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Yasuno F, Minami H. Significant effects of cholinesterase inhibitors on tau pathology in the Alzheimer's disease continuum: An in vivo positron emission tomography study. Int J Geriatr Psychiatry 2021; 36:1274-1283. [PMID: 33594726 DOI: 10.1002/gps.5522] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 02/14/2021] [Indexed: 11/09/2022]
Abstract
OBJECTIVES No prior study has assessed the effects of cholinesterase inhibitors (ChEIs) on tau pathology in the brains of patients with Alzheimer's disease (AD). Using positron emission tomography, this study aimed to investigate whether ChEIs reduce tau aggregation in amyloid-positive participants. METHODS We analyzed datasets from the Alzheimer's Disease Neuroimaging Initiative and included amyloid-positive participants who had undergone baseline and 1- or 2-year follow-up AV-1451 positron emission tomography scans. We included participants treated with and without ChEIs (ChEIs group: n = 15, No-ChEIs group, n = 45). The annual change in tau aggregation was calculated as the difference in AV-1451- standardized uptake value ratio (SUVR) between the two scans divided by the time between scans. Group differences in annual AV-1451-SUVR change were examined. RESULTS We found a significantly lower annual change in AV-1451-SUVR in the Braak 1/2 regions (entorhinal cortex and hippocampus) of participants taking ChEIs. Increased AV-1451-SUVR between the first and second examinations were observed in 22 of 45 participants not taking ChEIs and 2 of 15 participants taking ChEIs. Fisher's exact test showed a significant difference in the ratio of participants with increased AV-1451-SUVR between the groups. CONCLUSIONS The findings of this positron emission tomography study suggest that the administration of ChEIs has some neuroprotective effects in patients of the AD continuum, at least in the early stage of the disease progression. This in vivo effect may be mediated via tau, preventing amyloid β-induced neurotoxicity.
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Affiliation(s)
- Fumihiko Yasuno
- National Hospital for Geriatric Medicine, National Center for Geriatrics and Gerontology, Obu, Japan
| | - Hiroyuki Minami
- National Hospital for Geriatric Medicine, National Center for Geriatrics and Gerontology, Obu, Japan
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Espinosa-Oliva AM, García-Revilla J, Alonso-Bellido IM, Burguillos MA. Brainiac Caspases: Beyond the Wall of Apoptosis. Front Cell Neurosci 2019; 13:500. [PMID: 31749689 PMCID: PMC6848387 DOI: 10.3389/fncel.2019.00500] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 10/22/2019] [Indexed: 01/04/2023] Open
Abstract
For the last two decades, caspases, a family of cysteine-aspartic proteases, have evolved from being considered solely as regulators of apoptosis or inflammation to having a wider range of functions. In this mini review, we focus on the most recent “non-apoptotic” roles of caspases in the CNS, particularly in neurons, astrocytes and oligodendrocytes. Non-apoptotic caspase functions in microglia have already been reviewed extensively elsewhere. Here we discuss the involvement of caspases in the activation of the inflammasome, autophagy, and non-apoptotic forms of cell death such as necroptosis and pyroptosis. Also, we review the involvement of caspases in synapses and the processing of aggregates key to neurodegenerative diseases such as Parkinson’s, Alzheimer’s and Huntington’s diseases. Likewise, we mention the recently described involvement of caspases in mitochondrial biogenesis, which is a function independent of the enzymatic activity. We conclude discussing the relevance that “new” functions of caspases have in the CNS and the future of this field of research.
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Affiliation(s)
- Ana María Espinosa-Oliva
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, and Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC, Seville, Spain
| | - Juan García-Revilla
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, and Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC, Seville, Spain
| | - Isabel María Alonso-Bellido
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, and Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC, Seville, Spain
| | - Miguel Angel Burguillos
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, and Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC, Seville, Spain
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The Ambiguous Relationship of Oxidative Stress, Tau Hyperphosphorylation, and Autophagy Dysfunction in Alzheimer's Disease. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2015:352723. [PMID: 26171115 PMCID: PMC4485995 DOI: 10.1155/2015/352723] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 03/02/2015] [Accepted: 03/03/2015] [Indexed: 12/30/2022]
Abstract
Alzheimer's disease (AD) is the most common form of dementia. The pathological hallmarks of AD are amyloid plaques [aggregates of amyloid-beta (Aβ)] and neurofibrillary tangles (aggregates of tau). Growing evidence suggests that tau accumulation is pathologically more relevant to the development of neurodegeneration and cognitive decline in AD patients than Aβ plaques. Oxidative stress is a prominent early event in the pathogenesis of AD and is therefore believed to contribute to tau hyperphosphorylation. Several studies have shown that the autophagic pathway in neurons is important under physiological and pathological conditions. Therefore, this pathway plays a crucial role for the degradation of endogenous soluble tau. However, the relationship between oxidative stress, tau protein hyperphosphorylation, autophagy dysregulation, and neuronal cell death in AD remains unclear. Here, we review the latest progress in AD, with a special emphasis on oxidative stress, tau hyperphosphorylation, and autophagy. We also discuss the relationship of these three factors in AD.
