induced choroidal neovascularization. The expression of CAD180 and CAD112 was elevated in human umbilical vein endothelial cells transduced with scAAV2-CAD180 or scAAV2-CAD112, respectively, and both inhibited angiogenic activity in vitro. Intravitreal gene delivery of scAAV2-CAD180 or scAAV2-CAD112 significantly inhibited ischemia-induced retinal neovascularization in rat eyes (CAD180: 52.7% reduction CAD112: 49.2% reduction) compared to scAAV2-mCherry, as measured in retinal flatmounts stained with isolectin B4. Moreover, the retinal structure and function were unaffected by scAAV2-CAD180 or scAAV2-CAD112, as measured by optical coherence tomography and electroretinography. Moreover, subretinal delivery of scAAV2-CAD180 or scAAV2-CAD112 significantly attenuated laser-induced choroidal neovascularization in mouse eyes compared to scAAV2-mCherry, as measured by fundus fluorescein angiography (CAD180: 62.4% reduction CAD112: 57.5% reduction) and choroidal flatmounts (CAD180: 40.21% reduction CAD112: 43.03% reduction). Gene delivery using scAAV2-CAD180 or scAAV2-CAD112 has significant potential as a therapeutic option for the management of ocular neovascularization.

Disruption of leptin signalling in a mouse model of Alzheimer’s disease

Publisher: Springer Science and Business Media LLC

Date: 15-03-2018

DOI: 10.1007/S11011-018-0203-9

Abstract: Disruption of leptin signalling has been implicated as playing a role in the development of Alzheimer's disease (AD). Leptin has previously been shown to be affected by amyloid-beta (Aβ)-related signalling however, pathways that link leptin to the disease pathogenesis have not been determined. To characterize the association between increasing age-dependent Aβ levels with leptin signalling and the vulnerable brain regions in AD, we assessed the mRNA and protein expression profile of leptin and leptin receptor (Ob-Rb) at 9 and 18-month-age in APP/PS1 mice. Immunohistochemical labelling demonstrated that leptin and Ob-Rb proteins were localised to neocortical and hippoc al neurons in APP/PS1 and wildtype (WT) mice. Neuronal leptin and Ob-Rb immunolabelling was more prominent in the neocortex of both groups at 9 month of age, while, at 18 months, labelling was reduced in the hippoc us of APP/PS1 mice relative to WT. Immunoblotting analysis demonstrated decreased hippoc al leptin levels, concomitantly with an increased Ob-Rb levels, in APP/PS1 mice compared with WT controls at 18 month of age. While no leptin mRNA was found in either of the groups analysed, Ob-Rb mRNA was significantly decreased in the hippoc us of APP/PS1 mice at both ages analysed. In addition, a significant decreased protein kinase B (Akt) activity concomitantly with an upregulation of suppressor of cytokine signaling-3 (SOCS3) and protein-tyrosine phosphatase 1B (PTP1B) transcripts was present. Thus, these results collectively indicate alterations of leptin signalling in the hippoc us of APP/PS1 mice, providing novel insights about the pathways that could link aberrant leptin signaling to the pathological changes of AD.

Repeat propofol anesthesia does not exacerbate plaque deposition or synapse loss in APP/PS1 Alzheimer’s disease mice

Publisher: Springer Science and Business Media LLC

Date: 25-04-2018

DOI: 10.1186/S12871-018-0509-5

AAV-Mediated CRISPR/Cas Gene Editing of Retinal Cells In Vivo

Publisher: Association for Research in Vision and Ophthalmology (ARVO)

