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Wang J, Huffman D, Ajwad A, McLouth CJ, Bachstetter A, Kohler K, Murphy MP, O'Hara BF, Duncan MJ, Sunderam S. Thermoneutral temperature exposure enhances slow-wave sleep with a correlated improvement in amyloid pathology in a triple-transgenic mouse model of Alzheimer's disease. Sleep 2024; 47:zsae078. [PMID: 38512801 DOI: 10.1093/sleep/zsae078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 01/14/2024] [Indexed: 03/23/2024] Open
Abstract
Accumulation of amyloid-β (Aβ) plays an important role in Alzheimer's disease (AD) pathology. There is growing evidence that disordered sleep may accelerate AD pathology by impeding the physiological clearance of Aβ from the brain that occurs in normal sleep. Therapeutic strategies for improving sleep quality may therefore help slow disease progression. It is well documented that the composition and dynamics of sleep are sensitive to ambient temperature. We therefore compared Aβ pathology and sleep metrics derived from polysomnography in 12-month-old female 3xTg-AD mice (n = 8) exposed to thermoneutral temperatures during the light period over 4 weeks to those of age- and sex-matched controls (n = 8) that remained at normal housing temperature (22°C) during the same period. The treated group experienced greater proportions of slow wave sleep (SWS)-i.e. epochs of elevated 0.5-2 Hz EEG slow wave activity during non-rapid eye movement (NREM) sleep-compared to controls. Assays performed on mouse brain tissue harvested at the end of the experiment showed that exposure to thermoneutral temperatures significantly reduced levels of DEA-soluble (but not RIPA- or formic acid-soluble) Aβ40 and Aβ42 in the hippocampus, though not in the cortex. With both groups pooled together and without regard to treatment condition, NREM sleep continuity and any measure of SWS within NREM at the end of the treatment period were inversely correlated with DEA-soluble Aβ40 and Aβ42 levels, again in the hippocampus but not in the cortex. These findings suggest that experimental manipulation of SWS could offer useful clues into the mechanisms and treatment of AD.
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Affiliation(s)
- Jun Wang
- F. Joseph Halcomb III, MD, Department of Biomedical Engineering, University of Kentucky, Lexington, KY, USA
| | - Dillon Huffman
- F. Joseph Halcomb III, MD, Department of Biomedical Engineering, University of Kentucky, Lexington, KY, USA
| | - Asma'a Ajwad
- F. Joseph Halcomb III, MD, Department of Biomedical Engineering, University of Kentucky, Lexington, KY, USA
- Department of Physiology, University of Diyala College of Medicine, Diyala, Iraq
| | | | - Adam Bachstetter
- Department of Neuroscience, University of Kentucky, Lexington, KY, USA
| | - Katarina Kohler
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
| | - M Paul Murphy
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
| | - Bruce F O'Hara
- Department of Biology, University of Kentucky, Lexington, KY, USA
| | - Marilyn J Duncan
- Department of Neuroscience, University of Kentucky, Lexington, KY, USA
| | - Sridhar Sunderam
- F. Joseph Halcomb III, MD, Department of Biomedical Engineering, University of Kentucky, Lexington, KY, USA
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2
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Wang S, Xiao Y, An X, Luo L, Gong K, Yu D. A comprehensive review of the literature on CD10: its function, clinical application, and prospects. Front Pharmacol 2024; 15:1336310. [PMID: 38389922 PMCID: PMC10881666 DOI: 10.3389/fphar.2024.1336310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 01/29/2024] [Indexed: 02/24/2024] Open
Abstract
CD10, a zinc-dependent metalloprotease found on the cell surface, plays a pivotal role in an array of physiological and pathological processes including cardiovascular regulation, immune function, fetal development, pain response, oncogenesis, and aging. Recognized as a biomarker for hematopoietic and tissue stem cells, CD10 has garnered attention for its prognostic potential in the progression of leukemia and various solid tumors. Recent studies underscore its regulatory significance and therapeutic promise in combating Alzheimer's disease (AD), and it is noted for its protective role in preventing heart failure (HF), obesity, and type-2 diabetes. Furthermore, CD10/substance P interaction has also been shown to contribute to the pain signaling regulation and immunomodulation in diseases such as complex regional pain syndrome (CRPS) and osteoarthritis (OA). The emergence of COVID-19 has sparked interest in CD10's involvement in the disease's pathogenesis. Given its association with multiple disease states, CD10 is a prime therapeutic target; inhibitors targeting CD10 are now being advanced as therapeutic agents. This review compiles recent and earlier literature on CD10, elucidating its physicochemical attributes, tissue-specific expression, and molecular functions. Furthermore, it details the association of CD10 with various diseases and the clinical advancements of its inhibitors, providing a comprehensive overview of its growing significance in medical research.
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Affiliation(s)
- Shudong Wang
- Department of Cardiology, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Yinghui Xiao
- Public Research Platform, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Xingna An
- Public Research Platform, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Ling Luo
- Public Research Platform, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Kejian Gong
- Department of Thoracic Surgery, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Dehai Yu
- Public Research Platform, The First Hospital of Jilin University, Changchun, Jilin, China
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3
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Murphy MP, Buzinova VA, Johnson CE. The amyloid-β peptide: Guilty as charged? Biochim Biophys Acta Mol Basis Dis 2024; 1870:166945. [PMID: 37935338 PMCID: PMC10842071 DOI: 10.1016/j.bbadis.2023.166945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 10/25/2023] [Accepted: 10/31/2023] [Indexed: 11/09/2023]
Abstract
Recent years have seen both considerable progress and controversy in the Alzheimer's disease (AD) field. After decades of slow to negligible movement towards the development of disease modifying therapies, promising outcomes in recent clinical trials with several monoclonal antibodies targeting various forms of the amyloid-β (Aβ) peptide have at last opened a possible way forward. In fact, at this point multiple anti-Aβ therapeutics are close to receiving (or have already received) regulatory approval. Although these outcomes are not without some degree of divisiveness, the fact remains that targeting amyloid for removal has finally shown at least modest efficacy in slowing the otherwise relentless progression of the disease. Although the validation of the long standing amyloid cascade hypothesis would seem to be at hand, what remains is the puzzling issue of why - if Aβ indeed causes AD - does removing it from the brain not stop the disease entirely.
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Affiliation(s)
- M Paul Murphy
- Department of Molecular and Cellular Biochemistry and the Sanders-Brown Center on Aging University of Kentucky, 789 S. Limestone Street, Lexington, KY 40536, USA.
| | - Valeria A Buzinova
- Department of Molecular and Cellular Biochemistry and the Sanders-Brown Center on Aging University of Kentucky, 789 S. Limestone Street, Lexington, KY 40536, USA
| | - Carrie E Johnson
- Department of Molecular and Cellular Biochemistry and the Sanders-Brown Center on Aging University of Kentucky, 789 S. Limestone Street, Lexington, KY 40536, USA
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4
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Kohler K, Macheda T, Hobbs MM, Maisel MT, Rodriguez A, Farris L, Wessel CR, Infantino C, Niedowicz DM, Helman AM, Beckett TL, Unrine JM, Murphy MP. Exposure to Lead in Drinking Water Causes Cognitive Impairment via an Alzheimer's Disease Gene-Dependent Mechanism in Adult Mice. J Alzheimers Dis 2024; 100:S291-S304. [PMID: 39121129 DOI: 10.3233/jad-240640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/11/2024]
Abstract
Background Exposure to lead (Pb) is a major public health problem that could occur through contaminated soil, air, food, or water, either during the course of everyday life, or while working in hazardous occupations. Although Pb has long been known as a neurodevelopmental toxicant in children, a recent and growing body of epidemiological research indicates that cumulative, low-level Pb exposure likely drives age-related neurologic dysfunction in adults. Environmental Pb exposure in adulthood has been linked to risk of late-onset Alzheimer's disease (AD) and dementia. Objective Although the biological mechanism underlying this link is unknown, it has been proposed that Pb exposure may increase the risk of AD via altering the expression of AD-related genes and, possibly, by activating the molecular pathways underlying AD-related pathology. Methods We investigated Pb exposure using a line of genetically modified mice with AD-causing knock-in mutations in the amyloid precursor protein and presenilin 1 (APPΔNL/ΔNL x PS1P264L/P264L) that had been crossed with Leprdb/db mice to impart vulnerability to vascular pathology. Results Our data show that although Pb exposure in adult mice impairs cognitive function, this effect is not related to either an increase in amyloid pathology or to changes in the expression of common AD-related genes. Pb exposure also caused a significant increase in blood pressure, a well known effect of Pb. Interestingly, although the increase in blood pressure was unrelated to genotype, only mice that carried AD-related mutations developed cognitive dysfunction, in spite of showing no significant change in cerebrovascular pathology. Conclusions These results raise the possibility that the increased risk of dementia associated with Pb exposure in adults may be tied to its subsequent interaction with either pre-existing or developing AD-related neuropathology.
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Affiliation(s)
- Katharina Kohler
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Teresa Macheda
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Misty M Hobbs
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - M Tyler Maisel
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Antonela Rodriguez
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Lindsey Farris
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Caitlin R Wessel
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | | | - Dana M Niedowicz
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Alex M Helman
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Tina L Beckett
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Jason M Unrine
- Department of Plant and Soil Sciences, University of Kentucky Martin-Gatton College of Agriculture, Food, and Environment, Lexington, KY, USA
- Kentucky Water Research Institute, University of Kentucky, Lexington, KY, USA
| | - M Paul Murphy
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
- Kentucky Water Research Institute, University of Kentucky, Lexington, KY, USA
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Sharma H, Chang KA, Hulme J, An SSA. Mammalian Models in Alzheimer's Research: An Update. Cells 2023; 12:2459. [PMID: 37887303 PMCID: PMC10605533 DOI: 10.3390/cells12202459] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 10/09/2023] [Accepted: 10/10/2023] [Indexed: 10/28/2023] Open
Abstract
A form of dementia distinct from healthy cognitive aging, Alzheimer's disease (AD) is a complex multi-stage disease that currently afflicts over 50 million people worldwide. Unfortunately, previous therapeutic strategies developed from murine models emulating different aspects of AD pathogenesis were limited. Consequently, researchers are now developing models that express several aspects of pathogenesis that better reflect the clinical situation in humans. As such, this review seeks to provide insight regarding current applications of mammalian models in AD research by addressing recent developments and characterizations of prominent transgenic models and their contributions to pathogenesis as well as discuss the advantages, limitations, and application of emerging models that better capture genetic heterogeneity and mixed pathologies observed in the clinical situation.
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Affiliation(s)
- Himadri Sharma
- Department of Bionano Technology, Gachon Bionano Research Institute, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si 461-701, Gyeonggi-do, Republic of Korea
| | - Keun-A Chang
- Neuroscience Research Institute, Gachon University, Incheon 21565, Republic of Korea
| | - John Hulme
- Department of Bionano Technology, Gachon Bionano Research Institute, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si 461-701, Gyeonggi-do, Republic of Korea
| | - Seong Soo A. An
- Department of Bionano Technology, Gachon Bionano Research Institute, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si 461-701, Gyeonggi-do, Republic of Korea
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Depletion of Paraoxonase 1 (Pon1) Dysregulates mTOR, Autophagy, and Accelerates Amyloid Beta Accumulation in Mice. Cells 2023; 12:cells12050746. [PMID: 36899882 PMCID: PMC10001133 DOI: 10.3390/cells12050746] [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: 01/20/2023] [Revised: 02/16/2023] [Accepted: 02/22/2023] [Indexed: 03/02/2023] Open
Abstract
Paraoxonase 1 (PON1), a homocysteine (Hcy)-thiolactone detoxifying enzyme, has been associated with Alzheimer's disease (AD), suggesting that PON1 plays an important protective role in the brain. To study the involvement of PON1 in the development of AD and to elucidate the mechanism involved, we generated a new mouse model of AD, the Pon1-/-xFAD mouse, and examined how Pon1 depletion affects mTOR signaling, autophagy, and amyloid beta (Aβ) accumulation. To elucidate the mechanism involved, we examined these processes in N2a-APPswe cells. We found that Pon1 depletion significantly downregulated Phf8 and upregulated H4K20me1; mTOR, phospho-mTOR, and App were upregulated while autophagy markers Bcln1, Atg5, and Atg7 were downregulated at the protein and mRNA levels in the brains of Pon1─/─5xFAD vs. Pon1+/+5xFAD mice. Pon1 depletion in N2a-APPswe cells by RNA interference led to downregulation of Phf8 and upregulation of mTOR due to increased H4K20me1-mTOR promoter binding. This led to autophagy downregulation and significantly increased APP and Aβ levels. Phf8 depletion by RNA interference or treatments with Hcy-thiolactone or N-Hcy-protein metabolites similarly increased Aβ levels in N2a-APPswe cells. Taken together, our findings define a neuroprotective mechanism by which Pon1 prevents Aβ generation.
