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German‐Castelan L, Shanks HRC, Gros R, Saito T, Saido TC, Saksida LM, Bussey TJ, Prado MAM, Schmitz TW, Prado VF. Sex-dependent cholinergic effects on amyloid pathology: A translational study. Alzheimers Dement 2024; 20:995-1012. [PMID: 37846816 PMCID: PMC10916951 DOI: 10.1002/alz.13481] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 08/05/2023] [Accepted: 08/17/2023] [Indexed: 10/18/2023]
Abstract
INTRODUCTION About two-thirds of Alzheimer's Disease (AD) patients are women, who exhibit more severe pathology and cognitive decline than men. Whether biological sex causally modulates the relationship between cholinergic signaling and amyloid pathology remains unknown. METHODS We quantified amyloid beta (Aβ) in male and female App-mutant mice with either decreased or increased cholinergic tone and examined the impact of ovariectomy and estradiol replacement in this relationship. We also investigated longitudinal changes in basal forebrain (cholinergic function) and Aβ in elderly individuals. RESULTS We show a causal relationship between cholinergic tone and amyloid pathology in males and ovariectomized female mice, which is decoupled in ovary-intact and ovariectomized females receiving estradiol. In elderly humans, cholinergic loss exacerbates Aβ. DISCUSSION Our findings emphasize the importance of reflecting human menopause in mouse models. They also support a role for therapies targeting estradiol and cholinergic signaling to reduce Aβ. HIGHLIGHTS Cholinergic tone regulates amyloid beta (Aβ) pathology in males and ovariectomized female mice. Estradiol uncouples the relationship between cholinergic tone and Aβ. In elderly humans, cholinergic loss correlates with increased Aβ in both sexes.
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Affiliation(s)
- Liliana German‐Castelan
- Robarts Research InstituteSchulich School of Medicine and DentistryUniversity of Western OntarioLondonOntarioCanada
- Neuroscience programSchulich School of Medicine and DentistryUniversity of Western OntarioLondonOntarioCanada
| | - Hayley R. C. Shanks
- Neuroscience programSchulich School of Medicine and DentistryUniversity of Western OntarioLondonOntarioCanada
| | - Robert Gros
- Robarts Research InstituteSchulich School of Medicine and DentistryUniversity of Western OntarioLondonOntarioCanada
- Department of MedicineSchulich School of Medicine & DentistryUniversity of Western OntarioLondonOntarioCanada
- Department of Physiology and PharmacologySchulich School of Medicine & DentistryUniversity of Western OntarioLondonOntarioCanada
| | - Takashi Saito
- Department of Neurocognitive ScienceInstitute of Brain ScienceNagoya City University Graduate School of Medical SciencesNagoyaJapan
- Laboratory for Proteolytic NeuroscienceRIKEN Center for Brain ScienceWako, SaitamaJapan
| | - Takaomi C. Saido
- Laboratory for Proteolytic NeuroscienceRIKEN Center for Brain ScienceWako, SaitamaJapan
| | - Lisa M. Saksida
- Robarts Research InstituteSchulich School of Medicine and DentistryUniversity of Western OntarioLondonOntarioCanada
- Neuroscience programSchulich School of Medicine and DentistryUniversity of Western OntarioLondonOntarioCanada
- Department of Physiology and PharmacologySchulich School of Medicine & DentistryUniversity of Western OntarioLondonOntarioCanada
- Western Institute for NeuroscienceUniversity of Western OntarioLondonOntarioCanada
| | - Timothy J. Bussey
- Robarts Research InstituteSchulich School of Medicine and DentistryUniversity of Western OntarioLondonOntarioCanada
- Neuroscience programSchulich School of Medicine and DentistryUniversity of Western OntarioLondonOntarioCanada
- Department of Physiology and PharmacologySchulich School of Medicine & DentistryUniversity of Western OntarioLondonOntarioCanada
- Western Institute for NeuroscienceUniversity of Western OntarioLondonOntarioCanada
| | - Marco A. M. Prado
- Robarts Research InstituteSchulich School of Medicine and DentistryUniversity of Western OntarioLondonOntarioCanada
- Neuroscience programSchulich School of Medicine and DentistryUniversity of Western OntarioLondonOntarioCanada
- Department of Physiology and PharmacologySchulich School of Medicine & DentistryUniversity of Western OntarioLondonOntarioCanada
- Western Institute for NeuroscienceUniversity of Western OntarioLondonOntarioCanada
- Department of Anatomy and Cell BiologySchulich School of Medicine & DentistryUniversity of Western OntarioLondonOntarioCanada
| | - Taylor W. Schmitz
- Robarts Research InstituteSchulich School of Medicine and DentistryUniversity of Western OntarioLondonOntarioCanada
- Neuroscience programSchulich School of Medicine and DentistryUniversity of Western OntarioLondonOntarioCanada
- Western Institute for NeuroscienceUniversity of Western OntarioLondonOntarioCanada
- Lawson Health Research InstituteSt. Joseph's HospitalLondonOntarioCanada
| | - Vania F. Prado
- Robarts Research InstituteSchulich School of Medicine and DentistryUniversity of Western OntarioLondonOntarioCanada