Date: 29-06-2016

DOI: 10.1167/IOVS.16-19316

Abstract: Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated protein (Cas) has recently been adapted to enable efficient editing of the mammalian genome, opening novel avenues for therapeutic intervention of inherited diseases. In seeking to disrupt yellow fluorescent protein (YFP) in a Thy1-YFP transgenic mouse, we assessed the feasibility of utilizing the adeno-associated virus 2 (AAV2) to deliver CRISPR/Cas for gene modification of retinal cells in vivo. Single guide RNA (sgRNA) plasmids were designed to target YFP, and after in vitro validation, selected guides were cloned into a dual AAV system. One AAV2 construct was used to deliver Streptococcus pyogenes Cas9 (SpCas9), and the other delivered sgRNA against YFP or LacZ (control) in the presence of mCherry. Five weeks after intravitreal injection, retinal function was determined using electroretinography, and CRISPR/Cas-mediated gene modifications were quantified in retinal flat mounts. Adeno-associated virus 2-mediated in vivo delivery of SpCas9 with sgRNA targeting YFP significantly reduced the number of YFP fluorescent cells of the inner retina of our transgenic mouse model. Overall, we found an 84.0% (95% confidence interval [CI]: 81.8-86.9) reduction of YFP-positive cells in YFP-sgRNA-infected retinal cells compared to eyes treated with LacZ-sgRNA. Electroretinography profiling found no significant alteration in retinal function following AAV2-mediated delivery of CRISPR/Cas components compared to contralateral untreated eyes. Thy1-YFP transgenic mice were used as a rapid quantifiable means to assess the efficacy of CRISPR/Cas-based retinal gene modification in vivo. We demonstrate that genomic modification of cells in the adult retina can be readily achieved by viral-mediated delivery of CRISPR/Cas.

Sex-Specific Protective Effects of Cognitive Reserve on Age-Related Cognitive Decline

Publisher: Ovid Technologies (Wolters Kluwer Health)

Date: 10-01-2023

DOI: 10.1212/WNL.0000000000201369

Abstract: Females have a higher age-adjusted incidence of Alzheimer disease than males but the reasons for this remain unclear. One proposed contributing factor is that, historically, females had less access to education and, therefore, may accumulate less cognitive reserve. However, educational attainment is confounded by IQ, which in itself is a component of cognitive reserve and does not differ between sexes. Steeper age-related cognitive declines are associated with increased risk of dementia. We, therefore, evaluated the moderating effects of 2 proxies for cognitive reserve, education and IQ, on the steepness of age-related declining cognitive trajectories in unimpaired older males and females. The Tasmanian Healthy Brain Project, a long-term cohort study, recruited healthy Australians aged 50–80 years without cognitive impairment. Baseline cognitive reserve was measured using educational history and IQ, measured by the Wechsler Test of Adult Reading, Full Scale Predicted IQ (WTAR-FSIQ). Cognitive trajectories for language, executive function, and episodic and working memory over 5 years were extracted from neuropsychological assessments. The adjusted effects of education, estimated IQ, and APOE allelic variant on cognitive trajectories were compared between males and females. Five hundred sixty-two in iduals (mean [SD] age 60 [6.7] years 68% male 33% APOE ε4+) were followed up over 5 years with 1,924 assessments and 24,946 cognitive test scores (annualized attrition rate 6.6% per year). Estimated IQ correlated with years of education ( p 0.001). Estimated IQ interacted with sex to moderate age-related cognitive trajectories ( p = 0.03 adjusted for education) lower IQ males experienced steeper declining trajectories than higher IQ males, but lower IQ females had similar steepness of declining trajectories to higher IQ females. Education was not associated with rate of cognitive decline ( p = 0.67 adjusted for WTAR-FSIQ). There were no significant differences in age-related cognitive trajectories between APOE genotypes in either sex. IQ, a measure of cognitive reserve, predicted the steepness of declining cognitive trajectories in males only. Education did not explain as much variation in cognitive trajectories as IQ. Our findings do not support the hypothesis that historical sex disparities in access to education contribute to the higher female incidence of Alzheimer disease.

