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Wei YC, Kung YC, Lin CP, Chen CK, Lin C, Tseng RY, Chen YL, Huang WY, Chen PY, Chong ST, Shyu YC, Chang WC, Yeh CH. White matter alterations and their associations with biomarkers and behavior in subjective cognitive decline individuals: a fixel-based analysis. BEHAVIORAL AND BRAIN FUNCTIONS : BBF 2024; 20:12. [PMID: 38778325 PMCID: PMC11110460 DOI: 10.1186/s12993-024-00238-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Accepted: 05/04/2024] [Indexed: 05/25/2024]
Abstract
BACKGROUND Subjective cognitive decline (SCD) is an early stage of dementia linked to Alzheimer's disease pathology. White matter changes were found in SCD using diffusion tensor imaging, but there are known limitations in voxel-wise tensor-based methods. Fixel-based analysis (FBA) can help understand changes in white matter fibers and how they relate to neurodegenerative proteins and multidomain behavior data in individuals with SCD. METHODS Healthy adults with normal cognition were recruited in the Northeastern Taiwan Community Medicine Research Cohort in 2018-2022 and divided into SCD and normal control (NC). Participants underwent evaluations to assess cognitive abilities, mental states, physical activity levels, and susceptibility to fatigue. Neurodegenerative proteins were measured using an immunomagnetic reduction technique. Multi-shell diffusion MRI data were collected and analyzed using whole-brain FBA, comparing results between groups and correlating them with multidomain assessments. RESULTS The final enrollment included 33 SCD and 46 NC participants, with no significant differences in age, sex, or education between the groups. SCD had a greater fiber-bundle cross-section than NC (pFWE < 0.05) at bilateral frontal superior longitudinal fasciculus II (SLFII). These white matter changes correlate negatively with plasma Aβ42 level (r = -0.38, p = 0.01) and positively with the AD8 score for subjective cognitive complaints (r = 0.42, p = 0.004) and the Hamilton Anxiety Rating Scale score for the degree of anxiety (Ham-A, r = 0.35, p = 0.019). The dimensional analysis of FBA metrics and blood biomarkers found positive correlations of plasma neurofilament light chain with fiber density at the splenium of corpus callosum (pFWE < 0.05) and with fiber-bundle cross-section at the right thalamus (pFWE < 0.05). Further examination of how SCD grouping interacts between the correlations of FBA metrics and multidomain assessments showed interactions between the fiber density at the corpus callosum with letter-number sequencing cognitive score (pFWE < 0.01) and with fatigue to leisure activities (pFWE < 0.05). CONCLUSION Based on FBA, our investigation suggests white matter structural alterations in SCD. The enlargement of SLFII's fiber cross-section is linked to plasma Aβ42 and neuropsychiatric symptoms, which suggests potential early axonal dystrophy associated with Alzheimer's pathology in SCD. The splenium of the corpus callosum is also a critical region of axonal degeneration and cognitive alteration for SCD.
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Affiliation(s)
- Yi-Chia Wei
- Department of Neurology, Chang Gung Memorial Hospital, Keelung, 204, Taiwan
- Community Medicine Research Center, Chang Gung Memorial Hospital, Keelung, 204, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, 333, Taiwan
- Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei, 112, Taiwan
| | - Yi-Chia Kung
- Department of Radiology, Tri-Service General Hospital, National Defense Medical Center, Taipei, 114, Taiwan
| | - Ching-Po Lin
- Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei, 112, Taiwan
- Department of Education and Research, Taipei City Hospital, Taipei, Taiwan
| | - Chih-Ken Chen
- Community Medicine Research Center, Chang Gung Memorial Hospital, Keelung, 204, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, 333, Taiwan
- Department of Psychiatry, Chang Gung Memorial Hospital, Keelung, 204, Taiwan
| | - Chemin Lin
- Community Medicine Research Center, Chang Gung Memorial Hospital, Keelung, 204, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, 333, Taiwan
- Department of Psychiatry, Chang Gung Memorial Hospital, Keelung, 204, Taiwan
| | - Rung-Yu Tseng
- Department of Medical Imaging and Radiological Sciences, Chang Gung University, Taoyuan, 333, Taiwan
| | - Yao-Liang Chen
- Department of Medical Imaging and Radiological Sciences, Chang Gung University, Taoyuan, 333, Taiwan
- Department of Radiology, Chang Gung Memorial Hospital, Keelung, 204, Taiwan
| | - Wen-Yi Huang
- Department of Neurology, Chang Gung Memorial Hospital, Keelung, 204, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, 333, Taiwan
| | - Pin-Yuan Chen
- Community Medicine Research Center, Chang Gung Memorial Hospital, Keelung, 204, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, 333, Taiwan
- Department of Neurosurgery, Chang Gung Memorial Hospital, Keelung, 204, Taiwan
| | - Shin-Tai Chong
- Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei, 112, Taiwan
| | - Yu-Chiau Shyu
- Community Medicine Research Center, Chang Gung Memorial Hospital, Keelung, 204, Taiwan
- Department of Nursing, Chang Gung University of Science and Technology, Taoyuan, 333, Taiwan
| | - Wei-Chou Chang
- Department of Radiology, Tri-Service General Hospital, National Defense Medical Center, Taipei, 114, Taiwan
| | - Chun-Hung Yeh
- Department of Medical Imaging and Radiological Sciences, Chang Gung University, Taoyuan, 333, Taiwan.
- Department of Psychiatry, Chang Gung Memorial Hospital at Linkou, Taoyuan, 333, Taiwan.
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Yang S, Niou ZX, Enriquez A, LaMar J, Huang JY, Ling K, Jafar-Nejad P, Gilley J, Coleman MP, Tennessen JM, Rangaraju V, Lu HC. NMNAT2 supports vesicular glycolysis via NAD homeostasis to fuel fast axonal transport. Mol Neurodegener 2024; 19:13. [PMID: 38282024 PMCID: PMC10823734 DOI: 10.1186/s13024-023-00690-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 11/28/2023] [Indexed: 01/30/2024] Open
Abstract
BACKGROUND Bioenergetic maladaptations and axonopathy are often found in the early stages of neurodegeneration. Nicotinamide adenine dinucleotide (NAD), an essential cofactor for energy metabolism, is mainly synthesized by Nicotinamide mononucleotide adenylyl transferase 2 (NMNAT2) in CNS neurons. NMNAT2 mRNA levels are reduced in the brains of Alzheimer's, Parkinson's, and Huntington's disease. Here we addressed whether NMNAT2 is required for axonal health of cortical glutamatergic neurons, whose long-projecting axons are often vulnerable in neurodegenerative conditions. We also tested if NMNAT2 maintains axonal health by ensuring axonal ATP levels for axonal transport, critical for axonal function. METHODS We generated mouse and cultured neuron models to determine the impact of NMNAT2 loss from cortical glutamatergic neurons on axonal transport, energetic metabolism, and morphological integrity. In addition, we determined if exogenous NAD supplementation or inhibiting a NAD hydrolase, sterile alpha and TIR motif-containing protein 1 (SARM1), prevented axonal deficits caused by NMNAT2 loss. This study used a combination of techniques, including genetics, molecular biology, immunohistochemistry, biochemistry, fluorescent time-lapse imaging, live imaging with optical sensors, and anti-sense oligos. RESULTS We provide in vivo evidence that NMNAT2 in glutamatergic neurons is required for axonal survival. Using in vivo and in vitro studies, we demonstrate that NMNAT2 maintains the NAD-redox potential to provide "on-board" ATP via glycolysis to vesicular cargos in distal axons. Exogenous NAD+ supplementation to NMNAT2 KO neurons restores glycolysis and resumes fast axonal transport. Finally, we demonstrate both in vitro and in vivo that reducing the activity of SARM1, an NAD degradation enzyme, can reduce axonal transport deficits and suppress axon degeneration in NMNAT2 KO neurons. CONCLUSION NMNAT2 ensures axonal health by maintaining NAD redox potential in distal axons to ensure efficient vesicular glycolysis required for fast axonal transport.
