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Pena E, San Martin-Salamanca R, El Alam S, Flores K, Arriaza K. Tau Protein Alterations Induced by Hypobaric Hypoxia Exposure. Int J Mol Sci 2024; 25:889. [PMID: 38255962 PMCID: PMC10815386 DOI: 10.3390/ijms25020889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 12/21/2023] [Accepted: 01/05/2024] [Indexed: 01/24/2024] Open
Abstract
Tauopathies are a group of neurodegenerative diseases whose central feature is dysfunction of the microtubule-associated protein tau (MAPT). Although the exact etiology of tauopathies is still unknown, it has been hypothesized that their onset may occur up to twenty years before the clear emergence of symptoms, which has led to questions about whether the prognosis of these diseases can be improved by, for instance, targeting the factors that influence tauopathy development. One such factor is hypoxia, which is strongly linked to Alzheimer's disease because of its association with obstructive sleep apnea and has been reported to affect molecular pathways related to the dysfunction and aggregation of tau proteins and other biomarkers of neurological damage. In particular, hypobaric hypoxia exposure increases the activation of several kinases related to the hyperphosphorylation of tau in neuronal cells, such as ERK, GSK3β, and CDK5. In addition, hypoxia also increases the levels of inflammatory molecules (IL-β1, IL-6, and TNF-α), which are also associated with neurodegeneration. This review discusses the many remaining questions regarding the influence of hypoxia on tauopathies and the contribution of high-altitude exposure to the development of these diseases.
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Affiliation(s)
| | | | - Samia El Alam
- High Altitude Medicine Research Center (CEIMA), Arturo Prat University, Iquique 1110939, Chile; (E.P.); (R.S.M.-S.); (K.F.); (K.A.)
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2
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Banerjee S, Banerjee S. Amyloid Beta-Mediated Neurovascular Toxicity in Alzheimer's Disease. Methods Mol Biol 2024; 2761:355-372. [PMID: 38427250 DOI: 10.1007/978-1-0716-3662-6_26] [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] [Indexed: 03/02/2024]
Abstract
The brain vascular system receives one-fifth of the total oxygen from the cardiac output, and this transport system is highly dependent on blood-brain barrier (BBB) integrity. The cerebral blood flow is controlled by neurovascular coupling through neurovascular units (NVUs). The NVU includes different types of cells, such as mural cells, astrocytes, pericytes, endothelial cells (ECs), and vascular smooth muscle cells (VSMCs). The cellular composition of NVU varies throughout the vascular tree. Amyloid β (Aβ) is abundantly present in the central nervous system, but the pathological accumulation of misfolded Aβ protein causes vascular damage, resulting in neurovascular dysfunction. Aβ aggregation can activate the astrocytes and endothelial cells. It is followed by pericyte degeneration which results in dysregulation of cerebral blood flow (CBF), neurovascular uncoupling, and BBB breakdown. Thus, understanding the cellular and molecular mechanisms of Aβ-induced neurovascular toxicity is crucial for determining normal and diseased brain function. This chapter discusses the components of NVU, neurovascular uncoupling, Aβ-induced cerebrovascular reactivity, and cerebral blood flow reduction in neurodegenerative disorders, with special emphasis on Alzheimer's disease.
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Affiliation(s)
- Sayani Banerjee
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Kolkata, India
| | - Sugato Banerjee
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Kolkata, India
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3
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Yang C, Zhou Y, Liu H, Xu P. The Role of Inflammation in Cognitive Impairment of Obstructive Sleep Apnea Syndrome. Brain Sci 2022; 12:brainsci12101303. [PMID: 36291237 PMCID: PMC9599901 DOI: 10.3390/brainsci12101303] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 09/14/2022] [Accepted: 09/20/2022] [Indexed: 11/16/2022] Open
Abstract
Obstructive sleep apnea syndrome (OSAS) has become a major worldwide public health concern, given its global prevalence. It has clear links with multiple comorbidities and mortality. Cognitive impairment is one related comorbidity causing great pressure on individuals and society. The clinical manifestations of cognitive impairment in OSAS include decline in attention/vigilance, verbal–visual memory loss, visuospatial/structural ability impairment, and executive dysfunction. It has been proven that chronic intermittent hypoxia (CIH) may be a main cause of cognitive impairment in OSAS. Inflammation plays important roles in CIH-induced cognitive dysfunction. Furthermore, the nuclear factor kappa B and hypoxia-inducible factor 1 alpha pathways play significant roles in this inflammatory mechanism. Continuous positive airway pressure is an effective therapy for OSAS; however, its effect on cognitive impairment is suboptimal. Therefore, in this review, we address the role inflammation plays in the development of neuro-impairment in OSAS and the association between OSAS and cognitive impairment to provide an overview of its pathophysiology. We believe that furthering the understanding of the inflammatory mechanisms involved in OSAS-associated cognitive impairment could lead to the development of appropriate and effective therapy.
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Sanderlin AH, Hayden KM, Baker LD, Craft S. Ketogenic dietary lifestyle intervention effects on sleep, cognition, and behavior in mild cognitive impairment: Study design. ALZHEIMER'S & DEMENTIA (NEW YORK, N. Y.) 2022; 8:e12343. [PMID: 36177445 PMCID: PMC9473641 DOI: 10.1002/trc2.12343] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 06/30/2022] [Accepted: 07/02/2022] [Indexed: 12/02/2022]
Abstract
Introduction Sleep and diet are modifiable risk factors for Alzheimer's disease (AD) that may be salient areas for the development of preventive intervention strategies against dementia in people with mild cognitive impairment (MCI). Sleep disturbances account for up to 15% of the population attributable risk for AD. Diet influences sleep quality, such that diets high in sugars, fat, and processed food affect sleep quality and cognition in older adults. The combination of poor sleep and diet health may increase risk for dementia in people with MCI, yet it is unknown how intervening on diet may influence sleep health. Methods The MCI Sleep Study assesses longitudinal changes in objective and subjective measures of sleep between two investigational diet groups in the Brain Energy for Amyloid Transformation in Alzheimer's Disease study: the modified Mediterranean ketogenic diet (MMKD) and the American Heart Association diet. Objective sleep assessments include an in-home sleep study using the WatchPAT Central Plus (Itamar Medical, Ltd) at baseline and the end of the 4-month diet intervention. Subjective sleep questionnaires include the Epworth Sleepiness Scale and Pittsburgh Sleep Quality Index. The MCI Sleep Study outcome measures include longitudinal change in cognitive performance, mood, behavior, and quality of life. Results Study recruitment is currently ongoing. We hypothesize the low-carb MMKD diet to have a beneficial impact on sleep health in individuals with MCI. Pre- and post-diet changes in sleep metrics across diet groups will be examined using mixed effects analysis of variance models. Discussion Early assessment of chronic sleep and diet behaviors may be vital in understanding when interventions are necessary and the lifestyle modifications that should accompany future AD prevention and therapy recommendations.
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Affiliation(s)
- Ashley H. Sanderlin
- Department of Internal Medicine—Gerontology and Geriatric MedicineWake Forest University School of MedicineWinston‐SalemNorth CarolinaUSA
| | - Kathleen M. Hayden
- Department of Social Sciences and Health PolicyWake Forest University School of MedicineWinston‐SalemNorth CarolinaUSA
| | - Laura D. Baker
- Department of Internal Medicine—Gerontology and Geriatric MedicineWake Forest University School of MedicineWinston‐SalemNorth CarolinaUSA
- Department of Social Sciences and Health PolicyWake Forest University School of MedicineWinston‐SalemNorth CarolinaUSA
| | - Suzanne Craft
- Department of Internal Medicine—Gerontology and Geriatric MedicineWake Forest University School of MedicineWinston‐SalemNorth CarolinaUSA
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5
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Custodia A, Ouro A, Romaus-Sanjurjo D, Pías-Peleteiro JM, de Vries HE, Castillo J, Sobrino T. Endothelial Progenitor Cells and Vascular Alterations in Alzheimer’s Disease. Front Aging Neurosci 2022; 13:811210. [PMID: 35153724 PMCID: PMC8825416 DOI: 10.3389/fnagi.2021.811210] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 12/14/2021] [Indexed: 12/14/2022] Open
Abstract
Alzheimer’s disease (AD) is a neurodegenerative disease representing the most common type of dementia worldwide. The early diagnosis of AD is very difficult to achieve due to its complexity and the practically unknown etiology. Therefore, this is one of the greatest challenges in the field in order to develop an accurate therapy. Within the different etiological hypotheses proposed for AD, we will focus on the two-hit vascular hypothesis and vascular alterations occurring in the disease. According to this hypothesis, the accumulation of β-amyloid protein in the brain starts as a consequence of damage in the cerebral vasculature. Given that there are several vascular and angiogenic alterations in AD, and that endothelial progenitor cells (EPCs) play a key role in endothelial repair processes, the study of EPCs in AD may be relevant to the disease etiology and perhaps a biomarker and/or therapeutic target. This review focuses on the involvement of endothelial dysfunction in the onset and progression of AD with special emphasis on EPCs as a biomarker and potential therapeutic target.
