%0 Journal Article %J J Alzheimers Dis %D 2023 %T Characterizing Limbic-Predominant Age-Related TDP-43 Encephalopathy Without Alzheimer's Disease and Lewy Body Dementia in the Oldest Old: A Case Series. %A Leiby, Anne-Marie C %A Scambray, Kiana A %A Nguyen, Hannah L %A Basith, Farheen %A Fakhraee, Shahrzad %A Melikyan, Zarui A %A Bukhari, Syed A %A Montine, Thomas J %A Corrada, Maria M %A Kawas, Claudia H %A Sajjadi, S Ahmad %K Aged %K Aged, 80 and over %K Alzheimer Disease %K DNA-Binding Proteins %K Humans %K Lewy Body Disease %K Syncope %K Tauopathies %K TDP-43 Proteinopathies %X

BACKGROUND: Limbic-predominant age-related TDP-43 encephalopathy neuropathologic change (LATE-NC) is a clinicopathological construct proposed to facilitate studying TDP-43 pathology in older individuals.

OBJECTIVE: Our aim was to describe clinical and cognitive characteristics of LATE-NC without Alzheimer's disease neuropathologic change (ADNC) and Lewy body (LB) and to compare this with ADNC and primary age related tauopathy (PART).

METHODS: In 364 autopsies of the oldest old of The 90+ Study, we identified those with LATE-NC without ADNC and LB. Control groups were participants with ADNC and PART.

RESULTS: Of 31% of participants who had LATE-NC, only 5 (1.4%) had LATE-NC without ADNC and LB, all of whom had tau. These participants had a gradual and progressive cognitive decline. Four (80%) had dementia at death, a rate that was higher than ADNC (50%) and PART (21.7%). Mean duration of cognitive impairment was twice as long in LATE-NC without ADNC and LB (6.2 years) compared to ADNC (2.9 years) and PART (3 years). LATE-NC without ADNC and LB group had a higher prevalence of syncope, depression, and extrapyramidal signs than the ADNC and PART groups.

CONCLUSIONS: Despite the high prevalence of LATE-NC, LATE-NC without ADNC and LB was rare in this large oldest-old cohort, highlighting the very high prevalence of multiple pathologic changes in the oldest old. Slowly progressive cognitive decline, ubiquitous memory impairment, history of syncope and depression, and extrapyramidal signs were prominent features among our LATE-NC without ADNC and LB group.

%B J Alzheimers Dis %V 96 %P 113-124 %8 2023 %G eng %N 1 %R 10.3233/JAD-230238 %0 Journal Article %J J Alzheimers Dis %D 2023 %T Cognitive and Neuropsychological Profiles in Alzheimer's Disease and Primary Age-Related Tauopathy and the Influence of Comorbid Neuropathologies. %A Walker, Jamie M %A Gonzales, Mitzi M %A Goette, William %A Farrell, Kurt %A White Iii, Charles L %A Crary, John F %A Richardson, Timothy E %K Alzheimer Disease %K Amyloid beta-Peptides %K Apolipoproteins E %K Cognition %K Executive Function %K Humans %K Tauopathies %X

BACKGROUND: Alzheimer's disease neuropathologic change (ADNC) is defined by the progression of both hyperphosphorylated-tau (p-tau) and amyloid-β (Aβ) and is the most common underlying cause of dementia worldwide. Primary age-related tauopathy (PART), an Aβ-negative tauopathy largely confined to the medial temporal lobe, is increasingly being recognized as an entity separate from ADNC with diverging clinical, genetic, neuroanatomic, and radiologic profiles.

OBJECTIVE: The specific clinical correlates of PART are largely unknown; we aimed to identify cognitive and neuropsychological differences between PART, ADNC, and subjects with no tauopathy (NT).

METHODS: We compared 2,884 subjects with autopsy-confirmed intermediate-high stage ADNC to 208 subjects with definite PART (Braak stage I-IV, Thal phase 0, CERAD NP score "absent") and 178 NT subjects from the National Alzheimer's Coordinating Center dataset.

RESULTS: PART subjects were older than either ADNC or NT patients. The ADNC cohort had more frequent neuropathological comorbidities as well as APOE ɛ4 alleles than the PART or NT cohort, and less frequent APOE ɛ2 alleles than either group. Clinically, ADNC patients performed significantly worse than NT or PART subjects across cognitive measures, but PART subjects had selective deficits in measures of processing speed, executive function, and visuospatial function, although additional cognitive measures were further impaired in the presence of neuropathologic comorbidities. In isolated cases of PART with Braak stage III-IV, there are additional deficits in measures of language.

