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1.
Acta Neuropathol Commun ; 12(1): 52, 2024 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-38576010

RESUMO

The transcellular propagation of the aberrantly modified protein tau along the functional brain network is a key hallmark of Alzheimer's disease and related tauopathies. Inoculation-based tau propagation models can recapitulate the stereotypical spread of tau and reproduce various types of tau inclusions linked to specific tauopathy, albeit with varying degrees of fidelity. With this systematic review, we underscore the significance of judicious selection and meticulous functional, biochemical, and biophysical characterization of various tau inocula. Furthermore, we highlight the necessity of choosing suitable animal models and inoculation sites, along with the critical need for validation of fibrillary pathology using confirmatory staining, to accurately recapitulate disease-specific inclusions. As a practical guide, we put forth a framework for establishing a benchmark of inoculation-based tau propagation models that holds promise for use in preclinical testing of disease-modifying drugs.


Assuntos
Doença de Alzheimer , Tauopatias , Animais , Doença de Alzheimer/patologia , Emaranhados Neurofibrilares/patologia , Modelos Animais de Doenças , Tauopatias/patologia , Proteínas tau/metabolismo , Encéfalo/patologia
2.
Microb Biotechnol ; 17(4): e14462, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38593310

RESUMO

Alzheimer's disease is a complex and progressive condition that affects essential neurological functions such as memory and reasoning. In the brain, neuronal loss, synaptic dysfunction, proteinopathy, neurofibrillary tangles, and neuroinflammation are the hallmarks of Alzheimer's disease pathophysiology. In addition, recent evidence has highlighted that microbes, whether commensal or pathogenic, also have the ability to interact with their host and to regulate its immune system, therefore participating in the exchanges that lead to peripheral inflammation and neuropathology. Because of this intimate relationship, bacteria, viruses, fungi, and protozoa have been implicated in the development of Alzheimer's disease. Here, we bring together current and most recent evidence of the role of microbes in Alzheimer's disease, raising burning questions that need to be addressed to guide therapeutic approaches and potential prophylactic strategies.


Assuntos
Doença de Alzheimer , Humanos , Doença de Alzheimer/patologia , Doença de Alzheimer/terapia , Emaranhados Neurofibrilares/patologia , Encéfalo , Inflamação/patologia
3.
Biomolecules ; 14(3)2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38540715

RESUMO

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder characterized by cognitive decline and neuropathological hallmarks, including ß-amyloid (Aß) plaques, Tau tangles, synaptic dysfunction and neurodegeneration. Emerging evidence suggests that abnormal iron (Fe) metabolism plays a role in AD pathogenesis, but the precise spatial distribution of the Fe and its transporters, such as ferroportin (FPN), within affected brain regions remains poorly understood. This study investigates the distribution of Fe and FPN in the CA1 region of the human hippocampus in AD patients with a micrometer lateral resolution using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). For this purpose, we visualized and quantified Fe and FPN in three separated CA1 layers: stratum molecular-radial (SMR), stratum pyramidal (SP) and stratum oriens (SO). Additionally, chromogenic immunohistochemistry was used to examine the distribution and colocalization with Tau and Aß proteins. The results show that Fe accumulation was significantly higher in AD brains, particularly in SMR and SO. However, FPN did not present significantly changes in AD, although it showed a non-uniform distribution across CA1 layers, with elevated levels in SP and SO. Interestingly, minimal overlap was observed between Fe and FPN signals, and none between Fe and areas rich in neurofibrillary tangles (NFTs) or neuritic plaques (NP). In conclusion, the lack of correlation between Fe and FPN signals suggests complex regulatory mechanisms in AD Fe metabolism and deposition. These findings highlight the complexity of Fe dysregulation in AD and its potential role in disease progression.