- Neuroscience programSchulich School of Medicine and DentistryUniversity of Western OntarioLondonOntarioCanada
- Department of Physiology and PharmacologySchulich School of Medicine & DentistryUniversity of Western OntarioLondonOntarioCanada
- Western Institute for NeuroscienceUniversity of Western OntarioLondonOntarioCanada
- Department of Anatomy and Cell BiologySchulich School of Medicine & DentistryUniversity of Western OntarioLondonOntarioCanada
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Intrahippocampal Inoculation of Aβ 1-42 Peptide in Rat as a Model of Alzheimer's Disease Identified MicroRNA-146a-5p as Blood Marker with Anti-Inflammatory Function in Astrocyte Cells. Cells 2023; 12:cells12050694. [PMID: 36899831 PMCID: PMC10000752 DOI: 10.3390/cells12050694] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/09/2023] [Accepted: 02/13/2023] [Indexed: 02/25/2023] Open
Abstract
Circulating microRNAs (miRNAs) have aroused a lot of interest as reliable blood diagnostic biomarkers of Alzheimer's disease (AD). Here, we investigated the panel of expressed blood miRNAs in response to aggregated Aβ1-42 peptides infused in the hippocampus of adult rats to mimic events of the early onset of non-familial AD disorder. Aβ1-42 peptides in the hippocampus led to cognitive impairments associated with an astrogliosis and downregulation of circulating miRNA-146a-5p, -29a-3p, -29c-3p, -125b-5p, and-191-5p. We established the kinetics of expression of selected miRNAs and found differences with those detected in the APPswe/PS1dE9 transgenic mouse model. Of note, miRNA-146a-5p was exclusively dysregulated in the Aβ-induced AD model. The treatment of primary astrocytes with Aβ1-42 peptides led to miRNA-146a-5p upregulation though the activation of the NF-κB signaling pathway, which in turn downregulated IRAK-1 but not TRAF-6 expression. As a consequence, no induction of IL-1β, IL-6, or TNF-α was detected. Astrocytes treated with a miRNA-146-5p inhibitor rescued IRAK-1 and changed TRAF-6 steady-state levels that correlated with the induction of IL-6, IL-1β, and CXCL1 production, indicating that miRNA-146a-5p operates anti-inflammatory functions through a NF-κB pathway negative feedback loop. Overall, we report a panel of circulating miRNAs that correlated with Aβ1-42 peptides' presence in the hippocampus and provide mechanistic insights into miRNA-146a-5p biological function in the development of the early stage of sporadic AD.
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Wu Y, Zhang T, Li X, Wei Y, Li X, Wang S, Liu J, Li D, Wang S, Ye T. Borneol-driven meningeal lymphatic drainage clears amyloid-β peptide to attenuate Alzheimer-like phenotype in mice. Theranostics 2023; 13:106-124. [PMID: 36593948 PMCID: PMC9800736 DOI: 10.7150/thno.76133] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 10/03/2022] [Indexed: 12/03/2022] Open
Abstract
Rationale: The accumulation and clearance of amyloid-β (Aβ) peptides play a crucial role in the pathogenesis of Alzheimer's disease (AD). The (re)discovery of meningeal lymphatic vessels in recent years has focused attention on the lymphatic clearance of Aβ and has become a promising therapeutic target for such diseases. However, there is a lack of small molecular compounds that could clearly regulate meningeal lymphatic drainage to remove Aβ from the brain. Methods: We investigated the effect of borneol on meningeal lymphatic clearance of macromolecules with different molecular weights (including Aβ) in the brain. To further investigate the mechanism of borneol regulating meningeal lymphatic drainage, immunofluorescence staining, western blotting, ELISA, RT-qPCR, and Nitric Oxide assay kits were used. The cognitive function of AD mice after borneol treatment was evaluated using two behavioral tests: open field (OF) and Morris water maze (MWM). Results: This study discovered that borneol could accelerate the lymphatic clearance of Aβ from the brain by enhancing meningeal lymphatic drainage. Preliminary mechanism analysis revealed that borneol could improve the permeability and inner diameter of lymphatic vessels, allowing macromolecules to drain into the cervical lymph nodes (CLNS) and then be transported to the lymphatic circulation. To speed up the clearance of macromolecules, borneol also stimulated lymphatic constriction by lowering the level of nitric oxide in the meninges. In addition, borneol stimulated lymphangiogenesis by increasing the levels of FOXC2, VEGFC, and LYVE-1 in the meninges, which promoted the clearance rates of macromolecules. Borneol improved meningeal lymphatic clearance not only for Aβ but also for other macromolecular polymers (molecular weight in the range of 2 KD - 45 KD. Borneol ameliorated cognitive deficits and alleviated brain Aβ burden in Aβ-injected mice. Conclusions: Our findings not only provide a strategy to regulate lymphatic clearance pathways of macromolecules in the brain, but also new targets and ideas for treating neurodegenerative diseases like AD. Furthermore, our findings indicate that borneol is a promising therapeutic drug for AD.
