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Rajah Kumaran K, Yunusa S, Perimal E, Wahab H, Müller CP, Hassan Z. Insights into the Pathophysiology of Alzheimer's Disease and Potential Therapeutic Targets: A Current Perspective. J Alzheimers Dis 2023; 91:507-530. [PMID: 36502321 DOI: 10.3233/jad-220666] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The aging population increases steadily because of a healthy lifestyle and medical advancements in healthcare. However, Alzheimer's disease (AD) is becoming more common and problematic among older adults. AD-related cases show an increasing trend annually, and the younger age population may also be at risk of developing this disorder. AD constitutes a primary form of dementia, an irreversible and progressive brain disorder that steadily damages cognitive functions and the ability to perform daily tasks. Later in life, AD leads to death as a result of the degeneration of specific brain areas. Currently, the cause of AD is poorly understood, and there is no safe and effective therapeutic agent to cure or slow down its progression. The condition is entirely preventable, and no study has yet demonstrated encouraging findings in terms of treatment. Identifying this disease's pathophysiology can help researchers develop safe and efficient therapeutic strategies to treat this ailment. This review outlines and discusses the pathophysiology that resulted in the development of AD including amyloid-β plaques, tau neurofibrillary tangles, neuroinflammation, oxidative stress, cholinergic dysfunction, glutamate excitotoxicity, and changes in neurotrophins level may sound better based on the literature search from Scopus, PubMed, ScienceDirect, and Google Scholar. Potential therapeutic strategies are discussed to provide more insights into AD mechanisms by developing some possible pharmacological agents for its treatment.
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Affiliation(s)
- Kesevan Rajah Kumaran
- Malaysian Institute of Pharmaceuticals and Nutraceuticals, National Institutes of Biotechnology Malaysia, Halaman Bukit Gambir, Gelugor, Pulau Pinang, Malaysia
| | - Suleiman Yunusa
- Centre for Drug Research, Universiti Sains Malaysia, Penang, Malaysia.,Department of Pharmacology, Bauchi State University Gadau, Bauchi State, Nigeria
| | - Enoch Perimal
- Curtin Medical School, Curtin University, Bentley, Western Australia, Australia.,Department of Biomedical Science, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Malaysia
| | - Habibah Wahab
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, Penang, Malaysia
| | - Christian P Müller
- Centre for Drug Research, Universiti Sains Malaysia, Penang, Malaysia.,Section of Addiction Medicine, Department of Psychiatry and Psychotherapy, University Clinic, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - Zurina Hassan
- Centre for Drug Research, Universiti Sains Malaysia, Penang, Malaysia.,Section of Addiction Medicine, Department of Psychiatry and Psychotherapy, University Clinic, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
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2
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Combined long-term enriched environment and caffeine supplementation improve memory function in C57Bl6 mice. Eur Arch Psychiatry Clin Neurosci 2023; 273:269-281. [PMID: 35676374 PMCID: PMC9958139 DOI: 10.1007/s00406-022-01431-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 05/15/2022] [Indexed: 11/03/2022]
Abstract
Regular physical activity has been associated with healthy brain aging, reflected by beneficial effects on cognition and learning and memory. Nutritional supplements such as caffeine have been shown to act as cognitive enhancers and may possess neuroprotective properties. Interestingly, caffeine also improves athletic capabilities and is widely used by athletes because of its performance-enhancing effect, while information on potential additive beneficial effects of physical activity and caffeine on cognitive performance is scarce. In the present study, the effects of caffeine supplementation in combination with prolonged physical and cognitive stimulation in the form of the enriched environment (EE) housing for a duration of 4 months were analyzed. We demonstrate that caffeine supplementation together with prolonged environmental enrichment led to enhanced memory function, resulting in improved recognition and spatial working memory in behavioral paradigms such as the novel object recognition task or the Morris water maze in C57Bl6 wild-type mice. Mice housed under EE conditions showed increased gene expression levels of brain-derived neurotrophic factor (BDNF) in the hippocampus. The present findings underscore the potential impact of continuous physical activity in the prevention of age-related cognitive decline and may offer new options for combinatorial approaches.
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Nagano T, Tsuda N, Fujimura K, Ikezawa Y, Higashi Y, Kimura SH. Prostaglandin E 2 increases the expression of cyclooxygenase-2 in cultured rat microglia. J Neuroimmunol 2021; 361:577724. [PMID: 34610503 DOI: 10.1016/j.jneuroim.2021.577724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 09/17/2021] [Accepted: 09/19/2021] [Indexed: 12/21/2022]
Abstract
Prostaglandin E2 (PGE2) plays pivotal roles in controlling microglial activation with the EP2 receptor, a PGE2 receptor subtype. Activated microglia are often reported to increase cyclooxygenase (COX)-2 expression, followed by PGE2 production, but it is unclear whether extracellular PGE2 is involved in microglial PGE2 synthesis. In the present study, we report that PGE2 increases COX-2 protein in microglia. In a culture system, PGE2 at 10-6 M for 3 h increased COX-2 and microsomal PGE synthase (mPGES)-1 mRNA levels, and reduced mPGES-2, but did not affect COX-1 or cytosolic PGE synthase (cPGES) in microglia. PGE2 at 10-6 M for 3 h also increased the COX-2 protein level, but did not affect COX-1, mPGES-1, mPGES-2, or cPGES. An EP2 agonist, ONO-AE1-259-01, also increased COX-2 and mPGES-1 mRNA levels, and reduced mPGES-2, but did not affect COX-1 or cPGES, whereas an EP1 agonist, ONO-DI-004, an EP3 agonist, ONO-AE-248, and an EP4 agonist, ONO-AE1-329, had no effect. Similar to PGE2, ONO-AE1-259-01 increased the COX-2 protein level, but did not affect COX-1, mPGES-1, mPGES-2, or cPGES. In addition, the effects of PGE2 were inhibited by an EP2 antagonist, PF-04418948, but not by an EP1 antagonist, ONO-8713, an EP3 antagonist, ONO-AE3-240, or an EP4 antagonist, ONO-AE3-208, at 10-6 M. On the other hand, lipopolysaccharide (LPS) increased PGE2 production, but the LPS-induced PGE2 production was not affected by ONO-8713, PF-04418948, ONO-AE3-240, or ONO-AE3-208. These results indicate that PGE2 increases COX-2 protein in microglia through the EP2 receptor supporting the idea that extracellular PGE2 has a triggering aspect for microglial activation.
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Affiliation(s)
- Takayuki Nagano
- Department of Pharmacology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan.
| | - Naohiko Tsuda
- Department of Pharmacology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Kenichi Fujimura
- Department of Pharmacology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Yuji Ikezawa
- Department of Pharmacology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Yuki Higashi
- Department of Pharmacology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Shinya H Kimura
- Department of Pharmacology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
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Shi Y, Zhang L, Gao X, Zhang J, Ben Abou M, Liang G, Meng Q, Hepner A, Eckenhoff MF, Wei H. Intranasal Dantrolene as a Disease-Modifying Drug in Alzheimer 5XFAD Mice. J Alzheimers Dis 2021; 76:1375-1389. [PMID: 32623395 PMCID: PMC7505009 DOI: 10.3233/jad-200227] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Background/Objective: This study compares the effectiveness and safety of intranasal versus subcutaneous administration of dantrolene in 5XFAD Alzheimer’s disease (AD) mice. Methods: 5XFAD and wild type (WT) B6SJLF1/J mice were treated with intranasal or subcutaneous dantrolene (5 mg/kg, 3×/wk), or vehicle. The early (ETG) and late (LTG) treatment groups began treatment at 2 or 6 months of age, respectively, and both treatment groups finished at12 months of age. Behavior was assessed for olfaction (buried food test), motor function (rotarod), and cognition (fear conditioning, Morris water maze). Liver histology (H & E staining) and function, synaptic proteins, and brain amyloid immunohistochemistry were examined. Plasma and brain dantrolene concentrations were determined in a separate cohort after intranasal or subcutaneous administration. Results: Intranasal dantrolene achieved higher brain and lower plasma concentrations than subcutaneous administration. Dantrolene administration at both approaches significantly improved hippocampal-dependent and -independent memory in the ETG, whereas only intranasal dantrolene improved cognition in the LTG. Dantrolene treatment had no significant change in the amyloid burden or synaptic proteins and no significant side effects on mortality, olfaction, motor, or liver functions in 5XFAD mice. Intranasal dantrolene treatment significantly ameliorated memory loss when it was started either before or after the onset of AD symptoms in 5XFAD mice. Conclusions: The long-term intranasal administration of dantrolene had therapeutic effects on memory compared to the subcutaneous approach even started after onset of AD symptoms, suggesting use as a disease-modifying drug, without significant effects on amyloid plaques, side effects, or mortality.
