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Theofilas P, Wang C, Butler D, Morales DO, Petersen C, Ambrose A, Chin B, Yang T, Khan S, Ng R, Kayed R, Karch CM, Miller BL, Gestwicki JE, Gan L, Temple S, Arkin MR, Grinberg LT. iPSC-induced neurons with the V337M MAPT mutation are selectively vulnerable to caspase-mediated cleavage of tau and apoptotic cell death. Mol Cell Neurosci 2024; 130:103954. [PMID: 39032719 DOI: 10.1016/j.mcn.2024.103954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 07/09/2024] [Accepted: 07/10/2024] [Indexed: 07/23/2024] Open
Abstract
BACKGROUND Tau post-translational modifications (PTMs) result in the gradual build-up of abnormal tau and neuronal degeneration in tauopathies, encompassing variants of frontotemporal lobar degeneration (FTLD) and Alzheimer's disease (AD). Tau proteolytically cleaved by active caspases, including caspase-6, may be neurotoxic and prone to self-aggregation. Also, our recent findings show that caspase-6 truncated tau represents a frequent and understudied aspect of tau pathology in AD in addition to phospho-tau pathology. In AD and Pick's disease, a large percentage of caspase-6 associated cleaved-tau positive neurons lack phospho-tau, suggesting that many vulnerable neurons to tau pathology go undetected when using conventional phospho-tau antibodies and possibly will not respond to phospho-tau based therapies. Therefore, therapeutic strategies against caspase cleaved-tau pathology could be necessary to modulate the extent of tau abnormalities in AD and other tauopathies. METHODS To understand the timing and progression of caspase activation, tau cleavage, and neuronal death, we created two mAbs targeting caspase-6 tau cleavage sites and probed postmortem brain tissue from an individual with FTLD due to the V337M MAPT mutation. We then assessed tau cleavage and apoptotic stress response in cortical neurons derived from induced pluripotent stem cells (iPSCs) carrying the FTD-related V337M MAPT mutation. Finally, we evaluated the neuroprotective effects of caspase inhibitors in these iPSC-derived neurons. RESULTS FTLD V337M MAPT postmortem brain showed positivity for both cleaved tau mAbs and active caspase-6. Relative to isogenic wild-type MAPT controls, V337M MAPT neurons cultured for 3 months post-differentiation showed a time-dependent increase in pathogenic tau in the form of caspase-cleaved tau, phospho-tau, and higher levels of tau oligomers. Accumulation of toxic tau species in V337M MAPT neurons was correlated with increased vulnerability to pro-apoptotic stress. Notably, this mutation-associated cell death was pharmacologically rescued by the inhibition of effector caspases. CONCLUSIONS Our results suggest an upstream, time-dependent accumulation of caspase-6 cleaved tau in V337M MAPT neurons promoting neurotoxicity. These processes can be reversed by caspase inhibition. These results underscore the potential of developing caspase-6 inhibitors as therapeutic agents for FTLD and other tauopathies. Additionally, they highlight the promise of using caspase-cleaved tau as biomarkers for these conditions.
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Affiliation(s)
- Panos Theofilas
- Memory and Aging Center, Department of Neurology, UCSF, San Francisco, CA, USA
| | - Chao Wang
- Gladstone Institute of Neurological Disease, San Francisco, CA, USA
| | | | - Dulce O Morales
- Memory and Aging Center, Department of Neurology, UCSF, San Francisco, CA, USA
| | - Cathrine Petersen
- Memory and Aging Center, Department of Neurology, UCSF, San Francisco, CA, USA
| | - Andrew Ambrose
- Department of Pharmaceutical Chemistry and Small Molecule Discovery Center, UCSF, San Francisco, CA, USA
| | | | | | - Shireen Khan
- ChemPartner San Francisco, South San Francisco, CA, USA
| | - Raymond Ng
- ChemPartner San Francisco, South San Francisco, CA, USA
| | - Rakez Kayed
- Department of Neurology, University of Texas Medical Branch, Galveston, TX, USA
| | | | - Bruce L Miller
- Memory and Aging Center, Department of Neurology, UCSF, San Francisco, CA, USA
| | - Jason E Gestwicki
- Department of Pharmaceutical Chemistry, UCSF, San Francisco, CA, USA
| | - Li Gan
- Gladstone Institute of Neurological Disease, San Francisco, CA, USA; Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | | | - Michelle R Arkin
- Department of Pharmaceutical Chemistry and Small Molecule Discovery Center, UCSF, San Francisco, CA, USA.
| | - Lea T Grinberg
- Memory and Aging Center, Department of Neurology, UCSF, San Francisco, CA, USA; Department of Pathology, University of Sao Paulo Medical School, Brazil.
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2
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Rizzi L, Grinberg LT. Exploring the significance of caspase-cleaved tau in tauopathies and as a complementary pathology to phospho-tau in Alzheimer's disease: implications for biomarker development and therapeutic targeting. Acta Neuropathol Commun 2024; 12:36. [PMID: 38419122 PMCID: PMC10900669 DOI: 10.1186/s40478-024-01744-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 02/12/2024] [Indexed: 03/02/2024] Open
Abstract
Tauopathies are neurodegenerative diseases that typically require postmortem examination for a definitive diagnosis. Detecting neurotoxic tau fragments in cerebrospinal fluid (CSF) and serum provides an opportunity for in vivo diagnosis and disease monitoring. Current assays primarily focus on total tau or phospho-tau, overlooking other post-translational modifications (PTMs). Caspase-cleaved tau is a significant component of AD neuropathological lesions, and experimental studies confirm the high neurotoxicity of these tau species. Recent evidence indicates that certain caspase-cleaved tau species, such as D13 and D402, are abundant in AD brain neurons and only show a modest degree of co-occurrence with phospho-tau, meaning caspase-truncated tau pathology is partially distinct and complementary to phospho-tau pathology. Furthermore, these caspase-cleaved tau species are nearly absent in 4-repeat tauopathies. In this review, we will discuss the significance of caspase-cleaved tau in the development of tauopathies, specifically emphasizing its role in AD. In addition, we will explore the potential of caspase-cleaved tau as a biomarker and the advantages for drug development targeting caspase-6. Developing specific and sensitive assays for caspase-cleaved tau in biofluids holds promise for improving the diagnosis and monitoring of tauopathies, providing valuable insights into disease progression and treatment efficacy.