Assuntos
Doença de Alzheimer , Proteínas de Transporte de Cátions , Terapia a Laser , Humanos , Doença de Alzheimer/metabolismo , Ferro/metabolismo , Hipocampo/metabolismo , Peptídeos beta-Amiloides/metabolismo , Proteínas tau/metabolismo , Emaranhados Neurofibrilares/metabolismo , Emaranhados Neurofibrilares/patologia
4.
J Neuropathol Exp Neurol ; 83(4): 251-257, 2024 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-38456313

RESUMO

Subacute sclerosing panencephalitis (SSPE) is a fatal, slowly progressive brain disorder caused by a mutated measles virus. Both subacute inflammatory and neurodegenerative mechanisms appear to play significant roles in the pathogenesis. TAR DNA-binding protein 43 (TDP-43) inclusions are a common co-pathology in several neurodegenerative disorders with diverse pathogenesis. In the present study, we examined brains of 16 autopsied SSPE patients for the presence of TDP-43 pathology and possible associations with tau pathology. Immunohistochemical staining identified TDP-43 inclusions in 31% of SSPE cases. TDP-43 pathology was widely distributed in the brains, most severely in the atrophied cerebral cortex (temporal and parietal), and most frequently as tangle- and thread-like neuronal cytoplasmic inclusions. It was associated with longer disease duration (>4 years) and tau pathology (all TDP-43-positive cases had tau-positive neurofibrillary tangles). This study demonstrates for the first time an association between TDP-43 pathology and SSPE. The co-occurrence of TDP-43 and tau aggregates and correlation with the disease duration suggest that both pathological proteins are involved in the neurodegenerative process induced by viral inflammation.


Assuntos
Panencefalite Esclerosante Subaguda , Humanos , Panencefalite Esclerosante Subaguda/metabolismo , Panencefalite Esclerosante Subaguda/patologia , Vírus do Sarampo/metabolismo , Encéfalo/patologia , Emaranhados Neurofibrilares/patologia , Proteínas de Ligação a DNA/metabolismo , Inflamação/patologia
5.
J Alzheimers Dis ; 98(4): 1199-1218, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38517793

RESUMO

Animal models, particularly transgenic mice, are extensively used in Alzheimer's disease (AD) research to emulate key disease hallmarks, such as amyloid plaques and neurofibrillary tangles formation. Although these models have contributed to our understanding of AD pathogenesis and can be helpful in testing potential therapeutic interventions, their reliability is dubious. While preclinical studies have shown promise, clinical trials often yield disappointing results, highlighting a notable gap and disparity between animal models and human AD pathology. Existing models frequently overlook early-stage human pathologies and other key AD characteristics, thereby limiting their application in identifying optimal therapeutic interventions. Enhancing model reliability necessitates rigorous study design, comprehensive behavioral evaluations, and biomarker utilization. Overall, a nuanced understanding of each model's neuropathology, its fidelity to human AD, and its limitations is essential for accurate interpretation and successful translation of findings. This article analyzes the discrepancies between animal models and human AD pathology that complicate the translation of findings from preclinical studies to clinical applications. We also delve into AD pathogenesis and attributes to propose a new perspective on this pathology and deliberate over the primary limitations of key experimental models. Additionally, we discuss several fundamental problems that may explain the translational failures and suggest some possible directions for more effective preclinical studies.


Assuntos
Doença de Alzheimer , Camundongos , Animais , Humanos , Doença de Alzheimer/patologia , Pesquisa Translacional Biomédica , Reprodutibilidade dos Testes , Modelos Animais de Doenças , Camundongos Transgênicos , Peptídeos beta-Amiloides , Emaranhados Neurofibrilares/patologia
6.
Ageing Res Rev ; 96: 102270, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38484981