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Affiliation(s)
- Sen Yang
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
| | - Zhen-Xian Niou
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA
| | - Andrea Enriquez
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA
| | - Jacob LaMar
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
- Present address: Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, 33458, USA
| | - Jui-Yen Huang
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
| | - Karen Ling
- Neuroscience Drug Discovery, Ionis Pharmaceuticals, Inc., 2855, Gazelle Court, Carlsbad, CA, 92010, USA
| | - Paymaan Jafar-Nejad
- Neuroscience Drug Discovery, Ionis Pharmaceuticals, Inc., 2855, Gazelle Court, Carlsbad, CA, 92010, USA
| | - Jonathan Gilley
- Department of Clinical Neuroscience, Cambridge University, Cambridge, UK
| | - Michael P Coleman
- Department of Clinical Neuroscience, Cambridge University, Cambridge, UK
| | - Jason M Tennessen
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA
| | - Vidhya Rangaraju
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
| | - Hui-Chen Lu
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA.
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA.
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA.
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Yang S, Niou ZX, Enriquez A, LaMar J, Huang JY, Ling K, Jafar-Nejad P, Gilley J, Coleman MP, Tennessen JM, Rangaraju V, Lu HC. NMNAT2 supports vesicular glycolysis via NAD homeostasis to fuel fast axonal transport. RESEARCH SQUARE 2023:rs.3.rs-2859584. [PMID: 37292715 PMCID: PMC10246254 DOI: 10.21203/rs.3.rs-2859584/v1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Background Bioenergetic maladaptations and axonopathy are often found in the early stages of neurodegeneration. Nicotinamide adenine dinucleotide (NAD), an essential cofactor for energy metabolism, is mainly synthesized by Nicotinamide mononucleotide adenylyl transferase 2 (NMNAT2) in CNS neurons. NMNAT2 mRNA levels are reduced in the brains of Alzheimer's, Parkinson's, and Huntington's disease. Here we addressed whether NMNAT2 is required for axonal health of cortical glutamatergic neurons, whose long-projecting axons are often vulnerable in neurodegenerative conditions. We also tested if NMNAT2 maintains axonal health by ensuring axonal ATP levels for axonal transport, critical for axonal function. Methods We generated mouse and cultured neuron models to determine the impact of NMNAT2 loss from cortical glutamatergic neurons on axonal transport, energetic metabolism, and morphological integrity. In addition, we determined if exogenous NAD supplementation or inhibiting a NAD hydrolase, sterile alpha and TIR motif-containing protein 1 (SARM1), prevented axonal deficits caused by NMNAT2 loss. This study used a combination of genetics, molecular biology, immunohistochemistry, biochemistry, fluorescent time-lapse imaging, live imaging with optical sensors, and anti-sense oligos. Results We provide in vivo evidence that NMNAT2 in glutamatergic neurons is required for axonal survival. Using in vivo and in vitro studies, we demonstrate that NMNAT2 maintains the NAD-redox potential to provide "on-board" ATP via glycolysis to vesicular cargos in distal axons. Exogenous NAD+ supplementation to NMNAT2 KO neurons restores glycolysis and resumes fast axonal transport. Finally, we demonstrate both in vitro and in vivo that reducing the activity of SARM1, an NAD degradation enzyme, can reduce axonal transport deficits and suppress axon degeneration in NMNAT2 KO neurons. Conclusion NMNAT2 ensures axonal health by maintaining NAD redox potential in distal axons to ensure efficient vesicular glycolysis required for fast axonal transport.
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Nishioka C, Liang HF, Ong S, Sun SW. Axonal transport impairment and its relationship with diffusion tensor imaging metrics of a murine model of p301L tau induced tauopathy. Neuroscience 2022; 498:144-154. [PMID: 35753531 DOI: 10.1016/j.neuroscience.2022.06.025] [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: 05/05/2022] [Accepted: 06/15/2022] [Indexed: 11/15/2022]
Abstract
Diffusion Tensor Imaging (DTI) and Manganese Enhanced MRI (MEMRI) are noninvasive tools to characterize neural fiber microstructure and axonal transport. A combination of both may provide novel insights into the progress of neurodegeneration. To investigate the relationship of DTI and MEMRI in white matter of tauopathy, twelve optic nerves of 11-month-old p301L tau mice were imaged and finished with postmortem immunohistochemistry. MEMRI was used to quantify Mn2+ accumulation rates in the optic nerve (ON, termed ONAR) and the Superior Colliculus (SC, termed SCAR), the primary terminal site of ON in mice. We found that both ONAR and SCAR revealed a significant linear correlation with mean diffusion (mD) and radial diffusion (rD) but not with other DTI quantities. Immunohistochemistry findings showed that ONAR, mD, and rD are significantly correlated with the myelin content (Myelin Basic Protein, p < 0.05) but not with the axonal density (SMI-31), tubulin density, or tau aggregates (AT8 staining). In summary, slower axonal transport appeared to have less myelinated axons and thinner remaining axons, associated with reduced rD and mD of in vivo DTI. A combination of in vivo MEMRI and DTI can provide critical information to delineate the progress of white matter deficits in neurodegenerative diseases.
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Affiliation(s)
- Christopher Nishioka
- Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, CA, United States; Neuroscience Graduate Program, University of California, Riverside, CA, United States
| | - Hsiao-Fang Liang
- Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, CA, United States
| | - Stephen Ong
- Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, CA, United States; Robert Wood Johnson Barnabas Health (RWJBH) and Rutgers University, United States
| | - Shu-Wei Sun
- Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, CA, United States; Neuroscience Graduate Program, University of California, Riverside, CA, United States.
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Tian Y, Gao G, Dai J. Severe tauopathy and axonopathy in the medulla oblongata in Alzheimer's disease implicate the changes in autonomic nervous function. J Chem Neuroanat 2022; 123:102105. [PMID: 35568249 DOI: 10.1016/j.jchemneu.2022.102105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 05/06/2022] [Accepted: 05/07/2022] [Indexed: 11/17/2022]
Abstract
The autonomic dysfunctions in Alzheimer's disease (AD) have been identified from many clinical studies, however, there is still a lack of evidence directly verifying the structural abnormalities of the autonomic nervous system in AD. Human medulla oblongatas from four AD patients or five non-AD subjects were obtained and observed by using immunohistochemical staining of hyperphosphorylated tau and Aβ amyloid, and post-mortem tracing techniques. We found distinct axonal and somatic immunoreactivities for the tau markers AT8 and Tau-5 in the different areas of the medulla oblongata in AD patients, which was particularly obvious in the dorsal nucleus of the vagus nerve, the nucleus of the solitary tract and the reticular nucleus. The swollen axons, which are a typical feature of axonopathy, were not only identified in the axons with immunohistochemical labeling of AT8 and Tau-5 in the different nuclei of the medulla oblongata, but also in the tracer-labeled afferent and efferent fibres of the vagus nerve in AD patients. Such changes in tauopathy and axonopathy were only occasionally found in the non-AD aged subjects. Interestingly, we did not observe any intra- or extracellular Aβ deposits in the medulla oblongatas of the AD patients or of the non-AD subjects. These results in small samples suggest that occurrence of tauopathy and axonopathy in the parasympathetic nuclei of the medulla oblongata in AD patients may implicate the change of autonomic nervous function.