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Affiliation(s)
- Yun Shi
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Department of Anesthesiology, Children's Hospital of Fudan University, Shanghai, China
| | - Lei Zhang
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Department of Anesthesiology, People's Hospital of Beijing Daxing District, Beijing, China
| | - Xue Gao
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Department of Anesthesiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Jing Zhang
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Department of Anesthesiology, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
| | - Matan Ben Abou
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Ge Liang
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Qingcheng Meng
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Adrian Hepner
- Eagle Pharmaceuticals, Inc., Woodcliff Lake, NJ, USA
| | - Maryellen F Eckenhoff
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Huafeng Wei
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Nakai T, Yamada K, Mizoguchi H. Alzheimer's Disease Animal Models: Elucidation of Biomarkers and Therapeutic Approaches for Cognitive Impairment. Int J Mol Sci 2021; 22:ijms22115549. [PMID: 34074018 PMCID: PMC8197360 DOI: 10.3390/ijms22115549] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 05/21/2021] [Indexed: 12/12/2022] Open
Abstract
Alzheimer’s disease (AD) is an age-related and progressive neurodegenerative disorder. It is widely accepted that AD is mainly caused by the accumulation of extracellular amyloid β (Aβ) and intracellular neurofibrillary tau tangles. Aβ begins to accumulate years before the onset of cognitive impairment, suggesting that the benefit of currently available interventions would be greater if they were initiated in the early phases of AD. To understand the mechanisms of AD pathogenesis, various transgenic mouse models with an accelerated accumulation of Aβ and tau tangles have been developed. However, none of these models exhibit all pathologies present in human AD. To overcome these undesirable phenotypes, APP knock-in mice, which were presented with touchscreen-based tasks, were developed to better evaluate the efficacy of candidate therapeutics in mouse models of early-stage AD. This review assesses several AD mouse models from the aspect of biomarkers and cognitive impairment and discusses their potential as tools to provide novel AD therapeutic approaches.
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Affiliation(s)
- Tsuyoshi Nakai
- Department of Neuropsychopharmacology and Hospital Pharmacy, Nagoya University Graduate School of Medicine, Nagoya 466-8560, Japan; (T.N.); (K.Y.)
| | - Kiyofumi Yamada
- Department of Neuropsychopharmacology and Hospital Pharmacy, Nagoya University Graduate School of Medicine, Nagoya 466-8560, Japan; (T.N.); (K.Y.)
| | - Hiroyuki Mizoguchi
- Department of Neuropsychopharmacology and Hospital Pharmacy, Nagoya University Graduate School of Medicine, Nagoya 466-8560, Japan; (T.N.); (K.Y.)
- Medical Interactive Research and Academia Industry Collaboration Center, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan
- Correspondence: ; Tel.: +81-52-744-2674; Fax: +81-52-744-2979
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Manji Z, Rojas A, Wang W, Dingledine R, Varvel NH, Ganesh T. 5xFAD Mice Display Sex-Dependent Inflammatory Gene Induction During the Prodromal Stage of Alzheimer's Disease. J Alzheimers Dis 2020; 70:1259-1274. [PMID: 31322556 DOI: 10.3233/jad-180678] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Alzheimer's disease (AD) pathology consists of extracellular deposits of amyloid-β peptides (Aβ) and intracellular neurofibrillary tangles. These pathological alterations are accompanied by a neuroinflammatory response consisting of increased expression of inflammatory mediators. An anti-inflammatory strategy designed to prevent or delay the development of AD would benefit from knowing when neuroinflammation appears in the transgenic models during prodromal disease stages relative to Aβ pathology. We investigated the expression patterns of inflammatory mediators in the brain of 5xFAD mice in comparison to development of Aβ deposition. Expression changes in inflammatory mediators and glial markers are more robust in female mice starting at three months of age, in contrast to males in which there is no clear trend through five months. Female and male 5xFAD mice also displayed an age-dependent increase in cortical Aβ deposition congruent with neuroinflammation. Thus, in the 5xFAD mouse model of AD, administration of an anti-inflammatory agent would be most efficacious when administered before three months of age.
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Affiliation(s)
- Zahra Manji
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Asheebo Rojas
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Wenyi Wang
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Raymond Dingledine
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Nicholas H Varvel
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Thota Ganesh
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, USA
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Franke TN, Irwin C, Bayer TA, Brenner W, Beindorff N, Bouter C, Bouter Y. In vivo Imaging With 18F-FDG- and 18F-Florbetaben-PET/MRI Detects Pathological Changes in the Brain of the Commonly Used 5XFAD Mouse Model of Alzheimer's Disease. Front Med (Lausanne) 2020; 7:529. [PMID: 33043029 PMCID: PMC7522218 DOI: 10.3389/fmed.2020.00529] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 07/27/2020] [Indexed: 12/14/2022] Open
Abstract
Imaging biomarkers of Alzheimer's disease (AD) that are able to detect molecular changes in vivo and transgenic animal models mimicking AD pathologies are essential for the evaluation of new therapeutic strategies. Positron-emission tomography (PET) using either 18F-Fluorodeoxyglucose (18F-FDG) or amyloid-tracers is a well-established, non-invasive tool in the clinical diagnostics of AD assessing two major pathological hallmarks. 18F-FDG-PET is able to detect early changes in cerebral glucose metabolism and amyloid-PET shows cerebral amyloid load. However, the suitability of 18F-FDG- and amyloid-PET in the widely used 5XFAD mouse model of AD is unclear as only a few studies on the use of PET biomarkers are available showing some conflicting results. The aim of this study was the evaluation of 18F-FDG-PET and amyloid-PET in 5XFAD mice in comparison to neurological deficits and neuropathological changes. Seven- and 12-month-old male 5XFAD mice showed a significant reduction in brain glucose metabolism in 18F-FDG-PET and amyloid-PET with 18F-Florbetaben demonstrated an increased cerebral amyloid deposition (n = 4-6 per group). Deficits in spatial reference memory were detected in 12-month-old 5XFAD mice in the Morris Water Maze (n = 10-12 per group). Furthermore, an increased plaque load and gliosis could be proven immunohistochemically in 5XFAD mice (n = 4-6 per group). PET biomarkers 18F-FDG and 18F-Florbetaben detected cerebral hypometabolism and increased plaque load even before the onset of severe memory deficits. Therefore, the 5XFAD mouse model of AD is well-suited for in vivo monitoring of AD pathologies and longitudinal testing of new therapeutic approaches.