RESUMO

Among the central features of Alzheimer's disease (AD) progression are altered levels of the neuropeptide somatostatin (SST), and the colocalisation of SST-positive interneurons (SST-INs) with amyloid-ß plaques, leading to cell death. In this theoretical review, I propose a molecular model for the pathogenesis of AD based on SST-IN hypofunction and hyperactivity. Namely, hypofunctional and hyperactive SST-INs struggle to control hyperactivity in medial regions in early stages, leading to axonal Aß production through excessive presynaptic GABAB inhibition, GABAB1a/APP complex downregulation and internalisation. Concomitantly, excessive SST-14 release accumulates near SST-INs in the form of amyloids, which bind to Aß to form toxic mixed oligomers. This leads to differential SST-IN death through excitotoxicity, further disinhibition, SST deficits, and increased Aß release, fibrillation and plaque formation. Aß plaques, hyperactive networks and SST-IN distributions thereby tightly overlap in the brain. Conversely, chronic stimulation of postsynaptic SST2/4 on gulutamatergic neurons by hyperactive SST-INs promotes intense Mitogen-Activated Protein Kinase (MAPK) p38 activity, leading to somatodendritic p-tau staining and apoptosis/neurodegeneration - in agreement with a near complete overlap between p38 and neurofibrillary tangles. This model is suitable to explain some of the principal risk factors and markers of AD progression, including mitochondrial dysfunction, APOE4 genotype, sex-dependent vulnerability, overactive glial cells, dystrophic neurites, synaptic/spine losses, inter alia. Finally, the model can also shed light on qualitative aspects of AD neuropsychology, especially within the domains of spatial and declarative (episodic, semantic) memory, under an overlying pattern of contextual indiscrimination, ensemble instability, interference and generalisation.


Assuntos
Doença de Alzheimer , Humanos , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Somatostatina/metabolismo , Neurônios/metabolismo , Emaranhados Neurofibrilares/patologia
7.
Acta Neuropathol ; 147(1): 54, 2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38472443

RESUMO

Rare and common GBA variants are risk factors for both Parkinson's disease (PD) and dementia with Lewy bodies (DLB). However, the degree to which GBA variants are associated with neuropathological features in Lewy body disease (LBD) is unknown. Herein, we assessed 943 LBD cases and examined associations of 15 different neuropathological outcomes with common and rare GBA variants. Neuropathological outcomes included LBD subtype, presence of a high likelihood of clinical DLB (per consensus guidelines), LB counts in five cortical regions, tyrosine hydroxylase immunoreactivity in the dorsolateral and ventromedial putamen, ventrolateral substantia nigra neuronal loss, Braak neurofibrillary tangle (NFT) stage, Thal amyloid phase, phospho-ubiquitin (pS65-Ub) level, TDP-43 pathology, and vascular disease. Sequencing of GBA exons revealed a total of 42 different variants (4 common [MAF > 0.5%], 38 rare [MAF < 0.5%]) in our series, and 165 cases (17.5%) had a copy of the minor allele for ≥ 1 variant. In analysis of common variants, p.L483P was associated with a lower Braak NFT stage (OR = 0.10, P < 0.001). In gene-burden analysis, presence of the minor allele for any GBA variant was associated with increased odds of a high likelihood of DLB (OR = 2.00, P < 0.001), a lower Braak NFT stage (OR = 0.48, P < 0.001), a lower Thal amyloid phase (OR = 0.55, P < 0.001), and a lower pS65-Ub level (ß: -0.37, P < 0.001). Subgroup analysis revealed that GBA variants were most common in LBD cases with a combination of transitional/diffuse LBD and Braak NFT stage 0-II or Thal amyloid phase 0-1, and correspondingly that the aforementioned associations of GBA gene-burden with a decreased Braak NFT stage and Thal amyloid phase were observed only in transitional or diffuse LBD cases. Our results indicate that in LBD, GBA variants occur most frequently in cases with greater LB pathology and low AD pathology, further informing disease-risk associations of GBA in PD, PD dementia, and DLB.