CONCLUSION: Overall, these findings demonstrate underlying cognitive features specifically associated with PART, and reinforce the concept that PART is a distinct entity from ADNC.

%B J Alzheimers Dis %V 92 %P 1037-1049 %8 2023 %G eng %N 3 %R 10.3233/JAD-230022 %0 Journal Article %J J Alzheimers Dis %D 2021 %T NLRP3 Inflammasome: A Starring Role in Amyloid-β- and Tau-Driven Pathological Events in Alzheimer's Disease. %A Van Zeller, Mariana %A Dias, Diogo %A Sebastião, Ana M %A Valente, Cláudia A %K Alzheimer Disease %K Amyloid beta-Peptides %K Animals %K Astrocytes %K Humans %K Inflammasomes %K Inflammation %K Microglia %K NLR Family, Pyrin Domain-Containing 3 Protein %K Tauopathies %X

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease commonly diagnosed among the elderly population. AD is characterized by the loss of synaptic connections, neuronal death, and progressive cognitive impairment, attributed to the extracellular accumulation of senile plaques, composed by insoluble aggregates of amyloid-β (Aβ) peptides, and to the intraneuronal formation of neurofibrillary tangles shaped by hyperphosphorylated filaments of the microtubule-associated protein tau. However, evidence showed that chronic inflammatory responses, with long-lasting exacerbated release of proinflammatory cytokines by reactive glial cells, contribute to the pathophysiology of the disease. NLRP3 inflammasome (NLRP3), a cytosolic multiprotein complex sensor of a wide range of stimuli, was implicated in multiple neurological diseases, including AD. Herein, we review the most recent findings regarding the involvement of NLRP3 in the pathogenesis of AD. We address the mechanisms of NLRP3 priming and activation in glial cells by Aβ species and the potential role of neurofibrillary tangles and extracellular vesicles in disease progression. Neuronal death by NLRP3-mediated pyroptosis, driven by the interneuronal tau propagation, is also discussed. We present considerable evidence to claim that NLRP3 inhibition, is undoubtfully a potential therapeutic strategy for AD.

%B J Alzheimers Dis %V 83 %P 939-961 %8 2021 %G eng %N 3 %1 https://www.ncbi.nlm.nih.gov/pubmed/34366341?dopt=Abstract %R 10.3233/JAD-210268 %0 Journal Article %J J Alzheimers Dis %D 2018 %T In Vivo Visualization of Tau Accumulation, Microglial Activation, and Brain Atrophy in a Mouse Model of Tauopathy rTg4510. %A Ishikawa, Ai %A Tokunaga, Masaki %A Maeda, Jun %A Minamihisamatsu, Takeharu %A Shimojo, Masafumi %A Takuwa, Hiroyuki %A Ono, Maiko %A Ni, Ruiqing %A Hirano, Shigeki %A Kuwabara, Satoshi %A Ji, Bin %A Zhang, Ming-Rong %A Aoki, Ichio %A Suhara, Tetsuya %A Higuchi, Makoto %A Sahara, Naruhiko %K Animals %K Atrophy %K Benzothiazoles %K Brain %K Disease Models, Animal %K Female %K Magnetic Resonance Imaging %K Male %K Mice %K Mice, Transgenic %K Microglia %K Positron-Emission Tomography %K Receptors, GABA %K tau Proteins %K Tauopathies %X

BACKGROUND: Tau imaging using PET is a promising tool for the diagnosis and evaluation of tau-related neurodegenerative disorders, but the relationship among PET-detectable tau, neuroinflammation, and neurodegeneration is not yet fully understood.

OBJECTIVE: We aimed to elucidate sequential changes in tau accumulation, neuroinflammation, and brain atrophy by PET and MRI in a tauopathy mouse model.

METHODS: rTg4510 transgenic (tg) mice expressing P301L mutated tau and non-tg mice were examined with brain MRI and PET imaging (analyzed numbers: tg = 17, non-tg = 13; age 2.5∼14 months). As PET probes, [11C]PBB3 (Pyridinyl-Butadienyl-Benzothiazole 3) and [11C]AC-5216 were used to visualize tau pathology and 18-kDa translocator protein (TSPO) neuroinflammation. Tau pathology and microglia activation were subsequently analyzed by histochemistry.