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Affiliation(s)
- Timon N Franke
- Department of Psychiatry and Psychotherapy, University Medical Center Göttingen (UMG), Georg-August-University, Göttingen, Germany
| | - Caroline Irwin
- Department of Psychiatry and Psychotherapy, University Medical Center Göttingen (UMG), Georg-August-University, Göttingen, Germany
| | - Thomas A Bayer
- Department of Psychiatry and Psychotherapy, University Medical Center Göttingen (UMG), Georg-August-University, Göttingen, Germany
| | - Winfried Brenner
- Department of Nuclear Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Nicola Beindorff
- Berlin Experimental Radionuclide Imaging Center (BERIC), Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Caroline Bouter
- Department of Nuclear Medicine, University Medical Center Göttingen (UMG), Georg-August-University, Göttingen, Germany
| | - Yvonne Bouter
- Department of Psychiatry and Psychotherapy, University Medical Center Göttingen (UMG), Georg-August-University, Göttingen, Germany
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Caspase-6 Knockout in the 5xFAD Model of Alzheimer's Disease Reveals Favorable Outcome on Memory and Neurological Hallmarks. Int J Mol Sci 2020; 21:ijms21031144. [PMID: 32050445 PMCID: PMC7037950 DOI: 10.3390/ijms21031144] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/05/2020] [Accepted: 02/07/2020] [Indexed: 12/15/2022] Open
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder and is the most common form of dementia in the elderly. Caspases, a family of cysteine proteases, are major mediators of apoptosis and inflammation. Caspase-6 is considered to be an up-stream modulator of AD pathogenesis as active caspase-6 is abundant in neuropil threads, neuritic plaques, and neurofibrillary tangles of AD brains. In order to further elucidate the role of caspase-6 activity in the pathogenesis of AD, we produced a double transgenic mouse model, combining the 5xFAD mouse model of AD with caspase-6 knock out (C6-KO) mice. Behavioral examinations of 5xFAD/C6-KO double transgenic mice showed improved performance in spatial learning, memory, and anxiety/risk assessment behavior, as compared to 5xFAD mice. Hippocampal mRNA expression analyses showed significantly reduced levels of inflammatory mediator TNF-α, while the anti-inflammatory cytokine IL-10 was increased in 5xFAD/C6-KO mice. A significant reduction in amyloid-β plaques could be observed and immunohistochemistry analyses showed reduced levels of activated microglia and astrocytes in 5xFAD/C6-KO, compared to 5xFAD mice. Together, these results indicate a substantial role for caspase-6 in the pathology of the 5xFAD model of AD and suggest further validation of caspase-6 as a potential therapeutic target for AD.
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Gourmaud S, Thomas P, Thomasseau S, Tible M, Abadie C, Paquet C, Hugon J. Brimapitide Reduced Neuronal Stress Markers and Cognitive Deficits in 5XFAD Transgenic Mice. J Alzheimers Dis 2019; 63:665-674. [PMID: 29660941 DOI: 10.3233/jad-171099] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Alzheimer's disease (AD) is characterized by accumulations of amyloid-β (Aβ42) and hyperphosphorylated tau proteins, associated with neuroinflammation, synaptic loss, and neuronal death. Several studies indicate that c-Jun N-terminal kinase (JNK) is implicated in the pathological features of AD. We have investigated in 5XFAD mice, the therapeutic effects of Brimapitide, a JNK-specific inhibitory peptide previously tested with higher concentrations in another AD model (TgCRND8). Three-month-old 5XFAD and wild-type littermate mice were treated by intravenous injections of low doses (10 mg/kg) of Brimapitide every 3 weeks, for 3 or 6 months (n = 6-9 per group). Cognitive deficits and brain lesions were assessed using Y-maze, fear-conditioning test, and histological and biochemical methods. Chronic treatment of Brimapitide for 3 months resulted in a reduction of Aβ plaque burden in the cortex of 5XFAD treated mice. After 6 months of treatment, cognitive deficits were reduced but also a significant reduction of cell death markers and the pro-inflammatory IL-1β cytokine in treated mice were detected. The Aβ plaque burden was not anymore modified by the 6 months of treatment. In addition to modulating cognition and amyloid plaque accumulation, depending on the treatment duration, Brimapitide seems experimentally to reduce neuronal stress in 5XFAD mice.
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Affiliation(s)
- Sarah Gourmaud
- Inserm UMR-S 942, Paris, France.,Present address: Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | | | | | | | - Claire Paquet
- Inserm UMR-S 942, Paris, France.,Research Memory Centre, Paris Nord Ile de France Saint Louis Lariboisière Fernand Widal Hospital, University Paris Diderot AP-HP, Paris, France
| | - Jacques Hugon
- Inserm UMR-S 942, Paris, France.,Research Memory Centre, Paris Nord Ile de France Saint Louis Lariboisière Fernand Widal Hospital, University Paris Diderot AP-HP, Paris, France
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Bundy JL, Vied C, Badger C, Nowakowski RS. Sex-biased hippocampal pathology in the 5XFAD mouse model of Alzheimer's disease: A multi-omic analysis. J Comp Neurol 2018; 527:462-475. [PMID: 30291623 DOI: 10.1002/cne.24551] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 08/16/2018] [Accepted: 09/25/2018] [Indexed: 01/01/2023]
Abstract
Alzheimer's disease is a progressive neurodegenerative disorder and the most common form of dementia. Like many neurological disorders, Alzheimer's disease has a sex-biased epidemiological profile, affecting approximately twice as many women as men. The cause of this sex difference has yet to be elucidated. To identify molecular correlates of this sex bias, we investigated molecular pathology in females and males using the 5XFamilial Alzheimer's disease mutations (5XFAD) genetic mouse model of Alzheimer's disease. We profiled the transcriptome and proteome of the mouse hippocampus during early stages of disease development (1, 2, and 4 months of age). Our analysis reveals 42 genes that are differentially expressed between disease and wild-type animals at 2 months of age, prior to observable plaque deposition. In 4-month-old animals, we detect 1,316 differentially expressed transcripts between transgenic and control 5XFAD mice, many of which are associated with immune function. Additionally, we find that some of these transcriptional perturbations are correlated with altered protein levels in 4-month-old transgenic animals. Importantly, our data indicate that female 5XFAD mouse exhibit more profound pathology than their male counterparts as measured by differences in gene expression. We also find that the 5XFAD transgenes are more highly expressed in female 5XFAD mice than their male counterparts, which could partially account for the sex-biased molecular pathology observed in this dataset.
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Affiliation(s)
- Joseph L Bundy
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida
| | - Cynthia Vied
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida.,Translational Science Laboratory, Florida State University College of Medicine, Tallahassee, Florida
| | - Crystal Badger
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida
| | - Richard S Nowakowski
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida
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11
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Hui CW, Song X, Ma F, Shen X, Herrup K. Ibuprofen prevents progression of ataxia telangiectasia symptoms in ATM-deficient mice. J Neuroinflammation 2018; 15:308. [PMID: 30400801 PMCID: PMC6220455 DOI: 10.1186/s12974-018-1338-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Accepted: 10/18/2018] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Inflammation plays a critical role in accelerating the progression of neurodegenerative diseases, such as Alzheimer's disease (AD) and ataxia telangiectasia (A-T). In A-T mouse models, LPS-induced neuroinflammation advances the degenerative changes found in cerebellar Purkinje neurons both in vivo and in vitro. In the current study, we ask whether ibuprofen, a non-steroidal anti-inflammatory drug (NSAID), can have the opposite effect and delay the symptoms of the disease. METHODS We tested the beneficial effects of ibuprofen in both in vitro and in vivo models. Conditioned medium from LPS stimulated primary microglia (LM) applied to cultures of dissociated cortical neurons leads to numerous degenerative changes. Pretreatment of the neurons with ibuprofen, however, blocked this damage. Systemic injection of LPS into either adult wild-type or adult Atm-/- mice produced an immune challenge that triggered profound behavioral, biochemical, and histological effects. We used a 2-week ibuprofen pretreatment regimen to investigate whether these LPS effects could be blocked. We also treated young presymptomatic Atm-/- mice to determine if ibuprofen could delay the appearance of symptoms. RESULTS Adding ibuprofen directly to neuronal cultures significantly reduced LM-induced degeneration. Curiously, adding ibuprofen to the microglia cultures before the LPS challenge had little effect, thus implying a direct effect of the NSAID on the neuronal cultures. In vivo administration of ibuprofen to Atm-/- animals before a systemic LPS immune challenge suppressed cytological damage. The ibuprofen effects were widespread as microglial activation, p38 phosphorylation, DNA damage, and neuronal cell cycle reentry were all reduced. Unfortunately, ibuprofen only slightly improved the LPS-induced behavioral deficits. Yet, while the behavioral symptoms could not be reversed once they were established in adult Atm-/- animals, administration of ibuprofen to young mutant pups prevented their symptoms from appearing. CONCLUSION Inflammatory processes impact the normal progression of A-T implying that modulation of the immune system can have therapeutic benefit for both the behavioral and cellular symptoms of this neurodegenerative disease.