Assuntos
Doença de Alzheimer , Doença por Corpos de Lewy , Doença de Parkinson , Humanos , Doença por Corpos de Lewy/patologia , Doença de Parkinson/patologia , Doença de Alzheimer/patologia , Substância Negra/patologia , Emaranhados Neurofibrilares/patologia
8.
Biomolecules ; 14(2)2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-38397402

RESUMO

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that is characterized by amyloid-beta (Aß) plaques and tau neurofibrillary tangles (NFT). Modelling aspects of AD is challenging due to its complex multifactorial etiology and pathology. The present study aims to establish a cost-effective and rapid method to model the two primary pathologies in organotypic brain slices. Coronal hippocampal brain slices (150 µm) were generated from postnatal (day 8-10) C57BL6 wild-type mice and cultured for 9 weeks. Collagen hydrogels containing either an empty load or a mixture of human Aß42 and P301S aggregated tau were applied to the slices. The media was further supplemented with various intracellular pathway modulators or heavy metals to augment the appearance of Aß plaques and tau NFTs, as assessed by immunohistochemistry. Immunoreactivity for Aß and tau was significantly increased in the ventral areas in slices with a mixture of human Aß42 and P301S aggregated tau compared to slices with empty hydrogels. Aß plaque- and tau NFT-like pathologies could be induced independently in slices. Heavy metals (aluminum, lead, cadmium) potently augmented Aß plaque-like pathology, which developed intracellularly prior to cell death. Intracellular pathway modulators (scopolamine, wortmannin, MHY1485) significantly boosted tau NFT-like pathologies. A combination of nanomolar concentrations of scopolamine, wortmannin, MHY1485, lead, and cadmium in the media strongly increased Aß plaque- and tau NFT-like immunoreactivity in ventral areas compared to the slices with non-supplemented media. The results highlight that we could harness the potential of the collagen hydrogel-based spreading of human Aß42 and P301S aggregated tau, along with pharmacological manipulation, to produce pathologies relevant to AD. The results offer a novel ex vivo organotypic slice model to investigate AD pathologies with potential applications for screening drugs or therapies in the future.


Assuntos
Doença de Alzheimer , Camundongos , Animais , Humanos , Doença de Alzheimer/metabolismo , Proteínas tau/metabolismo , Cádmio/metabolismo , Wortmanina/metabolismo , Camundongos Transgênicos , Peptídeos beta-Amiloides/metabolismo , Emaranhados Neurofibrilares/metabolismo , Emaranhados Neurofibrilares/patologia , Encéfalo/metabolismo , Placa Amiloide/complicações , Placa Amiloide/metabolismo , Placa Amiloide/patologia , Colágeno/metabolismo , Hidrogéis/metabolismo , Derivados da Escopolamina/metabolismo
9.
Nat Rev Neurol ; 20(4): 245-251, 2024 04.
Artigo em Inglês | MEDLINE | ID: mdl-38424454

RESUMO

Dementia, a prevalent condition among older individuals, has profound societal implications. Extensive research has resulted in no cure for what is perceived as the most common dementing illness: Alzheimer disease (AD). AD is defined by specific brain abnormalities - amyloid-ß plaques and tau protein neurofibrillary tangles - that are proposed to actively influence the neurodegenerative process. However, conclusive evidence of amyloid-ß toxicity is lacking, the mechanisms leading to the accumulation of plaques and tangles are unknown, and removing amyloid-ß has not halted neurodegeneration. So, the question remains, are we making progress towards a solution? The complexity of AD is underscored by numerous genetic and environmental risk factors, and diverse clinical presentations, suggesting that AD is more akin to a syndrome than to a traditional disease, with its pathological manifestation representing a convergence of pathogenic pathways. Therefore, a solution requires a multifaceted approach over a single 'silver bullet'. Improved recognition and classification of conditions that converge in plaques and tangle accumulation and their treatment requires the use of multiple strategies simultaneously.


Assuntos
Doença de Alzheimer , Humanos , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Emaranhados Neurofibrilares/metabolismo , Emaranhados Neurofibrilares/patologia
10.
J Prev Alzheimers Dis ; 11(2): 414-421, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38374747