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Affiliation(s)
- Liara Rizzi
- Memory and Aging Center, Department of Neurology, Sandler Neurosciences Center, University of California San Francisco, 675 Nelson Rising Lane, San Francisco, CA, 94158, USA
- Department of Neurology, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Lea T Grinberg
- Memory and Aging Center, Department of Neurology, Sandler Neurosciences Center, University of California San Francisco, 675 Nelson Rising Lane, San Francisco, CA, 94158, USA.
- Department of Pathology, LIM-22, University of São Paulo Medical School, São Paulo, SP, Brazil.
- Department of Pathology, University of California San Francisco, San Francisco, CA, USA.
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3
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Jobin B, Boller B, Frasnelli J. Smaller grey matter volume in the central olfactory system in mild cognitive impairment. Exp Gerontol 2023; 183:112325. [PMID: 37952649 DOI: 10.1016/j.exger.2023.112325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 11/02/2023] [Accepted: 11/07/2023] [Indexed: 11/14/2023]
Abstract
One of the major challenges in the diagnosis of Alzheimer's disease (AD) is to increase the specificity of the early diagnosis. While episodic memory impairment is a sensitive AD marker, other measures are needed to improve diagnostic specificity. A promising biomarker might be a cerebral atrophy of the central olfactory processing areas in the early stages of the disease since an impairment of olfactory identification is present at the clinical stage of AD. Our goal was therefore, (1) to evaluate the grey matter volume (GMV) of central olfactory processing regions in prodromal AD and (2) to assess its association with episodic memory. We included 34 cognitively normal healthy controls (HC), 92 individuals with subjective cognitive decline (SCD), and 40 with mild cognitive impairment (MCI). We performed regions of interest analysis (ROI) using two different approaches, allowing to extract GMV from (1) atlas-based anatomical ROIs and from (2) functional and non-functional subregions of these ROIs (olfactory ROIs and non-olfactory ROIs). Participants with MCI exhibited smaller olfactory ROIs GMV, including significant reductions in the piriform cortex, amygdala, entorhinal cortex, and left hippocampus compared to other groups (p ≤ 0.05, corrected). No significant effect was found regarding anatomical or non-olfactory ROIs GMV. The left hippocampus olfactory ROI GMV was correlated with episodic memory performance (p < 0.05 corrected). Limbic/medial-temporal olfactory processing areas are specifically atrophied at the MCI stage, and the degree of atrophy might predict cognitive decline in AD early stages.
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Affiliation(s)
- Benoît Jobin
- Department of Psychology, Université du Québec à Trois-Rivières, Qc, Canada; Research Centre of the Institut universitaire de Gériatrie de Montréal, Qc, Canada; Research Centre of the Hôpital du Sacré-Cœur de Montréal, Qc, Canada.
| | - Benjamin Boller
- Department of Psychology, Université du Québec à Trois-Rivières, Qc, Canada; Research Centre of the Institut universitaire de Gériatrie de Montréal, Qc, Canada
| | - Johannes Frasnelli
- Research Centre of the Hôpital du Sacré-Cœur de Montréal, Qc, Canada; Department of Anatomy, Université du Québec à Trois-Rivières, Qc, Canada
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4
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González LM, Bourissai A, Lessard-Beaudoin M, Lebel R, Tremblay L, Lepage M, Graham RK. Amelioration of Cognitive and Olfactory System Deficits in APOE4 Transgenic Mice with DHA Treatment. Mol Neurobiol 2023; 60:5624-5641. [PMID: 37329383 DOI: 10.1007/s12035-023-03401-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 05/24/2023] [Indexed: 06/19/2023]
Abstract
Olfactory dysfunction and atrophy of olfactory brain regions are observed early in mild cognitive impairment and Alzheimer disease. Despite substantial evidence showing neuroprotective effects in MCI/AD with treatment of docosahexaenoic acid (DHA), an omega-3 fatty acid, few studies have assessed DHA and its effects on the olfactory system deficits. We therefore performed structural (MRI), functional (olfactory behavior, novel object recognition), and molecular (markers of apoptosis and inflammation) assessments of APOE4 and wild-type mice ± DHA treatment at 3, 6, and 12 months of age. Our results demonstrate that APOE4 mice treated with the control diet show recognition memory deficits, abnormal olfactory habituation, and discrimination abilities and an increase in IBA-1 immunoreactivity in the olfactory bulb. These phenotypes were not present in APOE4 mice treated with a DHA diet. Alterations in some brain regions' weights and/or volumes were observed in the APOPE4 mice and may be due to caspase activation and/or neuroinflammatory events. These results suggest that the consumption of a diet rich in DHA may provide some benefit to E4 carriers but may not alleviate all symptoms.