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Affiliation(s)
- Chin Wai Hui
- Division of Life Science and State Key Laboratory of Molecular Neurobiology, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Xuan Song
- Division of Life Science and State Key Laboratory of Molecular Neurobiology, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Fulin Ma
- Division of Life Science and State Key Laboratory of Molecular Neurobiology, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Xuting Shen
- Division of Life Science and State Key Laboratory of Molecular Neurobiology, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
- Present address: School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong
| | - Karl Herrup
- Division of Life Science and State Key Laboratory of Molecular Neurobiology, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
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12
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Motor function deficits in the 12 month-old female 5xFAD mouse model of Alzheimer's disease. Behav Brain Res 2017; 337:256-263. [PMID: 28890389 DOI: 10.1016/j.bbr.2017.09.009] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 08/29/2017] [Accepted: 09/04/2017] [Indexed: 11/22/2022]
Abstract
Motor problems occur early in some patients with Alzheimer's disease (AD) and as the disease progresses many patients develop motor dysfunction. Motor dysfunction has been reported in some mouse models of AD, including the 5xFAD mouse, thus this model may be particularly useful for studying motor dysfunction in AD. In order to determine the extent of motor dysfunction in these mice, we tested 11-13 month old female 5xFAD and wildtype (WT) control mice in a battery of motor behaviour tasks. The 5xFAD mice showed hind limb clasping, weighed less and had slower righting reflexes than WT mice. In the open field, the 5xFAD mice travelled a shorter distance than the WT mice, spent less time moving and had a slower movement speed. The 5xFAD mice fell faster than the WT mice from the balance beam, wire suspension, grid suspension and rotarod tasks, indicating dysfunctions in balance, grip strength, motor co-ordination and motor learning. The 5xFAD mice had a short, shuffling gait with a shorter stride length than WT mice and had a slower swim speed. The 5xFAD mice also failed to show an acoustic startle response, likely due to motor dysfunction and previously reported hearing impairment. The 5xFAD mice did not show deficits in the ability of peripheral motor nerves to drive muscle output, suggesting that motor impairments are not due to dysfunction in peripheral motor nerves. These results indicate that the aged 5xFAD mice are deficient in numerous motor behaviours, and suggest that these mice may prove to be a good model for studying the mechanisms of motor dysfunction in AD, and motor behaviour might prove useful for assessing the efficacy of AD therapeutics. Motor dysfunction in 5xFAD mice must also be considered in behavioural tests of sensory and cognitive function so that performance is not confounded by impaired locomotor or swimming behaviour.
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Tai LM, Balu D, Avila-Munoz E, Abdullah L, Thomas R, Collins N, Valencia-Olvera AC, LaDu MJ. EFAD transgenic mice as a human APOE relevant preclinical model of Alzheimer's disease. J Lipid Res 2017; 58:1733-1755. [PMID: 28389477 PMCID: PMC5580905 DOI: 10.1194/jlr.r076315] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 04/06/2017] [Indexed: 01/12/2023] Open
Abstract
Identified in 1993, APOE4 is the greatest genetic risk factor for sporadic Alzheimer's disease (AD), increasing risk up to 15-fold compared with APOE3, with APOE2 decreasing AD risk. However, the functional effects of APOE4 on AD pathology remain unclear and, in some cases, controversial. In vivo progress to understand how the human (h)-APOE genotypes affect AD pathology has been limited by the lack of a tractable familial AD-transgenic (FAD-Tg) mouse model expressing h-APOE rather than mouse (m)-APOE. The disparity between m- and h-apoE is relevant for virtually every AD-relevant pathway, including amyloid-β (Aβ) deposition and clearance, neuroinflammation, tau pathology, neural plasticity and cerebrovascular deficits. EFAD mice were designed as a temporally useful preclinical FAD-Tg-mouse model expressing the h-APOE genotypes for identifying mechanisms underlying APOE-modulated symptoms of AD pathology. From their first description in 2012, EFAD mice have enabled critical basic and therapeutic research. Here we review insights gleaned from the EFAD mice and summarize future directions.
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Affiliation(s)
- Leon M Tai
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612
| | - Deebika Balu
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612
| | - Evangelina Avila-Munoz
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612
| | | | - Riya Thomas
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612
| | - Nicole Collins
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612
| | | | - Mary Jo LaDu
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612.
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Hullmann M, Albrecht C, van Berlo D, Gerlofs-Nijland ME, Wahle T, Boots AW, Krutmann J, Cassee FR, Bayer TA, Schins RPF. Diesel engine exhaust accelerates plaque formation in a mouse model of Alzheimer's disease. Part Fibre Toxicol 2017; 14:35. [PMID: 28854940 PMCID: PMC5577845 DOI: 10.1186/s12989-017-0213-5] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 08/16/2017] [Indexed: 11/24/2022] Open
Abstract
Background Increasing evidence from toxicological and epidemiological studies indicates that the central nervous system is an important target for ambient air pollutants. We have investigated whether long-term inhalation exposure to diesel engine exhaust (DEE), a dominant contributor to particulate air pollution in urban environments, can aggravate Alzheimer’s Disease (AD)-like effects in female 5X Familial AD (5XFAD) mice and their wild-type female littermates. Following 3 and 13 weeks exposures to diluted DEE (0.95 mg/m3, 6 h/day, 5 days/week) or clean air (controls) behaviour tests were performed and amyloid-β (Aβ) plaque formation, pulmonary histopathology and systemic inflammation were evaluated. Results In a string suspension task, assessing for grip strength and motor coordination, 13 weeks exposed 5XFAD mice performed significantly less than the 5XFAD controls. Spatial working memory deficits, assessed by Y-maze and X-maze tasks, were not observed in association with the DEE exposures. Brains of the 3 weeks DEE-exposed 5XFAD mice showed significantly higher cortical Aβ plaque load and higher whole brain homogenate Aβ42 levels than the clean air-exposed 5XFAD littermate controls. After the 13 weeks exposures, with increasing age and progression of the AD-phenotype of the 5XFAD mice, DEE-related differences in amyloid pathology were no longer present. Immunohistochemical evaluation of lungs of the mice revealed no obvious genetic background-related differences in tissue structure, and the DEE exposure did not cause histopathological changes in the mice of both backgrounds. Luminex analysis of plasma cytokines demonstrated absence of sustained systemic inflammation upon DEE exposure. Conclusions Inhalation exposure to DEE causes accelerated plaque formation and motor function impairment in 5XFAD transgenic mice. Our study provides further support that the brain is a relevant target for the effects of inhaled DEE and suggests that long-term exposure to this ubiquitous air pollution mixture may promote the development of Alzheimer’s disease.
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Affiliation(s)
- Maja Hullmann
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Düsseldorf, Germany
| | - Catrin Albrecht
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Düsseldorf, Germany
| | - Damiën van Berlo
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Düsseldorf, Germany.,, Present address: Triskelion BV Utrechtseweg 48, 3704 HE, Zeist, The Netherlands
| | | | - Tina Wahle
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Düsseldorf, Germany
| | - Agnes W Boots
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Düsseldorf, Germany.,Department of Pharmacology and Toxicology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Jean Krutmann
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Düsseldorf, Germany.,Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Flemming R Cassee
- National Institute for Public Health and the Environment, Bilthoven, The Netherlands.,Institute of Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
| | - Thomas A Bayer
- Department of Psychiatry and Psychotherapy, Division of Molecular Psychiatry, Georg-August-University Göttingen, University Medicine Göttingen, Göttingen, Germany
| | - Roel P F Schins
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Düsseldorf, Germany.