RESUMO

In vivo Alzheimer's disease diagnosis and staging is traditionally based on clinical features. However, the agreement between clinical and pathological Alzheimer's disease diagnosis, whose diagnosis assessment includes amyloid and Braak histopathological tau staging, is not completely convergent. The development of positron emission tomography (PET) tracers targeting neurofibrillary tangles offers prospects for advancing the staging of Alzheimer's disease from both biological and clinical perspectives. Recent advances in radiochemistry made it possible to apply the postmortem Braak staging framework to tau-PET images obtained in vivo. Here, our aim is to provide a narrative review of the current literature on the relationship between Alzheimer's disease clinical features and the PET-based Braak staging framework. Overall, the available studies support the stepwise increase in disease severity following the advance of PET-based Braak stages, with later stages being associated with worse cognitive and clinical symptoms. In line with this, there is a trend for unimpaired cognition, mild cognitive impairment, and Alzheimer's disease dementia to be compatible with early, intermediate, and late patterns of tau deposition based on PET-based Braak stages. Moreover, neuropsychiatric symptom severity seems to be linked to the extent of tau-PET signal across Braak areas. In sum, this framework seems to correspond well with the clinical progression of Alzheimer's disease, which is an indication of its potential utility in research and clinical practice, especially for detecting preclinical tau levels in individuals without symptoms. However, further research is needed to improve the generalizability of these findings and to better understand the applications of this staging framework.


Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Humanos , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/patologia , Proteínas tau , Emaranhados Neurofibrilares/patologia , Tomografia por Emissão de Pósitrons/métodos , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/patologia
11.
Brain Res Bull ; 206: 110835, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38043648

RESUMO

The pathological features of Alzheimer's disease (AD), a progressive neurodegenerative disorder, include the deposition of extracellular amyloid beta (Aß) plaques and intracellular tau neurofibrillary tangles. A decline in cognitive ability is related to the accumulation of Aß in patients with AD. Autophagy, which is a primary intracellular mechanism for degrading aggregated proteins and damaged organelles, plays a crucial role in AD. In this review, we summarize the most recent research progress regarding the process of autophagy and the effect of autophagy on Aß. We further discuss some typical monomers of natural products that contribute to the clearance of Aß by autophagy, which can alleviate AD. This provides a new perspective for the application of autophagy modulation in natural product therapy for AD.


Assuntos
Doença de Alzheimer , Humanos , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Autofagia , Emaranhados Neurofibrilares/patologia , Neurônios/metabolismo , Proteínas tau/metabolismo
12.
Alzheimers Dement ; 20(2): 1468-1474, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37965965

RESUMO

INTRODUCTION: Anti-amyloid therapies are at the forefront of efforts to treat Alzheimer's disease (AD). Identifying amyloid risk factors may aid screening and intervention strategies. While veterans face increased exposure to risk factors, whether they face a greater neuropathologic amyloid burden is not well understood. METHODS: Male decedents donating to two Alzheimer's Disease Research Center (ADRC) brain banks from 1986 to 2018 with categorized neuritic plaque density and neurofibrillary tangles (n = 597) were included. Using generalized ordered logistic regression we modeled each outcome's association with military history adjusting for age and death year. RESULTS: Having served in the military (60% of sample) is associated with post mortem neuritic amyloid plaque (for each comparison of higher to lower C scores OR = 1.26; 95% confidence interval [CI] = 1.06-1.49) and tau pathology (B score OR = 1.10; 95% CI = 1.08-1.12). DISCUSSION: This is the first study, to our knowledge, finding increased levels of verified AD neuropathology in those with military service. Targeted veteran AD therapies is a pressing need.


Assuntos
Doença de Alzheimer , Masculino , Humanos , Doença de Alzheimer/patologia , Emaranhados Neurofibrilares/patologia , Autopsia , Encéfalo/patologia , Neuropatologia , Placa Amiloide/patologia
13.
Ageing Res Rev ; 93: 102134, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38008402

RESUMO

According to the facts and figures 2023stated that 6.7 million Americans over the age of 65 have Alzheimer's disease (AD). The scenario of AD has reached up to the maximum, of 4.1 million individuals, 2/3rd are female patients, and approximately 1 in 9 adults over the age of 65 have dementia with AD dementia. The fact that there are now no viable treatments for AD indicates that the underlying disease mechanisms are not fully understood. The progressive neurodegenerative disease, AD is characterized by amyloid plaques and neurofibrillary tangles (NFTs) of abnormally hyperphosphorylated tau protein and senile plaques (SPs), which are brought on by the buildup of amyloid beta (Aß). Numerous attempts have been made to produce compounds that interfere with these characteristics because of significant research efforts into the primary pathogenic hallmark of this disorder. Here, we summarize several research that highlights interesting therapy strategies and the neuroprotective effects of GLP-1, Sigma, and, AGE-RAGE receptors in pre-clinical and clinical AD models.