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Affiliation(s)
- Antía Custodia
- NeuroAging Group (NEURAL), Clinical Neurosciences Research Laboratory (LINC), Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain
| | - Alberto Ouro
- NeuroAging Group (NEURAL), Clinical Neurosciences Research Laboratory (LINC), Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain
- *Correspondence: Alberto Ouro,
| | - Daniel Romaus-Sanjurjo
- NeuroAging Group (NEURAL), Clinical Neurosciences Research Laboratory (LINC), Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain
| | - Juan Manuel Pías-Peleteiro
- NeuroAging Group (NEURAL), Clinical Neurosciences Research Laboratory (LINC), Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain
| | - Helga E. de Vries
- Neuroimmunology Research Group, Department of Molecular Cell Biology and Immunology, Amsterdam Neuroscience, Amsterdam UMC, Amsterdam, Netherlands
| | - José Castillo
- Neuroimaging and Biotechnology Laboratory (NOBEL), Clinical Neurosciences Research Laboratory (LINC), Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain
| | - Tomás Sobrino
- NeuroAging Group (NEURAL), Clinical Neurosciences Research Laboratory (LINC), Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain
- Tomás Sobrino,
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6
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Inuzuka H, Liu J, Wei W, Rezaeian AH. PROTACs technology for treatment of Alzheimer's disease: Advances and perspectives. ACTA MATERIA MEDICA 2022; 1:24-41. [PMID: 35237768 PMCID: PMC8887676 DOI: 10.15212/amm-2021-0001] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
Neurodegenerative diseases (NDs) are characteristic with progression of neuron degeneration, resulting in dysfunction of cognition and mobility. Many neurodegenerative diseases are because of proteinopathies that results from unusual protein accumulations and aggregations. The aggregation of misfolded proteins like β-amyloid, α-synuclein, tau, and polyglutamates are hallmarked in Alzheimer's disease (AD), which are undruggable targets, and usually do not respond to conventional small-molecule agents. Therefore, developing novel technology and strategy for reducing the levels of protein aggregates would be critical for treatment of AD. Recently, the emerging proteolysis targeting chimeras (PRPTACs) technology has been significantly considered for artificial and selective degradation of aberrant target proteins. These engineered bifunctional molecules engage target proteins to be degraded by either the cellular degradation machinery in the ubiquitin-proteasome system (UPS) or via the autophagy-lysosome degradation pathway. Although the application of PROTACs technology is preferable than oligonucleotide and antibodies for treatment of NDs, many limitations such as their pharmacokinetic properties, tissue distribution and cell permeabilities, still need to be corrected. Herein, we review the recent advances in PROTACs technology with their limitation for pharmaceutical targeting of aberrant proteins involved in Alzheimer's diseases. We also review therapeutic potential of dysregulated signaling such as PI3K/AKT/mTOR axis for the management of AD.
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Affiliation(s)
- Hiroyuki Inuzuka
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Jing Liu
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Wenyi Wei
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
- Corresponding author. Contact: ,
| | - Abdol-Hossein Rezaeian
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
- Corresponding author. Contact: ,
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7
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Ulland TK, Ewald AC, Knutson AO, Marino KM, Smith SMC, Watters JJ. Alzheimer's Disease, Sleep Disordered Breathing, and Microglia: Puzzling out a Common Link. Cells 2021; 10:2907. [PMID: 34831129 PMCID: PMC8616348 DOI: 10.3390/cells10112907] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 10/22/2021] [Accepted: 10/24/2021] [Indexed: 12/14/2022] Open
Abstract
Sleep Disordered Breathing (SDB) and Alzheimer's Disease (AD) are strongly associated clinically, but it is unknown if they are mechanistically associated. Here, we review data covering both the cellular and molecular responses in SDB and AD with an emphasis on the overlapping neuroimmune responses in both diseases. We extensively discuss the use of animal models of both diseases and their relative utilities in modeling human disease. Data presented here from mice exposed to intermittent hypoxia indicate that microglia become more activated following exposure to hypoxia. This also supports the idea that intermittent hypoxia can activate the neuroimmune system in a manner like that seen in AD. Finally, we highlight similarities in the cellular and neuroimmune responses between SDB and AD and propose that these similarities may lead to a pathological synergy between SDB and AD.
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Affiliation(s)
- Tyler K. Ulland
- Department of Pathology and Laboratory Medicine, University of Wisconsin Madison, Madison, WI 53705, USA; (T.K.U.); (K.M.M.)
- Neuroscience Training Program, University of Wisconsin Madison, Madison, WI 53705, USA
| | - Andrea C. Ewald
- Department of Comparative Biosciences, University of Wisconsin Madison, Madison, WI 53706, USA; (A.C.E.); (A.O.K.); (S.M.C.S.)
| | - Andrew O. Knutson
- Department of Comparative Biosciences, University of Wisconsin Madison, Madison, WI 53706, USA; (A.C.E.); (A.O.K.); (S.M.C.S.)
| | - Kaitlyn M. Marino
- Department of Pathology and Laboratory Medicine, University of Wisconsin Madison, Madison, WI 53705, USA; (T.K.U.); (K.M.M.)
- Neuroscience Training Program, University of Wisconsin Madison, Madison, WI 53705, USA
| | - Stephanie M. C. Smith
- Department of Comparative Biosciences, University of Wisconsin Madison, Madison, WI 53706, USA; (A.C.E.); (A.O.K.); (S.M.C.S.)
| | - Jyoti J. Watters
- Neuroscience Training Program, University of Wisconsin Madison, Madison, WI 53705, USA
- Department of Comparative Biosciences, University of Wisconsin Madison, Madison, WI 53706, USA; (A.C.E.); (A.O.K.); (S.M.C.S.)
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8
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Song B, Zhu JC. A Narrative Review of Cerebellar Malfunctions and Sleep Disturbances. Front Neurosci 2021; 15:590619. [PMID: 34248474 PMCID: PMC8267147 DOI: 10.3389/fnins.2021.590619] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 05/31/2021] [Indexed: 11/15/2022] Open
Abstract
Cerebellar malfunctions significantly impact the regulation of the sleep–wakefulness transition. The possible mechanism for this effect is still unknown. Evidence on the role of cerebellar processing in the sleep–wake cycle is derived mainly from animal studies, and clinical management of the sleep–wake cycle is also challenging. The purpose of this review is to investigate the role of cerebellar activity during normal sleep and the association between cerebellar dysfunction and sleep disorders. Large-scale, multicenter trials are still needed to confirm these findings and provide early identification and intervention strategies to improve cerebellar function and the sleep quality of patients.
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Affiliation(s)
- Bijia Song
- Department of Anesthesiology, Shengjing Hospital of China Medical University, Shenyang, China.,Department of Anesthesiology, Beijing Friendship Hospital of Capital Medical University, Beijing, China
| | - Jun-Chao Zhu
- Department of Anesthesiology, Shengjing Hospital of China Medical University, Shenyang, China
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9
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Paolini Paoletti F, Simoni S, Parnetti L, Gaetani L. The Contribution of Small Vessel Disease to Neurodegeneration: Focus on Alzheimer's Disease, Parkinson's Disease and Multiple Sclerosis. Int J Mol Sci 2021; 22:ijms22094958. [PMID: 34066951 PMCID: PMC8125719 DOI: 10.3390/ijms22094958] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 05/04/2021] [Accepted: 05/05/2021] [Indexed: 01/18/2023] Open
Abstract
Brain small vessel disease (SVD) refers to a variety of structural and functional changes affecting small arteries and micro vessels, and manifesting as white matter changes, microbleeds and lacunar infarcts. Growing evidence indicates that SVD might play a significant role in the neurobiology of central nervous system (CNS) neurodegenerative disorders, namely Alzheimer's disease (AD) and Parkinson's disease (PD), and neuroinflammatory diseases, such as multiple sclerosis (MS). These disorders share different pathophysiological pathways and molecular mechanisms (i.e., protein misfolding, derangement of cellular clearance systems, mitochondrial impairment and immune system activation) having neurodegeneration as biological outcome. In these diseases, the actual contribution of SVD to the clinical picture, and its impact on response to pharmacological treatments, is not known yet. Due to the high frequency of SVD in adult-aged patients, it is important to address this issue. In this review, we report preclinical and clinical data on the impact of SVD in AD, PD and MS, with the main aim of clarifying the predictability of SVD on clinical manifestations and treatment response.