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Hüttenrauch M, Walter S, Kaufmann M, Weggen S, Wirths O. Limited Effects of Prolonged Environmental Enrichment on the Pathology of 5XFAD Mice. Mol Neurobiol 2016; 54:6542-6555. [DOI: 10.1007/s12035-016-0167-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 09/27/2016] [Indexed: 10/20/2022]
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16
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Woodling NS, Andreasson KI. Untangling the Web: Toxic and Protective Effects of Neuroinflammation and PGE2 Signaling in Alzheimer's Disease. ACS Chem Neurosci 2016; 7:454-63. [PMID: 26979823 DOI: 10.1021/acschemneuro.6b00016] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The neuroinflammatory response has received increasing attention as a key factor in the pathogenesis of Alzheimer's disease (AD). Microglia, the innate immune cells and resident phagocytes of the brain, respond to accumulating Aβ peptides by generating a nonresolving inflammatory response. While this response can clear Aβ peptides from the nervous system in some settings, its failure to do so in AD accelerates synaptic injury, neuronal loss, and cognitive decline. The complex molecular components of this response are beginning to be unraveled, with identification of both damaging and protective roles for individual components of the neuroinflammatory response. Even within one molecular pathway, contrasting effects are often present. As one example, recent studies of the inflammatory cyclooxygenase-prostaglandin pathway have revealed both beneficial and detrimental effects dependent on the disease context, cell type, and downstream signaling pathway. Nonsteroidal anti-inflammatory drugs (NSAIDs), which inhibit cyclooxygenases, are associated with reduced AD risk when taken by cognitively normal populations, but additional clinical and mouse model studies have added complexities and caveats to this finding. Downstream of cyclooxygenase activity, prostaglandin E2 signaling exerts both damaging pro-inflammatory and protective anti-inflammatory effects through actions of specific E-prostanoid G-protein coupled receptors on specific cell types. These complexities underscore the need for careful study of individual components of the neuroinflammatory response to better understand their contribution to AD pathogenesis and progression.
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Affiliation(s)
- Nathaniel S. Woodling
- Department of Neurology and
Neurological Sciences, Stanford University School of Medicine, 1201
Welch Road, Stanford, California 94305, United States
| | - Katrin I. Andreasson
- Department of Neurology and
Neurological Sciences, Stanford University School of Medicine, 1201
Welch Road, Stanford, California 94305, United States
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Fortin JS, Benoit-Biancamano MO. Inhibition of islet amyloid polypeptide aggregation and associated cytotoxicity by nonsteroidal anti-inflammatory drugs. Can J Physiol Pharmacol 2016; 94:35-48. [DOI: 10.1139/cjpp-2015-0117] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Nonsteroidal anti-inflammatory drugs (NSAIDs) constitute an important pharmacotherapeutic class that, over the past decade, have expanded in application to a panoply of medical conditions. They have been tested for neurodegenerative diseases such as Alzheimer’s to reduce inflammation and also in the attempt to abrogate amyloid deposition. However, the use of NSAIDs as aggregation inhibitors has not been extensively studied in pancreatic amyloid deposition. Pancreatic amyloidosis involves the misfolding of islet amyloid polypeptide (IAPP) and contributes to the progression of type-2 diabetes in humans and felines. To ascertain their antiamyloidogenic activity, several NSAIDs were tested using fluorometric thioflavin-T assays, circular dichroism, photo-induced cross-linking assays, and cell culture. Celecoxib, diclofenac, indomethacin, meloxicam, niflumic acid, nimesulide, phenylbutazone, piroxicam, sulindac, and tenoxicam reduced fibrillization at a molar ratio of 1:10. The circular dichroism spectra of diclofenac, piroxicam, and sulindac showed characteristic spectral signatures found in predominantly α-helical structures. The oligomerization of human IAPP was abrogated with diclofenac and sulindac at a molar ratio of 1:5. The cytotoxic effects of pre-incubated human IAPP on cultured INS-1 cells were noticeably reduced in the presence of diclofenac, meloxicam, phenylbutazone, sulindac, and tenoxicam at a molar ratio of 1:10. Our results demonstrate that NSAIDs can provide chemical scaffolds to generate new and promising antiamyloidogenic agents that can be used alone or as a coadjuvant therapy.
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Affiliation(s)
- Jessica S. Fortin
- Département de Pathologie et de Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, 3200 Sicotte, Saint-Hyacinthe, QC J2S 2M2, Canada
- Département de Pathologie et de Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, 3200 Sicotte, Saint-Hyacinthe, QC J2S 2M2, Canada
| | - Marie-Odile Benoit-Biancamano
- Département de Pathologie et de Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, 3200 Sicotte, Saint-Hyacinthe, QC J2S 2M2, Canada
- Département de Pathologie et de Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, 3200 Sicotte, Saint-Hyacinthe, QC J2S 2M2, Canada
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18
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Herbst-Robinson KJ, Liu L, James M, Yao Y, Xie SX, Brunden KR. Inflammatory Eicosanoids Increase Amyloid Precursor Protein Expression via Activation of Multiple Neuronal Receptors. Sci Rep 2015; 5:18286. [PMID: 26672557 PMCID: PMC4682150 DOI: 10.1038/srep18286] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 10/26/2015] [Indexed: 01/27/2023] Open
Abstract
Senile plaques comprised of Aβ peptides are a hallmark of Alzheimer's disease (AD) brain, as are activated glia that release inflammatory molecules, including eicosanoids. Previous studies have demonstrated that amyloid precursor protein (APP) and Aβ levels can be increased through activation of thromboxane A2-prostanoid (TP) receptors on neurons. We demonstrate that TP receptor regulation of APP expression depends on Gαq-signaling and conventional protein kinase C isoforms. Importantly, we discovered that Gαq-linked prostaglandin E2 and leukotriene D4 receptors also regulate APP expression. Prostaglandin E2 and thromboxane A2, as well as total APP levels, were found to be elevated in the brains of aged 5XFAD transgenic mice harboring Aβ plaques and activated glia, suggesting that increased APP expression resulted from eicosanoid binding to Gαq-linked neuronal receptors. Notably, inhibition of eicosanoid synthesis significantly lowered brain APP protein levels in aged 5XFAD mice. These results provide new insights into potential AD therapeutic strategies.
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Affiliation(s)
- Katie J. Herbst-Robinson
- Department of Pathology and Laboratory Medicine, Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Li Liu
- Department of Pathology and Laboratory Medicine, Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Michael James
- Department of Pathology and Laboratory Medicine, Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Yuemang Yao
- Department of Pathology and Laboratory Medicine, Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Sharon X. Xie
- Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Kurt R. Brunden
- Department of Pathology and Laboratory Medicine, Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
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Franco R, Petrovic M. Suggesting a Way to Understand the Actual Potential of Anti-Alzheimer's Disease Drugs That Show Promise in Transgenic Mouse Models. Front Neurol 2015; 6:206. [PMID: 26500603 PMCID: PMC4594007 DOI: 10.3389/fneur.2015.00206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 09/08/2015] [Indexed: 11/30/2022] Open
Affiliation(s)
- Rafael Franco
- Departament de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Barcelona , Barcelona , Spain ; Centro de Investigación Biomédica en Red: Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III , Madrid , Spain
| | - Milos Petrovic
- School of Pharmacy and Biomedical Sciences, University of Central Lancashire , Preston , UK
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20
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Ling IF, Golde TE, Galasko DR, Koo EH. Modulation of Aβ42 in vivo by γ-secretase modulator in primates and humans. ALZHEIMERS RESEARCH & THERAPY 2015; 7:55. [PMID: 26244059 PMCID: PMC4523931 DOI: 10.1186/s13195-015-0137-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 07/02/2015] [Indexed: 01/10/2023]
Abstract
Introduction Ibuprofen is one of the nonsteroidal anti-inflammatory drugs that have been shown to selectively lower pathogenic amyloid beta-peptide (Aβ)42 without impairing overall γ-secretase activity in vitro. This γ-secretase modulator (GSM) activity has been hypothesized to contribute to the reduction in risk of developing Alzheimer’s disease in chronic users of nonsteroidal anti-inflammatory drugs. However, it is unclear whether ibuprofen, within therapeutic dosing range, demonstrates GSM activity in humans. In this study, we evaluated the effects of ibuprofen and a second-generation GSM, GSM-1, on Aβ levels in cerebrospinal fluid and plasma of young nonhuman primates and humans. Methods Five to seven conscious cynomolgus monkeys (Macaca fascicularis) were nontreated or treated with 30 mg/kg GSM-1 or 50 or 100 mg/kg ibuprofen and the plasma and cerebrospinal fluid were sampled at −8, 0 (baseline or right before treatment), 2, 4, 6, 8, 12, and 24 h postdosing. In addition, sixteen healthy human subjects were randomly assigned to receive either placebo or 800 mg ibuprofen given by intravenous administration and plasma were collected at 0 (before drug infusion), 0.5, 1, 2, 4, 6, 8, 10, and 24 h after dosing. Results A single dose of GSM-1 (30 mg/kg) decreased the ratio of Aβ42 to Aβ40 to 60 % in plasma and the ratio of Aβ42 to total Aβ to 65 % in cerebrospinal fluid from baseline to postdosing in monkeys. However, no significant changes were detected following ibuprofen treatment at 100 mg/kg. Consistent with the results from nonhuman primates, ibuprofen did not alter plasma Aβ levels in human volunteers after a single 800 mg dose. Conclusions GSM-1 exerted potent lowering of the ratio of Aβ42 to Aβ40 in nonhuman primates but the hypothesized GSM activity of ibuprofen could not be demonstrated in nonhuman primates and humans after acute dosing.