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Affiliation(s)
- Yue Wu
- Department of Pharmaceutics, College of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Tingting Zhang
- Department of Pharmaceutics, College of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Xianqiang Li
- Department of Pharmaceutics, College of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Yimei Wei
- Department of Pharmaceutics, College of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Xinyu Li
- Department of Pharmaceutics, College of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Sixue Wang
- Department of Pharmaceutics, College of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Jun Liu
- Department of Pharmaceutics, Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang Junhong Pharmaceutical Technology Co., Ltd. Shenyang, 110016, China.,Research and development center, Jiangsu Aidi Nano Biomedical Co., Ltd., Nantong, 226000, China
| | - Dan Li
- Department of Pharmaceutics, College of Chinese Pharmacy, Shenyang Pharmaceutical University, Shenyang, 110016, China.,Research and development center, Shenyang Junhong Pharmaceutical Technology Co., Ltd. Shenyang, 110031, China
| | - Shujun Wang
- Department of Pharmaceutics, College of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 110016, China.,✉ Corresponding authors: Tiantian Ye, E-mail: ; Shujun Wang, E-mail:
| | - Tiantian Ye
- Department of Pharmaceutics, College of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 110016, China.,✉ Corresponding authors: Tiantian Ye, E-mail: ; Shujun Wang, E-mail:
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MacKenzie JL, Ivanova N, Nell HJ, Giordano CR, Terlecky SR, Agca C, Agca Y, Walton PA, Whitehead SN, Cechetto DF. Microglial inflammation and cognitive dysfunction in comorbid rat models of striatal ischemic stroke and alzheimer’s disease: effects of antioxidant catalase-SKL on behavioral and cellular pathology. Neuroscience 2022; 487:47-65. [DOI: 10.1016/j.neuroscience.2022.01.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 01/26/2022] [Accepted: 01/28/2022] [Indexed: 12/25/2022]
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Paulo SL, Ribeiro-Rodrigues L, Rodrigues RS, Mateus JM, Fonseca-Gomes J, Soares R, Diógenes MJ, Solá S, Sebastião AM, Ribeiro FF, Xapelli S. Sustained Hippocampal Neural Plasticity Questions the Reproducibility of an Amyloid-β-Induced Alzheimer's Disease Model. J Alzheimers Dis 2021; 82:1183-1202. [PMID: 34151790 DOI: 10.3233/jad-201567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND The use of Alzheimer's disease (AD) models obtained by intracerebral infusion of amyloid-β (Aβ) has been increasingly reported in recent years. Nonetheless, these models may present important challenges. OBJECTIVE We have focused on canonical mechanisms of hippocampal-related neural plasticity to characterize a rat model obtained by an intracerebroventricular (icv) injection of soluble amyloid-β42 (Aβ42). METHODS Animal behavior was evaluated in the elevated plus maze, Y-Maze spontaneous or forced alternation, Morris water maze, and open field, starting 2 weeks post-Aβ42 infusion. Hippocampal neurogenesis was assessed 3 weeks after Aβ42 injection. Aβ deposition, tropomyosin receptor kinase B levels, and neuroinflammation were appraised at 3 and 14 days post-Aβ42 administration. RESULTS We found that immature neuronal dendritic morphology was abnormally enhanced, but proliferation and neuronal differentiation in the dentate gyrus was conserved one month after Aβ42 injection. Surprisingly, animal behavior did not reveal changes in cognitive performance nor in locomotor and anxious-related activity. Brain-derived neurotrophic factor related-signaling was also unchanged at 3 and 14 days post-Aβ icv injection. Likewise, astrocytic and microglial markers of neuroinflammation in the hippocampus were unaltered in these time points. CONCLUSION Taken together, our data emphasize a high variability and lack of behavioral reproducibility associated with these Aβ injection-based models, as well as the need for its further optimization, aiming at addressing the gap between preclinical AD models and the human disorder.
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Affiliation(s)
- Sara L Paulo
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Leonor Ribeiro-Rodrigues
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Rui S Rodrigues
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Joana M Mateus
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - João Fonseca-Gomes
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Rita Soares
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Biologia Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Maria J Diógenes
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Susana Solá
- Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Lisboa, Portugal
| | - Ana M Sebastião
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Filipa F Ribeiro
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Sara Xapelli
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
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Zhao LX, Chen MW, Qian Y, Yang QH, Ge YH, Chen HZ, Qiu Y. M1 Muscarinic Receptor Activation Rescues β-Amyloid-Induced Cognitive Impairment through AMPA Receptor GluA1 Subunit. Neuroscience 2019; 408:239-247. [PMID: 30981860 DOI: 10.1016/j.neuroscience.2019.04.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 03/15/2019] [Accepted: 04/02/2019] [Indexed: 10/27/2022]
Abstract
M1 muscarinic receptors have long been identified as a potential therapeutic target for the treatment of cognitive impairment in Alzheimer's disease (AD). Our previous study has shown that M1 receptors promote membrane insertion and synaptic delivery of AMPA receptor GluA1 subunit. In this study, we sought to determine whether activation of M1 receptor would rescue the cognitive impairment in AD model mice through modulation of GluA1 subunit. For the mice injected with aggregated β-amyloid (Aβ) fragments to impair learning and memory, activation of M1 receptors could rescue it by reducing the latency to find the platform and spending more time in the target quadrant in the probe test in the Morris water maze. However, such an effect was ablated in mice with Ser845 residue of GluA1 mutated to alanine. Furthermore, the activation of M1 receptors enhanced the expression of GluA1 and its phosphorylation at Ser845 and drove GluA1 to incorporate with PSD95, a postsynaptic marker, in the hippocampi from Aβ-injected wild type mice but not from the mutant mice. Moreover, for 9-month-old APP/PS1 transgenic AD model mice, which may resemble the late AD, M1 receptor activation could not improve the cognitive impairment significantly. In addition, the enhancement of GluA1 expression and its phosphorylation at Ser845 were not observed in their hippocampi. Taken together, the study indicated that M1 receptor activation rescued the cognitive deficit through modulating the trafficking of GluA1-containing AMPA receptors and the therapeutics targeting M1 receptors should aim at mild AD or even pre-AD.
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Affiliation(s)
- Lan-Xue Zhao
- Department of Pharmacology and Chemical Biology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Mu-Wen Chen
- Department of Pharmacology and Chemical Biology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Yue Qian
- Department of Pharmacology and Chemical Biology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Qian-Hao Yang
- Department of Pharmacology and Chemical Biology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Yan-Hui Ge
- Department of Pharmacology and Chemical Biology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Hong-Zhuan Chen
- Institute of Interdisciplinary Integrative Biomedical Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201210, China.
| | - Yu Qiu
- Department of Pharmacology and Chemical Biology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.