RESULTS: PET studies revealed age-dependent increases in [11C]PBB3 and [11C]AC-5216 signals, which were correlated with age-dependent volume reduction in the forebrain on MRI. However, the increase in [11C]PBB3 signals reached a plateau at age 7 months, and therefore its significant correlation with [11C]AC-5216 disappeared after age 7 months. In contrast, [11C]AC-5216 showed a strong correlation with both age and volume reduction until age 14 months. Histochemical analyses confirmed the relevance of pathological tau accumulation and elevated TSPO immunoreactivity in putative microglia.

CONCLUSION: Our results showed that tau accumulation is associated with neuroinflammation and brain atrophy in a tauopathy mouse model. The time-course of the [11C]PBB3- and TSPO-PET finding suggests that tau deposition triggers progressive neuroinflammation, and the sequential changes can be evaluated in vivo in mouse brains.

%B J Alzheimers Dis %V 61 %P 1037-1052 %8 2018 %G eng %N 3 %1 http://www.ncbi.nlm.nih.gov/pubmed/29332041?dopt=Abstract %R 10.3233/JAD-170509 %0 Journal Article %J J Alzheimers Dis %D 2018 %T Increased Vulnerability of the Hippocampus in Transgenic Mice Overexpressing APP and Triple Repeat Tau. %A Arner, Andrew %A Rockenstein, Edward %A Mante, Michael %A Florio, Jazmin %A Masliah, Deborah %A Salehi, Bahar %A Adame, Anthony %A Overk, Cassia %A Masliah, Eliezer %A Rissman, Robert A %K Alzheimer Disease %K Amyloid beta-Peptides %K Animals %K Disease Models, Animal %K Female %K Glycogen Synthase Kinase 3 %K Hippocampus %K Humans %K Male %K Mice %K Mice, Transgenic %K Neocortex %K tau Proteins %K Tauopathies %X

Alzheimer's disease (AD) is the most common tauopathy, characterized by progressive accumulation of amyloid-β (Aβ) and hyperphosphorylated tau. While pathology associated with the 4-repeat (4R) tau isoform is more abundant in corticobasal degeneration and progressive supranuclear palsy, both 3R and 4R tau isoforms accumulate in AD. Many studies have investigated interactions between Aβ and 4R tau in double transgenic mice, but few, if any, have examined the effects of Aβ with 3R tau. To examine this relationship, we crossed our APP751 mutant line with our recently characterized 3R tau mutant model to create a bigenic line (hAPP-3RTau) to model AD neuropathology. Mice were analyzed at 3 and 6 months of age for pathological and behavioral endpoints. While both the 3RTau and the hAPP-3RTau mice showed neuronal loss, increased tau aggregation, Aβ plaques and exhibited more behavioral deficits compared to the non-tg control, the bigenic mice often displaying relatively worsening levels. We found that even in young animals we found that the presence of APP/Aβ increased the accumulation of 3R tau in the neocortex and hippocampus. This observation was accompanied by activation of GSK3 and neurodegeneration in the neocortex and CA1 region. These results suggest that in addition to 4R tau, APP/Aβ may also enhance accumulation of 3R tau, a process which may be directly relevant to pathogenic pathways in AD. Our results demonstrate that this bigenic model closely parallels the pathological course of AD and may serve as a valuable model for testing new pharmacological interventions.

%B J Alzheimers Dis %V 61 %P 1201-1219 %8 2018 %G eng %N 3 %1 http://www.ncbi.nlm.nih.gov/pubmed/29332037?dopt=Abstract %R 10.3233/JAD-170388 %0 Journal Article %J J Alzheimers Dis %D 2018 %T SIRT1 Deacetylates SC35 and Suppresses Its Function in Tau Exon 10 Inclusion. %A Yin, Xiaomin %A Jiang, Xiaosu %A Wang, Jia %A Qian, Shuo %A Liu, Fei %A Qian, Wei %K Alternative Splicing %K Alzheimer Disease %K Exons %K HEK293 Cells %K HeLa Cells %K Humans %K Phosphorylation %K Ribonucleoproteins %K Serine-Arginine Splicing Factors %K Sirtuin 1 %K tau Proteins %K Tauopathies %X