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Witucki Ł, Borowczyk K, Suszyńska-Zajczyk J, Warzych E, Pawlak P, Jakubowski H. Deletion of the Homocysteine Thiolactone Detoxifying Enzyme Bleomycin Hydrolase, in Mice, Causes Memory and Neurological Deficits and Worsens Alzheimer's Disease-Related Behavioral and Biochemical Traits in the 5xFAD Model of Alzheimer's Disease. J Alzheimers Dis 2023; 95:1735-1755. [PMID: 37718819 PMCID: PMC10578231 DOI: 10.3233/jad-230578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/05/2023] [Indexed: 09/19/2023]
Abstract
BACKGROUND Bleomycin hydrolase (BLMH), a homocysteine (Hcy)-thiolactone detoxifying enzyme, is attenuated in Alzheimer's disease (AD) brains. Blmh loss causes astrogliosis in mice while the loss of histone demethylase Phf8, which controls mTOR signaling, causes neuropathy in mice and humans. OBJECTIVE To examine how Blmh gene deletion affects the Phf8/H4K20me1/mTOR/autophagy pathway, amyloid-β (Aβ) accumulation, and cognitive/neuromotor performance in mice. METHODS We generated a new mouse model of AD, the Blmh-/-5xFAD mouse. Behavioral assessments were conducted by cognitive/neuromotor testing. Blmh and Phf8 genes were silenced in mouse neuroblastoma N2a-APPswe cells by RNA interference. mTOR- and autophagy-related proteins, and AβPP were quantified by western blotting and the corresponding mRNAs by RT-qPCR. Aβ was quantified by western blotting (brains) and by confocal microscopy (cells). RESULTS Behavioral testing showed cognitive/neuromotor deficits in Blmh-/- and Blmh-/-5xFAD mice. Phf8 was transcriptionally downregulated in Blmh-/- and Blmh-/-5xFAD brains. H4K20me1, mTOR, phospho-mTOR, and AβPP were upregulated while autophagy markers Becn1, Atg5, and Atg7 were downregulated in Blmh-/- and Blmh-/-5xFAD brains. Aβ was elevated in Blmh-/-5xFAD brains. These biochemical changes were recapitulated in Blmh-silenced N2a-APPswe cells, which also showed increased H4K20me1-mTOR promoter binding and impaired autophagy flux (Lc3-I, Lc3-II, p62). Phf8-silencing or treatments with Hcy-thiolactone or N-Hcy-protein, metabolites elevated in Blmh-/- mice, induced biochemical changes in N2a-APPswe cells like those induced by the Blmh-silencing. However, Phf8-silencing elevated Aβ without affecting AβPP. CONCLUSIONS Our findings show that Blmh interacts with AβPP and the Phf8/H4K20me1/mTOR/autophagy pathway, and that disruption of those interactions causes Aβ accumulation and cognitive/neuromotor deficits.
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Affiliation(s)
- Łukasz Witucki
- Department of Biochemistry and Biotechnology, Poznań University of Life Sciences, Poznań, Poland
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers University, New Jersey Medical School, International Center for Public Health, Newark, NJ, USA
| | - Kamila Borowczyk
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers University, New Jersey Medical School, International Center for Public Health, Newark, NJ, USA
| | - Joanna Suszyńska-Zajczyk
- Department of Biochemistry and Biotechnology, Poznań University of Life Sciences, Poznań, Poland
| | - Ewelina Warzych
- Department of Genetics and Animal Breeding, Poznań University of Life Sciences, Poznań, Poland
| | - Piotr Pawlak
- Department of Genetics and Animal Breeding, Poznań University of Life Sciences, Poznań, Poland
| | - Hieronim Jakubowski
- Department of Biochemistry and Biotechnology, Poznań University of Life Sciences, Poznań, Poland
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers University, New Jersey Medical School, International Center for Public Health, Newark, NJ, USA
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Luo YP, Liu Z, Wang C, Yang XF, Wu XY, Tian XL, Wen HZ. Anodal transcranial direct current stimulation alleviates cognitive impairment in an APP/PS1 model of Alzheimer's disease in the preclinical stage. Neural Regen Res 2022; 17:2278-2285. [PMID: 35259850 PMCID: PMC9083165 DOI: 10.4103/1673-5374.337053] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Anodal transcranial direct current stimulation (AtDCS) has been shown to alleviate cognitive impairment in an APP/PS1 model of Alzheimer's disease in the preclinical stage. However, this enhancement was only observed immediately after AtDCS, and the long-term effect of AtDCS remains unknown. In this study, we treated 26-week-old mouse models of Alzheimer's disease in the preclinical stage with 10 AtDCS sessions or sham stimulation. The Morris water maze, novel object recognition task, and novel object location test were implemented to evaluate spatial learning memory and recognition memory of mice. Western blotting was used to detect the relevant protein content. Morphological changes were observed using immunohistochemistry and immunofluorescence staining. Six weeks after treatment, the mice subjected to AtDCS sessions had a shorter escape latency, a shorter path length, more platform area crossings, and spent more time in the target quadrant than sham-stimulated mice. The mice subjected to AtDCS sessions also performed better in the novel object recognition and novel object location tests than sham-stimulated mice. Furthermore, AtDCS reduced the levels of amyloid-β42 and glial fibrillary acidic protein, a marker of astrocyte activation, and increased the level of neuronal marker NeuN in hippocampal tissue. These findings suggest that AtDCS can improve the spatial learning and memory abilities and pathological state of an APP/PS1 mouse model of Alzheimer's disease in the preclinical stage, with improvements that last for at least 6 weeks.
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Affiliation(s)
- Yin-Pei Luo
- Chongqing Key Laboratory of Neurobiology, Department of Neurobiology, School of Basic Medicine, Army Medical University; Chongqing Medical Electronics Engineering Technology Research Center, Laboratory of Neural Regulation and Rehabilitation Technology, College of Bioengineering, Chongqing University, Chongqing, China
| | - Zhi Liu
- Department of Histology and Embryology, School of Basic Medicine, Army Medical University, Chongqing, China
| | - Cong Wang
- Chongqing Medical Electronics Engineering Technology Research Center, Laboratory of Neural Regulation and Rehabilitation Technology, College of Bioengineering, Chongqing University, Chongqing, China
| | - Xiu-Fang Yang
- Chongqing Medical Electronics Engineering Technology Research Center, Laboratory of Neural Regulation and Rehabilitation Technology, College of Bioengineering, Chongqing University, Chongqing, China
| | - Xiao-Ying Wu
- Chongqing Medical Electronics Engineering Technology Research Center, Laboratory of Neural Regulation and Rehabilitation Technology, College of Bioengineering, Chongqing University, Chongqing, China
| | - Xue-Long Tian
- Chongqing Medical Electronics Engineering Technology Research Center, Laboratory of Neural Regulation and Rehabilitation Technology, College of Bioengineering, Chongqing University, Chongqing, China
| | - Hui-Zhong Wen
- Chongqing Key Laboratory of Neurobiology, Department of Neurobiology, School of Basic Medicine, Army Medical University, Chongqing, China
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Duncan M, Guerriero L, Kohler K, Beechem L, Gillis B, Salisbury F, Wessel C, Wang J, Sunderam S, Bachstetter A, O’Hara B, Murphy M. Chronic Fragmentation of the Daily Sleep-Wake Rhythm Increases Amyloid-beta Levels and Neuroinflammation in the 3xTg-AD Mouse Model of Alzheimer's Disease. Neuroscience 2022; 481:111-122. [PMID: 34856352 PMCID: PMC8941625 DOI: 10.1016/j.neuroscience.2021.11.042] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 11/23/2021] [Accepted: 11/25/2021] [Indexed: 01/17/2023]
Abstract
Fragmentation of the daily sleep-wake rhythm with increased nighttime awakenings and more daytime naps is correlated with the risk of development of Alzheimer's disease (AD). To explore whether a causal relationship underlies this correlation, the present study tested the hypothesis that chronic fragmentation of the daily sleep-wake rhythm stimulates brain amyloid-beta (Aβ) levels and neuroinflammation in the 3xTg-AD mouse model of AD. Female 3xTg-AD mice were allowed to sleep undisturbed or were subjected to chronic sleep fragmentation consisting of four daily sessions of enforced wakefulness (one hour each) evenly distributed during the light phase, five days a week for four weeks. Piezoelectric sleep recording revealed that sleep fragmentation altered the daily sleep-wake rhythm to resemble the pattern observed in AD. Levels of amyloid-beta (Aβ40 and Aβ42) determined by ELISA were higher in hippocampal tissue collected from sleep-fragmented mice than from undisturbed controls. In contrast, hippocampal levels of tau and phospho-tau differed minimally between sleep fragmented and undisturbed control mice. Sleep fragmentation also stimulated neuroinflammation as shown by increased expression of markers of microglial activation and proinflammatory cytokines measured by q-RT-PCR analysis of hippocampal samples. No significant effects of sleep fragmentation on Aβ, tau, or neuroinflammation were observed in the cerebral cortex. These studies support the concept that improving sleep consolidation in individuals at risk for AD may be beneficial for slowing the onset or progression of this devastating neurodegenerative disease.
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Affiliation(s)
- M.J. Duncan
- Dept. of Neuroscience, University of Kentucky College of Medicine, Lexington, KY 40536,Co-senior authors, address correspondence to M.J. Duncan at
| | - L.E. Guerriero
- Dept. of Biology, University of Kentucky, Lexington, KY 40506
| | - K. Kohler
- Dept. of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY 40536,Sanders-Brown Center on Aging and Alzheimer’s Disease Center, University of Kentucky College of Medicine, Lexington, KY 40536
| | - L.E. Beechem
- Dept. of Neuroscience, University of Kentucky College of Medicine, Lexington, KY 40536
| | - B.D. Gillis
- Dept. of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY 40536
| | - F. Salisbury
- Dept. of Biology, University of Kentucky, Lexington, KY 40506
| | - C. Wessel
- Sanders-Brown Center on Aging and Alzheimer’s Disease Center, University of Kentucky College of Medicine, Lexington, KY 40536
| | - J. Wang
- Dept. of Biomedical Engineering, University of Kentucky, Lexington, KY 40506
| | - S. Sunderam
- Dept. of Biomedical Engineering, University of Kentucky, Lexington, KY 40506
| | - A.D. Bachstetter
- Dept. of Neuroscience, University of Kentucky College of Medicine, Lexington, KY 40536,Sanders-Brown Center on Aging and Alzheimer’s Disease Center, University of Kentucky College of Medicine, Lexington, KY 40536,Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536
| | - B.F. O’Hara
- Dept. of Biology, University of Kentucky, Lexington, KY 40506
| | - M.P. Murphy
- Dept. of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY 40536,Sanders-Brown Center on Aging and Alzheimer’s Disease Center, University of Kentucky College of Medicine, Lexington, KY 40536,Co-senior authors, address correspondence to M.J. Duncan at
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10
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Necrostatin-1 Relieves Learning and Memory Deficits in a Zebrafish Model of Alzheimer's Disease Induced by Aluminum. Neurotox Res 2022; 40:198-214. [PMID: 34982355 DOI: 10.1007/s12640-021-00463-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 12/12/2021] [Accepted: 12/14/2021] [Indexed: 12/21/2022]
Abstract
Aluminum (Al) is considered one of the environmental risk factors for Alzheimer's disease (AD). The present study aims to establish a zebrafish AD model induced by Al and explore if necrostation-1 (Nec-1), a specific inhibitor of necroptosis, is effective in relieving learning and memory deficits in the zebrafish AD models. We treated adult zebrafish with aluminum trichloride at various doses for 1 month, followed by a T-maze test to evaluate learning and memory performance. Al concentration, levels of acetylcholine (Ach), and AD-related protein and gene expression in the brain tissue were evaluated in the zebrafish AD models. Our results demonstrated that in the brain tissue of Al-treated zebrafish, Al accumulated, Ach levels decreased, and AD-related genes and proteins increased. As a result, the learning and memory performance of Al-treated zebrafish was impaired. This suggested that a zebrafish AD model was established. To test the effect of Nec-1 on the zebrafish AD model, we added Nec-1 into the culture medium of the Al-treated adult zebrafish. The results demonstrated that Nec-1 could relive the learning and memory deficits, enhance Ach levels and the numbers of neural cells, and impact necroptosis-related gene expression. We concluded that Nec-1 could reverse Al-induced learning and memory impairment and had potential theoretical value in the zebrafish AD model.
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11
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MUTYH Actively Contributes to Microglial Activation and Impaired Neurogenesis in the Pathogenesis of Alzheimer's Disease. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:8635088. [PMID: 34970419 PMCID: PMC8714343 DOI: 10.1155/2021/8635088] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 10/29/2021] [Accepted: 11/19/2021] [Indexed: 12/12/2022]
Abstract
Oxidative stress is a major risk factor for Alzheimer's disease (AD), which is characterized by brain atrophy, amyloid plaques, neurofibrillary tangles, and loss of neurons. 8-Oxoguanine, a major oxidatively generated nucleobase highly accumulated in the AD brain, is known to cause neurodegeneration. In mammalian cells, several enzymes play essential roles in minimizing the 8-oxoguanine accumulation in DNA. MUTYH with adenine DNA glycosylase activity excises adenine inserted opposite 8-oxoguanine in DNA. MUTYH is reported to actively contribute to the neurodegenerative process in Parkinson and Huntington diseases and some mouse models of neurodegenerative diseases by accelerating neuronal dysfunction and microgliosis under oxidative conditions; however, whether or not MUTYH is involved in AD pathogenesis remains unclear. In the present study, we examined the contribution of MUTYH to the AD pathogenesis. Using postmortem human brains, we showed that various types of MUTYH transcripts and proteins are expressed in most hippocampal neurons and glia in both non-AD and AD brains. We further introduced MUTYH deficiency into App NL-G-F/NL-G-F knock-in AD model mice, which produce humanized toxic amyloid-β without the overexpression of APP protein, and investigated the effects of MUTYH deficiency on the behavior, pathology, gene expression, and neurogenesis. MUTYH deficiency improved memory impairment in App NL-G-F/NL-G-F mice, accompanied by reduced microgliosis. Gene expression profiling strongly suggested that MUTYH is involved in the microglial response pathways under AD pathology and contributes to the phagocytic activity of disease-associated microglia. We also found that MUTYH deficiency ameliorates impaired neurogenesis in the hippocampus, thus improving memory impairment. In conclusion, we propose that MUTYH, which is expressed in the hippocampus of AD patients as well as non-AD subjects, actively contributes to memory impairment by inducing microgliosis with poor neurogenesis in the preclinical AD phase and that MUTYH is a novel therapeutic target for AD, as its deficiency is highly beneficial for ameliorating AD pathogenesis.