Association between chronic pain and risk of incident dementia: findings from a prospective cohort

Publisher: Springer Science and Business Media LLC

Date: 04-05-2023

DOI: 10.1186/S12916-023-02875-X

Abstract: Chronic musculoskeletal pain has been linked to dementia however, chronic pain typically occurs in multiple sites therefore, this study was to investigate whether greater number of chronic pain sites is associated with a higher risk of dementia and its subtypes. Participants ( N = 356,383) in the UK Biobank who were dementia-free at baseline were included. Pain in the hip, knee, back, and neck/shoulder or ‘all over the body’ and its duration were assessed. Participants were categorised into six groups: no chronic pain chronic pain in 1, 2, 3, and 4 sites, and ‘all over the body’. All-cause dementia and its subtypes were ascertained using hospital inpatient and death registry records. Cox regression was used to investigate the associations between the number of chronic pain sites and the incidence of all-cause dementia and its subtypes. Over a median follow-up of 13 years, 4959 participants developed dementia. After adjustment for sociodemographic, lifestyle, comorbidities, pain medications, psychological problems, and sleep factors, greater number of chronic pain sites was associated with an increased risk of incident all-cause dementia (hazard ratio [HR] = 1.08 per 1 site increase, 95% CI 1.05–1.11) and Alzheimer’s disease (AD) (HR = 1.09 per 1-site increase, 95% CI 1.04–1.13) in a dose–response manner but not vascular and frontotemporal dementia. No significant association was found between the number of chronic pain sites and the risk of incident all-cause dementia among a subs le that underwent a fluid intelligence test. Greater number of chronic pain sites was associated with an increased risk of incident all-cause dementia and AD, suggesting that chronic pain in multiple sites may contribute to in iduals’ dementia risk and is an underestimated risk factor for dementia.

Amyloid β accumulation and inner retinal degenerative changes in Alzheimer’s disease transgenic mouse

Publisher: Elsevier BV

Date: 06-2016

DOI: 10.1016/J.NEULET.2016.04.059

Abstract: The APP-PS1ΔE9 mouse model of Alzheimer's disease (AD) exhibits age dependent amyloid β (Aβ) plaque formation in their central nervous system due to high expression of mutated human APP and PSEN1 transgenes. Here we evaluated Aβ deposition and changes in soluble Aβ accumulation in the retinas of aged APP-PS1 mice using a combination of immunofluorescence, retinal flat mounts and western blotting techniques. Aβ accumulation in the retina has previously been shown to be associated with retinal ganglion cell apoptosis in animal models of glaucoma. This study investigated changes in the inner retinal function and structure in APP-PS1 mice using electrophysiology and histological approaches respectively. We report for the first time a significant decline in scotopic threshold response (STR) litudes which represents inner retinal function in transgenic animals compared to the wild type counterparts (p<0.0001). Thinning of the retina particularly involving inner retinal layers and reduction in axonal density in the optic nerve was also observed. TUNEL staining was performed to examine neuronal apoptosis in the inner retina. Intraocular pressure (IOP) measurements showed that APP-PS1ΔE9 mice had a slightly elevated IOP, but the significance of this finding is not yet known. Together, these results substantiate previous observations and highlight that APP-PS1ΔE9 mice show evidence of molecular, functional and morphological degenerative changes in the inner retina.

Associations of Later-Life Education, the BDNF Val66Met Polymorphism and Cognitive Change in Older Adults

Publisher: SERDI

Date: 2019

DOI: 10.14283/JPAD.2019.40

Abstract: In 358 participants of the Tasmanian Healthy Brain Project, we quantified the cognitive consequences of engaging in varying loads of university-level education in later life, and investigated whether or not BDNF Val66Met affected outcomes. Assessment of neuropsychological, health, and psychosocial function was undertaken at baseline, 12-month, and 24-month follow-up. Education load was positively associated with change in language processing performance, but this effect did not reach statistical significance (P = 0.064). The BDNF Val66Met polymorphism significantly moderated the extent to which education load was associated with improved language processing (P = 0.026), with education load having a significant positive relationship with cognitive change in BDNF Met carriers but not in BDNF Val homozygotes. In older adults who carry BDNF Met, engaging in university-level education improves language processing performance in a load-dependent manner.