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Gray NE, Morré J, Kelley J, Maier CS, Stevens JF, Quinn JF, Soumyanath A. Caffeoylquinic acids in Centella asiatica protect against amyloid-β toxicity. J Alzheimers Dis 2015; 40:359-73. [PMID: 24448790 DOI: 10.3233/jad-131913] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The accumulation of amyloid-β (Aβ) is a hallmark of Alzheimer's disease and is known to result in neurotoxicity both in vivo and in vitro. We previously demonstrated that treatment with the water extract of Centella asiatica (CAW) improves learning and memory deficits in Tg2576 mice, an animal model of Aβ accumulation. However the active compounds in CAW remain unknown. Here we used two in vitro models of Aβ toxicity to confirm this neuroprotective effect and identify several active constituents of the CAW extract. CAW reduced Aβ-induced cell death and attenuated Aβ-induced changes in tau expression and phosphorylation in both the MC65 and SH-SY5Y neuroblastoma cell lines. We confirmed and quantified the presence of several mono- and dicaffeoylquinic acids (CQAs) in CAW using chromatographic separation coupled to mass spectrometry and ultraviolet spectroscopy. Multiple dicaffeoylquinic acids showed efficacy in protecting MC65 cells against Aβ-induced cytotoxicity. Isochlorogenic acid A and 1,5-dicaffeoylquinic acid were found to be the most abundant CQAs in CAW, and the most active in protecting MC65 cells from Aβ-induced cell death. Both compounds showed neuroprotective activity in MC65 and SH-SY5Y cells at concentrations comparable to their levels in CAW. Each compound not only mitigated Aβ-induced cell death, but was able to attenuate Aβ-induced alterations in tau expression and phosphorylation in both cell lines, as seen with CAW. These data suggest that CQAs are active neuroprotective components in CAW, and therefore are important markers for future studies on CAW standardization, bioavailability, and dosing.
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Affiliation(s)
- Nora E Gray
- Department of Neurology, Oregon Health and Science University, Portland, OR, USA
| | - Jeff Morré
- Department of Chemistry, Oregon State University, Corvallis, OR, USA
| | - Jeremiah Kelley
- Department of Chemistry, Oregon State University, Corvallis, OR, USA
| | - Claudia S Maier
- Department of Chemistry, Oregon State University, Corvallis, OR, USA
| | - Jan F Stevens
- Department of Pharmaceutical Sciences and the Linus Pauling Institute, Oregon State University, Corvallis, OR, USA
| | - Joseph F Quinn
- Department of Neurology, Oregon Health and Science University, Portland, OR, USA Department of Neurology and Parkinson's Disease Research Education and Clinical Care Center (PADRECC), Portland Veterans Affairs Medical Center, Portland, OR, USA
| | - Amala Soumyanath
- Department of Neurology, Oregon Health and Science University, Portland, OR, USA
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Cytoplasmic SET induces tau hyperphosphorylation through a decrease of methylated phosphatase 2A. BMC Neurosci 2014; 15:82. [PMID: 24981783 PMCID: PMC4086270 DOI: 10.1186/1471-2202-15-82] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 06/25/2014] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND The neuronal cytoplasmic localization of SET, an inhibitor of the phosphatase 2A (PP2A), results in tau hyperphosphorylation in the brains of Alzheimer patients through mechanisms that are still not well defined. RESULTS We used primary neurons and mouse brain slices to show that SET is translocated to the cytoplasm in a manner independent of both its cleavage and over-expression. The localization of SET in the cytoplasm, either by the translocation of endogenous SET or by internalization of the recombinant full-length SET protein, induced tau hyperphosphorylation. Cytoplasmic recombinant full-length SET in mouse brain slices induced a decrease of PP2A activity through a decrease of methylated PP2A levels. The levels of methylated PP2A were negatively correlated with tau hyperphosphorylation at Ser-202 but not with the abnormal phosphorylation of tau at Ser-422. CONCLUSIONS The presence of full-length SET in the neuronal cytoplasm is sufficient to impair PP2A methylation and activity, leading to tau hyperphosphorylation. In addition, our data suggest that tau hyperphosphorylation is regulated by different mechanisms at distinct sites. The translocation of SET to the neuronal cytoplasm, the low activity of PP2A, and tau hyperphosphorylation are associated in the brains of Alzheimer patients. Our data show a link between the translocation of SET in the cytoplasm and the decrease of methylated PP2A levels leading to a decrease of PP2A activity and tau hyperphosphorylation. This chain of events may contribute to the pathogenesis of Alzheimer disease.