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10
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Owen JE, Benediktsdottir B, Cook E, Olafsson I, Gislason T, Robinson SR. Alzheimer's disease neuropathology in the hippocampus and brainstem of people with obstructive sleep apnea. Sleep 2021; 44:5909379. [PMID: 32954401 DOI: 10.1093/sleep/zsaa195] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 09/10/2020] [Indexed: 12/23/2022] Open
Abstract
Obstructive sleep apnea (OSA) involves intermittent cessations of breathing during sleep. People with OSA can experience memory deficits and have reduced hippocampal volume; these features are also characteristic of Alzheimer's disease (AD), where they are accompanied by neurofibrillary tangles (NFTs) and amyloid beta (Aβ) plaques in the hippocampus and brainstem. We have recently shown reduced hippocampal volume to be related to OSA severity, and although OSA may be a risk factor for AD, the hippocampus and brainstems of clinically verified OSA cases have not yet been examined for NFTs and Aβ plaques. The present study used quantitative immunohistochemistry to investigate postmortem hippocampi of 34 people with OSA (18 females, 16 males; mean age 67 years) and brainstems of 24 people with OSA for the presence of NFTs and Aβ plaques. OSA severity was a significant predictor of Aβ plaque burden in the hippocampus after controlling for age, sex, body mass index (BMI), and continuous positive airway pressure (CPAP) use. OSA severity also predicted NFT burden in the hippocampus, but not after controlling for age. Although 71% of brainstems contained NFTs and 21% contained Aβ plaques, their burdens were not correlated with OSA severity. These results indicate that OSA accounts for some of the "cognitively normal" individuals who have been found to have substantial Aβ burdens, and are currently considered to be at a prodromal stage of AD.
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Affiliation(s)
- Jessica E Owen
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, Australia
| | - Bryndis Benediktsdottir
- Faculty of Medicine, University of Iceland, Reykjavik, Iceland.,Department of Sleep Medicine, Landspitali - The National University Hospital of Iceland, Reykjavik, Iceland
| | - Elizabeth Cook
- Department of Clinical Biochemistry, Landspitali - The National University Hospital of Iceland, Reykjavik, Iceland
| | - Isleifur Olafsson
- Department of Clinical Biochemistry, Landspitali - The National University Hospital of Iceland, Reykjavik, Iceland
| | - Thorarinn Gislason
- Faculty of Medicine, University of Iceland, Reykjavik, Iceland.,Department of Sleep Medicine, Landspitali - The National University Hospital of Iceland, Reykjavik, Iceland
| | - Stephen R Robinson
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, Australia.,Institute for Breathing and Sleep (IBAS), Austin Health, Heidelberg, Victoria, Australia
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11
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Kim HB, Yoo JY, Yoo SY, Lee JH, Chang W, Kim HS, Baik TK, Woo RS. Neuregulin-1 inhibits CoCl 2-induced upregulation of excitatory amino acid carrier 1 expression and oxidative stress in SH-SY5Y cells and the hippocampus of mice. Mol Brain 2020; 13:153. [PMID: 33187547 PMCID: PMC7664014 DOI: 10.1186/s13041-020-00686-2] [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: 07/09/2020] [Accepted: 10/09/2020] [Indexed: 11/10/2022] Open
Abstract
Excitatory amino acid carrier 1 (EAAC1) is an important subtype of excitatory amino acid transporters (EAATs) and is the route for neuronal cysteine uptake. CoCl2 is not only a hypoxia-mimetic reagent but also an oxidative stress inducer. Here, we found that CoCl2 induced significant EAAC1 overexpression in SH-SY5Y cells and the hippocampus of mice. Transient transfection of EAAC1 reduced CoCl2-induced cytotoxicity in SH-SY5Y cells. Based on this result, upregulation of EAAC1 expression by CoCl2 is thought to represent a compensatory response against oxidative stress in an acute hypoxic state. We further demonstrated that pretreatment with Neuregulin-1 (NRG1) rescued CoCl2-induced upregulation of EAAC1 and tau expression. NRG1 plays a protective role in the CoCl2-induced accumulation of reactive oxygen species (ROS) and reduction in antioxidative enzyme (SOD and GPx) activity. Moreover, NRG1 attenuated CoCl2-induced apoptosis and cell death. NRG1 inhibited the CoCl2-induced release of cleaved caspase-3 and reduction in Bcl-XL levels. Our novel finding suggests that NRG1 may play a protective role in hypoxia through the inhibition of oxidative stress and thereby maintain normal EAAC1 expression levels.
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Affiliation(s)
- Han-Byeol Kim
- Department of Anatomy and Neuroscience, College of Medicine, Eulji University, 143-5Jung-Gu, Yongdu-Dong, Daejeon, 301-746, Republic of Korea
| | - Ji-Young Yoo
- Department of Anatomy and Neuroscience, College of Medicine, Eulji University, 143-5Jung-Gu, Yongdu-Dong, Daejeon, 301-746, Republic of Korea
| | - Seung-Yeon Yoo
- Department of Anatomy and Neuroscience, College of Medicine, Eulji University, 143-5Jung-Gu, Yongdu-Dong, Daejeon, 301-746, Republic of Korea
| | - Jun-Ho Lee
- Department of Emergency Medical Technology, Daejeon University, Daejeon, 34520, Republic of Korea
| | - Wonseok Chang
- Department of Physiology, College of Medicine, Eulji University, Daejeon, 301-746, Republic of Korea
| | - Hye-Sun Kim
- Department of Pharmacology, College of Medicine, Seoul National University, Seoul, 110-799, Korea.,Seoul National University College of Medicine, Bundang Hospital, Sungnam, 13620, Republic of Korea
| | - Tai-Kyoung Baik
- Department of Anatomy and Neuroscience, College of Medicine, Eulji University, 143-5Jung-Gu, Yongdu-Dong, Daejeon, 301-746, Republic of Korea.
| | - Ran-Sook Woo
- Department of Anatomy and Neuroscience, College of Medicine, Eulji University, 143-5Jung-Gu, Yongdu-Dong, Daejeon, 301-746, Republic of Korea.
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13
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Wang H, Hong X, Wang Y. Mitochondrial Repair Effects of Oxygen Treatment on Alzheimer's Disease Model Mice Revealed by Quantitative Proteomics. J Alzheimers Dis 2018; 56:875-883. [PMID: 28059791 DOI: 10.3233/jad-161010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Mitochondrial dysfunction plays a pivotal role in Alzheimer's disease (AD), even before signs of AD pathology are evident. Our previous research has shown that oxygen treatment can improve cognitive function in AD model mice. To address whether oxygen treatment is beneficial to mitochondrial biology, we analyzed differential expressions of hippocampal mitochondrial proteins in AD model mice given supplementary oxygen. Numerous respiratory chain, Kreb's cycle, and glycolysis proteins were upregulated significantly after oxygen treatment, suggesting that oxygen therapy can alleviate mitochondrial damage. Furthermore, the treatment was associated with decreased expressions of some AD biomarkers, suggesting oxygen treatment to be a potential therapy for AD.