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Affiliation(s)
- Laura Martínez González
- Research Centre on Aging CIUSSS de l'Estrie-CHUS, Sherbrooke, Quebec, Canada
- Department of Pharmacology and Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001 12e Avenue Nord, QC, J1H 5N4, Sherbrooke, Canada
| | - Adam Bourissai
- Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, Faculty of Medicine and Health Sciences, Sherbrooke, Quebec, J1H 5N4, Canada
| | - Mélissa Lessard-Beaudoin
- Research Centre on Aging CIUSSS de l'Estrie-CHUS, Sherbrooke, Quebec, Canada
- Department of Pharmacology and Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001 12e Avenue Nord, QC, J1H 5N4, Sherbrooke, Canada
| | - Réjean Lebel
- Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, Faculty of Medicine and Health Sciences, Sherbrooke, Quebec, J1H 5N4, Canada
| | - Luc Tremblay
- Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, Faculty of Medicine and Health Sciences, Sherbrooke, Quebec, J1H 5N4, Canada
| | - Martin Lepage
- Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, Faculty of Medicine and Health Sciences, Sherbrooke, Quebec, J1H 5N4, Canada
| | - Rona K Graham
- Research Centre on Aging CIUSSS de l'Estrie-CHUS, Sherbrooke, Quebec, Canada.
- Department of Pharmacology and Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001 12e Avenue Nord, QC, J1H 5N4, Sherbrooke, Canada.
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Brunert D, Quintela RM, Rothermel M. The anterior olfactory nucleus revisited - an emerging role for neuropathological conditions? Prog Neurobiol 2023:102486. [PMID: 37343762 DOI: 10.1016/j.pneurobio.2023.102486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 06/14/2023] [Accepted: 06/16/2023] [Indexed: 06/23/2023]
Abstract
Olfaction is an important sensory modality for many species and greatly influences animal and human behavior. Still, much about olfactory perception remains unknown. The anterior olfactory nucleus is one of the brain's central early olfactory processing areas. Located directly posterior to the olfactory bulb in the olfactory peduncle with extensive in- and output connections and unique cellular composition, it connects olfactory processing centers of the left and right hemispheres. Almost 20 years have passed since the last comprehensive review on the anterior olfactory nucleus has been published and significant advances regarding its anatomy, function, and pathophysiology have been made in the meantime. Here we briefly summarize previous knowledge on the anterior olfactory nucleus, give detailed insights into the progress that has been made in recent years, and map out its emerging importance in translational research of neurological diseases.
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Affiliation(s)
- Daniela Brunert
- Institute of Physiology, Medical Faculty, Otto-von-Guericke-University, 39120 Magdeburg, Germany
| | | | - Markus Rothermel
- Institute of Physiology, Medical Faculty, Otto-von-Guericke-University, 39120 Magdeburg, Germany.
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6
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Flores J, Fillion ML, LeBlanc AC. Caspase-1 inhibition improves cognition without significantly altering amyloid and inflammation in aged Alzheimer disease mice. Cell Death Dis 2022; 13:864. [PMID: 36220815 PMCID: PMC9553979 DOI: 10.1038/s41419-022-05290-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 09/21/2022] [Accepted: 09/22/2022] [Indexed: 11/07/2022]
Abstract
Human genetic and animal model studies indicate that brain microglial inflammation is a primary driver of cognitive impairment in Alzheimer Disease (AD). Inflammasome-activated Caspase-1 (Casp1) is associated with both AD microglial inflammation and neuronal degeneration. In mice, Casp1 genetic ablation or VX-765 small molecule inhibition of Casp1 given at onset of cognitive deficits strongly supports the association between microglial inflammation and cognitive impairment. Here, VX-765 significantly improved episodic and spatial memory impairment eight months after the onset of cognitive impairment in aged AD mice with significant amyloid beta peptide (Aβ) accumulation and microglial inflammation. Unexpectedly, while cognitive improvement was associated with dendritic spine density and hippocampal synaptophysin level recovery, VX-765 only slightly decreased Aβ deposition and did not alter biochemically-measured Aβ levels. Furthermore, increased hippocampal Iba1+-microglia, GFAP+-astrocytes, IL-1β, and TNF-α levels were unaltered by VX-765. These results support the hypothesis that neuronal degeneration, not Aβ or microglial inflammation, drives cognitive impairment in AD.
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Affiliation(s)
- Joseph Flores
- grid.414980.00000 0000 9401 2774Lady Davis Institute for Medical Research at Jewish General Hospital, Montréal, QC Canada
| | - Marie-Lyne Fillion
- grid.414980.00000 0000 9401 2774Lady Davis Institute for Medical Research at Jewish General Hospital, Montréal, QC Canada
| | - Andréa C. LeBlanc
- grid.414980.00000 0000 9401 2774Lady Davis Institute for Medical Research at Jewish General Hospital, Montréal, QC Canada ,grid.14709.3b0000 0004 1936 8649Department of Neurology and Neurosurgery, McGill University, Montréal, QC Canada
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7
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Boyarko B, Hook V. Human Tau Isoforms and Proteolysis for Production of Toxic Tau Fragments in Neurodegeneration. Front Neurosci 2021; 15:702788. [PMID: 34744602 PMCID: PMC8566764 DOI: 10.3389/fnins.2021.702788] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 09/09/2021] [Indexed: 01/27/2023] Open
Abstract
The human tau protein is implicated in a wide range of neurodegenerative “tauopathy” diseases, consisting of Alzheimer’s disease (AD) and frontotemporal lobar degeneration which includes progressive supranuclear palsy, corticobasal degeneration, Pick’s disease, and FTLD-tau (frontotemporal dementia with parkinsonism caused by MAPT mutations). Tau gene transcripts in the human brain undergo alternative splicing to yield 6 different tau protein isoforms that are expressed in different ratios in neurodegeneration which result in tau pathology of paired-helical filaments, neurofibrillary tangles, and tau fibrillar aggregates with detrimental microtubule destabilization. Protease-mediated tau truncation is an important post-translational modification (PTM) which drives neurodegeneration in a tau fragment-dependent manner. While numerous tau fragments have been identified, knowledge of the proteolytic steps that convert each parent tau isoform into specific truncated tau fragments has not yet been fully defined. An improved understanding of the relationships between tau isoforms and their proteolytic processing to generate neurotoxic tau fragments is important to the field. This review evaluates tau isoform expression patterns including PTMs and mutations that influence proteolysis of tau to generate toxic fragments that drive cognitive deficits in AD and other tauopathy models. This assessment identifies the gap in the field on understanding the details of proteolytic steps used to convert each tau isoform into fragments. Knowledge of the processing mechanisms of tau isoforms can lead to new protease targeted drug strategies to prevent the formation of toxic tau fragments in tauopathy neurodegenerative diseases.