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Modulation of the p75 neurotrophin receptor suppresses age-related basal forebrain cholinergic neuron degeneration. Sci Rep 2019; 9:5273. [PMID: 30918278 PMCID: PMC6437186 DOI: 10.1038/s41598-019-41654-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 02/08/2019] [Indexed: 11/19/2022] Open
Abstract
Age-related degeneration of basal forebrain cholinergic neurons (BFCNs) is linked to cognitive impairment. The p75 neurotrophin receptor (p75NTR) has been proposed to mediate neuronal degeneration in aging. Therefore, we tested the hypothesis that modifying p75NTR function would prevent or reverse aging-related neuronal degeneration using LM11A-31, a small molecule p75NTR modulator that downregulates degenerative and upregulates trophic receptor-associated signaling. Morphological analysis in mice showed loss of BFCN area detectable by 18 months of age. Oral administration of LM11A-31 from age 15 to 18 months resulted in a dose-related preservation of BFCN area and one month of treatment from 17 to 18 months also preserved cell area. To evaluate reversal of established neuronal atrophy, animals were treated from 21 to 25 months of age. Treatment was associated with an increase of cell size to a mean area larger than that observed at 18 months, accompanied by increases in mean MS/VDB neurite length, as well as increased cholinergic fiber density and synaptophysin pre-synaptic marker levels in the hippocampus. These findings support the idea that modulation of p75NTR activity can prevent and potentially reverse age-associated BFCN degeneration. Moreover, this may be achieved therapeutically with orally bioavailable agents such as LM11A-31.
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Karthick C, Nithiyanandan S, Essa MM, Guillemin GJ, Jayachandran SK, Anusuyadevi M. Time-dependent effect of oligomeric amyloid-β (1-42)-induced hippocampal neurodegeneration in rat model of Alzheimer's disease. Neurol Res 2018; 41:139-150. [PMID: 30453864 DOI: 10.1080/01616412.2018.1544745] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Alzheimer's disease (AD) is characterized with an abnormal deposition of insoluble amyloid-beta (Aβ) peptide plaques, tangles formation and synaptic dysfunction. These result in impaired functioning of neuronal circuits and alter the behavioral response owing to activation of neurotransmitter receptors. Recently, it has been implicated that Aβ influences N-methyl d-aspartate (NMDA) receptor activation in AD; however, the molecular mechanism underlying remains unclear. Thus, emerged specific aim to study the time-course effect of oligomeric Aβ(1-42) (oAβ1-42) on the mRNA expression of genes encoding NMDA and acetylcholine receptors in the rat model of AD. METHODS Aggregated forms of synthetic Aβ peptides were injected bilaterally into the intrahippocampal region of rat brain using stereotaxic surgery. Behavioral analysis was performed using eight-arm Radial Arm Maze task at the end of experimental period. Euthanized rat brain hippocampal tissue was used to study the mRNA expression of glutamatergic and cholinergic receptor using semiquantitative reverse transcription-polymerase chain reaction. RESULTS oAβ1-42 decreased the gene expression level of α7-nicotinic acetylcholine receptor and increased the mRNA expression of NMDA receptor 2A, and -2B subunits. In particular, oAβ1-42 aggregates increased the retention time and altered the behavioral response in rats after 15 days of injection. Further, amyloid-β1-42 are highly expressed in 15 days after postinjection in hippocampus of adult rats. CONCLUSION Acute exposure of oAβ1-42 modulated differential gene expression of glutamatergic and cholinergic receptors in hippocampus of adult rats and is duration dependent reflecting changes in hippocampal circuitry system underlying learning and memory impairments. ABBREVIATIONS AD: Alzheimer's disease, Aβ: amyloid-β; oAβ1-42: oligomeric amyloid-β 1-42 full length peptide; CAM: calmodulin; CNS: central nervous system; CR: Congo red; DG: dentate gyrus; EC: entorhinal cortex; HFIP: 1,1,1,3,3,3-hexafluoro-2-propanol; IBO: ibotenic acid; NMDA: N-methyl d-aspartate; NMDAR: N-methyl d-aspartate receptor; NR2A: N-methyl d-aspartate receptor 2A; NR2B: N-methyl d-aspartate receptor 2B; ACh: acetylcholine; α7-nAChR: α7-nicotinic acetylcholine receptor; PBS: phosphate buffered saline; RAM: Radial Arm Maze; ThT: thioflavin T.