Approximately equal amounts of 3R-tau and 4R-tau resulting from alternative splicing of tau exon 10 is necessary to maintain normal brain function. Dysregulation of alternative splicing of tau exon 10 and the imbalance of 3R-tau/4R-tau have been seen in inherited and sporadic tauopathies. Splicing factor SC35 (also name as SRSF2) plays an important role in promoting tau exon 10 inclusion. SC35 is post-translationally modified by phosphorylation and acetylation, but the role of acetylation in SC35-medicated tau exon 10 inclusion is unknown. Sirtuin type 1 (SIRT1) is an enzyme that deacetylates proteins and associates with age-related disease such as Alzheimer's disease. In the present study, we determined the role of SIRT1 in SC35 acetylation and in the alternative splicing of tau exon 10. We found that SIRT1 interacts with and deacetylates SC35, and inhibits SC35-promoted tau exon 10 inclusion. Substituting K52 residue of SC35 by arginine impairs the role of SC35 in tau exon 10 inclusion. These results suggest that SIRT1 may serve as a therapeutic target for tauopathy by regulating SC35-mediated tau exon 10 splicing.

%B J Alzheimers Dis %V 61 %P 561-570 %8 2018 %G eng %N 2 %1 http://www.ncbi.nlm.nih.gov/pubmed/29226865?dopt=Abstract %R 10.3233/JAD-170418 %0 Journal Article %J J Alzheimers Dis %D 2018 %T Tauopathies: Mechanisms and Therapeutic Strategies. %A Tan, Chen-Chen %A Zhang, Xiao-Yan %A Tan, Lan %A Yu, Jin-Tai %K Animals %K Biomarkers %K Brain %K Disease Models, Animal %K Humans %K Neuroimaging %K Phosphorylation %K Positron-Emission Tomography %K tau Proteins %K Tauopathies %X

Tauopathies are morphologically, biochemically, and clinically heterogeneous neurodegenerative diseases defined by the accumulation of abnormal tau proteins in the brain. There is no effective method to prevent and reverse the tauopathies, but this gloomy picture has been changed by recent research advances. Evidences from genetic studies, experimental animal models, and molecular and cell biology have shed light on the main mechanisms of the diseases. The development of radiology and biochemistry, especially the development of PET imaging, will provide important biomarkers for the clinical diagnosis and treatment. Given the central role of tau in tauopathies, many treatments have constantly emerged, including targeting phosphorylation, targeting aggregation, increasing microtubule stabilization, tau immunization, clearance of tau, anti-inflammatory treatment, and other therapeutics. There is still a long way to go before we obtain drug therapy targeted at multifactor mechanisms.

%B J Alzheimers Dis %V 61 %P 487-508 %8 2018 %G eng %N 2 %1 http://www.ncbi.nlm.nih.gov/pubmed/29278892?dopt=Abstract %R 10.3233/JAD-170187 %0 Journal Article %J J Alzheimers Dis %D 2016 %T Hyperactivity with Agitative-Like Behavior in a Mouse Tauopathy Model. %A Jul, Pia %A Volbracht, Christiane %A de Jong, Inge E M %A Helboe, Lone %A Elvang, Anders Brandt %A Pedersen, Jan Torleif %K Age Factors %K Analysis of Variance %K Animals %K Brain %K Cognition Disorders %K Disease Models, Animal %K Doxycycline %K Exploratory Behavior %K Humans %K Hyperkinesis %K Male %K Maze Learning %K Mice %K Mice, Transgenic %K Motor Activity %K Mutation %K Psychomotor Agitation %K tau Proteins %K Tauopathies %K Time Factors %X

Tauopathies, such as Alzheimer's disease (AD) and frontotemporal dementia (FTD), are characterized by formation of neurofibrillary tangles consisting of hyperphosphorylated tau. In addition to memory loss, patients experience behavioral symptoms such as agitation, aggression, depression, and insomnia. We explored the behavioral phenotype of a mouse model (rTg4510) carrying the human tau P301L mutation found in a familial form of FTD. We tested these mice in locomotor activity assays as well as in the Morris water maze to access spatial memory. In addition to cognitive impairments, rTg4510 mice exhibited a hyperactivity phenotype which correlated with progression of tau pathology and was dependent on P301L tau transgene expression. The hyperactive phenotype was characterized by significantly increased locomotor activity in a novel and in a simulated home cage environment together with a disturbed day/night cycle. The P301L-tau-dependent hyperactivity and agitative-like phenotype suggests that these mice may form a correlate to some of the behavioral disturbances observed in advanced AD and FTD.