Assuntos
Doença de Alzheimer , Doenças Neurodegenerativas , Humanos , Feminino , Masculino , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Doenças Neurodegenerativas/metabolismo , Proteínas tau/metabolismo , Emaranhados Neurofibrilares/patologia , Placa Amiloide/metabolismo
14.
Geroscience ; 46(1): 71-85, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37646904

RESUMO

Alzheimer's disease (AD) is a progressive neurodegenerative disorder and is the most common cause of dementia. The pathogenesis of AD still remains unclear, including two main hypotheses: amyloid cascade and tau hyperphosphorylation. The hallmark neuropathological changes of AD are extracellular deposits of amyloid-ß (Aß) plaques and intracellular neurofibrillary tangles (NFTs). Endocytosis plays an important role in a number of cellular processes including communication with the extracellular environment, nutrient uptake, and signaling by the cell surface receptors. Based on the results of genetic and biochemical studies, there is a link between neuronal endosomal function and AD pathology. Taking this into account, we can state that in the results of previous research, endolysosomal abnormality is an important cause of neuronal lesions in the brain. Endocytosis is a central pathway involved in the regulation of the degradation of amyloidogenic components. The results of the studies suggest that a correlation between alteration in the endocytosis process and associated protein expression progresses AD. In this article, we discuss the current knowledge about endosomal abnormalities in AD.


Assuntos
Doença de Alzheimer , Humanos , Doença de Alzheimer/genética , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Peptídeos beta-Amiloides/metabolismo , Emaranhados Neurofibrilares/metabolismo , Emaranhados Neurofibrilares/patologia , Endocitose
15.
Cytoskeleton (Hoboken) ; 81(1): 30-34, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37638691

RESUMO

Tau was discovered in the mid 1970's as a microtubule-associated protein that stimulates tubulin polymerization, and subsequently was shown to be expressed primarily in neurons, where it is most concentrated in axons. Interest in tau rose by the late 1980's, when it was shown to be the principal subunit of the neurofibrillary tangles (NFTs) that accumulate in Alzheimer's disease (AD) brain, and achieved new heights by the late 1990's, when numerous tau mutations were found to be highly penetrant for AD-related disorders that also are associated with NFTs and came to be known as non-Alzheimer's tauopathies. The role of tau in neurodegeneration is far more complex than whatever effects on neurons may be caused by NFTs, however, and here we review our work on dysregulation of mTOR by tau in AD. mTOR is a protein kinase and master regulator of myriad aspects of cellular behavior. We have defined a complex signaling network whereby aberrant tau phosphorylation provoked by amyloid-ß oligomers (AßOs), the building blocks of the amyloid plaques that form in AD brain, cause post-mitotic neurons to re-enter the cell cycle, but to die eventually instead of dividing, which may account for most neuron death in AD. Remarkably, we found that this same neuronal signaling network also poisons a fundamental cell biological process that we discovered, nutrient-induced mitochondrial activation, or NiMA. Tau-dependent cell cycle re-entry and NiMA inhibition occur in cultured neurons within a few hours of exposure to AßOs, and thus may represent seminal processes in AD pathogenesis.