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Affiliation(s)
- Hao Wang
- College of Life Sciences and Oceanography, Shenzhen Key Laboratory of Microbial Genetic Engineering, Shenzhen University, Shenzhen, China
| | - Xiaoyu Hong
- College of Life Sciences and Oceanography, Shenzhen Key Laboratory of Microbial Genetic Engineering, Shenzhen University, Shenzhen, China
| | - Yong Wang
- College of Life Sciences and Oceanography, Shenzhen Key Laboratory of Marine Bioresources and Ecology, Shenzhen University, Shenzhen, China
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14
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Jha NK, Jha SK, Sharma R, Kumar D, Ambasta RK, Kumar P. Hypoxia-Induced Signaling Activation in Neurodegenerative Diseases: Targets for New Therapeutic Strategies. J Alzheimers Dis 2018; 62:15-38. [DOI: 10.3233/jad-170589] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Niraj Kumar Jha
- Molecular Neuroscience and Functional Genomics Laboratory, Delhi Technological University (Formerly DCE), Delhi, India
| | - Saurabh Kumar Jha
- Molecular Neuroscience and Functional Genomics Laboratory, Delhi Technological University (Formerly DCE), Delhi, India
| | - Renu Sharma
- Molecular Neuroscience and Functional Genomics Laboratory, Delhi Technological University (Formerly DCE), Delhi, India
| | - Dhiraj Kumar
- Molecular Neuroscience and Functional Genomics Laboratory, Delhi Technological University (Formerly DCE), Delhi, India
| | - Rashmi K. Ambasta
- Molecular Neuroscience and Functional Genomics Laboratory, Delhi Technological University (Formerly DCE), Delhi, India
| | - Pravir Kumar
- Molecular Neuroscience and Functional Genomics Laboratory, Delhi Technological University (Formerly DCE), Delhi, India
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15
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Wang H, Wang Y, Hong X, Li S, Wang Y. Quantitative Proteomics Reveals the Mechanism of Oxygen Treatment on Lenses of Alzheimer's Disease Model Mice. J Alzheimers Dis 2018; 54:275-86. [PMID: 27567828 DOI: 10.3233/jad-160263] [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] [Indexed: 11/15/2022]
Abstract
BACKGROUND Alzheimer's disease (AD) is a neurodegenerative disease with well-characterized pathological features. Yet the underlying mechanisms have not been resolved and an effective therapeutic approach is lacking. Cerebral hypoxia is considered a risk factor of AD. OBJECTIVE We tested whether oxygen supplementation can relieve AD symptoms and how it affects the expression levels of proteins in the lens. METHODS Triple transgenic AD model (3xTg-AD) mice were divided into oxygen treated (OT) and control (Ctrl) groups. Their cognitive performances were tested in a Morris water maze (MWM) paradigm. Then, their eye lens tissues were subjected to quantitative proteomics analysis by the iTRAQ (isobaric tags for relative and absolute quantification) method. The up- and downregulated proteins were classified according to a Gene Ontology (GO) database in PANTHER. Behavioral and proteomic data were compared between the groups. RESULTS Mice in the OT group had better learning and memorizing performance compared with the Ctrl group in MWM test. Lenses from the OT group had 205 differentially regulated proteins, relative to lenses from the Ctrl group, including proteins that are involved in the clearance of amyloid β-protein. CONCLUSION The results of this study indicate that oxygen treatment can improve cognitive function in AD model mice and alters protein expression in a manner consistent with improved redox regulation.
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Affiliation(s)
- Hao Wang
- College of Life Sciences and Oceanography, Shenzhen Key Laboratory of Microbial Genetic Engineering, Shenzhen University, Shenzhen, China
| | - Ying Wang
- College of Life Sciences and Oceanography, Shenzhen Key Laboratory of Microbial Genetic Engineering, Shenzhen University, Shenzhen, China
| | - Xiaoyu Hong
- College of Life Sciences and Oceanography, Shenzhen Key Laboratory of Microbial Genetic Engineering, Shenzhen University, Shenzhen, China
| | - Shuiming Li
- College of Life Sciences and Oceanography, Shenzhen Key Laboratory of Marine Bioresources and Ecology, Shenzhen University, Shenzhen, China
| | - Yong Wang
- College of Life Sciences and Oceanography, Shenzhen Key Laboratory of Marine Bioresources and Ecology, Shenzhen University, Shenzhen, China
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Guo J, Cheng J, North BJ, Wei W. Functional analyses of major cancer-related signaling pathways in Alzheimer's disease etiology. Biochim Biophys Acta Rev Cancer 2017; 1868:341-358. [PMID: 28694093 PMCID: PMC5675793 DOI: 10.1016/j.bbcan.2017.07.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 07/05/2017] [Accepted: 07/06/2017] [Indexed: 12/11/2022]
Abstract
Alzheimer's disease (AD) is an aging-related neurodegenerative disease and accounts for majority of human dementia. The hyper-phosphorylated tau-mediated intracellular neurofibrillary tangle and amyloid β-mediated extracellular senile plaque are characterized as major pathological lesions of AD. Different from the dysregulated growth control and ample genetic mutations associated with human cancers, AD displays damage and death of brain neurons in the absence of genomic alterations. Although various biological processes predominately governing tumorigenesis such as inflammation, metabolic alteration, oxidative stress and insulin resistance have been associated with AD genesis, the mechanistic connection of these biological processes and signaling pathways including mTOR, MAPK, SIRT, HIF, and the FOXO pathway controlling aging and the pathological lesions of AD are not well recapitulated. Hence, we performed a thorough review by summarizing the physiological roles of these key cancer-related signaling pathways in AD pathogenesis, comprising of the crosstalk of these pathways with neurofibrillary tangle and senile plaque formation to impact AD phenotypes. Importantly, the pharmaceutical investigations of anti-aging and AD relevant medications have also been highlighted. In summary, in this review, we discuss the potential role that cancer-related signaling pathways may play in governing the pathogenesis of AD, as well as their potential as future targeted strategies to delay or prevent aging-related diseases and combating AD.
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Affiliation(s)
- Jianping Guo
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Ji Cheng
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA; Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Brian J North
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Wenyi Wei
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
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17
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Kulbe JR, Hall ED. Chronic traumatic encephalopathy-integration of canonical traumatic brain injury secondary injury mechanisms with tau pathology. Prog Neurobiol 2017; 158:15-44. [PMID: 28851546 PMCID: PMC5671903 DOI: 10.1016/j.pneurobio.2017.08.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 08/09/2017] [Accepted: 08/17/2017] [Indexed: 12/14/2022]
Abstract
In recent years, a new neurodegenerative tauopathy labeled Chronic Traumatic Encephalopathy (CTE), has been identified that is believed to be primarily a sequela of repeated mild traumatic brain injury (TBI), often referred to as concussion, that occurs in athletes participating in contact sports (e.g. boxing, American football, Australian football, rugby, soccer, ice hockey) or in military combatants, especially after blast-induced injuries. Since the identification of CTE, and its neuropathological finding of deposits of hyperphosphorylated tau protein, mechanistic attention has been on lumping the disorder together with various other non-traumatic neurodegenerative tauopathies. Indeed, brains from suspected CTE cases that have come to autopsy have been confirmed to have deposits of hyperphosphorylated tau in locations that make its anatomical distribution distinct for other tauopathies. The fact that these individuals experienced repetitive TBI episodes during their athletic or military careers suggests that the secondary injury mechanisms that have been extensively characterized in acute TBI preclinical models, and in TBI patients, including glutamate excitotoxicity, intracellular calcium overload, mitochondrial dysfunction, free radical-induced oxidative damage and neuroinflammation, may contribute to the brain damage associated with CTE. Thus, the current review begins with an in depth analysis of what is known about the tau protein and its functions and dysfunctions followed by a discussion of the major TBI secondary injury mechanisms, and how the latter have been shown to contribute to tau pathology. The value of this review is that it might lead to improved neuroprotective strategies for either prophylactically attenuating the development of CTE or slowing its progression.
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Affiliation(s)
- Jacqueline R Kulbe
- Spinal Cord & Brain Injury Research Center, University of Kentucky College of Medicine, United States; Department of Neuroscience, University of Kentucky College of Medicine, United States
| | - Edward D Hall
- Spinal Cord & Brain Injury Research Center, University of Kentucky College of Medicine, United States; Department of Neuroscience, University of Kentucky College of Medicine, United States.
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18
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Wennberg AMV, Wu MN, Rosenberg PB, Spira AP. Sleep Disturbance, Cognitive Decline, and Dementia: A Review. Semin Neurol 2017; 37:395-406. [PMID: 28837986 DOI: 10.1055/s-0037-1604351] [Citation(s) in RCA: 143] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
AbstractApproximately half of older people report sleep disturbances, which are associated with various health conditions, including neurodegenerative disease and dementia. Indeed, 60 to 70% of people with cognitive impairment or dementia have sleep disturbances, which are linked to poorer disease prognosis. Sleep disturbances in people with dementia have long been recognized and studied; however, in the past 10 years, researchers have begun to study disturbed sleep, including sleep fragmentation, abnormal sleep duration, and sleep disorders, as risk factors for dementia. In this review the authors summarize evidence linking sleep disturbance and dementia. They describe how specific aspects of sleep (e.g., quality, duration) and the prevalence of clinical sleep disorders (e.g., sleep-disordered breathing, rapid eye movement sleep behavior disorder) change with age; how sleep parameters and sleep disorders are associated with the risk of dementia; how sleep can be disturbed in dementia; and how disturbed sleep affects dementia prognosis. These findings highlight the potential importance of identifying and treating sleep problems and disorders in middle-aged and older adults as a strategy to prevent cognitive decline and dementia. The authors also review recent evidence linking sleep disturbances to the pathophysiology underlying dementing conditions, and briefly summarize available treatments for sleep disorders in people with dementia.