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Affiliation(s)
- Ben Boyarko
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Vivian Hook
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States.,Department of Neurosciences and Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA, United States
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8
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Lessard-Beaudoin M, M Gonzalez L, AlOtaibi M, Chouinard-Watkins R, Plourde M, Calon F, Graham RK. Diet enriched in omega-3 fatty acids alleviates olfactory system deficits in APOE4 transgenic mice. Eur J Neurosci 2021; 54:7092-7108. [PMID: 34549475 DOI: 10.1111/ejn.15472] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 09/10/2021] [Accepted: 09/14/2021] [Indexed: 11/30/2022]
Abstract
Olfactory dysfunction is observed in several neurological disorders including Mild Cognitive Impairment (MCI) and Alzheimer disease (AD). These deficits occur early and correlate with global cognitive performance, depression and degeneration of olfactory regions in the brain. Despite extensive human studies, there has been little characterization of the olfactory system in models of AD. In order to determine if olfactory structural and/or molecular phenotypes are observed in a model expressing a genetic risk factor for AD, we assessed the olfactory bulb (OB) in APOE4 transgenic mice. A significant decrease in OB weight was observed at 12 months of age in APOE4 mice concurrent with inflammation and decreased NeuN expression. In order to determine if a diet rich in omega-3s may alleviate the olfactory system phenotypes observed, we assessed WT and APOE4 mice on a docosahexaenoic acid (DHA) diet. APOE4 mice on a DHA diet did not present with atrophy of the OB, and the alterations in NeuN and IBA-1 expression were alleviated. Furthermore, alterations in caspase mRNA and protein expression in the APOE4 OB were not observed with a DHA diet. Similar to the human AD condition, OB atrophy is an early phenotype in the APOE4 mice and concurrent with inflammation. These data support a link between the structural olfactory brain region atrophy and the olfactory dysfunction observed in AD and suggest that inflammation and cell death pathways may contribute to the olfactory deficits observed. Furthermore, the results suggest that diets enriched in DHA may provide benefit to APOE4 allele carriers.
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Affiliation(s)
- Melissa Lessard-Beaudoin
- Research Center on Aging, CIUSSS de L'Estrie - CHUS, Sherbrooke, Quebec, Canada.,Department of Pharmacology and Physiology, University of Sherbrooke, Sherbrooke, Quebec, Canada
| | - Laura M Gonzalez
- Research Center on Aging, CIUSSS de L'Estrie - CHUS, Sherbrooke, Quebec, Canada.,Department of Pharmacology and Physiology, University of Sherbrooke, Sherbrooke, Quebec, Canada
| | - Majed AlOtaibi
- Research Center on Aging, CIUSSS de L'Estrie - CHUS, Sherbrooke, Quebec, Canada.,Department of Pharmacology and Physiology, University of Sherbrooke, Sherbrooke, Quebec, Canada.,Department of Neuroscience, University of Sheffield, Sheffield, UK
| | - Raphaël Chouinard-Watkins
- Research Center on Aging, CIUSSS de L'Estrie - CHUS, Sherbrooke, Quebec, Canada.,Department of Medicine, University of Sherbrooke, Sherbrooke, Quebec, Canada
| | - Melanie Plourde
- Research Center on Aging, CIUSSS de L'Estrie - CHUS, Sherbrooke, Quebec, Canada.,Department of Medicine, University of Sherbrooke, Sherbrooke, Quebec, Canada
| | - Frederic Calon
- Faculty of Pharmacy, Centre de Recherche du CHU de Québec, Université Laval, Quebec City, Quebec, Canada
| | - Rona K Graham
- Research Center on Aging, CIUSSS de L'Estrie - CHUS, Sherbrooke, Quebec, Canada.,Department of Pharmacology and Physiology, University of Sherbrooke, Sherbrooke, Quebec, Canada
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9
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Rare CASP6N73T variant associated with hippocampal volume exhibits decreased proteolytic activity, synaptic transmission defect, and neurodegeneration. Sci Rep 2021; 11:12695. [PMID: 34135352 PMCID: PMC8209045 DOI: 10.1038/s41598-021-91367-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 05/25/2021] [Indexed: 01/22/2023] Open
Abstract
Caspase-6 (Casp6) is implicated in Alzheimer disease (AD) cognitive impairment and pathology. Hippocampal atrophy is associated with cognitive impairment in AD. Here, a rare functional exonic missense CASP6 single nucleotide polymorphism (SNP), causing the substitution of asparagine with threonine at amino acid 73 in Casp6 (Casp6N73T), was associated with hippocampal subfield CA1 volume preservation. Compared to wild type Casp6 (Casp6WT), recombinant Casp6N73T altered Casp6 proteolysis of natural substrates Lamin A/C and α-Tubulin, but did not alter cleavage of the Ac-VEID-AFC Casp6 peptide substrate. Casp6N73T-transfected HEK293T cells showed elevated Casp6 mRNA levels similar to Casp6WT-transfected cells, but, in contrast to Casp6WT, did not accumulate active Casp6 subunits nor show increased Casp6 enzymatic activity. Electrophysiological and morphological assessments showed that Casp6N73T recombinant protein caused less neurofunctional damage and neurodegeneration in hippocampal CA1 pyramidal neurons than Casp6WT. Lastly, CASP6 mRNA levels were increased in several AD brain regions confirming the implication of Casp6 in AD. These studies suggest that the rare Casp6N73T variant may protect against hippocampal atrophy due to its altered catalysis of natural protein substrates and intracellular instability thus leading to less Casp6-mediated damage to neuronal structure and function.