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Vitek MP, Araujo JA, Fossel M, Greenberg BD, Howell GR, Rizzo SJS, Seyfried NT, Tenner AJ, Territo PR, Windisch M, Bain LJ, Ross A, Carrillo MC, Lamb BT, Edelmayer RM. Translational animal models for Alzheimer's disease: An Alzheimer's Association Business Consortium Think Tank. ALZHEIMER'S & DEMENTIA (NEW YORK, N. Y.) 2021; 6:e12114. [PMID: 33457489 PMCID: PMC7798310 DOI: 10.1002/trc2.12114] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 07/04/2020] [Accepted: 07/09/2020] [Indexed: 12/12/2022]
Abstract
Over 5 million Americans and 50 million individuals worldwide are living with Alzheimer's disease (AD). The progressive dementia associated with AD currently has no cure. Although clinical trials in patients are ultimately required to find safe and effective drugs, animal models of AD permit the integration of brain pathologies with learning and memory deficits that are the first step in developing these new drugs. The purpose of the Alzheimer's Association Business Consortium Think Tank meeting was to address the unmet need to improve the discovery and successful development of Alzheimer's therapies. We hypothesize that positive responses to new therapies observed in validated models of AD will provide predictive evidence for positive responses to these same therapies in AD patients. To achieve this goal, we convened a meeting of experts to explore the current state of AD animal models, identify knowledge gaps, and recommend actions for development of next-generation models with better predictability. Among our findings, we all recognize that models reflecting only single aspects of AD pathogenesis do not mimic AD. Models or combinations of new models are needed that incorporate genetics with environmental interactions, timing of disease development, heterogeneous mechanisms and pathways, comorbidities, and other pathologies that lead to AD and related dementias. Selection of the best models requires us to address the following: (1) which animal species, strains, and genetic backgrounds are most appropriate; (2) which models permit efficient use throughout the drug development pipeline; (3) the translatability of behavioral-cognitive assays from animals to patients; and (4) how to match potential AD therapeutics with particular models. Best practice guidelines to improve reproducibility also need to be developed for consistent use of these models in different research settings. To enhance translational predictability, we discuss a multi-model evaluation strategy to de-risk the successful transition of pre-clinical drug assets to the clinic.
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Affiliation(s)
| | | | | | | | | | | | - Nicholas T. Seyfried
- Departments of Biochemistry and NeurologyEmory School of MedicineAtlantaGeorgiaUSA
| | - Andrea J. Tenner
- Department of Molecular Biology and BiochemistryUniversity of CaliforniaIrvineCaliforniaUSA
| | | | | | - Lisa J. Bain
- Independent Science and Medical WriterElversonPennsylvaniaUSA
| | - April Ross
- Former Alzheimer's Association EmployeeChicagoIllinoisUSA
| | | | - Bruce T. Lamb
- Indiana University School of MedicineStark Neurosciences Research InstituteIndianapolisIndianaUSA
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13
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Quartey MO, Nyarko JNK, Maley JM, Barnes JR, Bolanos MAC, Heistad RM, Knudsen KJ, Pennington PR, Buttigieg J, De Carvalho CE, Leary SC, Parsons MP, Mousseau DD. The Aβ(1-38) peptide is a negative regulator of the Aβ(1-42) peptide implicated in Alzheimer disease progression. Sci Rep 2021; 11:431. [PMID: 33432101 PMCID: PMC7801637 DOI: 10.1038/s41598-020-80164-w] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 12/17/2020] [Indexed: 12/14/2022] Open
Abstract
The pool of β-Amyloid (Aβ) length variants detected in preclinical and clinical Alzheimer disease (AD) samples suggests a diversity of roles for Aβ peptides. We examined how a naturally occurring variant, e.g. Aβ(1-38), interacts with the AD-related variant, Aβ(1-42), and the predominant physiological variant, Aβ(1-40). Atomic force microscopy, Thioflavin T fluorescence, circular dichroism, dynamic light scattering, and surface plasmon resonance reveal that Aβ(1-38) interacts differently with Aβ(1-40) and Aβ(1-42) and, in general, Aβ(1-38) interferes with the conversion of Aβ(1-42) to a β-sheet-rich aggregate. Functionally, Aβ(1-38) reverses the negative impact of Aβ(1-42) on long-term potentiation in acute hippocampal slices and on membrane conductance in primary neurons, and mitigates an Aβ(1-42) phenotype in Caenorhabditis elegans. Aβ(1-38) also reverses any loss of MTT conversion induced by Aβ(1-40) and Aβ(1-42) in HT-22 hippocampal neurons and APOE ε4-positive human fibroblasts, although the combination of Aβ(1-38) and Aβ(1-42) inhibits MTT conversion in APOE ε4-negative fibroblasts. A greater ratio of soluble Aβ(1-42)/Aβ(1-38) [and Aβ(1-42)/Aβ(1-40)] in autopsied brain extracts correlates with an earlier age-at-death in males (but not females) with a diagnosis of AD. These results suggest that Aβ(1-38) is capable of physically counteracting, potentially in a sex-dependent manner, the neuropathological effects of the AD-relevant Aβ(1-42).
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Affiliation(s)
- Maa O Quartey
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, GB41 HSB, 107 Wiggins Rd., Saskatoon, SK, S7N 5E5, Canada
| | - Jennifer N K Nyarko
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, GB41 HSB, 107 Wiggins Rd., Saskatoon, SK, S7N 5E5, Canada
| | - Jason M Maley
- Saskatchewan Structural Sciences Centre, University of Saskatchewan, Saskatoon, SK, Canada
| | - Jocelyn R Barnes
- Division of BioMedical Sciences (Neurosciences), Memorial University of Newfoundland, St. John's, NL, Canada
| | | | - Ryan M Heistad
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, GB41 HSB, 107 Wiggins Rd., Saskatoon, SK, S7N 5E5, Canada
| | - Kaeli J Knudsen
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, GB41 HSB, 107 Wiggins Rd., Saskatoon, SK, S7N 5E5, Canada
| | - Paul R Pennington
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, GB41 HSB, 107 Wiggins Rd., Saskatoon, SK, S7N 5E5, Canada
| | - Josef Buttigieg
- Department of Biology, University of Regina, Regina, SK, Canada
| | | | - Scot C Leary
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Matthew P Parsons
- Division of BioMedical Sciences (Neurosciences), Memorial University of Newfoundland, St. John's, NL, Canada
| | - Darrell D Mousseau
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, GB41 HSB, 107 Wiggins Rd., Saskatoon, SK, S7N 5E5, Canada.
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14
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George EK, Reddy PH. Can Healthy Diets, Regular Exercise, and Better Lifestyle Delay the Progression of Dementia in Elderly Individuals? J Alzheimers Dis 2020; 72:S37-S58. [PMID: 31227652 DOI: 10.3233/jad-190232] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by memory loss and multiple cognitive impairments. Current healthcare costs for over 50 million people afflicted with AD are about $818 million and are projected to be $2 billion by 2050. Unfortunately, there are no drugs currently available that can delay and/or prevent the progression of disease in elderly individuals and in AD patients. Loss of synapses and synaptic damage are largely correlated with cognitive decline in AD patients. Women are at a higher lifetime risk of developing AD encompassing two-thirds of the total AD afflicted population. Only about 1-2% of total AD patients can be explained by genetic mutations in APP, PS1, and PS2 genes. Several risk factors have been identified, such as Apolipoprotein E4 genotype, type 2 diabetes, traumatic brain injury, depression, and hormonal imbalance, are reported to be associated with late-onset AD. Strong evidence reveals that antioxidant enriched diets and regular exercise reduces toxic radicals, enhances mitochondrial function and synaptic activity, and improves cognitive function in elderly populations. Current available data on the use of antioxidants in mouse models of AD and antioxidant(s) supplements in diets of elderly individuals were investigated. The use of antioxidants in randomized clinical trials in AD patients was also critically assessed. Based on our survey of current literature and findings, we cautiously conclude that healthy diets, regular exercise, and improved lifestyle can delay dementia progression and reduce the risk of AD in elderly individuals and reverse subjects with mild cognitive impairment to a non-demented state.
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Affiliation(s)
| | - P Hemachandra Reddy
- Internal Medicine Department, Texas Tech University Health Sciences Center, Lubbock, TX, USA.,Garrison Institute on Aging, Texas Tech University Health Sciences Center, Lubbock, TX, USA.,Garrison Institute on Aging, South West Campus, Texas Tech University Health Sciences Center, Lubbock, TX, USA.,Pharmacology & Neuroscience Department, Texas Tech University Health Sciences Center, Lubbock, TX, USA.,Neurology Department, Texas Tech University Health Sciences Center, Lubbock, TX, USA.,Speech, Language and Hearing Sciences Department, Texas Tech University Health Sciences Center, Lubbock, TX, USA.,Department of Public Health, Graduate School of Biomedical Sciences, Lubbock, TX, USA
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15
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Butterfield DA, Boyd-Kimball D. Redox proteomics and amyloid β-peptide: insights into Alzheimer disease. J Neurochem 2019; 151:459-487. [PMID: 30216447 PMCID: PMC6417976 DOI: 10.1111/jnc.14589] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 08/15/2018] [Accepted: 09/07/2018] [Indexed: 12/12/2022]
Abstract
Alzheimer disease (AD) is a progressive neurodegenerative disorder associated with aging and characterized pathologically by the presence of senile plaques, neurofibrillary tangles, and neurite and synapse loss. Amyloid beta-peptide (1-42) [Aβ(1-42)], a major component of senile plaques, is neurotoxic and induces oxidative stress in vitro and in vivo. Redox proteomics has been used to identify proteins oxidatively modified by Aβ(1-42) in vitro and in vivo. In this review, we discuss these proteins in the context of those identified to be oxidatively modified in animal models of AD, and human studies including familial AD, pre-clinical AD (PCAD), mild cognitive impairment (MCI), early AD, late AD, Down syndrome (DS), and DS with AD (DS/AD). These redox proteomics studies indicate that Aβ(1-42)-mediated oxidative stress occurs early in AD pathogenesis and results in altered antioxidant and cellular detoxification defenses, decreased energy yielding metabolism and mitochondrial dysfunction, excitotoxicity, loss of synaptic plasticity and cell structure, neuroinflammation, impaired protein folding and degradation, and altered signal transduction. Improved access to biomarker imaging and the identification of lifestyle interventions or treatments to reduce Aβ production could be beneficial in preventing or delaying the progression of AD. This article is part of the special issue "Proteomics".
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Affiliation(s)
- D. Allan Butterfield
- Department of Chemistry and Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40506
| | - Debra Boyd-Kimball
- Department of Chemistry and Biochemistry, University of Mount Union, Alliance, OH 44601
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16
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Zhang L, Fernandez-Kim SO, Beckett TL, Niedowicz DM, Kohler K, Dasuri K, Bruce-Keller AJ, Murphy MP, Keller JN. The db mutation improves memory in younger mice in a model of Alzheimer's disease. Biochim Biophys Acta Mol Basis Dis 2019; 1865:2157-2167. [PMID: 31034991 DOI: 10.1016/j.bbadis.2019.04.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 12/20/2018] [Accepted: 01/06/2019] [Indexed: 01/09/2023]
Abstract
Alzheimer's disease (AD) is the most common age-related neurodegenerative disease, while obesity is a major global public health problem associated with the metabolic disorder type 2 diabetes mellitus (T2DM). Chronic obesity and T2DM have been identified as invariant risk factors for dementia and late-onset AD, while their impacts on the occurrence and development of AD remain unclear. As shown in our previous study, the diabetic mutation (db, Leprdb/db) induces mixed or vascular dementia in mature to middle-aged APPΔNL/ΔNL x PS1P264L/P264L knock-in mice (db/AD). In the present study, the impacts of the db mutation on young AD mice at 10 weeks of age were evaluated. The db mutation not only conferred young AD mice with severe obesity, impaired glucose regulation and activated mammalian target of rapamycin (mTOR) signaling pathway in the mouse cortex, but lead to a surprising improvement in memory. At this young age, mice also had decreased cerebral Aβ content, which we have not observed at older ages. This was unlikely to be related to altered Aβ synthesis, as both β- and γ-secretase were unchanged. The db mutation also reduced the cortical IL-1β mRNA level and IBA1 protein level in young AD mice, with no significant effect on the activation of microglia and astrocytes. We conclude that the db mutation could transitorily improve the memory of young AD mice, a finding that may be partially explained by the relatively improved glucose homeostasis in the brains of db/AD mice compared to their counterpart AD mice, suggesting that glucose regulation could be a strategy for prevention and treatment of neurodegenerative diseases like AD.
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Affiliation(s)
- Le Zhang
- Institute of Gerontology, Department of Geriatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 JieFang Avenue, Wuhan, Hubei 430030, China; Institute for Dementia Research and Prevention, Pennington Biomedical Research Center/LSU System, 6400 Perkins Road, Baton Rouge, LA 70808, USA.
| | - Sun-Ok Fernandez-Kim
- Institute for Dementia Research and Prevention, Pennington Biomedical Research Center/LSU System, 6400 Perkins Road, Baton Rouge, LA 70808, USA
| | - Tina L Beckett
- Sanders Brown Center on Aging, University of Kentucky, 800 S. Limestone, Sanders Brown 211, Lexington, KY 40536-0230, USA; Department of Molecular and Cellular Biochemistry, University of Kentucky, 800 S. Limestone, Sanders Brown 211, Lexington, KY 40536-0230, USA
| | - Dana M Niedowicz
- Sanders Brown Center on Aging, University of Kentucky, 800 S. Limestone, Sanders Brown 211, Lexington, KY 40536-0230, USA; Department of Molecular and Cellular Biochemistry, University of Kentucky, 800 S. Limestone, Sanders Brown 211, Lexington, KY 40536-0230, USA
| | - Katharina Kohler
- Sanders Brown Center on Aging, University of Kentucky, 800 S. Limestone, Sanders Brown 211, Lexington, KY 40536-0230, USA; Department of Molecular and Cellular Biochemistry, University of Kentucky, 800 S. Limestone, Sanders Brown 211, Lexington, KY 40536-0230, USA
| | - Kalavathi Dasuri
- Institute for Dementia Research and Prevention, Pennington Biomedical Research Center/LSU System, 6400 Perkins Road, Baton Rouge, LA 70808, USA
| | - Annadora J Bruce-Keller
- Institute for Dementia Research and Prevention, Pennington Biomedical Research Center/LSU System, 6400 Perkins Road, Baton Rouge, LA 70808, USA
| | - M Paul Murphy
- Sanders Brown Center on Aging, University of Kentucky, 800 S. Limestone, Sanders Brown 211, Lexington, KY 40536-0230, USA; Department of Molecular and Cellular Biochemistry, University of Kentucky, 800 S. Limestone, Sanders Brown 211, Lexington, KY 40536-0230, USA.
| | - Jeffrey N Keller
- Institute for Dementia Research and Prevention, Pennington Biomedical Research Center/LSU System, 6400 Perkins Road, Baton Rouge, LA 70808, USA.