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Affiliation(s)
| | - Mark N Wu
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, Maryland.,Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Paul B Rosenberg
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Adam P Spira
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland.,Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.,Johns Hopkins Center on Aging and Health, Baltimore, Maryland
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Minhas G, Mathur D, Ragavendrasamy B, Sharma NK, Paanu V, Anand A. Hypoxia in CNS Pathologies: Emerging Role of miRNA-Based Neurotherapeutics and Yoga Based Alternative Therapies. Front Neurosci 2017; 11:386. [PMID: 28744190 PMCID: PMC5504619 DOI: 10.3389/fnins.2017.00386] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Accepted: 06/20/2017] [Indexed: 12/14/2022] Open
Abstract
Cellular respiration is a vital process for the existence of life. Any condition that results in deprivation of oxygen (also termed as hypoxia) may eventually lead to deleterious effects on the functioning of tissues. Brain being the highest consumer of oxygen is prone to increased risk of hypoxia-induced neurological insults. This in turn has been associated with many diseases of central nervous system (CNS) such as stroke, Alzheimer's, encephalopathy etc. Although several studies have investigated the pathophysiological mechanisms underlying ischemic/hypoxic CNS diseases, the knowledge about protective therapeutic strategies to ameliorate the affected neuronal cells is meager. This has augmented the need to improve our understanding of the hypoxic and ischemic events occurring in the brain and identify novel and alternate treatment modalities for such insults. MicroRNA (miRNAs), small non-coding RNA molecules, have recently emerged as potential neuroprotective agents as well as targets, under hypoxic conditions. These 18-22 nucleotide long RNA molecules are profusely present in brain and other organs and function as gene regulators by cleaving and silencing the gene expression. In brain, these are known to be involved in neuronal differentiation and plasticity. Therefore, targeting miRNA expression represents a novel therapeutic approach to intercede against hypoxic and ischemic brain injury. In the first part of this review, we will discuss the neurophysiological changes caused as a result of hypoxia, followed by the contribution of hypoxia in the neurodegenerative diseases. Secondly, we will provide recent updates and insights into the roles of miRNA in the regulation of genes in oxygen and glucose deprived brain in association with circadian rhythms and how these can be targeted as neuroprotective agents for CNS injuries. Finally, we will emphasize on alternate breathing or yogic interventions to overcome the hypoxia associated anomalies that could ultimately lead to improvement in cerebral perfusion.
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Affiliation(s)
- Gillipsie Minhas
- Neuroscience Research Lab, Department of Neurology, Post Graduate Institute of Medical Education and ResearchChandigarh, India
| | - Deepali Mathur
- Faculty of Biological Sciences, University of ValenciaValencia, Spain
| | | | - Neel K. Sharma
- Armed Forces Radiobiology Research InstituteBethesda, MD, United States
| | - Viraaj Paanu
- Government Medical College and HospitalChandigarh, India
| | - Akshay Anand
- Neuroscience Research Lab, Department of Neurology, Post Graduate Institute of Medical Education and ResearchChandigarh, India
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20
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Yu L, Chen Y, Wang W, Xiao Z, Hong Y. Multi-Vitamin B Supplementation Reverses Hypoxia-Induced Tau Hyperphosphorylation and Improves Memory Function in Adult Mice. J Alzheimers Dis 2016; 54:297-306. [DOI: 10.3233/jad-160329] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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21
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Kerridge C, Kozlova DI, Nalivaeva NN, Turner AJ. Hypoxia Affects Neprilysin Expression Through Caspase Activation and an APP Intracellular Domain-dependent Mechanism. Front Neurosci 2015; 9:426. [PMID: 26617481 PMCID: PMC4643132 DOI: 10.3389/fnins.2015.00426] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 10/20/2015] [Indexed: 12/12/2022] Open
Abstract
While gene mutations in the amyloid precursor protein (APP) and the presenilins lead to an accumulation of the amyloid β-peptide (Aβ) in the brain causing neurodegeneration and familial Alzheimer's disease (AD), over 95% of all AD cases are sporadic. Despite the pathologies being indistinguishable, relatively little is known about the mechanisms affecting generation of Aβ in the sporadic cases. Vascular disorders such as ischaemia and stroke are well established risk factors for the development of neurodegenerative diseases and systemic hypoxic episodes have been shown to increase Aβ production and accumulation. We have previously shown that hypoxia causes a significant decrease in the expression of the major Aβ-degrading enzyme neprilysin (NEP) which might deregulate Aβ clearance. Aβ itself is derived from the transmembrane APP along with several other biologically active metabolites including the C-terminal fragment (CTF) termed the APP intracellular domain (AICD), which regulates the expression of NEP and some other genes in neuronal cells. Here we show that in hypoxia there is a significantly increased expression of caspase-3, 8, and 9 in human neuroblastoma NB7 cells, which can degrade AICD. Using chromatin immunoprecipitation we have revealed that there was also a reduction of AICD bound to the NEP promoter region which underlies the decreased expression and activity of the enzyme under hypoxic conditions. Incubation of the cells with a caspase-3 inhibitor Z-DEVD-FMK could rescue the effect of hypoxia on NEP activity protecting the levels of AICD capable of binding the NEP promoter. These data suggest that activation of caspases might play an important role in regulation of NEP levels in the brain under pathological conditions such as hypoxia and ischaemia leading to a deficit of Aβ clearance and increasing the risk of development of AD.
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Affiliation(s)
- Caroline Kerridge
- Faculty of Biological Sciences, School of Molecular and Cellular Biology, University of Leeds Leeds, UK ; Neuroscience, Eli Lilly and Company Limited, Lilly Research Centre Surrey, UK
| | - Daria I Kozlova
- I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences St. Petersburg, Russia
| | - Natalia N Nalivaeva
- Faculty of Biological Sciences, School of Molecular and Cellular Biology, University of Leeds Leeds, UK ; I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences St. Petersburg, Russia
| | - Anthony J Turner
- Faculty of Biological Sciences, School of Molecular and Cellular Biology, University of Leeds Leeds, UK
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22
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Kovacs GG, Horvath MC, Majtenyi K, Lutz MI, Hurd YL, Keller E. Heroin abuse exaggerates age-related deposition of hyperphosphorylated tau and p62-positive inclusions. Neurobiol Aging 2015; 36:3100-3107. [PMID: 26254956 PMCID: PMC4609594 DOI: 10.1016/j.neurobiolaging.2015.07.018] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 07/06/2015] [Accepted: 07/11/2015] [Indexed: 11/26/2022]
Abstract
The observation of increased hyperphosphorylated tau levels correlating with microglial activation in opiate abusers has been interpreted as predisposition to accelerated Alzheimer disease-related changes. The present study focused on evaluating additional neurodegeneration-related proteins, including α-synuclein and TDP-43, and p62-positive deposits. We performed a systematic mapping of protein deposits in the brains of 27 individuals with documented heroin addiction (age: 19-40 years) and compared with 11 controls (age: 15-40 years). We confirm previous findings that heroin addiction associates with tau hyperphosphorylation in predilection brain areas for aging and Alzheimer disease. Furthermore, we show that this occurs also in areas implicated in the molecular disturbances and in vivo neuronal networks related to heroin abuse. There was, however, no presence of amyloid-beta deposits. We extend previous findings by showing the lack of TDP-43 or α-synuclein pathology and emphasize the independent effect of the duration of drug use on the appearance of age-related p62-positive neuritic profiles. These observations provide unique insights about neuropathological alterations in the brains of young heroin addicts and have implications about brain aging and the influences of environmental and toxic factors.
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Affiliation(s)
- Gabor G Kovacs
- Institute of Neurology, Medical University of Vienna, Vienna, Austria; Neuropathology and Prion Disease Reference Center, Semmelweis University, Budapest, Hungary.
| | - Monika Cs Horvath
- Department of Forensic Medicine, National Board of Forensic Medicine, Uppsala University, Uppsala, Sweden
| | - Katalin Majtenyi
- Neuropathology and Prion Disease Reference Center, Semmelweis University, Budapest, Hungary
| | - Mirjam I Lutz
- Institute of Neurology, Medical University of Vienna, Vienna, Austria
| | - Yasmin L Hurd
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Eva Keller
- Department of Forensic and Insurance Medicine, Semmelweis University, Budapest, Hungary.