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Affiliation(s)
- I-Fang Ling
- Department of Neurosciences, University of California, La Jolla, San Diego, CA USA
| | - Todd E Golde
- Department of Neuroscience, University of Florida, College of Medicine, Gainesville, FL USA
| | - Douglas R Galasko
- Department of Neurosciences, University of California, La Jolla, San Diego, CA USA
| | - Edward H Koo
- Department of Neurosciences, University of California, La Jolla, San Diego, CA USA ; Departments of Medicine and Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
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Choi JK, Carreras I, Aytan N, Jenkins-Sahlin E, Dedeoglu A, Jenkins BG. The effects of aging, housing and ibuprofen treatment on brain neurochemistry in a triple transgene Alzheimer's disease mouse model using magnetic resonance spectroscopy and imaging. Brain Res 2014; 1590:85-96. [PMID: 25301691 DOI: 10.1016/j.brainres.2014.09.067] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 09/09/2014] [Accepted: 09/27/2014] [Indexed: 01/18/2023]
Abstract
We investigated a triple transgene Alzheimer's disease (AD) mouse model that recapitulates many of the neurochemical, anatomic, pathologic and behavioral defects seen in human AD. We studied the mice as a function of age and brain region and investigated potential therapy with the non-steroidal anti-inflammatory drug ibuprofen. Magnetic resonance spectroscopy (MRS) showed alterations characteristic of AD (i.e. increased myo-inositol and decreased N-acetylaspartate (NAA)). Mice at 6 months of age showed an increase in myo-inositol in the hippocampus at a time when the Aβ is intracellular, but not in amygdala or cortex. Myo-inositol increased as a function of age in the amygdala, cortex and striatum while NAA decreased only in the hippocampus and cortex at 17-23 months of age. Ibuprofen protected the increase of myo-inositol at six months of age in the hippocampus, but had no effect at 17-23 months of age (a time when Aβ is extracellular). In vivo MRI and MRS showed that at 17-23 months of age there was a significant protective effect of ibuprofen on hippocampal volume and NAA loss. Together, these data show the following: the increase in myo-inositol occurs before the decrease in NAA in hippocampus but not cortex; the hippocampus shows earlier changes than does the amygdale or cortex consistent with earlier deposition of Aβ40-42 in the hippocampus and ibuprofen protects against multiple components of the AD pathology. These data also show a profound effect of housing on this particular mouse model.
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Affiliation(s)
- Ji-Kyung Choi
- Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
| | - Isabel Carreras
- Department of Veterans Affairs, VA Boston Healthcare System, Boston, MA 02130, USA; Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
| | - Nur Aytan
- Department of Veterans Affairs, VA Boston Healthcare System, Boston, MA 02130, USA; Neurology and Alzheimer's Disease Center, Boston University School of Medicine, Boston, MA, USA
| | - Eric Jenkins-Sahlin
- Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Alpaslan Dedeoglu
- Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA; Department of Veterans Affairs, VA Boston Healthcare System, Boston, MA 02130, USA; Neurology and Alzheimer's Disease Center, Boston University School of Medicine, Boston, MA, USA
| | - Bruce G Jenkins
- Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
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Peripherally triggered and GSK-3β-driven brain inflammation differentially skew adult hippocampal neurogenesis, behavioral pattern separation and microglial activation in response to ibuprofen. Transl Psychiatry 2014; 4:e463. [PMID: 25313506 PMCID: PMC4350524 DOI: 10.1038/tp.2014.92] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 07/24/2014] [Accepted: 08/13/2014] [Indexed: 12/14/2022] Open
Abstract
Both familial and sporadic forms of Alzheimer disease (AD) present memory impairments. It has been proposed that these impairments are related to inflammation in relevant brain areas such as the hippocampus. Whether peripherally triggered and neuron-driven brain inflammation produce similar and equally reversible alterations is a matter of discussion. Here we studied the effects of ibuprofen administration on a familial AD mouse model overexpressing GSK-3β that presents severe brain inflammation. We compared these effects with those observed in a peripherally triggered brain inflammation model based on chronic lipopolysaccharide (LPS) administration. Both proinflammatory stimuli produced equivalent reversible morphological alterations in granule neurons; however, GSK-3β had a much more prominent role in newborn neuron connectivity, causing alterations that were not reversed by ibuprofen. Although both insults triggered similar behavioral impairments, ibuprofen rescued this defect in LPS-treated mice but did not produce any improvement in GSK-3β-overexpressing animals. This observation could be attributable to the different microglial phenotype induced by ibuprofen treatment. These data may be clinically relevant for AD therapies, as GSK-3β appears to determine the efficacy of ibuprofen treatment.
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Landel V, Baranger K, Virard I, Loriod B, Khrestchatisky M, Rivera S, Benech P, Féron F. Temporal gene profiling of the 5XFAD transgenic mouse model highlights the importance of microglial activation in Alzheimer's disease. Mol Neurodegener 2014; 9:33. [PMID: 25213090 PMCID: PMC4237952 DOI: 10.1186/1750-1326-9-33] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 08/27/2014] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND The 5XFAD early onset mouse model of Alzheimer's disease (AD) is gaining momentum. Behavioral, electrophysiological and anatomical studies have identified age-dependent alterations that can be reminiscent of human AD. However, transcriptional changes during disease progression have not yet been investigated. To this end, we carried out a transcriptomic analysis on RNAs from the neocortex and the hippocampus of 5XFAD female mice at the ages of one, four, six and nine months (M1, M4, M6, M9). RESULTS Our results show a clear shift in gene expression patterns between M1 and M4. At M1, 5XFAD animals exhibit region-specific variations in gene expression patterns whereas M4 to M9 mice share a larger proportion of differentially expressed genes (DEGs) that are common to both regions. Analysis of DEGs from M4 to M9 underlines the predominance of inflammatory and immune processes in this AD mouse model. The rise in inflammation, sustained by the overexpression of genes from the complement and integrin families, is accompanied by an increased expression of transcripts involved in the NADPH oxidase complex, phagocytic processes and IFN-γ related pathways. CONCLUSIONS Overall, our data suggest that, from M4 to M9, sustained microglial activation becomes the predominant feature and point out that both detrimental and neuroprotective mechanisms appear to be at play in this model. Furthermore, our study identifies a number of genes already known to be altered in human AD, thus confirming the use of the 5XFAD strain as a valid model for understanding AD pathogenesis and for screening potential therapeutic molecules.