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17
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Sri S, Pegasiou CM, Cave CA, Hough K, Wood N, Gomez-Nicola D, Deinhardt K, Bannerman D, Perry VH, Vargas-Caballero M. Emergence of synaptic and cognitive impairment in a mature-onset APP mouse model of Alzheimer's disease. Acta Neuropathol Commun 2019; 7:25. [PMID: 30795807 PMCID: PMC6387506 DOI: 10.1186/s40478-019-0670-1] [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: 12/19/2018] [Accepted: 01/29/2019] [Indexed: 01/10/2023] Open
Abstract
The synaptic changes underlying the onset of cognitive impairment in Alzheimer’s disease (AD) are poorly understood. In contrast to the well documented inhibition of long-term potentiation (LTP) in CA3-CA1 synapses by acute Aβ application in adult neurons from rodents, young amyloid precursor protein (APP) transgenic mouse models often, surprisingly, show normal LTP. This suggests that there may be important differences between mature-onset and developmental-onset APP expression/ Aβ accumulation and the ensuing synaptic and behavioural phenotype. Here, in agreement with previous studies, we observed that developmental expression of APPSw,Ind (3–4 month old mice from line 102, PLoS Med 2:e355, 2005), resulted in reduced basal synaptic transmission in CA3-CA1 synapses, normal LTP, impaired spatial working memory, but normal spatial reference memory. To analyse early Aβ-mediated synaptic dysfunction and cognitive impairment in a more mature brain, we used controllable mature-onset APPSw,Ind expression in line 102 mice. Within 3 weeks of mature-onset APPSw,Ind expression and Aβ accumulation, we detected the first synaptic dysfunction: an impairment of LTP in hippocampal CA3-CA1 synapses. Cognitively, at this time point, we observed a deficit in short-term memory. A reduction in basal synaptic strength and deficit in long-term associative spatial memory were only evident following 12 weeks of APPSw,Ind expression. Importantly, the plasticity impairment observed after 3 weeks of mature-onset APP expression is reversible. Together, these findings demonstrate important differences between developmental and mature-onset APP expression. Further research targeted at this early stage of synaptic dysfunction could help identify mechanisms to treat cognitive impairment in mild cognitive impairment (MCI) and early AD.
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Macheda T, Roberts K, Lyons DN, Higgins E, Ritter KJ, Lin AL, Alilain WJ, Bachstetter AD. Chronic Intermittent Hypoxia Induces Robust Astrogliosis in an Alzheimer's Disease-Relevant Mouse Model. Neuroscience 2018; 398:55-63. [PMID: 30529693 DOI: 10.1016/j.neuroscience.2018.11.040] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 11/19/2018] [Accepted: 11/27/2018] [Indexed: 12/17/2022]
Abstract
Sleep disturbances are a common early symptom of neurodegenerative diseases, including Alzheimer's disease (AD) and other age-related dementias, and emerging evidence suggests that poor sleep may be an important contributor to development of amyloid pathology. Of the causes of sleep disturbances, it is estimated that 10-20% of adults in the United States have sleep-disordered breathing (SDB) disorder, with obstructive sleep apnea accounting for the majority of the SBD cases. The clinical and epidemiological data clearly support a link between sleep apnea and AD; yet, almost no experimental research is available exploring the mechanisms associated with this correlative link. Therefore, we exposed an AD-relevant mouse model (APP/PS1 KI) to chronic intermittent hypoxia (IH) (an experimental model of sleep apnea) to begin to describe one of the potential mechanisms by which SDB could increase the risk of dementia. Previous studies have found that astrogliosis is a contributor to neuropathology in models of chronic IH and AD; therefore, we hypothesized that a reactive astrocyte response might be a contributing mechanism in the neuroinflammation associated with sleep apnea. To test this hypothesis, 10-11-month-old wild-type (WT) and APP/PS1 KI mice were exposed to 10 hours of IH, daily for four weeks. At the end of four weeks brains were analyzed from amyloid burden and astrogliosis. No effect was found for chronic IH exposure on amyloid-beta levels or plaque load in the APP/PS1 KI mice. A significant increase in GFAP staining was found in the APP/PS1 KI mice following chronic IH exposure, but not in the WT mice. Profiling of genes associated with different phenotypes of astrocyte activation identified GFAP, CXCL10, and Ggta1 as significant responses activated in the APP/PS1 KI mice exposed to chronic IH.
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Affiliation(s)
- Teresa Macheda
- Spinal Cord & Brain Injury Research Center, University of Kentucky, Lexington, KY, United States; Department of Neuroscience, University of Kentucky, Lexington, KY, United States
| | - Kelly Roberts
- Spinal Cord & Brain Injury Research Center, University of Kentucky, Lexington, KY, United States; Department of Neuroscience, University of Kentucky, Lexington, KY, United States
| | - Danielle N Lyons
- Spinal Cord & Brain Injury Research Center, University of Kentucky, Lexington, KY, United States; Department of Neuroscience, University of Kentucky, Lexington, KY, United States
| | - Emma Higgins
- Spinal Cord & Brain Injury Research Center, University of Kentucky, Lexington, KY, United States; Department of Neuroscience, University of Kentucky, Lexington, KY, United States
| | - Kyle J Ritter
- Spinal Cord & Brain Injury Research Center, University of Kentucky, Lexington, KY, United States; Department of Neuroscience, University of Kentucky, Lexington, KY, United States
| | - Ai-Ling Lin
- Sanders Brown Center on Aging, University of Kentucky, Lexington, KY, United States; Department of Nutrition and Pharmacology, University of Kentucky, Lexington, KY, United States
| | - Warren J Alilain
- Spinal Cord & Brain Injury Research Center, University of Kentucky, Lexington, KY, United States; Department of Neuroscience, University of Kentucky, Lexington, KY, United States
| | - Adam D Bachstetter
- Spinal Cord & Brain Injury Research Center, University of Kentucky, Lexington, KY, United States; Department of Neuroscience, University of Kentucky, Lexington, KY, United States.
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Jarvela TS, Womack T, Georgiou P, Gould TD, Eriksen JL, Lindberg I. 7B2 chaperone knockout in APP model mice results in reduced plaque burden. Sci Rep 2018; 8:9813. [PMID: 29955078 PMCID: PMC6023903 DOI: 10.1038/s41598-018-28031-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 06/08/2018] [Indexed: 01/18/2023] Open
Abstract
Impairment of neuronal proteostasis is a hallmark of Alzheimer's and other neurodegenerative diseases. However, the underlying molecular mechanisms leading to pathogenic protein aggregation, and the role of secretory chaperone proteins in this process, are poorly understood. We have previously shown that the neural-and endocrine-specific secretory chaperone 7B2 potently blocks in vitro fibrillation of Aβ42. To determine whether 7B2 can function as a chaperone in vivo, we measured plaque formation and performed behavioral assays in 7B2-deficient mice in an hAPPswe/PS1dE9 Alzheimer's model mouse background. Surprisingly, immunocytochemical analysis of cortical levels of thioflavin S- and Aβ-reactive plaques showed that APP mice with a partial or complete lack of 7B2 expression exhibited a significantly lower number and burden of thioflavin S-reactive, as well as Aβ-immunoreactive, plaques. However, 7B2 knockout did not affect total brain levels of either soluble or insoluble Aβ. While hAPP model mice performed poorly in the Morris water maze, their brain 7B2 levels did not impact performance. Since 7B2 loss reduced amyloid plaque burden, we conclude that brain 7B2 can impact Aβ disposition in a manner that facilitates plaque formation. These results are reminiscent of prior findings in hAPP model mice lacking the ubiquitous secretory chaperone clusterin.
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Affiliation(s)
- Timothy S Jarvela
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Tasha Womack
- Department of Pharmacology, College of Pharmacy, University of Houston, Houston, TX, USA
| | - Polymnia Georgiou
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Todd D Gould
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Jason L Eriksen
- Department of Pharmacology, College of Pharmacy, University of Houston, Houston, TX, USA
| | - Iris Lindberg
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA.
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Calcineurin/NFAT Signaling in Activated Astrocytes Drives Network Hyperexcitability in Aβ-Bearing Mice. J Neurosci 2017; 37:6132-6148. [PMID: 28559377 DOI: 10.1523/jneurosci.0877-17.2017] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 05/12/2017] [Accepted: 05/16/2017] [Indexed: 12/25/2022] Open
Abstract
Hyperexcitable neuronal networks are mechanistically linked to the pathologic and clinical features of Alzheimer's disease (AD). Astrocytes are a primary defense against hyperexcitability, but their functional phenotype during AD is poorly understood. Here, we found that activated astrocytes in the 5xFAD mouse model were strongly associated with proteolysis of the protein phosphatase calcineurin (CN) and the elevated expression of the CN-dependent transcription factor nuclear factor of activated T cells 4 (NFAT4). Intrahippocampal injections of adeno-associated virus vectors containing the astrocyte-specific promoter Gfa2 and the NFAT inhibitory peptide VIVIT reduced signs of glutamate-mediated hyperexcitability in 5xFAD mice, measured in vivo with microelectrode arrays and ex vivo brain slices, using whole-cell voltage clamp. VIVIT treatment in 5xFAD mice led to increased expression of the astrocytic glutamate transporter GLT-1 and to attenuated changes in dendrite morphology, synaptic strength, and NMDAR-dependent responses. The results reveal astrocytic CN/NFAT4 as a key pathologic mechanism for driving glutamate dysregulation and neuronal hyperactivity during AD.SIGNIFICANCE STATEMENT Neuronal hyperexcitability and excitotoxicity are increasingly recognized as important mechanisms for neurodegeneration and dementia associated with Alzheimer's disease (AD). Astrocytes are profoundly activated during AD and may lose their capacity to regulate excitotoxic glutamate levels. Here, we show that a highly active calcineurin (CN) phosphatase fragment and its substrate transcription factor, nuclear factor of activated T cells (NFAT4), appear in astrocytes in direct proportion to the extent of astrocyte activation. The blockade of astrocytic CN/NFAT signaling in a common mouse model of AD, using adeno-associated virus vectors normalized glutamate signaling dynamics, increased astrocytic glutamate transporter levels and alleviated multiple signs of neuronal hyperexcitability. The results suggest that astrocyte activation drives hyperexcitability during AD through a mechanism involving aberrant CN/NFAT signaling and impaired glutamate transport.
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21
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Scheff SW, Ansari MA, Mufson EJ. Oxidative stress and hippocampal synaptic protein levels in elderly cognitively intact individuals with Alzheimer's disease pathology. Neurobiol Aging 2016; 42:1-12. [PMID: 27143416 DOI: 10.1016/j.neurobiolaging.2016.02.030] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 02/26/2016] [Accepted: 02/28/2016] [Indexed: 12/11/2022]
Abstract
Neuritic amyloid plaques and neurofibrillary tangles are hallmarks of Alzheimer's disease (AD) and are major components used for the clinical diagnosis of this disorder. However, many individuals with no cognitive impairment (NCI) also present at autopsy with high levels of these AD pathologic hallmarks. In this study, we evaluated 15 autopsy cases from NCI individuals with high levels of AD-like pathology (high pathology no cognitive impairment) and compared them to age- and postmortem-matched cohorts of individuals with amnestic mild cognitive impairment and NCI cases with low AD-like pathology (low pathology no cognitive impairment [LPNCI]). Individuals classified as high pathology no cognitive impairment or amnestic mild cognitive impairment had a significant loss of both presynaptic and postsynaptic proteins in the hippocampus compared with those in the LPNCI cohort. In addition, these 2 groups had a significant increase in 3 different markers of oxidative stress compared with that in the LPNCI group. The changes in levels of synaptic proteins are strongly associated with levels of oxidative stress. These data suggest that cognitively older subjects without dementia but with increased levels of AD-like pathology may represent a very early preclinical stage of AD.
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Affiliation(s)
- Stephen W Scheff
- Department of Anatomy and Neurobiology, Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA.
| | - Mubeen A Ansari
- Department of Anatomy and Neurobiology, Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Elliott J Mufson
- Department of Neurobiology, Barrow Neurological Institute, Phoenix, AZ, USA
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Qosa H, Mohamed LA, Batarseh YS, Alqahtani S, Ibrahim B, LeVine H, Keller JN, Kaddoumi A. Extra-virgin olive oil attenuates amyloid-β and tau pathologies in the brains of TgSwDI mice. J Nutr Biochem 2015; 26:1479-90. [PMID: 26344778 PMCID: PMC4679638 DOI: 10.1016/j.jnutbio.2015.07.022] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Revised: 07/17/2015] [Accepted: 07/20/2015] [Indexed: 12/28/2022]
Abstract
Extra-virgin olive oil (EVOO) is one of the main elements of Mediterranean diet. Several studies have suggested that EVOO has several health promoting effects that could protect from and decrease the risk of Alzheimer's disease (AD). In this study, we investigated the effect of consumption of EVOO-enriched diet on amyloid- and tau-related pathological alterations that are associated with the progression of AD and cerebral amyloid angiopathy (CAA) in TgSwDI mice. Feeding mice with EVOO-enriched diet for 6months, beginning at an age before amyloid-β (Aβ) accumulation starts, has significantly reduced total Aβ and tau brain levels with a significant improvement in mouse cognitive behavior. This reduction in brain Aβ was explained by the enhanced Aβ clearance pathways and reduced brain production of Aβ via modulation of amyloid-β precursor protein processing. On the other hand, although feeding mice with EVOO-enriched diet for 3months, beginning at an age after Aβ accumulation starts, showed improved clearance across the blood-brain barrier and significant reduction in Aβ levels, it did not affect tau levels or improve cognitive functions of TgSwDI mouse. Collectively, results of this study suggest that the long-term consumption of EVOO-containing diet starting at early age provides a protective effect against AD and its related disorder CAA.