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Affiliation(s)
- Yi Tian
- Wuhan Institute for Neuroscience and Neuroengineering, South-Central Minzu University, Wuhan, Hubei, China; The College of Life Sciences, South-Central Minzu University, Wuhan, Hubei, China
| | - Ge Gao
- Tongji University School of Medicine, Shanghai, China
| | - Jiapei Dai
- Wuhan Institute for Neuroscience and Neuroengineering, South-Central Minzu University, Wuhan, Hubei, China; The College of Life Sciences, South-Central Minzu University, Wuhan, Hubei, China.
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Pathophysiology of neurodegenerative diseases: An interplay among axonal transport failure, oxidative stress, and inflammation? Semin Immunol 2022; 59:101628. [PMID: 35779975 PMCID: PMC9807734 DOI: 10.1016/j.smim.2022.101628] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 04/09/2022] [Accepted: 06/13/2022] [Indexed: 01/15/2023]
Abstract
Neurodegenerative diseases (NDs) are heterogeneous neurological disorders characterized by a progressive loss of selected neuronal populations. A significant risk factor for most NDs is aging. Considering the constant increase in life expectancy, NDs represent a global public health burden. Axonal transport (AT) is a central cellular process underlying the generation and maintenance of neuronal architecture and connectivity. Deficits in AT appear to be a common thread for most, if not all, NDs. Neuroinflammation has been notoriously difficult to define in relation to NDs. Inflammation is a complex multifactorial process in the CNS, which varies depending on the disease stage. Several lines of evidence suggest that AT defect, axonopathy and neuroinflammation are tightly interlaced. However, whether these impairments play a causative role in NDs or are merely a downstream effect of neuronal degeneration remains unsettled. We still lack reliable information on the temporal relationship between these pathogenic mechanisms, although several findings suggest that they may occur early during ND pathophysiology. This article will review the latest evidence emerging on whether the interplay between AT perturbations and some aspects of CNS inflammation can participate in ND etiology, analyze their potential as therapeutic targets, and the urge to identify early surrogate biomarkers.
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Lomoio S, Willen R, Kim W, Ho KZ, Robinson EK, Prokopenko D, Kennedy ME, Tanzi RE, Tesco G. Gga3 deletion and a GGA3 rare variant associated with late onset Alzheimer's disease trigger BACE1 accumulation in axonal swellings. Sci Transl Med 2021; 12:12/570/eaba1871. [PMID: 33208500 DOI: 10.1126/scitranslmed.aba1871] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 05/18/2020] [Accepted: 08/03/2020] [Indexed: 12/13/2022]
Abstract
Axonal dystrophy, indicative of perturbed axonal transport, occurs early during Alzheimer's disease (AD) pathogenesis. Little is known about the mechanisms underlying this initial sign of the pathology. This study proves that Golgi-localized γ-ear-containing ARF binding protein 3 (GGA3) loss of function, due to Gga3 genetic deletion or a GGA3 rare variant that cosegregates with late-onset AD, disrupts the axonal trafficking of the β-site APP-cleaving enzyme 1 (BACE1) resulting in its accumulation in axonal swellings in cultured neurons and in vivo. We show that BACE pharmacological inhibition ameliorates BACE1 axonal trafficking and diminishes axonal dystrophies in Gga3 null neurons in vitro and in vivo. These data indicate that axonal accumulation of BACE1 engendered by GGA3 loss of function results in local toxicity leading to axonopathy. Gga3 deletion exacerbates axonal dystrophies in a mouse model of AD before β-amyloid (Aβ) deposition. Our study strongly supports a role for GGA3 in AD pathogenesis, where GGA3 loss of function triggers BACE1 axonal accumulation independently of extracellular Aβ, and initiates a cascade of events leading to the axonal damage distinctive of the early stage of AD.
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Affiliation(s)
- Selene Lomoio
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Rachel Willen
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA
| | - WonHee Kim
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Kevin Z Ho
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Edward K Robinson
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Dmitry Prokopenko
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | | | - Rudolph E Tanzi
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Giuseppina Tesco
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA.
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Zhang J, Wu N, Wang S, Yao Z, Xiao F, Lu J, Chen B. Neuronal loss and microgliosis are restricted to the core of Aβ deposits in mouse models of Alzheimer's disease. Aging Cell 2021; 20:e13380. [PMID: 34080759 PMCID: PMC8208784 DOI: 10.1111/acel.13380] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 04/11/2021] [Accepted: 04/26/2021] [Indexed: 12/24/2022] Open
Abstract
Amyloid‐β (Aβ) deposits, pathologic tau, and neurodegeneration are major pathological hallmarks of Alzheimer's disease (AD). The relationship between neuronal loss and Aβ deposits is one of the fundamental questions in the pathogenesis of AD. However, this relationship is controversial. One main reason for the conflicting results may be the confounding effects of pathologic tau, which often coexists with Aβ deposits in the brains of AD patients. To clarify the relationship between neuronal loss and Aβ deposits, mouse models of AD, which develop abundant Aβ deposits in the aged brain without pathologic tau, were used to examine the co‐localization of NeuN‐positive neurons, NF‐H‐positive axons, MBP‐positive myelin sheaths, and Aβ deposits. Neuronal loss, as measured by decreased staining of the neuronal cell body, axon, and myelin sheath, as well as the IBA‐1‐positive microglia, was significantly increased in the core area of cerebral Aβ deposits, but not in adjacent areas. Furthermore, neuronal loss in the core area of cerebral Aβ deposits was correlated with Aβ deposit size. These results clearly indicate that neuronal loss is restricted to the core of Aβ deposits, and this restricted loss probably occurs because the Aβ deposit attracts microglia, which cluster in the core area where Aβ toxicity and neuroinflammation toxicity are restrained. These findings may contribute to our understanding of the relationship between neuronal loss and Aβ deposits in the absence of pathologic tau.
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Affiliation(s)
- Jing Zhang
- School of Basic Medical Sciences Beijing Key Laboratory of Neural Regeneration and RepairCapital Medical University Beijing China
- Laboratory Animal Resource Center Capital Medical University Beijing China
| | - Na Wu
- Laboratory Animal Resource Center Capital Medical University Beijing China
| | - Shubo Wang
- Laboratory Animal Resource Center Capital Medical University Beijing China
| | - Zitong Yao
- Laboratory Animal Resource Center Capital Medical University Beijing China
| | - Fuchuan Xiao
- School of Basic Medical Sciences Beijing Key Laboratory of Neural Regeneration and RepairCapital Medical University Beijing China
| | - Jing Lu
- School of Basic Medical Sciences Beijing Key Laboratory of Neural Regeneration and RepairCapital Medical University Beijing China
- Laboratory Animal Resource Center Capital Medical University Beijing China
| | - Baian Chen
- School of Basic Medical Sciences Beijing Key Laboratory of Neural Regeneration and RepairCapital Medical University Beijing China
- Laboratory Animal Resource Center Capital Medical University Beijing China
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Ye JY, Hao Q, Zong Y, Shen Y, Zhang Z, Ma C. Sophocarpine Attenuates Cognitive Impairment and Promotes Neurogenesis in a Mouse Model of Alzheimer's Disease. Neuroimmunomodulation 2021; 28:166-177. [PMID: 34320497 DOI: 10.1159/000508655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 05/08/2020] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Alzheimer's disease (AD), which is characterized by abnormal deposition of amyloid-β (Aβ) plaques and impaired neurogenesis and cognition, still lacks an optimally effective therapeutic agent for its management, and mounting evidence has shown that inflammatory processes are implicated in AD. Sophocarpine has been reported to exert inflammation-regulating effects in various diseases. However, whether sophocarpine can exert anti-neuroinflammatory and neuroprotective effects in AD remains unclear. This study investigated whether sophocarpine could ameliorate the pathological features and potential mechanisms in a mouse AD model. METHODS APP/PS1 mice were treated with sophocarpine for 8 weeks. We quantified the effects of sophocarpine treatment on cognitive performance using a behavioral test. Brain Aβ deposits and neurogenesis were evaluated using immunofluorescence staining. We also assessed the morphology and inflammatory changes induced by sophocarpine administration and its expression in the hippocampus. RESULTS Administration of sophocarpine significantly alleviated cognitive impairment and reduced neural loss. APP/PS1 mice treated with sophocarpine showed reduced Aβ plaque deposits and enhanced neurogenesis. Sophocarpine markedly decreased the expression of inflammation markers and inhibited microglial activation. CONCLUSIONS Sophocarpine could potentially alleviate cognitive impairment and brain damage in APP/PS1 mice with its neuroprotective effects via modulation of the inflammatory pathway.