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23
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Miller MA. The Role of Sleep and Sleep Disorders in the Development, Diagnosis, and Management of Neurocognitive Disorders. Front Neurol 2015; 6:224. [PMID: 26557104 PMCID: PMC4615953 DOI: 10.3389/fneur.2015.00224] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 10/12/2015] [Indexed: 12/31/2022] Open
Abstract
It is becoming increasingly apparent that sleep plays an important role in the maintenance, disease prevention, repair, and restoration of both mind and body. The sleep and wake cycles are controlled by the pacemaker activity of the superchiasmic nucleus in the hypothalamus but can be disrupted by diseases of the nervous system causing disordered sleep. A lack of sleep has been associated with an increase in all-cause mortality. Likewise, sleep disturbances and sleep disorders may disrupt neuronal pathways and have an impact on neurological diseases. Sleep deprivation studies in normal subjects demonstrate that a lack of sleep can cause attention and working memory impairment. Moreover, untreated sleep disturbances and sleep disorders such as obstructive sleep apnoe (OSA) can also lead to cognitive impairment. Poor sleep and sleep disorders may present a significant risk factor for the development of dementia. In this review, the underlying mechanisms and the role of sleep and sleep disorders in the development of neurocognitive disorders [dementia and mild cognitive impairment (MCI)] and how the presence of sleep disorders could direct the process of diagnosis and management of neurocognitive disorders will be discussed.
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24
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Daulatzai MA. Evidence of neurodegeneration in obstructive sleep apnea: Relationship between obstructive sleep apnea and cognitive dysfunction in the elderly. J Neurosci Res 2015; 93:1778-94. [DOI: 10.1002/jnr.23634] [Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 08/02/2015] [Accepted: 08/04/2015] [Indexed: 02/06/2023]
Affiliation(s)
- Mak Adam Daulatzai
- Sleep Disorders Group, EEE/Melbourne School of Engineering, The University of Melbourne; Parkville Victoria Australia
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25
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D'Alton S, Lewis J. Therapeutic and diagnostic challenges for frontotemporal dementia. Front Aging Neurosci 2014; 6:204. [PMID: 25191265 PMCID: PMC4137452 DOI: 10.3389/fnagi.2014.00204] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 07/25/2014] [Indexed: 12/12/2022] Open
Abstract
In the search for therapeutic modifiers, frontotemporal dementia (FTD) has traditionally been overshadowed by other conditions such as Alzheimer's disease (AD). A clinically and pathologically diverse condition, FTD has been galvanized by a number of recent discoveries such as novel genetic variants in familial and sporadic forms of disease and the identification of TAR DNA binding protein of 43 kDa (TDP-43) as the defining constituent of inclusions in more than half of cases. In combination with an ever-expanding knowledge of the function and dysfunction of tau-a protein which is pathologically aggregated in the majority of the remaining cases-there exists a greater understanding of FTD than ever before. These advances may indicate potential approaches for the development of hypothetical therapeutics, but FTD remains highly complex and the roles of tau and TDP-43 in neurodegeneration are still wholly unclear. Here the challenges facing potential therapeutic strategies are discussed, which include sufficiently accurate disease diagnosis and sophisticated technology to deliver effective therapies.
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Affiliation(s)
- Simon D'Alton
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida Gainesville, FL, USA
| | - Jada Lewis
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida Gainesville, FL, USA
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26
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Zhang CE, Yang X, Li L, Sui X, Tian Q, Wei W, Wang J, Liu G. Hypoxia-induced tau phosphorylation and memory deficit in rats. NEURODEGENER DIS 2014; 14:107-16. [PMID: 24993525 DOI: 10.1159/000362239] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 03/17/2014] [Indexed: 11/19/2022] Open
Abstract
Hypoxia was shown to be associated with an increased risk of Alzheimer's disease (AD). The effects of hypoxia on the development of AD pathology and spatial memory ability and the possible molecular mechanisms remain poorly understood. In this study, we demonstrate that rats exposed to a hypoxic condition (10% oxygen concentration) for 1, 2, 4 and 8 weeks (6 h each day) displayed spatial memory impairment and increased tau phosphorylation at Ser198/199/202, Thr205, Ser262, Ser396 and Ser404 in the hippocampus. Concomitantly, the levels of Tyr216-phosphorylated glycogen synthase kinase (GSK)-3β (activated form of GSK-3β) and Tyr307-phosphorylated protein phosphatase 2A (inactivated form of PP2A) were significantly increased in the hippocampus of the rats with 1, 2, 4 and 8 weeks of hypoxia exposure, while the levels of methylated PP2A (activated form of PP2A) were significantly decreased in the hippocampus of the rats with 4 and 8 weeks of hypoxia exposure. In addition, the content of malondialdehyde, an indicator of oxidative stress, was elevated, whereas the activity of superoxide dismutase was not significantly changed in the hippocampus of the rats exposed to hypoxia. Taken together, these data demonstrated that hypoxia induced tau hyperphosphorylation and memory impairment in rats, and that the increased tau phosphorylation could be attributed to activation of GSK-3β and inactivation of PP2A. These data suggest that interventions to improve hypoxia may be helpful to prevent the development of AD pathology and cognitive impairment.
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Affiliation(s)
- Chang-E Zhang
- Department of Pathophysiology, Guangzhou Medical University, Guangzhou, China
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27
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Lee MJ, Seo SW, Na DL, Kim C, Park JH, Kim GH, Kim CH, Noh Y, Cho H, Kim HJ, Yoon CW, Ye BS, Chin J, Jeon S, Lee JM, Choe YS, Lee KH, Kim JS, Kim ST, Lee JH, Ewers M, Werring DJ, Weiner MW. Synergistic effects of ischemia and β-amyloid burden on cognitive decline in patients with subcortical vascular mild cognitive impairment. JAMA Psychiatry 2014; 71:412-22. [PMID: 24554306 PMCID: PMC5849078 DOI: 10.1001/jamapsychiatry.2013.4506] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
IMPORTANCE Cerebrovascular disease (CVD) and Alzheimer disease are significant causes of cognitive impairment in the elderly. However, few studies have evaluated the relationship between CVD and β-amyloid burden in living humans or their synergistic effects on cognition. Thus, there is a need for better understanding of mild cognitive impairment (MCI) before clinical deterioration begins. OBJECTIVE To determine the synergistic effects of β-amyloid burden and CVD on cognition in patients with subcortical vascular MCI (svMCI). DESIGN, SETTING, AND PARTICIPANTS A cross-sectional study was conducted using a hospital-based sample at a tertiary referral center. We prospectively recruited 95 patients with svMCI; 67 of these individuals participated in the study. Forty-five patients with amnestic MCI (aMCI) were group matched with those with svMCI by the Clinical Dementia Rating Scale Sum of Boxes. MAIN OUTCOMES AND MEASURES We measured β-amyloid burden using positron emission tomography with carbon 11-labeled Pittsburgh Compound B (PiB). Cerebrovascular disease was quantified as white matter hyperintensity volume detected by magnetic resonance imaging fluid-attenuated inversion recovery. Detailed neuropsychological tests were performed to determine the level of patients' cognitive impairment. RESULTS On evaluation, 22 of the svMCI group (33%) and 28 of the aMCI group (62%) were found to be PiB positive. The mean PiB retention ratio was lower in patients with svMCI than in those with aMCI. In svMCI, the PiB retention ratio was associated with cognitive impairments in multiple domains, including language, visuospatial, memory, and frontal executive functions, but was associated only with memory dysfunction in aMCI. A significant interaction between PiB retention ratio and white matter hyperintensity volume was found to affect visuospatial function in patients with svMCI. CONCLUSIONS AND RELEVANCE Most patients with svMCI do not exhibit substantial amyloid burden, and CVD does not increase β-amyloid burden as measured by amyloid imaging. However, in patients with svMCI, amyloid burden and white matter hyperintensity act synergistically to impair visuospatial function. Therefore, our findings highlight the need for accurate biomarkers, including neuroimaging tools, for early diagnosis and the need to relate these biomarkers to cognitive measurements for effective use in the clinical setting.