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Affiliation(s)
- Hisham Qosa
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, University of Louisiana at Monroe, Monroe, LA 71209, USA
| | - Loqman A Mohamed
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, University of Louisiana at Monroe, Monroe, LA 71209, USA
| | - Yazan S Batarseh
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, University of Louisiana at Monroe, Monroe, LA 71209, USA
| | - Saeed Alqahtani
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, University of Louisiana at Monroe, Monroe, LA 71209, USA
| | - Baher Ibrahim
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, University of Louisiana at Monroe, Monroe, LA 71209, USA
| | - Harry LeVine
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40506, USA
| | - Jeffrey N Keller
- Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Amal Kaddoumi
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, University of Louisiana at Monroe, Monroe, LA 71209, USA.
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Scheff SW, Price DA, Ansari MA, Roberts KN, Schmitt FA, Ikonomovic MD, Mufson EJ. Synaptic change in the posterior cingulate gyrus in the progression of Alzheimer's disease. J Alzheimers Dis 2015; 43:1073-90. [PMID: 25147118 DOI: 10.3233/jad-141518] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Mild cognitive impairment (MCI) is considered to be an early stage in the progression of Alzheimer's disease (AD) providing an opportunity to investigate brain pathogenesis prior to the onset of dementia. Neuroimaging studies have identified the posterior cingulate gyrus (PostC) as a cortical region affected early in the onset of AD. This association cortex is involved in a variety of different cognitive tasks and is intimately connected with the hippocampal/entorhinal cortex region, a component of the medial temporal memory circuit that displays early AD pathology. We quantified the total number of synapses in lamina 3 of the PostC using unbiased stereology coupled with electron microscopy from short postmortem autopsy tissue harvested from cases at different stage of AD progression. Individuals in the early stages of AD showed a significant decline in synaptic numbers compared to individuals with no cognitive impairment (NCI). Subjects with MCI exhibited synaptic numbers that were between the AD and NCI cohorts. Adjacent tissue was evaluated for changes in both pre and postsynaptic proteins levels. Individuals with MCI demonstrated a significant loss in presynaptic markers synapsin-1 and synaptophysin and postsynaptic markers PSD-95 and SAP-97. Levels of [3H]PiB binding was significantly increased in MCI and AD and correlated strongly with levels of synaptic proteins. All synaptic markers showed a significant association with Mini-Mental Status Examination scores. These results support the idea that the PostC synaptic function is affected during the prodromal stage of the disease and may underlie some of the early clinical sequelae associated with AD.
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Affiliation(s)
- Stephen W Scheff
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Douglas A Price
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Mubeen A Ansari
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Kelly N Roberts
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | | | - Milos D Ikonomovic
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA Geriatric Research Educational and Clinical Center, V.A. Pittsburgh Healthcare System, Pittsburgh, PA, USA
| | - Elliott J Mufson
- Rush University Medical Center, Department of Neurological Sciences, Chicago, IL, USA
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Darlington D, Li S, Hou H, Habib A, Tian J, Gao Y, Ehrhart J, Sanberg PR, Sawmiller D, Giunta B, Mori T, Tan J. Human umbilical cord blood-derived monocytes improve cognitive deficits and reduce amyloid-β pathology in PSAPP mice. Cell Transplant 2015; 24:2237-50. [PMID: 26230612 DOI: 10.3727/096368915x688894] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Alzheimer's disease (AD) is the fourth major cause of mortality in the elderly in the US and the leading cause of dementia worldwide. While pharmacological targets have been discovered, there are no true disease-modifying therapies. We have recently discovered that multiple low-dose infusions of human umbilical cord blood cells (HUCBCs) ameliorate cognitive impairments and reduce Aβ-associated neuropathology in PSAPP transgenic mice. However, the mechanism for these effects of HUCBCs remains unclear. In the present study, we examined whether monocytes, as important components of HUCBCs, would have beneficial outcomes on the reduction of AD-like pathology and associated cognitive impairments in PSAPP transgenic AD model mice. PSAPP mice and their wild-type littermates were treated monthly with an infusion of peripheral human umbilical cord blood cell (HUCBC)-derived monocytes over a period of 2 and 4 months, followed by behavioral evaluations, biochemical, and histological analyses. The principal findings of the present study confirmed that monocytes derived from HUCBCs (CB-M) play a central role in HUCBC-mediated cognition-enhancing and Aβ pathology-ameliorating activities. Most importantly, we found that compared with CB-M, aged monocytes showed an ineffective phagocytosis of Aβ, while exogenous soluble amyloid precursor protein α (sAPPα) could reverse this deficiency. Pretreating monocytes with sAPPα upregulates Aβ internalization. Our further studies suggested that sAPPα could form a heterodimer with Aβs, with the APP672-688 (Aβ1-16) region being responsible for this effect. This in turn promoted binding of these heterodimers to monocyte scavenger receptors and thus promoted enhanced Aβ clearance. In summary, our findings suggest an interesting hypothesis that peripheral monocytes contribute to Aβ clearance through heterodimerization of sAPPα with Aβ. Further, declined or impaired sAPPα production, or reduced heterodimerization with Aβ, would cause a deficiency in Aβ clearance and thus accelerate the pathogenesis of AD.
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Affiliation(s)
- Donna Darlington
- Rashid Laboratory for Developmental Neurobiology, Silver Child Development Center, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
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Holler CJ, Davis PR, Beckett TL, Platt TL, Webb RL, Head E, Murphy MP. Bridging integrator 1 (BIN1) protein expression increases in the Alzheimer's disease brain and correlates with neurofibrillary tangle pathology. J Alzheimers Dis 2015; 42:1221-7. [PMID: 25024306 DOI: 10.3233/jad-132450] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Recent genome wide association studies have implicated bridging integrator 1 (BIN1) as a late-onset Alzheimer's disease (AD) susceptibility gene. There are at least 15 different known isoforms of BIN1, with many being expressed in the brain including the longest isoform (iso1), which is brain-specific and localizes to axon initial segments and nodes of Ranvier. It is currently unknown what role BIN1 plays in AD. We analyzed BIN1 protein expression from a large number (n = 71) of AD cases and controls from five different brain regions (hippocampus, inferior parietal cortex, inferior temporal cortex, frontal cortex (BA9), and superior and middle temporal gyri). We found that the amount of the largest isoform of BIN1 was significantly reduced in the AD brain compared to age-matched controls, and smaller BIN1 isoforms were significantly increased. Further, BIN1 was significantly correlated with the amount of neurofibrillary tangle (NFT) pathology but not with either diffuse or neuritic plaques, or with the amount of amyloid-β peptide. BIN1 is known to be abnormally expressed in another human disease, myotonic dystrophy, which also features prominent NFT pathology. These data suggest that BIN1 is likely involved in AD as a modulator of NFT pathology, and that this role may extend to other human diseases that feature tau pathology.
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Affiliation(s)
- Christopher J Holler
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Paulina R Davis
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA Department of Molecular and Biomedical Pharmacology, University of Kentucky, Lexington, KY, USA
| | - Tina L Beckett
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Thomas L Platt
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
| | - Robin L Webb
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Elizabeth Head
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA Department of Molecular and Biomedical Pharmacology, University of Kentucky, Lexington, KY, USA
| | - M Paul Murphy
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA University of Kentucky Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
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26
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Closed head injury in an age-related Alzheimer mouse model leads to an altered neuroinflammatory response and persistent cognitive impairment. J Neurosci 2015; 35:6554-69. [PMID: 25904805 DOI: 10.1523/jneurosci.0291-15.2015] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Epidemiological studies have associated increased risk of Alzheimer's disease (AD)-related clinical symptoms with a medical history of head injury. Currently, little is known about pathophysiology mechanisms linked to this association. Persistent neuroinflammation is one outcome observed in patients after a single head injury. Neuroinflammation is also present early in relevant brain regions during AD pathology progression. In addition, previous mechanistic studies in animal models link neuroinflammation as a contributor to neuropathology and cognitive impairment in traumatic brain injury (TBI) or AD-related models. Therefore, we explored the potential interplay of neuroinflammatory responses in TBI and AD by analysis of the temporal neuroinflammatory changes after TBI in an AD model, the APP/PS1 knock-in (KI) mouse. Discrete temporal aspects of astrocyte, cytokine, and chemokine responses in the injured KI mice were delayed compared with the injured wild-type mice, with a peak neuroinflammatory response in the injured KI mice occurring at 7 d after injury. The neuroinflammatory responses were more persistent in the injured KI mice, leading to a chronic neuroinflammation. At late time points after injury, KI mice exhibited a significant impairment in radial arm water maze performance compared with sham KI mice or injured wild-type mice. Intervention with a small-molecule experimental therapeutic (MW151) that selectively attenuates proinflammatory cytokine production yielded improved cognitive behavior outcomes, consistent with a link between neuroinflammatory responses and altered risk for AD-associated pathology changes with head injury.
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Niedowicz DM, Reeves VL, Platt TL, Kohler K, Beckett TL, Powell DK, Lee TL, Sexton TR, Song ES, Brewer LD, Latimer CS, Kraner SD, Larson KL, Ozcan S, Norris CM, Hersh LB, Porter NM, Wilcock DM, Murphy MP. Obesity and diabetes cause cognitive dysfunction in the absence of accelerated β-amyloid deposition in a novel murine model of mixed or vascular dementia. Acta Neuropathol Commun 2014; 2:64. [PMID: 24916066 PMCID: PMC4229778 DOI: 10.1186/2051-5960-2-64] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 06/04/2014] [Indexed: 01/18/2023] Open
Abstract
Mid-life obesity and type 2 diabetes mellitus (T2DM) confer a modest, increased risk for Alzheimer's disease (AD), though the underlying mechanisms are unknown. We have created a novel mouse model that recapitulates features of T2DM and AD by crossing morbidly obese and diabetic db/db mice with APPΔNL/ΔNLx PS1P264L/P264L knock-in mice. These mice (db/AD) retain many features of the parental lines (e.g. extreme obesity, diabetes, and parenchymal deposition of β-amyloid (Aβ)). The combination of the two diseases led to additional pathologies-perhaps most striking of which was the presence of severe cerebrovascular pathology, including aneurysms and small strokes. Cortical Aβ deposition was not significantly increased in the diabetic mice, though overall expression of presenilin was elevated. Surprisingly, Aβ was not deposited in the vasculature or removed to the plasma, and there was no stimulation of activity or expression of major Aβ-clearing enzymes (neprilysin, insulin degrading enzyme, or endothelin-converting enzyme). The db/AD mice displayed marked cognitive impairment in the Morris Water Maze, compared to either db/db or APPΔNLx PS1P264L mice. We conclude that the diabetes and/or obesity in these mice leads to a destabilization of the vasculature, leading to strokes and that this, in turn, leads to a profound cognitive impairment and that this is unlikely to be directly dependent on Aβ deposition. This model of mixed or vascular dementia provides an exciting new avenue of research into the mechanisms underlying the obesity-related risk for age-related dementia, and will provide a useful tool for the future development of therapeutics.
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28
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Bradley-Whitman MA, Timmons MD, Beckett TL, Murphy MP, Lynn BC, Lovell MA. Nucleic acid oxidation: an early feature of Alzheimer's disease. J Neurochem 2013; 128:294-304. [PMID: 24032632 DOI: 10.1111/jnc.12444] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 08/27/2013] [Accepted: 08/30/2013] [Indexed: 12/20/2022]
Abstract
Studies of oxidative damage during the progression of Alzheimer's disease (AD) suggest its central role in disease pathogenesis. To investigate levels of nucleic acid oxidation in both early and late stages of AD, levels of multiple base adducts were quantified in nuclear and mitochondrial DNA from the superior and middle temporal gyri (SMTG), inferior parietal lobule (IPL), and cerebellum (CER) of age-matched normal control subjects, subjects with mild cognitive impairment, preclinical AD, late-stage AD, and non-AD neurological disorders (diseased control; DC) using gas chromatography/mass spectrometry. Median levels of multiple DNA adducts in nuclear and mitochondrial DNA were significantly (p ≤ 0.05) elevated in the SMTG, IPL, and CER in multiple stages of AD and in DC subjects. Elevated levels of fapyguanine and fapyadenine in mitochondrial DNA suggest a hypoxic environment early in the progression of AD and in DC subjects. Overall, these data suggest that oxidative damage is an early event not only in the pathogenesis of AD but is also present in neurodegenerative diseases in general. Levels of oxidized nucleic acids in nDNA and mtDNA were found to be significantly elevated in mild cognitive impairment (MCI), preclinical Alzheimer's disease (PCAD), late-stage AD (LAD), and a pooled diseased control group (DC) of frontotemporal dementia (FTD) and dementia with Lewy bodies (DLB) subjects compared to normal control (NC) subjects. Nucleic acid oxidation peaked early in disease progression and remained elevated. The study suggests nucleic acid oxidation is a general event in neurodegeneration.
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Affiliation(s)
- Melissa A Bradley-Whitman
- Sanders-Brown Center on Aging and Alzheimer's Disease Center, University of Kentucky, Lexington, Kentucky, USA
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29
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MER5101, a novel Aβ1-15:DT conjugate vaccine, generates a robust anti-Aβ antibody response and attenuates Aβ pathology and cognitive deficits in APPswe/PS1ΔE9 transgenic mice. J Neurosci 2013; 33:7027-37. [PMID: 23595760 DOI: 10.1523/jneurosci.5924-12.2013] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Active amyloid-β (Aβ) immunotherapy is under investigation to prevent or treat early Alzheimer's disease (AD). In 2002, a Phase II clinical trial (AN1792) was halted due to meningoencephalitis in ∼6% of the AD patients, possibly caused by a T-cell-mediated immunological response. Thus, generating a vaccine that safely generates high anti-Aβ antibody levels in the elderly is required. In this study, MER5101, a novel conjugate of Aβ1-15 peptide (a B-cell epitope fragment) conjugated to an immunogenic carrier protein, diphtheria toxoid (DT), and formulated in a nanoparticular emulsion-based adjuvant, was administered to 10-month-old APPswe/PS1ΔE9 transgenic (Tg) and wild-type (Wt) mice. High anti-Aβ antibody levels were observed in both vaccinated APPswe/PS1ΔE9 Tg and Wt mice. Antibody isotypes were mainly IgG1 and IgG2b, suggesting a Th2-biased response. Restimulation of splenocytes with the Aβ1-15:DT conjugate resulted in a strong proliferative response, whereas proliferation was absent after restimulation with Aβ1-15 or Aβ1-40/42 peptides, indicating a cellular immune response against DT while avoiding an Aβ-specific T-cell response. Moreover, significant reductions in cerebral Aβ plaque burden, accompanied by attenuated microglial activation and increased synaptic density, were observed in MER5101-vaccinated APPswe/PS1ΔE9 Tg mice compared with Tg adjuvant controls. Last, MER5101-immunized APPswe/PS1ΔE9 Tg mice showed improvement of cognitive deficits in both contextual fear conditioning and the Morris water maze. Our novel, highly immunogenic Aβ conjugate vaccine, MER5101, shows promise for improving Aβ vaccine safety and efficacy and therefore, may be useful for preventing and/or treating early AD.