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Affiliation(s)
- Jian-Ya Ye
- Department of Nursing, Hebei University of Chinese Medicine, Shijiazhang, China
| | - Qingmao Hao
- Department of Nursing, Hebei University of Chinese Medicine, Shijiazhang, China
| | - Yijun Zong
- Department of Nursing, Hebei University of Chinese Medicine, Shijiazhang, China
| | - Yongqing Shen
- Department of Nursing, Hebei University of Chinese Medicine, Shijiazhang, China
| | - Zhiqin Zhang
- Department of Nursing, Hebei University of Chinese Medicine, Shijiazhang, China
| | - Changsheng Ma
- Neurobiology Laboratory, Institute of Basic Medicine, Hebei Medical University, Shijiazhang, China
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Zhou L, Huang JY, Zhang D, Zhao YL. Cognitive improvements and reduction in amyloid plaque deposition by saikosaponin D treatment in a murine model of Alzheimer's disease. Exp Ther Med 2020; 20:1082-1090. [PMID: 32742347 PMCID: PMC7388258 DOI: 10.3892/etm.2020.8760] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 04/17/2020] [Indexed: 12/18/2022] Open
Abstract
Alzheimer's disease (AD), is a severe neurodegenerative disease that currently lacks an optimally effective therapeutic agent for its management. Saikosaponin D (SSD) is a component extracted from the herb Bupleurum falcatum that is commonly used in Chinese medicine. Although SSD has been reported to exert neuroprotective effects, its pharmacological role in AD has not been previously elucidated. Therefore, the aim of the present study was to investigate whether SSD treatment improves the cognitive function and pathological features of 3xTg mice, a triple-transgenic mouse model of AD that displays classical pathological features of AD. The effects of SSD treatment on the behavioral, histological and physiological features of the animal were quantified. Results from the behavioral experiments on the SSD-treated 3xTg mice identified a significant reduction in memory impairment. In addition, histological staining results indicated that SSD application could preserve the morphology of neurons, reduce apoptosis and significantly inhibit amyloid-β deposition in the hippocampus of 3xTg mice. SSD treatment also decelerated the activation of microglia and astrocytes in the hippocampus of 3xTg mice, possibly via the inhibition of the NF-κB signal transduction pathway. Therefore, the present study demonstrated the protective effects of SSD against progressive neurodegeneration and identified the potential underlying pharmacological mechanism. It was speculated that SSD may serve as a possible therapeutic agent in AD treatment in the future.
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Affiliation(s)
- Li Zhou
- Health Management Center, Wuhan Hospital of Traditional Chinese Medicine, Wuhan, Hubei 430014, P.R. China
| | - Jin-Yuan Huang
- Health Management Center, Wuhan Hospital of Traditional Chinese Medicine, Wuhan, Hubei 430014, P.R. China
| | - Di Zhang
- Health Management Center, Wuhan Hospital of Traditional Chinese Medicine, Wuhan, Hubei 430014, P.R. China
| | - Ya-Liang Zhao
- Health Management Center, Wuhan Hospital of Traditional Chinese Medicine, Wuhan, Hubei 430014, P.R. China
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Gao G, He J, Luo Y, Sun Y, Zhou Y, Zhang J, Xing Y, Dai J. Axonopathy Likely Initiates Neuropathological Processes Via a Mechanism of Axonal Leakage in Alzheimer's Mouse Models. Curr Mol Med 2020; 19:183-195. [PMID: 30961496 DOI: 10.2174/1566524019666190405174908] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 03/14/2019] [Accepted: 03/15/2019] [Indexed: 12/31/2022]
Abstract
BACKGROUND The formation of hyperphosphorylated tau and the production of β-amyloid are thought to be critical steps contributing to the pathological mechanisms in Alzheimer's disease (AD). However, there has been a long-lasting debate over their importance in the onset of AD. Recent studies have demonstrated that axonopathy is considered as an early neuropathological change of AD. However, the exact relationship between the development of axonopathy and the classic neuropathological changes such as senile plaques (SPs) and neurofibrillary tangles (NFTs) is unclear. OBJECTIVE The aim of this study was to investigate whether the formation of SPs and NFTs is associated with the development of axonal leakage. METHOD AND RESULTS Here we show that the formation and development of axonal leakage - a novel axonopathy is an age-dependent process, accompanied by swellings of axons and varicosities and associated with chronic oxidative stress induced by thiamine deficient (TD) diet in Kunming mice. In an APP/PS1 transgenic mouse model of AD, axonal leakage appears at 3 months, becomes more obvious at 6 months and severe, beyond 1 year. We also show that slight axonal leakage is related to the formation of hyperphosphorylated tau, but not plaques, and that only severe axonal leakage accompanied by the extensive swollen axons and varicosities, and overproduction of β-amyloid leads to the formation of SPs and hyperphosphorylated tau. CONCLUSION These data provide an explanation of the common origin and development of SPs and NFTs, and suggest that axonal leakage might be a key event in the development of the neuropathological processes in AD.