Assuntos
Doença de Alzheimer , Humanos , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Proteínas tau , Emaranhados Neurofibrilares/metabolismo , Emaranhados Neurofibrilares/patologia , Fosforilação , Serina-Treonina Quinases TOR/metabolismo
16.
Alzheimers Dement ; 20(2): 783-797, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37777848

RESUMO

INTRODUCTION: Alzheimer's disease (AD) and primary age-related tauopathy (PART) both harbor 3R/4R hyperphosphorylated-tau (p-tau)-positive neurofibrillary tangles (NFTs) but differ in the spatial p-tau development in the hippocampus. METHODS: Using Nanostring GeoMx Digital Spatial Profiling, we compared protein expression within hippocampal subregions in NFT-bearing and non-NFT-bearing neurons in AD (n = 7) and PART (n = 7) subjects. RESULTS: Proteomic measures of synaptic health were inversely correlated with the subregional p-tau burden in AD and PART, and there were numerous differences in proteins involved in proteostasis, amyloid beta (Aß) processing, inflammation, microglia, oxidative stress, and neuronal/synaptic health between AD and PART and between definite PART and possible PART. DISCUSSION: These results suggest subfield-specific proteome differences that may explain some of the differences in Aß and p-tau distribution and apparent pathogenicity. In addition, hippocampal neurons in possible PART may have more in common with AD than with definite PART, highlighting the importance of Aß in the pathologic process. HIGHLIGHTS: Synaptic health is inversely correlated with local p-tau burden. The proteome of NFT- and non-NFT-bearing neurons is influenced by the presence of Aß in the hippocampus. Neurons in possible PART cases share more proteomic similarities with neurons in ADNC than they do with neurons in definite PART cases.


Assuntos
Doença de Alzheimer , Tauopatias , Humanos , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Proteômica , Proteoma , Proteínas tau/metabolismo , Tauopatias/patologia , Emaranhados Neurofibrilares/patologia , Hipocampo/patologia
17.
Cytoskeleton (Hoboken) ; 81(1): 116-121, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-38126608

RESUMO

My journey with tau started when in 1974 for the first time I isolated neurofibrillary tangles of paired helical filaments (PHFs) from autopsied Alzheimer's disease (AD) brains and discovered that they were made up of a ~50-70 KDa protein on SDS-polyacrylamide gels. Subsequently my team discovered that this PHF protein and the microtubule-associated factor called tau were one and the same protein. However, we found that tau in neurofibrillary tangles/PHFs in AD brain was abnormally hyperphosphorylated, and unlike normal tau, which promoted the assembly of tubulin into microtubules, the AD-hyperphosphorylated tau inhibited microtubule assembly. These discoveries of tau pathology in AD opened a new and a major area of research on tau and on the molecular pathology of this major cause of dementia in middle- and old-age individuals. Tau pathology, which without fail is made up of the aggregated hyperphosphorylated state of the protein, is also the hallmark lesion of a family of around 20 related neurodegenerative diseases, called tauopathies. Currently, tau pathology is a major drug target for the treatment of AD and related tauopathies. Both active and passive tau immunization human clinical trials at various stages are underway. Initial results range from negative to partially promising. Future studies will reveal whether tau therapy alone or in combination with drugs targeting Aß and/or neurodegeneration will be required to achieve the most effective treatment for AD and related disorders.


Assuntos
Doença de Alzheimer , Tauopatias , Humanos , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Proteínas tau , Emaranhados Neurofibrilares/metabolismo , Emaranhados Neurofibrilares/patologia , Tauopatias/metabolismo , Tauopatias/patologia , Microtúbulos/metabolismo
18.
Acta Neuropathol Commun ; 11(1): 190, 2023 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-38037144