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Webster SJ, Bachstetter AD, Van Eldik LJ. Comprehensive behavioral characterization of an APP/PS-1 double knock-in mouse model of Alzheimer's disease. Alzheimers Res Ther 2013; 5:28. [PMID: 23705774 PMCID: PMC3706792 DOI: 10.1186/alzrt182] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 04/29/2013] [Accepted: 05/24/2013] [Indexed: 12/15/2022]
Abstract
INTRODUCTION Despite the extensive mechanistic and pathological characterization of the amyloid precursor protein (APP)/presenilin-1 (PS-1) knock-in mouse model of Alzheimer's disease (AD), very little is known about the AD-relevant behavioral deficits in this model. Characterization of the baseline behavioral performance in a variety of functional tasks and identification of the temporal onset of behavioral impairments are important to provide a foundation for future preclinical testing of AD therapeutics. Here we perform a comprehensive behavioral characterization of this model, discuss how the observed behavior correlates with the mechanistic and pathological observations of others, and compare this model with other commonly used AD mouse models. METHODS FOUR DIFFERENT GROUPS OF MICE RANGING ACROSS THE LIFESPAN OF THIS MODEL (TEST GROUPS: 7, 11, 15, and 24 months old) were run in a behavioral test battery consisting of tasks to assess motor function (grip strength, rotor rod, beam walk, open field ambulatory movement), anxiety-related behavior (open field time spent in peripheral zone vs. center zone, elevated plus maze), and cognitive function (novel object recognition, radial arm water maze). RESULTS There were no differences in motor function or anxiety-related behavior between APP/PS-1 knock-in mice and wild-type counterpart mice for any age group. Cognitive deficits in both recognition memory (novel object recognition) and spatial reference memory (radial arm water maze) became apparent for the knock-in animals as the disease progressed. CONCLUSION This is the first reported comprehensive behavioral analysis of the APP/PS1 knock-in mouse model of AD. The lack of motor/coordination deficits or abnormal anxiety levels, coupled with the age/disease-related cognitive decline and high physiological relevance of this model, make it well suited for utilization in preclinical testing of AD-relevant therapeutics.
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Affiliation(s)
- Scott J Webster
- Sanders-Brown Center on Aging, 800 S. Limestone, University of Kentucky, Lexington, KY 40536, USA
| | - Adam D Bachstetter
- Sanders-Brown Center on Aging, 800 S. Limestone, University of Kentucky, Lexington, KY 40536, USA
| | - Linda J Van Eldik
- Sanders-Brown Center on Aging, 800 S. Limestone, University of Kentucky, Lexington, KY 40536, USA
- Department of Anatomy and Neurobiology, 800 S. Limestone, University of Kentucky, Lexington, KY 40536, USA
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Platt TL, Reeves VL, Murphy MP. Transgenic models of Alzheimer's disease: better utilization of existing models through viral transgenesis. Biochim Biophys Acta Mol Basis Dis 2013; 1832:1437-48. [PMID: 23619198 DOI: 10.1016/j.bbadis.2013.04.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 04/09/2013] [Accepted: 04/11/2013] [Indexed: 12/30/2022]
Abstract
Animal models have been used for decades in the Alzheimer's disease (AD) research field and have been crucial for the advancement of our understanding of the disease. Most models are based on familial AD mutations of genes involved in the amyloidogenic process, such as the amyloid precursor protein (APP) and presenilin 1 (PS1). Some models also incorporate mutations in tau (MAPT) known to cause frontotemporal dementia, a neurodegenerative disease that shares some elements of neuropathology with AD. While these models are complex, they fail to display pathology that perfectly recapitulates that of the human disease. Unfortunately, this level of pre-existing complexity creates a barrier to the further modification and improvement of these models. However, as the efficacy and safety of viral vectors improves, their use as an alternative to germline genetic modification is becoming a widely used research tool. In this review we discuss how this approach can be used to better utilize common mouse models in AD research. This article is part of a Special Issue entitled: Animal Models of Disease.
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Affiliation(s)
- Thomas L Platt
- Department of Cellular and Molecular Biochemistry, University of Kentucky, Lexington, KY 40536, USA
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32
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Beckett TL, Webb RL, Niedowicz DM, Holler CJ, Matveev S, Baig I, LeVine H, Keller JN, Murphy MP. Postmortem Pittsburgh Compound B (PiB) binding increases with Alzheimer's disease progression. J Alzheimers Dis 2013; 32:127-38. [PMID: 22766739 DOI: 10.3233/jad-2012-120655] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The development of imaging reagents is of considerable interest in the Alzheimer's disease (AD) field. Some of these, such as Pittsburgh Compound B (PiB), were designed to bind to the amyloid-β peptide (Aβ), the major component of amyloid deposits in the AD brain. Although these agents were designed for imaging amyloid deposits in vivo, a major avenue of evaluation relies on postmortem cross validation with established indices of AD pathology. In this study, we evaluated changes in the postmortem binding of PiB and its relationship to other aspects of Aβ-related pathology in a series of AD cases and age-matched controls. We also examined cases of preclinical AD (PCAD) and amnestic mild cognitive impairment (MCI), both considered early points in the AD continuum. PiB binding was found to increase with the progression of the disease and paralleled increases in the less soluble forms of Aβ, including SDS-stable Aβ oligomers. Increased PiB binding and its relationship to Aβ was only significant in a brain region vulnerable to the development of AD pathology (the superior and middle temporal gyri) but not in an unaffected region (cerebellum). This implies that the amyloid deposited in disease-affected regions may possess fundamental, brain region specific characteristics that may not as yet be fully appreciated. These data support the idea that PiB is a useful diagnostic tool for AD, particularly in the early stage of the disease, and also show that PiB could be a useful agent for the discovery of novel disease-related properties of amyloid.
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Affiliation(s)
- Tina L Beckett
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536-0230, USA
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33
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Beckett TL, Studzinski CM, Keller JN, Paul Murphy M, Niedowicz DM. A ketogenic diet improves motor performance but does not affect β-amyloid levels in a mouse model of Alzheimer's disease. Brain Res 2013; 1505:61-7. [PMID: 23415649 DOI: 10.1016/j.brainres.2013.01.046] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 01/14/2013] [Accepted: 01/29/2013] [Indexed: 11/25/2022]
Abstract
β-Amyloid (Aβ), a small, fibrillogenic peptide, is known to play an important role in the pathogenesis of Alzheimer's disease (AD) in the brain. In addition, Aβ accumulates in skeletal muscle cells in individuals with sporadic inclusion body myositis (sIBM), an age-related muscle disease. Because of the socioeconomic burden associated with age-related diseases, particularly AD, there has been considerable emphasis on studying potential therapeutic strategies. The high-fat, low carbohydrate ketogenic diet has been used extensively to treat refractory childhood epilepsy and has been studied as a potential treatment for other neurological diseases, including Parkinson's disease and AD. In this study, we fed young APP/PS1 knock-in mice, which have a whole body knock-in of AD-related genes, a ketogenic diet and determined the effect on Aβ levels in the brain and skeletal muscle, as well motor performance and oxidative stress. Aβ and its precursor, the β-C-terminal fragment of amyloid precursor protein (CTFβ), were unchanged overall in both the brain and quadriceps after 1 month on the ketogenic diet, and there was no effect on nitrotyrosine, a product of oxidative stress. The ketogenic diet improved performance on the Rota-rod apparatus (p=0.007), however. These data indicate that the ketogenic diet may have some efficacy in the treatment of both neurologic and muscle diseases though the underlying mechanisms do not involve amelioration of Aβ pathology.
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Affiliation(s)
- Tina L Beckett
- Sanders Brown Center on Aging, University of Kentucky, 800S. Limestone, Lexington, KY 40536-0230, United States
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Targeting astrocytes ameliorates neurologic changes in a mouse model of Alzheimer's disease. J Neurosci 2013; 32:16129-40. [PMID: 23152597 DOI: 10.1523/jneurosci.2323-12.2012] [Citation(s) in RCA: 222] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Astrocytes are the most abundant cell type in the brain and play a critical role in maintaining healthy nervous tissue. In Alzheimer's disease (AD) and most other neurodegenerative disorders, many astrocytes convert to a chronically "activated" phenotype characterized by morphologic and biochemical changes that appear to compromise protective properties and/or promote harmful neuroinflammatory processes. Activated astrocytes emerge early in the course of AD and become increasingly prominent as clinical and pathological symptoms progress, but few studies have tested the potential of astrocyte-targeted therapeutics in an intact animal model of AD. Here, we used adeno-associated virus (AAV) vectors containing the astrocyte-specific Gfa2 promoter to target hippocampal astrocytes in APP/PS1 mice. AAV-Gfa2 vectors drove the expression of VIVIT, a peptide that interferes with the immune/inflammatory calcineurin/NFAT (nuclear factor of activated T-cells) signaling pathway, shown by our laboratory and others to orchestrate biochemical cascades leading to astrocyte activation. After several months of treatment with Gfa2-VIVIT, APP/PS1 mice exhibited improved cognitive and synaptic function, reduced glial activation, and lower amyloid levels. The results confirm a deleterious role for activated astrocytes in AD and lay the groundwork for exploration of other novel astrocyte-based therapies.
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Zhang L, Dasuri K, Fernandez-Kim SO, Bruce-Keller AJ, Freeman LR, Pepping JK, Beckett TL, Murphy MP, Keller JN. Prolonged diet induced obesity has minimal effects towards brain pathology in mouse model of cerebral amyloid angiopathy: implications for studying obesity-brain interactions in mice. Biochim Biophys Acta Mol Basis Dis 2013; 1832:1456-62. [PMID: 23313575 DOI: 10.1016/j.bbadis.2013.01.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 12/30/2012] [Accepted: 01/02/2013] [Indexed: 12/12/2022]
Abstract
Cerebral amyloid angiopathy (CAA) occurs in nearly every individual with Alzheimer's disease (AD) and Down's syndrome, and is the second largest cause of intracerebral hemorrhage. Mouse models of CAA have demonstrated evidence for increased gliosis contributing to CAA pathology. Nearly two thirds of Americans are overweight or obese, with little known about the effects of obesity on the brain, although increasingly the vasculature appears to be a principle target of obesity effects on the brain. In the current study we describe for the first time whether diet induced obesity (DIO) modulates glial reactivity, amyloid levels, and inflammatory signaling in a mouse model of CAA. In these studies we identify surprisingly that DIO does not significantly increase Aβ levels, astrocyte (GFAP) or microglial (IBA-1) gliosis in the CAA mice. However, within the hippocampal gyri a localized increase in reactive microglia were increased in the CA1 and stratum oriens relative to CAA mice on a control diet. DIO was observed to selectively increase IL-6 in CAA mice, with IL-1β and TNF-α not increased in CAA mice in response to DIO. Taken together, these data show that prolonged DIO has only modest effects towards Aβ in a mouse model of CAA, but appears to elevate some localized microglial reactivity within the hippocampal gyri and selective markers of inflammatory signaling. These data are consistent with the majority of the existing literature in other models of Aβ pathology, which surprisingly show a mixed profile of DIO effects towards pathological processes in mouse models of neurodegenerative disease. The importance for considering the potential impact of ceiling effects in pathology within mouse models of Aβ pathogenesis, and the current experimental limitations for DIO in mice to fully replicate metabolic dysfunction present in human obesity, are discussed. This article is part of a Special Issue entitled: Animal Models of Disease.
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Affiliation(s)
- Le Zhang
- Louisiana State University, Baton Rouge, LA 70803, USA
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Niedowicz DM, Beckett TL, Matveev S, Weidner AM, Baig I, Kryscio RJ, Mendiondo MS, LeVine H, Keller JN, Murphy MP. Pittsburgh compound B and the postmortem diagnosis of Alzheimer disease. Ann Neurol 2013; 72:564-70. [PMID: 23109151 DOI: 10.1002/ana.23633] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
OBJECTIVE Deposition of the amyloid-β (Aβ) peptide in neuritic plaques is a requirement for the diagnosis of Alzheimer disease (AD). Although the continued development of in vivo imaging agents such as Pittsburgh compound B (PiB) is promising, the diagnosis of AD is still challenging. This can be partially attributed to our lack of a detailed understanding of the interrelationship between the various pools and species of Aβ and other common indices of AD pathology. We hypothesized that recent advances in our ability to accurately measure Aβ postmortem (for example, using PiB), could form the basis of a simple means to deliver an accurate AD diagnosis. METHODS We conducted a comprehensive analysis of the amount of Aβ40 and Aβ42 in increasingly insoluble fractions, oligomeric Aβ, and fibrillar Aβ (as defined by PiB binding), as well as plaques (diffuse and neuritic), and neurofibrillary tangles in autopsy specimens from age-matched, cognitively normal controls (n = 23) and AD (n = 22) cases, across multiple brain regions. RESULTS Both PiB binding and the amount of sodium dodecyl sulfate (SDS)-soluble Aβ were able to predict disease status; however, SDS-soluble Aβ was a better measure. Oligomeric Aβ was not a predictor of disease status. PiB binding was strongly related to plaque count, although diffuse plaques were a stronger correlate than neuritic plaques. INTERPRETATION Although postmortem PiB binding was somewhat useful in distinguishing AD from control cases, SDS-soluble Aβ measured by standard immunoassay was substantially better. These findings have important implications for the development of imaging-based biomarkers of AD.