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Affiliation(s)
- Mi Ji Lee
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Sang Won Seo
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Duk L Na
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Changsoo Kim
- Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Jae Hyun Park
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Geon Ha Kim
- Department of Neurology, Ewha Womans University Mokdong Hospital, Ewha Womans University School of Medicine, Seoul, Korea
| | - Chi Hun Kim
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Young Noh
- Department of Neurology, Gachon University Gil Medical Center, Incheon, Korea
| | - Hanna Cho
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea5Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Hee Jin Kim
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Cindy W Yoon
- Department of Neurology, Inha University School of Medicine, Incheon, Korea
| | - Byoung Seok Ye
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Juhee Chin
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Seun Jeon
- Department of Biomedical Engineering, Hanyang University, Seoul, Korea
| | - Jong-Min Lee
- Department of Biomedical Engineering, Hanyang University, Seoul, Korea
| | - Yearn Seong Choe
- Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Kyung-Han Lee
- Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Jae Seung Kim
- Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Sung Tae Kim
- Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Jae-Hong Lee
- Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Michael Ewers
- Institute for Stroke and Dementia Research, Ludwig-Maximilians University, Munich, Germany
| | - David J Werring
- Department of Brain Repair and Rehabilitation, University College London Institute of Neurology, Queen Square, London, England
| | - Michael W Weiner
- Department of Radiology, University of California, San Francisco15Center for Imaging of Neurodegenerative Diseases, Department of Veterans Affairs Medical Center, San Francisco, California
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Engelhardt S, Patkar S, Ogunshola OO. Cell-specific blood-brain barrier regulation in health and disease: a focus on hypoxia. Br J Pharmacol 2014; 171:1210-30. [PMID: 24641185 PMCID: PMC3952799 DOI: 10.1111/bph.12489] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 10/02/2013] [Accepted: 10/16/2013] [Indexed: 01/16/2023] Open
Abstract
The blood-brain barrier (BBB) is a complex vascular structure consisting of microvascular endothelial cells that line the vessel wall, astrocyte end-feet, pericytes, as well as the basal lamina. BBB cells act in concert to maintain the characteristic impermeable and low paracellular flux of the brain vascular network, thus ensuring a homeostatic neuronal environment. Alterations in BBB stability that occur during injury have dire consequences on disease progression and it is clear that BBB cell-specific responses, positive or negative, must make a significant contribution to injury outcome. Reduced oxygenation, or hypoxia, is a characteristic of many brain diseases that significantly increases barrier permeability. Recent data suggest that hypoxia-inducible factor (HIF-1), the master regulator of the hypoxic response, probably mediates many hypoxic effects either directly or indirectly via its target genes. This review discusses current knowledge of physiological cell-specific regulation of barrier function, their responses to hypoxia as well as consequences of hypoxic- and HIF-1-mediated mechanisms on barrier integrity during select brain diseases. In the final sections, the potential of current advances in targeting HIF-1 as a therapeutic strategy will be overviewed.
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Affiliation(s)
- S Engelhardt
- Institute of Veterinary Physiology, University of ZurichZurich, Switzerland
| | - S Patkar
- Institute of Veterinary Physiology, University of ZurichZurich, Switzerland
| | - O O Ogunshola
- Institute of Veterinary Physiology, University of ZurichZurich, Switzerland
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Yan J, Chen R, Liu P, Gu Y. Docosahexaenoic acid inhibits development of hypoxic pulmonary hypertension: In vitro and in vivo studies. Int J Cardiol 2013; 168:4111-6. [DOI: 10.1016/j.ijcard.2013.07.073] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Revised: 07/02/2013] [Accepted: 07/07/2013] [Indexed: 01/28/2023]
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Glodzik L, Rusinek H, Pirraglia E, McHugh P, Tsui W, Williams S, Cummings M, Li Y, Rich K, Randall C, Mosconi L, Osorio R, Murray J, Zetterberg H, Blennow K, de Leon M. Blood pressure decrease correlates with tau pathology and memory decline in hypertensive elderly. Neurobiol Aging 2013; 35:64-71. [PMID: 23969178 DOI: 10.1016/j.neurobiolaging.2013.06.011] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 06/12/2013] [Accepted: 06/18/2013] [Indexed: 01/01/2023]
Abstract
In hypertension (HTN), cerebral blood flow regulation limits are changed, and the threshold for blood pressure (BP) at which perfusion is safely maintained is higher. This shift may increase the brain's vulnerability to lower BP in subjects with vascular disease. We investigated whether longitudinal reduction in mean arterial pressure (MAP) was related to changes in cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease in a group of cognitively healthy elderly with and without HTN. The relationships among MAP, memory decline, and hippocampal atrophy were also examined. Seventy-seven subjects (age 63.4 ± 9.4, range 44-86 years; education 16.9 ± 2.1, range 10-22 years; 60% women) were assessed twice, 2 ± 0.5 years apart. At both time points, all subjects underwent full medical and neuropsychological evaluations, lumbar punctures, and magnetic resonance imaging examinations. Twenty-five subjects had HTN. Hyper- and normotensive subjects did not differ in their CSF biomarkers, hippocampal volumes (HipVs), or memory scores at baseline. In the entire study group, the increase in tau phosphorylated at threonine 181 (p-tau(181)) was associated with a decline in verbal episodic memory (β = -0.30, p = 0.01) and HipV reduction (β = -0.27, p = 0.02). However, longitudinal decrease in MAP was related to memory decline (β = 0.50, p = 0.01) and an increase in p-tau(181) (β = -0.50, p = 0.01) only in subjects with HTN. Our findings suggest that the hypertensive group may be sensitive to BP reductions.
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Affiliation(s)
- Lidia Glodzik
- Department of Psychiatry, Center for Brain Health, New York University School of Medicine, New York, NY, USA; Department of Radiology, New York University School of Medicine, New York, NY, USA.
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Tau hyperphosphorylation and increased BACE1 and RAGE levels in the cortex of PPARβ/δ-null mice. Biochim Biophys Acta Mol Basis Dis 2013; 1832:1241-8. [DOI: 10.1016/j.bbadis.2013.03.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 02/11/2013] [Accepted: 03/02/2013] [Indexed: 11/19/2022]
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Arendt T, Bullmann T. Neuronal plasticity in hibernation and the proposed role of the microtubule-associated protein tau as a "master switch" regulating synaptic gain in neuronal networks. Am J Physiol Regul Integr Comp Physiol 2013; 305:R478-89. [PMID: 23824962 DOI: 10.1152/ajpregu.00117.2013] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The present paper provides an overview of adaptive changes in brain structure and learning abilities during hibernation as a behavioral strategy used by several mammalian species to minimize energy expenditure under current or anticipated inhospitable environmental conditions. One cellular mechanism that contributes to the regulated suppression of metabolism and thermogenesis during hibernation is reversible phosphorylation of enzymes and proteins, which limits rates of flux through metabolic pathways. Reversible phosphorylation during hibernation also affects synaptic membrane proteins, a process known to be involved in synaptic plasticity. This mechanism of reversible protein phosphorylation also affects the microtubule-associated protein tau, thereby generating a condition that in the adult human brain is associated with aggregation of tau protein to paired helical filaments (PHFs), as observed in Alzheimer's disease. Here, we put forward the concept that phosphorylation of tau is a neuroprotective mechanism to escape NMDA-mediated hyperexcitability of neurons that would otherwise occur during slow gradual cooling of the brain. Phosphorylation of tau and its subsequent targeting to subsynaptic sites might, thus, work as a kind of "master switch," regulating NMDA receptor-mediated synaptic gain in a wide array of neuronal networks, thereby enabling entry into torpor. If this condition lasts too long, however, it may eventually turn into a pathological trigger, driving a cascade of events leading to neurodegeneration, as in Alzheimer's disease or other "tauopathies".
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Affiliation(s)
- Thomas Arendt
- Paul Flechsig Institute of Brain Research, Universität Leipzig, Germany.
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Death by a thousand cuts in Alzheimer's disease: hypoxia--the prodrome. Neurotox Res 2013; 24:216-43. [PMID: 23400634 DOI: 10.1007/s12640-013-9379-2] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 01/10/2013] [Accepted: 01/21/2013] [Indexed: 12/30/2022]
Abstract
A wide range of clinical consequences may be associated with obstructive sleep apnea (OSA) including systemic hypertension, cardiovascular disease, pulmonary hypertension, congestive heart failure, cerebrovascular disease, glucose intolerance, impotence, gastroesophageal reflux, and obesity, to name a few. Despite this, 82 % of men and 93 % of women with OSA remain undiagnosed. OSA affects many body systems, and induces major alterations in metabolic, autonomic, and cerebral functions. Typically, OSA is characterized by recurrent chronic intermittent hypoxia (CIH), hypercapnia, hypoventilation, sleep fragmentation, peripheral and central inflammation, cerebral hypoperfusion, and cerebral glucose hypometabolism. Upregulation of oxidative stress in OSA plays an important pathogenic role in the milieu of hypoxia-induced cerebral and cardiovascular dysfunctions. Strong evidence underscores that cerebral amyloidogenesis and tau phosphorylation--two cardinal features of Alzheimer's disease (AD), are triggered by hypoxia. Mice subjected to hypoxic conditions unambiguously demonstrated upregulation in cerebral amyloid plaque formation and tau phosphorylation, as well as memory deficit. Hypoxia triggers neuronal degeneration and axonal dysfunction in both cortex and brainstem. Consequently, neurocognitive impairment in apneic/hypoxic patients is attributable to a complex interplay between CIH and stimulation of several pathological trajectories. The framework presented here helps delineate the emergence and progression of cognitive decline, and may yield insight into AD neuropathogenesis. The global impact of CIH should provide a strong rationale for treating OSA and snoring clinically, in order to ameliorate neurocognitive impairment in aged/AD patients.