Alzheimer’s disease and NQO1: Is there a link?

Publisher: Bentham Science Publishers Ltd.

Date: 21-12-2018

DOI: 10.2174/1567205014666170203095802

Abstract: Alzheimer's disease (AD) is a neurodegenerative disease characterised by a progressive decline in cognitive function and represents a major healthcare challenge worldwide. Increasing evidence indicates that mitochondrial dysfunction mediated oxidative stress plays a significant role in the pathophysiological process of AD. Therefore, the physiological activation of antioxidant enzymes that respond to increased oxidative stress is thought to prevent neuropathology. One of those endogenous defences is NADPH quinone oxidoreductase 1 (NQO1). NQO1 is a cytosolic homodimeric flavoprotein that catalyses the two-electron reduction of quinones and related molecules aimed at increasing their solubility and excretion. In line with its role as a phase II stress response protein, altered NQO1 expression is associated with several pathological conditions and disorders including AD. This review summarizes the association between NQO1 and AD pathology. Understanding this association will provide further insight into the pathogenesis of the disease. More importantly, recent interest in drugs that affect NQO1 expression or its activity provides hope that this approach could lead to novel therapeutic options for the treatment of AD.

Diffuse axonal injury in brain trauma: insights from alterations in neurofilaments

Publisher: Frontiers Media SA

Date: 17-12-2014

DOI: 10.3389/FNCEL.2014.00429

Island Study Linking Aging and Neurodegenerative Disease (ISLAND) Targeting Dementia Risk Reduction: Protocol for a Prospective Web-Based Cohort Study (Preprint)

Publisher: JMIR Publications Inc.

Date: 04-11-2021

DOI: 10.2196/PREPRINTS.34688

Abstract: p to 40% of incident dementia is considered attributable to behavioral and lifestyle factors. Given the current lack of medical treatments and the projected increase in dementia prevalence, a focus on prevention through risk reduction is needed. e aim to increase dementia risk knowledge and promote changes in dementia risk behaviors at in idual and population levels. he Island Study Linking Aging and Neurodegenerative Disease (ISLAND) is a long-term prospective, web-based cohort study with nested interventions that will be conducted over a 10-year period. Target participants (n=10,000) reside in Tasmania and are aged 50 years or over. Survey data on knowledge, attitudes, and behaviors related to modifiable dementia risk factors will be collected annually. After each survey wave, participants will be provided with a personalized dementia risk profile containing guidelines for reducing risk across 9 behavioral and lifestyle domains and with opportunities to engage in educational and behavioral interventions targeting risk reduction. Survey data will be modeled longitudinally with intervention engagement indices, cognitive function indices, and blood-based biomarkers, to measure change in risk over time. n the initial 12 months (October 2019 to October 2020), 6410 participants have provided baseline data. The study is ongoing. ecruitment targets are feasible and efforts are ongoing to achieve a representative s le. Findings will inform future public health dementia risk reduction initiatives by showing whether, when, and how dementia risk can be lowered through educational and behavioral interventions, delivered in an uncontrolled real-world context. ERR1-10.2196/34688

Chronic Excitotoxin-Induced Axon Degeneration in a Compartmented Neuronal Culture Model