%B J Alzheimers Dis %V 49 %P 783-95 %8 2016 %G eng %N 3 %1 http://www.ncbi.nlm.nih.gov/pubmed/26519432?dopt=Abstract %R 10.3233/JAD-150292 %0 Journal Article %J Neuron %D 2012 %T Propagation of tau pathology in a model of early Alzheimer's disease. %A de Calignon, Alix %A Polydoro, Manuela %A Suárez-Calvet, Marc %A William, Christopher %A Adamowicz, David H %A Kopeikina, Kathy J %A Pitstick, Rose %A Sahara, Naruhiko %A Ashe, Karen H %A Carlson, George A %A Spires-Jones, Tara L %A Hyman, Bradley T %K Age Factors %K Alzheimer Disease %K Animals %K Disease Models, Animal %K Disease Progression %K Entorhinal Cortex %K Epitopes %K Gene Expression Regulation %K Glial Fibrillary Acidic Protein %K Gliosis %K Hippocampus %K Humans %K Mice %K Mice, Inbred C57BL %K Mice, Transgenic %K Mutation %K Nerve Degeneration %K Neurofibrillary Tangles %K Neurons %K RNA, Messenger %K Serine %K tau Proteins %K Tauopathies %X

Neurofibrillary tangles advance from layer II of the entorhinal cortex (EC-II) toward limbic and association cortices as Alzheimer's disease evolves. However, the mechanism involved in this hierarchical pattern of disease progression is unknown. We describe a transgenic mouse model in which overexpression of human tau P301L is restricted to EC-II. Tau pathology progresses from EC transgene-expressing neurons to neurons without detectable transgene expression, first to EC neighboring cells, followed by propagation to neurons downstream in the synaptic circuit such as the dentate gyrus, CA fields of the hippocampus, and cingulate cortex. Human tau protein spreads to these regions and coaggregates with endogenous mouse tau. With age, synaptic degeneration occurs in the entorhinal target zone and EC neurons are lost. These data suggest that a sequence of progressive misfolding of tau proteins, circuit-based transfer to new cell populations, and deafferentation induced degeneration are part of a process of tau-induced neurodegeneration.

%B Neuron %V 73 %P 685-97 %8 2012 Feb 23 %G eng %N 4 %1 http://www.ncbi.nlm.nih.gov/pubmed/22365544?dopt=Abstract %R 10.1016/j.neuron.2011.11.033 %0 Journal Article %J Curr Alzheimer Res %D 2010 %T Tau in Alzheimer disease and related tauopathies. %A Iqbal, K %A Liu, F %A Gong, C-X %A Grundke-Iqbal, I %K Alzheimer Disease %K Animals %K Humans %K Phosphorylation %K tau Proteins %K Tauopathies %X

Tau is the major microtubule associated protein (MAP) of a mature neuron. The other two neuronal MAPs are MAP1 and MAP2. An established function of MAPs is their interaction with tubulin and promotion of its assembly into microtubules and stabilization of the microtubule network. The microtubule assembly promoting activity of tau, a phosphoprotein, is regulated by its degree of phosphorylation. Normal adult human brain tau contains 2-3 moles phosphate/mole of tau protein. Hyperphosphorylation of tau depresses this biological activity of tau. In Alzheimer disease (AD) brain tau is ~three to four-fold more hyperphosphorylated than the normal adult brain tau and in this hyperphosphorylated state it is polymerized into paired helical filaments ([PHF) admixed with straight filaments (SF) forming neurofibrillary tangles. Tau is transiently hyperphosphorylated during development and during anesthesia and hypothermia but not to the same state as in AD brain. The abnormally hyperphosphorylated tau in AD brain is distinguished from transiently hyperphosphorylated tau by its ability (1) to sequester normal tau, MAP1 and MAP2 and disrupt microtubules, and (2) to self-assemble into PHF/SF. The cytosolic abnormally hyperphosphorylated tau, because of oligomerization, unlike normal tau, is sedimentable and on self-assembly into PHF/SF, loses its ability to sequester normal MAPs. Some of the tau in AD brain is truncated which also promotes its self-assembly. Tau mutations found in frontotemporal dementia apparently promote its abnormal hyperphosphorylation. Thus, the AD abnormally hyperphosphorylated tau (1) is distinguishable from both normal and transiently hyperphosphorylated taus, and (2) is inhibitory when in a cytosolic/oligomeric state but not when it is self-assembled into PHF/SF. Inhibition of abnormal hyperphosphorylation of tau offers a promising therapeutic target for AD and related tauopathies.

%B Curr Alzheimer Res %V 7 %P 656-64 %8 2010 Dec %G eng %N 8 %1 http://www.ncbi.nlm.nih.gov/pubmed/20678074?dopt=Abstract