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Affiliation(s)
- Dana M Niedowicz
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536-0230, USA
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Niedowicz DM, Studzinski CM, Weidner AM, Platt TL, Kingry KN, Beckett TL, Bruce-Keller AJ, Keller JN, Murphy MP. Leptin regulates amyloid β production via the γ-secretase complex. Biochim Biophys Acta Mol Basis Dis 2012; 1832:439-44. [PMID: 23274884 DOI: 10.1016/j.bbadis.2012.12.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Revised: 12/17/2012] [Accepted: 12/19/2012] [Indexed: 12/11/2022]
Abstract
Alzheimer's disease (AD) is the most common age-related neurodegenerative disease, affecting an estimated 5.3million people in the United States. While many factors likely contribute to AD progression, it is widely accepted that AD is driven by the accumulation of β-amyloid (Aβ), a small, fibrillogenic peptide generated by the sequential proteolysis of the amyloid precursor protein by the β- and γ-secretases. Though the underlying causes of Aβ accumulation in sporadic AD are myriad, it is clear that lifestyle and overall health play a significant role. The adipocyte-derived hormone leptin has varied systemic affects, including neuropeptide release and neuroprotection. A recent study by Lieb et al. (2009) showed that individuals with low plasma leptin levels are at greater risk of developing AD, through unknown mechanisms. In this report, we show that plasma leptin is a strong negative predictor of Aβ levels in the mouse brain, supporting a protective role for the hormone in AD onset. We also show that the inhibition of Aβ accumulation is due to the downregulation of transcription of the γ-secretase components. On the other hand, β-secretase expression is either unchanged (BACE1) or increased (BACE2). Finally, we show that only presenilin 1 (PS1) is negatively correlated with plasma leptin at the protein level (p<0.0001). These data are intriguing and may highlight a role for leptin in regulating the onset of amyloid pathology and AD.
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Early stage drug treatment that normalizes proinflammatory cytokine production attenuates synaptic dysfunction in a mouse model that exhibits age-dependent progression of Alzheimer's disease-related pathology. J Neurosci 2012; 32:10201-10. [PMID: 22836255 DOI: 10.1523/jneurosci.1496-12.2012] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Overproduction of proinflammatory cytokines in the CNS has been implicated as a key contributor to pathophysiology progression in Alzheimer's disease (AD), and extensive studies with animal models have shown that selective suppression of excessive glial proinflammatory cytokines can improve neurologic outcomes. The prior art, therefore, raises the logical postulation that intervention with drugs targeting dysregulated glial proinflammatory cytokine production might be effective disease-modifying therapeutics if used in the appropriate biological time window. To test the hypothesis that early stage intervention with such drugs might be therapeutically beneficial, we examined the impact of intervention with MW01-2-151SRM (MW-151), an experimental therapeutic that selectively attenuates proinflammatory cytokine production at low doses. MW-151 was tested in an APP/PS1 knock-in mouse model that exhibits increases in AD-relevant pathology progression with age, including increases in proinflammatory cytokine levels. Drug was administered during two distinct but overlapping therapeutic time windows of early stage pathology development. MW-151 treatment attenuated the increase in microglial and astrocyte activation and proinflammatory cytokine production in the cortex and yielded improvement in neurologic outcomes, such as protection against synaptic protein loss and synaptic plasticity impairment. The results also demonstrate that the therapeutic time window is an important consideration in efficacy studies of drugs that modulate glia biological responses involved in pathology progression and suggest that such paradigms should be considered in the development of new therapeutic regimens that seek to delay the onset or slow the progression of AD.
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Niedowicz DM, Nelson PT, Murphy MP. Alzheimer's disease: pathological mechanisms and recent insights. Curr Neuropharmacol 2012; 9:674-84. [PMID: 22654725 PMCID: PMC3263461 DOI: 10.2174/157015911798376181] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Revised: 06/17/2010] [Accepted: 10/11/2010] [Indexed: 01/26/2023] Open
Abstract
Amyloidopathies cause neurodegeneration in a substantial portion of the elderly population. Improvements in long term health care have made elderly individuals a large and growing demographic group, marking these diseases as a major public health concern. Alzheimer's Disease (AD) is the most studied form of neurodegenerative amyloidopathy. Although our understanding of AD is far from complete, several decades of research have advanced our knowledge to the point where it is conceivable that some form of disease modifying therapy may be available in the near future. These advances have been built on a strong mechanistic understanding of the disease from its underlying genetics, molecular biology and clinical pathology. Insights derived from the study of other neurodegenerative diseases, such as some forms of frontotemporal dementia, have been critical to this process. This knowledge has allowed researchers to construct animal models of the disease process that have paved the way towards the development of therapeutics. However, what was once thought to be a straightforward problem has evolved into a series of disappointing outcomes. Examination of pathways common to all neurodegenerative diseases, including the cellular mechanisms that clear misfolded proteins and their regulation, may be the best way to move forward.
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Affiliation(s)
- Dana M Niedowicz
- Departments of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
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40
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Upadhaya AR, Lungrin I, Yamaguchi H, Fändrich M, Thal DR. High-molecular weight Aβ oligomers and protofibrils are the predominant Aβ species in the native soluble protein fraction of the AD brain. J Cell Mol Med 2012; 16:287-95. [PMID: 21418518 PMCID: PMC3823292 DOI: 10.1111/j.1582-4934.2011.01306.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
Alzheimer’s disease (AD) is characterized by the aggregation and deposition of amyloid β protein (Aβ) in the brain. Soluble Aβ oligomers are thought to be toxic. To investigate the predominant species of Aβ protein that may play a role in AD pathogenesis, we performed biochemical analysis of AD and control brains. Sucrose buffer-soluble brain lysates were characterized in native form using blue native (BN)-PAGE and also in denatured form using SDS-PAGE followed by Western blot analysis. BN-PAGE analysis revealed a high-molecular weight smear (>1000 kD) of Aβ42-positive material in the AD brain, whereas low-molecular weight and monomeric Aβ species were not detected. SDS-PAGE analysis, on the other hand, allowed the detection of prominent Aβ monomer and dimer bands in AD cases but not in controls. Immunoelectron microscopy of immunoprecipitated oligomers and protofibrils/fibrils showed spherical and protofibrillar Aβ-positive material, thereby confirming the presence of high-molecular weight Aβ (hiMWAβ) aggregates in the AD brain. In vitro analysis of synthetic Aβ40- and Aβ42 preparations revealed Aβ fibrils, protofibrils, and hiMWAβ oligomers that were detectable at the electron microscopic level and after BN-PAGE. Further, BN-PAGE analysis exhibited a monomer band and less prominent low-molecular weight Aβ (loMWAβ) oligomers. In contrast, SDS-PAGE showed large amounts of loMWAβ but no hiMWAβ40 and strikingly reduced levels of hiMWAβ42. These results indicate that hiMWAβ aggregates, particularly Aβ42 species, are most prevalent in the soluble fraction of the AD brain. Thus, soluble hiMWAβ aggregates may play an important role in the pathogenesis of AD either independently or as a reservoir for release of loMWAβ oligomers.
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Affiliation(s)
- Ajeet Rijal Upadhaya
- Laboratory of Neuropathology-Institute of Pathology, Center for Clinical Research at the University of Ulm, Ulm, Germany
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Effects of aging and genotype on circadian rhythms, sleep, and clock gene expression in APPxPS1 knock-in mice, a model for Alzheimer's disease. Exp Neurol 2012; 236:249-58. [PMID: 22634208 DOI: 10.1016/j.expneurol.2012.05.011] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 04/10/2012] [Accepted: 05/12/2012] [Indexed: 11/21/2022]
Abstract
Profound disruptions of circadian rhythms and sleep/wake cycles constitute a major cause of institutionalization of AD patients. This study investigated whether a rodent model of AD, APP(NLH/NLH)/PS-1(P264L/264L) (APPxPS1) mice, exhibits circadian alterations. The APPxPS1 mice were generated using CD-1/129 mice and Cre-lox knock-in technology to "humanize" the mouse amyloid (A)β sequence and create a presenilin-1 mutation identified in familial early-onset AD patients. APPxPS1 and WT mice of several ages (~4, 11, and 15 months) were monitored for circadian rhythms in wheel running, cage activity, and sleep:wake behavior. After rhythm assessment, the mice were euthanized at zeitgeber time (ZT) 2 or 10 (i.e., 2 or 10 h after lights-on) and brains were dissected. Amyloidβ levels were measured in cortical samples and brain sections of the hypothalamus and hippocampus were prepared and used for in situ hybridization of circadian or neuropeptide genes. The most significant effects of the APPxPS1 transgenes were phase delays of ~2 h in the onset of daytime wakefulness bouts (P<0.005) and peak wakefulness (P<0.02), potentially relevant to phase delays previously reported in AD patients. However, genotype did not affect the major activity peaks or phases of wheel running, wake, or general movement, which were bimodal with dominant dawn and dusk activity. Expression of Period 2 in the suprachiasmatic nucleus was affected by ZT (P<0.0001) with a marginal interaction effect of age, genotype, and ZT (P<0.08). A separate analysis of the old animals indicated a robust interaction between ZT and genotype, as well as main effects of these parameters. Aging also altered sleep (e.g., bout length and amount of daytime sleep) and the amount of wheel running and cage activity. In conclusion, the APPxPS1 knock-in mice exhibit some alterations in their sleep:wake rhythm and clock gene expression, but do not show robust, genotype-related changes in activity rhythms. The prominent daytime activity peaks shown by the background strain complicate the use of these APPxPS1 knock-in mice for investigations of circadian activity rhythms in AD. In addition to this unusual activity pattern, lack of hyperactivity differentiates the APPxPS1 knock-in mice from other transgenic AD models.
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42
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LeVine H, Lampe L, Abdelmoti L, Augelli-Szafran CE. Dihydroxybenzoic acid isomers differentially dissociate soluble biotinyl-Aβ(1-42) oligomers. Biochemistry 2011; 51:307-15. [PMID: 22129351 DOI: 10.1021/bi201288x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Polyphenolic compounds including a number of natural products such as resveratrol, curcumin, catechin derivatives, and nordihydroguaiaretic acid have effects on the assembly of Aβ fibrils and oligomers as well as on fibril morphology. Based on a lead structure obtained from a screen of a small molecule diversity library, simple benzoic acid derivatives distinguished by the number and position of hydroxyls on the aromatic ring displayed different abilities to dissociate preformed biotinyl-Aβ(1-42) oligomers. The 2,3-, 2,5-, and 3,4-dihydroxybenzoic acid (DHBA) isomers were active oligomer dissociators. The remaining DHBA isomers and the monohydroxy and unsubstituted benzoic acids were inactive and did not compete with the active compounds to block oligomer dissociation. None of the compounds blocked oligomer assembly, indicating that they do not interact with monomeric Aβ to shift the oligomer-monomer equilibrium. Dissociating activity was not associated with quinone redox cycling capacity of the compounds. Gallic acid (3,4,5-trihydroxybenzoic acid) stabilized biotinyl-Aβ(1-42) oligomers against intrinsic dissociation and blocked the effects of the active dissociators, independent of the concentration of dissociator. A model for the mechanism of action of the DHBA dissociators proposes that these compounds destabilize oligomer structure promoting progressive monomer dissociation rather than fissioning oligomers into smaller, but still macromolecular, species. Gallic acid blocks dissociation by stabilizing oligomers against this process.
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Affiliation(s)
- Harry LeVine
- Department of Cellular and Molecular Biochemistry, Center on Aging, Center for Structural Biology, University of Kentucky, Lexington, Kentucky 40506, United States.
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Robinson RAS, Joshi G, Huang Q, Sultana R, Baker AS, Cai J, Pierce W, St Clair DK, Markesbery WR, Butterfield DA. Proteomic analysis of brain proteins in APP/PS-1 human double mutant knock-in mice with increasing amyloid β-peptide deposition: insights into the effects of in vivo treatment with N-acetylcysteine as a potential therapeutic intervention in mild cognitive impairment and Alzheimer's disease. Proteomics 2011; 11:4243-56. [PMID: 21954051 DOI: 10.1002/pmic.201000523] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 07/21/2011] [Accepted: 08/18/2011] [Indexed: 12/14/2022]
Abstract
Proteomics analyses were performed on the brains of wild-type (WT) controls and an Alzheimer's disease (AD) mouse model, APP/PS-1 human double mutant knock-in mice. Mice were given either drinking water or water supplemented with N-acetylcysteine (NAC) (2 mg/kg body weight) for a period of five months. The time periods of treatment correspond to ages prior to Aβ deposition (i.e. 4-9 months), resembling human mild cognitive impairment (MCI), and after Aβ deposition (i.e. 7-12 months), more closely resembling advancing stages of AD. Substantial differences exist between the proteomes of WT and APP/PS-1 mice at 9 or 12 months, indicating that Aβ deposition and oxidative stress lead to downstream changes in protein expression. Altered proteins are involved in energy-related pathways, excitotoxicity, cell cycle signaling, synaptic abnormalities, and cellular defense and structure. Overall, the proteomic results support the notion that NAC may be beneficial for increasing cellular stress responses in WT mice and for influencing the levels of energy- and mitochondria-related proteins in APP/PS-1 mice.
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Affiliation(s)
- Renã A S Robinson
- Department of Chemistry, University of Kentucky, Lexington, KY 40506, USA
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Weidner AM, Bradley MA, Beckett TL, Niedowicz DM, Dowling ALS, Matveev SV, LeVine H, Lovell MA, Murphy MP. RNA oxidation adducts 8-OHG and 8-OHA change with Aβ42 levels in late-stage Alzheimer's disease. PLoS One 2011; 6:e24930. [PMID: 21949792 PMCID: PMC3176793 DOI: 10.1371/journal.pone.0024930] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 08/24/2011] [Indexed: 12/02/2022] Open
Abstract
While research supports amyloid-β (Aβ) as the etiologic agent of Alzheimer's disease (AD), the mechanism of action remains unclear. Evidence indicates that adducts of RNA caused by oxidation also represent an early phenomenon in AD. It is currently unknown what type of influence these two observations have on each other, if any. We quantified five RNA adducts by gas chromatography/mass spectroscopy across five brain regions from AD cases and age-matched controls. We then used a reductive directed analysis to compare the RNA adducts to common indices of AD neuropathology and various pools of Aβ. Using data from four disease-affected brain regions (Brodmann's Area 9, hippocampus, inferior parietal lobule, and the superior and middle temporal gyri), we found that the RNA adduct 8-hydroxyguanine (8-OHG) decreased, while 8-hydroxyadenine (8-OHA) increased in AD. The cerebellum, which is generally spared in AD, did not show disease related changes, and no RNA adducts correlated with the number of plaques or tangles. Multiple regression analysis revealed that SDS-soluble Aβ42 was the best predictor of changes in 8-OHG, while formic acid-soluble Aβ42 was the best predictor of changes in 8-OHA. This study indicates that although there is a connection between AD related neuropathology and RNA oxidation, this relationship is not straightforward.