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New Treatment for Alzheimer's Disease, Kamikihito, Reverses Amyloid-β-Induced Progression of Tau Phosphorylation and Axonal Atrophy. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2014; 2014:706487. [PMID: 24707311 PMCID: PMC3953424 DOI: 10.1155/2014/706487] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 01/11/2014] [Indexed: 11/17/2022]
Abstract
Aims. We previously reported that kamikihito (KKT), a traditional Japanese medicine, improved memory impairment and reversed the degeneration of axons in the 5XFAD mouse model of Alzheimer's disease (AD). However, the mechanism underlying the effects of KKT remained unknown. The aim of the present study was to investigate the mechanism by which KKT reverses the progression of axonal degeneration. Methods. Primary cultured cortical neurons were treated with amyloid beta (A β ) fragment comprising amino acid residues (25-35) (10 μ M) in an in vitro AD model. KKT (10 μ g/mL) was administered to the cells before or after A β treatment. The effects of KKT on A β -induced tau phosphorylation, axonal atrophy, and protein phosphatase 2A (PP2A) activity were investigated. We also performed an in vivo assay in which KKT (500 mg/kg/day) was administered to 5XFAD mice once a day for 15 days. Cerebral cortex homogenates were used to measure PP2A activity. Results. KKT improved A β -induced tau phosphorylation and axonal atrophy after they had already progressed. In addition, KKT increased PP2A activity in vitro and in vivo. Conclusions. KKT reversed the progression of A β -induced axonal degeneration. KKT reversed axonal degeneration at least in part through its role as an exogenous PP2A stimulator.
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Facchinetti P, Dorard E, Contremoulins V, Gaillard MC, Déglon N, Sazdovitch V, Guihenneuc-Jouyaux C, Brouillet E, Duyckaerts C, Allinquant B. SET translocation is associated with increase in caspase cleaved amyloid precursor protein in CA1 of Alzheimer and Down syndrome patients. Neurobiol Aging 2013; 35:958-68. [PMID: 24262202 DOI: 10.1016/j.neurobiolaging.2013.08.039] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 08/26/2013] [Accepted: 08/31/2013] [Indexed: 11/30/2022]
Abstract
Caspase cleaved amyloid precursor protein (APPcc) and SET are increased and mislocalized in the neuronal cytoplasm in Alzheimer Disease (AD) brains. Translocated SET to the cytoplasm can induce tau hyperphosphorylation. To elucidate the putative relationships between mislocalized APPcc and SET, we studied their level and distribution in the hippocampus of 5 controls, 3 Down syndrome and 10 Alzheimer patients. In Down syndrome and Alzheimer patients, APPcc and SET levels were increased in CA1 and the frequency of both localizations in the neuronal cytoplasm was high in CA1, and low in CA4. As the increase of APPcc is already present at early stages of AD, we overexpressed APPcc in CA1 and the dentate gyrus neurons of adult mice with a lentiviral construct. APPcc overexpression in CA1 and not in the dentate gyrus induced endogenous SET translocation and tau hyperphosphorylation. These data suggest that increase in APPcc in CA1 neurons could be an early event leading to the translocation of SET and the progression of AD through tau hyperphosphorylation.
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Affiliation(s)
- Patricia Facchinetti
- INSERM UMR 894, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Paris, France
| | - Emilie Dorard
- INSERM UMR 894, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Paris, France
| | - Vincent Contremoulins
- ImagoSeine, Institut Jacques Monod, UMR 7592, CNRS and Université Paris Diderot, Paris, France
| | | | | | - Véronique Sazdovitch
- Laboratoire de Neuropathologie Escourolle, Hôpital de la Salpêtrière, AP-HP, and Centre de Recherche de l'ICM (UPMC, INSERM UMR S 975, CNRS UMR 7225), Paris, France
| | - Chantal Guihenneuc-Jouyaux
- EA 4064, Université Paris Descartes, Sorbonne Paris Cité, Faculté des Sciences Pharmaceutiques et Biologiques, Paris, France
| | | | - Charles Duyckaerts
- Laboratoire de Neuropathologie Escourolle, Hôpital de la Salpêtrière, AP-HP, and Centre de Recherche de l'ICM (UPMC, INSERM UMR S 975, CNRS UMR 7225), Paris, France
| | - Bernadette Allinquant
- INSERM UMR 894, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Paris, France.