RESUMO

Extracellular amyloid-ß (Aß) plaques and intracellular aggregates of tau protein in form of neurofibrillary tangles (NFT) are pathological hallmarks of Alzheimer's disease (AD). The exact mechanism how these two protein aggregates interact in AD is still a matter of debate. Neuritic plaques (NP), a subset of Aß plaques containing dystrophic neurites (DN), are suggested to be unique to AD and might play a role in the interaction of Aß and tau. Quantifying NP and non-NP in postmortem brain specimens from patients with increasing severity of AD neuropathological changes (ADNC), we demonstrate that the total number of Aß plaques and NP increase, while the number of non-NP stagnates. Furthermore, investigating the correlation between NP and NFT, we identified unexpected brain region-specific differences when comparing cases with increasingly more severe ADNC. In neocortical regions NFT counts increase in parallel with NP counts during the progression of ADNC, while this correlation is not observed in hippocampus. These data support the notion that non-NP are transformed into NP during the progression of ADNC and indicate that NP might drive cortical NFT formation. Next, using spatial transcriptomics, we analyzed the gene expression profile of the microenvironment around non-NP and NP. We identified an upregulation of neuronal systems and Ca-dependent event pathways around NP compared to non-NP. We speculate that the upregulation of these transcripts may hint at a compensatory mechanism underlying NP formation. Our studies suggest that the transformation of non-NP to NP is a key event in ADNC progression and points to regenerative failure as a potential driving force of this process.


Assuntos
Doença de Alzheimer , Humanos , Doença de Alzheimer/patologia , Placa Amiloide/patologia , Proteínas tau/metabolismo , Emaranhados Neurofibrilares/patologia , Peptídeos beta-Amiloides/metabolismo , Hipocampo/patologia
19.
J Med Chem ; 66(24): 17026-17043, 2023 12 28.
Artigo em Inglês | MEDLINE | ID: mdl-38090813

RESUMO

Alzheimer's Disease (AD) is the most widespread form of dementia, with one of the pathological hallmarks being the formation of neurofibrillary tangles (NFTs). These tangles consist of phosphorylated Tau fragments. Asparagine endopeptidase (AEP) is a key Tau cleaving enzyme that generates aggregation-prone Tau fragments. Inhibition of AEP to reduce the level of toxic Tau fragment formation could represent a promising therapeutic strategy. Here, we report the first orthosteric, selective, orally bioavailable, and brain penetrant inhibitors with an irreversible binding mode. We outline the development of the series starting from reversible molecules and demonstrate the link between inhibition of AEP and reduction of Tau N368 fragment both in vitro and in vivo.


Assuntos
Doença de Alzheimer , Proteínas tau , Humanos , Proteínas tau/metabolismo , Doença de Alzheimer/metabolismo , Encéfalo/metabolismo , Emaranhados Neurofibrilares/metabolismo , Emaranhados Neurofibrilares/patologia , Fosforilação
20.
Acta Neuropathol Commun ; 11(1): 202, 2023 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-38110981

RESUMO

Machine learning (ML) has increasingly been used to assist and expand current practices in neuropathology. However, generating large imaging datasets with quality labels is challenging in fields which demand high levels of expertise. Further complicating matters is the often seen disagreement between experts in neuropathology-related tasks, both at the case level and at a more granular level. Neurofibrillary tangles (NFTs) are a hallmark pathological feature of Alzheimer disease, and are associated with disease progression which warrants further investigation and granular quantification at a scale not currently accessible in routine human assessment. In this work, we first provide a baseline of annotator/rater agreement for the tasks of Braak NFT staging between experts and NFT detection using both experts and novices in neuropathology. We use a whole-slide-image (WSI) cohort of neuropathology cases from Emory University Hospital immunohistochemically stained for Tau. We develop a workflow for gathering annotations of the early stage formation of NFTs (Pre-NFTs) and mature intracellular (iNFTs) and show ML models can be trained to learn annotator nuances for the task of NFT detection in WSIs. We utilize a model-assisted-labeling approach and demonstrate ML models can be used to aid in labeling large datasets efficiently. We also show these models can be used to extract case-level features, which predict Braak NFT stages comparable to expert human raters, and do so at scale. This study provides a generalizable workflow for various pathology and related fields, and also provides a technique for accomplishing a high-level neuropathology task with limited human annotations.


Assuntos
Doença de Alzheimer , Doenças Neurodegenerativas , Humanos , Emaranhados Neurofibrilares/patologia , Doenças Neurodegenerativas/patologia , Proteínas tau/metabolismo , Fluxo de Trabalho , Encéfalo/patologia , Doença de Alzheimer/patologia , Aprendizado de Máquina
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