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Affiliation(s)
- Chennakesavan Karthick
- a Molecular Gerontology Laboratory, Department of Biochemistry , School of Life Sciences, Bharathidasan University , Tiruchirappalli , India
| | - Saravanan Nithiyanandan
- a Molecular Gerontology Laboratory, Department of Biochemistry , School of Life Sciences, Bharathidasan University , Tiruchirappalli , India
| | - Musthafa Mohamed Essa
- b Department of Food Science and Nutrition , College of Agriculture and Marine Sciences, Sultan Qaboos University , Muscat , Oman
| | - Gilles J Guillemin
- c Neuroinflammation group, Faculty of Medicine and Health Sciences, Deb Bailey MND Research Laboratory , Macquaire University , Sydney , Australia
| | - Swaminathan K Jayachandran
- d Molecular Cardiology and Drug Discovery Laboratory, Department of Bioinformatics , School of Life Sciences, Bharathidasan University , Tiruchirappalli , India
| | - Muthuswamy Anusuyadevi
- a Molecular Gerontology Laboratory, Department of Biochemistry , School of Life Sciences, Bharathidasan University , Tiruchirappalli , India
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Weishaupt N, Liu Q, Shin S, Singh R, Agca Y, Agca C, Hachinski V, Whitehead SN. APP21 transgenic rats develop age-dependent cognitive impairment and microglia accumulation within white matter tracts. J Neuroinflammation 2018; 15:241. [PMID: 30153843 PMCID: PMC6114740 DOI: 10.1186/s12974-018-1273-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 08/09/2018] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Most of the animal models commonly used for preclinical research into Alzheimer's disease (AD) largely fail to address the pathophysiology, including the impact of known risk factors, of the widely diagnosed sporadic form of the disease. Here, we use a transgenic rat (APP21) that does not develop AD-like pathology spontaneously with age, but does develop pathology following vascular stress. To further the potential of this novel rat model as a much-needed pre-clinical animal model of sporadic AD, we characterize APP21 transgenic rats behaviorally and histologically up to 19 months of age. METHODS The open field test was used as a measure of activity; and the Morris water maze was used to assess learning, memory, and strategy shift. Neuronal loss and microglia activation were also assessed throughout the brain. RESULTS APP21 transgenic rats showed deficits in working memory from an early age, yet memory recall performance after 24 and 72 h was equal to that of wildtype rats and did not deteriorate with age. A deficit in strategy shift was observed at 19 months of age in APP21 transgenic rats compared to Fischer wildtype rats. Histologically, APP21 transgenic rats demonstrated accelerated white matter inflammation compared to wildtype rats, but interestingly no differences in neuron loss were observed. CONCLUSIONS The combined presence of white matter pathology and executive function deficits mirrored what is often found in patients with mild cognitive impairment or early dementia, and suggests that this rat model will be useful for translationally meaningful studies into the development and prevention of sporadic AD. The presence of widespread white matter inflammation as the only observed pathological correlate for cognitive deficits raises new questions as to the role of neuroinflammation in cognitive decline.
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Affiliation(s)
- Nina Weishaupt
- Vulnerable Brain Laboratory, Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, 1151 Richmond St, London, Ontario N6A 5C1 Canada
| | - Qingfan Liu
- Vulnerable Brain Laboratory, Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, 1151 Richmond St, London, Ontario N6A 5C1 Canada
| | - Sheojung Shin
- Vulnerable Brain Laboratory, Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, 1151 Richmond St, London, Ontario N6A 5C1 Canada
| | - Ramandeep Singh
- Vulnerable Brain Laboratory, Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, 1151 Richmond St, London, Ontario N6A 5C1 Canada
| | - Yuksel Agca
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO USA
| | - Cansu Agca
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO USA
| | - Vladimir Hachinski
- Clinical Neurological Sciences, London Health Sciences Centre, University of Western Ontario, London, Ontario N6A 5A5 Canada
| | - Shawn Narain Whitehead
- Vulnerable Brain Laboratory, Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, 1151 Richmond St, London, Ontario N6A 5C1 Canada
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Ronowska A, Szutowicz A, Bielarczyk H, Gul-Hinc S, Klimaszewska-Łata J, Dyś A, Zyśk M, Jankowska-Kulawy A. The Regulatory Effects of Acetyl-CoA Distribution in the Healthy and Diseased Brain. Front Cell Neurosci 2018; 12:169. [PMID: 30050410 PMCID: PMC6052899 DOI: 10.3389/fncel.2018.00169] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 05/31/2018] [Indexed: 12/25/2022] Open
Abstract
Brain neurons, to support their neurotransmitter functions, require a several times higher supply of glucose than non-excitable cells. Pyruvate, the end product of glycolysis, through pyruvate dehydrogenase complex reaction, is a principal source of acetyl-CoA, which is a direct energy substrate in all brain cells. Several neurodegenerative conditions result in the inhibition of pyruvate dehydrogenase and decrease of acetyl-CoA synthesis in mitochondria. This attenuates metabolic flux through TCA in the mitochondria, yielding energy deficits and inhibition of diverse synthetic acetylation reactions in all neuronal sub-compartments. The acetyl-CoA concentrations in neuronal mitochondrial and cytoplasmic compartments are in the range of 10 and 7 μmol/L, respectively. They appear to be from 2 to 20 times lower than acetyl-CoA Km values for carnitine acetyltransferase, acetyl-CoA carboxylase, aspartate acetyltransferase, choline acetyltransferase, sphingosine kinase 1 acetyltransferase, acetyl-CoA hydrolase, and acetyl-CoA acetyltransferase, respectively. Therefore, alterations in acetyl-CoA levels alone may significantly change the rates of metabolic fluxes through multiple acetylation reactions in brain cells in different physiologic and pathologic conditions. Such substrate-dependent alterations in cytoplasmic, endoplasmic reticulum or nuclear acetylations may directly affect ACh synthesis, protein acetylations, and gene expression. Thereby, acetyl-CoA may regulate the functional and adaptative properties of neuronal and non-neuronal brain cells. The excitotoxicity-evoked intracellular zinc excess hits several intracellular targets, yielding the collapse of energy balance and impairment of the functional and structural integrity of postsynaptic cholinergic neurons. Acute disruption of brain energy homeostasis activates slow accumulation of amyloid-β1-42 (Aβ). Extra and intracellular oligomeric deposits of Aβ affect diverse transporting and signaling pathways in neuronal cells. It may combine with multiple neurotoxic signals, aggravating their detrimental effects on neuronal cells. This review presents evidences that changes of intraneuronal levels and compartmentation of acetyl-CoA may contribute significantly to neurotoxic pathomechanisms of different neurodegenerative brain disorders.