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Affiliation(s)
- Ge Gao
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan, China
| | - Jing He
- Wuhan Institute for Neuroscience and Neuroengineering, South-Central University for Nationalities, Wuhan, Hubei, China.,Clinical Laboratory of the Second Affiliated Hospital, Hunan University of Chinese Medicine, Changsha, China
| | - Yi Luo
- Wuhan Institute for Neuroscience and Neuroengineering, South-Central University for Nationalities, Wuhan, Hubei, China.,Clinical Laboratory of Zhongnan Hospital, Wuhan University, Wuhan, Hubei, China
| | - Yan Sun
- Wuhan Institute for Neuroscience and Neuroengineering, South-Central University for Nationalities, Wuhan, Hubei, China.,The College of Life Sciences, South-Central University for Nationalities, Wuhan, Hubei, China
| | - Yanping Zhou
- Wuhan Institute for Neuroscience and Neuroengineering, South-Central University for Nationalities, Wuhan, Hubei, China.,Department of Pathophysiology, Guangxi University of Chinese Medicine, Nanning, Guangxi, China
| | - Junxia Zhang
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan, China.,Department of Anatomy, Histology and Embryology, Henan University of Chinese Medicine, Zhengzhou, Henan, China
| | - Ying Xing
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan, China
| | - Jiapei Dai
- Wuhan Institute for Neuroscience and Neuroengineering, South-Central University for Nationalities, Wuhan, Hubei, China.,The College of Life Sciences, South-Central University for Nationalities, Wuhan, Hubei, China
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12
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Tseng JH, Xie L, Song S, Xie Y, Allen L, Ajit D, Hong JS, Chen X, Meeker RB, Cohen TJ. The Deacetylase HDAC6 Mediates Endogenous Neuritic Tau Pathology. Cell Rep 2018; 20:2169-2183. [PMID: 28854366 DOI: 10.1016/j.celrep.2017.07.082] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 05/09/2017] [Accepted: 07/31/2017] [Indexed: 01/22/2023] Open
Abstract
The initiating events that promote tau mislocalization and pathology in Alzheimer's disease (AD) are not well defined, partly because of the lack of endogenous models that recapitulate tau dysfunction. We exposed wild-type neurons to a neuroinflammatory trigger and examined the effect on endogenous tau. We found that tau re-localized and accumulated within pathological neuritic foci, or beads, comprised of mostly hypo-phosphorylated, acetylated, and oligomeric tau. These structures were detected in aged wild-type mice and were enhanced in response to neuroinflammation in vivo, highlighting a previously undescribed endogenous age-related tau pathology. Strikingly, deletion or inhibition of the cytoplasmic shuttling factor HDAC6 suppressed neuritic tau bead formation in neurons and mice. Using mass spectrometry-based profiling, we identified a single neuroinflammatory factor, the metalloproteinase MMP-9, as a mediator of neuritic tau beading. Thus, our study uncovers a link between neuroinflammation and neuritic tau beading as a potential early-stage pathogenic mechanism in AD.
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Affiliation(s)
- Jui-Heng Tseng
- Department of Neurology, University of North Carolina, Chapel Hill, NC 27599, USA; UNC Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Ling Xie
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Sheng Song
- Neuropharmacology Section, Neurobiology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Youmei Xie
- Department of Neurology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Lauren Allen
- Department of Neurology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Deepa Ajit
- Department of Neurology, University of North Carolina, Chapel Hill, NC 27599, USA; UNC Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Jau-Shyong Hong
- Neuropharmacology Section, Neurobiology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Xian Chen
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Rick B Meeker
- Department of Neurology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Todd J Cohen
- Department of Neurology, University of North Carolina, Chapel Hill, NC 27599, USA; UNC Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, USA.
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13
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Yuan Q, Yang J, Wu W, Lin ZX. Motor deficits are independent of axonopathy in an Alzheimer's disease mouse model of TgCRND8 mice. Oncotarget 2017; 8:97900-97912. [PMID: 29228660 PMCID: PMC5716700 DOI: 10.18632/oncotarget.18429] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 05/08/2017] [Indexed: 12/21/2022] Open
Abstract
There have been an increasing number of reports of non-cognitive symptoms in Alzheimer's disease (AD). Some symptoms are associated with the loss of motor functions, e.g. gait disturbances, disturbed activity level and balance. Consistent with clinical findings, several AD mouse models harboring amyloid pathology develop motor impairment. Although the factors that contribute to the motor deficits have not yet been determined, it has been suggested that axonopathy is one of the key factors that may contribute to this particular feature of the disease. Our previous study found that TgCRND8 mice exhibited profound motor deficits as early as 3 months old. In this study, we explored the possible factors that may be related to motor deficits in TgCRND8 mice. Results from silver, neurofilament and amyloid precursor protein (APP) staining revealed no axonopathy occurred in the brain and spinal cord of TgCRND8 mice at the age of 3 months. Anterograde labeling of corticospinal tract of spinal cord and electronic microscopy (EM) analysis showed that no axonopathy occurred in TgCRND8 mice at the age of 3 months. According to these results, it could be concluded that no axonal alterations were evident in the TgCRND8 mice when motor deficits was overt. Thus, axonopathy may play a less prominent role in motor deficits in AD. These results suggest that mechanisms by which motor function undergo impairment in AD need to be further studied.
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Affiliation(s)
- Qiuju Yuan
- School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
- Brain Research Centre, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Jian Yang
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Wutian Wu
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
- State Key Laboratory of Brain and Cognitive Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
- Research Center of Reproduction, Development and Growth, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
- GHM Institute of CNS regeneration, Jinan University, Guangzhou, China
| | - Zhi-Xiu Lin
- School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
- Brain Research Centre, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
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14
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Salvadores N, Sanhueza M, Manque P, Court FA. Axonal Degeneration during Aging and Its Functional Role in Neurodegenerative Disorders. Front Neurosci 2017; 11:451. [PMID: 28928628 PMCID: PMC5591337 DOI: 10.3389/fnins.2017.00451] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 07/25/2017] [Indexed: 12/11/2022] Open
Abstract
Aging constitutes the main risk factor for the development of neurodegenerative diseases. This represents a major health issue worldwide that is only expected to escalate due to the ever-increasing life expectancy of the population. Interestingly, axonal degeneration, which occurs at early stages of neurodegenerative disorders (ND) such as Alzheimer's disease, Amyotrophic lateral sclerosis, and Parkinson's disease, also takes place as a consequence of normal aging. Moreover, the alteration of several cellular processes such as proteostasis, response to cellular stress and mitochondrial homeostasis, which have been described to occur in the aging brain, can also contribute to axonal pathology. Compelling evidence indicate that the degeneration of axons precedes clinical symptoms in NDs and occurs before cell body loss, constituting an early event in the pathological process and providing a potential therapeutic target to treat neurodegeneration before neuronal cell death. Although, normal aging and the development of neurodegeneration are two processes that are closely linked, the molecular basis of the switch that triggers the transition from healthy aging to neurodegeneration remains unrevealed. In this review we discuss the potential role of axonal degeneration in this transition and provide a detailed overview of the literature and current advances in the molecular understanding of the cellular changes that occur during aging that promote axonal degeneration and then discuss this in the context of ND.
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Affiliation(s)
- Natalia Salvadores
- Center for Integrative Biology, Faculty of Sciences, Universidad MayorSantiago, Chile.,Fondap Geroscience Center for Brain Health and MetabolismSantiago, Chile
| | - Mario Sanhueza
- Center for Integrative Biology, Faculty of Sciences, Universidad MayorSantiago, Chile.,Fondap Geroscience Center for Brain Health and MetabolismSantiago, Chile
| | - Patricio Manque
- Center for Integrative Biology, Faculty of Sciences, Universidad MayorSantiago, Chile
| | - Felipe A Court
- Center for Integrative Biology, Faculty of Sciences, Universidad MayorSantiago, Chile.,Fondap Geroscience Center for Brain Health and MetabolismSantiago, Chile
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15
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Clinical tests of neurotrophic factors for human neurodegenerative diseases, part 2: Where do we stand and where must we go next? Neurobiol Dis 2017; 97:169-178. [DOI: 10.1016/j.nbd.2016.03.026] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 03/30/2016] [Indexed: 12/13/2022] Open
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16
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Teixeira CVL, Rezende TJR, Weiler M, Nogueira MH, Campos BM, Pegoraro LFL, Vicentini JE, Scriptore G, Cendes F, Balthazar MLF. Relation between aerobic fitness and brain structures in amnestic mild cognitive impairment elderly. AGE (DORDRECHT, NETHERLANDS) 2016; 38:51. [PMID: 27106271 PMCID: PMC5005905 DOI: 10.1007/s11357-016-9912-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 04/05/2016] [Indexed: 06/05/2023]
Abstract
Mild cognitive impairment (aMCI) is a clinical condition, with high risk to develop Alzheimer's disease. Physical exercise may have positive effect on cognition and brain structure in older adults. However, it is still under research whether these influences are true on aMCI subjects with low Ab_42 and high total tau in cerebrospinal fluid (CSF), which is considered a biomarker for AD. Therefore, we aimed to investigate a possible relation between aerobic fitness (AF) and gray matter (GM) volume and AF and white matter (WM) integrity in aMCI with a CSF biomarker. Twenty-two participants with aMCI acquired the images on a 3.0-T MRI. AF was assessed by a graded exercise test on a treadmill. Voxel-based morphometry and tract-based spatial statistic methods were used to analyze the GM volume and WM microstructural integrity, respectively. We correlated AF and GM volume and WM integrity in aMCI (p < 0.05, FWE corrected, cluster with at least five voxels). There was a positive relation between AF and GM volume mostly in frontal superior cortex. In WM integrity, AF was positively correlated with fractional anisotropy and negatively correlated with mean diffusivity and radial diffusivity, all in the same tracts that interconnect frontal, temporal, parietal, and occipital areas (longitudinal fasciculus, fronto-occipital fasciculus, and corpus callosum). These results suggest that aerobic fitness may have a positive influence on protection of brain even in aMCI CSF biomarker, a high-risk population to convert to AD.