Publisher: SAGE Publications

Date: 2012

DOI: 10.1042/AN20110031

Abstract: Glutamate excitotoxicity is a major pathogenic process implicated in many neurodegenerative conditions, including AD (Alzheimer's disease) and following traumatic brain injury. Occurring predominantly from over-stimulation of ionotropic glutamate receptors located along dendrites, excitotoxic axonal degeneration may also occur in white matter tracts. Recent identification of axonal glutamate receptor subunits within axonal nanocomplexes raises the possibility of direct excitotoxic effects on axons. In idual neuronal responses to excitotoxicity are highly dependent on the complement of glutamate receptors expressed by the cell, and the localization of the functional receptors. To enable isolation of distal axons and targeted excitotoxicity, murine cortical neuron cultures were prepared in compartmented microfluidic devices, such that distal axons were isolated from neuronal cell bodies. Within the compartmented culture system, cortical neurons developed to relative maturity at 11 DIV (days in vitro) as demonstrated by the formation of dendritic spines and clustering of the presynaptic protein synaptophysin. The isolated distal axons retained growth cone structures in the absence of synaptic targets, and expressed glutamate receptor subunits. Glutamate treatment (100 μM) to the cell body chamber resulted in widespread degeneration within this chamber and degeneration of distal axons in the other chamber. Glutamate application to the distal axon chamber triggered a lesser degree of axonal degeneration without degenerative changes in the untreated somal chamber. These data indicate that in addition to current mechanisms of indirect axonal excitotoxicity, the distal axon may be a primary target for excitotoxicity in neurodegenerative conditions.

Cover Image, Volume 71, Issue 8

Publisher: Wiley

Date: 11-06-2023

DOI: 10.1002/GLIA.24208

Can mature –age non-traditional students succeed in an online Bachelor of Dementia Care program?

Publisher: Oxford University Press (OUP)

Date: 30-06-2017

DOI: 10.1093/GERONI/IGX004.1399

Enhanced Anti-Amyloid Effect of Combined Leptin and Pioglitazone in APP/PS1 Transgenic Mice

Publisher: Bentham Science Publishers Ltd.

Date: 05-03-2021

DOI: 10.2174/1567205018666210218163857

Abstract: Alzheimer’s disease (AD) has challenged single-target therapeutic strategies, raising the possibility that combined therapies may offer a more effective treatment strategy. There is substantial evidence for the efficacy of leptin (L) (neuroprotective hormone) and pioglitazone (P) (anti-inflammatory agent) as monotherapies in AD. We have previously shown that combination treatment of L+P in APP/PS1 mice at the onset of pathology significantly improved memory and reduced brain Aβ levels relative to control mice. In this new study, we sought to replicate our previous findings in a new cohort of APP/PS1 mice to further confirm whether the combined treatment of L+P is superior to each treatment in idually. : We have re-evaluated the effects of L+P co-treatment in APP/PS1 mice using thioflavin-S staining, MOAβ immunolabeling, and enzyme-linked immunosorbent assay (ELISA) to examine effects on Aβ levels and pathology, relative to animals that received L or P in idually. We demonstrated that a combination of L and P significantly enhances the anti-Aβ effect of L or P in the hippoc us of APP/PS1 mice. Our findings suggest that combining L and P significantly enhances the anti-Aβ effect of L or P in the hippoc us of APP/PS1 mice and maybe a potential new effective strategy for AD therapy.

The role of altered protein acetylation in neurodegenerative disease

Publisher: Frontiers Media SA

Date: 04-01-2023

DOI: 10.3389/FNAGI.2022.1025473

Abstract: Acetylation is a key post-translational modification (PTM) involved in the regulation of both histone and non-histone proteins. It controls cellular processes such as DNA transcription, RNA modifications, proteostasis, aging, autophagy, regulation of cytoskeletal structures, and metabolism. Acetylation is essential to maintain neuronal plasticity and therefore essential for memory and learning. Homeostasis of acetylation is maintained through the activities of histone acetyltransferases (HAT) and histone deacetylase (HDAC) enzymes, with alterations to these tightly regulated processes reported in several neurodegenerative diseases including Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), and amyotrophic lateral sclerosis (ALS). Both hyperacetylation and hypoacetylation can impair neuronal physiological homeostasis and increase the accumulation of pathophysiological proteins such as tau, α-synuclein, and Huntingtin protein implicated in AD, PD, and HD, respectively. Additionally, dysregulation of acetylation is linked to impaired axonal transport, a key pathological mechanism in ALS. This review article will discuss the physiological roles of protein acetylation and examine the current literature that describes altered protein acetylation in neurodegenerative disorders.