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Affiliation(s)
- Anna Ronowska
- Department of Laboratory Medicine, Faculty of Medicine, Medical University of Gdańsk, Gdańsk, Poland
| | - Andrzej Szutowicz
- Department of Laboratory Medicine, Faculty of Medicine, Medical University of Gdańsk, Gdańsk, Poland
| | - Hanna Bielarczyk
- Department of Laboratory Medicine, Faculty of Medicine, Medical University of Gdańsk, Gdańsk, Poland
| | - Sylwia Gul-Hinc
- Department of Laboratory Medicine, Faculty of Medicine, Medical University of Gdańsk, Gdańsk, Poland
| | - Joanna Klimaszewska-Łata
- Department of Laboratory Medicine, Faculty of Medicine, Medical University of Gdańsk, Gdańsk, Poland
| | - Aleksandra Dyś
- Department of Laboratory Medicine, Faculty of Medicine, Medical University of Gdańsk, Gdańsk, Poland
| | - Marlena Zyśk
- Department of Laboratory Medicine, Faculty of Medicine, Medical University of Gdańsk, Gdańsk, Poland
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11
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Paquet M, Cerasuolo JO, Thorburn V, Fridman S, Alsubaie R, Lopes RD, Cipriano LE, Salamone P, Melling CWJ, Khan AR, Sedeño L, Fang J, Drangova M, Montero-Odasso M, Mandzia J, Khaw AV, Racosta JM, Paturel J, Samoilov L, Stirling D, Balint B, Jaremek V, Koschinsky ML, Boffa MB, Summers K, Ibañez A, Mrkobrada M, Saposnik G, Kimpinski K, Whitehead SN, Sposato LA. Pathophysiology and Risk of Atrial Fibrillation Detected after Ischemic Stroke (PARADISE): A Translational, Integrated, and Transdisciplinary Approach. J Stroke Cerebrovasc Dis 2017; 27:606-619. [PMID: 29141778 DOI: 10.1016/j.jstrokecerebrovasdis.2017.09.038] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/22/2017] [Accepted: 09/24/2017] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND It has been hypothesized that ischemic stroke can cause atrial fibrillation. By elucidating the mechanisms of neurogenically mediated paroxysmal atrial fibrillation, novel therapeutic strategies could be developed to prevent atrial fibrillation occurrence and perpetuation after stroke. This could result in fewer recurrent strokes and deaths, a reduction or delay in dementia onset, and in the lessening of the functional, structural, and metabolic consequences of atrial fibrillation on the heart. METHODS The Pathophysiology and Risk of Atrial Fibrillation Detected after Ischemic Stroke (PARADISE) study is an investigator-driven, translational, integrated, and transdisciplinary initiative. It comprises 3 complementary research streams that focus on atrial fibrillation detected after stroke: experimental, clinical, and epidemiological. The experimental stream will assess pre- and poststroke electrocardiographic, autonomic, anatomic (brain and heart pathology), and inflammatory trajectories in an animal model of selective insular cortex ischemic stroke. The clinical stream will prospectively investigate autonomic, inflammatory, and neurocognitive changes among patients diagnosed with atrial fibrillation detected after stroke by employing comprehensive and validated instruments. The epidemiological stream will focus on the demographics, clinical characteristics, and outcomes of atrial fibrillation detected after stroke at the population level by means of the Ontario Stroke Registry, a prospective clinical database that comprises over 23,000 patients with ischemic stroke. CONCLUSIONS PARADISE is a translational research initiative comprising experimental, clinical, and epidemiological research aimed at characterizing clinical features, the pathophysiology, and outcomes of neurogenic atrial fibrillation detected after stroke.
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Affiliation(s)
- Maryse Paquet
- Stroke, Dementia and Heart Disease Laboratory, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Joshua O Cerasuolo
- Stroke, Dementia and Heart Disease Laboratory, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Victoria Thorburn
- Stroke, Dementia and Heart Disease Laboratory, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Vulnerable Brain Laboratory, Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Sebastian Fridman
- Department of Clinical Neurological Sciences, London Health Sciences Centre, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Rasha Alsubaie
- Department of Clinical Neurological Sciences, London Health Sciences Centre, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Renato D Lopes
- Division of Cardiology, Department of Medicine, Duke University Medical Center, Durham, North Carolina
| | - Lauren E Cipriano
- Department of Epidemiology & Biostatistics, Schulich School of Medicine & Dentistry, Ivey Business School, Western University, London, Ontario, Canada
| | - Paula Salamone
- Laboratory of Experimental, Psychology and Neuroscience (LPEN), Institute of Cognitive and Translational Neuroscience (INCyT), INECO Foundation, Favaloro University; National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
| | - C W James Melling
- School of Kinesiology, Faculty of Health Sciences, Western University, London, ON, Canada
| | - Ali R Khan
- Robarts Research Institute, Department of Medical Biophysics & Medical Imaging, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Lucas Sedeño
- Laboratory of Experimental, Psychology and Neuroscience (LPEN), Institute of Cognitive and Translational Neuroscience (INCyT), INECO Foundation, Favaloro University; National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
| | - Jiming Fang
- Institute for Clinical Evaluative Sciences (ICES), Toronto, Ontario, Canada
| | - Maria Drangova
- Robarts Research Institute, Department of Medical Biophysics & Medical Imaging, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Manuel Montero-Odasso