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Jung HJ, Kim YJ, Eggert S, Chung KC, Choi KS, Park SA. Age-dependent increases in tau phosphorylation in the brains of type 2 diabetic rats correlate with a reduced expression of p62. Exp Neurol 2013; 248:441-50. [PMID: 23906983 DOI: 10.1016/j.expneurol.2013.07.013] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 07/18/2013] [Accepted: 07/24/2013] [Indexed: 01/01/2023]
Abstract
Aging increases the co-incidence of Alzheimer's disease (AD) and type 2 diabetes (T2DM). However, the critical factors that contribute to the age-related increase in AD-T2DM comorbidity have yet to be clarified. In this study, aging effects and their relationship to AD-related pathology and T2DM as well as the underlying mechanisms of this process were investigated using obese rats with chronic T2DM. Tau pathology and its associated signaling pathways in the brain were compared between Otsuka Long-Evans Tokushima Fatty (OLETF) rats and corresponding non-diabetic controls at various ages. Tau phosphorylation at AD-related epitopes, including Thr212, Thr231, Ser262, and Ser396, increased with age in the soluble brain extracts of chronic OLETF rats and were accompanied by synaptic protein loss. There was also a marked age-dependent accumulation of polyubiquitinated substances in diabetic rats. Accordingly, tau proteins were highly polyubiquitinated in aged OLETF rats and a strong degree of co-localization existed between p-tau and ubiquitin in these neurons. In addition, the mRNA and protein levels of p62, a known cargo molecule that transports polyubiquitinated tau to proteasomal and autophagic degradation systems, decreased robustly with age in OLETF rats and there was an inverse correlation between protein levels of p62 and p-tau. The impaired degradation of polyubiquitinated p-tau due to age- and T2DM-dependent decreases in p62 transcription is a primary mechanism underlying increased AD-like pathology in a T2DM rat model as age increases. These results provide novel insight into the mechanisms supporting the age-related increase in AD-T2DM comorbidity.
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Affiliation(s)
- Hyun-Jung Jung
- Department of Neurology, Soonchunhyang University Bucheon Hospital, Bucheon 420-767, Republic of Korea
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Noh MY, Koh SH, Kim SM, Maurice T, Ku SK, Kim SH. Neuroprotective effects of donepezil against Aβ42-induced neuronal toxicity are mediated through not only enhancing PP2A activity but also regulating GSK-3β and nAChRs activity. J Neurochem 2013; 127:562-74. [PMID: 23711227 DOI: 10.1111/jnc.12319] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 05/02/2013] [Accepted: 05/06/2013] [Indexed: 11/28/2022]
Abstract
The main purpose of this study was to evaluate whether donepezil, acetylcholinesterase inhibitor, shown to play a protective role through inhibiting glycogen synthesis kinase-3β (GSK-3β) activity, could also exert neuroprotective effects by stimulating protein phosphatase 2A (PP2A) activity in the amyloid-beta (Aβ)42-induced neuronal toxicity model of Alzheimer's disease. In Aβ42-induced toxic conditions, each PP2A and GSK-3β activity measured at different times showed time-dependent reverse pattern toward the direction of accelerating neuronal deaths with the passage of time. In addition, donepezil pre-treatment showed dose-dependent stepwise increase of neuronal viability and stimulation of PP2A activity. However, such effects on them were significantly reduced through the depletion of PP2A activity with either okadaic acid or PP2Ac siRNA. In spite of blocked PP2A activity in this Aβ42 insult, however, donepezil pretreatment showed additional significant recovering effect on neuronal viability when compared to the value without donepezil. Moreover, donepezil partially recovered its dephosphorylating effect on hyperphosphorylated tau induced by Aβ42. This observation led us to assume that additional mechanisms of donepezil, including its inhibitory effect on GSK-3β activity and/or the activation role of nicotinic acetylcholine receptors (nAChRs), might be involved. Taken together, our results suggest that the neuroprotective effects of donepezil against Aβ42-induced neurotoxicity are mediated through activation of PP2A, but its additional mechanisms including regulation of GSK-3β and nAChRs activity would partially contribute to its effects. We investigated neuroprotective mechanisms of donepezil against Aβ42 toxicity: Donepezil increased neuronal viability with reduced p-tau by enhancing PP2A activity. Despite of blocked PP2A activity, donepezil showed additional recovering effect on neuronal viability, which findings led us to assume that additional mechanisms of donepezil including its inhibitory effect on GSK-3β activity and activating role of nicotinic AChRs might be involved.
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Affiliation(s)
- Min-Young Noh
- Department of Neurology, College of Medicine, Hanyang University, Seoul, Republic of Korea
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