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10
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Al-Otaibi M, Lessard-Beaudoin M, Castellano CA, Gris D, Cunnane SC, Graham RK. Volumetric MRI demonstrates atrophy of the olfactory cortex in AD. Curr Alzheimer Res 2020; 17:904-915. [PMID: 33327913 DOI: 10.2174/1567205017666201215120909] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 10/02/2020] [Accepted: 11/05/2020] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Alzheimer disease (AD) is a chronic neurodegenerative disorder that affects millions of individuals worldwide. Symptoms include memory dysfunction and deficits in attention, planning, language, and overall cognitive function. Olfactory dysfunction is a common symptom of AD and evidence supports that it is an early marker. Furthermore, olfactory bulb and entorhinal cortex atrophy are well described in AD. However, in AD, no studies have assessed the olfactory cortex as a whole and if sex effects are observed. METHODS Magnetic Resonance Imaging was used to scan 39 participants with an average age of 72 years and included men and women. AAL Single-Subject Atlas (implemented in PNEURO tool - PMOD 3.8) was used to determine the volume of the olfactory cortex and the hippocampus. Olfactory cortex volume was lower in both men and women AD cases compared with controls. This decrease was more apparent in the left olfactory cortex and was influenced by age. As expected, hippocampal volume was also significantly reduced in AD. However, this was only observed in the male cohort. A significant correlation was observed between levels of education and hippocampal volume in controls that were not detected in the AD participants. Asymmetry was observed in the olfactory cortex volume when comparing left and right volumes in both the control and AD participants, which was not observed in the hippocampus. RESULTS These data highlight the importance of the role of olfactory cortical atrophy in the pathogenesis of AD and the interplay between the olfactory deficits and degeneration of olfactory regions in the brain.
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Affiliation(s)
| | | | | | - Denis Gris
- Department of Pediatrics, University of Sherbrooke, Sherbrooke, QC, Canada
| | - Stephen C Cunnane
- Research Center on Aging, CIUSSS-IUGS de l'Estrie-CHUS, Sherbrooke, QC, Canada
| | - Rona K Graham
- Research Center on Aging, CIUSSS-IUGS de l'Estrie-CHUS, Sherbrooke, QC, Canada
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11
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Velagapudi R, Kosoko AM, Olajide OA. Induction of Neuroinflammation and Neurotoxicity by Synthetic Hemozoin. Cell Mol Neurobiol 2019; 39:1187-1200. [PMID: 31332667 PMCID: PMC6764936 DOI: 10.1007/s10571-019-00713-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 07/13/2019] [Indexed: 12/22/2022]
Abstract
Hemozoin produced by Plasmodium falciparum during malaria infection has been linked to the neurological dysfunction in cerebral malaria. In this study, we determined whether a synthetic form of hemozoin (sHZ) produces neuroinflammation and neurotoxicity in cellular models. Incubation of BV-2 microglia with sHZ (200 and 400 µg/ml) induced significant elevation in the levels of TNFα, IL-6, IL-1β, NO/iNOS, phospho-p65, accompanied by an increase in DNA binding of NF-κB. Treatment of BV-2 microglia with sHZ increased protein levels of NLRP3 with accompanying increase in caspase-1 activity. In the presence of NF-κB inhibitor BAY11-7082 (10 µM), there was attenuation of sHZ-induced release of pro-inflammatory cytokines, NO/iNOS. In addition, increase in caspase-1/NLRP3 inflammasome activation was blocked by BAY11-7082. Pre-treatment with BAY11-7082 also reduced both phosphorylation and DNA binding of the p65 sub-unit. The NLRP3 inhibitor CRID3 (100 µM) did not prevent sHZ-induced release of TNFα and IL-6. However, production of IL-1β, NO/iNOS as well as caspase-1/NLRP3 activity was significantly reduced in the presence of CRID3. Incubation of differentiated neural progenitor (ReNcell VM) cells with sHZ resulted in a reduction in cell viability, accompanied by significant generation of cellular ROS and increased activity of caspase-6, while sHZ-induced neurotoxicity was prevented by N-acetylcysteine and Z-VEID-FMK. Taken together, this study shows that the synthetic form of hemozoin induces neuroinflammation through the activation of NF-κB and NLRP3 inflammasome. It is also proposed that sHZ induces ROS- and caspase-6-mediated neurotoxicity. These results have thrown more light on the actions of malarial hemozoin in the neurobiology of cerebral malaria.
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Affiliation(s)
- Ravikanth Velagapudi
- Department of Pharmacy, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK.,Department of Anesthesiology, Center for Translational Pain Medicine, Duke University Medical Center, Durham, NC, 27710, USA
| | - Ayokulehin M Kosoko
- Department of Pharmacy, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK
| | - Olumayokun A Olajide
- Department of Pharmacy, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK.