- Gait and Brain Lab, Parkwood Institute and Lawson Health Research Institute, London, Ontario, Canada; Division of Geriatric Medicine and Dentistry, Department of Medicine, Schulich School of Medicine, Western University, London, Ontario, Canada; Department of Epidemiology and Biostatistics, Schulich School of Medicine, Western University, London, Ontario, Canada
| | - Jennifer Mandzia
- Department of Clinical Neurological Sciences, London Health Sciences Centre, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Alexander V Khaw
- Department of Clinical Neurological Sciences, London Health Sciences Centre, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Juan M Racosta
- Autonomic Disorders Laboratory, Clinical Neurological Sciences Department, Schulich School of Medicine & Dentistry, London Health Sciences Center, Western University, London, ON, Canada
| | - Justin Paturel
- Autonomic Disorders Laboratory, Clinical Neurological Sciences Department, Schulich School of Medicine & Dentistry, London Health Sciences Center, Western University, London, ON, Canada
| | - Lucy Samoilov
- Stroke, Dementia and Heart Disease Laboratory, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Devin Stirling
- Stroke, Dementia and Heart Disease Laboratory, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Brittany Balint
- Stroke, Dementia and Heart Disease Laboratory, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Vulnerable Brain Laboratory, Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Victoria Jaremek
- Stroke, Dementia and Heart Disease Laboratory, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Vulnerable Brain Laboratory, Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Marlys L Koschinsky
- Robarts Research Institute, Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
| | - Michael B Boffa
- Department of Biochemistry, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
| | - Kelly Summers
- Department of Microbiology and Immunology, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
| | - Agustín Ibañez
- Laboratory of Experimental, Psychology and Neuroscience (LPEN), Institute of Cognitive and Translational Neuroscience (INCyT), INECO Foundation, Favaloro University, Buenos Aires, Argentina; National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina; Universidad Autónoma del Caribe, Barranquilla, ColombiaCenter for Social and Cognitive Neuroscience (CSCN), School of Psychology, Universidad Adolfo Ibáñez, Santiago, Chile; Centre of Excellence in Cognition and its Disorders, Australian Research Council (ACR), Macquarie University, Sydney, New South Wale, Australia
| | - Marko Mrkobrada
- Department of Medicine, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada
| | - Gustavo Saposnik
- Stroke Outcomes Research Center, Division of Neurology, Department of Medicine, St. Michael's Hospital and Institute of Health Policy, Management and Evaluation, Faculty of Medicine, University of Toronto, Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada; Li Ka Shing Knowledge Institute, Toronto, Ontario, Canada
| | - Kurt Kimpinski
- Autonomic Disorders Laboratory, Clinical Neurological Sciences Department, Schulich School of Medicine & Dentistry, London Health Sciences Center, Western University, London, ON, Canada
| | - Shawn N Whitehead
- Vulnerable Brain Laboratory, Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Luciano A Sposato
- Stroke, Dementia and Heart Disease Laboratory, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Department of Clinical Neurological Sciences at London Health Sciences Centre, Department of Epidemiology and Biostatistics, Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.
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Deibel S, Weishaupt N, Regis A, Hong N, Keeley R, Balog R, Bye C, Himmler S, Whitehead S, McDonald R. Subtle learning and memory impairment in an idiopathic rat model of Alzheimer's disease utilizing cholinergic depletions and β-amyloid. Brain Res 2016; 1646:12-24. [DOI: 10.1016/j.brainres.2016.05.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 05/16/2016] [Accepted: 05/17/2016] [Indexed: 02/02/2023]
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Assessing the Effects of Acute Amyloid β Oligomer Exposure in the Rat. Int J Mol Sci 2016; 17:ijms17091390. [PMID: 27563885 PMCID: PMC5037670 DOI: 10.3390/ijms17091390] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Revised: 08/16/2016] [Accepted: 08/18/2016] [Indexed: 11/28/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common form of dementia, yet there are no therapeutic treatments that can either cure or delay its onset. Currently, the pathogenesis of AD is still uncertain, especially with respect to how the disease develops from a normal healthy brain. Amyloid β oligomers (AβO) are highly neurotoxic proteins and are considered potential initiators to the pathogenesis of AD. Rat brains were exposed to AβO via bilateral intracerebroventricular injections. Rats were then euthanized at either 1, 3, 7 or 21-days post surgery. Rat behavioural testing was performed using the Morris water maze and open field tests. Post-mortem brain tissue was immunolabelled for Aβ, microglia, and cholinergic neurons. Rats exposed to AβO showed deficits in spatial learning and anxiety-like behaviour. Acute positive staining for Aβ was only observed in the corpus callosum surrounding the lateral ventricles. AβO exposed rat brains also showed a delayed increase in activated microglia within the corpus callosum and a decreased number of cholinergic neurons within the basal forebrain. Acute exposure to AβO resulted in mild learning and memory impairments with co-concomitant white matter pathology within the corpus callosum and cholinergic cell loss within the basal forebrain. Results suggest that acute exposure to AβO in the rat may be a useful tool in assessing the early phases for the pathogenesis of AD.