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Affiliation(s)
- Véréna Landel
- Aix Marseille Université, CNRS, NICN UMR 7259, 13916 Marseille, France
| | - Kévin Baranger
- Aix Marseille Université, CNRS, NICN UMR 7259, 13916 Marseille, France
- APHM, Hôpitaux de la Timone, Service de Neurologie et Neuropsychologie, 13385 Marseille, France
| | - Isabelle Virard
- Aix Marseille Université, CNRS, NICN UMR 7259, 13916 Marseille, France
| | - Béatrice Loriod
- Aix Marseille Université, TAGC UMR 1090, 13288 Marseille, France
- INSERM, TAGC UMR 1090, 13288 Marseille, France
| | | | - Santiago Rivera
- Aix Marseille Université, CNRS, NICN UMR 7259, 13916 Marseille, France
| | - Philippe Benech
- Aix Marseille Université, CNRS, NICN UMR 7259, 13916 Marseille, France
| | - François Féron
- Aix Marseille Université, CNRS, NICN UMR 7259, 13916 Marseille, France
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Christensen DZ, Huettenrauch M, Mitkovski M, Pradier L, Wirths O. Axonal degeneration in an Alzheimer mouse model is PS1 gene dose dependent and linked to intraneuronal Aβ accumulation. Front Aging Neurosci 2014; 6:139. [PMID: 25018730 PMCID: PMC4073286 DOI: 10.3389/fnagi.2014.00139] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 06/11/2014] [Indexed: 11/25/2022] Open
Abstract
Abnormalities and impairments in axonal transport are suggested to strongly contribute to the pathological alterations underlying AD. The exact mechanisms leading to axonopathy are currently unclear, but it was recently suggested that APP expression itself triggers axonal degeneration. We used APP transgenic mice and crossed them on a hemi- or homozygous PS1 knock-in background (APP/PS1KI). Depending on the mutant PS1 dosage, we demonstrate a clear aggravation in both plaque-associated and plaque-distant axonal degeneration, despite of an unchanged APP expression level. Amyloid-β (Aβ) peptides were found to accumulate in axonal swellings as well as in axons and apical dendrites proximate to neurons accumulating intraneuronal Aβ in their cell bodies. This suggests that Aβ can be transported within neurites thereby contributing to axonal deficits. In addition, diffuse extracellular Aβ deposits were observed in the close vicinity of axonal spheroids accumulating intracellular Aβ, which might be indicative of a local Aβ release from sites of axonal damage.
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Affiliation(s)
- Ditte Z Christensen
- Division of Molecular Psychiatry, Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University Goettingen, Germany
| | - Melanie Huettenrauch
- Division of Molecular Psychiatry, Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University Goettingen, Germany
| | - Miso Mitkovski
- Light Microscopy Facility, Max-Planck-Institute of Experimental Medicine Goettingen, Germany
| | - Laurent Pradier
- Central Nervous System Department, Centre de Recherche Vitry-Alfortville, Sanofi-Aventis Vitry-sur-Seine, France
| | - Oliver Wirths
- Division of Molecular Psychiatry, Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University Goettingen, Germany
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Rodriguez GA, Tai LM, LaDu MJ, Rebeck GW. Human APOE4 increases microglia reactivity at Aβ plaques in a mouse model of Aβ deposition. J Neuroinflammation 2014; 11:111. [PMID: 24948358 PMCID: PMC4077554 DOI: 10.1186/1742-2094-11-111] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 05/29/2014] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Having the apolipoprotein E4 (APOE-ϵ4) allele is the strongest genetic risk factor for the development of Alzheimer's disease (AD). Accumulation of amyloid beta (Aβ) in the brain is influenced by APOE genotype. Transgenic mice co-expressing five familial AD mutations (5xFAD) in the presence of human APOE alleles (ϵ2, ϵ3 or ϵ4) exhibit APOE genotype-specific differences in early Aβ accumulation, suggesting an interaction between APOE and AD pathology. Whether APOE genotype affects Aβ-plaque-associated neuroinflammation remains unclear. In the current study, we address the role of APOE genotype on Aβ-associated microglial reactivity in the EFAD transgenic mouse model. METHODS We analyzed Aβ-induced glial activation in the brains of 6-month-old EFAD transgenic mice (E2FAD, E3FAD and E4FAD). Region-specific morphological profiles of Aβ plaques in EFAD brain sections were compared using immunofluorescence staining. We then determined the degree of glial activation in sites of Aβ deposition while comparing levels of the inflammatory cytokine Interleukin-1β (IL-1β) by ELISA. Finally, we quantified parameters of Aβ-associated microglial reactivity using double-stained EFAD brain sections. RESULTS Characterization of Aβ plaques revealed there were larger and more intensely stained plaques in E4FAD mice relative to E2FAD and E3FAD mice. E4FAD mice also had a greater percentage of compact plaques in the subiculum than E3FAD mice. Reactive microglia and dystrophic astrocytes were prominent in EFAD brains, and primarily localized to two sites of significant Aβ deposition: the subiculum and deep layers of the cortex. Cortical levels of IL-1β were nearly twofold greater in E4FAD mice relative to E3FAD mice. To control for differences in levels of Aβ in the different EFAD mice, we analyzed the microglia within domains of specific Aβ deposits. Morphometric analyses revealed increased measures of microglial reactivity in E4FAD mice, including greater dystrophy, increased fluorescence intensity and a higher density of reactive cells surrounding cortical plaques, than in E3FAD mice. CONCLUSIONS In addition to altering morphological profiles of Aβ deposition, APOE genotype influences Aβ-induced glial activation in the adult EFAD cortex. These data support a role for APOE in modulating Aβ-induced neuroinflammatory responses in AD progression, and support the use of EFAD mice as a suitable model for mechanistic studies of Aβ-associated neuroinflammation.
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Affiliation(s)
- Gustavo A Rodriguez
- Department of Neuroscience, Georgetown University Medical Center, 3970 Reservoir Road, NW Washington, DC 20057, USA
| | - Leon M Tai
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - Mary Jo LaDu
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - G William Rebeck
- Department of Neuroscience, Georgetown University Medical Center, 3970 Reservoir Road, NW Washington, DC 20057, USA
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Bouter Y, Kacprowski T, Weissmann R, Dietrich K, Borgers H, Brauß A, Sperling C, Wirths O, Albrecht M, Jensen LR, Kuss AW, Bayer TA. Deciphering the molecular profile of plaques, memory decline and neuron loss in two mouse models for Alzheimer's disease by deep sequencing. Front Aging Neurosci 2014; 6:75. [PMID: 24795628 PMCID: PMC3997018 DOI: 10.3389/fnagi.2014.00075] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 04/02/2014] [Indexed: 12/23/2022] Open
Abstract
One of the central research questions on the etiology of Alzheimer’s disease (AD) is the elucidation of the molecular signatures triggered by the amyloid cascade of pathological events. Next-generation sequencing allows the identification of genes involved in disease processes in an unbiased manner. We have combined this technique with the analysis of two AD mouse models: (1) The 5XFAD model develops early plaque formation, intraneuronal Aβ aggregation, neuron loss, and behavioral deficits. (2) The Tg4–42 model expresses N-truncated Aβ4–42 and develops neuron loss and behavioral deficits albeit without plaque formation. Our results show that learning and memory deficits in the Morris water maze and fear conditioning tasks in Tg4–42 mice at 12 months of age are similar to the deficits in 5XFAD animals. This suggested that comparative gene expression analysis between the models would allow the dissection of plaque-related and -unrelated disease relevant factors. Using deep sequencing differentially expressed genes (DEGs) were identified and subsequently verified by quantitative PCR. Nineteen DEGs were identified in pre-symptomatic young 5XFAD mice, and none in young Tg4–42 mice. In the aged cohort, 131 DEGs were found in 5XFAD and 56 DEGs in Tg4–42 mice. Many of the DEGs specific to the 5XFAD model belong to neuroinflammatory processes typically associated with plaques. Interestingly, 36 DEGs were identified in both mouse models indicating common disease pathways associated with behavioral deficits and neuron loss.