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Affiliation(s)
- Adam M. Weidner
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, United States of America
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
| | - Melissa A. Bradley
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, United States of America
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
| | - Tina L. Beckett
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, United States of America
| | - Dana M. Niedowicz
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, United States of America
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
| | - Amy L. S. Dowling
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, United States of America
- Department of Molecular and Biomedical Pharmacology, University of Kentucky, Lexington, Kentucky, United States of America
| | - Sergey V. Matveev
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, United States of America
| | - Harry LeVine
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, United States of America
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
| | - Mark A. Lovell
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, United States of America
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, United States of America
- * E-mail: (MAL); (MPM)
| | - M. Paul Murphy
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, United States of America
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
- * E-mail: (MAL); (MPM)
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Bruce-Keller AJ, Gupta S, Knight AG, Beckett TL, McMullen JM, Davis PR, Murphy MP, Van Eldik LJ, St Clair D, Keller JN. Cognitive impairment in humanized APP×PS1 mice is linked to Aβ(1-42) and NOX activation. Neurobiol Dis 2011; 44:317-26. [PMID: 21798347 DOI: 10.1016/j.nbd.2011.07.012] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 06/11/2011] [Accepted: 07/11/2011] [Indexed: 02/08/2023] Open
Abstract
Cognitive impairment in Alzheimer's disease (AD) is strongly associated with both extensive deposition of amyloid β peptides and oxidative stress, but the exact role of these indices in the development of dementia is not clear. This study was designed to determine the relationship between cognitive impairment, activation of the free radical producing enzyme NADPH oxidase (NOX), and progressive changes in Aβ deposition and solubility in humanized APP×PS1 knock-in mice of increasing age. Data show that cognitive performance and expression of key synaptic proteins were progressively decreased in aging APP×PS1 mice. Likewise, NOX activity and expression of the specific NOX subunit NOX4 were significantly increased in APP×PS1 mice in an age-dependent manner, and NOX activity and cognitive impairment shared a significant linear relationship. Data further show that age-dependent increases in Aβ(1-42) had a significant linear relationship with both NOX activity and cognitive performance in APP×PS1 knock-in mice. Collectively, these data show that NOX expression and activity are significantly upregulated with age in this humanized model of Aβ pathogenesis, and suggest that NOX-associated redox pathways are intimately linked to both the loss of cognitive function and the deposition of Aβ(1-42).
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Affiliation(s)
- Annadora J Bruce-Keller
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA.
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Weidner AM, Housley M, Murphy MP, Levine H. Purified high molecular weight synthetic Aβ(1-42) and biological Aβ oligomers are equipotent in rapidly inducing MTT formazan exocytosis. Neurosci Lett 2011; 497:1-5. [PMID: 21504780 DOI: 10.1016/j.neulet.2011.03.082] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 03/21/2011] [Accepted: 03/28/2011] [Indexed: 11/28/2022]
Abstract
Synthetic soluble Aβ oligomers are often used as a surrogate for biologic material in a number of model systems. We compared the activity of Aβ oligomers (synthetic and cell culture media derived) on the human SH-SY5Y neuroblastoma and C2C12 mouse myoblast cell lines in a novel, modified MTT assay. Separating oligomers from monomeric peptide by size exclusion chromatography produced effects at peptide concentrations approaching physiologic levels (10-100 nM). Purified oligomers, but not monomers or fibrils, elicited an increase of a detergent-insoluble form of MTT formazan within 2h as opposed to a control toxin (H(2)O(2)). This effect was comparable for biological and synthetic peptide in both cell types. Monomeric Aβ attenuated the effect of soluble oligomers. This study suggests that the activities of biological and synthetic oligomers are indistinguishable during early stages of Aβ oligomer-cell interaction.
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Affiliation(s)
- Adam M Weidner
- Department of Cellular and Molecular Biochemistry, Center on Aging, Center for Structural Biology, University of Kentucky, 800 S. Limestone Street, Lexington, KY 40536-0230, United States.
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Abdul HM, Baig I, LeVine H, Guttmann RP, Norris CM. Proteolysis of calcineurin is increased in human hippocampus during mild cognitive impairment and is stimulated by oligomeric Abeta in primary cell culture. Aging Cell 2011; 10:103-13. [PMID: 20969723 PMCID: PMC3021581 DOI: 10.1111/j.1474-9726.2010.00645.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Recent reports demonstrate that the activation and interaction of the protease calpain (CP) and the protein phosphatase calcineurin (CN) are elevated in the late stages of Alzheimer's disease (AD). However, the extent to which CPs and CN interact during earlier stages of disease progression remains unknown. Here, we investigated CP and CN protein levels in cytosolic, nuclear, and membrane fractions prepared from human postmortem hippocampal tissue from aged non-demented subjects, and subjects diagnosed with mild cognitive impairment (MCI). The results revealed a parallel increase in CP I and the 48 kDa CN-Aα (ΔCN-Aα48) proteolytic fragment in cytosolic fractions during MCI. In primary rat hippocampal cultures, CP-dependent proteolysis and activation of CN was stimulated by application of oligomeric Aβ((1-42)) peptides. Deleterious effects of Aβ on neuronal morphology were reduced by blockade of either CP or CN. NMDA-type glutamate receptors, which help regulate cognition and neuronal viability, and are modulated by CPs and CN, were also investigated in human hippocampus. Relative to controls, MCI subjects showed significantly greater proteolytic levels of the NR2B subunit. Within subjects, the extent of NR2B proteolysis was strongly correlated with the generation of ΔCN-Aα48 in the cytosol. A similar proteolytic pattern for NR2B was also observed in primary rat hippocampal cultures treated with oligomeric Aβ and prevented by inhibition of CP or CN. Together, the results demonstrate that the activation and interaction of CPs and CN are increased early in cognitive decline associated with AD and may help drive other pathologic processes during disease progression.
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Affiliation(s)
- Hafiz Mohmmad Abdul
- The Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536
| | - Irfan Baig
- The Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536
| | - Harry LeVine
- The Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536
| | - Rodney P Guttmann
- The Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536
- Graduate Center for Gerontology, University of Kentucky, Lexington, KY 40536
| | - Christopher M. Norris
- The Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536
- Department of Molecular and Biomedical Pharmacology, University of Kentucky, Lexington, KY40536
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Owen JB, Sultana R, Aluise CD, Erickson MA, Price TO, Bu G, Banks WA, Butterfield DA. Oxidative modification to LDL receptor-related protein 1 in hippocampus from subjects with Alzheimer disease: implications for Aβ accumulation in AD brain. Free Radic Biol Med 2010; 49:1798-803. [PMID: 20869432 PMCID: PMC2970765 DOI: 10.1016/j.freeradbiomed.2010.09.013] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 09/01/2010] [Accepted: 09/15/2010] [Indexed: 11/25/2022]
Abstract
Alzheimer disease (AD) is a neurodegenerative disorder characterized histopathologically by the presence of senile plaques (SPs), neurofibrillary tangles, and synapse loss. The main component of SPs is amyloid-β peptide (Aβ), which has been associated with increased oxidative stress, leading to oxidative modification of proteins and consequently to neurotoxicity and neurodegeneration. Low-density lipoprotein receptor-related protein 1 (LRP1) is the primary moiety responsible for the efflux of Aβ from the brain to the blood across the blood-brain barrier. Impaired brain-to-blood transport of Aβ by LRP1 has been hypothesized to contribute to increased levels of Aβ in AD brain. The cause of LRP1 dysfunction is unknown, but we have hypothesized that Aβ oxidizes LRP1, thus damaging its own transporter. Consistent with this notion, we report in this study a significant increase in the levels of the lipid peroxidation product 4-hydroxy-2-nonenal bound to transmembrane LRP1 in AD hippocampus. In contrast, the levels of LRP1-resident 3-nitrotyrosine did not show a significant increase in AD hippocampus compared to age-matched controls. Based on this study, we propose that Aβ impairs its own efflux from the brain by oxidation of its transporter LRP1, leading to increased Aβ deposition in brain, thereby contributing to subsequent cognitive impairment in AD.
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Affiliation(s)
- Joshua B. Owen
- Department of Chemistry, University of Kentucky, Lexington KY 40506-0055
- Center of Membrane Sciences, University of Kentucky, Lexington, KY 40506-0059, USA
| | - Rukhsana Sultana
- Department of Chemistry, University of Kentucky, Lexington KY 40506-0055
- Center of Membrane Sciences, University of Kentucky, Lexington, KY 40506-0059, USA
| | - Christopher D. Aluise
- Department of Chemistry, University of Kentucky, Lexington KY 40506-0055
- Center of Membrane Sciences, University of Kentucky, Lexington, KY 40506-0059, USA
| | - Michelle A. Erickson
- Departments of Internal Medicine, Geriatric Division and Pharmacological and Physiological Science, St. Louis University, St. Louis, MO 63104, USA
| | - Tulin O. Price
- Departments of Internal Medicine, Geriatric Division and Pharmacological and Physiological Science, St. Louis University, St. Louis, MO 63104, USA
| | - Guojun Bu
- Departments of Pediatrics and of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - William A. Banks
- GRECC- VA Puget Sound Health Care System, Seattle, WA and Division of Gerontology and Geriatric Medicine, Department of Internal Medicine, University of Washington School of Medicine, Seattle, WA 98108, USA
| | - D. Allan Butterfield
- Department of Chemistry, University of Kentucky, Lexington KY 40506-0055
- Center of Membrane Sciences, University of Kentucky, Lexington, KY 40506-0059, USA
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536, USA
- Address correspondence to: Professor D. Allan Butterfield, Dept. of Chemistry, Center of Membrane Sciences, and Sanders-Brown Center on Aging, University of Kentucky, Lexington KY 40506-0055, Tel: 859 257-3184, Fax 859-257-5876,
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49
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Bradley MA, Xiong-Fister S, Markesbery WR, Lovell MA. Elevated 4-hydroxyhexenal in Alzheimer's disease (AD) progression. Neurobiol Aging 2010; 33:1034-44. [PMID: 20965613 DOI: 10.1016/j.neurobiolaging.2010.08.016] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Revised: 08/16/2010] [Accepted: 08/31/2010] [Indexed: 11/29/2022]
Abstract
Multiple studies have demonstrated elevations of α, β-unsaturated aldehydes including 4-hydroxynonenal (HNE) and acrolein, in vulnerable regions of mild cognitive impairment (MCI), preclinical Alzheimer's disease (PCAD), and late stage Alzheimer's disease (LAD) brain. However, there has been limited study of a third member, 4-hydroxyhexenal (HHE), a diffusible lipid peroxidation product of the ω-3 polyunstataturated fatty acids (PUFAs). In the present study levels of extractable and protein-bound HHE were quantified in the hippocampus/parahippocampal gyrus (HPG), superior and middle temporal gyri (SMTG), and cerebellum (CER) of MCI, PCAD, LAD, and normal control (NC) subjects. Levels of extractable and protein-bound HHE were increased in multiple regions in the progression of Alzheimer's disease (AD). Extractable HHE was significantly elevated in the hippocampus/parahippocampal gyrus (HPG) of PCAD and LAD subjects and protein-bound HHE was significantly higher in MCI, PCAD, and LAD HPG. A time- and concentration-dependent decrease in survival and a concentration-dependent decrease in glucose uptake were observed in primary cortical cultures treated with HHE. Together these data support a role for lipid peroxidation in the progression of Alzheimer's disease.
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Affiliation(s)
- Melissa A Bradley
- Department of Chemistry, University of Kentucky, Lexington, KY 40536, USA
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50
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Chouliaras L, Sierksma ASR, Kenis G, Prickaerts J, Lemmens MAM, Brasnjevic I, van Donkelaar EL, Martinez-Martinez P, Losen M, De Baets MH, Kholod N, van Leeuwen F, Hof PR, van Os J, Steinbusch HWM, van den Hove DLA, Rutten BPF. Gene-environment interaction research and transgenic mouse models of Alzheimer's disease. Int J Alzheimers Dis 2010; 2010. [PMID: 20953364 PMCID: PMC2952897 DOI: 10.4061/2010/859101] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2010] [Accepted: 07/31/2010] [Indexed: 01/08/2023] Open
Abstract
The etiology of the sporadic form of Alzheimer's disease (AD) remains largely unknown. Recent evidence has suggested that gene-environment interactions (GxE) may play a crucial role in its development and progression. Whereas various susceptibility loci have been identified, like the apolipoprotein E4 allele, these cannot fully explain the increasing prevalence of AD observed with aging. In addition to such genetic risk factors, various environmental factors have been proposed to alter the risk of developing AD as well as to affect the rate of cognitive decline in AD patients. Nevertheless, aside from the independent effects of genetic and environmental risk factors, their synergistic participation in increasing the risk of developing AD has been sparsely investigated, even though evidence points towards such a direction. Advances in the genetic manipulation of mice, modeling various aspects of the AD pathology, have provided an excellent tool to dissect the effects of genes, environment, and their interactions. In this paper we present several environmental factors implicated in the etiology of AD that have been tested in transgenic animal models of the disease. The focus lies on the concept of GxE and its importance in a multifactorial disease like AD. Additionally, possible mediating mechanisms and future challenges are discussed.
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Affiliation(s)
- L Chouliaras
- School for Mental Health and Neuroscience (MHeNS), Faculty of Health, Medicine and Life Sciences, European Graduate School of Neuroscience (EURON), Maastricht University Medical Centre, P.O. Box 616, 6200 MD Maastricht, The Netherlands
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