Does serum neurofilament light help predict accelerated cognitive ageing in unimpaired older adults?

Publisher: Frontiers Media SA

Date: 10-08-2023

DOI: 10.3389/FNINS.2023.1237284

Abstract: Neurofilament light (NfL) is a blood biomarker of neurodegeneration. While serum NfL levels have been demonstrated to increase with normal ageing, the relationship between serum NfL levels and normal age-related changes in cognitive functions is less well understood. The current study investigated whether cross-sectional serum NfL levels measured by single molecule array technology (Simoa®) mediated the effect of age on cognition, measured by a battery of neuropsychological tests administered biannually for 8 years, in a cohort of 174 unimpaired older adults (≥50 years) from the Tasmanian Healthy Brain Project. Mediation analysis was conducted using latent variables representing cognitive test performance on three cognitive domains - episodic memory, executive function, and language (vocabulary, comprehension, naming). Cognitive test scores for the three domains were estimated for each participant, coincident with blood collection in 2018 using linear Bayesian hierarchical models. Higher serum NfL levels were significantly positively associated with age ( p & 0.001 for all domains). Cognitive test scores were significantly negatively associated with age across the domains of executive function ( p & 0.001), episodic memory ( p & 0.001) and language ( p & 0.05). However, serum NfL levels did not significantly mediate the relationship between age and cognitive test scores across any of the domains. This study adds to the literature on the relationship between serum NfL levels and cognition in unimpaired older adults and suggests that serum NfL is not a pre-clinical biomarker of ensuing cognitive decline in unimpaired older adults.

HDAC6 inhibition as a mechanism to prevent axon degeneration in the mSOD1^G93Amouse model of ALS

Publisher: Cold Spring Harbor Laboratory

Date: 29-08-2023

DOI: 10.1101/2023.08.28.555025

Abstract: The loss of upper and lower motor neurons, and their axons is central to the loss of motor function and death in amyotrophic lateral sclerosis (ALS). Due to the erse range of genetic and environmental factors that contribute to the pathogenesis of ALS, there have been difficulties in developing effective therapies for ALS. One dichotomy emerging in the field is that protection of the neuronal cell soma itself does not prevent axonal vulnerability and degeneration, suggesting the need for targeted therapeutics to prevent axon degeneration. Post-translational modifications of protein acetylation can alter the function, stability and half-life of in idual proteins, and can be enzymatically modified by histone acetyltransferases (HATs) and histone deacetyltransferases (HDACs), which add, or remove acetyl groups, respectively. Maintenance of post-translational microtubule acetylation has been suggested as a potential mechanism to stabilise axons and prevent axonal loss and neurodegeneration in ALS. This study has utilized an orally dosed HDAC6 specific inhibitor, ACY-738, prevent deacetylation and stabilize microtubules in the mSOD1G93A mouse model of ALS. Furthermore, co-treatment with riluzole was performed to determine any effects or drug interactions and potentially enhance preclinical research translation. This study shows ACY-738 treatment increased acetylation of microtubules in the spinal cord of mSOD1G93A mice, reduced lower motor neuron degeneration in the lumbar spinal cord of female mice, ameliorated reduction in peripheral nerve axon puncta size, but did not prevent overt motor function decline. The current study also shows peripheral nerve axon puncta size to be partially restored after treatment with riluzole and highlights the importance of co-treatment to measure the potential effects of therapeutics in ALS.