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Affiliation(s)
- Camila Vieira Ligo Teixeira
- NeuroImage Laboratory, Department of Neurology, Medical Sciences Faculty, UNICAMP, Rua Vital Brasil, 251 Cidade Universitária Zeferino Vaz, Campinas, SP, CEP-13083-888, Brazil.
| | - Thiago J R Rezende
- Medical Physics Laboratory, Department of Neurology, Medical Sciences Faculty, UNICAMP, Campinas, São Paulo, Brazil
| | - Marina Weiler
- NeuroImage Laboratory, Department of Neurology, Medical Sciences Faculty, UNICAMP, Rua Vital Brasil, 251 Cidade Universitária Zeferino Vaz, Campinas, SP, CEP-13083-888, Brazil
| | - Mateus H Nogueira
- NeuroImage Laboratory, Department of Neurology, Medical Sciences Faculty, UNICAMP, Rua Vital Brasil, 251 Cidade Universitária Zeferino Vaz, Campinas, SP, CEP-13083-888, Brazil
| | - Brunno M Campos
- NeuroImage Laboratory, Department of Neurology, Medical Sciences Faculty, UNICAMP, Rua Vital Brasil, 251 Cidade Universitária Zeferino Vaz, Campinas, SP, CEP-13083-888, Brazil
| | - Luiz F L Pegoraro
- Department of Psychiatry, Medical Sciences Faculty, UNICAMP, Campinas, São Paulo, Brazil
| | - Jessica E Vicentini
- NeuroImage Laboratory, Department of Neurology, Medical Sciences Faculty, UNICAMP, Rua Vital Brasil, 251 Cidade Universitária Zeferino Vaz, Campinas, SP, CEP-13083-888, Brazil
| | - Gabriela Scriptore
- Cardiovascular Department, Medical Sciences Faculty, UNICAMP, Campinas, São Paulo, Brazil
| | - Fernando Cendes
- NeuroImage Laboratory, Department of Neurology, Medical Sciences Faculty, UNICAMP, Rua Vital Brasil, 251 Cidade Universitária Zeferino Vaz, Campinas, SP, CEP-13083-888, Brazil
| | - Marcio L F Balthazar
- NeuroImage Laboratory, Department of Neurology, Medical Sciences Faculty, UNICAMP, Rua Vital Brasil, 251 Cidade Universitária Zeferino Vaz, Campinas, SP, CEP-13083-888, Brazil
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17
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Musiek ES, Xiong DD, Patel T, Sasaki Y, Wang Y, Bauer AQ, Singh R, Finn SL, Culver JP, Milbrandt J, Holtzman DM. Nmnat1 protects neuronal function without altering phospho-tau pathology in a mouse model of tauopathy. Ann Clin Transl Neurol 2016; 3:434-42. [PMID: 27547771 PMCID: PMC4891997 DOI: 10.1002/acn3.308] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 03/18/2016] [Accepted: 03/21/2016] [Indexed: 12/25/2022] Open
Abstract
Objective The nicotinamide‐nucleotide adenylyltransferase protein Nmnat1 is a potent inhibitor of axonal degeneration in models of acute axonal injury. Hyperphosphorylation and aggregation of the microtubule‐associated protein Tau are associated with neurodegeneration in Alzheimer's Disease and other disorders. Previous studies have demonstrated that other Nmnat isoforms can act both as axonoprotective agents and have protein chaperone function, exerting protective effects in drosophila and mouse models of tauopathy. Nmnat1 targeted to the cytoplasm (cytNmnat1) is neuroprotective in a mouse model of neonatal hypoxia‐ischemia, but the effect of cytNmnat1 on tauopathy remains unknown. Methods We examined the impact of overexpression of cytNmnat1 on tau pathology, neurodegeneration, and brain functional connectivity in the P301S mouse model of chronic tauopathy. Results Overexpression of cytNmnat1 preserved cortical neuron functional connectivity in P301S mice in vivo. However, whereas Nmnat1 overexpression decreased the accumulation of detergent‐insoluble tau aggregates in the cerebral cortex, it exerted no effect on immunohistochemical evidence of pathologic tau phosphorylation and misfolding, hippocampal atrophy, or inflammatory markers in P301S mice. Interpretation Our results demonstrate that cytNmnat1 partially preserves neuronal function and decreases biochemically insoluble tau in a mouse model of chronic tauopathy without preventing tau phosphorylation, formation of soluble aggregates, or tau‐induced inflammation and atrophy. Nmnat1 might thus represent a therapeutic target for tauopathies.