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Rösler TW, Tayaranian Marvian A, Brendel M, Nykänen NP, Höllerhage M, Schwarz SC, Hopfner F, Koeglsperger T, Respondek G, Schweyer K, Levin J, Villemagne VL, Barthel H, Sabri O, Müller U, Meissner WG, Kovacs GG, Höglinger GU. Four-repeat tauopathies. Prog Neurobiol 2019; 180:101644. [PMID: 31238088 DOI: 10.1016/j.pneurobio.2019.101644] [Citation(s) in RCA: 126] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 05/21/2019] [Accepted: 06/12/2019] [Indexed: 02/08/2023]
Abstract
Tau is a microtubule-associated protein with versatile functions in the dynamic assembly of the neuronal cytoskeleton. Four-repeat (4R-) tauopathies are a group of neurodegenerative diseases defined by cytoplasmic inclusions predominantly composed of tau protein isoforms with four microtubule-binding domains. Progressive supranuclear palsy, corticobasal degeneration, argyrophilic grain disease or glial globular tauopathy belong to the group of 4R-tauopathies. The present review provides an introduction in the current concept of 4R-tauopathies, including an overview of the neuropathological and clinical spectrum of these diseases. It describes the genetic and environmental etiological factors, as well as the contemporary knowledge about the pathophysiological mechanisms, including post-translational modifications, aggregation and fragmentation of tau, as well as the role of protein degradation mechanisms. Furthermore, current theories about disease propagation are discussed, involving different extracellular tau species and their cellular release and uptake mechanisms. Finally, molecular diagnostic tools for 4R-tauopathies, including tau-PET and fluid biomarkers, and investigational therapeutic strategies are presented. In summary, we report on 4R-tauopathies as overarching disease concept based on a shared pathophysiological concept, and highlight the challenges and opportunities on the way towards a causal therapy.
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Affiliation(s)
- Thomas W Rösler
- Dept. of Translational Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany; Dept. of Neurology, Technical University of Munich, School of Medicine, 81675 Munich, Germany
| | - Amir Tayaranian Marvian
- Dept. of Translational Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany; Dept. of Neurology, Technical University of Munich, School of Medicine, 81675 Munich, Germany
| | - Matthias Brendel
- Dept. of Nuclear Medicine, University of Munich, 81377 Munich, Germany
| | - Niko-Petteri Nykänen
- Dept. of Translational Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany
| | - Matthias Höllerhage
- Dept. of Translational Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany; Dept. of Neurology, Technical University of Munich, School of Medicine, 81675 Munich, Germany
| | - Sigrid C Schwarz
- Dept. of Translational Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany
| | | | - Thomas Koeglsperger
- Dept. of Neurology, University of Munich, 81377 Munich, Germany; German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany
| | - Gesine Respondek
- Dept. of Translational Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany; Dept. of Neurology, Technical University of Munich, School of Medicine, 81675 Munich, Germany
| | - Kerstin Schweyer
- Dept. of Translational Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany; Dept. of Neurology, Technical University of Munich, School of Medicine, 81675 Munich, Germany
| | - Johannes Levin
- Dept. of Neurology, University of Munich, 81377 Munich, Germany; German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany
| | - Victor L Villemagne
- Dept. of Molecular Imaging and Therapy, Austin Health, Heidelberg, VIC, 3084, Australia; The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia; Dept. of Medicine, Austin Health, University of Melbourne, Melbourne, VIC, Australia
| | - Henryk Barthel
- Dept. of Nuclear Medicine, University of Leipzig, 04103 Leipzig, Germany
| | - Osama Sabri
- Dept. of Nuclear Medicine, University of Leipzig, 04103 Leipzig, Germany
| | - Ulrich Müller
- Institute for Human Genetics, University of Giessen, 35392 Giessen, Germany
| | - Wassilios G Meissner
- Service de Neurologie, CHU Bordeaux, 33000 Bordeaux, France; Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France; Dept. of Medicine, University of Otago, Christchurch, New Zealand; New Zealand Brain Research Institute, Christchurch, New Zealand
| | - Gabor G Kovacs
- Institute of Neurology, Medical University of Vienna, 1090 Vienna, Austria; Dept. of Laboratory Medicine and Pathobiology, University of Toronto, Laboratory Medicine Program, University Health Network, Toronto, Canada; Tanz Centre for Research in Neurodegenerative Disease, Krembil Brain Institute, Toronto, Canada
| | - Günter U Höglinger
- Dept. of Translational Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany; Dept. of Neurology, Technical University of Munich, School of Medicine, 81675 Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany; Dept. of Neurology, Hannover Medical School, 30625 Hannover, Germany.