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Zhou F, Chen S, Xiong J, Li Y, Qu L. Luteolin reduces zinc-induced tau phosphorylation at Ser262/356 in an ROS-dependent manner in SH-SY5Y cells. Biol Trace Elem Res 2012; 149:273-9. [PMID: 22528780 DOI: 10.1007/s12011-012-9411-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 03/28/2012] [Indexed: 01/08/2023]
Abstract
In brain, excess zinc alters the metabolism of amyloid precursor protein, leading to β-amyloid protein deposition, one of the hallmarks of Alzheimer's disease (AD) pathology. Recently, it has been reported that zinc accelerates in vitro tau fibrillization, another hallmark of AD. In the current study, we examined the effect of high-concentration zinc on tau phosphorylation in human neuroblastoma SH-SY5Y cells. We found that incubation of cells with zinc resulted in abnormal tau phosphorylation at Ser262/356. Moreover, the current study has investigated whether luteolin (Lu), a bioflavonoid, could decrease zinc-induced tau hyperphosphorylation and its underlying mechanisms. Using Western blot and protein phosphatase activity assay, activities of tau kinases and phosphatase were investigated. Our data suggest (1) that zinc induces tau hyperphosphorylation at Ser262/356 epitope and (2) that Lu efficiently attenuates zinc-induced tau hyperphosphorylation through not only its antioxidant action but also its regulation of the phosphorylation/dephosphorylation system.
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Affiliation(s)
- Futao Zhou
- School of Physical Education, Nanchang Hangkong University, Nanchang, Jiangxi, 330063, China.
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Zhang H, Li W, Sun S, Yu S, Zhang M, Zou F. Inhibition of sphingosine kinase 1 suppresses proliferation of glioma cells under hypoxia by attenuating activity of extracellular signal-regulated kinase. Cell Prolif 2012; 45:167-75. [PMID: 22288844 DOI: 10.1111/j.1365-2184.2012.00807.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
OBJECTIVES Sphingosine kinase (SphK), which is regulated by hypoxia, catalyses phosphorylation of sphingosine to produce sphingosine-1-phosphate, which stimulates invasiveness of gliomas. However, whether SphK is involved in proliferation of glioma cells under hypoxic conditions is not clearly understood. In this study, we have investigated the role of SphK in of proliferation glioma cells under hypoxia. MATERIALS AND METHODS Effects of small interfering RNA (siRNA) on SphKs, SKI (inhibitor of SphK) and U0126 (inhibitor of ERK) on proliferation of glioma cells under hypoxia were studied using CCK-8 assay and flow cytometry. Protein expression profiles were evaluated by Western blot analysis. RESULTS SKI suppressed proliferation of glioma cells under hypoxia. Similarly, downregulation of SphKs by siRNA inhibited glioma cell proliferation, and the cell cycle was arrested in G(2) /M phase when SphK1 was inhibited. In addition, inhibition of SphK1 attenuated phosphorylation of ERK in hypoxic conditions. Furthermore, U0126 markedly inhibited cell population growth and arrested cells in G(2) /M as effectively as SKI. However, silencing SphK2 induced cell cycle arrest in the S phase and it showed little effect on hypoxia-induced activation of ERK. CONCLUSIONS SphK1 and SphK2 are involved in proliferation of glioma cells in hypoxic conditions through distinct signalling pathways. SphK1, but not SphK2, promotes cell population expansion in hypoxic conditions by activating ERK.
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Affiliation(s)
- H Zhang
- Department of Occupational Health and Occupational Medicine, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong, China
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Zlokovic BV. Neurovascular pathways to neurodegeneration in Alzheimer's disease and other disorders. Nat Rev Neurosci 2011; 12:723-38. [PMID: 22048062 DOI: 10.1038/nrn3114] [Citation(s) in RCA: 1979] [Impact Index Per Article: 152.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The neurovascular unit (NVU) comprises brain endothelial cells, pericytes or vascular smooth muscle cells, glia and neurons. The NVU controls blood-brain barrier (BBB) permeability and cerebral blood flow, and maintains the chemical composition of the neuronal 'milieu', which is required for proper functioning of neuronal circuits. Recent evidence indicates that BBB dysfunction is associated with the accumulation of several vasculotoxic and neurotoxic molecules within brain parenchyma, a reduction in cerebral blood flow, and hypoxia. Together, these vascular-derived insults might initiate and/or contribute to neuronal degeneration. This article examines mechanisms of BBB dysfunction in neurodegenerative disorders, notably Alzheimer's disease, and highlights therapeutic opportunities relating to these neurovascular deficits.
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Affiliation(s)
- Berislav V Zlokovic
- Department of Physiology and Biophysics, and Center for Neurodegeneration and Regeneration at the Zilkha Neurogenetic Institute, University of Southern California, Keck School of Medicine, 1501 San Pablo Street, Los Angeles, California 90089, USA.
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Wang Y, Hu X, Xie X, He A, Liu X, Wang JA. Effects of mesenchymal stem cells on matrix metalloproteinase synthesis in cardiac fibroblasts. Exp Biol Med (Maywood) 2011; 236:1197-204. [PMID: 21856754 DOI: 10.1258/ebm.2011.010317] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Mesenchymal stem cell (MSC) transplantation has been known to decrease matrix metalloproteinase (MMP) synthesis in myocardium after myocardial infarction (MI) and improve ventricular remodeling; however, the underlying mechanisms are unclear. This study investigated the effects of MSC on MMP synthesis in cardiac fibroblasts (CFs) through paracrine actions. CFs were cultured under hypoxic (0.5% pO(2)) conditions for 24 h before co-culture with MSCs or hypoxia-preconditioned MSCs (H-MSCs) in transwell plates. CFs and MSCs/H-MSCs shared a medium with or without erythropoietin (EPO) neutralizing antibody (EPOAb) or EPO-soluble receptor (EPOsR). The results showed that protein expression and activity of MMP-2 and membrane type 1-MMP, but not MMP-9, in CFs were significantly increased in response to hypoxia and decreased after co-culture with MSCs or H-MSCs. Hypoxia up-regulated phosphorylation of extracellular signal-regulated kinase (ERK)1/2 of CFs which was down-regulated after CFs' co-culture with MSCs. Tissue inhibitors of metalloproteinases-1 (TIMP-1) in CFs was decreased after hypoxia and increased when co-cultured with MSCs or H-MSCs. Exogenous EPOAb or EPOsR partially inhibited MSCs' effect on MMP-2 expression and activity in CFs. The present findings suggested that MSCs influence MMP/TIMP expression in CFs via the ERK1/2 pathway and EPO acts as a key factor in the paracrine actions of MSCs.
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Affiliation(s)
- Yaping Wang
- Cardiovascular Center, Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, 310009, PR China
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Upregulation of transcription factor NRF2-mediated oxidative stress response pathway in rat brain under short-term chronic hypobaric hypoxia. Funct Integr Genomics 2010; 11:119-37. [PMID: 20922447 DOI: 10.1007/s10142-010-0195-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 08/06/2010] [Accepted: 09/13/2010] [Indexed: 02/03/2023]
Abstract
Exposure to high altitude (and thus hypobaric hypoxia) induces electrophysiological, metabolic, and morphological modifications in the brain leading to several neurological clinical syndromes. Despite the known fact that hypoxia episodes in brain are a common factor for many neuropathologies, limited information is available on the underlying cellular and molecular mechanisms. In this study, we investigated the temporal effect of short-term (0-12 h) chronic hypobaric hypoxia on global gene expression of rat brain followed by detailed canonical pathway analysis and regulatory network identification. Our analysis revealed significant alteration of 33, 17, 53, 81, and 296 genes (p < 0.05, <1.5-fold) after 0.5, 1, 3, 6, and 12 h of hypoxia, respectively. Biological processes like regulation, metabolic, and transport pathways are temporally activated along with anti- and proinflammatory signaling networks like PI3K/AKT, NF-κB, ERK/MAPK, IL-6 and IL-8 signaling. Irrespective of exposure durations, nuclear factor (erythroid-derived 2)-like 2 (NRF2)-mediated oxidative stress response pathway and genes were detected at all time points suggesting activation of NRF2-ARE antioxidant defense system. The results were further validated by assessing the expression levels of selected genes in temporal as well as brain regions with quantitative RT-PCR and western blot. In conclusion, our whole brain approach with temporal monitoring of gene expression patterns during hypobaric hypoxia has resulted in (1) deciphering sequence of pathways and signaling networks activated during onset of hypoxia, and (2) elucidation of NRF2-orchestrated antioxidant response as a major intrinsic defense mechanism. The results of this study will aid in better understanding and management of hypoxia-induced brain pathologies.
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