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Affiliation(s)
- Erik S Musiek
- Departments of Neurology Washington University School of Medicine St. Louis Missouri; Hope Center for Neurological Disorders Washington University School of Medicine St. Louis Missouri; Knight Alzheimer's Disease Research Center Washington University School of Medicine St. Louis Missouri
| | - David D Xiong
- Departments of Neurology Washington University School of Medicine St. Louis Missouri; Hope Center for Neurological Disorders Washington University School of Medicine St. Louis Missouri; Knight Alzheimer's Disease Research Center Washington University School of Medicine St. Louis Missouri
| | - Tirth Patel
- Departments of Neurology Washington University School of Medicine St. Louis Missouri; Hope Center for Neurological Disorders Washington University School of Medicine St. Louis Missouri; Knight Alzheimer's Disease Research Center Washington University School of Medicine St. Louis Missouri
| | - Yo Sasaki
- Genetics Washington University School of Medicine St. Louis Missouri
| | - Yinong Wang
- Departments of Neurology Washington University School of Medicine St. Louis Missouri; Hope Center for Neurological Disorders Washington University School of Medicine St. Louis Missouri; Knight Alzheimer's Disease Research Center Washington University School of Medicine St. Louis Missouri
| | - Adam Q Bauer
- Radiology Washington University School of Medicine St. Louis Missouri
| | - Risham Singh
- Departments of Neurology Washington University School of Medicine St. Louis Missouri; Hope Center for Neurological Disorders Washington University School of Medicine St. Louis Missouri; Knight Alzheimer's Disease Research Center Washington University School of Medicine St. Louis Missouri
| | - Samantha L Finn
- Departments of Neurology Washington University School of Medicine St. Louis Missouri; Hope Center for Neurological Disorders Washington University School of Medicine St. Louis Missouri; Knight Alzheimer's Disease Research Center Washington University School of Medicine St. Louis Missouri
| | - Joseph P Culver
- Radiology Washington University School of Medicine St. Louis Missouri
| | - Jeffrey Milbrandt
- Genetics Washington University School of Medicine St. Louis Missouri
| | - David M Holtzman
- Departments of Neurology Washington University School of Medicine St. Louis Missouri; Hope Center for Neurological Disorders Washington University School of Medicine St. Louis Missouri; Knight Alzheimer's Disease Research Center Washington University School of Medicine St. Louis Missouri
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18
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Alterations in the expression of Per1 and Per2 induced by Aβ31-35 in the suprachiasmatic nucleus, hippocampus, and heart of C57BL/6 mouse. Brain Res 2016; 1642:51-58. [PMID: 27021954 DOI: 10.1016/j.brainres.2016.03.026] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 03/14/2016] [Accepted: 03/18/2016] [Indexed: 12/29/2022]
Abstract
Patients with Alzheimer's disease (AD) have circadian rhythm disorders, which are mimicked in 3xTg-AD and 5xFAD mouse models. The deposition of β-amyloid protein (Aβ) is an important pathological characteristic of AD, however, its role in inducing alterations in biological rhythms and in the expression of circadian clock-related genes remains elusive. The Per1 and Per2 play complex regulatory roles in biological clocks and are diffusely expressed in the suprachiasmatic nucleus (SCN), hippocampus and heart. In the present study, wheel-running behavioral experiments showed that Aβ31-35, which was administered into the hippocampus, resulted in the disruption of the circadian rhythm of C57BL/6 mice. Furthermore, real-time PCR and western blot analysis showed that Aβ31-35 altered the expression of the Per1 and Per2 in the SCN, hippocampus and heart. These findings provide experimental evidence for circadian rhythm disturbances in patients with AD.
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19
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LIU HONG, CHU WENZHENG, GONG LI, GAO XIAOYU, WANG WEI. MicroRNA-26b is upregulated in a double transgenic mouse model of Alzheimer's disease and promotes the expression of amyloid-β by targeting insulin-like growth factor 1. Mol Med Rep 2016; 13:2809-14. [DOI: 10.3892/mmr.2016.4860] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 12/18/2015] [Indexed: 11/05/2022] Open
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20
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Liang W, Zhang W, Zhao S, Li Q, Liang H, Ceng R. Altered expression of neurofilament 200 and amyloid-β peptide (1-40) in a rat model of chronic cerebral hypoperfusion. Neurol Sci 2014; 36:707-12. [PMID: 25452168 DOI: 10.1007/s10072-014-2014-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 11/19/2014] [Indexed: 12/21/2022]
Abstract
Chronic cerebral hypoperfusion (CCH) is damaging to white matter in the brain. So far few studies have investigated long-term axonal damage following CCH. The aim of this study was to investigate the involvement of neurofilament 200 (NF200) and amyloid-β (1-40) [Aβ (1-40)] in the pathological mechanism for neuronal damage, and to quantify changes in their expression over time in a rat model of CCH. A rat model of CCH was established using partial bilateral ligation of the common carotid arteries. The extent of stenosis was verified by measuring the changes in cerebral blood flow after surgery. Histology was used to assess hippocampal neuronal pathology, and immunohistochemistry was used to quantify the expression of NF200 and Aβ (1-40) at 2, 4, and 12 weeks after surgery. The cerebral blood flow reduced to 33.89 ± 5.48 % at 2 weeks, 36.83 ± 4.63 % at 4 weeks and 51.44 ± 4.90 % at 12 weeks. Immunofluorescence staining of neuronal perikarya sections revealed a marked decrease in the population of surviving pyramidal cells in the hippocampal CA1 region, a significant up-regulation in the expression of Aβ (1-40), and a significant reduction in the expression of NF200 following CCH surgery. Moreover, this trend was increasingly obvious over time. Our data demonstrate that CCH leads to axonal damage over time. We also confirmed that the expression of Aβ (1-40) and NF200 may be useful biomarkers of axonal damage following CCH.
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Affiliation(s)
- Weihua Liang
- Department of Neurology, Xinqiao Hospital, The Third Military Medical University, No. 183 Xinqiao Street, Shapingba District, Chongqing, 400038, China,
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21
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Christensen DZ, Huettenrauch M, Mitkovski M, Pradier L, Wirths O. Axonal degeneration in an Alzheimer mouse model is PS1 gene dose dependent and linked to intraneuronal Aβ accumulation. Front Aging Neurosci 2014; 6:139. [PMID: 25018730 PMCID: PMC4073286 DOI: 10.3389/fnagi.2014.00139] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 06/11/2014] [Indexed: 11/25/2022] Open
Abstract
Abnormalities and impairments in axonal transport are suggested to strongly contribute to the pathological alterations underlying AD. The exact mechanisms leading to axonopathy are currently unclear, but it was recently suggested that APP expression itself triggers axonal degeneration. We used APP transgenic mice and crossed them on a hemi- or homozygous PS1 knock-in background (APP/PS1KI). Depending on the mutant PS1 dosage, we demonstrate a clear aggravation in both plaque-associated and plaque-distant axonal degeneration, despite of an unchanged APP expression level. Amyloid-β (Aβ) peptides were found to accumulate in axonal swellings as well as in axons and apical dendrites proximate to neurons accumulating intraneuronal Aβ in their cell bodies. This suggests that Aβ can be transported within neurites thereby contributing to axonal deficits. In addition, diffuse extracellular Aβ deposits were observed in the close vicinity of axonal spheroids accumulating intracellular Aβ, which might be indicative of a local Aβ release from sites of axonal damage.
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Affiliation(s)
- Ditte Z Christensen
- Division of Molecular Psychiatry, Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University Goettingen, Germany
| | - Melanie Huettenrauch
- Division of Molecular Psychiatry, Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University Goettingen, Germany
| | - Miso Mitkovski
- Light Microscopy Facility, Max-Planck-Institute of Experimental Medicine Goettingen, Germany
| | - Laurent Pradier
- Central Nervous System Department, Centre de Recherche Vitry-Alfortville, Sanofi-Aventis Vitry-sur-Seine, France
| | - Oliver Wirths
- Division of Molecular Psychiatry, Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University Goettingen, Germany
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22
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Tau hyperphosphorylation induces apoptotic escape and triggers neurodegeneration in Alzheimer's disease. Neurosci Bull 2014; 30:359-66. [PMID: 24627329 DOI: 10.1007/s12264-013-1415-y] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 01/27/2014] [Indexed: 12/18/2022] Open
Abstract
Since abnormal post-translational modifications or gene mutations of tau have been detected in over twenty neurodegenerative disorders, tau has attracted widespread interest as a target protein. Among its various post-translational modifications, phosphorylation is the most extensively studied. It is recognized that tau hyperphosphorylation is the root cause of neurodegeneration in Alzheimer's disease (AD); however, it is not clear how it causes neurodegeneration. Based on the findings that tau hyperphosphorylation leads to the escape of neurons from acute apoptosis and simultaneously impairs the function of neurons, we have proposed that the nature of AD neurodegeneration is the consequence of aborted apoptosis induced by tau phosphorylation. Therefore, proper manipulation of tau hyperphosphorylation could be promising for arresting AD neurodegeneration. In this review, the neuroprotective and neurodegenerative effects of tau hyperphosphorylation and our thoughts regarding their relationship are presented.