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Islam MI, Nagakannan P, Ogungbola O, Djordjevic J, Albensi BC, Eftekharpour E. Thioredoxin system as a gatekeeper in caspase-6 activation and nuclear lamina integrity: Implications for Alzheimer's disease. Free Radic Biol Med 2019; 134:567-580. [PMID: 30769159 DOI: 10.1016/j.freeradbiomed.2019.02.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 01/28/2019] [Accepted: 02/10/2019] [Indexed: 02/01/2023]
Abstract
Recent reports in pathophysiology of neurodegenerative diseases (ND) have linked nuclear lamina degradation/deficits to neuronal cell death. Lamin-B1 damage is specifically involved in this process leading to nuclear envelope invagination and heterochromatin rearrangement. The underlying mechanisms involved in these events are not yet defined. In this study, while examining the effect of Thioredoxin-1(Trx1) inhibition on cell death in a model of oxidative stress, we noted robust nuclear invagination in SH-SY5Y cells. Evaluation of nuclear lamina proteins revealed lamin-B1 cleavage that was prevented by caspase-6 (CASP6) inhibitor and exacerbated after pharmacologic/genetic inhibition of Trx1 system, but not after glutathione depletion. Activation of CASP6 was upstream of CASP3/7 activation and its inhibition was sufficient to prevent cell death in our system. The effect of Trx1 redox status on CASP6 activation was assessed by administration of reduced/oxidized forms in cell-free nuclei preparation and purified enzymatic assays. Although reduced Trx1 decreased CASP6 enzymatic activity and lamin-B1 cleavage, the fully oxidized Trx1 showed opposite effects. The enhanced CASP6 activation was also associated with lower levels of DJ-1, a neuroprotective and master regulator of cellular antioxidants. The implication of our findings in ND pathophysiology was strengthened with detection of lower Trx1 levels in the hippocampi tissue of a mouse model of Alzheimer's disease. This coincided with higher CASP6 activation resulting in increased lamin-B1 and DJ-1 depletion. This study provides a first mechanistic explanation for the key regulatory role of Trx1 as a gatekeeper in activation of CASP6 and induction of nuclear invagination, an important player in ND pathophysiology.
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Affiliation(s)
- Md Imamul Islam
- Regenerative Medicine Program and Spinal Cord Research Centre, Canada; Dept. Physiology and Pathophysiology, University of Manitoba, Winnipeg, Canada
| | - Pandian Nagakannan
- Regenerative Medicine Program and Spinal Cord Research Centre, Canada; Dept. Physiology and Pathophysiology, University of Manitoba, Winnipeg, Canada
| | - Olamide Ogungbola
- Regenerative Medicine Program and Spinal Cord Research Centre, Canada; Dept. Physiology and Pathophysiology, University of Manitoba, Winnipeg, Canada
| | - Jelena Djordjevic
- Division of Neurodegenerative Disorders, St. Boniface Hospital Research, Winnipeg, Manitoba, Canada; Department of Pharmacology and Therapeutics, Faculty of Health Sciences, College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Benedict C Albensi
- Division of Neurodegenerative Disorders, St. Boniface Hospital Research, Winnipeg, Manitoba, Canada; Department of Pharmacology and Therapeutics, Faculty of Health Sciences, College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Eftekhar Eftekharpour
- Regenerative Medicine Program and Spinal Cord Research Centre, Canada; Dept. Physiology and Pathophysiology, University of Manitoba, Winnipeg, Canada.
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Olfactory Disorder Pattern in Patients With Neurological Diseases Excluding Psychiatric and Traumatic Aetiologies. ACTA OTORRINOLARINGOLOGICA ESPANOLA 2018. [DOI: 10.1016/j.otoeng.2017.10.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Aqrabawi AJ, Kim JC. Hippocampal projections to the anterior olfactory nucleus differentially convey spatiotemporal information during episodic odour memory. Nat Commun 2018; 9:2735. [PMID: 30013078 PMCID: PMC6048034 DOI: 10.1038/s41467-018-05131-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Accepted: 06/11/2018] [Indexed: 01/13/2023] Open
Abstract
The hippocampus is essential for representing spatiotemporal context and establishing its association with the sensory details of daily life to form episodic memories. The olfactory cortex in particular shares exclusive anatomical connections with the hippocampus as a result of their common evolutionary history. Here we selectively inhibit hippocampal projections to the anterior olfactory nucleus (AON) during behavioural tests of contextually cued odour recall. We find that spatial odour memory and temporal odour memory are independently impaired following inhibition of distinct, topographically organized hippocampal-AON pathways. Our results not only reveal a longstanding unknown function for the AON but offer new mechanistic insights regarding the representation of odours in episodic memory.
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Affiliation(s)
- Afif J Aqrabawi
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada, M5S 3G5
| | - Jun Chul Kim
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada, M5S 3G5.
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada, M5S 3G3.
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Parallel odor processing by mitral and middle tufted cells in the olfactory bulb. Sci Rep 2018; 8:7625. [PMID: 29769664 PMCID: PMC5955882 DOI: 10.1038/s41598-018-25740-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 04/24/2018] [Indexed: 12/27/2022] Open
Abstract
The olfactory bulb (OB) transforms sensory input into spatially and temporally organized patterns of activity in principal mitral (MC) and middle tufted (mTC) cells. Thus far, the mechanisms underlying odor representations in the OB have been mainly investigated in MCs. However, experimental findings suggest that MC and mTC may encode parallel and complementary odor representations. We have analyzed the functional roles of these pathways by using a morphologically and physiologically realistic three-dimensional model to explore the MC and mTC microcircuits in the glomerular layer and deeper plexiform layer. The model makes several predictions. MCs and mTCs are controlled by similar computations in the glomerular layer but are differentially modulated in deeper layers. The intrinsic properties of mTCs promote their synchronization through a common granule cell input. Finally, the MC and mTC pathways can be coordinated through the deep short-axon cells in providing input to the olfactory cortex. The results suggest how these mechanisms can dynamically select the functional network connectivity to create the overall output of the OB and promote the dynamic synchronization of glomerular units for any given odor stimulus.