Cytoskeletal changes during development and aging in the cortex of neurofilament light protein knockout mice

Publisher: Wiley

Date: 04-04-2013

DOI: 10.1002/CNE.23261

Abstract: The neurofilament light (NFL) subunit is considered as an obligate subunit polymer for neuronal intermediate filaments comprising the neurofilament (NF) triplet proteins. We examined cytoskeletal protein levels in the cerebral cortex of NFL knockout (KO) mice at postnatal day 4 (P4), 5 months, and 12 months of age compared with age-matched wild-type (WT) mice of a similar genetic background (C57BL/6). The absence of NFL protein resulted in a significant reduction of phosphorylated and dephosphorylated NFs (NF-P, NF-DP), the medium NF subunit (NFM), and the intermediate filament α-internexin (INT) at P4. At 5 months, NF-DP, NFM, and INT remained significantly lower in knockouts. At 12 months, NF-P was again significantly decreased, and INT significantly increased, in KOs compared with wild type. In addition, protein levels of class III neuron-specific β-tubulin and microtubule-associated protein 2 were significantly increased in NFL KO mice at P4, 5 months, and 12 months, whereas β-actin levels were significantly decreased at P4. Immunocytochemical studies demonstrated that NF-DP accumulated abnormally in the perikarya of cortical neurons by 5 months of age in NFL KO mice. Neurons that lacked NF triplet proteins, such as calretinin-immunolabeled nonpyramidal cells, showed no alterations in density or cytoarchitectural distribution in NFL KO mice at 5 months relative to WT mice, although calretinin protein levels were decreased significantly after 12 months in NFL KO mice. These findings suggest that a lack of NFL protein alters the expression of cytoskeletal proteins and disrupts other NF subunits, causing intracellular aggregation but not gross structural changes in cortical neurons or cytoarchitecture. The data also indicate that changes in expression of other cytoskeletal proteins may compensate for decreased NFs.

C9ORF72, implicated in amytrophic lateral sclerosis and frontotemporal dementia, regulates endosomal trafficking

Publisher: Oxford University Press (OUP)

Date: 10-08-2017

DOI: 10.1093/HMG/DDX309

University Of Tasmania

Location: No location found

View Organisation

University Of Tasmania College Of Health And Medicine

Location: Australia

View Organisation

Durham University

Location: United Kingdom of Great Britain and Northern Ireland

View Organisation

University Of Tasmania

Location: Australia

View Organisation

Advanced High Resolution Biomolecular Analysis Facility For Tasmania

Start Date: 2018

End Date: 2018

Funder: Australian Research Council

Advanced High Resolution Biomolecular Analysis Facility For Tasmania

Start Date: 2018

End Date: 2018

Funder: Australian Research Council

The Role Of Excitotoxicity In Mediating Distal Axonal Degneration In ALS

Start Date: 2011

End Date: 2014

Funder: National Health and Medical Research Council

Microfluidic Technology To Help Understand Physical Damage To Brain Cells

Start Date: 2015

End Date: 2017

Funder: Australian Research Council

Detecting Biomarkers Of Brain Health In Dementia

Start Date: 2018

End Date: 2021

Funder: National Health and Medical Research Council

Microfluidic Technology To Help Understand Physical Damage To Brain Cells

Start Date: 2015

End Date: 2017

Funder: Australian Research Council

Why Do We Have SARM 1 Protein If Knocking It Out Prevents Axons Degenerating?

Start Date: 2019

End Date: 2017

Funder: National Health and Medical Research Council

Axon Degeneration And Axon Protection In CNS Disease And Injury

Start Date: 2015

End Date: 2017

Funder: National Health and Medical Research Council

Microfluidic Models Of The CNS: Understanding Cells, Circuits & Synapses

Start Date: 2020

End Date: 2022

Funder: Australian Research Council

The Tasmanian Healthy Brain Project: A Longitudinal Intervention Study To Reduce The Risk Of Ageing-related Cognitive Decline And Dementia

Start Date: 2016

End Date: 2020

Funder: National Health and Medical Research Council

Discovery Projects - Grant ID: DP200103193

Start Date: 11-2020

End Date: 12-2024

Amount: $545,563.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP150100998

Start Date: 2015

End Date: 12-2020

Amount: $415,500.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE180100059

Start Date: 2018

End Date: 12-2018

Amount: $350,790.00

Funder: Australian Research Council