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23
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Li X, Ma Y, Wei X, Li Y, Wu H, Zhuang J, Zhao Z. Clusterin in Alzheimer's disease: a player in the biological behavior of amyloid-beta. Neurosci Bull 2013; 30:162-8. [PMID: 24353014 DOI: 10.1007/s12264-013-1391-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 05/29/2013] [Indexed: 12/17/2022] Open
Abstract
Alzheimer's disease (AD) remains a major killer, and although its pathogenesis varies, one dominant feature is an increase in the expression, formation, and sedimentation of senile plaques of amyloid-beta (Aβ) peptides in the brain. The chaperone protein clusterin has, since its first discovery at the end of the 20(th) century, been labeled as a cytoprotector. However, epigenetic studies showing that clusterin is associated with the severity and risk of AD, especially in the hippocampus, triggered studies to clarify its role in the pathogenesis of AD. It is true that clusterin can inhibit the aggregation of Aβ and therefore prevent further formation of senile plaques in the AD brain, yet it induces the formation of soluble forms of Aβ which are toxic to neurons. Another problematic finding is that clusterin is involved in a pathway through which Aβ has neurodegenerative effects intracellularly. Although the role of clusterin in the pathogenesis of AD is still not clear, this review specifically discusses the interactions between clusterin and Aβ, to open up the possibility of a potential therapeutic approach for treating AD.
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Affiliation(s)
- Xiang Li
- Department of Neurology, Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China
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Krstic D, Knuesel I. The airbag problem-a potential culprit for bench-to-bedside translational efforts: relevance for Alzheimer's disease. Acta Neuropathol Commun 2013; 1:62. [PMID: 24252346 PMCID: PMC3893418 DOI: 10.1186/2051-5960-1-62] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 09/16/2013] [Indexed: 11/10/2022] Open
Abstract
For the last 20 years, the "amyloid cascade hypothesis" has dominated research aimed at understanding, preventing, and curing Alzheimer's disease (AD). During that time researchers have acquired an enormous amount of data and have been successful, more than 300 times, in curing the disease in animal model systems by treatments aimed at clearing amyloid deposits. However, to date similar strategies have not been successful in human AD patients. Hence, before rushing into further clinical trials with compounds that aim at lowering amyloid-beta (Aβ) levels in increasingly younger people, it would be of highest priority to re-assess the initial assumption that accumulation of Aβ in the brain is the primary pathological event driving AD. Here we question this assumption by highlighting experimental evidence in support of the alternative hypothesis suggesting that APP and Aβ are part of a neuronal stress/injury system, which is up-regulated to counteract inflammation/oxidative stress-associated neurodegeneration that could be triggered by a brain injury, chronic infections, or a systemic disease. In AD, this protective program may be overridden by genetic and other risk factors, or its maintenance may become dysregulated during aging. Here, we provide a hypothetical example of a hypothesis-driven correlation between car accidents and airbag release in analogy to the evolution of the amyloid focus and as a way to offer a potential explanation for the failure of the AD field to translate the success of amyloid-related therapeutic strategies in experimental models to the clinic.
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MicroRNA-98 induces an Alzheimer's disease-like disturbance by targeting insulin-like growth factor 1. Neurosci Bull 2013; 29:745-51. [PMID: 23740209 DOI: 10.1007/s12264-013-1348-5] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 01/16/2013] [Indexed: 12/20/2022] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by extracellular senile plaques and intracellular neurofibrillary tangles. Many microRNAs (miRs) participate in regulating amyloid β (Aβ) formation and the metabolism of tau protein in the process of AD, and some are up-regulated in AD patients or transgenic models of AD. However, the role of miR-98 in AD remains unclear. Here, we showed that the expression of miR-98 was negatively correlated with the insulin-like growth factor 1 (IGF-1) protein level in APP/PS1 mice. MiR-98 target sites in IGF-1 were confirmed by luciferase assay in HEK293 cells. Overexpression of miR-98 in N2a/APP cells down-regulated the IGF-1 protein level and promoted Aβ production, whereas inhibition of miR-98 in N2a/APP cells up-regulated the IGF-1 protein level and suppressed Aβ production. Furthermore, overexpression of miR-98 in N2a/WT cells increased the phosphorylation of tau, whereas inhibition of miR-98 reduced it. These results suggest that miR-98 increases Aβ formation and tau phosphorylation by inhibiting the translation of IGF-1, which might provide a therapeutic strategy for AD.
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Abstract
Despite tremendous investments in understanding the complex molecular mechanisms underlying Alzheimer disease (AD), recent clinical trials have failed to show efficacy. A potential problem underlying these failures is the assumption that the molecular mechanism mediating the genetically determined form of the disease is identical to the one resulting in late-onset AD. Here, we integrate experimental evidence outside the 'spotlight' of the genetic drivers of amyloid-β (Aβ) generation published during the past two decades, and present a mechanistic explanation for the pathophysiological changes that characterize late-onset AD. We propose that chronic inflammatory conditions cause dysregulation of mechanisms to clear misfolded or damaged neuronal proteins that accumulate with age, and concomitantly lead to tau-associated impairments of axonal integrity and transport. Such changes have several neuropathological consequences: focal accumulation of mitochondria, resulting in metabolic impairments; induction of axonal swelling and leakage, followed by destabilization of synaptic contacts; deposition of amyloid precursor protein in swollen neurites, and generation of aggregation-prone peptides; further tau hyperphosphorylation, ultimately resulting in neurofibrillary tangle formation and neuronal death. The proposed sequence of events provides a link between Aβ and tau-related neuropathology, and underscores the concept that degenerating neurites represent a cause rather than a consequence of Aβ accumulation in late-onset AD.
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Transient focal cerebral ischemia/reperfusion induces early and chronic axonal changes in rats: its importance for the risk of Alzheimer's disease. PLoS One 2012; 7:e33722. [PMID: 22457786 PMCID: PMC3311543 DOI: 10.1371/journal.pone.0033722] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 02/15/2012] [Indexed: 11/19/2022] Open
Abstract
The dementia of Alzheimer's type and brain ischemia are known to increase at comparable rates with age. Recent advances suggest that cerebral ischemia may contribute to the pathogenesis of Alzheimer's disease (AD), however, the neuropathological relationship between these two disorders is largely unclear. It has been demonstrated that axonopathy, mainly manifesting as impairment of axonal transport and swelling of the axon and varicosity, is a prominent feature in AD and may play an important role in the neuropathological mechanisms in AD. In this study, we investigated the early and chronic changes of the axons of neurons in the different brain areas (cortex, hippocampus and striatum) using in vivo tracing technique and grading analysis method in a rat model of transient focal cerebral ischemia/reperfusion (middle cerebral artery occlusion, MCAO). In addition, the relationship between the changes of axons and the expression of β-amyloid 42 (Aβ42) and hyperphosphorylated Tau, which have been considered as the key neuropathological processes of AD, was analyzed by combining tracing technique with immunohistochemistry or western blotting. Subsequently, we found that transient cerebral ischemia/reperfusion produced obvious swelling of the axons and varicosities, from 6 hours after transient cerebral ischemia/reperfusion even up to 4 weeks. We could not observe Aβ plaques or overexpression of Aβ42 in the ischemic brain areas, however, the site-specific hyperphosphorylated Tau could be detected in the ischemic cortex. These results suggest that transient cerebral ischemia/reperfusion induce early and chronic axonal changes, which may be an important mechanism affecting the clinical outcome and possibly contributing to the development of AD after stroke.
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