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Affiliation(s)
- Yvonne Bouter
- Division of Molecular Psychiatry, Georg-August-University Goettingen, University Medicine Goettingen , Goettingen , Germany
| | - Tim Kacprowski
- Department of Bioinformatics, Institute of Biometrics and Medical Informatics, University Medicine Greifswald , Greifswald , Germany ; Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald , Greifswald , Germany
| | - Robert Weissmann
- Human Molecular Genetics, Department for Human Genetics of the Institute for Genetics and Functional Genomics, Institute for Human Genetics, University Medicine Greifswald, Ernst-Moritz-Arndt University Greifswald , Greifswald , Germany
| | - Katharina Dietrich
- Division of Molecular Psychiatry, Georg-August-University Goettingen, University Medicine Goettingen , Goettingen , Germany
| | - Henning Borgers
- Division of Molecular Psychiatry, Georg-August-University Goettingen, University Medicine Goettingen , Goettingen , Germany
| | - Andreas Brauß
- Division of Molecular Psychiatry, Georg-August-University Goettingen, University Medicine Goettingen , Goettingen , Germany
| | - Christian Sperling
- Human Molecular Genetics, Department for Human Genetics of the Institute for Genetics and Functional Genomics, Institute for Human Genetics, University Medicine Greifswald, Ernst-Moritz-Arndt University Greifswald , Greifswald , Germany
| | - Oliver Wirths
- Division of Molecular Psychiatry, Georg-August-University Goettingen, University Medicine Goettingen , Goettingen , Germany
| | - Mario Albrecht
- Department of Bioinformatics, Institute of Biometrics and Medical Informatics, University Medicine Greifswald , Greifswald , Germany ; Institute for Knowledge Discovery, Graz University of Technology , Graz , Austria
| | - Lars R Jensen
- Human Molecular Genetics, Department for Human Genetics of the Institute for Genetics and Functional Genomics, Institute for Human Genetics, University Medicine Greifswald, Ernst-Moritz-Arndt University Greifswald , Greifswald , Germany
| | - Andreas W Kuss
- Human Molecular Genetics, Department for Human Genetics of the Institute for Genetics and Functional Genomics, Institute for Human Genetics, University Medicine Greifswald, Ernst-Moritz-Arndt University Greifswald , Greifswald , Germany
| | - Thomas A Bayer
- Division of Molecular Psychiatry, Georg-August-University Goettingen, University Medicine Goettingen , Goettingen , Germany
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Combination therapy in a transgenic model of Alzheimer's disease. Exp Neurol 2013; 250:228-238. [PMID: 24120437 DOI: 10.1016/j.expneurol.2013.10.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 09/16/2013] [Accepted: 10/02/2013] [Indexed: 12/31/2022]
Abstract
The pathological accumulation of the β-amyloid protein (Aβ) has been closely associated with synaptic loss and neurotoxicity contributing to cognitive dysfunction in Alzheimer's disease (AD). Oligomers of Aβ42 appear to be the most neurotoxic form. Two of the most promising attempts to reduce Aβ accumulation have been with scyllo-inositol, an inositol steroisomer, that stabilizes Aβ42 peptide and prevents it from progressing to oligomers and fibrils and R-flurbiprofen, a purified enantiomer of the classical racemic non-steroidal anti-inflammatory drugs (NSAID), flurbiprofen, that retains the ability to specifically lower Aβ42. In the present study we evaluated the effects of scyllo-inositol and the combination treatment of scyllo-inositol+R-flurbiprofen on amyloid pathology and hippocampal-dependent memory function in 5XFAD mice, a model of Aβ pathology characterized by an enormous production of Aβ42. Our expectations were that the combination treatment of scyllo-inositol+R-flurbiprofen would have an additive effect in preventing Aβ accumulation and that cognition would be improved. Mice treated with scyllo-inositol exhibit 41 and 35% reduction in the deposition of the amyloid plaques stained by antibody against Aβ42 and Aβ40 respectively. Scyllo-inositol was not more effective when combined with R-flurbiprofen for the measures tested. Scyllo-inositol treated mice performed significantly better at the radial arm water maze (RAWM) task than untreated and scyllo-inositol+R-flurbiprofen treated mice.
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28
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McGeer PL, McGeer EG. The amyloid cascade-inflammatory hypothesis of Alzheimer disease: implications for therapy. Acta Neuropathol 2013; 126:479-97. [PMID: 24052108 DOI: 10.1007/s00401-013-1177-7] [Citation(s) in RCA: 296] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 09/03/2013] [Accepted: 09/05/2013] [Indexed: 12/14/2022]
Abstract
The amyloid cascade hypothesis is widely accepted as the centerpiece of Alzheimer disease (AD) pathogenesis. It proposes that abnormal production of beta amyloid protein (Abeta) is the cause of AD and that the neurotoxicity is due to Abeta itself or its oligomeric forms. We suggest that this, in itself, cannot be the cause of AD because demonstrating such toxicity requires micromolar concentrations of these Abeta forms, while their levels in brain are a million times lower in the picomolar range. AD probably results from the inflammatory response induced by extracellular Abeta deposits, which later become enhanced by aggregates of tau. The inflammatory response, which is driven by activated microglia, increases over time as the disease progresses. Disease-modifying therapeutic attempts to date have failed and may continue to do so as long as the central role of inflammation is not taken into account. Multiple epidemiological and animal model studies show that NSAIDs, the most widely used antiinflammatory agents, have a substantial sparing effect on AD. These studies provide a proof of concept regarding the anti-inflammatory approach to disease modification. Biomarker studies have indicated that early intervention may be necessary. They have established that disease onset occurs more than a decade before it becomes clinically evident. By combining biomarker and pathological data, it is possible to define six phases of disease development, each separated by about 5 years. Phase one can be identified by decreases in Abeta in the CSF, phase 2 by increases of tau in the CSF plus clear evidence of Abeta brain deposits by PET scanning, phase 3 by slight decreases in brain metabolic rate by PET-FDG scanning, phase 4 by slight decreases in brain volume by MRI scanning plus minimal cognitive impairment, phase 5 by increased scanning abnormalities plus clinical diagnosis of AD, and phase 6 by advanced AD requiring institutional care. Utilization of antiinflammatory agents early in the disease process remains an overlooked therapeutic opportunity. Such agents, while not preventative, have the advantage of being able to inhibit the consequences of both Abeta and tau aggregation. Since there is more than a decade between disease onset and cognitive decline, a window of opportunity exists to introduce truly effective disease-modifying regimens. Taking advantage of this opportunity is the challenge for the future.
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Affiliation(s)
- Patrick L McGeer
- Kinsmen Laboratory of Neurological Research, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC, V6T1Z3, Canada,
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Meraz-Ríos MA, Toral-Rios D, Franco-Bocanegra D, Villeda-Hernández J, Campos-Peña V. Inflammatory process in Alzheimer's Disease. Front Integr Neurosci 2013; 7:59. [PMID: 23964211 PMCID: PMC3741576 DOI: 10.3389/fnint.2013.00059] [Citation(s) in RCA: 251] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Accepted: 07/25/2013] [Indexed: 12/26/2022] Open
Abstract
Alzheimer Disease (AD) is a neurodegenerative disorder and the most common form of dementia. Histopathologically is characterized by the presence of two major hallmarks, the intracellular neurofibrillary tangles (NFTs) and extracellular neuritic plaques (NPs) surrounded by activated astrocytes and microglia. NFTs consist of paired helical filaments of truncated tau protein that is abnormally hyperphosphorylated. The main component in the NP is the amyloid-β peptide (Aβ), a small fragment of 40–42 amino acids with a molecular weight of 4 kD. It has been proposed that the amyloid aggregates and microglia activation are able to favor the neurodegenerative process observed in AD patients. However, the role of inflammation in AD is controversial, because in early stages the inflammation could have a beneficial role in the pathology, since it has been thought that the microglia and astrocytes activated could be involved in Aβ clearance. Nevertheless the chronic activation of the microglia has been related with an increase of Aβ and possibly with tau phosphorylation. Studies in AD brains have shown an upregulation of complement molecules, pro-inflammatory cytokines, acute phase reactants and other inflammatory mediators that could contribute with the neurodegenerative process. Clinical trials and animal models with non-steroidal anti-inflammatory drugs (NSAIDs) indicate that these drugs may decrease the risk of developing AD and apparently reduce Aβ deposition. Finally, further studies are needed to determine whether treatment with anti-inflammatory strategies, may decrease the neurodegenerative process that affects these patients.
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Affiliation(s)
- Marco A Meraz-Ríos
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados Mexico City, Mexico
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