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de Haro-Licer J, González-Fernández A, Planas-Comes A, González-Ares JA. Olfactory Disorder Pattern In Patients With Neurological Diseases Excluding Psychiatric And Traumatic Aetiologies. ACTA OTORRINOLARINGOLOGICA ESPANOLA 2018; 69:318-324. [PMID: 29580587 DOI: 10.1016/j.otorri.2017.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 10/16/2017] [Accepted: 10/18/2017] [Indexed: 10/17/2022]
Abstract
INTRODUCTION The most common cause of olfactory ENT disorders are colds and flu, chronic sinusitis, allergies and traumatic brain injury. Rarer aetiologies include certain neurological, psychiatric and metabolic injuries. TARGET The aim of this paper was to check the sort of olfactory disorders found in people who have suffered a brain injury, excluding: cranial traumas, psychiatric diseases, epilepsy, Parkinson's and Alzheimer's disease, and synaesthesia. MATERIAL AND METHODS A descriptive study based on 61 patients with diagnoses of various neurological injuries, which were tested by BAST-24 olfactometer. The results were compared with those of a control group (n= 120). RESULTS The results show major impairment in these patients' olfactory sense. The neurological injury patients were able to detect from 60-77% of the odours, while the control group were able to detect between 98-100%. The neurological patients were able, at best, to identify, 11-32% of the odours correctly, while the control group were able to correctly detect between 59 -75%. The differences between odour detection and correct identification were statistically significant (p<.05). CONCLUSIONS We concluded: a) Neurological injury, not caused by traumatic brain injury, psychiatric disorders or ENT diseases, ranged from 68-89% of the olfactory failures. b) We must bear in mind that these sorts of injuries can cause olfactory disorders. c) ENT and Neurologists should collaborate in the treatment of these disorders.
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Affiliation(s)
- Josep de Haro-Licer
- Servicio de Otorrinolaringología, Hospital Municipal de Badalona-BSA, Barcelona, España. 15583jhl.@comb.cat
| | | | - Albert Planas-Comes
- Servicio de Neurología-Medicina Interna, Hospital Municipal de Badalona-BSA, Barcelona, España
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Bennett DA, Buchman AS, Boyle PA, Barnes LL, Wilson RS, Schneider JA. Religious Orders Study and Rush Memory and Aging Project. J Alzheimers Dis 2018; 64:S161-S189. [PMID: 29865057 PMCID: PMC6380522 DOI: 10.3233/jad-179939] [Citation(s) in RCA: 650] [Impact Index Per Article: 108.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND The Religious Orders Study and Rush Memory and Aging Project are both ongoing longitudinal clinical-pathologic cohort studies of aging and Alzheimer's disease (AD). OBJECTIVES To summarize progress over the past five years and its implications for understanding neurodegenerative diseases. METHODS Participants in both studies are older adults who enroll without dementia and agree to detailed longitudinal clinical evaluations and organ donation. The last review summarized findings through the end of 2011. Here we summarize progress and study findings over the past five years and discuss new directions for how these studies can inform on aging and AD in the future. RESULTS We summarize 1) findings on the relation of neurobiology to clinical AD; 2) neurobiologic pathways linking risk factors to clinical AD; 3) non-cognitive AD phenotypes including motor function and decision making; 4) the development of a novel drug discovery platform. CONCLUSION Complexity at multiple levels needs to be understood and overcome to develop effective treatments and preventions for cognitive decline and AD dementia.
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Affiliation(s)
- David A. Bennett
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL., USA
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL., USA
| | - Aron S. Buchman
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL., USA
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL., USA
| | - Patricia A. Boyle
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL., USA
- Department of Behavioral Sciences, Rush University Medical Center, Chicago, IL., USA
| | - Lisa L. Barnes
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL., USA
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL., USA
- Department of Behavioral Sciences, Rush University Medical Center, Chicago, IL., USA
| | - Robert S. Wilson
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL., USA
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL., USA
- Department of Behavioral Sciences, Rush University Medical Center, Chicago, IL., USA
| | - Julie A Schneider
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL., USA
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL., USA
- Department of Pathology (Neuropathology), Rush University Medical Center, Chicago, IL., USA
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Quinn JP, Corbett NJ, Kellett KAB, Hooper NM. Tau Proteolysis in the Pathogenesis of Tauopathies: Neurotoxic Fragments and Novel Biomarkers. J Alzheimers Dis 2018; 63:13-33. [PMID: 29630551 PMCID: PMC5900574 DOI: 10.3233/jad-170959] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/31/2018] [Indexed: 12/11/2022]
Abstract
With predictions showing that 131.5 million people worldwide will be living with dementia by 2050, an understanding of the molecular mechanisms underpinning disease is crucial in the hunt for novel therapeutics and for biomarkers to detect disease early and/or monitor disease progression. The metabolism of the microtubule-associated protein tau is altered in different dementias, the so-called tauopathies. Tau detaches from microtubules, aggregates into oligomers and neurofibrillary tangles, which can be secreted from neurons, and spreads through the brain during disease progression. Post-translational modifications exacerbate the production of both oligomeric and soluble forms of tau, with proteolysis by a range of different proteases being a crucial driver. However, the impact of tau proteolysis on disease progression has been overlooked until recently. Studies have highlighted that proteolytic fragments of tau can drive neurodegeneration in a fragment-dependent manner as a result of aggregation and/or transcellular propagation. Proteolytic fragments of tau have been found in the cerebrospinal fluid and plasma of patients with different tauopathies, providing an opportunity to develop these fragments as novel disease progression biomarkers. A range of therapeutic strategies have been proposed to halt the toxicity associated with proteolysis, including reducing protease expression and/or activity, selectively inhibiting protease-substrate interactions, and blocking the action of the resulting fragments. This review highlights the importance of tau proteolysis in the pathogenesis of tauopathies, identifies putative sites during tau fragment-mediated neurodegeneration that could be targeted therapeutically, and discusses the potential use of proteolytic fragments of tau as biomarkers for different tauopathies.
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Affiliation(s)
- James P. Quinn
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Nicola J. Corbett
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Katherine A. B. Kellett
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Nigel M. Hooper
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
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