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Chronic Ampakine Treatments Stimulate Dendritic Growth and Promote Learning in Middle-Aged Rats. J Neurosci 2016; 36:1636-46. [PMID: 26843645 DOI: 10.1523/jneurosci.3157-15.2016] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
UNLABELLED Positive allosteric modulators of AMPA-type glutamate receptors (ampakines) have been shown to rescue synaptic plasticity and reduce neuropathology in rodent models of cognitive disorders. Here we tested whether chronic ampakine treatment offsets age-related dendritic retraction in middle-aged (MA) rats. Starting at 10 months of age, rats were housed in an enriched environment and given daily treatment with a short half-life ampakine or vehicle for 3 months. Dendritic branching and spine measures were collected from 3D reconstructions of Lucifer yellow-filled CA1 pyramidal cells. There was a substantial loss of secondary branches, relative to enriched 2.5-month-old rats, in apical and basal dendritic fields of vehicle-treated, but not ampakine-treated, 13-month-old rats. Baseline synaptic responses in CA1 were only subtly different between the two MA groups, but long-term potentiation was greater in ampakine-treated rats. Unsupervised learning of a complex environment was used to assess treatment effects on behavior. Vehicle- and drug-treated rats behaved similarly during a first 30 min session in the novel environment but differed markedly on subsequent measures of long-term memory. Markov sequence analysis uncovered a clear increase in the predictability of serial movements between behavioral sessions 2 and 3 in the ampakine, but not vehicle, group. These results show that a surprising degree of dendritic retraction occurs by middle age and that this can be mostly offset by pharmacological treatments without evidence for unwanted side effects. The functional consequences of rescue were prominent with regard to memory but also extended to self-organization of behavior. SIGNIFICANCE STATEMENT Brain aging is characterized by a progressive loss of dendritic arbors and the emergence of impairments to learning-related synaptic plasticity. The present studies show that dendritic losses are evident by middle age despite housing in an enriched environment and can be mostly reversed by long-term, oral administration of a positive allosteric modulator of AMPA-type glutamate receptors. Dendritic recovery was accompanied by improvements to both synaptic plasticity and the encoding of long-term memory of a novel, complex environment. Because the short half-life compound had no evident negative effects, the results suggest a plausible strategy for treating age-related neuronal deterioration.
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15
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Nell HJ, Au JL, Giordano CR, Terlecky SR, Walton PA, Whitehead SN, Cechetto DF. Targeted Antioxidant, Catalase-SKL, Reduces Beta-Amyloid Toxicity in the Rat Brain. Brain Pathol 2016; 27:86-94. [PMID: 26919450 DOI: 10.1111/bpa.12368] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 02/08/2016] [Indexed: 12/21/2022] Open
Abstract
Accumulation of beta-amyloid (Aβ) in the brain has been implicated as a major contributor to the cellular pathology and cognitive impairment observed in Alzheimer's disease. Beta-amyloid may exert its toxic effects by increasing reactive oxygen species and neuroinflammation in the brain. This study set out to investigate whether a genetically engineered derivative of the peroxisomal antioxidant enzyme catalase (CAT-SKL), is able to reduce the toxicity induced by intracerebroventricular injection of Aβ25-35 in the mature rat brain. Histopathological and immunohistochemical analyses were used to evaluate neuroinflammation, and neuronal loss. Spatial learning and reference memory was assessed using the Morris water maze. CAT-SKL treatment was able to reduce the pathology induced by Aβ25-35 toxicity by significantly decreasing microglia activation in the basal forebrain and thalamus, and reducing cholinergic loss in the basal forebrain. Aβ25-35 animals showed deficits in long-term reference memory in the Morris water maze, while Aβ25-35 animals treated with CAT-SKL did not demonstrate long-term memory impairments. This preclinical data provides support for the use of CAT-SKL in reducing neuroinflammation and long-term reference memory deficits induced by Aβ25-35.
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Affiliation(s)
- Hayley J Nell
- Department of Anatomy and Cell Biology, University of Western Ontario, London, ON, N6A 5C1, Canada
| | - Jennifer L Au
- Department of Anatomy and Cell Biology, University of Western Ontario, London, ON, N6A 5C1, Canada
| | - Courtney R Giordano
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI, 48201
| | - Stanley R Terlecky
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI, 48201
| | - Paul A Walton
- Department of Anatomy and Cell Biology, University of Western Ontario, London, ON, N6A 5C1, Canada
| | - Shawn N Whitehead
- Department of Anatomy and Cell Biology, University of Western Ontario, London, ON, N6A 5C1, Canada
| | - David F Cechetto
- Department of Anatomy and Cell Biology, University of Western Ontario, London, ON, N6A 5C1, Canada
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PI3K/AKT/mTOR/p70S6K Pathway Is Involved in Aβ25-35-Induced Autophagy. BIOMED RESEARCH INTERNATIONAL 2015; 2015:161020. [PMID: 26583091 PMCID: PMC4637023 DOI: 10.1155/2015/161020] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 07/17/2015] [Accepted: 08/04/2015] [Indexed: 02/06/2023]
Abstract
Disruption or deregulation of the autophagy system has been implicated in neurodegenerative disorders such as Alzheimer's disease (AD). Aβ plays an important role in this autophagic system. In many cases, autophagy is regulated by the phosphatidylinositol 3-phosphate kinase/AKT/mammalian target of rapamycin/p70 ribosomal protein S6 kinase (PI3K/AKT/mTOR/p70S6K) signaling pathway. However, whether this signaling pathway is involved in Aβ-induced autophagy in neuronal cells is not known. Here, we studied whether Aβ25-35 induces autophagy in HT22 cells and C57 mice and investigated whether PI3K is involved in the autophagy induction. We found that Aβ25-35 inhibited HT22 cell viability in a dose- and time-dependent manner. Aβ25-35 induced autophagosome formation, the conversion of microtubule-associated protein light chain 3 (LC3), and the suppression of the mTOR pathway both in vitro and in vivo. Furthermore, Aβ25-35 impaired the learning abilities of C57 mice. Our study suggests that Aβ25-35 induces autophagy and the PI3K/AKT/mTOR/p70S6K pathway is involved in the process, which improves our understanding of the pathogenesis of AD and provides an additional model for AD research.
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